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tauri/.gitignore

@@ -0,0 +1,2 @@
+/target/
+/gen/

tauri/Cargo.toml

@@ -0,0 +1,24 @@
+[package]
+name = "gpx-studio-desktop"
+version = "0.1.0"
+description = "Desktop shell for gpx.studio"
+edition = "2021"
+
+[lib]
+name = "gpx_studio_desktop_lib"
+crate-type = ["staticlib", "cdylib", "rlib"]
+
+[dev-dependencies]
+tauri = { version = "2", features = ["test"] }
+
+[build-dependencies]
+tauri-build = { version = "2", features = [] }
+
+[dependencies]
+tauri = { version = "2", features = [] }
+serde = { version = "1", features = ["derive"] }
+serde_json = "1"
+uuid = { version = "1", features = ["serde"] }
+gpx-engine = { path = "../gpx-rs/engine" }
+
+[workspace]

tauri/build.rs

@@ -0,0 +1,3 @@
+fn main() {
+    tauri_build::build()
+}

tauri/capabilities/default.json

@@ -0,0 +1,7 @@
+{
+    "$schema": "../gen/schemas/desktop-schema.json",
+    "identifier": "default",
+    "description": "Permissions for the main window",
+    "windows": ["main"],
+    "permissions": ["core:default"]
+}

tauri/package.json

@@ -0,0 +1,8 @@
+{
+    "name": "tauri",
+    "private": true,
+    "scripts": {
+        "dev": "cargo tauri dev",
+        "build": "cargo tauri build"
+    }
+}

tauri/src/commands/edit.rs

@@ -0,0 +1,246 @@
+//! Editing the metadata, the style, the structure and the waypoints of the files, and the tools:
+//! reversing, cropping, reducing, timestamps, merging, cleaning...
+
+use gpx_engine::{self as engine, Command, LngLat, LngLatBounds};
+use tauri::State;
+use uuid::Uuid;
+
+use crate::dto::*;
+use crate::state::{act, edit, AppState};
+
+#[tauri::command(async)]
+pub fn metadata(state: State<AppState>, name: String, desc: String) -> Outcome {
+    edit!(
+        state,
+        Command::Metadata(engine::Metadata {
+            name: &name,
+            desc: &desc,
+        })
+    )
+}
+
+#[tauri::command(async)]
+pub fn style(
+    state: State<AppState>,
+    color: Option<String>,
+    opacity: Option<f64>,
+    width: Option<f64>,
+) -> Outcome {
+    edit!(
+        state,
+        Command::Style(engine::Style {
+            color: color.as_deref(),
+            opacity,
+            width,
+        })
+    )
+}
+
+#[tauri::command(async)]
+pub fn new_track(state: State<AppState>) -> Outcome {
+    edit!(state, Command::NewTrack(engine::NewTrack))
+}
+
+#[tauri::command(async)]
+pub fn new_track_segment(state: State<AppState>) -> Outcome {
+    edit!(state, Command::NewTrackSegment(engine::NewTrackSegment))
+}
+
+// Waypoints
+
+#[tauri::command(async)]
+#[allow(clippy::too_many_arguments)]
+pub fn new_waypoint(
+    state: State<AppState>,
+    lng: f64,
+    lat: f64,
+    ele: f64,
+    name: String,
+    desc: String,
+    icon: String,
+    link: String,
+) -> Outcome {
+    edit!(
+        state,
+        Command::NewWaypoint(engine::NewWaypoint {
+            lng,
+            lat,
+            ele,
+            name: &name,
+            desc: &desc,
+            icon: &icon,
+            link: &link,
+        })
+    )
+}
+
+#[tauri::command(async)]
+pub fn move_waypoint(
+    state: State<AppState>,
+    file_id: Uuid,
+    waypoint_id: Uuid,
+    lng: f64,
+    lat: f64,
+    ele: f64,
+) -> Outcome {
+    edit!(
+        state,
+        Command::MoveWaypoint(engine::MoveWaypoint {
+            file_id: engine::FileId(file_id),
+            waypoint_id: engine::WaypointId(waypoint_id),
+            lng,
+            lat,
+            ele,
+        })
+    )
+}
+
+#[tauri::command(async)]
+pub fn delete_waypoint(state: State<AppState>, file_id: Uuid, waypoint_id: Uuid) -> Outcome {
+    edit!(
+        state,
+        Command::DeleteWaypoint(engine::DeleteWaypoint {
+            file_id: engine::FileId(file_id),
+            waypoint_id: engine::WaypointId(waypoint_id),
+        })
+    )
+}
+
+#[tauri::command(async)]
+#[allow(clippy::too_many_arguments)]
+pub fn update_waypoint(
+    state: State<AppState>,
+    file_id: Uuid,
+    waypoint_id: Uuid,
+    lng: f64,
+    lat: f64,
+    ele: f64,
+    name: String,
+    desc: String,
+    icon: String,
+    link: String,
+) -> Outcome {
+    edit!(
+        state,
+        Command::EditWaypoint(engine::EditWaypoint {
+            file_id: engine::FileId(file_id),
+            waypoint_id: engine::WaypointId(waypoint_id),
+            lng,
+            lat,
+            ele,
+            name: &name,
+            desc: &desc,
+            icon: &icon,
+            link: &link,
+        })
+    )
+}
+
+// Tools
+
+#[tauri::command(async)]
+pub fn reverse(state: State<AppState>) -> Outcome {
+    edit!(state, Command::Reverse(engine::Reverse))
+}
+
+#[tauri::command(async)]
+pub fn round_trip(state: State<AppState>) -> Outcome {
+    edit!(state, Command::RoundTrip(engine::RoundTrip))
+}
+
+#[tauri::command(async)]
+pub fn crop(state: State<AppState>, start: u32, end: u32) -> Outcome {
+    if start > end {
+        return Outcome::failed(format!("the range {start}..{end} is reversed"));
+    }
+    edit!(state, Command::Crop(engine::Crop { start, end }))
+}
+
+#[tauri::command(async)]
+pub fn reduce(state: State<AppState>, tolerance: f64) -> Outcome {
+    edit!(state, Command::Reduce(engine::Reduce { tolerance }))
+}
+
+#[tauri::command(async)]
+pub fn change_timestamps(
+    state: State<AppState>,
+    start_time: f64,
+    speed: f64,
+    ratio: f64,
+) -> Outcome {
+    edit!(
+        state,
+        Command::Time(engine::Time {
+            start_time: start_time as i64,
+            kind: engine::TimeKind::Change { speed, ratio },
+        })
+    )
+}
+
+#[tauri::command(async)]
+pub fn create_artificial_timestamps(
+    state: State<AppState>,
+    start_time: f64,
+    total_time: f64,
+) -> Outcome {
+    edit!(
+        state,
+        Command::Time(engine::Time {
+            start_time: start_time as i64,
+            kind: engine::TimeKind::Artificial { total_time },
+        })
+    )
+}
+
+#[tauri::command(async)]
+pub fn merge(state: State<AppState>, merge_type: MergeType, remove_gaps: bool) -> Outcome {
+    edit!(
+        state,
+        Command::Merge(engine::Merge {
+            type_: merge_type.into(),
+            remove_gaps,
+        })
+    )
+}
+
+#[tauri::command(async)]
+pub fn extract(state: State<AppState>) -> Outcome {
+    edit!(state, Command::Extract(engine::Extract))
+}
+
+#[tauri::command(async)]
+pub fn elevation(state: State<AppState>, ele: Vec<f64>) -> Outcome {
+    edit!(state, Command::Elevation(engine::Elevation { ele: &ele }))
+}
+
+#[tauri::command(async)]
+#[allow(clippy::too_many_arguments)]
+pub fn clean(
+    state: State<AppState>,
+    west: f64,
+    south: f64,
+    east: f64,
+    north: f64,
+    clean_type: CleanType,
+    trkpt: bool,
+    wpt: bool,
+) -> Outcome {
+    edit!(
+        state,
+        Command::Clean(engine::Clean {
+            bounds: LngLatBounds {
+                sw: LngLat {
+                    lng: west,
+                    lat: south,
+                },
+                ne: LngLat {
+                    lng: east,
+                    lat: north,
+                },
+            },
+            type_: clean_type.into(),
+            trkpt,
+            wpt,
+        })
+    )
+}

tauri/src/commands/files.rs

@@ -0,0 +1,161 @@
+//! Creating, loading, deleting, moving, copying and pasting files and their elements, and undoing.
+
+use gpx_engine::{self as engine, Action, Command};
+use tauri::ipc::{InvokeBody, Request};
+use tauri::State;
+use uuid::Uuid;
+
+use crate::dto::*;
+use crate::state::{act, edit, AppState};
+
+#[tauri::command(async)]
+pub fn new_file(
+    state: State<AppState>,
+    name: String,
+    lng: Option<f64>,
+    lat: Option<f64>,
+    ele: Option<f64>,
+) -> Outcome {
+    let trackpoint = lng.zip(lat).map(|(lng, lat)| engine::NewTrackpoint {
+        lng,
+        lat,
+        ele: ele.unwrap_or_default(),
+    });
+    edit!(
+        state,
+        Command::New(engine::New {
+            name: &name,
+            trackpoint,
+        })
+    )
+}
+
+/// The files are in the body, one after the other, the headers `lengths` and `names` (JSON) telling
+/// the number of bytes and the name of each one.
+#[tauri::command(async)]
+pub fn load_files(state: State<AppState>, request: Request<'_>) -> Outcome {
+    let InvokeBody::Raw(data) = request.body() else {
+        return Outcome::failed("the files are missing");
+    };
+    let header = |key: &str| {
+        request
+            .headers()
+            .get(key)
+            .and_then(|value| value.to_str().ok())
+            .and_then(urlencoding_decode)
+    };
+    let (Some(lengths), Some(names)) = (
+        header("lengths").and_then(|json| serde_json::from_str::<Vec<usize>>(&json).ok()),
+        header("names").and_then(|json| serde_json::from_str::<Vec<String>>(&json).ok()),
+    ) else {
+        return Outcome::failed("the lengths or the names of the files are not valid");
+    };
+    if lengths.len() != names.len() {
+        return Outcome::failed(format!(
+            "{} lengths for {} names",
+            lengths.len(),
+            names.len()
+        ));
+    }
+    let (data, mut offset) = (data.clone(), 0);
+    let mut ranges = Vec::with_capacity(names.len());
+    for (length, name) in lengths.iter().zip(&names) {
+        let end = offset + length;
+        if end > data.len() {
+            return Outcome::failed(format!("the data of {name} is shorter than its length"));
+        }
+        ranges.push(offset..end);
+        offset = end;
+    }
+    edit!(state, {
+        let files = ranges
+            .into_iter()
+            .zip(&names)
+            .map(|(range, name)| engine::Load {
+                data: &data[range],
+                name,
+            })
+            .collect();
+        Command::LoadFiles(engine::LoadFiles { files })
+    })
+}
+
+/// Headers are ASCII: the frontend percent-encodes the JSON.
+fn urlencoding_decode(value: &str) -> Option<String> {
+    let bytes = value.as_bytes();
+    let mut decoded = Vec::with_capacity(bytes.len());
+    let mut i = 0;
+    while i < bytes.len() {
+        if bytes[i] == b'%' {
+            let hex = value.get(i + 1..i + 3)?;
+            decoded.push(u8::from_str_radix(hex, 16).ok()?);
+            i += 3;
+        } else {
+            decoded.push(bytes[i]);
+            i += 1;
+        }
+    }
+    String::from_utf8(decoded).ok()
+}
+
+#[tauri::command(async)]
+pub fn duplicate(state: State<AppState>) -> Outcome {
+    edit!(state, Command::Duplicate(engine::Duplicate))
+}
+
+#[tauri::command(async)]
+pub fn delete(state: State<AppState>, whole_files: bool) -> Outcome {
+    edit!(state, Command::Delete(engine::Delete { whole_files }))
+}
+
+#[tauri::command(async)]
+pub fn delete_all(state: State<AppState>) -> Outcome {
+    edit!(state, Command::DeleteAll(engine::DeleteAll))
+}
+
+#[tauri::command(async)]
+pub fn reorder(state: State<AppState>, file_ids: Vec<Uuid>, index: usize) -> Outcome {
+    act!(
+        state,
+        Action::Reorder {
+            file_ids: file_ids.into_iter().map(engine::FileId).collect(),
+            index,
+        }
+    )
+}
+
+#[tauri::command(async)]
+pub fn copy(state: State<AppState>) -> Outcome {
+    act!(state, Action::Copy)
+}
+
+#[tauri::command(async)]
+pub fn cut(state: State<AppState>) -> Outcome {
+    act!(state, Action::Cut)
+}
+
+#[tauri::command(async)]
+pub fn paste(state: State<AppState>) -> Outcome {
+    edit!(state, Command::Paste(engine::Paste))
+}
+
+#[tauri::command(async)]
+pub fn move_elements(state: State<AppState>, what: Selection, to: MoveTarget) -> Outcome {
+    edit!(
+        state,
+        Command::Move(engine::Move {
+            what: what.into(),
+            to: to.into(),
+        })
+    )
+}
+
+#[tauri::command(async)]
+pub fn undo(state: State<AppState>) -> Outcome {
+    act!(state, Action::Undo)
+}
+
+#[tauri::command(async)]
+pub fn redo(state: State<AppState>) -> Outcome {
+    act!(state, Action::Redo)
+}

tauri/src/commands/mod.rs

@@ -0,0 +1,14 @@
+//! The functions of the frontend's interface to the engine, as Tauri commands. They are the
+//! counterparts of the functions that `gpx-rs/wasm` exports, and cross the same data: see
+//! `website/src/lib/engine/backend`.
+//!
+//! The commands that edit the files or change the selection return an `Outcome`.
+//! They are `async` (so they run off the main thread), the frontend sends them one after the other.
+
+pub mod edit;
+pub mod files;
+pub mod queries;
+pub mod routing;
+pub mod selection;
+pub mod statistics;
+pub mod storage;

tauri/src/commands/queries.rs

@@ -0,0 +1,136 @@
+//! The files, their structure and statistics, the selection, the clipboard, and the coordinates of
+//! the trackpoints and waypoints (flat `[lng, lat, ...]` little-endian `f64` arrays).
+
+use gpx_engine::{self as engine, FileId};
+use tauri::State;
+use uuid::Uuid;
+
+use crate::dto::*;
+use crate::state::AppState;
+
+#[tauri::command(async)]
+pub fn file_order(state: State<AppState>) -> Vec<String> {
+    state.read(|e| ids(e.order()))
+}
+
+#[tauri::command(async)]
+pub fn file_structure(state: State<AppState>, file_id: Uuid) -> Option<FileStructure> {
+    state.read(move |e| e.file_structure(&FileId(file_id)).map(FileStructure::new))
+}
+
+#[tauri::command(async)]
+pub fn file_statistics(state: State<AppState>, file_id: Uuid) -> Option<GlobalStatistics> {
+    state.read(move |e| {
+        e.file_statistics(&FileId(file_id))
+            .map(|s| GlobalStatistics::new(&s))
+    })
+}
+
+#[tauri::command(async)]
+pub fn selection(state: State<AppState>) -> Selection {
+    state.read(|e| e.selection().into())
+}
+
+#[tauri::command(async)]
+pub fn clipboard(state: State<AppState>) -> Option<Clipboard> {
+    state.read(|e| e.clipboard().map(Clipboard::new))
+}
+
+#[tauri::command(async)]
+pub fn can_undo(state: State<AppState>) -> bool {
+    state.read(|e| e.can_undo())
+}
+
+#[tauri::command(async)]
+pub fn can_redo(state: State<AppState>) -> bool {
+    state.read(|e| e.can_redo())
+}
+
+#[tauri::command(async)]
+pub fn can_paste(state: State<AppState>) -> bool {
+    state.read(|e| e.can_paste())
+}
+
+#[tauri::command(async)]
+pub fn waypoint(
+    state: State<AppState>,
+    file_id: Uuid,
+    waypoint_id: Uuid,
+) -> Option<WaypointDetails> {
+    state.read(move |e| {
+        e.waypoint(&FileId(file_id), &engine::WaypointId(waypoint_id))
+            .map(WaypointDetails::new)
+    })
+}
+
+#[tauri::command(async)]
+pub fn trackpoint(
+    state: State<AppState>,
+    file_id: Uuid,
+    segment_id: Uuid,
+    index: usize,
+) -> Option<TrackpointDetails> {
+    state.read(move |e| {
+        e.trackpoint(&FileId(file_id), &engine::TrackSegmentId(segment_id), index)
+            .map(TrackpointDetails::new)
+    })
+}
+
+/// A file as GPX (UTF-8 bytes), the first byte telling whether the file exists.
+#[tauri::command(async)]
+#[allow(clippy::too_many_arguments)]
+pub fn export_file(
+    state: State<AppState>,
+    file_id: Uuid,
+    time: bool,
+    hr: bool,
+    cad: bool,
+    atemp: bool,
+    power: bool,
+    osm: bool,
+    as_route: bool,
+) -> Bytes {
+    let options = engine::ExportOptions {
+        time,
+        hr,
+        cad,
+        atemp,
+        power,
+        osm,
+        as_route,
+    };
+    optional(state.read(move |e| e.export(&FileId(file_id), options)))
+}
+
+/// The data that some files have: a bit for the time (1), heart rate (2), cadence (4), temperature
+/// (8), power (16) and the OpenStreetMap data (32).
+#[tauri::command(async)]
+pub fn exportable_data(state: State<AppState>, file_ids: Vec<Uuid>) -> u8 {
+    state.read(move |e| {
+        let ids: Vec<FileId> = file_ids.into_iter().map(FileId).collect();
+        let data = e.exportable_data(&ids);
+        [
+            data.time, data.hr, data.cad, data.atemp, data.power, data.osm,
+        ]
+        .iter()
+        .enumerate()
+        .fold(0, |bits, (i, on)| bits | (u8::from(*on) << i))
+    })
+}
+
+#[tauri::command(async)]
+pub fn reduction_distances(state: State<AppState>) -> Bytes {
+    Bytes::new(state.read(|e| f64s(&e.reduction_distances())))
+}
+
+#[tauri::command(async)]
+pub fn segment_coordinates(state: State<AppState>, segment_id: Uuid) -> Bytes {
+    Bytes::new(
+        state.read(move |e| f64s(e.segment_coordinates(&engine::TrackSegmentId(segment_id)))),
+    )
+}
+
+#[tauri::command(async)]
+pub fn waypoint_coordinates(state: State<AppState>, file_id: Uuid) -> Bytes {
+    Bytes::new(state.read(move |e| f64s(e.waypoint_coordinates(&FileId(file_id)))))
+}

tauri/src/commands/routing.rs

@@ -0,0 +1,73 @@
+//! The commands that refer to trackpoints by their index in the routing buffers, which only mean
+//! something for the `revision` they were read with: the commands do nothing if the selection is
+//! not the one of that revision anymore.
+
+use gpx_engine::{self as engine, Command};
+use tauri::State;
+
+use crate::dto::*;
+use crate::state::{edit_at, AppState};
+
+#[tauri::command(async)]
+#[allow(clippy::too_many_arguments)]
+pub fn route(
+    state: State<AppState>,
+    revision: u32,
+    start: u32,
+    end: u32,
+    lng: Vec<f64>,
+    lat: Vec<f64>,
+    ele: Vec<f64>,
+    attributes: RouteAttributes,
+    anchors: Vec<u32>,
+) -> Outcome {
+    if lng.len() != lat.len() || lat.len() != ele.len() {
+        return Outcome::failed("lng, lat and ele differ in length");
+    }
+    edit_at!(
+        state,
+        revision,
+        Command::Route(engine::Route {
+            start,
+            end,
+            lng: &lng,
+            lat: &lat,
+            ele: &ele,
+            surface: attributes.surface.view(),
+            highway: attributes.highway.view(),
+            sac_scale: attributes.sac_scale.view(),
+            mtb_scale: attributes.mtb_scale.view(),
+            anchors: &anchors,
+        })
+    )
+}
+
+#[tauri::command(async)]
+pub fn insert_anchor(state: State<AppState>, revision: u32, lng: f64, lat: f64) -> Outcome {
+    edit_at!(
+        state,
+        revision,
+        Command::InsertAnchor(engine::InsertAnchor { lng, lat })
+    )
+}
+
+#[tauri::command(async)]
+pub fn change_loop_start(state: State<AppState>, revision: u32, index: u32) -> Outcome {
+    edit_at!(
+        state,
+        revision,
+        Command::ChangeLoopStart(engine::ChangeLoopStart { index })
+    )
+}
+
+#[tauri::command(async)]
+pub fn split(state: State<AppState>, revision: u32, at: u32, split_type: SplitType) -> Outcome {
+    edit_at!(
+        state,
+        revision,
+        Command::Split(engine::Split {
+            at,
+            split_type: split_type.into(),
+        })
+    )
+}

tauri/src/commands/selection.rs

@@ -0,0 +1,102 @@
+//! Changing what is selected.
+
+use gpx_engine::{self as engine, Action};
+use tauri::State;
+use uuid::Uuid;
+
+use crate::dto::*;
+use crate::state::{act, AppState};
+
+fn select_elements(
+    state: &AppState,
+    selection: Option<engine::Selection>,
+    mode: SelectMode,
+) -> Outcome {
+    match selection {
+        Some(selection) => act!(
+            state,
+            Action::Select {
+                selection,
+                mode: mode.into(),
+            }
+        ),
+        None => Outcome::failed("the ids are not UUIDs"),
+    }
+}
+
+fn to_file_ids(ids: Vec<Uuid>) -> Vec<engine::FileId> {
+    ids.into_iter().map(engine::FileId).collect()
+}
+
+#[tauri::command(async)]
+pub fn select(state: State<AppState>, file_ids: Vec<Uuid>, mode: SelectMode) -> Outcome {
+    let selection = engine::Selection::File {
+        file_ids: to_file_ids(file_ids).into_iter().collect(),
+    };
+    select_elements(&state, Some(selection), mode)
+}
+
+#[tauri::command(async)]
+pub fn select_all(state: State<AppState>) -> Outcome {
+    act!(state, Action::SelectAll)
+}
+
+#[tauri::command(async)]
+pub fn arrow_select(state: State<AppState>, down: bool, add: bool) -> Outcome {
+    act!(state, Action::ArrowSelect { down, add })
+}
+
+#[tauri::command(async)]
+pub fn select_tracks(
+    state: State<AppState>,
+    file_id: Uuid,
+    track_ids: Vec<Uuid>,
+    mode: SelectMode,
+) -> Outcome {
+    let selection = engine::Selection::Track {
+        file_id: engine::FileId(file_id),
+        trk_ids: track_ids.into_iter().map(engine::TrackId).collect(),
+    };
+    select_elements(&state, Some(selection), mode)
+}
+
+#[tauri::command(async)]
+pub fn select_segments(
+    state: State<AppState>,
+    file_id: Uuid,
+    track_id: Uuid,
+    segment_ids: Vec<Uuid>,
+    mode: SelectMode,
+) -> Outcome {
+    let selection = engine::Selection::TrackSegment {
+        file_id: engine::FileId(file_id),
+        trk_id: engine::TrackId(track_id),
+        trkseg_ids: segment_ids
+            .into_iter()
+            .map(engine::TrackSegmentId)
+            .collect(),
+    };
+    select_elements(&state, Some(selection), mode)
+}
+
+#[tauri::command(async)]
+pub fn select_waypoint_group(state: State<AppState>, file_id: Uuid, mode: SelectMode) -> Outcome {
+    let selection = engine::Selection::Waypoints {
+        file_id: engine::FileId(file_id),
+    };
+    select_elements(&state, Some(selection), mode)
+}
+
+#[tauri::command(async)]
+pub fn select_waypoints(
+    state: State<AppState>,
+    file_id: Uuid,
+    waypoint_ids: Vec<Uuid>,
+    mode: SelectMode,
+) -> Outcome {
+    let selection = engine::Selection::Waypoint {
+        file_id: engine::FileId(file_id),
+        wpt_ids: waypoint_ids.into_iter().map(engine::WaypointId).collect(),
+    };
+    select_elements(&state, Some(selection), mode)
+}

tauri/src/commands/statistics.rs

@@ -0,0 +1,135 @@
+//! The statistics of the selection and the anchors of the routing tool, as little-endian arrays
+//! (one per call, copies of the buffers of the engine). Optional ones start with a byte telling
+//! whether they are there.
+
+use tauri::State;
+
+use crate::dto::*;
+use crate::state::AppState;
+
+macro_rules! f64_getters {
+    ($($name:ident),*) => {$(
+        #[tauri::command(async)]
+        pub fn $name(state: State<AppState>) -> Bytes {
+            Bytes::new(state.read(|e| f64s(&e.statistics().$name)))
+        }
+    )*};
+}
+
+f64_getters!(
+    total_distance,
+    slope,
+    slope_segment_slope,
+    slope_segment_distance,
+    lng,
+    lat,
+    ele
+);
+
+macro_rules! optional_f64_getters {
+    ($($name:ident),*) => {$(
+        #[tauri::command(async)]
+        pub fn $name(state: State<AppState>) -> Bytes {
+            optional(state.read(|e| e.statistics().$name.as_deref().map(f64s)))
+        }
+    )*};
+}
+
+optional_f64_getters!(speed, hr, cad, atemp, power);
+
+/// Timestamps in milliseconds since the epoch (`NO_TIME` when missing), as `i64`.
+#[tauri::command(async)]
+pub fn timestamps(state: State<AppState>) -> Bytes {
+    optional(state.read(|e| e.statistics().time.as_deref().map(i64s)))
+}
+
+#[tauri::command(async)]
+pub fn selection_statistics(state: State<AppState>) -> GlobalStatistics {
+    state.read(|e| GlobalStatistics::new(&e.statistics().global))
+}
+
+#[tauri::command(async)]
+pub fn slice_statistics(
+    state: State<AppState>,
+    start: usize,
+    end: usize,
+) -> Option<GlobalStatistics> {
+    state.read(move |e| {
+        e.statistics()
+            .slice(start, end)
+            .map(|s| GlobalStatistics::new(&s))
+    })
+}
+
+macro_rules! intervals_getters {
+    ($starts:ident, $values:ident, $field:ident) => {
+        #[tauri::command(async)]
+        pub fn $starts(state: State<AppState>) -> Bytes {
+            Bytes::new(state.read(|e| u32s(&e.statistics().$field.starts)))
+        }
+
+        #[tauri::command(async)]
+        pub fn $values(state: State<AppState>) -> Bytes {
+            Bytes::new(state.read(|e| e.statistics().$field.values.clone()))
+        }
+    };
+}
+
+intervals_getters!(surface_starts, surface_values, surface);
+intervals_getters!(highway_starts, highway_values, highway);
+intervals_getters!(sac_scale_starts, sac_scale_values, sac_scale);
+intervals_getters!(mtb_scale_starts, mtb_scale_values, mtb_scale);
+
+/// The names of the categories, in the order of their codes. The lists only grow.
+#[tauri::command(async)]
+pub fn surfaces(state: State<AppState>) -> Vec<String> {
+    state.read(|e| e.categories().surface.names().to_vec())
+}
+
+#[tauri::command(async)]
+pub fn highways(state: State<AppState>) -> Vec<String> {
+    state.read(|e| e.categories().highway.names().to_vec())
+}
+
+#[tauri::command(async)]
+pub fn sac_scales(state: State<AppState>) -> Vec<String> {
+    state.read(|e| e.categories().sac_scale.names().to_vec())
+}
+
+#[tauri::command(async)]
+pub fn mtb_scales(state: State<AppState>) -> Vec<String> {
+    state.read(|e| e.categories().mtb_scale.names().to_vec())
+}
+
+// Routing buffers
+
+#[tauri::command(async)]
+pub fn anchor_indices(state: State<AppState>) -> Bytes {
+    Bytes::new(state.read(|e| u32s(&e.routing().anchor_indices)))
+}
+
+#[tauri::command(async)]
+pub fn anchor_zooms(state: State<AppState>) -> Bytes {
+    Bytes::new(state.read(|e| e.routing().anchor_zooms.clone()))
+}
+
+#[tauri::command(async)]
+pub fn segment_starts(state: State<AppState>) -> Bytes {
+    Bytes::new(state.read(|e| u32s(&e.routing().segment_starts)))
+}
+
+#[tauri::command(async)]
+pub fn segment_ids(state: State<AppState>) -> Vec<String> {
+    state.read(|e| {
+        e.routing()
+            .segment_ids
+            .iter()
+            .map(|id| id.0.to_string())
+            .collect()
+    })
+}
+
+#[tauri::command(async)]
+pub fn routing_revision(state: State<AppState>) -> u32 {
+    state.read(|e| e.routing().revision)
+}

tauri/src/commands/storage.rs

@@ -0,0 +1,46 @@
+//! Keeping the files and the settings.
+//!
+//! For now nothing is written: the files only live as long as the app, and so do the settings.
+//! The file system storage will go here.
+
+use serde::Serialize;
+use tauri::State;
+
+use crate::dto::Outcome;
+use crate::state::AppState;
+
+/// What opening the storage found.
+#[derive(Serialize)]
+pub struct StorageOpened {
+    settings: std::collections::BTreeMap<String, String>,
+    outcome: Outcome,
+}
+
+#[tauri::command(async)]
+pub fn open_storage(state: State<AppState>) -> StorageOpened {
+    StorageOpened {
+        settings: state.settings().clone(),
+        outcome: Outcome::failed_none(),
+    }
+}
+
+/// Resolves when what was changed has been written to the storage.
+#[tauri::command(async)]
+pub fn flush_storage() {}
+
+/// Reads the files again if they were written by someone else.
+#[tauri::command(async)]
+pub fn sync_storage() -> Outcome {
+    Outcome::failed_none()
+}
+
+/// Saves a setting, `value` being its JSON.
+#[tauri::command(async)]
+pub fn set_setting(state: State<AppState>, key: String, value: String) {
+    state.settings().insert(key, value);
+}
+
+#[tauri::command(async)]
+pub fn delete_setting(state: State<AppState>, key: String) {
+    state.settings().remove(&key);
+}

tauri/src/dto.rs

@@ -0,0 +1,578 @@
+//! What crosses to the frontend, as JSON: the same shapes as the objects of the WASM interface
+//! (`gpx-rs/wasm/src/ts.rs` holds their TypeScript types).
+
+use gpx_engine::{self as engine, FileId};
+use serde::{Deserialize, Serialize};
+use uuid::Uuid;
+
+/// Bytes that cross as they are: typed arrays (little-endian), GPX files.
+pub type Bytes = tauri::ipc::Response;
+
+pub fn f64s(values: &[f64]) -> Vec<u8> {
+    values.iter().flat_map(|v| v.to_le_bytes()).collect()
+}
+
+pub fn i64s(values: &[i64]) -> Vec<u8> {
+    values.iter().flat_map(|v| v.to_le_bytes()).collect()
+}
+
+pub fn u32s(values: &[u32]) -> Vec<u8> {
+    values.iter().flat_map(|v| v.to_le_bytes()).collect()
+}
+
+/// An array that can be absent: the first byte tells whether it is there, the array follows.
+pub fn optional(array: Option<Vec<u8>>) -> Bytes {
+    let mut bytes = vec![u8::from(array.is_some())];
+    bytes.extend(array.unwrap_or_default());
+    Bytes::new(bytes)
+}
+
+pub fn ids(items: &[FileId]) -> Vec<String> {
+    items.iter().map(|id| id.0.to_string()).collect()
+}
+
+// Outcome
+
+/// What a call that edits the files or changes the selection did.
+#[derive(Serialize)]
+#[serde(rename_all = "camelCase")]
+pub struct Outcome {
+    changed: bool,
+    order_changed: bool,
+    selection_changed: bool,
+    clipboard_changed: bool,
+    added: Vec<String>,
+    modified: Vec<String>,
+    removed: Vec<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    error: Option<String>,
+}
+
+impl Outcome {
+    pub fn new(outcome: &engine::Outcome, error: Option<String>) -> Self {
+        let diff = outcome.diff.clone().unwrap_or_default();
+        Self {
+            changed: outcome.changed,
+            order_changed: outcome.order_changed,
+            selection_changed: outcome.selection_changed,
+            clipboard_changed: outcome.clipboard_changed,
+            added: ids(&diff.added),
+            modified: ids(&diff.modified),
+            removed: ids(&diff.removed),
+            error,
+        }
+    }
+
+    /// The outcome of a call that did nothing and has nothing to say.
+    pub fn failed_none() -> Self {
+        Self::new(&engine::Outcome::default(), None)
+    }
+
+    /// What a call that does nothing returns.
+    pub fn failed(message: impl Into<String>) -> Self {
+        Self::new(&engine::Outcome::default(), Some(message.into()))
+    }
+}
+
+// Selection and clipboard
+
+#[derive(Serialize, Deserialize)]
+#[serde(
+    tag = "type",
+    rename_all = "camelCase",
+    rename_all_fields = "camelCase"
+)]
+pub enum Selection {
+    Empty,
+    File {
+        file_ids: Vec<Uuid>,
+    },
+    Track {
+        file_id: Uuid,
+        track_ids: Vec<Uuid>,
+    },
+    Segment {
+        file_id: Uuid,
+        track_id: Uuid,
+        segment_ids: Vec<Uuid>,
+    },
+    Waypoints {
+        file_id: Uuid,
+    },
+    Waypoint {
+        file_id: Uuid,
+        waypoint_ids: Vec<Uuid>,
+    },
+}
+
+impl From<&engine::Selection> for Selection {
+    fn from(selection: &engine::Selection) -> Self {
+        use engine::Selection as S;
+        match selection {
+            S::Empty => Self::Empty,
+            S::File { file_ids } => Self::File {
+                file_ids: file_ids.iter().map(|id| id.0).collect(),
+            },
+            S::Track { file_id, trk_ids } => Self::Track {
+                file_id: file_id.0,
+                track_ids: trk_ids.iter().map(|id| id.0).collect(),
+            },
+            S::TrackSegment {
+                file_id,
+                trk_id,
+                trkseg_ids,
+            } => Self::Segment {
+                file_id: file_id.0,
+                track_id: trk_id.0,
+                segment_ids: trkseg_ids.iter().map(|id| id.0).collect(),
+            },
+            S::Waypoints { file_id } => Self::Waypoints { file_id: file_id.0 },
+            S::Waypoint { file_id, wpt_ids } => Self::Waypoint {
+                file_id: file_id.0,
+                waypoint_ids: wpt_ids.iter().map(|id| id.0).collect(),
+            },
+        }
+    }
+}
+
+impl From<Selection> for engine::Selection {
+    fn from(selection: Selection) -> Self {
+        use engine::Selection as S;
+        match selection {
+            Selection::Empty => S::Empty,
+            Selection::File { file_ids } => S::File {
+                file_ids: file_ids.into_iter().map(FileId).collect(),
+            },
+            Selection::Track { file_id, track_ids } => S::Track {
+                file_id: FileId(file_id),
+                trk_ids: track_ids.into_iter().map(engine::TrackId).collect(),
+            },
+            Selection::Segment {
+                file_id,
+                track_id,
+                segment_ids,
+            } => S::TrackSegment {
+                file_id: FileId(file_id),
+                trk_id: engine::TrackId(track_id),
+                trkseg_ids: segment_ids
+                    .into_iter()
+                    .map(engine::TrackSegmentId)
+                    .collect(),
+            },
+            Selection::Waypoints { file_id } => S::Waypoints {
+                file_id: FileId(file_id),
+            },
+            Selection::Waypoint {
+                file_id,
+                waypoint_ids,
+            } => S::Waypoint {
+                file_id: FileId(file_id),
+                wpt_ids: waypoint_ids.into_iter().map(engine::WaypointId).collect(),
+            },
+        }
+    }
+}
+
+/// Where moved elements go. A negative index is the start, an infinite one the end (which JSON
+/// writes as `null`, so the frontend sends a very large number instead).
+#[derive(Deserialize)]
+#[serde(
+    tag = "type",
+    rename_all = "camelCase",
+    rename_all_fields = "camelCase"
+)]
+pub enum MoveTarget {
+    Files {
+        index: f64,
+    },
+    Tracks {
+        file_id: Uuid,
+        index: f64,
+    },
+    Segments {
+        file_id: Uuid,
+        track_id: Uuid,
+        index: f64,
+    },
+    Waypoints {
+        file_id: Uuid,
+        index: f64,
+    },
+}
+
+impl From<MoveTarget> for engine::MoveTarget {
+    fn from(target: MoveTarget) -> Self {
+        use engine::MoveTarget as T;
+        let index = |index: f64| index.max(0.0) as usize;
+        match target {
+            MoveTarget::Files { index: i } => T::Files { index: index(i) },
+            MoveTarget::Tracks { file_id, index: i } => T::Tracks {
+                file_id: FileId(file_id),
+                index: index(i),
+            },
+            MoveTarget::Segments {
+                file_id,
+                track_id,
+                index: i,
+            } => T::Segments {
+                file_id: FileId(file_id),
+                trk_id: engine::TrackId(track_id),
+                index: index(i),
+            },
+            MoveTarget::Waypoints { file_id, index: i } => T::Waypoints {
+                file_id: FileId(file_id),
+                index: index(i),
+            },
+        }
+    }
+}
+
+#[derive(Serialize)]
+pub struct Clipboard {
+    #[serde(rename = "type")]
+    kind: &'static str,
+    ids: Vec<String>,
+    cut: bool,
+}
+
+impl Clipboard {
+    pub fn new(clipboard: &engine::Clipboard) -> Self {
+        let strings = |ids: Vec<Uuid>| ids.iter().map(Uuid::to_string).collect();
+        let (kind, ids) = match clipboard.content.ids() {
+            engine::ClipboardIds::Files(ids) => {
+                ("files", strings(ids.into_iter().map(|id| id.0).collect()))
+            }
+            engine::ClipboardIds::Tracks(ids) => {
+                ("tracks", strings(ids.into_iter().map(|id| id.0).collect()))
+            }
+            engine::ClipboardIds::Segments(ids) => (
+                "segments",
+                strings(ids.into_iter().map(|id| id.0).collect()),
+            ),
+            engine::ClipboardIds::Waypoints(ids) => (
+                "waypoints",
+                strings(ids.into_iter().map(|id| id.0).collect()),
+            ),
+        };
+        Self {
+            kind,
+            ids,
+            cut: clipboard.cut,
+        }
+    }
+}
+
+// Files
+
+#[derive(Serialize)]
+#[serde(rename_all = "camelCase")]
+pub struct FileStructure {
+    id: String,
+    name: String,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    desc: Option<String>,
+    tracks: Vec<TrackNode>,
+    waypoints: Vec<WaypointNode>,
+    waypoints_rev: String,
+}
+
+#[derive(Serialize)]
+struct TrackNode {
+    id: String,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    name: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    desc: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    color: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    opacity: Option<f64>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    width: Option<f64>,
+    segments: Vec<SegmentNode>,
+}
+
+#[derive(Serialize)]
+struct SegmentNode {
+    id: String,
+    rev: String,
+    length: f64,
+}
+
+#[derive(Serialize)]
+struct WaypointNode {
+    id: String,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    name: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    sym: Option<String>,
+}
+
+impl FileStructure {
+    pub fn new(file: &engine::FileStructure) -> Self {
+        Self {
+            id: file.id.0.to_string(),
+            name: file.name.clone(),
+            desc: file.desc.clone(),
+            tracks: file
+                .tracks
+                .iter()
+                .map(|trk| TrackNode {
+                    id: trk.id.0.to_string(),
+                    name: trk.name.clone(),
+                    desc: trk.desc.clone(),
+                    color: trk.color.clone(),
+                    opacity: trk.opacity,
+                    width: trk.width,
+                    segments: trk
+                        .segments
+                        .iter()
+                        .map(|seg| SegmentNode {
+                            id: seg.id.0.to_string(),
+                            rev: seg.rev_id.0.to_string(),
+                            length: seg.len as f64,
+                        })
+                        .collect(),
+                })
+                .collect(),
+            waypoints: file
+                .waypoints
+                .iter()
+                .map(|wpt| WaypointNode {
+                    id: wpt.id.0.to_string(),
+                    name: wpt.name.clone(),
+                    sym: wpt.sym.clone(),
+                })
+                .collect(),
+            waypoints_rev: file.wpt_rev_id.0.to_string(),
+        }
+    }
+}
+
+#[derive(Serialize)]
+#[serde(rename_all = "camelCase")]
+pub struct GlobalStatistics {
+    total_distance: f64,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    moving_distance: Option<f64>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    total_time: Option<f64>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    moving_time: Option<f64>,
+    elevation_gain: f64,
+    elevation_loss: f64,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    start_time: Option<f64>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    end_time: Option<f64>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    total_speed: Option<f64>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    moving_speed: Option<f64>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    bounds: Option<Bounds>,
+}
+
+#[derive(Serialize)]
+struct Bounds {
+    west: f64,
+    south: f64,
+    east: f64,
+    north: f64,
+}
+
+impl GlobalStatistics {
+    pub fn new(stats: &engine::GlobalStatistics) -> Self {
+        let seconds = |ms: Option<i64>| ms.map(|ms| ms as f64 / 1000.0);
+        let (sw, ne) = (&stats.bounds.sw, &stats.bounds.ne);
+        Self {
+            total_distance: stats.total_distance,
+            moving_distance: stats.moving_distance,
+            total_time: seconds(stats.total_time),
+            moving_time: seconds(stats.moving_time),
+            elevation_gain: stats.elevation_gain,
+            elevation_loss: stats.elevation_loss,
+            start_time: stats.start_time.map(|t| t as f64),
+            end_time: stats.end_time.map(|t| t as f64),
+            total_speed: stats.total_speed(),
+            moving_speed: stats.moving_speed(),
+            bounds: (sw.lng <= ne.lng && sw.lat <= ne.lat).then_some(Bounds {
+                west: sw.lng,
+                south: sw.lat,
+                east: ne.lng,
+                north: ne.lat,
+            }),
+        }
+    }
+}
+
+#[derive(Serialize)]
+pub struct WaypointDetails {
+    id: String,
+    lng: f64,
+    lat: f64,
+    ele: f64,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    time: Option<f64>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    name: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    desc: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    cmt: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    sym: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    links: Option<Vec<Link>>,
+}
+
+#[derive(Serialize)]
+struct Link {
+    href: String,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    text: Option<String>,
+}
+
+impl WaypointDetails {
+    pub fn new(wpt: &engine::Waypoint) -> Self {
+        Self {
+            id: wpt.id.0.to_string(),
+            lng: wpt.coordinates.lng,
+            lat: wpt.coordinates.lat,
+            ele: wpt.ele,
+            time: wpt.time.map(|t| t as f64),
+            name: wpt.name.clone(),
+            desc: wpt.desc.clone(),
+            cmt: wpt.cmt.clone(),
+            sym: wpt.sym.clone(),
+            links: (!wpt.links.is_empty()).then(|| {
+                wpt.links
+                    .iter()
+                    .map(|link| Link {
+                        href: link.href.clone(),
+                        text: link.text.clone(),
+                    })
+                    .collect()
+            }),
+        }
+    }
+}
+
+#[derive(Serialize)]
+pub struct TrackpointDetails {
+    lng: f64,
+    lat: f64,
+    ele: f64,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    time: Option<f64>,
+}
+
+impl TrackpointDetails {
+    pub fn new(pt: &engine::Trackpoint) -> Self {
+        Self {
+            lng: pt.coordinates.lng,
+            lat: pt.coordinates.lat,
+            ele: pt.ele,
+            time: pt.time.map(|t| t as f64),
+        }
+    }
+}
+
+// Enumerations
+
+#[derive(Clone, Copy, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub enum SelectMode {
+    Replace,
+    Add,
+    Toggle,
+}
+
+impl From<SelectMode> for engine::SelectMode {
+    fn from(m: SelectMode) -> Self {
+        match m {
+            SelectMode::Replace => Self::Replace,
+            SelectMode::Add => Self::Add,
+            SelectMode::Toggle => Self::Toggle,
+        }
+    }
+}
+
+#[derive(Clone, Copy, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub enum MergeType {
+    Connect,
+    Group,
+}
+
+impl From<MergeType> for engine::MergeType {
+    fn from(t: MergeType) -> Self {
+        match t {
+            MergeType::Connect => Self::Connect,
+            MergeType::Group => Self::Group,
+        }
+    }
+}
+
+#[derive(Clone, Copy, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub enum SplitType {
+    Files,
+    Tracks,
+    Segments,
+}
+
+impl From<SplitType> for engine::SplitType {
+    fn from(t: SplitType) -> Self {
+        match t {
+            SplitType::Files => Self::Files,
+            SplitType::Tracks => Self::Tracks,
+            SplitType::Segments => Self::Segments,
+        }
+    }
+}
+
+#[derive(Clone, Copy, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub enum CleanType {
+    Inside,
+    Outside,
+}
+
+impl From<CleanType> for engine::CleanType {
+    fn from(t: CleanType) -> Self {
+        match t {
+            CleanType::Inside => Self::Inside,
+            CleanType::Outside => Self::Outside,
+        }
+    }
+}
+
+// Routing
+
+/// A category of the trackpoints of a route, as in `RouteCategory` of the engine.
+#[derive(Default, Deserialize)]
+pub struct RouteCategory {
+    pub starts: Vec<u32>,
+    pub values: Vec<u8>,
+    pub names: Vec<String>,
+}
+
+impl RouteCategory {
+    pub fn view(&self) -> engine::RouteCategory<'_> {
+        engine::RouteCategory {
+            starts: &self.starts,
+            values: &self.values,
+            names: &self.names,
+        }
+    }
+}
+
+#[derive(Default, Deserialize)]
+#[serde(rename_all = "camelCase", default)]
+pub struct RouteAttributes {
+    pub surface: RouteCategory,
+    pub highway: RouteCategory,
+    pub sac_scale: RouteCategory,
+    pub mtb_scale: RouteCategory,
+}

tauri/src/lib.rs

@@ -0,0 +1,125 @@
+//! The desktop shell of gpx.studio. The engine of the files (`gpx-rs/engine`) runs in this
+//! process, and the frontend talks to it through the commands of `commands`.
+
+mod commands;
+mod dto;
+mod state;
+
+use commands::*;
+
+#[cfg_attr(mobile, tauri::mobile_entry_point)]
+pub fn run() {
+    with_engine(tauri::Builder::default())
+        .run(tauri::generate_context!())
+        .expect("error while running gpx.studio");
+}
+
+/// Gives the builder the engine and the commands that reach it.
+fn with_engine<R: tauri::Runtime>(builder: tauri::Builder<R>) -> tauri::Builder<R> {
+    builder
+        .manage(state::AppState::default())
+        .invoke_handler(tauri::generate_handler![
+            // selection
+            selection::select,
+            selection::select_all,
+            selection::arrow_select,
+            selection::select_tracks,
+            selection::select_segments,
+            selection::select_waypoint_group,
+            selection::select_waypoints,
+            // files
+            files::new_file,
+            files::load_files,
+            files::duplicate,
+            files::delete,
+            files::delete_all,
+            files::reorder,
+            files::copy,
+            files::cut,
+            files::paste,
+            files::move_elements,
+            files::undo,
+            files::redo,
+            // edits and tools
+            edit::metadata,
+            edit::style,
+            edit::new_track,
+            edit::new_track_segment,
+            edit::new_waypoint,
+            edit::move_waypoint,
+            edit::delete_waypoint,
+            edit::update_waypoint,
+            edit::reverse,
+            edit::round_trip,
+            edit::crop,
+            edit::reduce,
+            edit::change_timestamps,
+            edit::create_artificial_timestamps,
+            edit::merge,
+            edit::extract,
+            edit::elevation,
+            edit::clean,
+            routing::route,
+            routing::insert_anchor,
+            routing::change_loop_start,
+            routing::split,
+            // queries
+            queries::file_order,
+            queries::file_structure,
+            queries::file_statistics,
+            queries::selection,
+            queries::clipboard,
+            queries::can_undo,
+            queries::can_redo,
+            queries::can_paste,
+            queries::waypoint,
+            queries::trackpoint,
+            queries::export_file,
+            queries::exportable_data,
+            queries::reduction_distances,
+            queries::segment_coordinates,
+            queries::waypoint_coordinates,
+            // statistics
+            statistics::total_distance,
+            statistics::slope,
+            statistics::slope_segment_slope,
+            statistics::slope_segment_distance,
+            statistics::lng,
+            statistics::lat,
+            statistics::ele,
+            statistics::speed,
+            statistics::hr,
+            statistics::cad,
+            statistics::atemp,
+            statistics::power,
+            statistics::timestamps,
+            statistics::selection_statistics,
+            statistics::slice_statistics,
+            statistics::surface_starts,
+            statistics::surface_values,
+            statistics::highway_starts,
+            statistics::highway_values,
+            statistics::sac_scale_starts,
+            statistics::sac_scale_values,
+            statistics::mtb_scale_starts,
+            statistics::mtb_scale_values,
+            statistics::surfaces,
+            statistics::highways,
+            statistics::sac_scales,
+            statistics::mtb_scales,
+            statistics::anchor_indices,
+            statistics::anchor_zooms,
+            statistics::segment_starts,
+            statistics::segment_ids,
+            statistics::routing_revision,
+            // storage
+            storage::open_storage,
+            storage::flush_storage,
+            storage::sync_storage,
+            storage::set_setting,
+            storage::delete_setting,
+        ])
+}
+
+#[cfg(test)]
+mod tests;

tauri/src/main.rs

@@ -0,0 +1,6 @@
+// Prevents an additional console window on Windows in release.
+#![cfg_attr(not(debug_assertions), windows_subsystem = "windows")]
+
+fn main() {
+    gpx_studio_desktop_lib::run()
+}

tauri/src/state.rs

@@ -0,0 +1,107 @@
+//! The state the commands share: the engine, and the settings of the frontend.
+//!
+//! The engine is not `Send` (it shares its data with `Rc`), so it lives on a thread of its own and
+//! the commands send it jobs: they are done one after the other, in the order they were sent.
+
+use std::collections::BTreeMap;
+use std::sync::mpsc::{self, Sender};
+use std::sync::{Mutex, MutexGuard};
+use std::thread;
+
+use gpx_engine::{Action, Engine};
+
+use crate::dto::Outcome;
+
+type Job = Box<dyn FnOnce(&mut Engine) + Send>;
+
+/// What the commands talk to. The engine is the same as in the browser (`gpx-rs`); here it lives in
+/// the process of the app, and the frontend reaches it through the commands only.
+pub struct AppState {
+    jobs: Mutex<Sender<Job>>,
+    /// The settings of the frontend, as JSON strings by key.
+    settings: Mutex<BTreeMap<String, String>>,
+}
+
+impl Default for AppState {
+    fn default() -> Self {
+        let (jobs, receiver) = mpsc::channel::<Job>();
+        thread::Builder::new()
+            .name("engine".into())
+            .spawn(move || {
+                let mut engine = Engine::default();
+                while let Ok(job) = receiver.recv() {
+                    job(&mut engine);
+                }
+            })
+            .expect("the engine thread could not be started");
+        Self {
+            jobs: Mutex::new(jobs),
+            settings: Mutex::default(),
+        }
+    }
+}
+
+impl AppState {
+    /// Runs `f` on the engine and waits for its result.
+    pub fn run<T: Send + 'static>(&self, f: impl FnOnce(&mut Engine) -> T + Send + 'static) -> T {
+        let (reply, result) = mpsc::channel();
+        let job: Job = Box::new(move |engine| {
+            let _ = reply.send(f(engine));
+        });
+        self.jobs
+            .lock()
+            .unwrap()
+            .send(job)
+            .expect("the engine thread stopped");
+        result.recv().expect("the engine thread stopped")
+    }
+
+    /// Reads from the engine.
+    pub fn read<T: Send + 'static>(&self, f: impl FnOnce(&Engine) -> T + Send + 'static) -> T {
+        self.run(move |engine| f(engine))
+    }
+
+    pub fn settings(&self) -> MutexGuard<'_, BTreeMap<String, String>> {
+        self.settings.lock().unwrap()
+    }
+}
+
+/// Executes an action and tells what it did, see `Outcome`.
+pub fn execute(engine: &mut Engine, action: Action) -> Outcome {
+    match engine.execute(action) {
+        Ok(outcome) => Outcome::new(&outcome, None),
+        Err(error) => Outcome::failed(error.to_string()),
+    }
+}
+
+/// Executes an action on the engine. The values the action uses are moved to the engine thread.
+macro_rules! act {
+    ($state:expr, $action:expr) => {
+        $state.run(move |engine| $crate::state::execute(engine, $action))
+    };
+}
+
+/// Executes a command (the command can borrow what it uses).
+macro_rules! edit {
+    ($state:expr, $command:expr) => {
+        act!($state, ::gpx_engine::Action::Edit($command))
+    };
+}
+
+/// Like `edit!`, but does nothing if the selection is not the one of `revision` anymore (the
+/// indices of the routing buffers only mean something for their revision).
+macro_rules! edit_at {
+    ($state:expr, $revision:expr, $command:expr) => {{
+        let revision = $revision;
+        $state.run(move |engine| {
+            if engine.routing().revision != revision {
+                return $crate::dto::Outcome::failed(
+                    "the selection changed since the routing buffers were read",
+                );
+            }
+            $crate::state::execute(engine, ::gpx_engine::Action::Edit($command))
+        })
+    }};
+}
+
+pub(crate) use {act, edit, edit_at};

tauri/src/tests.rs

@@ -0,0 +1,274 @@
+//! The commands, called the way the frontend calls them (through the IPC of Tauri), on the sample
+//! files of the engine.
+
+use serde_json::{json, Value};
+use tauri::test::{get_ipc_response, mock_builder, mock_context, noop_assets, INVOKE_KEY};
+use tauri::webview::InvokeRequest;
+use tauri::{ipc::CallbackFn, ipc::InvokeBody, ipc::InvokeResponseBody, WebviewWindow};
+
+struct App(WebviewWindow<tauri::test::MockRuntime>);
+
+impl App {
+    fn new() -> Self {
+        let app = crate::with_engine(mock_builder())
+            .build(mock_context(noop_assets()))
+            .unwrap();
+        let window = tauri::WebviewWindowBuilder::new(&app, "main", Default::default())
+            .build()
+            .unwrap();
+        // the app has to outlive its window
+        std::mem::forget(app);
+        Self(window)
+    }
+
+    fn request(
+        &self,
+        cmd: &str,
+        body: InvokeBody,
+        headers: tauri::http::HeaderMap,
+    ) -> InvokeResponseBody {
+        get_ipc_response(
+            &self.0,
+            InvokeRequest {
+                cmd: cmd.into(),
+                callback: CallbackFn(0),
+                error: CallbackFn(1),
+                url: "tauri://localhost".parse().unwrap(),
+                body,
+                headers,
+                invoke_key: INVOKE_KEY.to_string(),
+            },
+        )
+        .unwrap_or_else(|error| panic!("{cmd} failed: {error}"))
+    }
+
+    fn call(&self, cmd: &str, args: Value) -> Value {
+        match self.request(cmd, InvokeBody::Json(args), Default::default()) {
+            InvokeResponseBody::Json(json) => serde_json::from_str(&json).unwrap(),
+            InvokeResponseBody::Raw(_) => panic!("{cmd} returned bytes"),
+        }
+    }
+
+    fn bytes(&self, cmd: &str, args: Value) -> Vec<u8> {
+        match self.request(cmd, InvokeBody::Json(args), Default::default()) {
+            InvokeResponseBody::Raw(bytes) => bytes,
+            InvokeResponseBody::Json(_) => panic!("{cmd} returned JSON"),
+        }
+    }
+
+    fn load(&self, names: &[&str]) -> Value {
+        let mut data = vec![];
+        let mut lengths = vec![];
+        for name in names {
+            let file = std::fs::read(format!("../gpx-rs/engine/data/{name}.gpx")).unwrap();
+            lengths.push(file.len());
+            data.extend(file);
+        }
+        let header = |value: Value| value.to_string().replace('"', "%22").parse().unwrap();
+        let mut headers = tauri::http::HeaderMap::new();
+        headers.insert("lengths", header(json!(lengths)));
+        headers.insert("names", header(json!(names)));
+        match self.request("load_files", InvokeBody::Raw(data), headers) {
+            InvokeResponseBody::Json(json) => serde_json::from_str(&json).unwrap(),
+            InvokeResponseBody::Raw(_) => panic!("load_files returned bytes"),
+        }
+    }
+}
+
+fn f64s(bytes: &[u8]) -> Vec<f64> {
+    bytes
+        .chunks_exact(8)
+        .map(|chunk| f64::from_le_bytes(chunk.try_into().unwrap()))
+        .collect()
+}
+
+#[test]
+fn loads_files_and_describes_them() {
+    let app = App::new();
+    let outcome = app.load(&["simple", "with_tracks"]);
+    assert_eq!(outcome["changed"], true);
+    assert_eq!(outcome["added"].as_array().unwrap().len(), 2);
+    assert!(outcome.get("error").is_none());
+
+    let order = app.call("file_order", json!({}));
+    let first = order[0].as_str().unwrap();
+    assert_eq!(
+        app.call("selection", json!({})),
+        json!({ "type": "file", "fileIds": [first] })
+    );
+
+    let structure = app.call("file_structure", json!({ "fileId": first }));
+    assert_eq!(structure["name"], "simple");
+    let segment = &structure["tracks"][0]["segments"][0];
+    let length = segment["length"].as_f64().unwrap() as usize;
+    assert!(length > 0);
+
+    // coordinates are little-endian doubles, lng and lat for each trackpoint
+    let coordinates =
+        f64s(&app.bytes("segment_coordinates", json!({ "segmentId": segment["id"] })));
+    assert_eq!(coordinates.len(), 2 * length);
+
+    let statistics = app.call("file_statistics", json!({ "fileId": first }));
+    assert!(statistics["totalDistance"].as_f64().unwrap() > 0.0);
+    assert!(
+        statistics["bounds"]["west"].as_f64().unwrap()
+            <= statistics["bounds"]["east"].as_f64().unwrap()
+    );
+    assert_eq!(
+        app.call(
+            "file_structure",
+            json!({ "fileId": "00000000-0000-0000-0000-000000000000" })
+        ),
+        Value::Null
+    );
+}
+
+#[test]
+fn reads_the_statistics_of_the_selection() {
+    let app = App::new();
+    app.load(&["simple"]);
+    let distance = f64s(&app.bytes("total_distance", json!({})));
+    assert!(distance.len() > 1);
+    assert_eq!(f64s(&app.bytes("lng", json!({}))).len(), distance.len());
+    assert!(
+        app.call("selection_statistics", json!({}))["totalDistance"]
+            .as_f64()
+            .unwrap()
+            > 0.0
+    );
+    // optional arrays start with a byte telling whether they are there
+    let hr = app.bytes("hr", json!({}));
+    assert_eq!(hr[0], 0);
+    assert!(
+        app.call("slice_statistics", json!({ "start": 1, "end": 3 }))["totalDistance"].is_number()
+    );
+    assert_eq!(
+        app.call("slice_statistics", json!({ "start": 0, "end": 100000 })),
+        Value::Null
+    );
+
+    app.load(&["with_hr"]);
+    app.call("select_all", json!({}));
+    let hr = app.bytes("hr", json!({}));
+    assert_eq!(hr[0], 1);
+    assert_eq!((hr.len() - 1) % 8, 0);
+}
+
+#[test]
+fn edits_undoes_and_selects() {
+    let app = App::new();
+    let outcome = app.call(
+        "new_file",
+        json!({ "name": "route", "lng": 4.4, "lat": 50.8 }),
+    );
+    assert_eq!(outcome["changed"], true);
+    assert_eq!(app.call("can_undo", json!({})), true);
+
+    let id = app.call("file_order", json!({}))[0].clone();
+    let outcome = app.call("metadata", json!({ "name": "renamed", "desc": "" }));
+    assert_eq!(outcome["modified"], json!([id]));
+    assert_eq!(
+        app.call("file_structure", json!({ "fileId": id }))["name"],
+        "renamed"
+    );
+
+    let outcome = app.call("select", json!({ "fileIds": [], "mode": "replace" }));
+    assert_eq!(outcome["selectionChanged"], true);
+    assert_eq!(app.call("selection", json!({})), json!({ "type": "empty" }));
+    app.call("select", json!({ "fileIds": [id], "mode": "toggle" }));
+
+    app.call("undo", json!({}));
+    assert_eq!(
+        app.call("file_structure", json!({ "fileId": id }))["name"],
+        "route"
+    );
+    assert_eq!(app.call("can_redo", json!({})), true);
+    app.call("undo", json!({}));
+    assert_eq!(app.call("file_order", json!({})), json!([]));
+
+    // what cannot be done says why
+    let outcome = app.call("reverse", json!({}));
+    assert_eq!(outcome["changed"], false);
+    assert!(outcome["error"].is_string());
+}
+
+#[test]
+fn moves_and_clipboard() {
+    let app = App::new();
+    app.load(&["simple", "with_tracks"]);
+    let ids = app.call("file_order", json!({}));
+    app.call("select", json!({ "fileIds": [ids[0]], "mode": "replace" }));
+    app.call("copy", json!({}));
+    assert_eq!(
+        app.call("clipboard", json!({})),
+        json!({ "type": "files", "ids": [ids[0]], "cut": false })
+    );
+
+    let outcome = app.call(
+        "move_elements",
+        json!({
+            "what": { "type": "file", "fileIds": [ids[0]] },
+            "to": { "type": "files", "index": 9007199254740991u64 },
+        }),
+    );
+    assert_eq!(outcome["orderChanged"], true);
+    assert_eq!(app.call("file_order", json!({})), json!([ids[1], ids[0]]));
+}
+
+#[test]
+fn waypoints_exports_and_routing_revisions() {
+    let app = App::new();
+    app.call("new_file", json!({ "name": "file" }));
+    let outcome = app.call(
+        "new_waypoint",
+        json!({ "lng": 4.4, "lat": 50.8, "ele": 100, "name": "summit", "desc": "", "icon": "Summit", "link": "https://example.com" }),
+    );
+    assert_eq!(outcome["changed"], true);
+    let file = app.call("file_order", json!({}))[0].clone();
+    let waypoint =
+        app.call("file_structure", json!({ "fileId": file }))["waypoints"][0]["id"].clone();
+    let details = app.call(
+        "waypoint",
+        json!({ "fileId": file, "waypointId": waypoint }),
+    );
+    assert_eq!(details["name"], "summit");
+    assert_eq!(details["sym"], "Summit");
+    assert_eq!(details["links"][0]["href"], "https://example.com");
+
+    let exported = app.bytes(
+        "export_file",
+        json!({ "fileId": file, "time": true, "hr": true, "cad": true, "atemp": true, "power": true, "osm": true, "asRoute": false }),
+    );
+    assert_eq!(exported[0], 1);
+    assert!(String::from_utf8(exported[1..].to_vec())
+        .unwrap()
+        .contains("<wpt"));
+    assert_eq!(app.call("exportable_data", json!({ "fileIds": [file] })), 0);
+
+    let stale = app.call(
+        "route",
+        json!({
+            "revision": 12345, "start": 0, "end": 0,
+            "lng": [4.4], "lat": [50.8], "ele": [0],
+            "attributes": { "surface": { "starts": [0], "values": [0], "names": [] } },
+            "anchors": [],
+        }),
+    );
+    assert_eq!(stale["changed"], false);
+    assert!(stale["error"].as_str().unwrap().contains("routing buffers"));
+}
+
+#[test]
+fn keeps_settings_for_the_session() {
+    let app = App::new();
+    app.call(
+        "set_setting",
+        json!({ "key": "units", "value": "\"metric\"" }),
+    );
+    assert_eq!(
+        app.call("open_storage", json!({}))["settings"]["units"],
+        "\"metric\""
+    );
+    app.call("delete_setting", json!({ "key": "units" }));
+    assert_eq!(app.call("open_storage", json!({}))["settings"], json!({}));
+}

tauri/tauri.conf.json

@@ -0,0 +1,37 @@
+{
+    "$schema": "https://schema.tauri.app/config/2",
+    "productName": "gpx.studio",
+    "version": "0.1.0",
+    "identifier": "gpx.studio",
+    "build": {
+        "beforeDevCommand": "npm --prefix ../website run dev -- --port 4283",
+        "devUrl": "http://localhost:4283/app",
+        "beforeBuildCommand": "BASE_PATH='' npm --prefix ../website run build",
+        "frontendDist": "../website/build"
+    },
+    "app": {
+        "windows": [
+            {
+                "label": "main",
+                "title": "gpx.studio",
+                "url": "app.html",
+                "width": 1400,
+                "height": 900,
+                "minWidth": 800,
+                "minHeight": 600
+            }
+        ],
+        "security": { "csp": null }
+    },
+    "bundle": {
+        "active": true,
+        "targets": "all",
+        "icon": [
+            "icons/32x32.png",
+            "icons/128x128.png",
+            "icons/128x128@2x.png",
+            "icons/icon.icns",
+            "icons/icon.ico"
+        ]
+    }
+}

website/package-lock.json

@@ -31,6 +31,7 @@
                 "@sveltejs/kit": "^2.21.2",
                 "@sveltejs/vite-plugin-svelte": "^6.2.4",
                 "@tailwindcss/vite": "^4.1.8",
+                "@tauri-apps/api": "^2.12.3",
                 "@types/eslint": "^9.6.1",
                 "@types/events": "^3.0.3",
                 "@types/file-saver": "^2.0.7",
@@ -2635,6 +2636,17 @@
                 "vite": "^5.2.0 || ^6 || ^7 || ^8"
             }
         },
+        "node_modules/@tauri-apps/api": {
+            "version": "2.12.3",
+            "resolved": "https://registry.npmjs.org/@tauri-apps/api/-/api-2.12.3.tgz",
+            "integrity": "sha512-9s0PKw0p4r3kFq92jhpivYSp+cSht15o0gXpZxuQd0+dV9KCexEVkNaLELVoLdJWyoH4KlfQo5h3W2LIM8siJg==",
+            "dev": true,
+            "license": "Apache-2.0 OR MIT",
+            "funding": {
+                "type": "opencollective",
+                "url": "https://opencollective.com/tauri"
+            }
+        },
         "node_modules/@types/cookie": {
             "version": "0.6.0",
             "dev": true,

website/package.json

@@ -24,6 +24,7 @@
         "@sveltejs/kit": "^2.21.2",
         "@sveltejs/vite-plugin-svelte": "^6.2.4",
         "@tailwindcss/vite": "^4.1.8",
+        "@tauri-apps/api": "^2.12.3",
         "@types/eslint": "^9.6.1",
         "@types/events": "^3.0.3",
         "@types/file-saver": "^2.0.7",

website/src/lib/components/elevation-profile/elevation-profile.ts

@@ -400,10 +400,13 @@ export class ElevationProfile {
                     } else if (startIndex !== endIndex) {
                         const start = Math.min(startIndex, endIndex);
                         const end = Math.max(startIndex, endIndex);
-                        const global = get(this._statistics).slice(start, end);
+                        get(this._statistics)
+                            .slice(start, end)
+                            .then((global) => {
                                 if (global) {
                                     this._slicedStatistics.set({ global, start, end });
                                 }
+                            });
                     }
                 }
             }

website/src/lib/components/export/Export.svelte

@@ -54,9 +54,21 @@
         return [];
     });
     // the data that none of them has is not offered
-    let hide: Record<keyof ExportOptions, boolean> = $derived.by(() => {
-        const available = engine.exportableData(fileIds);
-        return {
+    let hide: Record<keyof ExportOptions, boolean> = $state({
+        time: false,
+        hr: false,
+        cad: false,
+        atemp: false,
+        power: false,
+        osm: false,
+        asRoute: false,
+    });
+    $effect(() => {
+        const ids = fileIds;
+        engine.exportableData(ids).then((available) => {
+            // the files may have changed since
+            if (ids === fileIds) {
+                hide = {
                     time: !available.time,
                     hr: !available.hr,
                     cad: !available.cad,
@@ -66,6 +78,8 @@
                     // always possible
                     asRoute: false,
                 };
+            }
+        });
     });
 
     $effect(() => {

website/src/lib/components/export/utils.svelte.ts

@@ -31,11 +31,15 @@ export function allFileIds(): string[] {
 }
 
 async function exportFiles(fileIds: string[], options: ExportOptions) {
-    const files = fileIds.flatMap((fileId) => {
-        const gpx = engine.exportFile(fileId, options);
+    const files = (
+        await Promise.all(
+            fileIds.map(async (fileId) => {
+                const gpx = await engine.exportFile(fileId, options);
                 const name = get(engine.files).get(fileId);
                 return gpx === undefined || !name ? [] : [{ name: get(name).structure.name, gpx }];
-    });
+            })
+        )
+    ).flat();
 
     if (files.length === 1) {
         const blob = new Blob([files[0].gpx], { type: 'application/gpx+xml' });

website/src/lib/components/file-list/FileListNodeLabel.svelte

@@ -152,9 +152,9 @@
                         engine.selectNode(node, 'toggle');
                     }
                 }}
-                onmouseenter={() => {
+                onmouseenter={async () => {
                     if (node.type === 'waypoint' && !isHidden(fileState, node.waypointId)) {
-                        const waypoint = engine.waypoint(node.fileId, node.waypointId);
+                        const waypoint = await engine.waypoint(node.fileId, node.waypointId);
                         if (waypoint) {
                             waypointPopup?.setItem({
                                 item: waypoint,

website/src/lib/components/map/gpx-layer/gpx-layer.ts

@@ -393,13 +393,15 @@ export class GPXLayer {
         mapCursor.notify(MapCursorState.LAYER_HOVER, false);
     }
 
-    layerOnMouseMove(e: any) {
+    async layerOnMouseMove(e: any) {
         if (e.originalEvent.shiftKey) {
             const { segmentId } = e.features[0].properties;
             const lngLat = { lng: e.lngLat.lng, lat: e.lngLat.lat };
-            const index = closestPointIndex(engine.segmentCoordinates(segmentId), lngLat);
+            const index = closestPointIndex(await engine.segmentCoordinates(segmentId), lngLat);
             const trackpoint =
-                index === undefined ? undefined : engine.trackpoint(this.fileId, segmentId, index);
+                index === undefined
+                    ? undefined
+                    : await engine.trackpoint(this.fileId, segmentId, index);
             if (trackpoint) {
                 trackpointPopup?.setItem({
                     item: trackpoint,
@@ -469,8 +471,8 @@ export class GPXLayer {
         mapCursor.notify(MapCursorState.WAYPOINT_HOVER, true);
     }
 
-    showWaypointPopup(waypointId: string) {
-        const waypoint = engine.waypoint(this.fileId, waypointId);
+    async showWaypointPopup(waypointId: string) {
+        const waypoint = await engine.waypoint(this.fileId, waypointId);
         if (waypoint) {
             waypointPopup?.setItem({ item: waypoint, kind: 'waypoint', fileId: this.fileId });
         }

website/src/lib/components/toolbar/tools/reduce/Reduce.svelte

@@ -30,9 +30,14 @@
     let reducedLayer = new ReducedLayer();
 
     // read again only when the selection or the files change, not with the tolerance
-    let distances = $derived.by(() => {
-        void $statistics;
-        return engine.reductionDistances();
+    let distances = $state<Float64Array>(new Float64Array());
+    $effect(() => {
+        const current = $statistics;
+        engine.reductionDistances().then((values) => {
+            if (current === $statistics) {
+                distances = values;
+            }
+        });
     });
 
     $effect(() => {

website/src/lib/components/toolbar/tools/scissors/Scissors.svelte

@@ -61,8 +61,12 @@
     function updateSlicedStatistics([startStep, endStep]: number[]) {
         if (validSelection && (startStep !== 0 || endStep !== steps)) {
             const [start, end] = [toIndex(startStep), toIndex(endStep)];
-            const global = $statistics.slice(start, end);
+            $statistics.slice(start, end).then((global) => {
+                // the slider may have moved since
+                if (validSelection) {
                     slicedStatistics.set(global && { global, start, end });
+                }
+            });
         } else {
             slicedStatistics.set(undefined);
         }

website/src/lib/components/toolbar/tools/waypoint/waypoint.ts

@@ -92,8 +92,8 @@ export class WaypointSelection {
         }
 
         // read again each time the file changes
-        const read = () => {
-            const waypoint = engine.waypoint(target.fileId, target.id);
+        const read = async () => {
+            const waypoint = await engine.waypoint(target.fileId, target.id);
             this._selection.set(waypoint ? { ...target, waypoint } : undefined);
         };
         const file = get(engine.files).get(target.fileId);

website/src/lib/data/example/example.test.ts

@@ -5,8 +5,8 @@ import { exampleData } from '$lib/data/example/example-data';
 import { exampleStatistics } from '$lib/data/example';
 
 describe('exampleStatistics', () => {
-    it('has the statistics of the whole example for the whole range', () => {
-        const whole = exampleStatistics.slice(0, exampleStatistics.length - 1);
+    it('has the statistics of the whole example for the whole range', async () => {
+        const whole = await exampleStatistics.slice(0, exampleStatistics.length - 1);
         const global = exampleStatistics.global;
         assert.ok(whole);
         for (const key of [
@@ -25,17 +25,17 @@ describe('exampleStatistics', () => {
         }
     });
 
-    it('has no speed for a range that does not last', () => {
-        const point = exampleStatistics.slice(20, 20);
+    it('has no speed for a range that does not last', async () => {
+        const point = await exampleStatistics.slice(20, 20);
         assert.equal(point?.totalTime, 0);
         assert.equal(point?.totalSpeed, undefined);
         assert.equal(point?.movingSpeed, undefined);
     });
 
-    it('has nothing for ranges that are not in the example', () => {
-        assert.equal(exampleStatistics.slice(5, 500), undefined);
-        assert.equal(exampleStatistics.slice(-1, 3), undefined);
-        assert.equal(exampleStatistics.slice(10, 5), undefined);
+    it('has nothing for ranges that are not in the example', async () => {
+        assert.equal(await exampleStatistics.slice(5, 500), undefined);
+        assert.equal(await exampleStatistics.slice(-1, 3), undefined);
+        assert.equal(await exampleStatistics.slice(10, 5), undefined);
     });
 
     it(

website/src/lib/data/example/index.ts

@@ -20,7 +20,7 @@ const cumulative = {
 };
 
 /** The statistics of the trackpoints from `start` to `end` (both included), as the engine does. */
-function slice(start: number, end: number): GlobalStatistics | undefined {
+async function slice(start: number, end: number): Promise<GlobalStatistics | undefined> {
     if (!(start >= 0 && start <= end && end < length)) {
         return undefined;
     }

website/src/lib/engine/backend/index.ts

@@ -0,0 +1,18 @@
+import type { Backend } from './types';
+
+export type { Backend } from './types';
+
+/** Whether the page runs in the desktop app, which has the engine in its own process. */
+function inDesktopApp() {
+    return typeof window !== 'undefined' && '__TAURI_INTERNALS__' in window;
+}
+
+/**
+ * Starts the engine of the files: the one of the desktop app when the page runs in it, the
+ * WebAssembly module otherwise.
+ */
+export async function loadBackend(): Promise<Backend> {
+    return inDesktopApp()
+        ? (await import('./tauri')).createTauriBackend()
+        : (await import('./wasm')).createWasmBackend();
+}

website/src/lib/engine/backend/tauri.ts

@@ -0,0 +1,217 @@
+import { invoke } from '@tauri-apps/api/core';
+import type { RouteAttributes, StorageOpened } from 'gpx-rs';
+import type { Backend } from './types';
+
+/** An array that a command returns as its bytes. */
+const array = async <T>(
+    command: string,
+    type: { new (buffer: ArrayBuffer): T },
+    args?: Record<string, unknown>
+) => new type(await invoke<ArrayBuffer>(command, args));
+
+/** Like `array`, for the arrays that can be absent: the first byte tells whether they are there. */
+const optionalArray = async <T>(
+    command: string,
+    type: { new (buffer: ArrayBuffer): T },
+    args?: Record<string, unknown>
+) => {
+    const bytes = await invoke<ArrayBuffer>(command, args);
+    return new Uint8Array(bytes)[0] === 1 ? new type(bytes.slice(1)) : undefined;
+};
+
+const category = (c?: RouteAttributes['surface']) =>
+    c && { starts: Array.from(c.starts), values: Array.from(c.values), names: c.names };
+
+/**
+ * The engine in the Rust process of the desktop app, reached through its commands (see
+ * `tauri/src/commands`). Typed arrays are returned as bytes, little-endian.
+ */
+export async function createTauriBackend(): Promise<Backend> {
+    const f64 = (command: string, args?: Record<string, unknown>) =>
+        array(command, Float64Array, args);
+    const u32 = (command: string) => array(command, Uint32Array);
+    const u8 = (command: string) => array(command, Uint8Array);
+    const f64Optional = (command: string) => optionalArray(command, Float64Array);
+
+    return {
+        select: (fileIds, mode) => invoke('select', { fileIds, mode }),
+        select_all: () => invoke('select_all'),
+        arrow_select: (down, add) => invoke('arrow_select', { down, add }),
+        select_tracks: (fileId, trackIds, mode) =>
+            invoke('select_tracks', { fileId, trackIds, mode }),
+        select_segments: (fileId, trackId, segmentIds, mode) =>
+            invoke('select_segments', { fileId, trackId, segmentIds, mode }),
+        select_waypoint_group: (fileId, mode) => invoke('select_waypoint_group', { fileId, mode }),
+        select_waypoints: (fileId, waypointIds, mode) =>
+            invoke('select_waypoints', { fileId, waypointIds, mode }),
+
+        undo: () => invoke('undo'),
+        redo: () => invoke('redo'),
+        copy: () => invoke('copy'),
+        cut: () => invoke('cut'),
+        paste: () => invoke('paste'),
+
+        new_file: (name, lng, lat, ele) => invoke('new_file', { name, lng, lat, ele }),
+        load_files: (files) => {
+            const data = new Uint8Array(files.reduce((sum, file) => sum + file.data.length, 0));
+            let offset = 0;
+            for (const file of files) {
+                data.set(file.data, offset);
+                offset += file.data.length;
+            }
+            // headers are ASCII
+            const header = (value: unknown) => encodeURIComponent(JSON.stringify(value));
+            return invoke('load_files', data, {
+                headers: {
+                    lengths: header(files.map((file) => file.data.length)),
+                    names: header(files.map((file) => file.name)),
+                },
+            });
+        },
+        duplicate: () => invoke('duplicate'),
+        delete: (wholeFiles) => invoke('delete', { wholeFiles }),
+        delete_all: () => invoke('delete_all'),
+        reorder: (fileIds, index) => invoke('reorder', { fileIds, index }),
+        // an infinite index is the end of the list, which JSON cannot tell
+        move_elements: (what, to) =>
+            invoke('move_elements', {
+                what,
+                to: { ...to, index: Math.min(to.index, Number.MAX_SAFE_INTEGER) },
+            }),
+        metadata: (name, desc) => invoke('metadata', { name, desc }),
+        style: (color, opacity, width) => invoke('style', { color, opacity, width }),
+        new_track: () => invoke('new_track'),
+        new_track_segment: () => invoke('new_track_segment'),
+
+        new_waypoint: (lng, lat, ele, name, desc, icon, link) =>
+            invoke('new_waypoint', { lng, lat, ele, name, desc, icon, link }),
+        update_waypoint: (fileId, waypointId, lng, lat, ele, name, desc, icon, link) =>
+            invoke('update_waypoint', {
+                fileId,
+                waypointId,
+                lng,
+                lat,
+                ele,
+                name,
+                desc,
+                icon,
+                link,
+            }),
+        move_waypoint: (fileId, waypointId, lng, lat, ele) =>
+            invoke('move_waypoint', { fileId, waypointId, lng, lat, ele }),
+        delete_waypoint: (fileId, waypointId) => invoke('delete_waypoint', { fileId, waypointId }),
+
+        reverse: () => invoke('reverse'),
+        extract: () => invoke('extract'),
+        round_trip: () => invoke('round_trip'),
+        elevation: (ele) => invoke('elevation', { ele: Array.from(ele) }),
+        change_timestamps: (startTime, speed, ratio) =>
+            invoke('change_timestamps', { startTime, speed, ratio }),
+        create_artificial_timestamps: (startTime, totalTime) =>
+            invoke('create_artificial_timestamps', { startTime, totalTime }),
+        clean: (west, south, east, north, inside, trkpt, wpt) =>
+            invoke('clean', {
+                west,
+                south,
+                east,
+                north,
+                cleanType: inside ? 'inside' : 'outside',
+                trkpt,
+                wpt,
+            }),
+        merge: (mergeType, removeGaps) => invoke('merge', { mergeType, removeGaps }),
+        reduce: (tolerance) => invoke('reduce', { tolerance }),
+        crop: (start, end) => invoke('crop', { start, end }),
+        split: (revision, at, splitType) => invoke('split', { revision, at, splitType }),
+        route: (revision, start, end, lng, lat, ele, attributes, anchors) =>
+            invoke('route', {
+                revision,
+                start,
+                end,
+                lng: Array.from(lng),
+                lat: Array.from(lat),
+                ele: Array.from(ele),
+                attributes: {
+                    surface: category(attributes.surface),
+                    highway: category(attributes.highway),
+                    sacScale: category(attributes.sacScale),
+                    mtbScale: category(attributes.mtbScale),
+                },
+                anchors: Array.from(anchors),
+            }),
+        insert_anchor: (revision, lng, lat) => invoke('insert_anchor', { revision, lng, lat }),
+        change_loop_start: (revision, index) => invoke('change_loop_start', { revision, index }),
+
+        can_undo: () => invoke('can_undo'),
+        can_redo: () => invoke('can_redo'),
+        can_paste: () => invoke('can_paste'),
+        clipboard: async () => (await invoke('clipboard')) ?? undefined,
+        selection: () => invoke('selection'),
+        file_order: () => invoke('file_order'),
+        file_structure: async (fileId) => (await invoke('file_structure', { fileId })) ?? undefined,
+        file_statistics: async (fileId) =>
+            (await invoke('file_statistics', { fileId })) ?? undefined,
+        waypoint: async (fileId, waypointId) =>
+            (await invoke('waypoint', { fileId, waypointId })) ?? undefined,
+        trackpoint: async (fileId, segmentId, index) =>
+            (await invoke('trackpoint', { fileId, segmentId, index })) ?? undefined,
+        export_file: async (fileId, time, hr, cad, atemp, power, osm, asRoute) => {
+            const file = await optionalArray('export_file', Uint8Array, {
+                fileId,
+                time,
+                hr,
+                cad,
+                atemp,
+                power,
+                osm,
+                asRoute,
+            });
+            return file as Uint8Array<ArrayBuffer> | undefined;
+        },
+        exportable_data: (fileIds) => invoke('exportable_data', { fileIds }),
+        reduction_distances: () => f64('reduction_distances'),
+        segment_coordinates: (segmentId) => f64('segment_coordinates', { segmentId }),
+        waypoint_coordinates: (fileId) => f64('waypoint_coordinates', { fileId }),
+
+        selection_statistics: () => invoke('selection_statistics'),
+        slice_statistics: async (start, end) =>
+            (await invoke('slice_statistics', { start, end })) ?? undefined,
+        total_distance: () => f64('total_distance'),
+        slope: () => f64('slope'),
+        lng: () => f64('lng'),
+        lat: () => f64('lat'),
+        ele: () => f64('ele'),
+        timestamps: () => optionalArray('timestamps', BigInt64Array),
+        speed: () => f64Optional('speed'),
+        hr: () => f64Optional('hr'),
+        cad: () => f64Optional('cad'),
+        atemp: () => f64Optional('atemp'),
+        power: () => f64Optional('power'),
+        slope_segment_slope: () => f64('slope_segment_slope'),
+        slope_segment_distance: () => f64('slope_segment_distance'),
+        surface_starts: () => u32('surface_starts'),
+        surface_values: () => u8('surface_values'),
+        surfaces: () => invoke('surfaces'),
+        highway_starts: () => u32('highway_starts'),
+        highway_values: () => u8('highway_values'),
+        highways: () => invoke('highways'),
+        sac_scale_starts: () => u32('sac_scale_starts'),
+        sac_scale_values: () => u8('sac_scale_values'),
+        sac_scales: () => invoke('sac_scales'),
+        mtb_scale_starts: () => u32('mtb_scale_starts'),
+        mtb_scale_values: () => u8('mtb_scale_values'),
+        mtb_scales: () => invoke('mtb_scales'),
+        anchor_indices: () => u32('anchor_indices'),
+        anchor_zooms: () => u8('anchor_zooms'),
+        segment_starts: () => u32('segment_starts'),
+        segment_ids: () => invoke('segment_ids'),
+        routing_revision: () => invoke('routing_revision'),
+
+        importsLegacyData: false,
+        open_storage: () => invoke<StorageOpened>('open_storage'),
+        flush_storage: () => invoke('flush_storage'),
+        sync_storage: () => invoke('sync_storage'),
+        set_setting: (key, value) => invoke('set_setting', { key, value }),
+        delete_setting: (key) => invoke('delete_setting', { key }),
+    };
+}

website/src/lib/engine/backend/types.ts

@@ -0,0 +1,211 @@
+import type {
+    Clipboard,
+    FileStructure,
+    GlobalStatistics,
+    MoveTarget,
+    Outcome,
+    RouteAttributes,
+    Selection,
+    StorageOpened,
+    TrackpointDetails,
+    WaypointDetails,
+} from 'gpx-rs';
+import type { MergeType, SelectMode, SplitType } from '../types';
+
+/**
+ * What the facade needs of the engine of the files, wherever it runs: the WASM module in the
+ * browser (`wasm.ts`), or the Rust process of the desktop app, through its commands (`tauri.ts`).
+ * Both give the same results: see `gpx-rs/wasm` for what each function does.
+ *
+ * Everything is asynchronous, because the desktop app is reached through messages. Ids are
+ * hyphenated UUID strings, the arrays of numbers are typed arrays, and what the functions that
+ * edit the files or change the selection return is an `Outcome`.
+ */
+export interface Backend {
+    // Selection
+    select(fileIds: string[], mode: SelectMode): Promise<Outcome>;
+    select_all(): Promise<Outcome>;
+    arrow_select(down: boolean, add: boolean): Promise<Outcome>;
+    select_tracks(fileId: string, trackIds: string[], mode: SelectMode): Promise<Outcome>;
+    select_segments(
+        fileId: string,
+        trackId: string,
+        segmentIds: string[],
+        mode: SelectMode
+    ): Promise<Outcome>;
+    select_waypoint_group(fileId: string, mode: SelectMode): Promise<Outcome>;
+    select_waypoints(fileId: string, waypointIds: string[], mode: SelectMode): Promise<Outcome>;
+
+    // History and clipboard
+    undo(): Promise<Outcome>;
+    redo(): Promise<Outcome>;
+    copy(): Promise<Outcome>;
+    cut(): Promise<Outcome>;
+    paste(): Promise<Outcome>;
+
+    // Files
+    new_file(name: string, lng?: number, lat?: number, ele?: number): Promise<Outcome>;
+    load_files(files: { data: Uint8Array; name: string }[]): Promise<Outcome>;
+    duplicate(): Promise<Outcome>;
+    delete(wholeFiles: boolean): Promise<Outcome>;
+    delete_all(): Promise<Outcome>;
+    reorder(fileIds: string[], index: number): Promise<Outcome>;
+    move_elements(what: Selection, to: MoveTarget): Promise<Outcome>;
+    metadata(name: string, desc: string): Promise<Outcome>;
+    style(color?: string, opacity?: number, width?: number): Promise<Outcome>;
+    new_track(): Promise<Outcome>;
+    new_track_segment(): Promise<Outcome>;
+
+    // Waypoints
+    new_waypoint(
+        lng: number,
+        lat: number,
+        ele: number,
+        name: string,
+        desc: string,
+        icon: string,
+        link: string
+    ): Promise<Outcome>;
+    update_waypoint(
+        fileId: string,
+        waypointId: string,
+        lng: number,
+        lat: number,
+        ele: number,
+        name: string,
+        desc: string,
+        icon: string,
+        link: string
+    ): Promise<Outcome>;
+    move_waypoint(
+        fileId: string,
+        waypointId: string,
+        lng: number,
+        lat: number,
+        ele: number
+    ): Promise<Outcome>;
+    delete_waypoint(fileId: string, waypointId: string): Promise<Outcome>;
+
+    // Tools
+    reverse(): Promise<Outcome>;
+    extract(): Promise<Outcome>;
+    round_trip(): Promise<Outcome>;
+    elevation(ele: Float64Array): Promise<Outcome>;
+    change_timestamps(startTime: number, speed: number, ratio: number): Promise<Outcome>;
+    create_artificial_timestamps(startTime: number, totalTime: number): Promise<Outcome>;
+    clean(
+        west: number,
+        south: number,
+        east: number,
+        north: number,
+        inside: boolean,
+        trackpoints: boolean,
+        waypoints: boolean
+    ): Promise<Outcome>;
+    merge(type: MergeType, removeGaps: boolean): Promise<Outcome>;
+    reduce(tolerance: number): Promise<Outcome>;
+    crop(start: number, end: number): Promise<Outcome>;
+    split(revision: number, at: number, type: SplitType): Promise<Outcome>;
+    route(
+        revision: number,
+        start: number,
+        end: number,
+        lng: Float64Array,
+        lat: Float64Array,
+        ele: Float64Array,
+        attributes: RouteAttributes,
+        anchors: Uint32Array
+    ): Promise<Outcome>;
+    insert_anchor(revision: number, lng: number, lat: number): Promise<Outcome>;
+    change_loop_start(revision: number, index: number): Promise<Outcome>;
+
+    // The files and the selection
+    can_undo(): Promise<boolean>;
+    can_redo(): Promise<boolean>;
+    can_paste(): Promise<boolean>;
+    clipboard(): Promise<Clipboard | undefined>;
+    selection(): Promise<Selection>;
+    file_order(): Promise<string[]>;
+    file_structure(fileId: string): Promise<FileStructure | undefined>;
+    file_statistics(fileId: string): Promise<GlobalStatistics | undefined>;
+    waypoint(fileId: string, waypointId: string): Promise<WaypointDetails | undefined>;
+    trackpoint(
+        fileId: string,
+        segmentId: string,
+        index: number
+    ): Promise<TrackpointDetails | undefined>;
+    /** A file as GPX (UTF-8 bytes), `undefined` if it does not exist. */
+    export_file(
+        fileId: string,
+        time: boolean,
+        hr: boolean,
+        cad: boolean,
+        atemp: boolean,
+        power: boolean,
+        osm: boolean,
+        asRoute: boolean
+    ): Promise<Uint8Array<ArrayBuffer> | undefined>;
+    exportable_data(fileIds: string[]): Promise<number>;
+    reduction_distances(): Promise<Float64Array>;
+    segment_coordinates(segmentId: string): Promise<Float64Array>;
+    waypoint_coordinates(fileId: string): Promise<Float64Array>;
+
+    // The statistics of the selection
+    selection_statistics(): Promise<GlobalStatistics | undefined>;
+    slice_statistics(start: number, end: number): Promise<GlobalStatistics | undefined>;
+    total_distance(): Promise<Float64Array>;
+    slope(): Promise<Float64Array>;
+    lng(): Promise<Float64Array>;
+    lat(): Promise<Float64Array>;
+    ele(): Promise<Float64Array>;
+    timestamps(): Promise<BigInt64Array | undefined>;
+    speed(): Promise<Float64Array | undefined>;
+    hr(): Promise<Float64Array | undefined>;
+    cad(): Promise<Float64Array | undefined>;
+    atemp(): Promise<Float64Array | undefined>;
+    power(): Promise<Float64Array | undefined>;
+    slope_segment_slope(): Promise<Float64Array>;
+    slope_segment_distance(): Promise<Float64Array>;
+    surface_starts(): Promise<Uint32Array>;
+    surface_values(): Promise<Uint8Array>;
+    surfaces(): Promise<string[]>;
+    highway_starts(): Promise<Uint32Array>;
+    highway_values(): Promise<Uint8Array>;
+    highways(): Promise<string[]>;
+    sac_scale_starts(): Promise<Uint32Array>;
+    sac_scale_values(): Promise<Uint8Array>;
+    sac_scales(): Promise<string[]>;
+    mtb_scale_starts(): Promise<Uint32Array>;
+    mtb_scale_values(): Promise<Uint8Array>;
+    mtb_scales(): Promise<string[]>;
+    anchor_indices(): Promise<Uint32Array>;
+    anchor_zooms(): Promise<Uint8Array>;
+    segment_starts(): Promise<Uint32Array>;
+    segment_ids(): Promise<string[]>;
+    routing_revision(): Promise<number>;
+
+    // Storage
+    /**
+     * Whether the files that the previous versions of the app kept in the browser can be imported
+     * (they are in the IndexedDB of the browser).
+     */
+    readonly importsLegacyData: boolean;
+    /**
+     * Opens the storage: the files that it holds are put in the engine, and the changes of the
+     * files are kept from then on. `onSaved` is called after the files were written, `onBehind`
+     * when a write was refused because another window wrote since (call `sync_storage` then), and
+     * `onNewer` when what is stored comes from a newer version of the app.
+     */
+    open_storage(
+        name: string,
+        onSaved: () => void,
+        onBehind: () => void,
+        onNewer: () => void
+    ): Promise<StorageOpened>;
+    /** Resolves when what was changed has been written to the storage. */
+    flush_storage(): Promise<void>;
+    /** Reads the files again if another window wrote them since, and tells what changed. */
+    sync_storage(): Promise<Outcome>;
+    set_setting(key: string, json: string): Promise<void>;
+    delete_setting(key: string): Promise<void>;
+}

website/src/lib/engine/backend/wasm.ts

@@ -0,0 +1,172 @@
+import type { Backend } from './types';
+import type { MergeType, SelectMode, SplitType } from '../types';
+
+type Wasm = typeof import('gpx-rs');
+
+/** A call of the module, which is synchronous, as an asynchronous one. */
+const lift =
+    <A extends unknown[], R>(f: (...args: A) => R) =>
+    async (...args: A): Promise<R> =>
+        f(...args);
+
+/** Hyphenated UUID strings to the concatenated 16-byte form the module takes. */
+function idsToBytes(ids: string[]): Uint8Array {
+    const bytes = new Uint8Array(ids.length * 16);
+    ids.forEach((id, i) => {
+        const hex = id.replaceAll('-', '');
+        for (let j = 0; j < 16; j++) {
+            bytes[i * 16 + j] = parseInt(hex.slice(2 * j, 2 * j + 2), 16);
+        }
+    });
+    return bytes;
+}
+
+/** The engine in the page, as the WebAssembly module of `gpx-rs`. */
+export async function createWasmBackend(): Promise<Backend> {
+    const w: Wasm = await import('gpx-rs');
+    w.start();
+
+    const mode = (m: SelectMode) =>
+        ({ replace: w.SelectMode.Replace, add: w.SelectMode.Add, toggle: w.SelectMode.Toggle })[m];
+    const splitType = (t: SplitType) =>
+        ({ files: w.SplitType.Files, tracks: w.SplitType.Tracks, segments: w.SplitType.Segments })[
+            t
+        ];
+    const mergeType = (t: MergeType) => (t === 'connect' ? w.MergeType.Connect : w.MergeType.Group);
+
+    return {
+        select: lift((ids, m) => w.select(idsToBytes(ids), mode(m))),
+        select_all: lift(w.select_all),
+        arrow_select: lift(w.arrow_select),
+        select_tracks: lift((file, ids, m) => w.select_tracks(file, idsToBytes(ids), mode(m))),
+        select_segments: lift((file, track, ids, m) =>
+            w.select_segments(file, track, idsToBytes(ids), mode(m))
+        ),
+        select_waypoint_group: lift((file, m) => w.select_waypoint_group(file, mode(m))),
+        select_waypoints: lift((file, ids, m) =>
+            w.select_waypoints(file, idsToBytes(ids), mode(m))
+        ),
+
+        undo: lift(w.undo),
+        redo: lift(w.redo),
+        copy: lift(w.copy),
+        cut: lift(w.cut),
+        paste: lift(w.paste),
+
+        new_file: lift(w.new_file),
+        load_files: lift((files) => {
+            const lengths = Uint32Array.from(files.map((file) => file.data.length));
+            const data = new Uint8Array(lengths.reduce((sum, length) => sum + length, 0));
+            let offset = 0;
+            for (const file of files) {
+                data.set(file.data, offset);
+                offset += file.data.length;
+            }
+            return w.load_files(
+                data,
+                lengths,
+                files.map((file) => file.name)
+            );
+        }),
+        duplicate: lift(w.duplicate),
+        delete: lift(w._delete),
+        delete_all: lift(w.delete_all),
+        reorder: lift((ids, index) => w.reorder(idsToBytes(ids), index)),
+        move_elements: lift(w.move_elements),
+        metadata: lift(w.metadata),
+        style: lift(w.style),
+        new_track: lift(w.new_track),
+        new_track_segment: lift(w.new_track_segment),
+
+        new_waypoint: lift(w.new_waypoint),
+        update_waypoint: lift(w.update_waypoint),
+        move_waypoint: lift(w.move_waypoint),
+        delete_waypoint: lift(w.delete_waypoint),
+
+        reverse: lift(w.reverse),
+        extract: lift(w.extract),
+        round_trip: lift(w.round_trip),
+        elevation: lift(w.elevation),
+        change_timestamps: lift(w.changeTimestamps),
+        create_artificial_timestamps: lift(w.createArtificialTimestamps),
+        clean: lift((west, south, east, north, inside, trackpoints, waypoints) =>
+            w.clean(
+                west,
+                south,
+                east,
+                north,
+                inside ? w.CleanType.Inside : w.CleanType.Outside,
+                trackpoints,
+                waypoints
+            )
+        ),
+        merge: lift((type, removeGaps) => w.merge(mergeType(type), removeGaps)),
+        reduce: lift(w.reduce),
+        crop: lift(w.crop),
+        split: lift((revision, at, type) => w.split(revision, at, splitType(type))),
+        route: lift(w.route),
+        insert_anchor: lift(w.insert_anchor),
+        change_loop_start: lift(w.change_loop_start),
+
+        can_undo: lift(w.can_undo),
+        can_redo: lift(w.can_redo),
+        can_paste: lift(w.can_paste),
+        clipboard: lift(w.clipboard),
+        selection: lift(w.selection),
+        file_order: lift(w.file_order),
+        file_structure: lift(w.file_structure),
+        file_statistics: lift(w.file_statistics),
+        waypoint: lift(w.waypoint),
+        trackpoint: lift(w.trackpoint),
+        // a copy out of the memory of the engine, so a plain ArrayBuffer
+        export_file: lift(
+            (...args: Parameters<Backend['export_file']>) =>
+                w.export_file(...args) as Uint8Array<ArrayBuffer> | undefined
+        ),
+        exportable_data: lift((ids) => w.exportable_data(idsToBytes(ids))),
+        reduction_distances: lift(w.reduction_distances),
+        segment_coordinates: lift(w.segment_coordinates),
+        waypoint_coordinates: lift(w.waypoint_coordinates),
+
+        selection_statistics: lift(w.selection_statistics),
+        slice_statistics: lift(w.slice_statistics),
+        total_distance: lift(w.total_distance),
+        slope: lift(w.slope),
+        lng: lift(w.lng),
+        lat: lift(w.lat),
+        ele: lift(w.ele),
+        timestamps: lift(w.timestamps),
+        speed: lift(w.speed),
+        hr: lift(w.hr),
+        cad: lift(w.cad),
+        atemp: lift(w.atemp),
+        power: lift(w.power),
+        slope_segment_slope: lift(w.slope_segment_slope),
+        slope_segment_distance: lift(w.slope_segment_distance),
+        surface_starts: lift(w.surface_starts),
+        surface_values: lift(w.surface_values),
+        surfaces: lift(w.surfaces),
+        highway_starts: lift(w.highway_starts),
+        highway_values: lift(w.highway_values),
+        highways: lift(w.highways),
+        sac_scale_starts: lift(w.sac_scale_starts),
+        sac_scale_values: lift(w.sac_scale_values),
+        sac_scales: lift(w.sac_scales),
+        mtb_scale_starts: lift(w.mtb_scale_starts),
+        mtb_scale_values: lift(w.mtb_scale_values),
+        mtb_scales: lift(w.mtb_scales),
+        anchor_indices: lift(w.anchor_indices),
+        anchor_zooms: lift(w.anchor_zooms),
+        segment_starts: lift(w.segment_starts),
+        segment_ids: lift(w.segment_ids),
+        routing_revision: lift(w.routing_revision),
+
+        importsLegacyData: true,
+        open_storage: (name, onSaved, onBehind, onNewer) =>
+            w.open_storage(name, onSaved, onBehind, onNewer),
+        flush_storage: () => w.flush_storage(),
+        sync_storage: () => w.sync_storage(),
+        set_setting: lift(w.set_setting),
+        delete_setting: lift(w.delete_setting),
+    };
+}

website/src/lib/engine/convert.ts

@@ -1,16 +1,3 @@
-import type { SelectMode } from './types';
-
-export type Wasm = typeof import('gpx-rs');
-
-/** The enumeration of the engine for a way to combine a selection. */
-export function selectMode(wasm: Wasm, mode: SelectMode) {
-    return {
-        replace: wasm.SelectMode.Replace,
-        add: wasm.SelectMode.Add,
-        toggle: wasm.SelectMode.Toggle,
-    }[mode];
-}
-
 /** A flat `[lng, lat, ...]` array as positions. */
 export function toPositions(flat: Float64Array): [number, number][] {
     const positions: [number, number][] = new Array(flat.length / 2);
@@ -19,15 +6,3 @@ export function toPositions(flat: Float64Array): [number, number][] {
     }
     return positions;
 }
-
-export /** Hyphenated UUID strings (as found in the file structures) to the concatenated 16-byte form. */
-function idsToBytes(ids: string[]): Uint8Array {
-    const bytes = new Uint8Array(ids.length * 16);
-    ids.forEach((id, i) => {
-        const hex = id.replaceAll('-', '');
-        for (let j = 0; j < 16; j++) {
-            bytes[i * 16 + j] = parseInt(hex.slice(2 * j, 2 * j + 2), 16);
-        }
-    });
-    return bytes;
-}

website/src/lib/engine/engine.test.ts

@@ -218,7 +218,7 @@ describe('statistics', () => {
         assert.equal(get(engine.statistics).hr, undefined);
 
         const request = engine.requestStatistics();
-        request.set(['hr', 'anchors']);
+        await request.set(['hr', 'anchors']);
         const statistics = get(engine.statistics);
         assert.equal(statistics.hr!.length, statistics.length);
         assert.ok(statistics.hr!.some((hr) => !Number.isNaN(hr)));
@@ -239,14 +239,14 @@ describe('statistics', () => {
     it('gives the statistics of a part of the selection', async () => {
         await load('simple');
         const statistics = get(engine.statistics);
-        const part = statistics.slice(2, 5)!;
+        const part = (await statistics.slice(2, 5))!;
         assert.ok(part.totalDistance > 0);
         assert.ok(part.totalDistance < statistics.global.totalDistance);
-        assert.equal(statistics.slice(0, statistics.length + 10), undefined);
+        assert.equal(await statistics.slice(0, statistics.length + 10), undefined);
 
         // a slice is only valid for the selection it was made on
         await engine.select([]);
-        assert.equal(statistics.slice(2, 5), undefined);
+        assert.equal(await statistics.slice(2, 5), undefined);
     });
 });
 
@@ -304,7 +304,7 @@ describe('file state', () => {
         const file = fileStates()[0];
         assert.ok(file.waypoints.features.length > 0);
         const feature = file.waypoints.features[0];
-        const details = engine.waypoint(file.structure.id, feature.properties.waypointId)!;
+        const details = (await engine.waypoint(file.structure.id, feature.properties.waypointId))!;
         assert.deepEqual(feature.geometry.coordinates, [details.lng, details.lat]);
         assert.equal(feature.properties.name, details.name);
         assert.equal(details.links?.[0].href, 'https://gpx.studio');
@@ -330,23 +330,23 @@ describe('waypoints', () => {
         const id = file.waypoints.features[0].properties.waypointId;
         const fileId = file.structure.id;
 
-        let details = engine.waypoint(fileId, id)!;
+        let details = (await engine.waypoint(fileId, id))!;
         assert.equal(details.name, 'summit');
         assert.equal(details.sym, 'Summit');
         assert.equal(details.links![0].href, 'https://example.com');
 
         await engine.updateWaypoint(fileId, id, { ...waypoint, name: 'peak', link: '' });
-        details = engine.waypoint(fileId, id)!;
+        details = (await engine.waypoint(fileId, id))!;
         assert.equal(details.name, 'peak');
         assert.equal(details.links, undefined);
 
         await engine.moveWaypoint(fileId, id, 5, 51, 200);
         assert.deepEqual(fileStates()[0].waypoints.features[0].geometry.coordinates, [5, 51]);
-        assert.equal(engine.waypoint(fileId, id)!.ele, 200);
+        assert.equal((await engine.waypoint(fileId, id))!.ele, 200);
 
         await engine.deleteWaypoint(fileId, id);
         assert.equal(fileStates()[0].waypoints.features.length, 0);
-        assert.equal(engine.waypoint(fileId, id), undefined);
+        assert.equal(await engine.waypoint(fileId, id), undefined);
         assert.equal(await engine.deleteWaypoint(fileId, id), false);
     });
 });
@@ -395,8 +395,10 @@ describe('observer of the files', () => {
 });
 
 describe('export', () => {
-    const text = (id: string, options: Partial<ExportOptions> = {}) =>
-        new TextDecoder().decode(engine.exportFile(id, { ...ALL_EXPORT_OPTIONS, ...options }));
+    const text = async (id: string, options: Partial<ExportOptions> = {}) =>
+        new TextDecoder().decode(
+            await engine.exportFile(id, { ...ALL_EXPORT_OPTIONS, ...options })
+        );
 
     it('writes tracks, or routes when asked to', async () => {
         await load('with_tracks_and_segments');
@@ -407,11 +409,11 @@ describe('export', () => {
         );
         const id = file.structure.id;
 
-        const tracks = text(id);
+        const tracks = await text(id);
         assert.ok(tracks.includes('<trk>') && !tracks.includes('<rte>'));
         assert.equal(tracks.match(/<trkseg>/g)?.length, segments);
 
-        const routes = text(id, { asRoute: true });
+        const routes = await text(id, { asRoute: true });
         assert.ok(routes.includes('<rte>') && !routes.includes('<trk>'));
         assert.equal(routes.match(/<rte>/g)?.length, segments);
         assert.ok(routes.includes('<rtept'));
@@ -419,7 +421,7 @@ describe('export', () => {
 
     it('does not count the way a file is written among its data', async () => {
         await load('simple');
-        const data = engine.exportableData(get(engine.order));
+        const data = await engine.exportableData(get(engine.order));
         assert.equal(data.asRoute, false);
     });
 
@@ -427,7 +429,7 @@ describe('export', () => {
         await load('with_tracks_and_segments');
         const id = get(engine.order)[0];
         const before = fileStates()[0].segments.features.length;
-        const routes = engine.exportFile(id, { ...ALL_EXPORT_OPTIONS, asRoute: true })!;
+        const routes = (await engine.exportFile(id, { ...ALL_EXPORT_OPTIONS, asRoute: true }))!;
         await engine.loadFiles([{ data: routes, name: 'routes' }]);
         const [, loaded] = get(engine.order);
         const state = get(get(engine.files).get(loaded)!);

website/src/lib/engine/engine.ts

@@ -10,7 +10,7 @@ import {
 import { categoryIntervals } from '$lib/engine/trackpoint-categories';
 import { selectedElementIds, type FileTreeNode } from '$lib/engine/selection-helpers';
 import type { RouteAttributes } from 'gpx-rs';
-import { idsToBytes, selectMode, type Wasm } from './convert';
+import { loadBackend, type Backend } from './backend';
 import { readFileState } from './file-state';
 import { StatisticsReader } from './statistics';
 import { openStoredFiles } from './storage';
@@ -34,7 +34,8 @@ import {
 } from './types';
 
 /**
- * Thin wrapper around the WASM engine.
+ * Thin wrapper around the engine of the files (the WASM module in the browser, the Rust process
+ * in the desktop app: see `backend`).
  *
  * The engine owns the files; this class mirrors what the UI needs in stores. After each action,
  * only what the engine reports as changed is read again: the order of the files, and the state
@@ -42,7 +43,9 @@ import {
  * segments and waypoints that did not change are reused.
  */
 class Engine {
-    private wasm: Wasm | null = null;
+    private backend: Backend | null = null;
+    /** The calls to the engine, one after the other: each one is applied before the next starts. */
+    private _queue: Promise<unknown> = Promise.resolve();
     /** Resolves once the engine can be used (never on the server). */
     readonly ready: Promise<void>;
 
@@ -61,7 +64,7 @@ class Engine {
     private _canRedo = writable(false);
     private _canPaste = writable(false);
     private _clipboard = writable<Clipboard | undefined>(undefined);
-    private _statistics = new StatisticsReader(() => this.wasm);
+    private _statistics = new StatisticsReader((task) => this.enqueue(task));
 
     /** Ids of the files in display order. */
     readonly order: Readable<string[]> = { subscribe: this._order.subscribe };
@@ -89,9 +92,8 @@ class Engine {
 
     constructor() {
         this.ready = browser
-            ? import('gpx-rs').then((wasm) => {
-                  wasm.start();
-                  this.wasm = wasm;
+            ? loadBackend().then((backend) => {
+                  this.backend = backend;
               })
             : new Promise(() => {});
     }
@@ -110,9 +112,9 @@ class Engine {
     openStorage(): Promise<Record<string, string>> {
         this._storage ??= this.ready.then(() =>
             openStoredFiles({
-                wasm: this.wasm!,
+                backend: this.backend!,
                 visibility: this._visibility,
-                sync: (update) => this.sync(this.wasm!, update),
+                sync: (update) => this.enqueue(() => this.sync(this.backend!, update)),
                 outdated: () => this._outdated.set(true),
                 hasFiles: () => get(this._order).length > 0,
                 loadFiles: (files) => this.loadFiles(files),
@@ -124,11 +126,11 @@ class Engine {
 
     /** Keeps a setting, `json` being its JSON. Nothing is kept before `openStorage` is done. */
     setSetting(key: string, json: string) {
-        this.wasm?.set_setting(key, json);
+        void this.backend?.set_setting(key, json);
     }
 
     deleteSetting(key: string) {
-        this.wasm?.delete_setting(key);
+        void this.backend?.delete_setting(key);
     }
 
     // Selection. Like the edits, each action resolves to whether the engine changed something.
@@ -138,7 +140,7 @@ class Engine {
      * `SelectMode` for how the files combine with the selection.
      */
     select(fileIds: string[], mode: SelectMode = 'replace') {
-        return this.run((w) => w.select(idsToBytes(fileIds), selectMode(w, mode)));
+        return this.run((b) => b.select(fileIds, mode));
     }
 
     /**
@@ -147,7 +149,7 @@ class Engine {
      * the files when nothing is selected.
      */
     selectAll() {
-        return this.run((w) => w.select_all());
+        return this.run((b) => b.select_all());
     }
 
     /**
@@ -156,13 +158,13 @@ class Engine {
      * it replaces it.
      */
     arrowSelect(down: boolean, add: boolean) {
-        return this.run((w) => w.arrow_select(down, add));
+        return this.run((b) => b.arrow_select(down, add));
     }
 
     // Selecting elements inside a file. Ids that do not exist are ignored.
 
     selectTracks(fileId: string, trackIds: string[], mode: SelectMode = 'replace') {
-        return this.run((w) => w.select_tracks(fileId, idsToBytes(trackIds), selectMode(w, mode)));
+        return this.run((b) => b.select_tracks(fileId, trackIds, mode));
     }
 
     selectSegments(
@@ -171,20 +173,16 @@ class Engine {
         segmentIds: string[],
         mode: SelectMode = 'replace'
     ) {
-        return this.run((w) =>
-            w.select_segments(fileId, trackId, idsToBytes(segmentIds), selectMode(w, mode))
-        );
+        return this.run((b) => b.select_segments(fileId, trackId, segmentIds, mode));
     }
 
     /** Selects the node standing for all the waypoints of the file. */
     selectWaypointGroup(fileId: string, mode: SelectMode = 'replace') {
-        return this.run((w) => w.select_waypoint_group(fileId, selectMode(w, mode)));
+        return this.run((b) => b.select_waypoint_group(fileId, mode));
     }
 
     selectWaypoints(fileId: string, waypointIds: string[], mode: SelectMode = 'replace') {
-        return this.run((w) =>
-            w.select_waypoints(fileId, idsToBytes(waypointIds), selectMode(w, mode))
-        );
+        return this.run((b) => b.select_waypoints(fileId, waypointIds, mode));
     }
 
     /** Selects a node of the file tree. */
@@ -206,23 +204,23 @@ class Engine {
     // History
 
     undo() {
-        return this.run((w) => w.undo());
+        return this.run((b) => b.undo());
     }
 
     redo() {
-        return this.run((w) => w.redo());
+        return this.run((b) => b.redo());
     }
 
     // Clipboard
 
     /** Puts the selected elements in the clipboard. */
     copy() {
-        return this.run((w) => w.copy());
+        return this.run((b) => b.copy());
     }
 
     /** Like `copy`, but the elements are moved when they are pasted. */
     cut() {
-        return this.run((w) => w.cut());
+        return this.run((b) => b.cut());
     }
 
     // Edits of the files
@@ -232,7 +230,7 @@ class Engine {
      * segment that hold it, in the same undo step.
      */
     newFile(name: string, trackpoint?: { lng: number; lat: number; ele?: number }) {
-        return this.run((w) => w.new_file(name, trackpoint?.lng, trackpoint?.lat, trackpoint?.ele));
+        return this.run((b) => b.new_file(name, trackpoint?.lng, trackpoint?.lat, trackpoint?.ele));
     }
 
     /**
@@ -241,24 +239,11 @@ class Engine {
      * the first one that was read is selected.
      */
     loadFiles(files: { data: Uint8Array; name: string }[]) {
-        const lengths = Uint32Array.from(files.map((file) => file.data.length));
-        const data = new Uint8Array(lengths.reduce((sum, length) => sum + length, 0));
-        let offset = 0;
-        for (const file of files) {
-            data.set(file.data, offset);
-            offset += file.data.length;
-        }
-        return this.run((w) =>
-            w.load_files(
-                data,
-                lengths,
-                files.map((file) => file.name)
-            )
-        );
+        return this.run((b) => b.load_files(files));
     }
 
     duplicate() {
-        return this.run((w) => w.duplicate());
+        return this.run((b) => b.duplicate());
     }
 
     /**
@@ -266,16 +251,16 @@ class Engine {
      * are deleted instead, even if only a track or a waypoint is selected.
      */
     delete(wholeFiles = false) {
-        return this.run((w) => w._delete(wholeFiles));
+        return this.run((b) => b.delete(wholeFiles));
     }
 
     deleteAll() {
-        return this.run((w) => w.delete_all());
+        return this.run((b) => b.delete_all());
     }
 
     /** Moves the files, in the given order, to `index` among the other files. */
     reorder(fileIds: string[], index: number) {
-        return this.run((w) => w.reorder(idsToBytes(fileIds), index));
+        return this.run((b) => b.reorder(fileIds, index));
     }
 
     /**
@@ -289,7 +274,7 @@ class Engine {
      * copied again, what was cut is moved the first time and copied after that.
      */
     paste() {
-        return this.run((w) => w.paste());
+        return this.run((b) => b.paste());
     }
 
     /**
@@ -303,7 +288,7 @@ class Engine {
      * node), among the waypoints of a file.
      */
     move(what: Selection, to: MoveTarget) {
-        return this.run((w) => w.move_elements(what, to));
+        return this.run((b) => b.move_elements(what, to));
     }
 
     // Edits of the waypoints
@@ -313,8 +298,8 @@ class Engine {
      * strings are fields that the waypoint does not have.
      */
     newWaypoint(waypoint: NewWaypoint) {
-        return this.run((w) =>
-            w.new_waypoint(
+        return this.run((b) =>
+            b.new_waypoint(
                 waypoint.lng,
                 waypoint.lat,
                 waypoint.ele,
@@ -328,8 +313,8 @@ class Engine {
 
     /** Changes a waypoint, selected or not. Empty strings remove the field. */
     updateWaypoint(fileId: string, waypointId: string, waypoint: NewWaypoint) {
-        return this.run((w) =>
-            w.update_waypoint(
+        return this.run((b) =>
+            b.update_waypoint(
                 fileId,
                 waypointId,
                 waypoint.lng,
@@ -345,22 +330,22 @@ class Engine {
 
     /** Moves a waypoint, selected or not: only its position and elevation change. */
     moveWaypoint(fileId: string, waypointId: string, lng: number, lat: number, ele: number) {
-        return this.run((w) => w.move_waypoint(fileId, waypointId, lng, lat, ele));
+        return this.run((b) => b.move_waypoint(fileId, waypointId, lng, lat, ele));
     }
 
     /** Deletes a waypoint, selected or not. */
     deleteWaypoint(fileId: string, waypointId: string) {
-        return this.run((w) => w.delete_waypoint(fileId, waypointId));
+        return this.run((b) => b.delete_waypoint(fileId, waypointId));
     }
 
     // Edits of the selection
 
     newTrack() {
-        return this.run((w) => w.new_track());
+        return this.run((b) => b.new_track());
     }
 
     newTrackSegment() {
-        return this.run((w) => w.new_track_segment());
+        return this.run((b) => b.new_track_segment());
     }
 
     /**
@@ -369,7 +354,7 @@ class Engine {
      * nothing to reverse (fewer than two trackpoints).
      */
     reverse() {
-        return this.run((w) => w.reverse());
+        return this.run((b) => b.reverse());
     }
 
     /**
@@ -378,7 +363,7 @@ class Engine {
      * Resolves to `false` when there is nothing to extract.
      */
     extract() {
-        return this.run((w) => w.extract());
+        return this.run((b) => b.extract());
     }
 
     /**
@@ -387,7 +372,7 @@ class Engine {
      * number of elevations is not the number of trackpoints.
      */
     setElevation(ele: Float64Array) {
-        return this.run((w) => w.elevation(ele));
+        return this.run((b) => b.elevation(ele));
     }
 
     /**
@@ -396,7 +381,7 @@ class Engine {
      * `speed` (km/h). Resolves to `false` when there is nothing to set, or the values are invalid.
      */
     changeTimestamps(startTime: Date, speed: number, ratio: number) {
-        return this.run((w) => w.changeTimestamps(startTime.getTime(), speed, ratio));
+        return this.run((b) => b.change_timestamps(startTime.getTime(), speed, ratio));
     }
 
     /**
@@ -405,7 +390,7 @@ class Engine {
      * nothing to set.
      */
     createArtificialTimestamps(startTime: Date, totalTime: number) {
-        return this.run((w) => w.createArtificialTimestamps(startTime.getTime(), totalTime));
+        return this.run((b) => b.create_artificial_timestamps(startTime.getTime(), totalTime));
     }
 
     /**
@@ -418,13 +403,13 @@ class Engine {
         trackpoints: boolean,
         waypoints: boolean
     ) {
-        return this.run((w) =>
-            w.clean(
+        return this.run((b) =>
+            b.clean(
                 bounds.west,
                 bounds.south,
                 bounds.east,
                 bounds.north,
-                inside ? w.CleanType.Inside : w.CleanType.Outside,
+                inside,
                 trackpoints,
                 waypoints
             )
@@ -437,9 +422,7 @@ class Engine {
      * Resolves to `false` when there is nothing to merge.
      */
     merge(type: MergeType, removeGaps = false) {
-        return this.run((w) =>
-            w.merge(type === 'connect' ? w.MergeType.Connect : w.MergeType.Group, removeGaps)
-        );
+        return this.run((b) => b.merge(type, removeGaps));
     }
 
     /**
@@ -448,7 +431,7 @@ class Engine {
      * is nothing to remove.
      */
     reduce(tolerance: number) {
-        return this.run((w) => w.reduce(tolerance));
+        return this.run((b) => b.reduce(tolerance));
     }
 
     /**
@@ -458,17 +441,7 @@ class Engine {
      * one of `SelectionAnchors`, which `at` is an index of.
      */
     split(revision: number, at: number, splitType: SplitType) {
-        return this.run((w) =>
-            w.split(
-                revision,
-                at,
-                {
-                    files: w.SplitType.Files,
-                    tracks: w.SplitType.Tracks,
-                    segments: w.SplitType.Segments,
-                }[splitType]
-            )
-        );
+        return this.run((b) => b.split(revision, at, splitType));
     }
 
     /**
@@ -478,7 +451,7 @@ class Engine {
      * the range covers the whole selection.
      */
     crop(start: number, end: number) {
-        return this.run((w) => w.crop(Math.max(start, 0), Math.max(end, 0)));
+        return this.run((b) => b.crop(Math.max(start, 0), Math.max(end, 0)));
     }
 
     /**
@@ -487,16 +460,16 @@ class Engine {
      * repeated), and goes on in time. Resolves to `false` when no segment has the two trackpoints that a way back needs.
      */
     roundTrip() {
-        return this.run((w) => w.round_trip());
+        return this.run((b) => b.round_trip());
     }
 
     metadata(name: string, desc: string) {
-        return this.run((w) => w.metadata(name, desc));
+        return this.run((b) => b.metadata(name, desc));
     }
 
     /** Only the given fields are changed. */
     style(style: { color?: string; opacity?: number; width?: number }) {
-        return this.run((w) => w.style(style.color, style.opacity, style.width));
+        return this.run((b) => b.style(style.color, style.opacity, style.width));
     }
 
     // Routing
@@ -529,8 +502,8 @@ class Engine {
                 routeAttributes[key] = intervals;
             }
         }
-        return this.run((w) =>
-            w.route(
+        return this.run((b) =>
+            b.route(
                 revision,
                 start,
                 end,
@@ -549,7 +522,7 @@ class Engine {
      * one of `SelectionAnchors`.
      */
     insertAnchor(revision: number, lng: number, lat: number) {
-        return this.run((w) => w.insert_anchor(revision, lng, lat));
+        return this.run((b) => b.insert_anchor(revision, lng, lat));
     }
 
     /**
@@ -557,7 +530,7 @@ class Engine {
      * the trackpoints before it go to the end, and the loop closes on it. `revision` is the one of `SelectionAnchors`.
      */
     changeLoopStart(revision: number, index: number) {
-        return this.run((w) => w.change_loop_start(revision, index));
+        return this.run((b) => b.change_loop_start(revision, index));
     }
 
     // Visibility, which is kept by the frontend and not by the engine
@@ -601,16 +574,20 @@ class Engine {
         }
     }
 
-    // Requests, which do not change anything
+    // Requests, which do not change anything. They wait for the calls made before them.
 
     /** All the data of a waypoint, `undefined` if it does not exist (or before the engine is loaded). */
-    waypoint(fileId: string, waypointId: string): WaypointDetails | undefined {
-        return this.wasm?.waypoint(fileId, waypointId);
+    waypoint(fileId: string, waypointId: string): Promise<WaypointDetails | undefined> {
+        return this.read((b) => b.waypoint(fileId, waypointId), undefined);
     }
 
     /** A trackpoint of a segment, `undefined` if it does not exist. */
-    trackpoint(fileId: string, segmentId: string, index: number): TrackpointDetails | undefined {
-        return this.wasm?.trackpoint(fileId, segmentId, index);
+    trackpoint(
+        fileId: string,
+        segmentId: string,
+        index: number
+    ): Promise<TrackpointDetails | undefined> {
+        return this.read((b) => b.trackpoint(fileId, segmentId, index), undefined);
     }
 
     /**
@@ -620,9 +597,10 @@ class Engine {
     exportFile(
         fileId: string,
         options: ExportOptions = ALL_EXPORT_OPTIONS
-    ): Uint8Array<ArrayBuffer> | undefined {
-        // a copy out of the memory of the engine, so a plain ArrayBuffer
-        return this.wasm?.export_file(
+    ): Promise<Uint8Array<ArrayBuffer> | undefined> {
+        return this.read(
+            (b) =>
+                b.export_file(
                     fileId,
                     options.time,
                     options.hr,
@@ -631,12 +609,14 @@ class Engine {
                     options.power,
                     options.osm,
                     options.asRoute
-        ) as Uint8Array<ArrayBuffer> | undefined;
+                ),
+            undefined
+        );
     }
 
     /** The data that some files have, which the options of `exportFile` can leave out. */
-    exportableData(fileIds: string[]): ExportOptions {
-        const bits = this.wasm?.exportable_data(idsToBytes(fileIds)) ?? 0;
+    async exportableData(fileIds: string[]): Promise<ExportOptions> {
+        const bits = await this.read((b) => b.exportable_data(fileIds), 0);
         return {
             time: (bits & 1) !== 0,
             hr: (bits & 2) !== 0,
@@ -654,19 +634,19 @@ class Engine {
      * (m) of `reduce` that keeps it: infinite for the ends of the segments. Not requested with
      * the statistics: ask when they changed.
      */
-    reductionDistances(): Float64Array {
-        return this.wasm?.reduction_distances() ?? new Float64Array();
+    reductionDistances(): Promise<Float64Array> {
+        return this.read((b) => b.reduction_distances(), new Float64Array());
     }
 
-    // Coordinates, as flat [lng, lat, ...] arrays. The getters copy them out of the WASM memory.
+    // Coordinates, as flat [lng, lat, ...] arrays: copies.
     // Refetch them when the `rev` of the segment (or the `waypointsRev` of the file) changed.
 
-    segmentCoordinates(segmentId: string): Float64Array {
-        return this.wasm?.segment_coordinates(segmentId) ?? new Float64Array();
+    segmentCoordinates(segmentId: string): Promise<Float64Array> {
+        return this.read((b) => b.segment_coordinates(segmentId), new Float64Array());
     }
 
-    waypointCoordinates(fileId: string): Float64Array {
-        return this.wasm?.waypoint_coordinates(fileId) ?? new Float64Array();
+    waypointCoordinates(fileId: string): Promise<Float64Array> {
+        return this.read((b) => b.waypoint_coordinates(fileId), new Float64Array());
     }
 
     /**
@@ -682,17 +662,34 @@ class Engine {
 
     // Plumbing
 
+    /** Does `task` after the ones that were queued before it, whatever they do. */
+    private enqueue<T>(task: () => Promise<T>): Promise<T> {
+        const result = this._queue.then(task, task);
+        this._queue = result.catch(() => {});
+        return result;
+    }
+
+    /**
+     * Makes a request to the engine, once the calls made before it are done. Resolves to
+     * `fallback` when the engine is not loaded.
+     */
+    private read<T>(request: (backend: Backend) => Promise<T>, fallback: T): Promise<T> {
+        return this.enqueue(async () => (this.backend ? request(this.backend) : fallback));
+    }
+
     /**
      * Makes a call to the engine and applies its outcome to what is kept of the files. Resolves to
      * whether anything changed. When nothing did, `lastError` tells why.
      */
-    private async run(action: (wasm: Wasm) => Outcome): Promise<boolean> {
+    private async run(action: (backend: Backend) => Promise<Outcome>): Promise<boolean> {
         await this.ready;
-        const wasm = this.wasm!;
-        const outcome = action(wasm);
-        this.sync(wasm, outcome);
+        return this.enqueue(async () => {
+            const backend = this.backend!;
+            const outcome = await action(backend);
+            await this.sync(backend, outcome);
             this.report(outcome);
             return outcome.changed;
+        });
     }
 
     /** Logs why a call did nothing, and keeps it in `lastError`. */
@@ -706,26 +703,34 @@ class Engine {
     }
 
     /** Updates what is kept of the engine with what a call changed. */
-    private sync(wasm: Wasm, update: Outcome) {
-        this._canUndo.set(wasm.can_undo());
-        this._canRedo.set(wasm.can_redo());
-        this._canPaste.set(wasm.can_paste());
+    private async sync(backend: Backend, update: Outcome) {
+        const [canUndo, canRedo, canPaste] = await Promise.all([
+            backend.can_undo(),
+            backend.can_redo(),
+            backend.can_paste(),
+        ]);
+        this._canUndo.set(canUndo);
+        this._canRedo.set(canRedo);
+        this._canPaste.set(canPaste);
         if (update.clipboardChanged) {
-            this._clipboard.set(wasm.clipboard());
+            this._clipboard.set(await backend.clipboard());
         }
         if (update.selectionChanged) {
-            this._selection.set(wasm.selection());
+            this._selection.set(await backend.selection());
         }
         if (update.orderChanged) {
-            this._order.set(wasm.file_order());
+            this._order.set(await backend.file_order());
         }
         const added: [string, FileState][] = [];
-        for (const id of update.added) {
-            const state = readFileState(wasm, id, this._colors, this._visibility);
+        const addedStates = await Promise.all(
+            update.added.map((id) => readFileState(backend, id, this._colors, this._visibility))
+        );
+        update.added.forEach((id, i) => {
+            const state = addedStates[i];
             if (state) {
                 added.push([id, state]);
             }
-        }
+        });
         if (added.length > 0 || update.removed.length > 0) {
             this._files.update((files) => {
                 const next = new Map(files);
@@ -739,14 +744,22 @@ class Engine {
         }
         if (update.modified.length > 0) {
             const files = get(this._files);
-            for (const id of update.modified) {
+            const states = await Promise.all(
+                update.modified.map((id) => {
                     const store = files.get(id);
-                const state =
-                    store && readFileState(wasm, id, this._colors, this._visibility, get(store));
+                    return (
+                        store &&
+                        readFileState(backend, id, this._colors, this._visibility, get(store))
+                    );
+                })
+            );
+            update.modified.forEach((id, i) => {
+                const store = files.get(id);
+                const state = states[i];
                 if (store && state) {
                     store.set(state);
                 }
-            }
+            });
         }
 
         // the statistics depend on the selection, on its order, and on the files
@@ -755,7 +768,7 @@ class Engine {
             update.orderChanged ||
             update.added.length + update.modified.length + update.removed.length > 0
         ) {
-            this._statistics.refresh(wasm);
+            await this._statistics.refresh(backend);
         }
     }
 }

website/src/lib/engine/file-state.ts

@@ -1,18 +1,19 @@
 import type { Feature, LineString } from 'geojson';
 import { normalizeColor, type FileColorAllocator } from '$lib/engine/file-colors';
 import type { Visibility } from '$lib/engine/file-visibility';
-import { toPositions, type Wasm } from './convert';
+import type { Backend } from './backend';
+import { toPositions } from './convert';
 import { EMPTY_STATISTICS, type FileState, type SegmentProperties } from './types';
 
 /** Reads the state of a file, reusing from `previous` what did not change. */
-export function readFileState(
-    wasm: Wasm,
+export async function readFileState(
+    backend: Backend,
     id: string,
     colors: FileColorAllocator,
     visibility: ReadonlyMap<string, Visibility>,
     previous?: FileState
-): FileState | null {
-    const structure = wasm.file_structure(id);
+): Promise<FileState | null> {
+    const structure = await backend.file_structure(id);
     if (!structure) {
         return null;
     }
@@ -25,7 +26,11 @@ export function readFileState(
     const previousSegments = new Map(
         previous?.segments.features.map((f) => [f.properties.segmentId, f]) ?? []
     );
-    const segments: Feature<LineString, SegmentProperties>[] = [];
+    // the coordinates of the segments that changed, read together
+    const segments: (
+        | Feature<LineString, SegmentProperties>
+        | Promise<Feature<LineString, SegmentProperties>>
+    )[] = [];
     structure.tracks.forEach((track, trackIndex) => {
         track.segments.forEach((segment, segmentIndex) => {
             const properties: SegmentProperties = {
@@ -48,17 +53,18 @@ export function readFileState(
             segments.push(
                 unchanged
                     ? old
-                    : {
+                    : backend.segment_coordinates(segment.id).then((coordinates) => ({
                           type: 'Feature',
                           geometry: {
                               type: 'LineString',
-                              coordinates: toPositions(wasm.segment_coordinates(segment.id)),
+                              coordinates: toPositions(coordinates),
                           },
                           properties,
-                      }
+                      }))
             );
         });
     });
+    const segmentFeatures = await Promise.all(segments);
 
     const previousStructure = previous?.structure;
     const waypointsUnchanged =
@@ -73,7 +79,7 @@ export function readFileState(
         );
     let waypoints = previous?.waypoints;
     if (!waypoints || !waypointsUnchanged) {
-        const coordinates = toPositions(wasm.waypoint_coordinates(id));
+        const coordinates = toPositions(await backend.waypoint_coordinates(id));
         waypoints = {
             type: 'FeatureCollection',
             features: structure.waypoints.map((waypoint, index) => ({
@@ -93,8 +99,8 @@ export function readFileState(
     return {
         structure,
         color,
-        statistics: wasm.file_statistics(id) ?? EMPTY_STATISTICS,
-        segments: { type: 'FeatureCollection', features: segments },
+        statistics: (await backend.file_statistics(id)) ?? EMPTY_STATISTICS,
+        segments: { type: 'FeatureCollection', features: segmentFeatures },
         waypoints,
         visibility: visibility.get(id) ?? new Map(),
     };

website/src/lib/engine/statistics.ts

@@ -1,6 +1,6 @@
 import { get, writable, type Readable } from 'svelte/store';
 import { categoryIntervals, type CategoryIntervals } from '$lib/engine/trackpoint-categories';
-import type { Wasm } from './convert';
+import type { Backend } from './backend';
 import {
     EMPTY_SELECTION_STATISTICS,
     EMPTY_STATISTICS,
@@ -23,35 +23,49 @@ export class StatisticsReader {
     /** The metrics that were read for the current statistics. */
     private _loaded = new Set<StatisticsMetric>();
 
-    /** @param wasm The engine, `null` before it is loaded. */
-    constructor(private wasm: () => Wasm | null) {}
+    /** The engine, as of the last time the statistics were read. */
+    private _backend: Backend | null = null;
+
+    /** @param enqueue Does a task after the calls to the engine that were made before it. */
+    constructor(private enqueue: <T>(task: () => Promise<T>) => Promise<T>) {}
 
     /** Reads the statistics of the selection again, after it or the files changed. */
-    refresh(wasm: Wasm) {
-        this._store.set(this.read(wasm));
+    async refresh(backend: Backend) {
+        this._backend = backend;
+        this._store.set(await this.read(backend));
     }
 
     /**
      * Reads the statistics buffers of the engine (the getters copy them), but only the metrics
      * that were requested.
      */
-    private read(wasm: Wasm): SelectionStatistics {
+    private async read(backend: Backend): Promise<SelectionStatistics> {
         const version = ++this._version;
         this._loaded.clear();
-        const totalDistance = wasm.total_distance();
+        const [global, totalDistance, slope, lng, lat, ele, timestamps] = await Promise.all([
+            backend.selection_statistics(),
+            backend.total_distance(),
+            backend.slope(),
+            backend.lng(),
+            backend.lat(),
+            backend.ele(),
+            backend.timestamps(),
+        ]);
         const statistics: SelectionStatistics = {
-            global: wasm.selection_statistics() ?? EMPTY_STATISTICS,
+            global: global ?? EMPTY_STATISTICS,
             length: totalDistance.length,
             totalDistance,
-            slope: wasm.slope(),
-            lng: wasm.lng(),
-            lat: wasm.lat(),
-            ele: wasm.ele(),
-            timestamps: wasm.timestamps(),
+            slope,
+            lng,
+            lat,
+            ele,
+            timestamps,
             slice: (start, end) =>
-                version === this._version ? wasm.slice_statistics(start, end) : undefined,
+                this.enqueue(async () =>
+                    version === this._version ? backend.slice_statistics(start, end) : undefined
+                ),
         };
-        this.readMetrics(wasm, statistics, this.requestedMetrics());
+        await this.readMetrics(backend, statistics, this.requestedMetrics());
         return statistics;
     }
 
@@ -62,81 +76,95 @@ export class StatisticsReader {
     }
 
     /** Reads the metrics that were not read yet into `statistics`, which is the current one. */
-    private readMetrics(
-        wasm: Wasm,
+    private async readMetrics(
+        backend: Backend,
         statistics: SelectionStatistics,
         metrics: Set<StatisticsMetric>
     ) {
-        const categories = (
-            starts: Uint32Array,
-            values: Uint8Array,
-            names: () => string[]
-        ): CategoryIntervals => ({
-            starts,
-            values,
-            names: names(),
-        });
+        const categories = async (
+            starts: Promise<Uint32Array>,
+            values: Promise<Uint8Array>,
+            names: Promise<string[]>
+        ): Promise<CategoryIntervals> => {
+            const [s, v, n] = await Promise.all([starts, values, names]);
+            return { starts: s, values: v, names: n };
+        };
 
-        for (const metric of metrics) {
-            if (this._loaded.has(metric)) {
-                continue;
-            }
-            this._loaded.add(metric);
+        const missing = [...metrics].filter((metric) => !this._loaded.has(metric));
+        missing.forEach((metric) => this._loaded.add(metric));
+        await Promise.all(
+            missing.map(async (metric) => {
                 switch (metric) {
                     case 'speed':
-                    statistics.speed = wasm.speed();
+                        statistics.speed = await backend.speed();
                         break;
                     case 'hr':
-                    statistics.hr = wasm.hr();
+                        statistics.hr = await backend.hr();
                         break;
                     case 'cad':
-                    statistics.cad = wasm.cad();
+                        statistics.cad = await backend.cad();
                         break;
                     case 'atemp':
-                    statistics.atemp = wasm.atemp();
+                        statistics.atemp = await backend.atemp();
                         break;
                     case 'power':
-                    statistics.power = wasm.power();
+                        statistics.power = await backend.power();
                         break;
                     case 'slopeSegment':
-                    statistics.slopeSegmentSlope = wasm.slope_segment_slope();
-                    statistics.slopeSegmentDistance = wasm.slope_segment_distance();
+                        [statistics.slopeSegmentSlope, statistics.slopeSegmentDistance] =
+                            await Promise.all([
+                                backend.slope_segment_slope(),
+                                backend.slope_segment_distance(),
+                            ]);
                         break;
                     case 'surface':
-                    statistics.surface = categories(
-                        wasm.surface_starts(),
-                        wasm.surface_values(),
-                        wasm.surfaces
+                        statistics.surface = await categories(
+                            backend.surface_starts(),
+                            backend.surface_values(),
+                            backend.surfaces()
                         );
                         break;
-                case 'anchors':
+                    case 'anchors': {
+                        const [indices, zooms, segmentStarts, segmentIds, revision] =
+                            await Promise.all([
+                                backend.anchor_indices(),
+                                backend.anchor_zooms(),
+                                backend.segment_starts(),
+                                backend.segment_ids(),
+                                backend.routing_revision(),
+                            ]);
                         statistics.anchors = {
-                        indices: wasm.anchor_indices(),
-                        zooms: wasm.anchor_zooms(),
-                        segmentStarts: wasm.segment_starts(),
-                        segmentIds: wasm.segment_ids(),
-                        revision: wasm.routing_revision(),
+                            indices,
+                            zooms,
+                            segmentStarts,
+                            segmentIds,
+                            revision,
                         };
                         break;
+                    }
                     case 'highway':
-                    statistics.highway = categories(
-                        wasm.highway_starts(),
-                        wasm.highway_values(),
-                        wasm.highways
-                    );
-                    statistics.sacScale = categories(
-                        wasm.sac_scale_starts(),
-                        wasm.sac_scale_values(),
-                        wasm.sac_scales
-                    );
-                    statistics.mtbScale = categories(
-                        wasm.mtb_scale_starts(),
-                        wasm.mtb_scale_values(),
-                        wasm.mtb_scales
-                    );
+                        [statistics.highway, statistics.sacScale, statistics.mtbScale] =
+                            await Promise.all([
+                                categories(
+                                    backend.highway_starts(),
+                                    backend.highway_values(),
+                                    backend.highways()
+                                ),
+                                categories(
+                                    backend.sac_scale_starts(),
+                                    backend.sac_scale_values(),
+                                    backend.sac_scales()
+                                ),
+                                categories(
+                                    backend.mtb_scale_starts(),
+                                    backend.mtb_scale_values(),
+                                    backend.mtb_scales()
+                                ),
+                            ]);
                         break;
                 }
-        }
+            })
+        );
     }
 
     /**
@@ -155,7 +183,7 @@ export class StatisticsReader {
                 for (const metric of metrics) {
                     wanted.add(metric);
                 }
-                this.loadMissing();
+                return this.loadMissing();
             },
             release: () => {
                 this._requests.delete(wanted);
@@ -164,16 +192,22 @@ export class StatisticsReader {
     }
 
     /** Reads the requested metrics that are not in the current statistics yet. */
-    private loadMissing() {
-        const wasm = this.wasm();
+    private async loadMissing() {
         const metrics = this.requestedMetrics();
-        if (!wasm || [...metrics].every((metric) => this._loaded.has(metric))) {
+        if ([...metrics].every((metric) => this._loaded.has(metric))) {
+            return;
+        }
+        // queued, so that the buffers of the engine still are the ones of the current statistics:
+        // they are read after every action
+        await this.enqueue(async () => {
+            const backend = this._backend;
+            const requested = this.requestedMetrics();
+            if (!backend || [...requested].every((metric) => this._loaded.has(metric))) {
                 return;
             }
-        // the buffers of the engine still are the ones of the current statistics, as they are
-        // read after every action
             const statistics = { ...get(this._store) };
-        this.readMetrics(wasm, statistics, metrics);
+            await this.readMetrics(backend, statistics, requested);
             this._store.set(statistics);
+        });
     }
 }

website/src/lib/engine/storage.ts

@@ -1,7 +1,7 @@
 import { LEGACY_IMPORTED_KEY, readLegacyData } from '$lib/storage/legacy-import';
 import { parseVisibility, VISIBILITY_KEY, type Visibility } from '$lib/engine/file-visibility';
 import type { Outcome, StorageOpened } from 'gpx-rs';
-import type { Wasm } from './convert';
+import type { Backend } from './backend';
 
 /** Name of the IndexedDB database that keeps the files and the settings. */
 const STORAGE_NAME = 'gpx-studio';
@@ -11,7 +11,7 @@ const CHANNEL_NAME = 'gpx-studio-storage';
 
 /** What opening the storage needs of the engine facade. */
 export type StorageHost = {
-    wasm: Wasm;
+    backend: Backend;
     /** The explicit visibility per file, to fill with the one that was saved. */
     visibility: Map<string, Visibility>;
     /** Applies what a call changed to what the facade keeps of the files. */
@@ -34,11 +34,11 @@ function followOtherTabs(host: StorageHost): {
     behind: () => void;
     newer: () => void;
 } {
-    const { wasm } = host;
+    const { backend } = host;
     let reading = Promise.resolve();
     const refresh = () => {
         reading = reading
-            .then(async () => host.sync(await wasm.sync_storage()))
+            .then(async () => host.sync(await backend.sync_storage()))
             .catch((error) => console.error('The files could not be read again', error));
     };
     const channel =
@@ -61,17 +61,17 @@ function followOtherTabs(host: StorageHost): {
 }
 
 /**
- * Opens the storage of the browser: the files that it holds are put in the engine, and the
+ * Opens the storage: the files that it holds are put in the engine, and the
  * changes of the files are kept from then on. Resolves to the settings, as JSON strings by key.
  *
  * The first time, what the previous versions of the app kept in the browser is imported.
  */
 export async function openStoredFiles(host: StorageHost): Promise<Record<string, string>> {
-    const { wasm } = host;
+    const { backend } = host;
     let opened: StorageOpened;
     const tabs = followOtherTabs(host);
     try {
-        opened = await wasm.open_storage(STORAGE_NAME, tabs.saved, tabs.behind, tabs.newer);
+        opened = await backend.open_storage(STORAGE_NAME, tabs.saved, tabs.behind, tabs.newer);
     } catch (error) {
         console.error('The files cannot be kept in this browser', error);
         return {};
@@ -83,16 +83,20 @@ export async function openStoredFiles(host: StorageHost): Promise<Record<string,
     );
     host.sync(opened.outcome);
 
-    if (settings[LEGACY_IMPORTED_KEY] === undefined && !host.hasFiles()) {
+    if (
+        backend.importsLegacyData &&
+        settings[LEGACY_IMPORTED_KEY] === undefined &&
+        !host.hasFiles()
+    ) {
         settings = { ...settings, ...(await importLegacyData(host)) };
-        await wasm.flush_storage();
+        await backend.flush_storage();
     }
     return settings;
 }
 
 /** Puts the files and the settings of the former database in the engine. */
 async function importLegacyData(host: StorageHost): Promise<Record<string, string>> {
-    const { wasm } = host;
+    const { backend } = host;
     const imported: Record<string, string> = {};
     try {
         const legacy = await readLegacyData();
@@ -108,7 +112,7 @@ async function importLegacyData(host: StorageHost): Promise<Record<string, strin
                 await host.deselect();
             }
             for (const [key, value] of Object.entries(legacy.settings)) {
-                wasm.set_setting(key, value);
+                await backend.set_setting(key, value);
                 imported[key] = value;
             }
         }
@@ -117,7 +121,7 @@ async function importLegacyData(host: StorageHost): Promise<Record<string, strin
         console.error('The files of the previous version could not be imported', error);
         return imported;
     }
-    wasm.set_setting(LEGACY_IMPORTED_KEY, 'true');
+    await backend.set_setting(LEGACY_IMPORTED_KEY, 'true');
     imported[LEGACY_IMPORTED_KEY] = 'true';
     return imported;
 }

website/src/lib/engine/types.ts

@@ -229,7 +229,7 @@ export type SelectionStatistics = {
      * the part of the elevation profile that was dragged over. `undefined` if the range is not
      * in the selection, or if the selection is not the current one anymore.
      */
-    slice(start: number, end: number): GlobalStatistics | undefined;
+    slice(start: number, end: number): Promise<GlobalStatistics | undefined>;
 };
 
 export const EMPTY_SELECTION_STATISTICS: SelectionStatistics = {
@@ -240,12 +240,12 @@ export const EMPTY_SELECTION_STATISTICS: SelectionStatistics = {
     lng: new Float64Array(),
     lat: new Float64Array(),
     ele: new Float64Array(),
-    slice: () => undefined,
+    slice: async () => undefined,
 };
 
 export type StatisticsRequest = {
-    /** Replaces the metrics needed by this consumer. */
-    set(metrics: Iterable<StatisticsMetric>): void;
+    /** Replaces the metrics needed by this consumer. Resolves when the missing ones are read. */
+    set(metrics: Iterable<StatisticsMetric>): Promise<void>;
     /** The consumer does not need any metric anymore. */
     release(): void;
 };