clarify filename

gpx-rs/src/api/commands.rs

@@ -183,8 +183,8 @@ pub fn load_files<H: History>(
 }
 
 /// Brings changes of the files from the outside in (see [`engine::SyncFiles`]): each file is
-/// `(id, data, name)`, and replaces the file of that id, or is added if there is none. The files to
-/// `remove` are deleted. The selection is left alone.
+/// `(id, data, name)`, and replaces the file of that id, or is added if there is none; it is called
+/// `name`, whatever its data says. The files to `remove` are deleted. The selection is left alone.
 pub fn sync_files<H: History>(
     engine: &mut Engine<H>,
     files: &[(Uuid, &[u8], &str)],
@@ -232,6 +232,18 @@ pub fn reorder<H: History>(engine: &mut Engine<H>, file_ids_: &[Uuid], index: us
     )
 }
 
+/// Names a file in all its states, as if it had always been called so (not undoable): for a file
+/// that is written to a file of another name, whose name it takes.
+pub fn rename_file<H: History>(engine: &mut Engine<H>, file_id: Uuid, name: &str) -> Outcome {
+    execute(
+        engine,
+        Action::Rename {
+            file_id: engine::FileId(file_id),
+            name: name.to_owned(),
+        },
+    )
+}
+
 /// Puts the selected elements in the clipboard. Nothing happens when nothing is selected.
 pub fn copy<H: History>(engine: &mut Engine<H>) -> Outcome {
     execute(engine, Action::Copy)

gpx-rs/src/engine/action.rs

@@ -36,4 +36,11 @@ pub enum Action<'a> {
         file_ids: Vec<FileId>,
         index: usize,
     },
+    /// Names a file in all the states of the history, as if it had always been called so (see
+    /// [`crate::History::rename`]). Not undoable: for a file that is given a name from the outside,
+    /// like the name of the file it is written to.
+    Rename {
+        file_id: FileId,
+        name: String,
+    },
 }

gpx-rs/src/engine/command/file/sync.rs

@@ -7,7 +7,8 @@ use crate::{Apply, CommandError, FileId, Load, State};
 pub struct ExternalFile<'a> {
     pub id: FileId,
     pub data: &'a [u8],
-    /// Name of the file when the data has none (see [`Load`]).
+    /// Name of the file outside (the name of the file on the disk, without its extension), which
+    /// is its name here whatever the data says: a file has a single name.
     pub name: &'a str,
 }
 
@@ -15,7 +16,8 @@ pub struct ExternalFile<'a> {
 /// that are given replace the ones of the same id (which stay where they are in the order, and keep
 /// their id), or are added at the end if there are none; the ones to `remove` are deleted.
 ///
-/// Unlike [`crate::LoadFiles`], the selection is left alone (what it holds of a file that was
+/// Unlike [`crate::LoadFiles`], the files are named as they are outside (see [`ExternalFile`]), and
+/// the selection is left alone (what it holds of a file that was
 /// replaced or deleted is dropped by the engine afterwards, as with any edit).
 ///
 /// The files that cannot be read are skipped, and the files that are here stay as they are. It is an
@@ -38,6 +40,9 @@ impl Apply for SyncFiles<'_> {
             match load.parse(state.categories) {
                 Ok(mut file) => {
                     file.id = external.id;
+                    if !external.name.trim().is_empty() {
+                        file.info.name = external.name.to_owned();
+                    }
                     if state.files.insert(external.id, Rc::new(file)).is_none() {
                         state.order.0.push(external.id);
                     }
@@ -101,7 +106,8 @@ mod tests {
         .apply(&mut fx.state())
         .unwrap();
         assert_eq!(fx.order.0, [first, second]);
-        assert_eq!(fx.files[&first].info.name, "from disk");
+        // named as it is outside, not as the data says
+        assert_eq!(fx.files[&first].info.name, "name");
         assert_eq!(fx.files[&first].id, first);
         // the selection is not changed
         assert_eq!(fx.selected_files(), [second].into());

gpx-rs/src/engine/mod.rs

@@ -248,6 +248,7 @@ impl<H: History> Engine<H> {
                 self.order.move_files(&file_ids, index);
                 None
             }
+            Action::Rename { file_id, name } => self.history.rename(file_id, &name),
         };
         let changed = diff.is_some()
             || self.selection != selection_before

gpx-rs/src/engine/state/history/global.rs

@@ -1,6 +1,6 @@
 use std::rc::Rc;
 
-use super::{Diff, Files, History, diff_between};
+use super::{Diff, Files, History, Renamer, diff_between};
 use crate::{CommandError, FileId};
 
 /// One history for the whole workspace: each entry is a state of all the files.
@@ -123,6 +123,22 @@ impl History for GlobalHistory {
             None => !self.entries.is_empty(),
         }
     }
+
+    fn rename(&mut self, id: FileId, name: &str) -> Option<Diff> {
+        let before = self.current()?.get(&id)?.clone();
+        let mut renamer = Renamer::new(name);
+        for entry in self.entries.iter_mut() {
+            if let Some(file) = entry.get(&id) {
+                let renamed = renamer.rename(file);
+                entry.insert(id, renamed);
+            }
+        }
+        let after = self.current()?.get(&id)?;
+        (!Rc::ptr_eq(&before, after)).then(|| Diff {
+            modified: vec![id],
+            ..Default::default()
+        })
+    }
 }
 
 #[cfg(test)]

gpx-rs/src/engine/state/history/mod.rs

@@ -57,6 +57,41 @@ pub trait History: Default + Debug {
 
     /// Whether [`History::redo`] would do something for these `files`.
     fn can_redo(&self, files: &[FileId]) -> bool;
+
+    /// Names a file `name` in all its states, as if it had always been called so: there is nothing
+    /// to undo. Says that the file changed, `None` if there is no such file or it is called so.
+    fn rename(&mut self, id: FileId, name: &str) -> Option<Diff>;
+}
+
+/// Names the states of a file: the ones that were shared stay shared (a state that several
+/// entries have is renamed once), and the ones that are called so already are kept.
+pub(super) struct Renamer<'a> {
+    name: &'a str,
+    renamed: HashMap<*const File, Rc<File>>,
+}
+
+impl<'a> Renamer<'a> {
+    pub(super) fn new(name: &'a str) -> Self {
+        Self {
+            name,
+            renamed: HashMap::new(),
+        }
+    }
+
+    pub(super) fn rename(&mut self, file: &Rc<File>) -> Rc<File> {
+        if file.info.name == self.name {
+            return file.clone();
+        }
+        let name = self.name;
+        self.renamed
+            .entry(Rc::as_ptr(file))
+            .or_insert_with(|| {
+                let mut renamed = (**file).clone();
+                renamed.info.name = name.to_owned();
+                Rc::new(renamed)
+            })
+            .clone()
+    }
 }
 
 /// Which files were added, removed or modified by a change of the current files.

gpx-rs/src/engine/state/history/per_file.rs

@@ -1,6 +1,6 @@
 use std::rc::Rc;
 
-use super::{Diff, Files, History, diff_between};
+use super::{Diff, Files, History, Renamer, diff_between};
 use crate::{CommandError, File, FileId};
 
 use std::collections::HashMap;
@@ -139,6 +139,20 @@ impl History for PerFileHistory {
         self.any(files, FileHistory::can_undo)
     }
 
+    fn rename(&mut self, id: FileId, name: &str) -> Option<Diff> {
+        let history = self.stacks.get_mut(&id)?;
+        let mut renamer = Renamer::new(name);
+        for entry in history.entries.iter_mut() {
+            *entry = renamer.rename(entry);
+        }
+        let current = history.current().clone();
+        let before = self.current.insert(id, current.clone());
+        (!before.is_some_and(|before| Rc::ptr_eq(&before, &current))).then(|| Diff {
+            modified: vec![id],
+            ..Default::default()
+        })
+    }
+
     fn can_redo(&self, files: &[FileId]) -> bool {
         self.any(files, FileHistory::can_redo)
     }

gpx-rs/src/engine/tests.rs

@@ -182,6 +182,52 @@ fn test_metadata_renames_selected_file() {
     assert_eq!(file.info.desc.as_deref(), Some("about"));
 }
 
+#[test]
+fn test_rename_names_every_state_of_the_file_and_is_not_undoable() {
+    let mut engine = TestEngine::default();
+    new(&mut engine, "first");
+    new(&mut engine, "other");
+    let id = engine.order()[0];
+    let other = engine.order()[1];
+    let other_file = engine.history.current().unwrap()[&other].clone();
+    engine.run(Action::Select {
+        selection: Selection::File {
+            file_ids: [id].into(),
+        },
+        mode: SelectMode::Replace,
+    });
+    assert!(edit(
+        &mut engine,
+        Command::Metadata(Metadata {
+            name: "edited",
+            desc: "",
+        })
+    ));
+    assert!(engine.run(Action::Rename {
+        file_id: id,
+        name: "written".to_owned(),
+    }));
+    assert_eq!(engine.last_diff().unwrap().modified, vec![id]);
+    assert_eq!(engine.file_structure(&id).unwrap().name, "written");
+    // nothing to undo for it: the edits before are undone, and the file keeps its name
+    engine.run(Action::Undo);
+    engine.run(Action::Undo);
+    assert_eq!(engine.file_structure(&id).unwrap().name, "written");
+    engine.run(Action::Redo);
+    engine.run(Action::Redo);
+    assert_eq!(engine.file_structure(&id).unwrap().name, "written");
+    // the other file is still the same object, in every state
+    assert!(Rc::ptr_eq(
+        &engine.history.current().unwrap()[&other],
+        &other_file
+    ));
+    // naming it as it is already called changes nothing
+    assert!(!engine.run(Action::Rename {
+        file_id: id,
+        name: "written".to_owned(),
+    }));
+}
+
 #[test]
 fn test_metadata_without_selection_does_not_modify_files() {
     let mut engine = TestEngine::default();
@@ -1469,6 +1515,31 @@ mod per_file_history {
         engine.file_structure(&id).unwrap().name.clone()
     }
 
+    #[test]
+    fn test_rename_names_every_state_of_the_file() {
+        let mut engine = Engine::<PerFileHistory>::default();
+        let id = new_file(&mut engine, "a");
+        select(&mut engine, &[id]);
+        rename(&mut engine, "b");
+        rename(&mut engine, "c");
+        let outcome = engine
+            .execute(Action::Rename {
+                file_id: id,
+                name: "written".to_owned(),
+            })
+            .unwrap();
+        assert_eq!(outcome.diff.unwrap().modified, vec![id]);
+        assert_eq!(name_of(&engine, id), "written");
+        // the edits are still there to undo, the name stays
+        engine.execute(Action::Undo).unwrap();
+        assert!(engine.can_undo());
+        engine.execute(Action::Undo).unwrap();
+        assert!(!engine.can_undo());
+        assert_eq!(name_of(&engine, id), "written");
+        engine.execute(Action::Redo).unwrap();
+        assert_eq!(name_of(&engine, id), "written");
+    }
+
     #[test]
     fn test_creating_a_file_is_not_undoable() {
         let mut engine = Engine::<PerFileHistory>::default();

tauri/src/commands/disk.rs

@@ -113,10 +113,8 @@ fn write_unsaved<R: Runtime>(
     state.core(move |core| {
         let result = core
             .workspace
-            .save(&core.engine, &ids, &chosen, folder.as_deref());
-        core.keep_workspace();
-        core.announce(None);
-        result.map(|()| true)
+            .save(&mut core.engine, &ids, &chosen, folder.as_deref());
+        core.wrote(result)
     })
 }
 
@@ -180,10 +178,8 @@ pub fn save_file_as<R: Runtime>(
         return Ok(false);
     };
     state.core(move |core| {
-        let result = core.workspace.save_as(&core.engine, file_id, &path);
-        core.keep_workspace();
-        core.announce(None);
-        result.map(|()| true)
+        let result = core.workspace.save_as(&mut core.engine, file_id, &path);
+        core.wrote(result)
     })
 }
 

tauri/src/commands/edit.rs

@@ -1,15 +1,28 @@
 //! 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::{CleanType, MergeType, SplitType, api};
+use gpx_engine::{CleanType, FileId, MergeType, Selection, SplitType, api};
 use tauri::State;
 use uuid::Uuid;
 
 use crate::state::AppState;
 
+/// Names and describes the selected files or tracks. A file on the disk is renamed with it (and back
+/// when it is undone): its name is one that a file can have, and not the one of another file.
 #[tauri::command(async)]
 pub fn metadata(state: State<AppState>, name: String, desc: String) -> api::Outcome {
-    state.run(move |e| api::metadata(e, &name, &desc))
+    state.core(move |core| {
+        let mut name = name;
+        if let Selection::File { file_ids } = core.engine.selection() {
+            for FileId(id) in file_ids.clone() {
+                name = core.workspace.valid_name(id, &name);
+                if let Err(error) = core.workspace.renamed_path(id, &name) {
+                    return api::Outcome::failed(error);
+                }
+            }
+        }
+        core.edit(move |e| api::metadata(e, &name, &desc))
+    })
 }
 
 #[tauri::command(async)]

tauri/src/commands/files.rs

@@ -109,10 +109,10 @@ pub fn move_elements(
 
 #[tauri::command(async)]
 pub fn undo(state: State<AppState>) -> api::Outcome {
-    state.run(api::undo)
+    state.edit(api::undo)
 }
 
 #[tauri::command(async)]
 pub fn redo(state: State<AppState>) -> api::Outcome {
-    state.run(api::redo)
+    state.edit(api::redo)
 }

tauri/src/state.rs

@@ -96,6 +96,48 @@ impl Core {
         self.announce(None);
     }
 
+    /// Runs `f` on the engine, which can change: what changed is kept, and the files on the disk are
+    /// renamed like the files of the engine were (an edit of the name, or its undo). Gives what
+    /// could not be renamed.
+    fn editing<T>(&mut self, f: impl FnOnce(&mut Engine) -> T) -> (T, Vec<String>) {
+        let names = self.workspace.names(&self.engine);
+        let result = f(&mut self.engine);
+        let (renamed, errors) = self.workspace.follow_names(&mut self.engine, &names);
+        if renamed {
+            self.keep_workspace();
+            self.announce(None);
+        }
+        self.persist();
+        (result, errors)
+    }
+
+    /// Like `editing`, for an edit that can rename files: the outcome tells the first thing that
+    /// could not be renamed (a key of the dictionaries of the frontend, which shows it).
+    pub fn edit(&mut self, f: impl FnOnce(&mut Engine) -> api::Outcome) -> api::Outcome {
+        let (outcome, errors) = self.editing(f);
+        match errors.first() {
+            Some(error) if !outcome.has_error() => {
+                outcome.merge(api::Outcome::failed(error.clone()))
+            }
+            _ => outcome,
+        }
+    }
+
+    /// After files were written (`result`): what changed in the engine (the files are called like
+    /// the files they were written to) is kept and told, with where the files are. Says whether
+    /// they were written.
+    pub fn wrote(&mut self, result: Result<api::Outcome, String>) -> Result<bool, String> {
+        self.keep_workspace();
+        match &result {
+            Ok(outcome) if outcome.changed => {
+                self.persist();
+                self.announce(Some(outcome));
+            }
+            _ => self.announce(None),
+        }
+        result.map(|_| true)
+    }
+
     /// Writes the workspace, and watches what it holds (a file may have been opened or closed).
     pub fn keep_workspace(&mut self) {
         self.workspace.write(self.storage.root());
@@ -228,11 +270,13 @@ impl Core {
                     Some((id, source.map(|(_, display)| display.clone())))
                 })
                 .collect();
-            if let Err(error) = self.workspace.save_new(&self.engine, &made)
-                && !outcome.has_error()
-            {
+            match self.workspace.save_new(&mut self.engine, &made) {
+                Ok(renamed) => outcome = outcome.merge(renamed),
+                Err(error) if !outcome.has_error() => {
                     outcome = outcome.merge(api::Outcome::failed(error));
                 }
+                Err(_) => {}
+            }
         }
         self.keep_workspace();
         self.persist();
@@ -291,15 +335,25 @@ impl AppState {
         result.recv().expect("the engine thread stopped")
     }
 
-    /// Runs `f` on the engine, which can change: what changed is kept.
+    /// Runs `f` on the engine, which can change: what changed is kept (see `Core::editing`).
     pub fn run<T: Send + 'static>(&self, f: impl FnOnce(&mut Engine) -> T + Send + 'static) -> T {
         self.core(move |core| {
-            let result = f(&mut core.engine);
-            core.persist();
+            let (result, errors) = core.editing(f);
+            for error in errors {
+                eprintln!("{error}");
+            }
             result
         })
     }
 
+    /// Like `run`, for an edit that can rename files: the outcome tells what could not be renamed.
+    pub fn edit(
+        &self,
+        f: impl FnOnce(&mut Engine) -> api::Outcome + Send + 'static,
+    ) -> api::Outcome {
+        self.core(move |core| core.edit(f))
+    }
+
     /// Reads from the engine.
     pub fn read<T: Send + 'static>(&self, f: impl FnOnce(&Engine) -> T + Send + 'static) -> T {
         self.core(move |core| f(&core.engine))

tauri/src/tests.rs

@@ -396,7 +396,7 @@ fn files_are_opened_closed_and_made_in_a_folder() {
 
     // closing: what is saved goes, what has edits stays unless it is discarded
     app.call("select", json!({ "fileIds": [new_id], "mode": "replace" }));
-    app.call("metadata", json!({ "name": "edited", "desc": "" }));
+    app.call("style", json!({ "color": "#ff0000" }));
     app.call("close_files", json!({ "fileIds": [id, new_id] }));
     assert_eq!(app.call("file_order", json!({})), json!([new_id]));
     app.call(
@@ -550,3 +550,123 @@ fn files_can_be_reordered() {
         json!([ids[2], ids[0], ids[1]])
     );
 }
+
+/// A folder of its own, with GPX files whose name inside is not the name of the file.
+fn folder_with(files: &[&str]) -> std::path::PathBuf {
+    let folder = std::env::temp_dir().join(format!("gpx-names-{}", uuid::Uuid::new_v4()));
+    std::fs::create_dir_all(&folder).unwrap();
+    for name in files {
+        std::fs::write(
+            folder.join(format!("{name}.gpx")),
+            r#"<?xml version="1.0"?><gpx version="1.1" creator="test"><metadata><name>Inside</name></metadata><trk><trkseg><trkpt lat="50.0" lon="4.0"></trkpt><trkpt lat="50.1" lon="4.1"></trkpt></trkseg></trk></gpx>"#,
+        )
+        .unwrap();
+    }
+    folder
+}
+
+fn name_of(app: &App, id: &str) -> String {
+    app.call("file_structure", json!({ "fileId": id }))["name"]
+        .as_str()
+        .unwrap()
+        .to_string()
+}
+
+#[test]
+fn a_file_is_called_like_its_file_and_renaming_it_renames_the_file() {
+    let app = App::new();
+    let folder = folder_with(&["outside", "taken"]);
+    let outcome = app.call(
+        "open_paths",
+        json!({ "paths": [folder.join("outside.gpx")] }),
+    );
+    let id = outcome["added"][0].as_str().unwrap().to_string();
+
+    // the name in the file is not the name of the file: the file wins, and nothing is unsaved
+    assert_eq!(name_of(&app, &id), "outside");
+    assert_eq!(
+        app.call("workspace_state", json!({}))["files"][&id]["dirty"],
+        false
+    );
+
+    // renaming renames the file on the disk
+    app.call("select", json!({ "fileIds": [id], "mode": "replace" }));
+    let outcome = app.call("metadata", json!({ "name": "renamed", "desc": "" }));
+    assert!(outcome.get("error").is_none());
+    assert!(folder.join("renamed.gpx").exists());
+    assert!(!folder.join("outside.gpx").exists());
+    let path = app.call("workspace_state", json!({}))["files"][&id]["path"].clone();
+    assert!(path.as_str().unwrap().ends_with("renamed.gpx"));
+    // the file had nothing unsaved: it is written with its new name, and still has nothing unsaved
+    let dirty = |app: &App| app.call("workspace_state", json!({}))["files"][&id]["dirty"].clone();
+    let inside = |name: &str| std::fs::read_to_string(folder.join(format!("{name}.gpx"))).unwrap();
+    assert_eq!(dirty(&app), false);
+    assert!(inside("renamed").contains("<name>renamed</name>"));
+
+    // undone and redone, on the disk too, still with nothing unsaved
+    app.call("undo", json!({}));
+    assert_eq!(name_of(&app, &id), "outside");
+    assert!(folder.join("outside.gpx").exists() && !folder.join("renamed.gpx").exists());
+    assert_eq!(dirty(&app), false);
+    assert!(inside("outside").contains("<name>outside</name>"));
+    app.call("redo", json!({}));
+    assert_eq!(name_of(&app, &id), "renamed");
+    assert!(folder.join("renamed.gpx").exists() && !folder.join("outside.gpx").exists());
+    assert_eq!(dirty(&app), false);
+
+    // the name of another file is not taken, nothing changes
+    let outcome = app.call("metadata", json!({ "name": "taken", "desc": "" }));
+    assert_eq!(outcome["error"], crate::workspace::NAME_TAKEN);
+    assert_eq!(name_of(&app, &id), "renamed");
+    assert!(folder.join("renamed.gpx").exists());
+
+    // a name is one that a file can have
+    app.call("metadata", json!({ "name": "a/b", "desc": "" }));
+    assert_eq!(name_of(&app, &id), "a_b");
+    assert!(folder.join("a_b.gpx").exists());
+
+    // a file with edits is renamed, but not written: its edits are not saved for it
+    app.call("style", json!({ "color": "#ff0000" }));
+    assert_eq!(dirty(&app), true);
+    app.call("metadata", json!({ "name": "edited", "desc": "" }));
+    assert!(folder.join("edited.gpx").exists());
+    assert_eq!(dirty(&app), true);
+    assert!(!inside("edited").contains("ff0000"));
+    app.call("undo", json!({}));
+    app.call("undo", json!({}));
+    assert_eq!(name_of(&app, &id), "a_b");
+    assert_eq!(dirty(&app), false);
+
+    // only the case changes: the same file
+    app.call("metadata", json!({ "name": "A_B", "desc": "" }));
+    assert_eq!(name_of(&app, &id), "A_B");
+    let names: Vec<String> = std::fs::read_dir(&folder)
+        .unwrap()
+        .map(|entry| entry.unwrap().file_name().to_string_lossy().into_owned())
+        .collect();
+    assert!(names.contains(&"A_B.gpx".to_string()));
+    assert_eq!(names.len(), 2);
+    std::fs::remove_dir_all(folder).unwrap();
+}
+
+#[test]
+fn a_new_file_written_under_another_name_takes_it() {
+    let app = App::new();
+    let folder = folder_with(&["route"]);
+    // a new file made in the folder is written there at once: route.gpx is taken
+    let created = app.call(
+        "new_file",
+        json!({ "name": "route", "lng": 4.4, "lat": 50.8, "folder": folder }),
+    );
+    let id = created["added"][0].as_str().unwrap().to_string();
+    assert!(folder.join("route (2).gpx").exists());
+    assert_eq!(name_of(&app, &id), "route (2)");
+    assert_eq!(
+        app.call("workspace_state", json!({}))["files"][&id]["dirty"],
+        false
+    );
+    // which is not an edit to undo
+    app.call("select", json!({ "fileIds": [id], "mode": "replace" }));
+    assert_eq!(app.call("can_undo", json!({})), false);
+    std::fs::remove_dir_all(folder).unwrap();
+}

tauri/src/workspace.rs

@@ -58,6 +58,12 @@ pub fn signature(engine: &Engine, id: Uuid) -> Option<u64> {
     Some(hash(&serde_json::to_vec(&structure).ok()?))
 }
 
+/// A file cannot be renamed: another one has the name. The errors that the frontend shows are keys
+/// of its dictionaries (`website/src/locales`).
+pub const NAME_TAKEN: &str = "menu.metadata.name_taken";
+/// A file cannot be renamed on the disk.
+pub const RENAME_FAILED: &str = "menu.metadata.rename_failed";
+
 /// What to do with the files that have unsaved edits when they are closed.
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Deserialize)]
 #[serde(rename_all = "camelCase")]
@@ -211,6 +217,23 @@ fn file_name(name: &str) -> String {
     }
 }
 
+/// Whether two paths are the same file (two cases of a name, on a disk that does not tell them
+/// apart).
+fn same_file(a: &Path, b: &Path) -> bool {
+    #[cfg(unix)]
+    {
+        use std::os::unix::fs::MetadataExt;
+        matches!(
+            (fs::metadata(a), fs::metadata(b)),
+            (Ok(a), Ok(b)) if (a.dev(), a.ino()) == (b.dev(), b.ino())
+        )
+    }
+    #[cfg(not(unix))]
+    {
+        matches!((fs::canonicalize(a), fs::canonicalize(b)), (Ok(a), Ok(b)) if a == b)
+    }
+}
+
 fn stem(path: &Path) -> String {
     path.file_stem()
         .map(|stem| stem.to_string_lossy().into_owned())
@@ -617,15 +640,16 @@ impl Workspace {
 
     /// Writes files to the disk, replacing what is there: they are the same as their file from
     /// then on. A file that is not on the disk goes in its folder, or at its path in `paths`, or in
-    /// `folder`, under its name (changed if that is the one of something else). Stops at the first
-    /// error, the files that were written stay written.
+    /// `folder`, under its name (changed if that is the one of something else), which the file then
+    /// has (see `write_file`). Stops at the first error, the files that were written stay written.
     pub fn save(
         &mut self,
-        engine: &Engine,
+        engine: &mut Engine,
         ids: &[Uuid],
         paths: &BTreeMap<Uuid, PathBuf>,
         folder: Option<&Path>,
-    ) -> Result<(), String> {
+    ) -> Result<api::Outcome, String> {
+        let mut outcome = api::Outcome::failed_none();
         for id in ids {
             let Some(structure) = engine.file_structure(&FileId(*id)) else {
                 continue;
@@ -638,20 +662,20 @@ impl Workspace {
                 (None, None, None, Some(dir)) => in_folder(dir),
                 (None, None, None, None) => continue,
             };
-            self.write_file(engine, *id, &path)?;
+            outcome = outcome.merge(self.write_file(engine, *id, &path)?);
         }
-        Ok(())
+        Ok(outcome)
     }
 
     /// Writes the new files among `files` in their folder, each under the name that is given (the
     /// name in the file when there is none). A name that is the one of something else is changed
     /// (`name (2)`). Files that would be called the same, like the parts of a split, are numbered
-    /// from 1 (`name (1)`, `name (2)`).
+    /// from 1 (`name (1)`, `name (2)`). The files are called like the file they are written to.
     pub fn save_new(
         &mut self,
-        engine: &Engine,
+        engine: &mut Engine,
         files: &[(Uuid, Option<String>)],
-    ) -> Result<(), String> {
+    ) -> Result<api::Outcome, String> {
         let names: Vec<Option<(Uuid, PathBuf, String)>> = files
             .iter()
             .map(|(id, name)| {
@@ -664,6 +688,7 @@ impl Workspace {
                 ))
             })
             .collect();
+        let mut outcome = api::Outcome::failed_none();
         for entry in &names {
             let Some((id, dir, name)) = entry else {
                 continue;
@@ -681,9 +706,106 @@ impl Workspace {
             } else {
                 free_path(dir, name, |p| self.is_taken(p))
             };
-            self.write_file(engine, *id, &path)?;
+            outcome = outcome.merge(self.write_file(engine, *id, &path)?);
         }
-        Ok(())
+        Ok(outcome)
+    }
+
+    /// The names of the files that are on the disk, and whether they are the files on the disk, to
+    /// tell which ones were renamed by an edit (see `follow_names`).
+    pub fn names(&self, engine: &Engine) -> BTreeMap<Uuid, (String, bool)> {
+        self.links
+            .keys()
+            .filter_map(|id| {
+                let name = engine.file_structure(&FileId(*id))?.name.clone();
+                Some((*id, (name, !self.is_dirty(engine, *id))))
+            })
+            .collect()
+    }
+
+    /// The name that a file on the disk can have: the name of a file, without its extension (see
+    /// `file_name`). Others are given to the files that are not on the disk yet when they are
+    /// written.
+    pub fn valid_name(&self, id: Uuid, name: &str) -> String {
+        if self.links.contains_key(&id) {
+            file_name(name)
+        } else {
+            name.to_owned()
+        }
+    }
+
+    /// Where a file on the disk goes when it is called `name`: next to where it is, with the same
+    /// extension. `None` if it is there already, an error if something else is.
+    pub fn renamed_path(&self, id: Uuid, name: &str) -> Result<Option<PathBuf>, String> {
+        let Some(link) = self.links.get(&id) else {
+            return Ok(None);
+        };
+        let extension = link
+            .path
+            .extension()
+            .map(|extension| extension.to_string_lossy().into_owned())
+            .unwrap_or_else(|| "gpx".to_owned());
+        let path = link
+            .path
+            .with_file_name(format!("{}.{extension}", file_name(name)));
+        if path == link.path {
+            return Ok(None);
+        }
+        // the same file under another case, on a disk that does not tell them apart, is not another
+        let other = self
+            .links
+            .iter()
+            .any(|(other, l)| *other != id && l.path == path)
+            || (path.exists() && !same_file(&path, &link.path));
+        if other {
+            return Err(NAME_TAKEN.to_owned());
+        }
+        Ok(Some(path))
+    }
+
+    /// Renames the files on the disk whose name changed in the engine since it had `before` (see
+    /// `names`): an edit of the name, or its undo, renames the file. A file that was the one on the
+    /// disk is written too, so that it still is: the rename is not something to save. A file with
+    /// edits is not, its edits are not saved for it. A file that cannot be renamed keeps its place,
+    /// with the reason in the errors. Says whether a file was renamed.
+    pub fn follow_names(
+        &mut self,
+        engine: &mut Engine,
+        before: &BTreeMap<Uuid, (String, bool)>,
+    ) -> (bool, Vec<String>) {
+        let mut renamed = false;
+        let mut errors = vec![];
+        for (id, (old, clean)) in before {
+            let Some(structure) = engine.file_structure(&FileId(*id)) else {
+                continue;
+            };
+            if structure.name == *old {
+                continue;
+            }
+            let path = match self.renamed_path(*id, &structure.name) {
+                Ok(Some(path)) => path,
+                Ok(None) => continue,
+                Err(error) => {
+                    errors.push(error);
+                    continue;
+                }
+            };
+            let link = self.links.get_mut(id).expect("the file is on the disk");
+            // a file that is gone is written at its new place when it is saved
+            if !link.missing
+                && let Err(error) = fs::rename(&link.path, &path)
+            {
+                eprintln!("{} cannot be renamed: {error}", link.path.display());
+                errors.push(RENAME_FAILED.to_owned());
+                continue;
+            }
+            link.path = path.clone();
+            renamed = true;
+            if *clean && let Err(error) = self.write_file(engine, *id, &path) {
+                errors.push(error);
+            }
+        }
+        (renamed, errors)
     }
 
     /// The name of a file as the user knows it: the name of the file on the disk, without its
@@ -696,7 +818,12 @@ impl Workspace {
     }
 
     /// Writes a file to a path of the user's choice, which is the place of the file from then on.
-    pub fn save_as(&mut self, engine: &Engine, id: Uuid, path: &Path) -> Result<(), String> {
+    pub fn save_as(
+        &mut self,
+        engine: &mut Engine,
+        id: Uuid,
+        path: &Path,
+    ) -> Result<api::Outcome, String> {
         if let Some(other) = self.id_of(&canonical(path))
             && other != id
         {
@@ -705,13 +832,30 @@ impl Workspace {
         self.write_file(engine, id, path)
     }
 
-    fn write_file(&mut self, engine: &Engine, id: Uuid, path: &Path) -> Result<(), String> {
+    /// Writes a file to `path`, which it is linked to from then on. It is called like the file it is
+    /// written to (a file has a single name), as if it always had been: that is not an edit to
+    /// undo. Says what changed in the engine.
+    fn write_file(
+        &mut self,
+        engine: &mut Engine,
+        id: Uuid,
+        path: &Path,
+    ) -> Result<api::Outcome, String> {
+        let Some(structure) = engine.file_structure(&FileId(id)) else {
+            return Ok(api::Outcome::failed_none());
+        };
+        let name = stem(path);
+        let renamed = if structure.name != name {
+            api::rename_file(engine, id, &name)
+        } else {
+            api::Outcome::failed_none()
+        };
         let Some(bytes) = api::export_file(engine, id, ExportOptions::ALL) else {
-            return Ok(());
+            return Ok(renamed);
         };
         write_atomically(path, &bytes).map_err(|error| format!("{}: {error}", path.display()))?;
         let Some(signature) = signature(engine, id) else {
-            return Ok(());
+            return Ok(renamed);
         };
         // the folder, if there is one, may watch what was just written: the hash tells it is known
         self.links.insert(
@@ -726,7 +870,7 @@ impl Workspace {
             },
         );
         self.dirs.remove(&id);
-        Ok(())
+        Ok(renamed)
     }
 
     /// The folders and the GPX files that are in a folder of the open folder (or in it), the
@@ -776,7 +920,7 @@ mod tests {
 
     fn gpx(name: &str) -> String {
         format!(
-            r#"<?xml version="1.0"?><gpx version="1.1" creator="test" xmlns="http://www.topografix.com/GPX/1/1"><metadata><name>{name}</name></metadata><trk><trkseg><trkpt lat="50.0" lon="4.0"><ele>10</ele></trkpt><trkpt lat="50.1" lon="4.1"><ele>20</ele></trkpt></trkseg></trk></gpx>"#
+            r#"<?xml version="1.0"?><gpx version="1.1" creator="test" xmlns="http://www.topografix.com/GPX/1/1"><metadata><name>{name}</name></metadata><trk><name>{name}</name><trkseg><trkpt lat="50.0" lon="4.0"><ele>10</ele></trkpt><trkpt lat="50.1" lon="4.1"><ele>20</ele></trkpt></trkseg></trk></gpx>"#
         )
     }
 
@@ -833,7 +977,7 @@ mod tests {
 
         fn save(&mut self, ids: &[Uuid]) {
             self.workspace
-                .save(&self.engine, ids, &BTreeMap::new(), None)
+                .save(&mut self.engine, ids, &BTreeMap::new(), None)
                 .unwrap();
         }
 
@@ -856,6 +1000,14 @@ mod tests {
                 .clone()
         }
 
+        /// What the file holds: the name of its track (its own name is the one of the file).
+        fn content(&self, id: Uuid) -> String {
+            self.engine.file_structure(&FileId(id)).unwrap().tracks[0]
+                .name
+                .clone()
+                .unwrap_or_default()
+        }
+
         fn rename(&mut self, id: Uuid, name: &str) {
             api::select(&mut self.engine, &[id], SelectMode::Replace);
             assert!(!api::metadata(&mut self.engine, name, "").has_error());
@@ -919,7 +1071,9 @@ mod tests {
 
         let path = fx.folder.join("fresh.gpx");
         let paths = BTreeMap::from([(id, path.clone())]);
-        fx.workspace.save(&fx.engine, &[id], &paths, None).unwrap();
+        fx.workspace
+            .save(&mut fx.engine, &[id], &paths, None)
+            .unwrap();
         assert!(path.exists());
         assert!(!fx.workspace.is_dirty(&fx.engine, id));
         assert!(fx.workspace.unlinked(&fx.engine, &[id]).is_empty());
@@ -935,7 +1089,7 @@ mod tests {
         let ids = fx.ids();
         let folder = fx.folder.clone();
         fx.workspace
-            .save(&fx.engine, &ids, &BTreeMap::new(), Some(&folder))
+            .save(&mut fx.engine, &ids, &BTreeMap::new(), Some(&folder))
             .unwrap();
         for name in ["fresh (2).gpx", "fresh (3).gpx", "a_b_ c.gpx"] {
             assert!(fx.folder.join(name).exists(), "{name}");
@@ -949,11 +1103,11 @@ mod tests {
         let path = fx.write("a.gpx", "a");
         fx.open_folder();
         let id = fx.ids()[0];
-        fx.rename(id, "renamed");
+        api::select(&mut fx.engine, &[id], SelectMode::Replace);
+        assert!(!api::style(&mut fx.engine, Some("#ff0000"), None, None).has_error());
         fx.save(&[id]);
         assert!(fx.reconcile(Some(&[path])).is_none());
-        assert!(!fx.status(id).replaced);
-        assert_eq!(fx.name(id), "renamed");
+        assert!(!fx.status(id).replaced && !fx.status(id).dirty);
     }
 
     #[test]
@@ -1076,7 +1230,7 @@ mod tests {
         assert!(outcome.changed);
         // the same file, now the one on the disk
         assert_eq!(fx.ids(), [id]);
-        assert_eq!(fx.name(id), "theirs");
+        assert_eq!(fx.content(id), "theirs");
         let status = fx.status(id);
         assert!(!status.dirty && !status.replaced);
         // looking again changes nothing
@@ -1119,13 +1273,13 @@ mod tests {
         assert!(fx.status(id).replaced);
 
         fx.workspace.reload(&mut fx.engine, &[id]).unwrap();
-        assert_eq!(fx.name(id), "theirs");
+        assert_eq!(fx.content(id), "theirs");
         let status = fx.status(id);
         assert!(!status.dirty && !status.replaced);
         // and it is one undo step
         api::select(&mut fx.engine, &[id], SelectMode::Replace);
         api::undo(&mut fx.engine);
-        assert_eq!(fx.name(id), "mine");
+        assert_eq!(fx.content(id), "mine");
     }
 
     #[test]
@@ -1176,7 +1330,7 @@ mod tests {
 
         fx.write("a.gpx", "back");
         fx.reconcile(None);
-        assert_eq!(fx.name(id), "back");
+        assert_eq!(fx.content(id), "back");
         let status = fx.status(id);
         assert!(!status.dirty && !status.missing);
     }
@@ -1189,7 +1343,7 @@ mod tests {
         let id = fx.ids()[0];
         fx.write("a.gpx", "changed");
         assert!(fx.reconcile(None).is_some());
-        assert_eq!(fx.name(id), "changed");
+        assert_eq!(fx.content(id), "changed");
         fs::remove_file(a).unwrap();
         assert!(fx.reconcile(None).is_some());
         assert!(fx.status(id).missing);
@@ -1360,7 +1514,9 @@ mod tests {
         // the place of the file is taken by a folder
         fs::remove_file(fx.folder.join("a.gpx")).unwrap();
         fs::create_dir(fx.folder.join("a.gpx")).unwrap();
-        let result = fx.workspace.save(&fx.engine, &[id], &BTreeMap::new(), None);
+        let result = fx
+            .workspace
+            .save(&mut fx.engine, &[id], &BTreeMap::new(), None);
         assert!(result.is_err());
         assert!(fx.workspace.is_dirty(&fx.engine, id));
     }
@@ -1376,7 +1532,7 @@ mod tests {
         fx.rename(id, "edited");
 
         let target = fx.folder.join("copy.gpx");
-        fx.workspace.save_as(&fx.engine, id, &target).unwrap();
+        fx.workspace.save_as(&mut fx.engine, id, &target).unwrap();
         assert!(fs::read_to_string(&target).unwrap().contains("edited"));
         assert!(fs::read_to_string(a).unwrap().contains(">a<"));
         let status = fx.status(id);
@@ -1385,7 +1541,7 @@ mod tests {
 
         // the place of another open file is not available
         let taken = fx.folder.join("b.gpx");
-        assert!(fx.workspace.save_as(&fx.engine, id, &taken).is_err());
+        assert!(fx.workspace.save_as(&mut fx.engine, id, &taken).is_err());
         assert!(!fx.workspace.is_dirty(&fx.engine, other));
     }
 }

website/src/lib/components/file-list/metadata/MetadataDialog.svelte

@@ -9,6 +9,8 @@
     import { editMetadata } from '$lib/components/file-list/metadata/utils.svelte';
     import { engine, type FileState } from '$lib/engine';
     import type { FileTreeNode } from '$lib/engine/selection-helpers';
+    import { toast } from 'svelte-sonner';
+    import { get } from 'svelte/store';
 
     let {
         fileState,
@@ -53,8 +55,15 @@
                 // would open the dialog again before the effect below has reset it
                 editMetadata.current = false;
                 open = false;
-                // the metadata of the selected elements are changed
-                engine.metadata(name, description);
+                // the metadata of the selected elements are changed. In the desktop app, a file on
+                // the disk is renamed with it, which is refused if the name is the one of another
+                engine.metadata(name, description).then((changed) => {
+                    const error = get(engine.lastError);
+                    if (!changed && error !== undefined && error !== 'nothing to do') {
+                        // a key of the dictionaries, when it comes from the desktop app
+                        toast.error(i18n._(error, error));
+                    }
+                });
             }}
         >
             <Save size="16" />

website/src/locales/en.json

@@ -87,7 +87,9 @@
             "button": "Info...",
             "name": "Name",
             "description": "Description",
-            "save": "Save"
+            "save": "Save",
+            "name_taken": "A file with this name already exists in the folder.",
+            "rename_failed": "The file could not be renamed."
         },
         "style": {
             "button": "Appearance...",