Welcome screen with recent repositories and a folder picker when gites starts outside a repository

src-tauri/src/git.rs

@@ -1,5 +1,5 @@
 use serde::Serialize;
-use std::path::Path;
+use std::path::{Path, PathBuf};
 use std::process::Command;
 
 #[derive(Serialize)]
@@ -130,3 +130,45 @@ pub fn load(dir: &Path) -> Result<RepoData, String> {
 
     Ok(RepoData { root, commits, refs, head_ref, head })
 }
+
+/// The repository to open at start: the path given on the command line, or else the
+/// current folder if it is inside a repository. `None` means gites starts with its
+/// welcome screen. A path given on the command line is used even if it is not a
+/// repository, so the window can say what is wrong with it.
+pub fn start_dir(arg: Option<PathBuf>, cwd: PathBuf) -> Option<PathBuf> {
+    arg.or_else(|| git(&cwd, &["rev-parse", "--git-dir"]).ok().map(|_| cwd))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn temp_dir(name: &str) -> PathBuf {
+        let dir = std::env::temp_dir().join(format!("gites-start-{name}-{}", std::process::id()));
+        let _ = std::fs::remove_dir_all(&dir);
+        std::fs::create_dir_all(&dir).unwrap();
+        dir
+    }
+
+    #[test]
+    fn opens_the_path_given_on_the_command_line_even_if_it_is_not_a_repository() {
+        let given = PathBuf::from("/no/such/folder");
+        assert_eq!(start_dir(Some(given.clone()), temp_dir("arg")), Some(given));
+    }
+
+    #[test]
+    fn opens_the_current_folder_when_it_is_inside_a_repository() {
+        let dir = temp_dir("repo");
+        git(&dir, &["init", "-q"]).unwrap();
+        std::fs::create_dir_all(dir.join("sub")).unwrap();
+        assert_eq!(start_dir(None, dir.join("sub")), Some(dir.join("sub")));
+        let _ = std::fs::remove_dir_all(&dir);
+    }
+
+    #[test]
+    fn opens_nothing_when_the_current_folder_is_not_in_a_repository() {
+        let dir = temp_dir("plain");
+        assert_eq!(start_dir(None, dir.clone()), None);
+        let _ = std::fs::remove_dir_all(&dir);
+    }
+}

src-tauri/src/lib.rs

@@ -7,32 +7,36 @@ mod settings;
 use std::path::PathBuf;
 use std::sync::Mutex;
 
-/// The open repository folder. It starts as the first command line argument, or the
-/// current folder, and changes when the user opens another one.
-struct RepoDir(Mutex<PathBuf>);
+/// The open repository folder, from `git::start_dir`; it changes when the user opens
+/// another one. `None` until a repository is open: the window shows its welcome screen.
+struct RepoDir(Mutex<Option<PathBuf>>);
 
 impl RepoDir {
-    fn get(&self) -> PathBuf {
-        self.0.lock().unwrap_or_else(|e| e.into_inner()).clone()
+    fn get(&self) -> Result<PathBuf, String> {
+        self.0.lock().unwrap_or_else(|e| e.into_inner()).clone().ok_or_else(|| "no repository is open".into())
     }
 }
 
+/// The open repository, or `None` when there is none yet.
 #[tauri::command]
-fn load_repo(dir: tauri::State<RepoDir>) -> Result<git::RepoData, String> {
-    git::load(&dir.get())
+fn load_repo(dir: tauri::State<RepoDir>) -> Result<Option<git::RepoData>, String> {
+    match dir.get() {
+        Ok(d) => git::load(&d).map(Some),
+        Err(_) => Ok(None),
+    }
 }
 
 /// Switches to another repository. The current one stays open if `path` is not a repository.
 #[tauri::command]
 fn open_repo(dir: tauri::State<RepoDir>, path: String) -> Result<git::RepoData, String> {
     let data = git::load(&PathBuf::from(&path))?;
-    *dir.0.lock().unwrap_or_else(|e| e.into_inner()) = PathBuf::from(&path);
+    *dir.0.lock().unwrap_or_else(|e| e.into_inner()) = Some(PathBuf::from(&path));
     Ok(data)
 }
 
 #[tauri::command]
 fn commit_details(dir: tauri::State<RepoDir>, hash: String) -> Result<details::CommitDetails, String> {
-    details::load(&dir.get(), &hash)
+    details::load(&dir.get()?, &hash)
 }
 
 #[tauri::command]
@@ -43,7 +47,7 @@ fn file_diff(
     old_path: Option<String>,
     force: bool,
 ) -> Result<diff::FileDiff, String> {
-    diff::load(&dir.get(), &hash, &path, old_path.as_deref(), force)
+    diff::load(&dir.get()?, &hash, &path, old_path.as_deref(), force)
 }
 
 #[tauri::command]
@@ -68,10 +72,9 @@ fn save_settings(value: serde_json::Value) -> Result<(), String> {
 
 #[cfg_attr(mobile, tauri::mobile_entry_point)]
 pub fn run() {
-    let path = std::env::args_os()
-        .nth(1)
-        .map(PathBuf::from)
-        .unwrap_or_else(|| std::env::current_dir().unwrap_or_else(|_| PathBuf::from(".")));
+    let arg = std::env::args_os().nth(1).map(PathBuf::from);
+    let cwd = std::env::current_dir().unwrap_or_else(|_| PathBuf::from("."));
+    let path = git::start_dir(arg, cwd);
 
     tauri::Builder::default()
         .plugin(tauri_plugin_clipboard_manager::init())