Initial commit

breadlock-ui/src/desktop_entry.rs

@@ -0,0 +1,134 @@
+//! Minimal freedesktop `.desktop` entry parsing — just enough to discover
+//! session launchers (`Name=`, `Exec=`, `Type=`) under
+//! `/usr/share/wayland-sessions` and `/usr/share/xsessions`. BOS only ships
+//! one session today, so this deliberately doesn't handle the full spec
+//! (localized `Name[xx]=`, `Exec=` quoting/field codes, `Actions=`, etc.) —
+//! only the three keys a greeter needs to list and launch a session.
+
+use std::path::Path;
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct DesktopEntry {
+    pub name: String,
+    pub exec: String,
+    pub entry_type: String,
+}
+
+/// Parses the `[Desktop Entry]` section of a `.desktop` file's contents.
+/// Returns `None` if `Name=` or `Exec=` is missing.
+pub fn parse(contents: &str) -> Option<DesktopEntry> {
+    let mut name = None;
+    let mut exec = None;
+    let mut entry_type = None;
+    let mut in_desktop_entry = false;
+
+    for line in contents.lines() {
+        let line = line.trim();
+        if line.is_empty() || line.starts_with('#') {
+            continue;
+        }
+        if let Some(section) = line.strip_prefix('[').and_then(|s| s.strip_suffix(']')) {
+            in_desktop_entry = section == "Desktop Entry";
+            continue;
+        }
+        if !in_desktop_entry {
+            continue;
+        }
+        if let Some((key, value)) = line.split_once('=') {
+            match key.trim() {
+                "Name" => name = Some(value.trim().to_string()),
+                "Exec" => exec = Some(value.trim().to_string()),
+                "Type" => entry_type = Some(value.trim().to_string()),
+                _ => {}
+            }
+        }
+    }
+
+    Some(DesktopEntry {
+        name: name?,
+        exec: exec?,
+        entry_type: entry_type.unwrap_or_else(|| "Application".to_string()),
+    })
+}
+
+/// Scans a directory for `*.desktop` files, returning `(file stem, entry)`
+/// pairs. Unreadable directories and unparsable entries are silently skipped
+/// — a missing session directory is normal (e.g. no X11 sessions installed).
+pub fn scan_dir(dir: &Path) -> Vec<(String, DesktopEntry)> {
+    let Ok(read_dir) = std::fs::read_dir(dir) else {
+        return Vec::new();
+    };
+
+    let mut entries: Vec<(String, DesktopEntry)> = read_dir
+        .filter_map(|e| e.ok())
+        .filter(|e| e.path().extension().is_some_and(|ext| ext == "desktop"))
+        .filter_map(|e| {
+            let stem = e.path().file_stem()?.to_str()?.to_string();
+            let contents = std::fs::read_to_string(e.path()).ok()?;
+            Some((stem, parse(&contents)?))
+        })
+        .collect();
+
+    entries.sort_by(|a, b| a.0.cmp(&b.0));
+    entries
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    const HYPRLAND_DESKTOP: &str = "[Desktop Entry]\n\
+        Name=Hyprland\n\
+        Comment=An intelligent dynamic tiling Wayland compositor\n\
+        Exec=Hyprland\n\
+        Type=Application\n";
+
+    #[test]
+    fn parses_name_exec_type() {
+        let e = parse(HYPRLAND_DESKTOP).unwrap();
+        assert_eq!(e.name, "Hyprland");
+        assert_eq!(e.exec, "Hyprland");
+        assert_eq!(e.entry_type, "Application");
+    }
+
+    #[test]
+    fn ignores_keys_outside_desktop_entry_section() {
+        let contents = "[Desktop Action foo]\nName=Not this one\n\
+            [Desktop Entry]\nName=Real\nExec=real-cmd\n";
+        let e = parse(contents).unwrap();
+        assert_eq!(e.name, "Real");
+        assert_eq!(e.exec, "real-cmd");
+    }
+
+    #[test]
+    fn missing_exec_returns_none() {
+        assert!(parse("[Desktop Entry]\nName=Broken\n").is_none());
+    }
+
+    #[test]
+    fn missing_type_defaults_to_application() {
+        let e = parse("[Desktop Entry]\nName=X\nExec=x\n").unwrap();
+        assert_eq!(e.entry_type, "Application");
+    }
+
+    #[test]
+    fn scan_dir_on_missing_directory_returns_empty() {
+        assert!(scan_dir(Path::new("/nonexistent/wayland-sessions")).is_empty());
+    }
+
+    #[test]
+    fn scan_dir_finds_and_sorts_desktop_files() {
+        let dir = std::env::temp_dir().join("breadlock-ui-test-sessions");
+        std::fs::create_dir_all(&dir).unwrap();
+        std::fs::write(dir.join("zzz.desktop"), HYPRLAND_DESKTOP).unwrap();
+        std::fs::write(dir.join("aaa.desktop"), "[Desktop Entry]\nName=A\nExec=a\n").unwrap();
+        std::fs::write(dir.join("not-a-session.txt"), "ignored").unwrap();
+
+        let found = scan_dir(&dir);
+        assert_eq!(found.len(), 2);
+        assert_eq!(found[0].0, "aaa");
+        assert_eq!(found[1].0, "zzz");
+
+        std::fs::remove_dir_all(&dir).ok();
+    }
+}