Use XDG_DATA_DIRS to find graphical sessions

Cargo.toml

@@ -17,6 +17,7 @@ nix = { version = "0.30", features = ["signal"] }
 async-global-executor = "3.0.0"
 futures-util = "0.3.30"
 log = "0.4.22"
+lazy_static = "^1.4"
 
 [dependencies.glib]
 version = "0.18"

src/sessions.rs

@@ -3,25 +3,58 @@ use glib::warn;
 use glob::glob;
 use gtk::gio::DesktopAppInfo;
 use gtk::prelude::*;
-use std::collections::HashMap;
+use lazy_static::lazy_static;
+use std::{
+  collections::HashMap,
+  path::PathBuf,
+  path::Path,
+  env,
+};
 
 static G_LOG_DOMAIN: &str = "phrog-sessions";
 
+lazy_static! {
+    // Snippet copied from https://github.com/apognu/tuigreet
+
+    static ref XDG_DATA_DIRS: Vec<PathBuf> = {
+        let envvar = env::var("XDG_DATA_DIRS");
+
+        let value = match envvar {
+            Ok(var) if !var.is_empty() => var,
+            _ => "/usr/local/share:/usr/share".to_string(),
+        };
+
+        env::split_paths(&value).filter(|p| p.is_absolute()).collect()
+    };
+}
+
 pub fn sessions() -> Vec<SessionObject> {
     let mut sessions = HashMap::new();
-    session_list(
-        "/usr/share/wayland-sessions/*.desktop",
-        "wayland",
-        &mut sessions,
-    );
-    session_list("/usr/share/xsessions/*.desktop", "x11", &mut sessions);
+
+    for dir in XDG_DATA_DIRS.iter() {
+        let wl_dir = dir.join("wayland-sessions/*.desktop");
+        let x11_dir = dir.join("xsessions/*.desktop");
+
+        session_list(
+            &wl_dir,
+            "wayland",
+            &mut sessions,
+        );
+
+        session_list(
+            &x11_dir,
+            "x11",
+            &mut sessions,
+        );        
+    };
+
     sessions.values().cloned().collect()
 }
 
-fn session_list(path: &str, session_type: &str, sessions: &mut HashMap<String, SessionObject>) {
-    for f in match glob(path) {
+fn session_list(path: &Path, session_type: &str, sessions: &mut HashMap<String, SessionObject>) {
+    for f in match glob(path.to_str().unwrap()) {
         Err(e) => {
-            warn!("couldn't check sessions in {}: {}", path, e);
+            warn!("couldn't check sessions in {}: {}", path.display(), e);
             return;
         }
         Ok(iter) => iter,