Improved prefix handling + per-profile prefixes

Author: yungcomputerchair

src-tauri/src/lib.rs

@@ -666,40 +666,34 @@ async fn prep_launch(
 
         #[cfg(not(target_os = "windows"))]
         {
-            // The compat data dir is, in order of priority:
-            // 1. WINEPREFIX env var in the launch command, if set
-            // 2. WINEPREFIX env var in the current environment, if set
-            // 3. The default compat data dir in the app cache
-            let mut compat_data_dir = None;
-            for env_var in cmd.get_envs() {
-                if let (key, Some(value)) = env_var {
-                    if key == "WINEPREFIX" {
-                        compat_data_dir = Some(value.into());
-                    }
-                }
-            }
-
-            if compat_data_dir.is_none() && env::var("WINEPREFIX").is_ok_and(|val| !val.is_empty())
-            {
-                compat_data_dir = Some(env::var("WINEPREFIX").unwrap().into());
-            }
-
+            // Prefix setup
+            let mut compat_data_dir = util::get_compat_data_dir(&cmd);
             if compat_data_dir.is_none() {
-                compat_data_dir = Some(app_statics.compat_data_dir.clone());
+                // not specified; use launcher compat data dir
+                let mut launcher_compat_dir = app_statics.compat_data_dir.clone();
+                launcher_compat_dir.push(profile.get_id().to_string());
+
+                if cmd.get_program().to_string_lossy().ends_with("proton") {
+                    cmd.env(
+                        "STEAM_COMPAT_DATA_PATH",
+                        launcher_compat_dir.to_string_lossy().to_string(),
+                    );
+                    // proton sets WINEPREFIX internally
+                } else {
+                    // assume wine
+                    cmd.env(
+                        "WINEPREFIX",
+                        launcher_compat_dir.to_string_lossy().to_string(),
+                    );
+                }
+                compat_data_dir = Some(launcher_compat_dir);
             }
 
             let compat_data_dir = compat_data_dir.unwrap();
             if !compat_data_dir.exists() {
+                debug!("Creating prefix at {}", compat_data_dir.to_string_lossy());
                 std::fs::create_dir_all(&compat_data_dir)?;
             }
-
-            #[cfg(target_os = "linux")]
-            {
-                if !protontools::is_device_steam_deck() {
-                    // we want to let Proton set this itself on Deck
-                    cmd.env("WINEPREFIX", compat_data_dir.to_string_lossy().to_string());
-                }
-            }
         }
 
         // Detach stdio so the child doesn't crash from broken pipes

src-tauri/src/util.rs

@@ -104,6 +104,43 @@ pub(crate) fn get_default_offline_cache_dir() -> String {
         .to_string()
 }
 
+fn get_env_var_value(cmd: &Command, var: &str) -> Option<String> {
+    // Check vars on command first
+    for env_var in cmd.get_envs() {
+        if let (key, Some(value)) = env_var {
+            let value = value.to_string_lossy().to_string();
+            if key == var && !value.is_empty() {
+                return Some(value);
+            }
+        }
+    }
+
+    // Check env
+    if let Ok(value) = env::var(var) {
+        if !value.is_empty() {
+            return Some(value);
+        }
+    }
+
+    None
+}
+
+pub(crate) fn get_compat_data_dir(cmd: &Command) -> Option<PathBuf> {
+    if cfg!(target_os = "windows") {
+        return None;
+    }
+
+    if let Some(path) = get_env_var_value(cmd, "STEAM_COMPAT_DATA_PATH") {
+        return Some(PathBuf::from(path));
+    }
+
+    if let Some(path) = get_env_var_value(cmd, "WINEPREFIX") {
+        return Some(PathBuf::from(path));
+    }
+
+    None
+}
+
 #[cfg(target_os = "macos")]
 fn find_macos_wine_installs() -> Vec<(String, PathBuf)> {
     const CANDIDATES: [&str; 5] = [
@@ -154,7 +191,6 @@ pub(crate) fn get_preset_launch_profiles() -> Vec<LaunchProfile> {
     #[cfg(target_os = "linux")]
     {
         // Find Proton installs
-        let steam_compat_data_path = get_app_statics().compat_data_dir.clone();
         if let Some(steam_compat_client_install_path) = protontools::get_steam_client_path() {
             for proton_install in protontools::find_all_proton_installs() {
                 let proton_path = proton_install.get_exe_path();
@@ -167,12 +203,12 @@ pub(crate) fn get_preset_launch_profiles() -> Vec<LaunchProfile> {
                 profiles.push(LaunchProfile::new(
                     &profile_name,
                     &format!(
-                        "STEAM_COMPAT_DATA_PATH=\"{}\" STEAM_COMPAT_CLIENT_INSTALL_PATH=\"{}\" \"{}\" run {{}}",
-                        steam_compat_data_path.to_string_lossy(),
+                        "STEAM_COMPAT_CLIENT_INSTALL_PATH=\"{}\" \"{}\" run {{}}",
                         steam_compat_client_install_path.to_string_lossy(),
                         proton_path.to_string_lossy()
-                ),
-                true));
+                    ),
+                    true,
+                ));
             }
         }
     }