feat(linux) add with_temp_icon_dir builder extension (#452)

* linux: Defer writing files to the `SystemTrayBuilder::build` call

* linux: Add an argument to `temp_icon_path` for a custom directory

* linux: Add `temp_icon_dir` field to the `SystemTrayBuilder`

* linux: Add `with_temp_icon_dir` builder method

* linux: Use `with_temp_icon_dir` in `system_tray` example

* Add changes file

* Format with cargo fmt

Rather than rust analyzer

.changes/linux-custom-temp-icon-dir.md

@@ -0,0 +1,6 @@
+---
+"tao": minor
+---
+
+On Linux, adds `SystemTrayBuilderExtLinux::with_temp_icon_dir` which sets a custom temp icon dir to store generated icon files.
+This may be useful when the application requires icons to be stored in a specific location, such as when running in a Flatpak sandbox.

examples/system_tray.rs

@@ -6,6 +6,8 @@
 #[cfg(any(target_os = "windows", target_os = "linux", target_os = "macos"))]
 #[cfg(any(feature = "tray", all(target_os = "linux", feature = "ayatana")))]
 fn main() {
+  #[cfg(target_os = "linux")]
+  use tao::platform::linux::SystemTrayBuilderExtLinux;
   #[cfg(target_os = "macos")]
   use tao::platform::macos::{CustomMenuItemExtMacOS, NativeImage, SystemTrayBuilderExtMacOS};
   use tao::{
@@ -30,6 +32,13 @@ fn main() {
 
   let icon = load_icon(std::path::Path::new(path));
 
+  #[cfg(target_os = "linux")]
+  let system_tray = SystemTrayBuilder::new(icon, Some(tray_menu))
+    .with_temp_icon_dir(std::path::Path::new("/tmp/tao-examples"))
+    .build(&event_loop)
+    .unwrap();
+
+  #[cfg(not(target_os = "linux"))]
   let system_tray = SystemTrayBuilder::new(icon, Some(tray_menu))
     .build(&event_loop)
     .unwrap();

src/platform/linux.rs

@@ -0,0 +1,23 @@
+// Copyright 2019-2021 Tauri Programme within The Commons Conservancy
+// SPDX-License-Identifier: Apache-2.0
+
+#![cfg(target_os = "linux")]
+
+#[cfg(feature = "tray")]
+use crate::system_tray::SystemTrayBuilder;
+#[cfg(feature = "tray")]
+use std::path::Path;
+
+#[cfg(feature = "tray")]
+pub trait SystemTrayBuilderExtLinux {
+  /// Sets a custom temp icon dir to store generated icon files.
+  fn with_temp_icon_dir<P: AsRef<Path>>(self, p: P) -> Self;
+}
+
+#[cfg(feature = "tray")]
+impl SystemTrayBuilderExtLinux for SystemTrayBuilder {
+  fn with_temp_icon_dir<P: AsRef<Path>>(mut self, p: P) -> Self {
+    self.0.temp_icon_dir = Some(p.as_ref().to_path_buf());
+    self
+  }
+}

src/platform/mod.rs

@@ -9,6 +9,7 @@
 //!  - `ios`
 //!  - `macos`
 //!  - `unix`
+//!  - `linux`
 //!  - `windows`
 //!
 //! And the following platform-specific module:
@@ -20,6 +21,7 @@
 
 pub mod android;
 pub mod ios;
+pub mod linux;
 pub mod macos;
 pub mod run_return;
 pub mod unix;

src/platform_impl/linux/system_tray.rs

@@ -16,54 +16,58 @@ use libappindicator::{AppIndicator, AppIndicatorStatus};
 use super::{menu::Menu, window::WindowRequest, WindowId};
 
 pub struct SystemTrayBuilder {
+  pub(crate) temp_icon_dir: Option<PathBuf>,
   tray_menu: Option<Menu>,
-  app_indicator: AppIndicator,
-  path: PathBuf,
+  icon: Icon,
 }
 
 impl SystemTrayBuilder {
   #[inline]
   pub fn new(icon: Icon, tray_menu: Option<Menu>) -> Self {
-    let (parent_path, icon_path) =
-      temp_icon_path().expect("Failed to create a temp folder for icon");
-    icon.inner.write_to_png(&icon_path);
-
-    let mut app_indicator = AppIndicator::new("tao application", "");
-    app_indicator.set_icon_theme_path(&parent_path.to_string_lossy());
-    app_indicator.set_icon_full(&icon_path.to_string_lossy(), "icon");
-
     Self {
+      temp_icon_dir: None,
       tray_menu,
-      app_indicator,
-      path: icon_path,
+      icon,
     }
   }
 
   #[inline]
   pub fn build<T: 'static>(
-    mut self,
+    self,
     window_target: &EventLoopWindowTarget<T>,
   ) -> Result<RootSystemTray, OsError> {
+    let mut app_indicator = AppIndicator::new("tao application", "");
+
+    let (parent_path, icon_path) =
+      temp_icon_path(self.temp_icon_dir.as_ref()).expect("Failed to create a temp folder for icon");
+
+    self.icon.inner.write_to_png(&icon_path);
+
+    app_indicator.set_icon_theme_path(&parent_path.to_string_lossy());
+    app_indicator.set_icon_full(&icon_path.to_string_lossy(), "icon");
+
     let sender = window_target.p.window_requests_tx.clone();
 
     if let Some(tray_menu) = self.tray_menu.clone() {
       let menu = &mut tray_menu.into_gtkmenu(&sender, &AccelGroup::new(), WindowId::dummy());
 
-      self.app_indicator.set_menu(menu);
+      app_indicator.set_menu(menu);
       menu.show_all();
     }
 
-    self.app_indicator.set_status(AppIndicatorStatus::Active);
+    app_indicator.set_status(AppIndicatorStatus::Active);
 
     Ok(RootSystemTray(SystemTray {
-      app_indicator: self.app_indicator,
+      temp_icon_dir: self.temp_icon_dir,
+      app_indicator,
       sender,
-      path: self.path,
+      path: icon_path,
     }))
   }
 }
 
 pub struct SystemTray {
+  temp_icon_dir: Option<PathBuf>,
   app_indicator: AppIndicator,
   sender: Sender<(WindowId, WindowRequest)>,
   path: PathBuf,
@@ -72,7 +76,7 @@ pub struct SystemTray {
 impl SystemTray {
   pub fn set_icon(&mut self, icon: Icon) {
     let (parent_path, icon_path) =
-      temp_icon_path().expect("Failed to create a temp folder for icon");
+      temp_icon_path(self.temp_icon_dir.as_ref()).expect("Failed to create a temp folder for icon");
     icon.inner.write_to_png(&icon_path);
 
     self
@@ -101,28 +105,38 @@ impl Drop for SystemTray {
   }
 }
 
-fn temp_icon_path() -> std::io::Result<(PathBuf, PathBuf)> {
-  let mut parent_path = dirs_next::runtime_dir().unwrap_or_else(|| std::env::temp_dir());
+/// Generates an icon path in one of the following dirs:
+/// 1. If `temp_icon_dir` is `Some` use that.
+/// 2. `$XDG_RUNTIME_DIR/tao`
+/// 3. `/tmp/tao`
+fn temp_icon_path(temp_icon_dir: Option<&PathBuf>) -> std::io::Result<(PathBuf, PathBuf)> {
+  let parent_path = match temp_icon_dir.as_ref() {
+    Some(path) => path.to_path_buf(),
+    None => dirs_next::runtime_dir()
+      .unwrap_or_else(|| std::env::temp_dir())
+      .join("tao"),
+  };
 
-  parent_path.push("tao");
   std::fs::create_dir_all(&parent_path)?;
-  let mut icon_path = parent_path.clone();
-  icon_path.push(format!("tray-icon-{}.png", uuid::Uuid::new_v4()));
+  let icon_path = parent_path.join(format!("tray-icon-{}.png", uuid::Uuid::new_v4()));
   Ok((parent_path, icon_path))
 }
 
 #[test]
-fn temp_icon_path_prefers_runtime() {
+fn temp_icon_path_preference_order() {
   let runtime_dir = option_env!("XDG_RUNTIME_DIR");
+  let override_dir = PathBuf::from("/tmp/tao-tests");
 
-  let (dir1, _file1) = temp_icon_path().unwrap();
+  let (dir1, _file1) = temp_icon_path(Some(&override_dir)).unwrap();
+  let (dir2, _file1) = temp_icon_path(None).unwrap();
   std::env::remove_var("XDG_RUNTIME_DIR");
-  let (dir2, _file2) = temp_icon_path().unwrap();
+  let (dir3, _file2) = temp_icon_path(None).unwrap();
 
+  assert_eq!(dir1, override_dir);
   if let Some(runtime_dir) = runtime_dir {
     std::env::set_var("XDG_RUNTIME_DIR", runtime_dir);
-    assert_eq!(dir1, PathBuf::from(format!("{}/tao", runtime_dir)));
+    assert_eq!(dir2, PathBuf::from(format!("{}/tao", runtime_dir)));
   }
 
-  assert_eq!(dir2, PathBuf::from("/tmp/tao"));
+  assert_eq!(dir3, PathBuf::from("/tmp/tao"));
 }