refactor(linux): remove zbus and use unity launcher APIs directly (#880)

* refactor(linux): remove zbus and use unity launcher APIs directly

* change files

* fmt

---------

Co-authored-by: Lucas Nogueira <lucas@tauri.studio>

.changes/bump-msrv.md

@@ -0,0 +1,5 @@
+---
+"tao": minor
+---
+
+Updated the minimum supported Rust version to 1.70.

.changes/progress-bar-refactor.md

@@ -0,0 +1,5 @@
+---
+"tao": minor
+---
+
+Progress bar on Linux no longer relies on zbus. Changed  `ProgressBarState`'s field `unity_uri` to `desktop_filename`.

Cargo.toml

@@ -7,7 +7,7 @@ authors = [
   "The winit contributors"
 ]
 edition = "2021"
-rust-version = "1.56"
+rust-version = "1.70"
 keywords = [ "windowing" ]
 license = "Apache-2.0"
 readme = "README.md"
@@ -32,9 +32,6 @@ default = [ "rwh_06" ]
 [workspace]
 members = [ "tao-macros" ]
 
-[build-dependencies]
-cc = "1"
-
 [dependencies]
 instant = "0.1"
 lazy_static = "1"
@@ -120,6 +117,6 @@ gtk = "0.18"
 gdkx11-sys = "0.18"
 gdkwayland-sys = "0.18.0"
 x11-dl = "2.21"
-zbus = "4"
 png = "0.17"
 parking_lot = "0.12"
+dlopen2 = "0.7.0"

examples/progress_bar.rs

@@ -61,7 +61,7 @@ fn main() {
             window.set_progress_bar(ProgressBarState {
               progress: Some(progress),
               state: Some(ProgressState::Normal),
-              unity_uri: None,
+              desktop_filename: None,
             });
           } else if modifiers.control_key() {
             let mut state = ProgressState::None;
@@ -77,7 +77,7 @@ fn main() {
             window.set_progress_bar(ProgressBarState {
               progress: None,
               state: Some(state),
-              unity_uri: None,
+              desktop_filename: None,
             });
           }
         }

src/platform_impl/linux/event_loop.rs

@@ -245,8 +245,7 @@ impl<T: 'static> EventLoop<T> {
       None
     };
 
-    let mut taskbar: Option<TaskbarIndicator> = None;
-    let supports_unity = util::is_unity();
+    let mut taskbar = TaskbarIndicator::new();
 
     // Window Request
     window_requests_rx.attach(Some(&context), move |(id, request)| {
@@ -853,19 +852,7 @@ impl<T: 'static> EventLoop<T> {
       } else if id == WindowId::dummy() {
         match request {
           WindowRequest::ProgressBarState(state) => {
-            if supports_unity {
-              if taskbar.is_none() {
-                if let Ok(indicator) = TaskbarIndicator::new() {
-                  taskbar.replace(indicator);
-                }
-              }
-
-              if let Some(taskbar) = &mut taskbar {
-                if let Err(e) = taskbar.update(state) {
-                  log::warn!("Failed to update taskbar progress {}", e);
-                }
-              }
-            }
+            taskbar.update(state);
           }
           _ => unreachable!(),
         }

src/platform_impl/linux/taskbar.rs

@@ -1,56 +1,138 @@
-use crate::window::{ProgressBarState, ProgressState};
-use zbus::{
-  blocking::Connection,
-  fdo::Result,
-  zvariant::{DeserializeDict, SerializeDict, Type},
-  Message,
-};
+use std::ffi::CString;
 
-pub struct TaskbarIndicator {
-  conn: Connection,
-  app_uri: String,
+use dlopen2::wrapper::{Container, WrapperApi};
+
+use crate::window::{ProgressBarState, ProgressState};
+
+#[derive(WrapperApi)]
+struct UnityLib {
+  unity_launcher_entry_get_for_desktop_id: unsafe extern "C" fn(id: *const i8) -> *const isize,
+  unity_inspector_get_default: unsafe extern "C" fn() -> *const isize,
+  unity_inspector_get_unity_running: unsafe extern "C" fn(inspector: *const isize) -> i32,
+  unity_launcher_entry_set_progress: unsafe extern "C" fn(entry: *const isize, value: f64) -> i32,
+  unity_launcher_entry_set_progress_visible:
+    unsafe extern "C" fn(entry: *const isize, value: i32) -> i32,
 }
 
-#[derive(Default, SerializeDict, DeserializeDict, Type, PartialEq, Debug)]
-#[zvariant(signature = "dict")]
-struct Progress {
-  progress: Option<f64>,
-  #[zvariant(rename = "progress-visible")]
-  progress_visible: Option<bool>,
-  urgent: Option<bool>,
+pub struct TaskbarIndicator {
+  desktop_filename: Option<String>,
+  desktop_filename_c_str: Option<CString>,
+
+  is_supported: bool,
+  unity_lib: Option<Container<UnityLib>>,
+  attempted_load: bool,
+
+  unity_inspector: Option<*const isize>,
+  unity_entry: Option<*const isize>,
 }
 
 impl TaskbarIndicator {
-  pub fn new() -> Result<Self> {
-    let conn = Connection::session()?;
+  pub fn new() -> Self {
+    Self {
+      desktop_filename: None,
+      desktop_filename_c_str: None,
 
-    Ok(Self {
-      conn,
-      app_uri: String::new(),
-    })
+      is_supported: is_supported(),
+      unity_lib: None,
+      attempted_load: false,
+
+      unity_inspector: None,
+      unity_entry: None,
+    }
   }
 
-  pub fn update(&mut self, progress: ProgressBarState) -> Result<()> {
-    let mut properties = Progress::default();
-
-    if let Some(uri) = progress.unity_uri {
-      self.app_uri = uri;
+  fn ensure_lib_load(&mut self) {
+    if self.attempted_load {
+      return;
     }
 
-    if let Some(progress) = progress.progress {
-      let progress = if progress > 100 { 100 } else { progress };
+    self.attempted_load = true;
 
-      properties.progress = Some(progress as f64 / 100.0);
+    self.unity_lib = unsafe {
+      Container::load("libunity.so.4")
+        .or_else(|_| Container::load("libunity.so.6"))
+        .or_else(|_| Container::load("libunity.so.9"))
+        .ok()
+    };
+
+    if let Some(unity_lib) = &self.unity_lib {
+      let handle = unsafe { unity_lib.unity_inspector_get_default() };
+      if !handle.is_null() {
+        self.unity_inspector = Some(handle);
+      }
+    }
+  }
+
+  fn ensure_entry_load(&mut self) {
+    if let Some(unity_lib) = &self.unity_lib {
+      if let Some(id) = &self.desktop_filename_c_str {
+        let handle = unsafe { unity_lib.unity_launcher_entry_get_for_desktop_id(id.as_ptr()) };
+        if !handle.is_null() {
+          self.unity_entry = Some(handle);
+        }
+      }
+    }
+  }
+
+  fn is_unity_running(&self) -> bool {
+    if let Some(inspector) = self.unity_inspector {
+      if let Some(unity_lib) = &self.unity_lib {
+        return unsafe { unity_lib.unity_inspector_get_unity_running(inspector) } == 1;
+      }
     }
 
-    if let Some(state) = progress.state {
-      properties.progress_visible = Some(!matches!(state, ProgressState::None));
+    false
+  }
+
+  pub fn update(&mut self, progress: ProgressBarState) {
+    if let Some(uri) = progress.desktop_filename {
+      self.desktop_filename = Some(uri);
     }
 
-    let signal = Message::signal("/", "com.canonical.Unity.LauncherEntry", "Update")?
-      .build(&(self.app_uri.clone(), properties))?;
+    if !self.is_supported {
+      return;
+    }
 
-    self.conn.send(&signal)?;
-    Ok(())
+    self.ensure_lib_load();
+
+    if !self.is_unity_running() {
+      return;
+    }
+
+    if let Some(uri) = &self.desktop_filename {
+      self.desktop_filename_c_str = Some(CString::new(uri.as_str()).unwrap_or_default());
+    }
+
+    if self.unity_entry.is_none() {
+      self.ensure_entry_load();
+    }
+    if let Some(unity_lib) = &self.unity_lib {
+      if let Some(unity_entry) = &self.unity_entry {
+        if let Some(progress) = progress.progress {
+          let progress = if progress > 100 { 100 } else { progress };
+          let progress = progress as f64 / 100.0;
+          unsafe { (unity_lib.unity_launcher_entry_set_progress)(*unity_entry, progress) };
+        }
+
+        if let Some(state) = progress.state {
+          let is_visible = !matches!(state, ProgressState::None);
+          unsafe {
+            (unity_lib.unity_launcher_entry_set_progress_visible)(
+              *unity_entry,
+              if is_visible { 1 } else { 0 },
+            )
+          };
+        }
+      }
+    }
   }
 }
+
+pub fn is_supported() -> bool {
+  std::env::var("XDG_CURRENT_DESKTOP")
+    .map(|d| {
+      let d = d.to_lowercase();
+      d.contains("unity") || d.contains("gnome")
+    })
+    .unwrap_or(false)
+}

src/platform_impl/linux/util.rs

@@ -70,12 +70,3 @@ pub fn set_size_constraints<W: GtkWindowExt + WidgetExt>(
     geom_mask,
   )
 }
-
-pub fn is_unity() -> bool {
-  std::env::var("XDG_CURRENT_DESKTOP")
-    .map(|d| {
-      let d = d.to_lowercase();
-      d.contains("unity") || d.contains("gnome")
-    })
-    .unwrap_or(false)
-}

src/window.rs

@@ -33,8 +33,8 @@ pub struct ProgressBarState {
   pub state: Option<ProgressState>,
   /// The progress bar progress. This can be a value ranging from `0` to `100`
   pub progress: Option<u64>,
-  /// The identifier for your app to communicate with the Unity desktop window manager **Linux Only**
-  pub unity_uri: Option<String>,
+  /// The `.desktop` filename with the Unity desktop window manager, for example `myapp.desktop` **Linux Only**
+  pub desktop_filename: Option<String>,
 }
 
 /// Represents a window.