window: Add support for setting the app icon on the Mac.

Requires servo/cocoa-rs#124.

src/api/cocoa/mod.rs

@@ -42,6 +42,7 @@ use std::str::from_utf8;
 use std::sync::Mutex;
 use std::ascii::AsciiExt;
 use std::ops::Deref;
+use std::path::PathBuf;
 
 use events::ElementState::{Pressed, Released};
 use events::Event::{Awakened, MouseInput, MouseMoved, ReceivedCharacter, KeyboardInput};
@@ -298,7 +299,8 @@ impl Window {
             _ => ()
         }
 
-        let app = match Window::create_app(pl_attribs.activation_policy) {
+        let app = match Window::create_app(pl_attribs.activation_policy,
+                                           win_attribs.icon.clone()) {
             Some(app) => app,
             None      => { return Err(OsError(format!("Couldn't create NSApplication"))); },
         };
@@ -363,13 +365,22 @@ impl Window {
         Ok(window)
     }
 
-    fn create_app(activation_policy: ActivationPolicy) -> Option<id> {
+    fn create_app(activation_policy: ActivationPolicy, icon_path: Option<PathBuf>) -> Option<id> {
         unsafe {
             let app = NSApp();
             if app == nil {
                 None
             } else {
                 app.setActivationPolicy_(activation_policy.into());
+                if let Some(icon_path) = icon_path {
+                    if let Some(icon_path) = icon_path.to_str() {
+                        let icon_path = NSString::alloc(nil).init_str(icon_path);
+                        let icon = NSImage::alloc(nil).initByReferencingFile_(icon_path);
+                        if icon.isValid() != NO {
+                            app.setApplicationIconImage_(icon)
+                        }
+                    }
+                }
                 app.finishLaunching();
                 Some(app)
             }

src/lib.rs

@@ -69,6 +69,7 @@ pub use native_monitor::NativeMonitorId;
 use std::io;
 #[cfg(not(target_os = "macos"))]
 use std::cmp::Ordering;
+use std::path::PathBuf;
 
 mod api;
 mod platform;
@@ -551,6 +552,12 @@ pub struct WindowAttributes {
     /// (https://developer.apple.com/library/ios/documentation/UIKit/Reference/UIView_Class/#//apple_ref/occ/instp/UIView/multipleTouchEnabled)
     pub multitouch: bool,
 
+    /// A path to an icon for the window. This may not be supported on every windowing system.
+    /// If present, this path must reference a PNG file.
+    ///
+    /// The default is `None`.
+    pub icon: Option<PathBuf>,
+
     /// Parent Window.
     ///
     /// The default is `None`.
@@ -570,6 +577,7 @@ impl Default for WindowAttributes {
             transparent: false,
             decorations: true,
             multitouch: false,
+            icon: None,
             parent: None,
         }
     }

src/window.rs

@@ -1,5 +1,6 @@
 use std::collections::vec_deque::IntoIter as VecDequeIter;
 use std::default::Default;
+use std::path::PathBuf;
 
 use Api;
 use ContextError;
@@ -202,6 +203,13 @@ impl<'a> WindowBuilder<'a> {
         self
     }
 
+    /// Sets the icon for the window. The supplied path must reference a PNG file.
+    #[inline]
+    pub fn with_icon(mut self, icon_path: PathBuf) -> WindowBuilder<'a> {
+        self.window.icon = Some(icon_path);
+        self
+    }
+
     /// Sets the parent window
     pub fn with_parent(mut self, parent: Option<WindowID>) -> WindowBuilder<'a> {
         self.window.parent = parent;