compositing: Implement cursor per CSS3-UI § 8.1.1 in the CEF/Mac port.

I'm not sure how we want to handle Linux cursors, and GLFW has no
ability to set cursors (short of disabling it and managing it yourself).

components/compositing/compositor.rs

@@ -3,8 +3,8 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 use compositor_layer::{CompositorData, CompositorLayer, WantsScrollEventsFlag};
-use compositor_task::{CompositorEventListener, CompositorProxy, CompositorReceiver, CompositorTask};
-use compositor_task::{LayerProperties, Msg};
+use compositor_task::{CompositorEventListener, CompositorProxy, CompositorReceiver};
+use compositor_task::{CompositorTask, LayerProperties, Msg};
 use constellation::{FrameId, FrameTreeDiff, SendableFrameTree};
 use pipeline::CompositionPipeline;
 use scrolling::ScrollingTimerProxy;
@@ -338,6 +338,10 @@ impl<Window: WindowMethods> IOCompositor<Window> {
                 self.window.handle_key(key, modified);
             }
 
+            (Msg::SetCursor(cursor), ShutdownState::NotShuttingDown) => {
+                self.window.set_cursor(cursor)
+            }
+
             // When we are shutting_down, we need to avoid performing operations
             // such as Paint that may crash because we have begun tearing down
             // the rest of our resources.

components/compositing/compositor_task.rs

@@ -21,6 +21,7 @@ use servo_msg::compositor_msg::{Epoch, LayerId, LayerMetadata, ReadyState};
 use servo_msg::compositor_msg::{PaintListener, PaintState, ScriptListener, ScrollPolicy};
 use servo_msg::constellation_msg::{ConstellationChan, LoadData, PipelineId};
 use servo_msg::constellation_msg::{Key, KeyState, KeyModifiers, Pressed};
+use servo_util::cursor::Cursor;
 use servo_util::memory::MemoryProfilerChan;
 use servo_util::time::TimeProfilerChan;
 use std::comm::{channel, Sender, Receiver};
@@ -213,6 +214,8 @@ pub enum Msg {
     ScrollTimeout(u64),
     /// Sends an unconsumed key event back to the compositor.
     KeyEvent(Key, KeyModifiers),
+    /// Changes the cursor.
+    SetCursor(Cursor),
 }
 
 impl Show for Msg {
@@ -231,11 +234,12 @@ impl Show for Msg {
             Msg::ChangePageTitle(..) => write!(f, "ChangePageTitle"),
             Msg::ChangePageLoadData(..) => write!(f, "ChangePageLoadData"),
             Msg::PaintMsgDiscarded(..) => write!(f, "PaintMsgDiscarded"),
+            Msg::FrameTreeUpdate(..) => write!(f, "FrameTreeUpdate"),
             Msg::SetIds(..) => write!(f, "SetIds"),
-            Msg::FrameTreeUpdate(..) => write!(f, "FrameTreeUpdateMsg"),
             Msg::LoadComplete => write!(f, "LoadComplete"),
             Msg::ScrollTimeout(..) => write!(f, "ScrollTimeout"),
             Msg::KeyEvent(..) => write!(f, "KeyEvent"),
+            Msg::SetCursor(..) => write!(f, "SetCursor"),
         }
     }
 }

components/compositing/constellation.rs

@@ -18,20 +18,21 @@ use libc;
 use script_traits::{mod, GetTitleMsg, ResizeMsg, ResizeInactiveMsg, ExitPipelineMsg, SendEventMsg};
 use script_traits::{ScriptControlChan, ScriptTaskFactory};
 use servo_msg::compositor_msg::LayerId;
-use servo_msg::constellation_msg::{ConstellationChan, ExitMsg, FailureMsg, Failure, FrameRectMsg};
-use servo_msg::constellation_msg::{GetPipelineTitleMsg};
+use servo_msg::constellation_msg::{mod, ConstellationChan, ExitMsg, FailureMsg, Failure};
+use servo_msg::constellation_msg::{FrameRectMsg, GetPipelineTitleMsg};
 use servo_msg::constellation_msg::{IFrameSandboxState, IFrameUnsandboxed, InitLoadUrlMsg};
 use servo_msg::constellation_msg::{KeyEvent, Key, KeyState, KeyModifiers, LoadCompleteMsg};
 use servo_msg::constellation_msg::{LoadData, LoadUrlMsg, NavigateMsg, NavigationType};
 use servo_msg::constellation_msg::{PainterReadyMsg, PipelineId, ResizedWindowMsg};
-use servo_msg::constellation_msg::{ScriptLoadedURLInIFrameMsg, SubpageId, WindowSizeData};
+use servo_msg::constellation_msg::{ScriptLoadedURLInIFrameMsg, SetCursorMsg, SubpageId};
+use servo_msg::constellation_msg::{WindowSizeData};
 use servo_msg::constellation_msg::Msg as ConstellationMsg;
-use servo_msg::constellation_msg;
 use servo_net::image_cache_task::{ImageCacheTask, ImageCacheTaskClient};
 use servo_net::resource_task::ResourceTask;
 use servo_net::resource_task;
 use servo_net::storage_task::StorageTask;
 use servo_net::storage_task;
+use servo_util::cursor::Cursor;
 use servo_util::geometry::{PagePx, ViewportPx};
 use servo_util::opts;
 use servo_util::task::spawn_named;
@@ -472,6 +473,7 @@ impl<LTF: LayoutTaskFactory, STF: ScriptTaskFactory> Constellation<LTF, STF> {
                                                             subpage_id,
                                                             sandbox);
             }
+            SetCursorMsg(cursor) => self.handle_set_cursor_msg(cursor),
             // Load a new page, usually -- but not always -- from a mouse click or typed url
             // If there is already a pending page (self.pending_frames), it will not be overridden;
             // However, if the id is not encompassed by another change, it will be.
@@ -754,6 +756,10 @@ impl<LTF: LayoutTaskFactory, STF: ScriptTaskFactory> Constellation<LTF, STF> {
         self.pipelines.insert(pipeline.id, pipeline);
     }
 
+    fn handle_set_cursor_msg(&mut self, cursor: Cursor) {
+        self.compositor_proxy.send(CompositorMsg::SetCursor(cursor))
+    }
+
     fn handle_load_url_msg(&mut self, source_id: PipelineId, load_data: LoadData) {
         let url = load_data.url.to_string();
         debug!("Constellation: received message to load {:s}", url);

components/compositing/headless.rs

@@ -99,10 +99,18 @@ impl CompositorEventListener for NullCompositor {
 
             Msg::CreateOrUpdateRootLayer(..) |
             Msg::CreateOrUpdateDescendantLayer(..) |
-            Msg::SetLayerOrigin(..) | Msg::Paint(..) |
-            Msg::ChangeReadyState(..) | Msg::ChangePaintState(..) | Msg::ScrollFragmentPoint(..) |
-            Msg::LoadComplete | Msg::PaintMsgDiscarded(..) | Msg::ScrollTimeout(..) | Msg::ChangePageTitle(..) |
-            Msg::ChangePageLoadData(..) | Msg::KeyEvent(..) => ()
+            Msg::SetLayerOrigin(..) |
+            Msg::Paint(..) |
+            Msg::ChangeReadyState(..) |
+            Msg::ChangePaintState(..) |
+            Msg::ScrollFragmentPoint(..) |
+            Msg::LoadComplete |
+            Msg::PaintMsgDiscarded(..) |
+            Msg::ScrollTimeout(..) |
+            Msg::ChangePageTitle(..) |
+            Msg::ChangePageLoadData(..) |
+            Msg::KeyEvent(..) |
+            Msg::SetCursor(..) => {}
         }
         true
     }

components/compositing/windowing.rs

@@ -13,6 +13,7 @@ use layers::geometry::DevicePixel;
 use layers::platform::surface::NativeGraphicsMetadata;
 use servo_msg::compositor_msg::{PaintState, ReadyState};
 use servo_msg::constellation_msg::{Key, KeyState, KeyModifiers, LoadData};
+use servo_util::cursor::Cursor;
 use servo_util::geometry::ScreenPx;
 use std::fmt::{FormatError, Formatter, Show};
 use std::rc::Rc;
@@ -124,6 +125,9 @@ pub trait WindowMethods {
     /// proceed and false if it should not.
     fn prepare_for_composite(&self) -> bool;
 
+    /// Sets the cursor to be used in the window.
+    fn set_cursor(&self, cursor: Cursor);
+
     /// Process a key event.
     fn handle_key(&self, key: Key, mods: KeyModifiers);
 }