compositor: Create a single cross-process compositor API (#33619) (#33660)

Instead of exposing many different kinds of messages to the compositor
that are routed through the constellation, expose a single message type
which can be sent across IPC channels. In addition, this IPC channel and
the route to the crossbeam channel with the compositor is created along
with the `CompositorProxy`, simplifying what needs to be passed around
during pipeline initialization.

Previously, some image updates (from video) were sent over IPC with a
special serialization routine and some were sent via crossbeam channels
(canvas). Now all updates go over the IPC channel `IpcSharedMemory` is
used to avoid serialization penalties. This should improve performance
and reduce copies for video, but add a memory copy overhead for canvas.
This will improve in the future when canvas renders directly into a
texture.

All-in-all this is a simplification which opens the path toward having a
standard compositor API and reduces the number of duplicate messages and
proxying that had to happen in libservo.

Signed-off-by: Martin Robinson <mrobinson@igalia.com>

1 files changed, 16 insertions, 16 deletions

diff --git a/components/script/dom/htmlmediaelement.rs b/components/script/dom/htmlmediaelement.rs
index 72657e5e3eb..89b1eebac78 100644
--- a/components/script/dom/htmlmediaelement.rs
+++ b/components/script/dom/htmlmediaelement.rs
@@ -17,7 +17,7 @@ use headers::{ContentLength, ContentRange, HeaderMapExt};
 use html5ever::{local_name, namespace_url, ns, LocalName, Prefix};
 use http::header::{self, HeaderMap, HeaderValue};
 use http::StatusCode;
-use ipc_channel::ipc;
+use ipc_channel::ipc::{self, IpcSharedMemory};
 use ipc_channel::router::ROUTER;
 use js::jsapi::JSAutoRealm;
 use media::{glplayer_channel, GLPlayerMsg, GLPlayerMsgForward, WindowGLContext};
@@ -35,10 +35,10 @@ use servo_media::player::{PlaybackState, Player, PlayerError, PlayerEvent, SeekL
 use servo_media::{ClientContextId, ServoMedia, SupportsMediaType};
 use servo_url::ServoUrl;
 use webrender_api::{
-    ExternalImageData, ExternalImageId, ExternalImageType, ImageBufferKind, ImageData,
-    ImageDescriptor, ImageDescriptorFlags, ImageFormat, ImageKey,
+    ExternalImageData, ExternalImageId, ExternalImageType, ImageBufferKind, ImageDescriptor,
+    ImageDescriptorFlags, ImageFormat, ImageKey,
 };
-use webrender_traits::{ImageUpdate, WebRenderScriptApi};
+use webrender_traits::{CrossProcessCompositorApi, ImageUpdate, SerializableImageData};
 
 use crate::document_loader::{LoadBlocker, LoadType};
 use crate::dom::attr::Attr;
@@ -157,7 +157,7 @@ impl FrameHolder {
 
 pub struct MediaFrameRenderer {
     player_id: Option<u64>,
-    api: WebRenderScriptApi,
+    compositor_api: CrossProcessCompositorApi,
     current_frame: Option<(ImageKey, i32, i32)>,
     old_frame: Option<ImageKey>,
     very_old_frame: Option<ImageKey>,
@@ -166,10 +166,10 @@ pub struct MediaFrameRenderer {
 }
 
 impl MediaFrameRenderer {
-    fn new(render_api_sender: WebRenderScriptApi) -> Self {
+    fn new(compositor_api: CrossProcessCompositorApi) -> Self {
         Self {
             player_id: None,
-            api: render_api_sender,
+            compositor_api,
             current_frame: None,
             old_frame: None,
             very_old_frame: None,
@@ -214,7 +214,7 @@ impl VideoFrameRenderer for MediaFrameRenderer {
                     updates.push(ImageUpdate::UpdateImage(
                         *image_key,
                         descriptor,
-                        ImageData::Raw(frame.get_data()),
+                        SerializableImageData::Raw(IpcSharedMemory::from_bytes(&frame.get_data())),
                     ));
                 }
 
@@ -229,7 +229,7 @@ impl VideoFrameRenderer for MediaFrameRenderer {
             Some((ref mut image_key, ref mut width, ref mut height)) => {
                 self.old_frame = Some(*image_key);
 
-                let Some(new_image_key) = self.api.generate_image_key() else {
+                let Some(new_image_key) = self.compositor_api.generate_image_key() else {
                     return;
                 };
 
@@ -245,13 +245,13 @@ impl VideoFrameRenderer for MediaFrameRenderer {
                         ImageBufferKind::Texture2D
                     };
 
-                    ImageData::External(ExternalImageData {
+                    SerializableImageData::External(ExternalImageData {
                         id: ExternalImageId(self.player_id.unwrap()),
                         channel_index: 0,
                         image_type: ExternalImageType::TextureHandle(texture_target),
                     })
                 } else {
-                    ImageData::Raw(frame.get_data())
+                    SerializableImageData::Raw(IpcSharedMemory::from_bytes(&frame.get_data()))
                 };
 
                 self.current_frame_holder
@@ -261,7 +261,7 @@ impl VideoFrameRenderer for MediaFrameRenderer {
                 updates.push(ImageUpdate::AddImage(new_image_key, descriptor, image_data));
             },
             None => {
-                let Some(image_key) = self.api.generate_image_key() else {
+                let Some(image_key) = self.compositor_api.generate_image_key() else {
                     return;
                 };
                 self.current_frame = Some((image_key, frame.get_width(), frame.get_height()));
@@ -273,13 +273,13 @@ impl VideoFrameRenderer for MediaFrameRenderer {
                         ImageBufferKind::Texture2D
                     };
 
-                    ImageData::External(ExternalImageData {
+                    SerializableImageData::External(ExternalImageData {
                         id: ExternalImageId(self.player_id.unwrap()),
                         channel_index: 0,
                         image_type: ExternalImageType::TextureHandle(texture_target),
                     })
                 } else {
-                    ImageData::Raw(frame.get_data())
+                    SerializableImageData::Raw(IpcSharedMemory::from_bytes(&frame.get_data()))
                 };
 
                 self.current_frame_holder = Some(FrameHolder::new(frame));
@@ -287,7 +287,7 @@ impl VideoFrameRenderer for MediaFrameRenderer {
                 updates.push(ImageUpdate::AddImage(image_key, descriptor, image_data));
             },
         }
-        self.api.update_images(updates);
+        self.compositor_api.update_images(updates);
     }
 }
 
@@ -446,7 +446,7 @@ impl HTMLMediaElement {
             in_flight_play_promises_queue: Default::default(),
             player: Default::default(),
             video_renderer: Arc::new(Mutex::new(MediaFrameRenderer::new(
-                document.window().get_webrender_api_sender(),
+                document.window().compositor_api().clone(),
             ))),
             audio_renderer: Default::default(),
             show_poster: Cell::new(true),