Bug 1379680. Move the displaylist ByteBuf into a Vec instead of copying. r=kats

This eliminates a copy of the displaylist on the compositor thread.

gfx/layers/wr/AsyncImagePipelineManager.cpp

@@ -353,7 +353,7 @@ AsyncImagePipelineManager::ApplyAsyncImages()
     builder.Finalize(builderContentSize, dl);
     mApi->SetDisplayList(gfx::Color(0.f, 0.f, 0.f, 0.f), epoch, LayerSize(pipeline->mScBounds.Width(), pipeline->mScBounds.Height()),
                          pipelineId, builderContentSize,
-                         dl.dl_desc, dl.dl.inner.data, dl.dl.inner.length,
+                         dl.dl_desc, dl.dl,
                          resourceUpdates);
   }
 }

gfx/layers/wr/WebRenderBridgeParent.cpp

@@ -114,6 +114,7 @@ gecko_profiler_unregister_thread()
 }
 
 namespace mozilla {
+
 namespace layers {
 
 using namespace mozilla::gfx;
@@ -598,6 +599,9 @@ WebRenderBridgeParent::RecvSetDisplayList(const gfx::IntSize& aSize,
     return IPC_FAIL(this, "Failed to deserialize resource updates");
   }
 
+
+  wr::Vec_u8 dlData(Move(dl));
+
   // If id namespaces do not match, it means the command is obsolete, probably
   // because the tab just moved to a new window.
   // In that case do not send the commands to webrender.
@@ -609,7 +613,7 @@ WebRenderBridgeParent::RecvSetDisplayList(const gfx::IntSize& aSize,
     gfx::Color clearColor(0.f, 0.f, 0.f, 0.f);
     mApi->SetDisplayList(clearColor, wr::NewEpoch(wrEpoch), LayerSize(aSize.width, aSize.height),
                         mPipelineId, aContentSize,
-                        dlDesc, dl.mData, dl.mLen,
+                        dlDesc, dlData,
                         resources);
 
     ScheduleGenerateFrame();

gfx/webrender_bindings/WebRenderAPI.cpp

@@ -265,8 +265,7 @@ WebRenderAPI::SetDisplayList(gfx::Color aBgColor,
                              wr::WrPipelineId pipeline_id,
                              const LayoutSize& content_size,
                              wr::BuiltDisplayListDescriptor dl_descriptor,
-                             uint8_t *dl_data,
-                             size_t dl_size,
+                             wr::Vec_u8& dl_data,
                              ResourceUpdateQueue& aResources)
 {
   wr_api_set_display_list(mDocHandle,
@@ -276,8 +275,7 @@ WebRenderAPI::SetDisplayList(gfx::Color aBgColor,
                           pipeline_id,
                           content_size,
                           dl_descriptor,
-                          dl_data,
-                          dl_size,
+                          &dl_data.inner,
                           aResources.Raw());
 }
 

gfx/webrender_bindings/WebRenderAPI.h

@@ -161,8 +161,7 @@ public:
                       wr::WrPipelineId pipeline_id,
                       const wr::LayoutSize& content_size,
                       wr::BuiltDisplayListDescriptor dl_descriptor,
-                      uint8_t *dl_data,
-                      size_t dl_size,
+                      wr::Vec_u8& dl_data,
                       ResourceUpdateQueue& aResources);
 
   void ClearDisplayList(Epoch aEpoch, wr::WrPipelineId pipeline_id);

gfx/webrender_bindings/WebRenderTypes.cpp

@@ -0,0 +1,24 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "WebRenderTypes.h"
+
+#include "mozilla/ipc/ByteBuf.h"
+
+namespace mozilla {
+namespace wr {
+
+Vec_u8::Vec_u8(mozilla::ipc::ByteBuf&& aSrc) {
+  inner.data = aSrc.mData;
+  inner.length = aSrc.mLen;
+  inner.capacity = aSrc.mCapacity;
+  aSrc.mData = nullptr;
+  aSrc.mLen = 0;
+  aSrc.mCapacity = 0;
+}
+
+} // namespace wr
+} // namespace mozilla

gfx/webrender_bindings/WebRenderTypes.h

@@ -21,6 +21,11 @@
 #include "nsStyleConsts.h"
 
 namespace mozilla {
+
+namespace ipc {
+class ByteBuf;
+} // namespace ipc
+
 namespace wr {
 
 typedef wr::WrWindowId WindowId;
@@ -576,6 +581,8 @@ struct Vec_u8 {
     src.SetEmpty();
   }
 
+  explicit Vec_u8(mozilla::ipc::ByteBuf&& aSrc);
+
   Vec_u8&
   operator=(Vec_u8&& src) {
     inner = src.inner;

gfx/webrender_bindings/moz.build

@@ -29,6 +29,7 @@ UNIFIED_SOURCES += [
     'RenderTextureHostOGL.cpp',
     'RenderThread.cpp',
     'WebRenderAPI.cpp',
+    'WebRenderTypes.cpp',
 ]
 
 if CONFIG['MOZ_WIDGET_TOOLKIT'] == 'cocoa':

gfx/webrender_bindings/src/bindings.rs

@@ -958,8 +958,7 @@ pub unsafe extern "C" fn wr_api_set_display_list(
     pipeline_id: WrPipelineId,
     content_size: LayoutSize,
     dl_descriptor: BuiltDisplayListDescriptor,
-    dl_data: *mut u8,
-    dl_size: usize,
+    dl_data: &mut WrVecU8,
     resources: &mut ResourceUpdates,
 ) {
     let resource_updates = mem::replace(resources, ResourceUpdates::new());
@@ -971,10 +970,7 @@ pub unsafe extern "C" fn wr_api_set_display_list(
     // but I suppose it is a good default.
     let preserve_frame_state = true;
 
-    let dl_slice = make_slice(dl_data, dl_size);
-    let mut dl_vec = Vec::new();
-    // XXX: see if we can get rid of the copy here
-    dl_vec.extend_from_slice(dl_slice);
+    let dl_vec = dl_data.flush_into_vec();
     let dl = BuiltDisplayList::from_data(dl_vec, dl_descriptor);
 
     dh.api.set_display_list(

gfx/webrender_bindings/webrender_ffi_generated.h

@@ -1068,8 +1068,7 @@ void wr_api_set_display_list(DocumentHandle *aDh,
                              WrPipelineId aPipelineId,
                              LayoutSize aContentSize,
                              BuiltDisplayListDescriptor aDlDescriptor,
-                             uint8_t *aDlData,
-                             size_t aDlSize,
+                             WrVecU8 *aDlData,
                              ResourceUpdates *aResources)
 WR_FUNC;