Implement the logic to kick off image decoding jobs for TileManager

cc/tile_manager.cc

Index: cc/tile_manager.cc
diff --git a/cc/tile_manager.cc b/cc/tile_manager.cc
index 932c2a836d4181fd8c6f099fceaf76c5e223bbf4..424d3ad0f151f55f820d645db91e10ceab15eea3 100644
--- a/cc/tile_manager.cc
+++ b/cc/tile_manager.cc
@@ -66,6 +66,16 @@ class RasterThread : public base::Thread {
         base::Bind(&RasterThread::RunReply, base::Unretained(this), reply));
   }
 
+  void PostImageDecodingTaskAndReply(const tracked_objects::Location& from_here,
+                                     skia::LazyPixelRef* pixel_ref,
+                                     const base::Closure& reply) {
+    ++num_pending_tasks_;
+    message_loop_proxy()->PostTaskAndReply(
+        from_here,
+        base::Bind(&skia::LazyPixelRef::Decode, base::Unretained(pixel_ref)),
+        base::Bind(&RasterThread::RunReply, base::Unretained(this), reply));
+  }
+
  private:
   static void RunRasterTask(PicturePileImpl* picture_pile,
                             uint8_t* mapped_buffer,
@@ -246,6 +256,10 @@ void TileManager::ManageTiles() {
     }
 
     mts.bin = EVENTUALLY_BIN;
+
+    // Update all the SkPixelRefs this tile intersects.
+    mts.pending_pixel_refs.clear();
+    mts.has_image_decoding_info = false;

[reveman, 2012/12/11 01:35:42]

Why do you clear this here? Shouldn't we just initialize has_image_decoding_info
when the managed tile is constructed and be done.

[qinmin, 2012/12/11 04:30:15]

moved it to the ctor
On 2012/12/11 01:35:42, David Reveman wrote:

   }
 
   // Memory limit policy works by mapping some bin states to the NEVER bin.
@@ -284,7 +298,7 @@ void TileManager::ManageTiles() {
   AssignGpuMemoryToTiles();
 
   // Finally, kick the rasterizer.
-  DispatchMoreRasterTasks();
+  DispatchMoreTasks();
 }
 
 void TileManager::CheckForCompletedSetPixels() {
@@ -363,6 +377,15 @@ void TileManager::AssignGpuMemoryToTiles() {
       tiles_that_need_to_be_rasterized_.end());
 }
 
+void TileManager::GetImageInformationForTile(Tile* tile) {

[reveman, 2012/12/11 01:35:42]

I don't think having this in a separate function is worth much now that you only
call it from one place. Just move this to HasImageDecodingTasks.

[qinmin, 2012/12/11 04:30:15]

Done.

+  ManagedTileState& managed_state = tile->managed_state();
+  if (!managed_state.has_image_decoding_info) {
+    const_cast<PicturePileImpl *>(tile->picture_pile())->GatherPixelRefs(
+        tile->content_rect_, managed_state.pending_pixel_refs);
+    managed_state.has_image_decoding_info = true;
+  }
+}
+
 void TileManager::FreeResourcesForTile(Tile* tile) {
   ManagedTileState& managed_tile_state = tile->managed_state();
   DCHECK(managed_tile_state.can_be_freed);
@@ -370,28 +393,113 @@ void TileManager::FreeResourcesForTile(Tile* tile) {
     resource_pool_->ReleaseResource(managed_tile_state.resource.Pass());
 }
 
-void TileManager::DispatchMoreRasterTasks() {
-  while (!tiles_that_need_to_be_rasterized_.empty()) {
-    RasterThread* thread = 0;
-
-    for (RasterThreadVector::iterator it = raster_threads_.begin();
-         it != raster_threads_.end(); ++it) {
-      if ((*it)->num_pending_tasks() == kNumPendingRasterTasksPerThread)
-        continue;
-      // Check if this is the best thread we've found so far.
-      if (!thread || (*it)->num_pending_tasks() < thread->num_pending_tasks())
-        thread = *it;
+RasterThread* TileManager::GetFreeRasterThread() {
+  RasterThread* thread = 0;
+  for (RasterThreadVector::iterator it = raster_threads_.begin();
+       it != raster_threads_.end(); ++it) {
+    if ((*it)->num_pending_tasks() == kNumPendingRasterTasksPerThread)
+      continue;
+    // Check if this is the best thread we've found so far.
+    if (!thread || (*it)->num_pending_tasks() < thread->num_pending_tasks())
+      thread = *it;
+  }
+  return thread;
+}
+
+void TileManager::DispatchMoreTasks() {
+  // Because tiles in the image decoding list have higher priorities, we
+  // need to process those tiles first before we start to handle the tiles
+  // in the need_to_be_rasterized queue.
+  for (TileList::iterator it = tiles_have_image_decoding_tasks_.begin();
+      it != tiles_have_image_decoding_tasks_.end(); ++it) {
+    if (!HasImageDecodingTasks(*it)) {
+      RasterThread* thread = GetFreeRasterThread();
+      if (!thread)
+        return;
+      DispatchOneRasterTask(thread, *it);
+      tiles_have_image_decoding_tasks_.erase(it);

[reveman, 2012/12/11 01:35:42]

do you need a temporary "to be removed" list here?

[qinmin, 2012/12/11 04:30:15]

Changed the code to erase(it++).

On 2012/12/11 01:35:42, David Reveman wrote:

     }
+  }
 
-    // Stop dispatching tasks when all threads are busy.
+  // Process all tiles in the need_to_be_rasterized queue. If a tile has
+  // image decoding tasks, put it to the back of the image decoding list.
+  while (!tiles_that_need_to_be_rasterized_.empty()) {
+    RasterThread* thread = GetFreeRasterThread();
     if (!thread)
         return;
 
-    DispatchOneRasterTask(thread, tiles_that_need_to_be_rasterized_.back());
+    Tile* tile = tiles_that_need_to_be_rasterized_.back();
+    if (HasImageDecodingTasks(tile))
+      tiles_have_image_decoding_tasks_.push_back(tile);
+    else
+      DispatchOneRasterTask(thread, tile);

[reveman, 2012/12/11 01:35:42]

hm, thread might not be the correct thread to dispatch this to after
HasImageDecodingTasks has been called. You should probably change this so it's
similar to the above loop.

[qinmin, 2012/12/11 04:30:15]

You are right, somehow i missed that when rewriting this
On 2012/12/11 01:35:42, David Reveman wrote:

     tiles_that_need_to_be_rasterized_.pop_back();
   }
 }
 
+bool TileManager::HasImageDecodingTasks(Tile* tile) {

[reveman, 2012/12/11 01:35:42]

Can you change this to something like:
void DispatchImageDecodingTasksForTile(Tile* tile)
so it's clear that this function will dispatch tasks. We don't need the return
value anymore, right? Can just check pending_pixel_refs.empty() directly in
DispatchMoreTasks.

[qinmin, 2012/12/11 04:30:15]

Done.

On 2012/12/11 01:35:42, David Reveman wrote:

+  if (!tile->managed_state().has_image_decoding_info)
+    GetImageInformationForTile(tile);
+
+  RasterThread* thread = 0;
+  std::list<skia::LazyPixelRef*>& pending_pixel_refs =
+      tile->managed_state().pending_pixel_refs;
+  for (std::list<skia::LazyPixelRef*>::iterator it = pending_pixel_refs.begin();
+      it != pending_pixel_refs.end(); ++it) {
+    if (pending_decode_tasks_.end() != pending_decode_tasks_.find(
+        (*it)->getGenerationID()))
+      continue;
+    if ((*it)->PrepareToDecode(skia::LazyPixelRef::PrepareParams())) {
+      pending_pixel_refs.erase(it);
+    } else {
+      thread = GetFreeRasterThread();
+      if (thread)
+        DispatchOneImageDecodingTask(thread, tile, *it);
+    }
+  }
+
+  return !pending_pixel_refs.empty();
+}
+
+void TileManager::DispatchOneImageDecodingTask(RasterThread* thread,
+                                               scoped_refptr<Tile> tile,
+                                               skia::LazyPixelRef* pixel_ref) {
+  TRACE_EVENT0("cc", "TileManager::DispatchOneImageDecodingTask");
+  uint32_t pixel_ref_id = pixel_ref->getGenerationID();
+  DCHECK(pending_decode_tasks_.end() ==
+      pending_decode_tasks_.find(pixel_ref_id));
+  pending_decode_tasks_[pixel_ref_id] = pixel_ref;
+
+  thread->PostImageDecodingTaskAndReply(
+          FROM_HERE,
+          pixel_ref,
+          base::Bind(&TileManager::OnImageDecodingTaskCompleted,
+                     base::Unretained(this),
+                     tile,
+                     pixel_ref_id));
+}
+
+void TileManager::OnImageDecodingTaskCompleted(scoped_refptr<Tile> tile,
+                                               uint32_t pixel_ref_id) {
+  TRACE_EVENT0("cc", "TileManager::OnImageDecoded");
+  pending_decode_tasks_.erase(pixel_ref_id);
+
+  for (TileList::iterator it = tiles_have_image_decoding_tasks_.begin();
+      it != tiles_have_image_decoding_tasks_.end(); ++it) {
+    std::list<skia::LazyPixelRef*>& pixel_refs =
+        (*it)->managed_state().pending_pixel_refs;
+    for (std::list<skia::LazyPixelRef*>::iterator pixel_it =
+        pixel_refs.begin(); pixel_it != pixel_refs.end(); ++pixel_it) {
+      if (pixel_ref_id == (*pixel_it)->getGenerationID()) {
+        pixel_refs.erase(pixel_it);
+        break;
+      }
+    }
+  }
+
+  DispatchMoreTasks();
+}
+
 void TileManager::DispatchOneRasterTask(
     RasterThread* thread, scoped_refptr<Tile> tile) {
   TRACE_EVENT0("cc", "TileManager::DispatchOneRasterTask");
@@ -446,7 +554,7 @@ void TileManager::OnRasterTaskCompleted(
   // tiles. The result of this could be that this tile is no longer
   // allowed to use gpu memory and in that case we need to abort
   // initialization and free all associated resources before calling
-  // DispatchMoreRasterTasks().
+  // DispatchMoreTasks().
   AssignGpuMemoryToTiles();
 
   // Finish resource initialization if |can_use_gpu_memory| is true.
@@ -471,7 +579,7 @@ void TileManager::OnRasterTaskCompleted(
     managed_tile_state.resource_is_being_initialized = false;
   }
 
-  DispatchMoreRasterTasks();
+  DispatchMoreTasks();
 }
 
 void TileManager::DidFinishTileInitialization(Tile* tile) {