cc/tiles/image_decode_controller.cc

   1 // Copyright 2015 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "cc/tiles/image_decode_controller.h"
   6
   7 #include "cc/debug/devtools_instrumentation.h"
   8
   9 namespace cc {
  10 namespace {
  11
  12 class ImageDecodeTaskImpl : public ImageDecodeTask {
  13  public:
  14   ImageDecodeTaskImpl(ImageDecodeController* controller,
  15                       const SkImage* image,
  16                       int layer_id,
  17                       uint64_t source_prepare_tiles_id)
  18       : controller_(controller),
  19         image_(skia::SharePtr(image)),
  20         layer_id_(layer_id),
  21         source_prepare_tiles_id_(source_prepare_tiles_id) {}
  22
  23   // Overridden from Task:
  24   void RunOnWorkerThread() override {
  25     TRACE_EVENT1("cc", "ImageDecodeTaskImpl::RunOnWorkerThread",
  26                  "source_prepare_tiles_id", source_prepare_tiles_id_);
  27     devtools_instrumentation::ScopedImageDecodeTask image_decode_task(
  28         image_.get());
  29     controller_->DecodeImage(image_.get());
  30
  31     // Release the reference after decoding image to ensure that it is not kept
  32     // alive unless needed.
  33     image_.clear();
  34   }
  35
  36   // Overridden from TileTask:
  37   void ScheduleOnOriginThread(TileTaskClient* client) override {}
  38   void CompleteOnOriginThread(TileTaskClient* client) override {
  39     controller_->OnImageDecodeTaskCompleted(layer_id_, image_.get(),
  40                                             !HasFinishedRunning());
  41   }
  42
  43  protected:
  44   ~ImageDecodeTaskImpl() override {}
  45
  46  private:
  47   ImageDecodeController* controller_;
  48   skia::RefPtr<const SkImage> image_;
  49   int layer_id_;
  50   uint64_t source_prepare_tiles_id_;
  51
  52   DISALLOW_COPY_AND_ASSIGN(ImageDecodeTaskImpl);
  53 };
  54
  55 }  // namespace
  56
  57 ImageDecodeController::ImageDecodeController() {}
  58
  59 ImageDecodeController::~ImageDecodeController() {}
  60
  61 scoped_refptr<ImageDecodeTask> ImageDecodeController::GetTaskForImage(
  62     const skia::PositionImage& image,
  63     int layer_id,
  64     uint64_t prepare_tiles_id) {
  65   uint32_t generation_id = image.image->uniqueID();
  66   scoped_refptr<ImageDecodeTask>& decode_task =
  67       image_decode_tasks_[layer_id][generation_id];
  68   if (!decode_task)
  69     decode_task = CreateTaskForImage(image.image, layer_id, prepare_tiles_id);
  70   return decode_task;
  71 }
  72
  73 scoped_refptr<ImageDecodeTask> ImageDecodeController::CreateTaskForImage(
  74     const SkImage* image,
  75     int layer_id,
  76     uint64_t prepare_tiles_id) {
  77   return make_scoped_refptr(
  78       new ImageDecodeTaskImpl(this, image, layer_id, prepare_tiles_id));
  79 }
  80
  81 void ImageDecodeController::DecodeImage(const SkImage* image) {
  82   image->preroll();
  83 }
  84
  85 void ImageDecodeController::AddLayerUsedCount(int layer_id) {
  86   ++used_layer_counts_[layer_id];
  87 }
  88
  89 void ImageDecodeController::SubtractLayerUsedCount(int layer_id) {
  90   if (--used_layer_counts_[layer_id])
  91     return;
  92
  93   // Clean up decode tasks once a layer is no longer used.
  94   used_layer_counts_.erase(layer_id);
  95   image_decode_tasks_.erase(layer_id);
  96 }
  97
  98 void ImageDecodeController::OnImageDecodeTaskCompleted(int layer_id,
  99                                                        const SkImage* image,
 100                                                        bool was_canceled) {
 101   // If the task has successfully finished, then keep the task until the layer
 102   // is no longer in use. This ensures that we only decode a image once.
 103   // TODO(vmpstr): Remove this when decode lifetime is controlled by cc.
 104   if (!was_canceled)
 105     return;
 106
 107   // Otherwise, we have to clean up the task so that a new one can be created if
 108   // we need to decode the image again.
 109   LayerImageTaskMap::iterator layer_it = image_decode_tasks_.find(layer_id);
 110   if (layer_it == image_decode_tasks_.end())
 111     return;
 112
 113   ImageTaskMap& image_tasks = layer_it->second;
 114   ImageTaskMap::iterator task_it = image_tasks.find(image->uniqueID());
 115   if (task_it == image_tasks.end())
 116     return;
 117   image_tasks.erase(task_it);
 118 }
 119
 120 }  // namespace cc