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                       SkPixelRef* pixel_ref,
  16                       int layer_id,
  17                       uint64_t source_prepare_tiles_id)
  18       : controller_(controller),
  19         pixel_ref_(skia::SharePtr(pixel_ref)),
  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         pixel_ref_.get());
  29     controller_->DecodePixelRef(pixel_ref_.get());
  30
  31     // Release the reference after decoding image to ensure that it is not kept
  32     // alive unless needed.
  33     pixel_ref_.clear();
  34   }
  35
  36   // Overridden from TileTask:
  37   void ScheduleOnOriginThread(TileTaskClient* client) override {}
  38   void CompleteOnOriginThread(TileTaskClient* client) override {
  39     controller_->OnImageDecodeTaskCompleted(layer_id_, pixel_ref_.get(),
  40                                             !HasFinishedRunning());
  41   }
  42
  43  protected:
  44   ~ImageDecodeTaskImpl() override {}
  45
  46  private:
  47   ImageDecodeController* controller_;
  48   skia::RefPtr<SkPixelRef> pixel_ref_;
  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::GetTaskForPixelRef(
  62     const skia::PositionPixelRef& pixel_ref,
  63     int layer_id,
  64     uint64_t prepare_tiles_id) {
  65   uint32_t generation_id = pixel_ref.pixel_ref->getGenerationID();
  66   scoped_refptr<ImageDecodeTask>& decode_task =
  67       image_decode_tasks_[layer_id][generation_id];
  68   if (!decode_task)
  69     decode_task =
  70         CreateTaskForPixelRef(pixel_ref.pixel_ref, layer_id, prepare_tiles_id);
  71   return decode_task;
  72 }
  73
  74 scoped_refptr<ImageDecodeTask> ImageDecodeController::CreateTaskForPixelRef(
  75     SkPixelRef* pixel_ref,
  76     int layer_id,
  77     uint64_t prepare_tiles_id) {
  78   return make_scoped_refptr(
  79       new ImageDecodeTaskImpl(this, pixel_ref, layer_id, prepare_tiles_id));
  80 }
  81
  82 void ImageDecodeController::DecodePixelRef(SkPixelRef* pixel_ref) {
  83   // This will cause the image referred to by pixel ref to be decoded.
  84   pixel_ref->lockPixels();
  85   pixel_ref->unlockPixels();
  86 }
  87
  88 void ImageDecodeController::AddLayerUsedCount(int layer_id) {
  89   ++used_layer_counts_[layer_id];
  90 }
  91
  92 void ImageDecodeController::SubtractLayerUsedCount(int layer_id) {
  93   if (--used_layer_counts_[layer_id])
  94     return;
  95
  96   // Clean up decode tasks once a layer is no longer used.
  97   used_layer_counts_.erase(layer_id);
  98   image_decode_tasks_.erase(layer_id);
  99 }
 100
 101 void ImageDecodeController::OnImageDecodeTaskCompleted(int layer_id,
 102                                                        SkPixelRef* pixel_ref,
 103                                                        bool was_canceled) {
 104   // If the task has successfully finished, then keep the task until the layer
 105   // is no longer in use. This ensures that we only decode a pixel ref once.
 106   // TODO(vmpstr): Remove this when decode lifetime is controlled by cc.
 107   if (!was_canceled)
 108     return;
 109
 110   // Otherwise, we have to clean up the task so that a new one can be created if
 111   // we need to decode the pixel ref again.
 112   LayerPixelRefTaskMap::iterator layer_it = image_decode_tasks_.find(layer_id);
 113   if (layer_it == image_decode_tasks_.end())
 114     return;
 115
 116   PixelRefTaskMap& pixel_ref_tasks = layer_it->second;
 117   PixelRefTaskMap::iterator task_it =
 118       pixel_ref_tasks.find(pixel_ref->getGenerationID());
 119   if (task_it == pixel_ref_tasks.end())
 120     return;
 121   pixel_ref_tasks.erase(task_it);
 122 }
 123
 124 }  // namespace cc