src/cobalt/loader/image/image_cache.h

/*
 * Copyright 2015 Google Inc. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef COBALT_LOADER_IMAGE_IMAGE_CACHE_H_
#define COBALT_LOADER_IMAGE_IMAGE_CACHE_H_

#include <string>

#include "cobalt/loader/image/image_decoder.h"
#include "cobalt/loader/resource_cache.h"

namespace cobalt {
namespace loader {
namespace image {

// |ImageDecoderProvider| provides a mechanism for |ResourceCache| to create
// decoders, without requiring it to know anything about the render_tree.
struct ImageDecoderProvider {
 public:
  explicit ImageDecoderProvider(
      render_tree::ResourceProvider* resource_provider)
      : resource_provider_(resource_provider) {}

  scoped_ptr<Decoder> CreateDecoder(
      const ImageDecoder::SuccessCallback& success_callback,
      const ImageDecoder::FailureCallback& failure_callback,
      const ImageDecoder::ErrorCallback& error_callback) const {
    return make_scoped_ptr<Decoder>(
        new ImageDecoder(resource_provider_, success_callback, failure_callback,
                         error_callback));
  }

 private:
  render_tree::ResourceProvider* resource_provider_;
};

// |ImageResourceCacheType| provides the types and implements the functions
// required by |ResourceCache<ImageResourceCacheType>|
struct ImageResourceCacheType {
  typedef render_tree::Image ResourceType;
  typedef ImageDecoderProvider DecoderProviderType;

  static uint32 GetEstimatedSizeInBytes(
      const scoped_refptr<ResourceType>& resource) {
    return resource->GetEstimatedSizeInBytes();
  }
};

typedef CachedResource<ImageResourceCacheType> CachedImage;
typedef CachedResourceReferenceWithCallbacks<ImageResourceCacheType>
    CachedImageReferenceWithCallbacks;
typedef CachedImageReferenceWithCallbacks::CachedResourceReferenceVector
    CachedImageReferenceVector;

typedef ResourceCache<ImageResourceCacheType> ImageCache;

// CreateImageCache() provides a mechanism for creating an |ImageCache|, without
// requiring the caller to deal with the |ImageDecoderProvider|
inline static scoped_ptr<ImageCache> CreateImageCache(
    const std::string& name, uint32 cache_capacity,
    render_tree::ResourceProvider* resource_provider,
    loader::FetcherFactory* fetcher_factory) {
  return make_scoped_ptr<ImageCache>(new ImageCache(
      name, cache_capacity, make_scoped_ptr<ImageDecoderProvider>(
                                new ImageDecoderProvider(resource_provider)),
      fetcher_factory));
}

}  // namespace image
}  // namespace loader
}  // namespace cobalt

#endif  // COBALT_LOADER_IMAGE_IMAGE_CACHE_H_