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// 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_DECODER_H_
#define COBALT_LOADER_IMAGE_IMAGE_DECODER_H_
#include <string>
#include "base/atomicops.h"
#include "base/callback.h"
#include "cobalt/loader/decoder.h"
#include "cobalt/loader/image/image.h"
#include "cobalt/loader/image/image_data_decoder.h"
#include "cobalt/render_tree/resource_provider.h"
namespace cobalt {
namespace loader {
namespace image {
// This class handles decoding any image. If image type is not given, it is
// determined by the signature in the data. Then an image data decoder specific
// to that image type is created to parse the data. When the decoding is
// complete, the image decoder retrieves the data and uses it to create the
// image.
class ImageDecoder : public Decoder {
public:
// The various types of images we support decoding.
enum ImageType {
kImageTypeInvalid,
kImageTypeGIF,
kImageTypeJPEG,
kImageTypePNG,
kImageTypeWebP,
};
typedef base::Callback<void(const scoped_refptr<Image>&)> SuccessCallback;
typedef base::Callback<void(const std::string&)> ErrorCallback;
ImageDecoder(render_tree::ResourceProvider* resource_provider,
const SuccessCallback& success_callback,
const ErrorCallback& error_callback);
ImageDecoder(render_tree::ResourceProvider* resource_provider,
const SuccessCallback& success_callback,
const ErrorCallback& error_callback, ImageType image_type);
// From Decoder.
LoadResponseType OnResponseStarted(
Fetcher* fetcher,
const scoped_refptr<net::HttpResponseHeaders>& headers) override;
void DecodeChunk(const char* data, size_t size) override;
void Finish() override;
bool Suspend() override;
void Resume(render_tree::ResourceProvider* resource_provider) override;
// Called when this ImageDecoder's deletion has been posted to a message loop.
// This prevents any additional decoding from occuring prior to the decoder
// being deleted.
void SetDeletionPending();
// Call this function to use the StubImageDecoder which produces a small image
// without decoding.
static void UseStubImageDecoder();
private:
enum State {
kWaitingForHeader,
kDecoding,
kNotApplicable,
kUnsupportedImageFormat,
kSuspended,
};
// The current longest signature is WEBP signature.
static const size_t kLengthOfLongestSignature = 14;
struct SignatureCache {
uint8 data[kLengthOfLongestSignature];
size_t position;
};
void DecodeChunkInternal(const uint8* input_bytes, size_t size);
bool InitializeInternalDecoder(const uint8* input_bytes, size_t size,
size_t* consumed_size);
render_tree::ResourceProvider* resource_provider_;
const SuccessCallback success_callback_;
const ErrorCallback error_callback_;
ImageType image_type_;
scoped_ptr<ImageDataDecoder> decoder_;
SignatureCache signature_cache_;
State state_;
std::string error_message_;
std::string mime_type_;
// Whether or not there is a pending task deleting this decoder on a message
// loop.
base::subtle::Atomic32 is_deletion_pending_;
};
} // namespace image
} // namespace loader
} // namespace cobalt
#endif // COBALT_LOADER_IMAGE_IMAGE_DECODER_H_