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/*
* Copyright 2012 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 MEDIA_BASE_SHELL_DATA_SOURCE_READER_H_
#define MEDIA_BASE_SHELL_DATA_SOURCE_READER_H_
#include "base/bind.h"
#include "base/callback.h"
#include "base/message_loop.h"
#include "base/memory/ref_counted.h"
#include "base/memory/scoped_ptr.h"
#include "base/synchronization/lock.h"
#include "base/synchronization/waitable_event.h"
#include "media/base/data_source.h"
namespace media {
// Allows sharing of a DataSource object between multiple objects on a single
// thread, and exposes a simple BlockingRead() method to block the thread until
// data is available or error. To avoid circular smart pointer references this
// object is also the sole owner of a pointer to DataSource. If we want to add
// asynchronous reading to this object it will need its own thread and a
// callback queue.
class ShellDataSourceReader
: public base::RefCountedThreadSafe<ShellDataSourceReader> {
public:
static const int kReadError;
ShellDataSourceReader();
virtual void SetDataSource(DataSource* data_source);
// Block the calling thread's message loop until read is complete.
// returns number of bytes read or kReadError on error.
// Currently only single-threaded support.
virtual int BlockingRead(int64 position, int size, uint8* data);
// returns size of file in bytes, or -1 if file size not known. If error will
// retry getting file size on subsequent calls to FileSize().
virtual int64 FileSize();
// abort any pending read, then stop the data source
virtual void Stop(const base::Closure& callback);
protected:
friend class base::RefCountedThreadSafe<ShellDataSourceReader>;
virtual ~ShellDataSourceReader();
// blocking read callback
virtual void BlockingReadCompleted(int bytes_read);
base::Lock lock_;
DataSource* data_source_;
base::WaitableEvent blocking_read_event_;
int64 file_size_;
bool read_has_failed_;
int last_bytes_read_; // protected implicitly by blocking_read_event_
};
} // namespace media
#endif // MEDIA_BASE_SHELL_DATA_SOURCE_READER_H_