| /* |
| * 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/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); |
| |
| 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_ |