| // Copyright (c) 2012 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #ifndef MEDIA_BASE_SERIAL_RUNNER_H_ |
| #define MEDIA_BASE_SERIAL_RUNNER_H_ |
| |
| #include <memory> |
| |
| #include "base/callback.h" |
| #include "base/containers/queue.h" |
| #include "base/macros.h" |
| #include "base/memory/ref_counted.h" |
| #include "base/memory/weak_ptr.h" |
| #include "media/base/media_export.h" |
| #include "media/base/pipeline_status.h" |
| |
| namespace base { |
| class SingleThreadTaskRunner; |
| } |
| |
| namespace media { |
| |
| // Runs a series of bound functions accepting Closures or PipelineStatusCB. |
| // SerialRunner doesn't use regular Closure/PipelineStatusCBs as it late binds |
| // the completion callback as the series progresses. |
| class MEDIA_EXPORT SerialRunner { |
| public: |
| // TODO(dalecurtis): Change SerialRunner to use OnceCallback. |
| typedef base::Callback<void(const base::Closure&)> BoundClosure; |
| typedef base::Callback<void(const PipelineStatusCB&)> BoundPipelineStatusCB; |
| |
| // Serial queue of bound functions to run. |
| class MEDIA_EXPORT Queue { |
| public: |
| Queue(); |
| Queue(const Queue& other); |
| ~Queue(); |
| |
| void Push(const base::Closure& closure); |
| void Push(const BoundClosure& bound_fn); |
| void Push(const BoundPipelineStatusCB& bound_fn); |
| |
| private: |
| friend class SerialRunner; |
| |
| BoundPipelineStatusCB Pop(); |
| bool empty(); |
| |
| base::queue<BoundPipelineStatusCB> bound_fns_; |
| }; |
| |
| // Executes the bound functions in series, executing |done_cb| when finished. |
| // |
| // All bound functions are executed on the thread that Run() is called on, |
| // including |done_cb|. |
| // |
| // To eliminate an unnecessary posted task, the first function is executed |
| // immediately on the caller's stack. It is *strongly advised* to ensure |
| // the calling code does no more work after the call to Run(). |
| // |
| // In all cases, |done_cb| is guaranteed to execute on a separate calling |
| // stack. |
| // |
| // Deleting the object will prevent execution of any unstarted bound |
| // functions, including |done_cb|. |
| static std::unique_ptr<SerialRunner> Run(const Queue& bound_fns, |
| const PipelineStatusCB& done_cb); |
| |
| private: |
| friend std::default_delete<SerialRunner>; |
| |
| SerialRunner(const Queue& bound_fns, const PipelineStatusCB& done_cb); |
| ~SerialRunner(); |
| |
| void RunNextInSeries(PipelineStatus last_status); |
| |
| scoped_refptr<base::SingleThreadTaskRunner> task_runner_; |
| Queue bound_fns_; |
| PipelineStatusCB done_cb_; |
| |
| // NOTE: Weak pointers must be invalidated before all other member variables. |
| base::WeakPtrFactory<SerialRunner> weak_factory_; |
| |
| DISALLOW_COPY_AND_ASSIGN(SerialRunner); |
| }; |
| |
| } // namespace media |
| |
| #endif // MEDIA_BASE_SERIAL_RUNNER_H_ |