1 /*
2  *  Copyright 2015 The WebRTC Project Authors. All rights reserved.
3  *
4  *  Use of this source code is governed by a BSD-style license
5  *  that can be found in the LICENSE file in the root of the source
6  *  tree. An additional intellectual property rights grant can be found
7  *  in the file PATENTS.  All contributing project authors may
8  *  be found in the AUTHORS file in the root of the source tree.
9  */
10 
11 #ifndef RTC_BASE_BUFFER_QUEUE_H_
12 #define RTC_BASE_BUFFER_QUEUE_H_
13 
14 #include <stddef.h>
15 
16 #include <deque>
17 #include <vector>
18 
19 #include "rtc_base/buffer.h"
20 #include "rtc_base/constructor_magic.h"
21 #include "rtc_base/synchronization/mutex.h"
22 #include "rtc_base/thread_annotations.h"
23 
24 namespace rtc {
25 
26 class BufferQueue {
27  public:
28   // Creates a buffer queue with a given capacity and default buffer size.
29   BufferQueue(size_t capacity, size_t default_size);
30   virtual ~BufferQueue();
31 
32   // Return number of queued buffers.
33   size_t size() const;
34 
35   // Clear the BufferQueue by moving all Buffers from |queue_| to |free_list_|.
36   void Clear();
37 
38   // ReadFront will only read one buffer at a time and will truncate buffers
39   // that don't fit in the passed memory.
40   // Returns true unless no data could be returned.
41   bool ReadFront(void* data, size_t bytes, size_t* bytes_read);
42 
43   // WriteBack always writes either the complete memory or nothing.
44   // Returns true unless no data could be written.
45   bool WriteBack(const void* data, size_t bytes, size_t* bytes_written);
46 
47  protected:
48   // These methods are called when the state of the queue changes.
NotifyReadableForTest()49   virtual void NotifyReadableForTest() {}
NotifyWritableForTest()50   virtual void NotifyWritableForTest() {}
51 
52  private:
53   size_t capacity_;
54   size_t default_size_;
55   mutable webrtc::Mutex mutex_;
56   std::deque<Buffer*> queue_ RTC_GUARDED_BY(mutex_);
57   std::vector<Buffer*> free_list_ RTC_GUARDED_BY(mutex_);
58 
59   RTC_DISALLOW_COPY_AND_ASSIGN(BufferQueue);
60 };
61 
62 }  // namespace rtc
63 
64 #endif  // RTC_BASE_BUFFER_QUEUE_H_
65