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       1             : /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
       2             : /* vim: set ts=8 sts=2 et sw=2 tw=80: */
       3             : /* This Source Code Form is subject to the terms of the Mozilla Public
       4             :  * License, v. 2.0. If a copy of the MPL was not distributed with this
       5             :  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
       6             : 
       7             : #ifndef MOZILLA_RESOURCEQUEUE_H_
       8             : #define MOZILLA_RESOURCEQUEUE_H_
       9             : 
      10             : #include "nsDeque.h"
      11             : #include "MediaData.h"
      12             : 
      13             : namespace mozilla {
      14             : 
      15             : class ErrorResult;
      16             : 
      17             : // A SourceBufferResource has a queue containing the data that is appended
      18             : // to it. The queue holds instances of ResourceItem which is an array of the
      19             : // bytes. Appending data to the SourceBufferResource pushes this onto the
      20             : // queue.
      21             : 
      22             : // Data is evicted once it reaches a size threshold. This pops the items off
      23             : // the front of the queue and deletes it.  If an eviction happens then the
      24             : // MediaSource is notified (done in SourceBuffer::AppendData) which then
      25             : // requests all SourceBuffers to evict data up to approximately the same
      26             : // timepoint.
      27             : 
      28           0 : struct ResourceItem {
      29             :   explicit ResourceItem(MediaByteBuffer* aData);
      30             :   size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const;
      31             :   RefPtr<MediaByteBuffer> mData;
      32             : };
      33             : 
      34           0 : class ResourceQueue : private nsDeque {
      35             : public:
      36             :   ResourceQueue();
      37             : 
      38             :   // Returns the logical byte offset of the start of the data.
      39             :   uint64_t GetOffset();
      40             : 
      41             :   // Returns the length of all items in the queue plus the offset.
      42             :   // This is the logical length of the resource.
      43             :   uint64_t GetLength();
      44             : 
      45             :   // Copies aCount bytes from aOffset in the queue into aDest.
      46             :   void CopyData(uint64_t aOffset, uint32_t aCount, char* aDest);
      47             : 
      48             :   void AppendItem(MediaByteBuffer* aData);
      49             : 
      50             :   // Tries to evict at least aSizeToEvict from the queue up until
      51             :   // aOffset. Returns amount evicted.
      52             :   uint32_t Evict(uint64_t aOffset, uint32_t aSizeToEvict,
      53             :                  ErrorResult& aRv);
      54             : 
      55             :   uint32_t EvictBefore(uint64_t aOffset, ErrorResult& aRv);
      56             : 
      57             :   uint32_t EvictAll();
      58             : 
      59             :   size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const;
      60             : 
      61             : #if defined(DEBUG)
      62             :   void Dump(const char* aPath);
      63             : #endif
      64             : 
      65             : private:
      66             :   ResourceItem* ResourceAt(uint32_t aIndex) const;
      67             : 
      68             :   // Returns the index of the resource that contains the given
      69             :   // logical offset. aResourceOffset will contain the offset into
      70             :   // the resource at the given index returned if it is not null.  If
      71             :   // no such resource exists, returns GetSize() and aOffset is
      72             :   // untouched.
      73             :   uint32_t GetAtOffset(uint64_t aOffset, uint32_t *aResourceOffset);
      74             : 
      75             :   ResourceItem* PopFront();
      76             : 
      77             :   // Logical length of the resource.
      78             :   uint64_t mLogicalLength;
      79             : 
      80             :   // Logical offset into the resource of the first element in the queue.
      81             :   uint64_t mOffset;
      82             : };
      83             : 
      84             : } // namespace mozilla
      85             : 
      86             : #endif /* MOZILLA_RESOURCEQUEUE_H_ */