tor-browser

The Tor Browser
git clone https://git.dasho.dev/tor-browser.git
Log | Files | Refs | README | LICENSE

ResourceQueue.h (2796B)

      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 "MediaSpan.h"
     11 #include "nsDeque.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 struct ResourceItem {
     29  ResourceItem(const MediaSpan& aData, uint64_t aOffset);
     30  size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const;
     31  MediaSpan mData;
     32  uint64_t mOffset;
     33 };
     34 
     35 class ResourceQueue : private nsDeque<ResourceItem> {
     36 public:
     37  ResourceQueue();
     38 
     39  // Returns the logical byte offset of the start of the data.
     40  uint64_t GetOffset();
     41 
     42  // Returns the length of all items in the queue plus the offset.
     43  // This is the logical length of the resource.
     44  uint64_t GetLength();
     45 
     46  // Copies aCount bytes from aOffset in the queue into aDest.
     47  void CopyData(uint64_t aOffset, uint32_t aCount, char* aDest);
     48 
     49  void AppendItem(const MediaSpan& aData);
     50 
     51  // Tries to evict at least aSizeToEvict from the queue up until
     52  // aOffset. Returns amount evicted.
     53  uint32_t Evict(uint64_t aOffset, uint32_t aSizeToEvict);
     54 
     55  uint32_t EvictBefore(uint64_t aOffset);
     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  const uint8_t* GetContiguousAccess(int64_t aOffset, size_t aSize);
     66 
     67 private:
     68  ResourceItem* ResourceAt(uint32_t aIndex) const;
     69 
     70  // Returns the index of the resource that contains the given
     71  // logical offset. aResourceOffset will contain the offset into
     72  // the resource at the given index returned if it is not null.  If
     73  // no such resource exists, returns GetSize() and aOffset is
     74  // untouched.
     75  uint32_t GetAtOffset(uint64_t aOffset, uint32_t* aResourceOffset) const;
     76 
     77  ResourceItem* PopFront();
     78 
     79  // Logical length of the resource.
     80  uint64_t mLogicalLength;
     81 
     82  // Logical offset into the resource of the first element in the queue.
     83  uint64_t mOffset;
     84 };
     85 
     86 }  // namespace mozilla
     87 
     88 #endif /* MOZILLA_RESOURCEQUEUE_H_ */