1 files changed, 88 insertions, 0 deletions
diff --git a/dom/media/mediasource/ResourceQueue.h b/dom/media/mediasource/ResourceQueue.h
new file mode 100644
index 0000000000..efd1e0c20a
--- /dev/null
+++ b/dom/media/mediasource/ResourceQueue.h
@@ -0,0 +1,88 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef MOZILLA_RESOURCEQUEUE_H_
+#define MOZILLA_RESOURCEQUEUE_H_
+
+#include "nsDeque.h"
+#include "MediaSpan.h"
+
+namespace mozilla {
+
+class ErrorResult;
+
+// A SourceBufferResource has a queue containing the data that is appended
+// to it. The queue holds instances of ResourceItem which is an array of the
+// bytes. Appending data to the SourceBufferResource pushes this onto the
+// queue.
+
+// Data is evicted once it reaches a size threshold. This pops the items off
+// the front of the queue and deletes it.  If an eviction happens then the
+// MediaSource is notified (done in SourceBuffer::AppendData) which then
+// requests all SourceBuffers to evict data up to approximately the same
+// timepoint.
+
+struct ResourceItem {
+  ResourceItem(const MediaSpan& aData, uint64_t aOffset);
+  size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const;
+  MediaSpan mData;
+  uint64_t mOffset;
+};
+
+class ResourceQueue : private nsDeque<ResourceItem> {
+ public:
+  ResourceQueue();
+
+  // Returns the logical byte offset of the start of the data.
+  uint64_t GetOffset();
+
+  // Returns the length of all items in the queue plus the offset.
+  // This is the logical length of the resource.
+  uint64_t GetLength();
+
+  // Copies aCount bytes from aOffset in the queue into aDest.
+  void CopyData(uint64_t aOffset, uint32_t aCount, char* aDest);
+
+  void AppendItem(const MediaSpan& aData);
+
+  // Tries to evict at least aSizeToEvict from the queue up until
+  // aOffset. Returns amount evicted.
+  uint32_t Evict(uint64_t aOffset, uint32_t aSizeToEvict);
+
+  uint32_t EvictBefore(uint64_t aOffset);
+
+  uint32_t EvictAll();
+
+  size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const;
+
+#if defined(DEBUG)
+  void Dump(const char* aPath);
+#endif
+
+  const uint8_t* GetContiguousAccess(int64_t aOffset, size_t aSize);
+
+ private:
+  ResourceItem* ResourceAt(uint32_t aIndex) const;
+
+  // Returns the index of the resource that contains the given
+  // logical offset. aResourceOffset will contain the offset into
+  // the resource at the given index returned if it is not null.  If
+  // no such resource exists, returns GetSize() and aOffset is
+  // untouched.
+  uint32_t GetAtOffset(uint64_t aOffset, uint32_t* aResourceOffset) const;
+
+  ResourceItem* PopFront();
+
+  // Logical length of the resource.
+  uint64_t mLogicalLength;
+
+  // Logical offset into the resource of the first element in the queue.
+  uint64_t mOffset;
+};
+
+}  // namespace mozilla
+
+#endif /* MOZILLA_RESOURCEQUEUE_H_ */