1 files changed, 76 insertions, 0 deletions
diff --git a/dom/media/BufferMediaResource.h b/dom/media/BufferMediaResource.h
new file mode 100644
index 0000000000..693704a2ae
--- /dev/null
+++ b/dom/media/BufferMediaResource.h
@@ -0,0 +1,76 @@
+/* vim:set ts=2 sw=2 sts=2 et cindent: */
+/* 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/. */
+
+#if !defined(BufferMediaResource_h_)
+#  define BufferMediaResource_h_
+
+#  include "MediaResource.h"
+#  include "nsISeekableStream.h"
+#  include <algorithm>
+
+namespace mozilla {
+
+DDLoggedTypeDeclNameAndBase(BufferMediaResource, MediaResource);
+
+// A simple MediaResource based on an in memory buffer.  This class accepts
+// the address and the length of the buffer, and simulates a read/seek API
+// on top of it.  The Read implementation involves copying memory, which is
+// unfortunate, but the MediaResource interface mandates that.
+class BufferMediaResource
+    : public MediaResource,
+      public DecoderDoctorLifeLogger<BufferMediaResource> {
+ public:
+  BufferMediaResource(const uint8_t* aBuffer, uint32_t aLength)
+      : mBuffer(aBuffer), mLength(aLength) {}
+
+ protected:
+  virtual ~BufferMediaResource() = default;
+
+ private:
+  // These methods are called off the main thread.
+  nsresult ReadAt(int64_t aOffset, char* aBuffer, uint32_t aCount,
+                  uint32_t* aBytes) override {
+    if (aOffset < 0 || aOffset > mLength) {
+      return NS_ERROR_FAILURE;
+    }
+    *aBytes = std::min(mLength - static_cast<uint32_t>(aOffset), aCount);
+    memcpy(aBuffer, mBuffer + aOffset, *aBytes);
+    return NS_OK;
+  }
+  // Memory-based and no locks, caching discouraged.
+  bool ShouldCacheReads() override { return false; }
+
+  void Pin() override {}
+  void Unpin() override {}
+  int64_t GetLength() override { return mLength; }
+  int64_t GetNextCachedData(int64_t aOffset) override { return aOffset; }
+  int64_t GetCachedDataEnd(int64_t aOffset) override {
+    return std::max(aOffset, int64_t(mLength));
+  }
+  bool IsDataCachedToEndOfResource(int64_t aOffset) override { return true; }
+  nsresult ReadFromCache(char* aBuffer, int64_t aOffset,
+                         uint32_t aCount) override {
+    if (aOffset < 0) {
+      return NS_ERROR_FAILURE;
+    }
+
+    uint32_t bytes = std::min(mLength - static_cast<uint32_t>(aOffset), aCount);
+    memcpy(aBuffer, mBuffer + aOffset, bytes);
+    return NS_OK;
+  }
+
+  nsresult GetCachedRanges(MediaByteRangeSet& aRanges) override {
+    aRanges += MediaByteRange(0, int64_t(mLength));
+    return NS_OK;
+  }
+
+ private:
+  const uint8_t* mBuffer;
+  uint32_t mLength;
+};
+
+}  // namespace mozilla
+
+#endif