[ON HOLD] Implement pull-based design for content decoding

net/filter/brotli_stream_source.h

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "base/macros.h"
+#include "base/memory/scoped_ptr.h"
+#include "net/filter/stream_source.h"
+#include "third_party/brotli/dec/decode.h"
+
+#ifndef NET_FILTER_BROTLI_STREAM_SOURCE_H__
+#define NET_FILTER_BROTLI_STREAM_SOURCE_H__
+namespace net {
+
+class BlockBuffer;
+
+class BrotliStreamSource : public StreamSource {
+ public:
+  BrotliStreamSource(scoped_ptr<StreamSource> previous);
+  ~BrotliStreamSource() override;
+
+ private:
+  // Reported in UMA and must be kept in sync with the histograms.xml file.
+  enum class DecodingStatus : int {
+    DECODING_IN_PROGRESS = 0,
+    DECODING_DONE,
+    DECODING_ERROR,
+
+    DECODING_STATUS_COUNT
+    // DECODING_STATUS_COUNT must always be the last element in this enum.
+  };
+  // StreamSource implementation
+  net::Error ReadInternal(IOBuffer* dest_buffer,
+                          size_t buffer_size,
+                          size_t* bytes_read) override;
+  static void* AllocateMemory(void* opaque, size_t size);
+  static void FreeMemory(void* opaque, void* address);
+  void* AllocateMemoryInternal(size_t size);
+
+  void FreeMemoryInternal(void* address);
+
+  BrotliState* brotli_state_;
+
+  DecodingStatus decoding_status_;
+
+  size_t used_memory_;
+  size_t used_memory_maximum_;
+  size_t produced_bytes_;
+  size_t consumed_bytes_;
+
+  DISALLOW_COPY_AND_ASSIGN(BrotliStreamSource);
+};
+
+#endif  // NET_FILTER_BROTLI_STREAM_SOURCE_H__
+}  // namespace net