Use ByteStream in downloads system to decouple source and sink.

content/browser/download/download_buffer.cc

-// Copyright (c) 2011 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 "content/browser/download/download_buffer.h"
-
-#include "net/base/io_buffer.h"
-
-namespace content {
-
-net::IOBuffer* AssembleData(const ContentVector& contents, size_t* num_bytes) {
-  if (num_bytes)
-    *num_bytes = 0;
-
-  size_t data_len;
-  // Determine how large a buffer we need.
-  size_t assembly_buffer_length = 0;
-  for (size_t i = 0; i < contents.size(); ++i) {
-    data_len = contents[i].second;
-    assembly_buffer_length += data_len;
-  }
-
-  // 0-length IOBuffers are not allowed.
-  if (assembly_buffer_length == 0)
-    return NULL;
-
-  net::IOBuffer* assembly_buffer = new net::IOBuffer(assembly_buffer_length);
-
-  // Copy the data into |assembly_buffer|.
-  size_t bytes_copied = 0;
-  for (size_t i = 0; i < contents.size(); ++i) {
-    net::IOBuffer* data = contents[i].first;
-    data_len = contents[i].second;
-    DCHECK(data != NULL);
-    DCHECK_LE(bytes_copied + data_len, assembly_buffer_length);
-    memcpy(assembly_buffer->data() + bytes_copied, data->data(), data_len);
-    bytes_copied += data_len;
-  }
-  DCHECK_EQ(assembly_buffer_length, bytes_copied);
-
-  if (num_bytes)
-    *num_bytes = assembly_buffer_length;
-
-  return assembly_buffer;
-}
-
-DownloadBuffer::DownloadBuffer() {
-}
-
-DownloadBuffer::~DownloadBuffer() {
-}
-
-size_t DownloadBuffer::AddData(net::IOBuffer* io_buffer, size_t byte_count) {
-  base::AutoLock auto_lock(lock_);
-  contents_.push_back(std::make_pair(io_buffer, byte_count));
-  return contents_.size();
-}
-
-ContentVector* DownloadBuffer::ReleaseContents() {
-  base::AutoLock auto_lock(lock_);
-  ContentVector* other_contents = new ContentVector;
-  other_contents->swap(contents_);
-  return other_contents;
-}
-
-size_t DownloadBuffer::size() const {
-  base::AutoLock auto_lock(lock_);
-  return contents_.size();
-}
-
-}  // namespace content