chrome/utility/media_galleries/ipc_data_source.cc

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "chrome/utility/media_galleries/ipc_data_source.h"
   6
   7 #include "base/message_loop/message_loop_proxy.h"
   8 #include "chrome/common/extensions/chrome_utility_extensions_messages.h"
   9 #include "content/public/utility/utility_thread.h"
  10
  11 namespace metadata {
  12
  13 IPCDataSource::IPCDataSource(int64 total_size)
  14     : total_size_(total_size),
  15       utility_task_runner_(base::MessageLoopProxy::current()),
  16       next_request_id_(0) {
  17   data_source_thread_checker_.DetachFromThread();
  18 }
  19
  20 IPCDataSource::~IPCDataSource() {
  21   DCHECK(utility_thread_checker_.CalledOnValidThread());
  22 }
  23
  24 void IPCDataSource::Stop() {
  25   DCHECK(data_source_thread_checker_.CalledOnValidThread());
  26 }
  27
  28 void IPCDataSource::Read(int64 position, int size, uint8* data,
  29                          const DataSource::ReadCB& read_cb) {
  30   DCHECK(data_source_thread_checker_.CalledOnValidThread());
  31   utility_task_runner_->PostTask(
  32       FROM_HERE,
  33       base::Bind(&IPCDataSource::ReadOnUtilityThread, base::Unretained(this),
  34                  position, size, data, read_cb));
  35 }
  36
  37 bool IPCDataSource::GetSize(int64* size_out) {
  38   DCHECK(data_source_thread_checker_.CalledOnValidThread());
  39   *size_out = total_size_;
  40   return true;
  41 }
  42
  43 bool IPCDataSource::IsStreaming() {
  44   DCHECK(data_source_thread_checker_.CalledOnValidThread());
  45   return false;
  46 }
  47
  48 void IPCDataSource::SetBitrate(int bitrate) {
  49   DCHECK(data_source_thread_checker_.CalledOnValidThread());
  50 }
  51
  52 bool IPCDataSource::OnMessageReceived(const IPC::Message& message) {
  53   DCHECK(utility_thread_checker_.CalledOnValidThread());
  54   bool handled = true;
  55   IPC_BEGIN_MESSAGE_MAP(IPCDataSource, message)
  56     IPC_MESSAGE_HANDLER(ChromeUtilityMsg_RequestBlobBytes_Finished,
  57                         OnRequestBlobBytesFinished)
  58     IPC_MESSAGE_UNHANDLED(handled = false)
  59   IPC_END_MESSAGE_MAP()
  60   return handled;
  61 }
  62
  63 IPCDataSource::Request::Request()
  64     : destination(NULL) {
  65 }
  66
  67 IPCDataSource::Request::~Request() {
  68 }
  69
  70 void IPCDataSource::ReadOnUtilityThread(int64 position, int size, uint8* data,
  71                                         const DataSource::ReadCB& read_cb) {
  72   DCHECK(utility_thread_checker_.CalledOnValidThread());
  73   CHECK_GE(total_size_, 0);
  74   CHECK_GE(position, 0);
  75   CHECK_GE(size, 0);
  76
  77   // Cap position and size within bounds.
  78   position = std::min(position, total_size_);
  79   int64 clamped_size =
  80       std::min(static_cast<int64>(size), total_size_ - position);
  81
  82   int64 request_id = ++next_request_id_;
  83
  84   Request request;
  85   request.destination = data;
  86   request.callback = read_cb;
  87
  88   pending_requests_[request_id] = request;
  89   content::UtilityThread::Get()->Send(new ChromeUtilityHostMsg_RequestBlobBytes(
  90       request_id, position, clamped_size));
  91 }
  92
  93 void IPCDataSource::OnRequestBlobBytesFinished(int64 request_id,
  94                                                const std::string& bytes) {
  95   DCHECK(utility_thread_checker_.CalledOnValidThread());
  96   std::map<int64, Request>::iterator it = pending_requests_.find(request_id);
  97
  98   if (it == pending_requests_.end())
  99     return;
 100
 101   std::copy(bytes.begin(), bytes.end(), it->second.destination);
 102   it->second.callback.Run(bytes.size());
 103
 104   pending_requests_.erase(it);
 105 }
 106
 107 }  // namespace metadata