src/content/browser/screen_orientation/screen_orientation_message_filter_android.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 "content/browser/screen_orientation/screen_orientation_message_filter_android.h"
   6
   7 #include "content/browser/screen_orientation/screen_orientation_delegate_android.h"
   8 #include "content/common/screen_orientation_messages.h"
   9
  10 namespace content {
  11
  12 ScreenOrientationMessageFilterAndroid::ScreenOrientationMessageFilterAndroid()
  13     : BrowserMessageFilter(ScreenOrientationMsgStart)
  14     , listeners_count_(0) {
  15 }
  16
  17 ScreenOrientationMessageFilterAndroid::~ScreenOrientationMessageFilterAndroid()
  18 {
  19   if (listeners_count_ > 0)
  20     ScreenOrientationDelegateAndroid::StopAccurateListening();
  21 }
  22
  23 bool ScreenOrientationMessageFilterAndroid::OnMessageReceived(
  24     const IPC::Message& message) {
  25   bool handled = true;
  26   IPC_BEGIN_MESSAGE_MAP(ScreenOrientationMessageFilterAndroid, message)
  27     IPC_MESSAGE_HANDLER(ScreenOrientationHostMsg_StartListening,
  28                         OnStartListening)
  29     IPC_MESSAGE_HANDLER(ScreenOrientationHostMsg_StopListening,
  30                         OnStopListening)
  31     IPC_MESSAGE_UNHANDLED(handled = false)
  32   IPC_END_MESSAGE_MAP()
  33   return handled;
  34 }
  35
  36 void ScreenOrientationMessageFilterAndroid::OnStartListening() {
  37   ++listeners_count_;
  38   if (listeners_count_ == 1)
  39     ScreenOrientationDelegateAndroid::StartAccurateListening();
  40 }
  41
  42 void ScreenOrientationMessageFilterAndroid::OnStopListening() {
  43   DCHECK(listeners_count_ > 0);
  44   --listeners_count_;
  45   if (listeners_count_ == 0)
  46     ScreenOrientationDelegateAndroid::StopAccurateListening();
  47 }
  48
  49 }  // namespace content