content/browser/device_monitor_udev.cc

   1 // Copyright 2013 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 // libudev is used for monitoring device changes.
   6
   7 #include "content/browser/device_monitor_udev.h"
   8
   9 #include <string>
  10
  11 #include "base/system_monitor/system_monitor.h"
  12 #include "content/browser/udev_linux.h"
  13 #include "content/public/browser/browser_thread.h"
  14 #include "device/udev_linux/udev.h"
  15
  16 namespace {
  17
  18 struct SubsystemMap {
  19   base::SystemMonitor::DeviceType device_type;
  20   const char* subsystem;
  21   const char* devtype;
  22 };
  23
  24 const char kAudioSubsystem[] = "sound";
  25 const char kVideoSubsystem[] = "video4linux";
  26
  27 // Add more subsystems here for monitoring.
  28 const SubsystemMap kSubsystemMap[] = {
  29   { base::SystemMonitor::DEVTYPE_AUDIO_CAPTURE, kAudioSubsystem, NULL },
  30   { base::SystemMonitor::DEVTYPE_VIDEO_CAPTURE, kVideoSubsystem, NULL },
  31 };
  32
  33 }  // namespace
  34
  35 namespace content {
  36
  37 DeviceMonitorLinux::DeviceMonitorLinux() {
  38   DCHECK(BrowserThread::IsMessageLoopValid(BrowserThread::IO));
  39   BrowserThread::PostTask(BrowserThread::IO,
  40       FROM_HERE,
  41       base::Bind(&DeviceMonitorLinux::Initialize, base::Unretained(this)));
  42 }
  43
  44 DeviceMonitorLinux::~DeviceMonitorLinux() {
  45 }
  46
  47 void DeviceMonitorLinux::Initialize() {
  48   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
  49
  50   // We want to be notified of IO message loop destruction to delete |udev_|.
  51   base::MessageLoop::current()->AddDestructionObserver(this);
  52
  53   std::vector<UdevLinux::UdevMonitorFilter> filters;
  54   for (size_t i = 0; i < arraysize(kSubsystemMap); ++i) {
  55     filters.push_back(UdevLinux::UdevMonitorFilter(
  56         kSubsystemMap[i].subsystem, kSubsystemMap[i].devtype));
  57   }
  58   udev_.reset(new UdevLinux(filters,
  59       base::Bind(&DeviceMonitorLinux::OnDevicesChanged,
  60                  base::Unretained(this))));
  61 }
  62
  63 void DeviceMonitorLinux::WillDestroyCurrentMessageLoop() {
  64   // Called on IO thread.
  65   udev_.reset();
  66 }
  67
  68 void DeviceMonitorLinux::OnDevicesChanged(udev_device* device) {
  69   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
  70   DCHECK(device);
  71
  72   base::SystemMonitor::DeviceType device_type =
  73       base::SystemMonitor::DEVTYPE_UNKNOWN;
  74   std::string subsystem(device::udev_device_get_subsystem(device));
  75   for (size_t i = 0; i < arraysize(kSubsystemMap); ++i) {
  76     if (subsystem == kSubsystemMap[i].subsystem) {
  77       device_type = kSubsystemMap[i].device_type;
  78       break;
  79     }
  80   }
  81   DCHECK_NE(device_type, base::SystemMonitor::DEVTYPE_UNKNOWN);
  82
  83   base::SystemMonitor::Get()->ProcessDevicesChanged(device_type);
  84 }
  85
  86 }  // namespace content