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