content/browser/power_save_blocker_x11.cc

   1 // Copyright (c) 2012 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/power_save_blocker_impl.h"
   6
   7 #include <X11/Xlib.h>
   8 #include <X11/extensions/dpms.h>
   9 // Xlib #defines Status, but we can't have that for some of our headers.
  10 #ifdef Status
  11 #undef Status
  12 #endif
  13
  14 #include "base/basictypes.h"
  15 #include "base/bind.h"
  16 #include "base/callback.h"
  17 #include "base/command_line.h"
  18 #include "base/environment.h"
  19 #include "base/files/file_path.h"
  20 #include "base/logging.h"
  21 #include "base/memory/ref_counted.h"
  22 #include "base/memory/scoped_ptr.h"
  23 #include "base/memory/singleton.h"
  24 #include "base/message_loop/message_loop_proxy.h"
  25 #include "base/nix/xdg_util.h"
  26 #include "base/synchronization/lock.h"
  27 #include "content/public/browser/browser_thread.h"
  28 #include "dbus/bus.h"
  29 #include "dbus/message.h"
  30 #include "dbus/object_path.h"
  31 #include "dbus/object_proxy.h"
  32 #include "ui/gfx/x/x11_types.h"
  33
  34 namespace {
  35
  36 enum DBusAPI {
  37   NO_API,           // Disable. No supported API available.
  38   GNOME_API,        // Use the GNOME API. (Supports more features.)
  39   FREEDESKTOP_API,  // Use the FreeDesktop API, for KDE4 and XFCE.
  40 };
  41
  42 // Inhibit flags defined in the org.gnome.SessionManager interface.
  43 // Can be OR'd together and passed as argument to the Inhibit() method
  44 // to specify which power management features we want to suspend.
  45 enum GnomeAPIInhibitFlags {
  46   INHIBIT_LOGOUT            = 1,
  47   INHIBIT_SWITCH_USER       = 2,
  48   INHIBIT_SUSPEND_SESSION   = 4,
  49   INHIBIT_MARK_SESSION_IDLE = 8
  50 };
  51
  52 const char kGnomeAPIServiceName[] = "org.gnome.SessionManager";
  53 const char kGnomeAPIInterfaceName[] = "org.gnome.SessionManager";
  54 const char kGnomeAPIObjectPath[] = "/org/gnome/SessionManager";
  55
  56 const char kFreeDesktopAPIServiceName[] = "org.freedesktop.PowerManagement";
  57 const char kFreeDesktopAPIInterfaceName[] =
  58     "org.freedesktop.PowerManagement.Inhibit";
  59 const char kFreeDesktopAPIObjectPath[] =
  60     "/org/freedesktop/PowerManagement/Inhibit";
  61
  62 }  // namespace
  63
  64 namespace content {
  65
  66 class PowerSaveBlockerImpl::Delegate
  67     : public base::RefCountedThreadSafe<PowerSaveBlockerImpl::Delegate> {
  68  public:
  69   // Picks an appropriate D-Bus API to use based on the desktop environment.
  70   Delegate(PowerSaveBlockerType type, const std::string& reason);
  71
  72   // Post a task to initialize the delegate on the UI thread, which will itself
  73   // then post a task to apply the power save block on the FILE thread.
  74   void Init();
  75
  76   // Post a task to remove the power save block on the FILE thread, unless it
  77   // hasn't yet been applied, in which case we just prevent it from applying.
  78   void CleanUp();
  79
  80  private:
  81   friend class base::RefCountedThreadSafe<Delegate>;
  82   ~Delegate() {}
  83
  84   // Selects an appropriate D-Bus API to use for this object. Must be called on
  85   // the UI thread. Checks enqueue_apply_ once an API has been selected, and
  86   // enqueues a call back to ApplyBlock() if it is true. See the comments for
  87   // enqueue_apply_ below.
  88   void InitOnUIThread();
  89
  90   // Apply or remove the power save block, respectively. These methods should be
  91   // called once each, on the same thread, per instance. They block waiting for
  92   // the action to complete (with a timeout); the thread must thus allow I/O.
  93   void ApplyBlock(DBusAPI api);
  94   void RemoveBlock(DBusAPI api);
  95
  96   // If DPMS (the power saving system in X11) is not enabled, then we don't want
  97   // to try to disable power saving, since on some desktop environments that may
  98   // enable DPMS with very poor default settings (e.g. turning off the display
  99   // after only 1 second). Must be called on the UI thread.
 100   static bool DPMSEnabled();
 101
 102   // Returns an appropriate D-Bus API to use based on the desktop environment.
 103   // Must be called on the UI thread, as it may call DPMSEnabled() above.
 104   static DBusAPI SelectAPI();
 105
 106   const PowerSaveBlockerType type_;
 107   const std::string reason_;
 108
 109   // Initially, we post a message to the UI thread to select an API. When it
 110   // finishes, it will post a message to the FILE thread to perform the actual
 111   // application of the block, unless enqueue_apply_ is false. We set it to
 112   // false when we post that message, or when RemoveBlock() is called before
 113   // ApplyBlock() has run. Both api_ and enqueue_apply_ are guarded by lock_.
 114   DBusAPI api_;
 115   bool enqueue_apply_;
 116   base::Lock lock_;
 117
 118   scoped_refptr<dbus::Bus> bus_;
 119
 120   // The cookie that identifies our inhibit request,
 121   // or 0 if there is no active inhibit request.
 122   uint32 inhibit_cookie_;
 123
 124   DISALLOW_COPY_AND_ASSIGN(Delegate);
 125 };
 126
 127 PowerSaveBlockerImpl::Delegate::Delegate(PowerSaveBlockerType type,
 128                                          const std::string& reason)
 129     : type_(type),
 130       reason_(reason),
 131       api_(NO_API),
 132       enqueue_apply_(false),
 133       inhibit_cookie_(0) {
 134   // We're on the client's thread here, so we don't allocate the dbus::Bus
 135   // object yet. We'll do it later in ApplyBlock(), on the FILE thread.
 136 }
 137
 138 void PowerSaveBlockerImpl::Delegate::Init() {
 139   base::AutoLock lock(lock_);
 140   DCHECK(!enqueue_apply_);
 141   enqueue_apply_ = true;
 142   BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
 143                           base::Bind(&Delegate::InitOnUIThread, this));
 144 }
 145
 146 void PowerSaveBlockerImpl::Delegate::CleanUp() {
 147   base::AutoLock lock(lock_);
 148   if (enqueue_apply_) {
 149     // If a call to ApplyBlock() has not yet been enqueued because we are still
 150     // initializing on the UI thread, then just cancel it. We don't need to
 151     // remove the block because we haven't even applied it yet.
 152     enqueue_apply_ = false;
 153   } else if (api_ != NO_API) {
 154     BrowserThread::PostTask(BrowserThread::FILE, FROM_HERE,
 155                             base::Bind(&Delegate::RemoveBlock, this, api_));
 156   }
 157 }
 158
 159 void PowerSaveBlockerImpl::Delegate::InitOnUIThread() {
 160   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 161   base::AutoLock lock(lock_);
 162   api_ = SelectAPI();
 163   if (enqueue_apply_ && api_ != NO_API) {
 164     // The thread we use here becomes the origin and D-Bus thread for the D-Bus
 165     // library, so we need to use the same thread above for RemoveBlock(). It
 166     // must be a thread that allows I/O operations, so we use the FILE thread.
 167     BrowserThread::PostTask(BrowserThread::FILE, FROM_HERE,
 168                             base::Bind(&Delegate::ApplyBlock, this, api_));
 169   }
 170   enqueue_apply_ = false;
 171 }
 172
 173 void PowerSaveBlockerImpl::Delegate::ApplyBlock(DBusAPI api) {
 174   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
 175   DCHECK(!bus_.get());  // ApplyBlock() should only be called once.
 176
 177   dbus::Bus::Options options;
 178   options.bus_type = dbus::Bus::SESSION;
 179   options.connection_type = dbus::Bus::PRIVATE;
 180   bus_ = new dbus::Bus(options);
 181
 182   scoped_refptr<dbus::ObjectProxy> object_proxy;
 183   scoped_ptr<dbus::MethodCall> method_call;
 184   scoped_ptr<dbus::MessageWriter> message_writer;
 185
 186   switch (api) {
 187     case NO_API:
 188       NOTREACHED();  // We should never call this method with this value.
 189       return;
 190     case GNOME_API:
 191       object_proxy = bus_->GetObjectProxy(
 192           kGnomeAPIServiceName,
 193           dbus::ObjectPath(kGnomeAPIObjectPath));
 194       method_call.reset(
 195           new dbus::MethodCall(kGnomeAPIInterfaceName, "Inhibit"));
 196       message_writer.reset(new dbus::MessageWriter(method_call.get()));
 197       // The arguments of the method are:
 198       //     app_id:        The application identifier
 199       //     toplevel_xid:  The toplevel X window identifier
 200       //     reason:        The reason for the inhibit
 201       //     flags:         Flags that spefify what should be inhibited
 202       message_writer->AppendString(
 203           base::CommandLine::ForCurrentProcess()->GetProgram().value());
 204       message_writer->AppendUint32(0);  // should be toplevel_xid
 205       message_writer->AppendString(reason_);
 206       {
 207         uint32 flags = 0;
 208         switch (type_) {
 209           case kPowerSaveBlockPreventDisplaySleep:
 210             flags |= INHIBIT_MARK_SESSION_IDLE;
 211             flags |= INHIBIT_SUSPEND_SESSION;
 212             break;
 213           case kPowerSaveBlockPreventAppSuspension:
 214             flags |= INHIBIT_SUSPEND_SESSION;
 215             break;
 216         }
 217         message_writer->AppendUint32(flags);
 218       }
 219       break;
 220     case FREEDESKTOP_API:
 221       object_proxy = bus_->GetObjectProxy(
 222           kFreeDesktopAPIServiceName,
 223           dbus::ObjectPath(kFreeDesktopAPIObjectPath));
 224       method_call.reset(
 225           new dbus::MethodCall(kFreeDesktopAPIInterfaceName, "Inhibit"));
 226       message_writer.reset(new dbus::MessageWriter(method_call.get()));
 227       // The arguments of the method are:
 228       //     app_id:        The application identifier
 229       //     reason:        The reason for the inhibit
 230       message_writer->AppendString(
 231           base::CommandLine::ForCurrentProcess()->GetProgram().value());
 232       message_writer->AppendString(reason_);
 233       break;
 234   }
 235
 236   // We could do this method call asynchronously, but if we did, we'd need to
 237   // handle the case where we want to cancel the block before we get a reply.
 238   // We're on the FILE thread so it should be OK to block briefly here.
 239   scoped_ptr<dbus::Response> response(object_proxy->CallMethodAndBlock(
 240       method_call.get(), dbus::ObjectProxy::TIMEOUT_USE_DEFAULT));
 241   if (response) {
 242     // The method returns an inhibit_cookie, used to uniquely identify
 243     // this request. It should be used as an argument to Uninhibit()
 244     // in order to remove the request.
 245     dbus::MessageReader message_reader(response.get());
 246     if (!message_reader.PopUint32(&inhibit_cookie_))
 247       LOG(ERROR) << "Invalid Inhibit() response: " << response->ToString();
 248   } else {
 249     LOG(ERROR) << "No response to Inhibit() request!";
 250   }
 251 }
 252
 253 void PowerSaveBlockerImpl::Delegate::RemoveBlock(DBusAPI api) {
 254   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
 255   DCHECK(bus_.get());  // RemoveBlock() should only be called once.
 256
 257   scoped_refptr<dbus::ObjectProxy> object_proxy;
 258   scoped_ptr<dbus::MethodCall> method_call;
 259
 260   switch (api) {
 261     case NO_API:
 262       NOTREACHED();  // We should never call this method with this value.
 263       return;
 264     case GNOME_API:
 265       object_proxy = bus_->GetObjectProxy(
 266           kGnomeAPIServiceName,
 267           dbus::ObjectPath(kGnomeAPIObjectPath));
 268       method_call.reset(
 269           new dbus::MethodCall(kGnomeAPIInterfaceName, "Uninhibit"));
 270       break;
 271     case FREEDESKTOP_API:
 272       object_proxy = bus_->GetObjectProxy(
 273           kFreeDesktopAPIServiceName,
 274           dbus::ObjectPath(kFreeDesktopAPIObjectPath));
 275       method_call.reset(
 276           new dbus::MethodCall(kFreeDesktopAPIInterfaceName, "UnInhibit"));
 277       break;
 278   }
 279
 280   dbus::MessageWriter message_writer(method_call.get());
 281   message_writer.AppendUint32(inhibit_cookie_);
 282   scoped_ptr<dbus::Response> response(object_proxy->CallMethodAndBlock(
 283       method_call.get(), dbus::ObjectProxy::TIMEOUT_USE_DEFAULT));
 284   if (!response)
 285     LOG(ERROR) << "No response to Uninhibit() request!";
 286   // We don't care about checking the result. We assume it works; we can't
 287   // really do anything about it anyway if it fails.
 288   inhibit_cookie_ = 0;
 289
 290   bus_->ShutdownAndBlock();
 291   bus_ = NULL;
 292 }
 293
 294 // static
 295 bool PowerSaveBlockerImpl::Delegate::DPMSEnabled() {
 296   XDisplay* display = gfx::GetXDisplay();
 297   BOOL enabled = false;
 298   int dummy;
 299   if (DPMSQueryExtension(display, &dummy, &dummy) && DPMSCapable(display)) {
 300     CARD16 state;
 301     DPMSInfo(display, &state, &enabled);
 302   }
 303   return enabled;
 304 }
 305
 306 // static
 307 DBusAPI PowerSaveBlockerImpl::Delegate::SelectAPI() {
 308   scoped_ptr<base::Environment> env(base::Environment::Create());
 309   switch (base::nix::GetDesktopEnvironment(env.get())) {
 310     case base::nix::DESKTOP_ENVIRONMENT_GNOME:
 311     case base::nix::DESKTOP_ENVIRONMENT_UNITY:
 312       if (DPMSEnabled())
 313         return GNOME_API;
 314       break;
 315     case base::nix::DESKTOP_ENVIRONMENT_XFCE:
 316     case base::nix::DESKTOP_ENVIRONMENT_KDE4:
 317       if (DPMSEnabled())
 318         return FREEDESKTOP_API;
 319       break;
 320     case base::nix::DESKTOP_ENVIRONMENT_KDE3:
 321     case base::nix::DESKTOP_ENVIRONMENT_OTHER:
 322       // Not supported.
 323       break;
 324   }
 325   return NO_API;
 326 }
 327
 328 PowerSaveBlockerImpl::PowerSaveBlockerImpl(
 329     PowerSaveBlockerType type, const std::string& reason)
 330     : delegate_(new Delegate(type, reason)) {
 331   delegate_->Init();
 332 }
 333
 334 PowerSaveBlockerImpl::~PowerSaveBlockerImpl() {
 335   delegate_->CleanUp();
 336 }
 337
 338 }  // namespace content