Implement the idle timer for Linux using libxss.

BUG=2183

Review URL: http://codereview.chromium.org/8806

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@4930 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 66 insertions, 0 deletions

diff --git a/base/base_lib.scons b/base/base_lib.scons
index 89d0d6e..487d5d8 100644
--- a/base/base_lib.scons
+++ b/base/base_lib.scons
@@ -96,7 +96,11 @@ if env['PLATFORM'] in ('posix', 'darwin'):
     'file_version_info.cc',
 
     # This group all depends on MessageLoop.
+
+    # We have an implementation of idle_timer, but it's unclear if we want it
+    # yet, so it's commented out for now.  Leave this 'unported'.
     'idle_timer.cc',
+
     'object_watcher.cc',
     'watchdog.cc',
 
diff --git a/base/base_unittests.scons b/base/base_unittests.scons
index aedad49..7b1cc28 100644
--- a/base/base_unittests.scons
+++ b/base/base_unittests.scons
@@ -61,6 +61,7 @@ if env['PLATFORM'] == 'win32':
 
 if env['PLATFORM'] == 'posix':
   env.Append(
+      # We need 'Xss' (X Screen Saver) in LIBS if we want idletimer_unittest
       LIBS = [
           'event',
       ],
@@ -133,7 +134,10 @@ if env['PLATFORM'] in ('posix', 'darwin'):
   # Remove files that still need to be ported from the input_files list.
   # TODO(port): delete files from this list as they get ported.
   to_be_ported_files = [
+      # We have an implementation of idle_timer, but it's unclear if we want it
+      # yet, so it's commented out for now.  Leave this 'unported'.
       'idletimer_unittest.cc',
+
       'watchdog_unittest.cc',
       'gfx/native_theme_unittest.cc',
       'gfx/uniscribe_unittest.cc',
diff --git a/base/idle_timer.cc b/base/idle_timer.cc
index 5d9670d..5e6bda7 100644
--- a/base/idle_timer.cc
+++ b/base/idle_timer.cc
@@ -4,10 +4,24 @@
 
 #include "base/idle_timer.h"
 
+// We may not want to port idle_timer to Linux, but we have implemented it
+// anyway.  Define this to 1 to enable the Linux idle timer and then add the
+// libs that need to be linked (Xss).
+#define ENABLE_XSS_SUPPORT 0
+
 #if defined(OS_MACOSX)
 #include <ApplicationServices/ApplicationServices.h>
 #endif
 
+#if defined(OS_LINUX) && ENABLE_XSS_SUPPORT
+// We may not want to port idle_timer to Linux, but we have implemented it
+// anyway.  Remove the 0 above if we want it.
+#include <gdk/gdkx.h>
+#include <X11/extensions/scrnsaver.h>
+#include "base/lazy_instance.h"
+#include "base/thread_local.h"
+#endif
+
 #include "base/message_loop.h"
 #include "base/time.h"
 
@@ -40,6 +54,50 @@ bool OSIdleTimeSource(int32 *milliseconds_interval_since_last_event) {
           kCGAnyInputEventType) * 1000.0;
   return true;
 }
+#elif defined(OS_LINUX) && ENABLE_XSS_SUPPORT
+class IdleState {
+ public:
+  IdleState() {
+    int event_base, error_base;
+    have_idle_info_ = XScreenSaverQueryExtension(GDK_DISPLAY(), &event_base,
+                                                 &error_base);
+    if (have_idle_info_)
+      *idle_info_.Get() = XScreenSaverAllocInfo();
+  }
+
+  ~IdleState() {
+    if (*idle_info_.Get()) {
+      XFree(*idle_info_.Get());
+      idle_info_.~ThreadLocalPointer();
+    }
+  }
+
+  int32 IdleTime() {
+    if (have_idle_info_ && idle_info_.Get()) {
+      XScreenSaverQueryInfo(GDK_DISPLAY(), GDK_ROOT_WINDOW(),
+                            *idle_info_.Get());
+      return (*idle_info_.Get())->idle;
+    }
+    return -1;
+  }
+
+ private:
+  bool have_idle_info_;
+  ThreadLocalPointer<XScreenSaverInfo*> idle_info_;
+
+  DISALLOW_COPY_AND_ASSIGN(IdleState);
+};
+
+bool OSIdleTimeSource(int32* milliseconds_interval_since_last_event) {
+  static LazyInstance<IdleState> state_instance(base::LINKER_INITIALIZED);
+  IdleState* state = state_instance.Pointer();
+  int32 idle_time = state->IdleTime();
+  if (0 < idle_time) {
+    *milliseconds_interval_since_last_event = idle_time;
+    return true;
+  }
+  return false;
+}
 #endif
 
 IdleTimer::IdleTimer(TimeDelta idle_time, bool repeat)