Do not show notifications when in fullscreen or screensaver mode....

chrome/browser/idle_linux.cc

 // Copyright (c) 2010 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/idle.h"
 
+#include <gdk/gdk.h>
+#include <gdk/gdkx.h>
+
+#include <vector>
+
+#include "base/basictypes.h"
 #include "chrome/browser/sync/engine/idle_query_linux.h"
+#include "chrome/browser/ui/gtk/gtk_util.h"
+#include "ui/base/x/x11_util.h"
+
+namespace {
+
+class ScreensaverWindowFinder : public ui::EnumerateWindowsDelegate {
+ public:
+  ScreensaverWindowFinder()
+      : exists_(false) {}
+
+  bool exists() const { return exists_; }
+
+ protected:
+  virtual bool ShouldStopIterating(XID window) {
+    if (!ui::IsWindowVisible(window) || !isScreensaverWindow(window))
+      return false;
+    exists_ = true;
+    return true;
+  }
+
+ private:
+  bool isScreensaverWindow(XID window) const {

[Daniel Erat, 2011/01/24 19:54:57]

should be "IsScreensaverWindow"

[jianli, 2011/01/24 23:36:26]

Done.

+    // It should occupy full screen.

[Daniel Erat, 2011/01/24 19:54:57]

s/occupy full/occupy the full/

[jianli, 2011/01/24 23:36:26]

Done.

+    if (!ui::IsX11WindowFullScreen(window))
+      return false;
+
+    // For xscreensaver, the window should have _SCREENSAVER_VERSION property.
+    if (ui::PropertyExists(window, "_SCREENSAVER_VERSION"))
+      return true;
+
+    // For all others, like gnome-screensaver, the window's WM_CLASS property
+    // should contains "screensaver".

[Daniel Erat, 2011/01/24 19:54:57]

s/contains/contain/

[jianli, 2011/01/24 23:36:26]

Done.

+    std::string value;
+    if (ui::GetStringProperty(window, "WM_CLASS", &value)) {
+      size_t pos = 0, len = value.length();

[Daniel Erat, 2011/01/24 19:54:57]

I don't understand why you're stepping through the string here.  A single call
to value.find("screensaver") be sufficient if you just want to see if
"screensaver" occurs somewhere in |value|.

[jianli, 2011/01/24 23:36:26]

WM_CLASS property (per http://tronche.com/gui/x/icccm/sec-4.html#WM_CLASS)
contains two consecutive null-terminated strings. Previously I thought
std::string:find() is not able to find the pattern in the 2nd C-string. But it
turned out it worked fine. So I changed to call value.find() as you suggested.

+      while (pos < len) {
+        std::string str(value.c_str() + pos);
+        if (str.find("screensaver") != std::string::npos)
+          return true;
+        pos += str.length() + 1;

[Daniel Erat, 2011/01/24 19:54:57]

Additionally, isn't this wrong?  str.length() should be equal to value.length()
(additional nit: I think that size() is the more common name), so I think you'd
only ever go through the loop a single time.

[jianli, 2011/01/24 23:36:26]

Removed. See last comment.

+      }
+    }
+
+    return false;
+  }
+
+  bool exists_;
+
+  DISALLOW_COPY_AND_ASSIGN(ScreensaverWindowFinder);
+};
+
+bool ExistsScreensaverWindow() {

[Daniel Erat, 2011/01/24 19:54:57]

nit: rename to ScreensaverWindowExists() (but since this function is tiny and
only appears to get called in one place, I'd probably just move it into
IsScreensaverRunning())

[jianli, 2011/01/24 23:36:26]

Done.

[Daniel Erat, 2011/01/25 00:34:32]

Is it?  I still see the old name.

+  ScreensaverWindowFinder finder;
+  gtk_util::EnumerateTopLevelWindows(&finder);
+  return finder.exists();
+}
+
+bool IsScreensaverRunning() {
+  gdk_error_trap_push();
+  bool result = ExistsScreensaverWindow();
+  bool got_error = gdk_error_trap_pop();
+  return result && !got_error;
+}
+
+}
 
 IdleState CalculateIdleState(unsigned int idle_threshold) {
+  // Usually screensaver is used to lock the screen. So we do not need to check

[Daniel Erat, 2011/01/24 19:54:57]

minor grammatical nits:

s/Usually screensaver/Usually the screensaver/
s/screen\. So/screen, so/

[jianli, 2011/01/24 23:36:26]

Done.

+  // if the workstation is locked.
+  if (IsScreensaverRunning())
+    return IDLE_STATE_LOCKED;
+
   browser_sync::IdleQueryLinux idle_query;
   unsigned int idle_time = idle_query.IdleTime();
   if (idle_time >= idle_threshold)
     return IDLE_STATE_IDLE;
   return IDLE_STATE_ACTIVE;
 }