Handling cursor visibility changing events for ChromeOS

The CL does 4 things:
1. A handler in RootWindowHost that will be called whenever cursor
visibility is changed.
2. Temporarily pause trackpad tap-to-click feature when the cursor
is hidden.
3. Add a cache class that caches X input device lists to minimize
round-trip time to X server for device list queries.
4. Refactor around the places where XListInputDevices/XIQueryDevice
queries are used.

Contributed by sheckylin@chromium.org

BUG=chromium:156697,chrome-os-partner:14085
TEST=Tested on link. "Tap paused" was successfully set when visibility
changed.

Change-Id: Ia5c62f821c80efc973e3b1ce54a467b674b466a4

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=171223

Reverted: https://codereview.chromium.org/11454002/


Review URL: https://chromiumcodereview.appspot.com/11316074

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@171928 0039d316-1c4b-4281-b951-d872f2087c98

4 files changed, 139 insertions, 21 deletions

diff --git a/ui/base/x/device_list_cache_x.cc b/ui/base/x/device_list_cache_x.cc
new file mode 100644
index 0000000..9fcb9db
--- /dev/null
+++ b/ui/base/x/device_list_cache_x.cc
@@ -0,0 +1,61 @@
+// Copyright (c) 2012 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 "ui/base/x/device_list_cache_x.h"
+
+#include <algorithm>
+
+#include "base/memory/singleton.h"
+#include "ui/base/x/x11_util.h"
+
+namespace ui {
+
+DeviceListCacheX::DeviceListCacheX() {
+}
+
+DeviceListCacheX::~DeviceListCacheX() {
+  std::map<Display*, XDeviceList>::iterator xp;
+  for (xp = x_dev_list_map_.begin(); xp != x_dev_list_map_.end(); xp++)
+    XFreeDeviceList(xp->second.devices);
+  std::map<Display*, XIDeviceList>::iterator xip;
+  for (xip = xi_dev_list_map_.begin(); xip != xi_dev_list_map_.end(); xip++)
+    XIFreeDeviceInfo(xip->second.devices);
+}
+
+DeviceListCacheX* DeviceListCacheX::GetInstance() {
+  return Singleton<DeviceListCacheX>::get();
+}
+
+void DeviceListCacheX::UpdateDeviceList(Display* display) {
+  XDeviceList& new_x_dev_list = x_dev_list_map_[display];
+  if (new_x_dev_list.devices)
+    XFreeDeviceList(new_x_dev_list.devices);
+  new_x_dev_list.devices = XListInputDevices(display, &new_x_dev_list.count);
+
+  XIDeviceList& new_xi_dev_list = xi_dev_list_map_[display];
+  if (new_xi_dev_list.devices)
+    XIFreeDeviceInfo(new_xi_dev_list.devices);
+  new_xi_dev_list.devices = XIQueryDevice(display, XIAllDevices,
+                                         &new_xi_dev_list.count);
+}
+
+const XDeviceList& DeviceListCacheX::GetXDeviceList(Display* display) {
+  XDeviceList& x_dev_list = x_dev_list_map_[display];
+  // Note that the function can be called before any update has taken place.
+  if (!x_dev_list.devices && !x_dev_list.count)
+    x_dev_list.devices = XListInputDevices(display, &x_dev_list.count);
+  return x_dev_list;
+}
+
+const XIDeviceList& DeviceListCacheX::GetXI2DeviceList(Display* display) {
+  XIDeviceList& xi_dev_list = xi_dev_list_map_[display];
+  if (!xi_dev_list.devices && !xi_dev_list.count) {
+    xi_dev_list.devices = XIQueryDevice(display, XIAllDevices,
+                                       &xi_dev_list.count);
+  }
+  return xi_dev_list;
+}
+
+}  // namespace ui
+
diff --git a/ui/base/x/device_list_cache_x.h b/ui/base/x/device_list_cache_x.h
new file mode 100644
index 0000000..2b3cefa
--- /dev/null
+++ b/ui/base/x/device_list_cache_x.h
@@ -0,0 +1,63 @@
+// Copyright (c) 2012 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.
+
+#ifndef UI_BASE_X_DEVICE_LIST_CACHE_X_H_
+#define UI_BASE_X_DEVICE_LIST_CACHE_X_H_
+
+#include <X11/extensions/XInput.h>
+#include <X11/extensions/XInput2.h>
+
+#include <map>
+
+#include "base/basictypes.h"
+#include "ui/base/ui_export.h"
+
+template <typename T> struct DefaultSingletonTraits;
+
+typedef struct _XDisplay Display;
+
+template <typename T>
+struct DeviceList {
+  DeviceList() : devices(NULL), count(0) {
+  }
+  T& operator[] (int x) {
+    return devices[x];
+  }
+  T* devices;
+  int count;
+};
+
+typedef struct DeviceList<XDeviceInfo> XDeviceList;
+typedef struct DeviceList<XIDeviceInfo> XIDeviceList;
+
+namespace ui {
+
+// A class to cache the current XInput device list. This minimized the
+// round-trip time to the X server whenever such a device list is needed. The
+// update function will be called on each incoming XI_HierarchyChanged event.
+class UI_EXPORT DeviceListCacheX {
+ public:
+  static DeviceListCacheX* GetInstance();
+
+  void UpdateDeviceList(Display* display);
+
+  const XDeviceList& GetXDeviceList(Display* display);
+  const XIDeviceList& GetXI2DeviceList(Display* display);
+
+ private:
+  friend struct DefaultSingletonTraits<DeviceListCacheX>;
+
+  DeviceListCacheX();
+  ~DeviceListCacheX();
+
+  std::map<Display*, XDeviceList> x_dev_list_map_;
+  std::map<Display*, XIDeviceList> xi_dev_list_map_;
+
+  DISALLOW_COPY_AND_ASSIGN(DeviceListCacheX);
+};
+
+}  // namespace ui
+
+#endif  // UI_BASE_X_DEVICE_LIST_CACHE_X_H_
+
diff --git a/ui/base/x/events_x.cc b/ui/base/x/events_x.cc
index 9aa84d7..116b867 100644
--- a/ui/base/x/events_x.cc
+++ b/ui/base/x/events_x.cc
@@ -19,6 +19,7 @@
 #include "ui/base/keycodes/keyboard_code_conversion_x.h"
 #include "ui/base/touch/touch_factory.h"
 #include "ui/base/ui_base_switches.h"
+#include "ui/base/x/device_list_cache_x.h"
 #include "ui/base/x/valuators.h"
 #include "ui/base/x/x11_atom_cache.h"
 #include "ui/base/x/x11_util.h"
@@ -98,20 +99,16 @@ class CMTEventData {
     device_to_valuators_.clear();
 
 #if defined(USE_XI2_MT)
-    int count = 0;
-
     // Find all the touchpad devices.
-    XDeviceInfo* dev_list = XListInputDevices(display, &count);
+    XDeviceList dev_list =
+        ui::DeviceListCacheX::GetInstance()->GetXDeviceList(display);
     Atom xi_touchpad = XInternAtom(display, XI_TOUCHPAD, false);
-    for (int i = 0; i < count; ++i) {
-      XDeviceInfo* dev = dev_list + i;
-      if (dev->type == xi_touchpad)
+    for (int i = 0; i < dev_list.count; ++i)
+      if (dev_list[i].type == xi_touchpad)
         touchpads_[dev_list[i].id] = true;
-    }
-    if (dev_list)
-      XFreeDeviceList(dev_list);
 
-    XIDeviceInfo* info_list = XIQueryDevice(display, XIAllDevices, &count);
+    XIDeviceList info_list =
+        ui::DeviceListCacheX::GetInstance()->GetXI2DeviceList(display);
     Atom x_axis = atom_cache_.GetAtom(AXIS_LABEL_PROP_REL_HWHEEL);
     Atom y_axis = atom_cache_.GetAtom(AXIS_LABEL_PROP_REL_WHEEL);
     Atom start_time = atom_cache_.GetAtom(AXIS_LABEL_PROP_ABS_START_TIME);
@@ -126,8 +123,8 @@ class CMTEventData {
     Atom fling_state = atom_cache_.GetAtom(AXIS_LABEL_PROP_ABS_FLING_STATE);
     Atom finger_count = atom_cache_.GetAtom(AXIS_LABEL_PROP_ABS_FINGER_COUNT);
 
-    for (int i = 0; i < count; ++i) {
-      XIDeviceInfo* info = info_list + i;
+    for (int i = 0; i < info_list.count; ++i) {
+      XIDeviceInfo* info = info_list.devices + i;
 
       if (info->use != XISlavePointer && info->use != XIFloatingSlave)
         continue;
@@ -199,8 +196,6 @@ class CMTEventData {
         cmt_devices_[info->deviceid] = true;
       }
     }
-    if (info_list)
-      XIFreeDeviceInfo(info_list);
 #endif  // defined(USE_XI2_MT)
   }
 
@@ -704,6 +699,7 @@ namespace ui {
 
 void UpdateDeviceList() {
   Display* display = GetXDisplay();
+  DeviceListCacheX::GetInstance()->UpdateDeviceList(display);
   CMTEventData::GetInstance()->UpdateDeviceList(display);
   TouchFactory::GetInstance()->UpdateDeviceList(display);
   ValuatorTracker::GetInstance()->SetupValuator();
diff --git a/ui/base/x/valuators.cc b/ui/base/x/valuators.cc
index 2380d84..4008b36 100644
--- a/ui/base/x/valuators.cc
+++ b/ui/base/x/valuators.cc
@@ -8,6 +8,7 @@
 
 #include "base/memory/singleton.h"
 #include "ui/base/touch/touch_factory.h"
+#include "ui/base/x/device_list_cache_x.h"
 #include "ui/base/x/x11_util.h"
 
 namespace {
@@ -158,12 +159,12 @@ void ValuatorTracker::SetupValuator() {
   memset(last_seen_valuator_, 0, sizeof(last_seen_valuator_));
 
   Display* display = GetXDisplay();
-  int ndevice;
-  XIDeviceInfo* info_list = XIQueryDevice(display, XIAllDevices, &ndevice);
+  XIDeviceList info_list =
+      DeviceListCacheX::GetInstance()->GetXI2DeviceList(display);
   TouchFactory* factory = TouchFactory::GetInstance();
 
-  for (int i = 0; i < ndevice; i++) {
-    XIDeviceInfo* info = info_list + i;
+  for (int i = 0; i < info_list.count; i++) {
+    XIDeviceInfo* info = info_list.devices + i;
 
     if (!factory->IsTouchDevice(info->deviceid))
       continue;
@@ -178,9 +179,6 @@ void ValuatorTracker::SetupValuator() {
       }
     }
   }
-
-  if (info_list)
-    XIFreeDeviceInfo(info_list);
 }
 
 }  // namespace ui