Initialize XInput2 on demand

base/message_pump_x.cc

Index: base/message_pump_x.cc
diff --git a/base/message_pump_x.cc b/base/message_pump_x.cc
index e7deff0f602316625093be29971493743f3acf22..c19e3cbb931063231eb8a09947b65e5a1014853d 100644
--- a/base/message_pump_x.cc
+++ b/base/message_pump_x.cc
@@ -37,8 +37,9 @@ GSourceFuncs XSourceFuncs = {
   NULL
 };
 
-// The opcode used for checking events.
-int xiopcode = -1;
+// The status of XInput2 initialization.
+bool xInput2Initialized = false;

[sadrul, 2012/05/16 21:47:12]

xinput2_initialized
xinput2_supported

camelCase is for webKit!

[Rick Byers, 2012/05/17 14:06:56]

Done.

+bool xInput2Supported = false;
 
 // The message-pump opens a connection to the display and owns it.
 Display* g_xdisplay = NULL;
@@ -47,16 +48,20 @@ Display* g_xdisplay = NULL;
 // is specified.
 base::MessagePumpDispatcher* g_default_dispatcher = NULL;
 
-void InitializeXInput2(void) {
+void InitializeXInput2IfNeeded(void) {
+  if (xInput2Initialized)
+    return;
+  xInput2Initialized = true;
+
   Display* display = base::MessagePumpX::GetDefaultXDisplay();
   if (!display)
     return;
 
   int event, err;
 
+  int xiopcode;
   if (!XQueryExtension(display, "XInputExtension", &xiopcode, &event, &err)) {
     DVLOG(1) << "X Input extension not available.";
-    xiopcode = -1;
     return;
   }
 
@@ -68,17 +73,17 @@ void InitializeXInput2(void) {
 #endif
   if (XIQueryVersion(display, &major, &minor) == BadRequest) {
     DVLOG(1) << "XInput2 not supported in the server.";
-    xiopcode = -1;
     return;
   }
 #if defined(USE_XI2_MT)
   if (major < 2 || (major == 2 && minor < USE_XI2_MT)) {
     DVLOG(1) << "XI version on server is " << major << "." << minor << ". "
             << "But 2." << USE_XI2_MT << " is required.";
-    xiopcode = -1;
     return;
   }
 #endif
+
+  xInput2Supported = true;
 }
 
 }  // namespace
@@ -87,7 +92,7 @@ namespace base {
 
 MessagePumpX::MessagePumpX() : MessagePumpGlib(),
     x_source_(NULL) {
-  InitializeXInput2();
+  InitializeXInput2IfNeeded();
   InitXSource();
 }
 
@@ -107,7 +112,8 @@ Display* MessagePumpX::GetDefaultXDisplay() {
 
 // static
 bool MessagePumpX::HasXInput2() {
-  return xiopcode != -1;
+  InitializeXInput2IfNeeded();
+  return xInput2Supported;
 }
 
 // static