From 6e8c0095d0410a30ffa06bb0b0cb71f979becfb0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Trond=20Kjern=C3=A5sen?= <trond@trolltech.com>
Date: Fri, 12 Mar 2010 12:49:38 +0100
Subject: Made QGLExtensions::glExtensions() thread-safe.

Reviewed-by: Gunnar
---
 src/opengl/qgl.cpp | 37 ++++++++++++++++++-------------------
 src/opengl/qgl_p.h |  2 --
 2 files changed, 18 insertions(+), 21 deletions(-)

diff --git a/src/opengl/qgl.cpp b/src/opengl/qgl.cpp
index 58ac642..e0030ad 100644
--- a/src/opengl/qgl.cpp
+++ b/src/opengl/qgl.cpp
@@ -5060,6 +5060,20 @@ QGLExtensions::Extensions QGLExtensions::currentContextExtensions()
     return glExtensions;
 }
 
+
+class QGLDefaultExtensions
+{
+public:
+    QGLDefaultExtensions() {
+        QGLTemporaryContext tempContext;
+        extensions = QGLExtensions::currentContextExtensions();
+    }
+
+    QGLExtensions::Extensions extensions;
+};
+
+Q_GLOBAL_STATIC(QGLDefaultExtensions, qtDefaultExtensions)
+
 /*
     Returns the GL extensions for the current QGLContext. If there is no
     current QGLContext, a default context will be created and the extensions
@@ -5067,34 +5081,19 @@ QGLExtensions::Extensions QGLExtensions::currentContextExtensions()
 */
 QGLExtensions::Extensions QGLExtensions::glExtensions()
 {
-    QGLTemporaryContext *tmpContext = 0;
-    static bool cachedDefault = false;
-    static Extensions defaultExtensions = 0;
+    Extensions extensionFlags = 0;
     QGLContext *currentCtx = const_cast<QGLContext *>(QGLContext::currentContext());
 
     if (currentCtx && currentCtx->d_func()->extension_flags_cached)
         return currentCtx->d_func()->extension_flags;
 
     if (!currentCtx) {
-        if (cachedDefault) {
-            return defaultExtensions;
-        } else {
-            tmpContext = new QGLTemporaryContext;
-            cachedDefault = true;
-        }
-    }
-
-    Extensions extensionFlags = currentContextExtensions();
-    if (currentCtx) {
+        extensionFlags = qtDefaultExtensions()->extensions;
+    } else {
+        extensionFlags = currentContextExtensions();
         currentCtx->d_func()->extension_flags_cached = true;
         currentCtx->d_func()->extension_flags = extensionFlags;
-    } else {
-        defaultExtensions = extensionFlags;
     }
-
-    if (tmpContext)
-        delete tmpContext;
-
     return extensionFlags;
 }
 
diff --git a/src/opengl/qgl_p.h b/src/opengl/qgl_p.h
index f66031a..45f8f30 100644
--- a/src/opengl/qgl_p.h
+++ b/src/opengl/qgl_p.h
@@ -278,8 +278,6 @@ public:
     Q_DECLARE_FLAGS(Extensions, Extension)
 
     static Extensions glExtensions();
-
-private:
     static Extensions currentContextExtensions();
 };
 
-- 
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