Bug 630201. Don't use DirectWrite for pre-RTM versions of Windows 7. r=bas, a=joedrew

gfx/thebes/gfxWindowsPlatform.cpp

@@ -408,6 +408,29 @@ gfxWindowsPlatform::VerifyD2DDevice(PRBool aAttemptForce)
 #endif
 }
 
+// bug 630201 - older pre-RTM versions of Direct2D/DirectWrite cause odd
+// crashers so blacklist them altogether
+
+#ifdef CAIRO_HAS_DWRITE_FONT
+#define WINDOWS7_RTM_BUILD 7600
+
+static PRBool
+AllowDirectWrite()
+{
+    PRInt32 winVers, buildNum;
+
+    winVers = gfxWindowsPlatform::WindowsOSVersion(&buildNum);
+    if (winVers == gfxWindowsPlatform::kWindows7 &&
+        buildNum < WINDOWS7_RTM_BUILD)
+    {
+        // don't use Direct2D/DirectWrite on older versions of Windows 7
+        return PR_FALSE;
+    }
+
+    return PR_TRUE;
+}
+#endif
+
 gfxPlatformFontList*
 gfxWindowsPlatform::CreatePlatformFontList()
 {
@@ -417,7 +440,7 @@ gfxWindowsPlatform::CreatePlatformFontList()
     pfl = new gfxFT2FontList();
 #else
 #ifdef CAIRO_HAS_DWRITE_FONT
-    if (GetDWriteFactory()) {
+    if (AllowDirectWrite() && GetDWriteFactory()) {
         pfl = new gfxDWriteFontList();
         if (NS_SUCCEEDED(pfl->InitFontList())) {
             return pfl;
@@ -677,9 +700,10 @@ gfxWindowsPlatform::UseClearTypeAlways()
 }
 
 PRInt32
-gfxWindowsPlatform::WindowsOSVersion()
+gfxWindowsPlatform::WindowsOSVersion(PRInt32 *aBuildNum)
 {
     static PRInt32 winVersion = UNINITIALIZED_VALUE;
+    static PRInt32 buildNum = UNINITIALIZED_VALUE;
 
     OSVERSIONINFO vinfo;
 
@@ -687,10 +711,17 @@ gfxWindowsPlatform::WindowsOSVersion()
         vinfo.dwOSVersionInfoSize = sizeof (vinfo);
         if (!GetVersionEx(&vinfo)) {
             winVersion = kWindowsUnknown;
+            buildNum = 0;
         } else {
             winVersion = PRInt32(vinfo.dwMajorVersion << 16) + vinfo.dwMinorVersion;
+            buildNum = PRInt32(vinfo.dwBuildNumber);
         }
     }
+
+    if (aBuildNum) {
+        *aBuildNum = buildNum;
+    }
+
     return winVersion;
 }
 

gfx/thebes/gfxWindowsPlatform.h

@@ -232,7 +232,7 @@ public:
         kWindows7 = 0x60001
     };
 
-    static PRInt32 WindowsOSVersion();
+    static PRInt32 WindowsOSVersion(PRInt32 *aBuildNum = nsnull);
 
     static void GetDLLVersion(const PRUnichar *aDLLPath, nsAString& aVersion);