Introduce isWindowsVistaOrGreater() as replacement of windowsVersion()

Source/platform/win/SystemInfo.cpp

Index: Source/platform/win/SystemInfo.cpp
diff --git a/Source/platform/win/SystemInfo.cpp b/Source/platform/win/SystemInfo.cpp
index 553f27e076591ccc24b19447836c0bb62848f456..b14bf83eb3f1ed92dfe92f48ac4b661ab6e6d008 100644
--- a/Source/platform/win/SystemInfo.cpp
+++ b/Source/platform/win/SystemInfo.cpp
@@ -26,54 +26,44 @@
 #include "config.h"
 #include "platform/win/SystemInfo.h"
 
+#if _WIN32_WINNT_WINBLUE
+#include <versionhelpers.h>
+#endif
+
 #include <windows.h>
 
 namespace WebCore {
 
-WindowsVersion windowsVersion(int* major, int* minor)
+#ifndef _WIN32_WINNT_WINBLUE
+// Taken from VersionHelpers.h in Windows SDK 8.1+.

[tkent, 2013/10/27 21:22:28]

Does the Windows SDK license allow to copy/redistribute the code?

[yosin_UTC9, 2013/10/28 04:30:59]

Not sure. So, I take yukawa@'s code.

+static bool IsWindowsVersionOrGreater(WORD majorVersion, WORD minorVersion, WORD servicePackMajor)
+{
+    const DWORDLONG mask1 = ::VerSetConditionMask(0, VER_MAJORVERSION, VER_GREATER_EQUAL);
+    const DWORDLONG mask2 = ::VerSetConditionMask(mask1, VER_MINORVERSION, VER_GREATER_EQUAL);
+    const DWORDLONG mask3 = ::VerSetConditionMask(mask2, VER_SERVICEPACKMAJOR, VER_GREATER_EQUAL);
+    OSVERSIONINFOEXW osvi = { sizeof(osvi), 0, 0, 0, 0, {0}, 0, 0 };
+    osvi.dwMajorVersion = majorVersion;
+    osvi.dwMinorVersion = minorVersion;
+    osvi.wServicePackMajor = servicePackMajor;
+    return ::VerifyVersionInfoW(&osvi, VER_MAJORVERSION | VER_MINORVERSION | VER_SERVICEPACKMAJOR, mask3);
+}
+
+static bool IsWindowsVistaOrGreater()
+{
+    return IsWindowsVersionOrGreater(HIBYTE(_WIN32_WINNT_VISTA), LOBYTE(_WIN32_WINNT_VISTA), 0);
+}
+#endif
+
+bool isWindowsVistaOrGreater()
 {
     static bool initialized = false;
-    static WindowsVersion version;
-    static int majorVersion, minorVersion;
+    static bool cachedIsWindowsVistaOrGreater;
 
     if (!initialized) {
         initialized = true;
-        OSVERSIONINFOEX versionInfo;
-        ZeroMemory(&versionInfo, sizeof(versionInfo));
-        versionInfo.dwOSVersionInfoSize = sizeof(versionInfo);
-        GetVersionEx(reinterpret_cast<OSVERSIONINFO*>(&versionInfo));
-        majorVersion = versionInfo.dwMajorVersion;
-        minorVersion = versionInfo.dwMinorVersion;
-
-        if (versionInfo.dwPlatformId == VER_PLATFORM_WIN32s) {
-            version = Windows3_1;
-        } else if (versionInfo.dwPlatformId == VER_PLATFORM_WIN32_WINDOWS) {
-            if (!minorVersion)
-                version = Windows95;
-            else
-                version = (minorVersion == 10) ? Windows98 : WindowsME;
-        } else {
-            if (majorVersion == 5) {
-                if (!minorVersion)
-                    version = Windows2000;
-                else
-                    version = (minorVersion == 1) ? WindowsXP : WindowsServer2003;
-            } else if (majorVersion >= 6) {
-                if (versionInfo.wProductType == VER_NT_WORKSTATION)
-                    version = (majorVersion == 6 && !minorVersion) ? WindowsVista : Windows7;
-                else
-                    version = WindowsServer2008;
-            } else {
-                version = (majorVersion == 4) ? WindowsNT4 : WindowsNT3;
-            }
-        }
+        cachedIsWindowsVistaOrGreater = IsWindowsVistaOrGreater();

[yukawa, 2013/10/28 02:21:19]

IsWindowsVersionOrGreater is just a helper wrapper of VerifyVersionInfo API. 
Let's use VerifyVersionInfo API as usual.

OSVERSIONINFOEXW osvi = {};
osvi.dwOSVersionInfoSize = sizeof(osvi);
osvi.dwMajorVersion = 6;  // Vista == Windows 6.0
osvi.dwMinorVersion = 0;  // Vista == Windows 6.0  
DWORDLONG conditoin = 0;
VER_SET_CONDITION(conditoin, VER_MAJORVERSION, VER_GREATER_EQUAL);
VER_SET_CONDITION(conditoin, VER_MINORVERSION, VER_GREATER_EQUAL);
cachedIsWindowsVistaOrGreater = !!::VerifyVersionInfoW(&osvi, VER_MAJORVERSION |
VER_MINORVERSION, conditoin);

(This code is surely written by me and can be licensed as a part of Blink)

[yosin_UTC9, 2013/10/28 04:30:59]

Thanks! I take yours.

     }
-
-    if (major)
-        *major = majorVersion;
-    if (minor)
-        *minor = minorVersion;
-    return version;
+    return cachedIsWindowsVistaOrGreater;
 }
 
 } // namespace WebCore