diff -r 000000000000 -r 6474c204b198 mfbt/WindowsVersion.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mfbt/WindowsVersion.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,125 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_WindowsVersion_h
+#define mozilla_WindowsVersion_h
+
+#include "mozilla/Attributes.h"
+#include <stdint.h>
+#include <windows.h>
+
+namespace mozilla
+{
+  inline bool
+  IsWindowsVersionOrLater(uint32_t aVersion)
+  {
+    static uint32_t minVersion = 0;
+    static uint32_t maxVersion = UINT32_MAX;
+
+    if (minVersion >= aVersion) {
+      return true;
+    }
+
+    if (aVersion >= maxVersion) {
+      return false;
+    }
+
+    OSVERSIONINFOEX info;
+    ZeroMemory(&info, sizeof(OSVERSIONINFOEX));
+    info.dwOSVersionInfoSize = sizeof(OSVERSIONINFOEX);
+    info.dwMajorVersion = aVersion >> 24;
+    info.dwMinorVersion = (aVersion >> 16) & 0xFF;
+    info.wServicePackMajor = (aVersion >> 8) & 0xFF;
+    info.wServicePackMinor = aVersion & 0xFF;
+
+    DWORDLONG conditionMask = 0;
+    VER_SET_CONDITION(conditionMask, VER_MAJORVERSION, VER_GREATER_EQUAL);
+    VER_SET_CONDITION(conditionMask, VER_MINORVERSION, VER_GREATER_EQUAL);
+    VER_SET_CONDITION(conditionMask, VER_SERVICEPACKMAJOR, VER_GREATER_EQUAL);
+    VER_SET_CONDITION(conditionMask, VER_SERVICEPACKMINOR, VER_GREATER_EQUAL);
+
+    if (VerifyVersionInfo(&info,
+                          VER_MAJORVERSION | VER_MINORVERSION |
+                          VER_SERVICEPACKMAJOR | VER_SERVICEPACKMINOR,
+                          conditionMask)) {
+      minVersion = aVersion;
+      return true;
+    }
+
+    maxVersion = aVersion;
+    return false;
+  }
+
+  inline bool
+  IsWindowsBuildOrLater(uint32_t aBuild)
+  {
+    static uint32_t minBuild = 0;
+    static uint32_t maxBuild = UINT32_MAX;
+
+    if (minBuild >= aBuild) {
+      return true;
+    }
+
+    if (aBuild >= maxBuild) {
+      return false;
+    }
+
+    OSVERSIONINFOEX info;
+    ZeroMemory(&info, sizeof(OSVERSIONINFOEX));
+    info.dwOSVersionInfoSize = sizeof(OSVERSIONINFOEX);
+    info.dwBuildNumber = aBuild;
+
+    DWORDLONG conditionMask = 0;
+    VER_SET_CONDITION(conditionMask, VER_BUILDNUMBER, VER_GREATER_EQUAL);
+
+    if (VerifyVersionInfo(&info, VER_BUILDNUMBER, conditionMask)) {
+      minBuild = aBuild;
+      return true;
+    }
+
+    maxBuild = aBuild;
+    return false;
+  }
+
+  MOZ_ALWAYS_INLINE bool
+  IsXPSP3OrLater()
+  { return IsWindowsVersionOrLater(0x05010300ul); }
+
+  MOZ_ALWAYS_INLINE bool
+  IsWin2003OrLater()
+  { return IsWindowsVersionOrLater(0x05020000ul); }
+
+  MOZ_ALWAYS_INLINE bool
+  IsWin2003SP2OrLater()
+  { return IsWindowsVersionOrLater(0x05020200ul); }
+
+  MOZ_ALWAYS_INLINE bool
+  IsVistaOrLater()
+  { return IsWindowsVersionOrLater(0x06000000ul); }
+
+  MOZ_ALWAYS_INLINE bool
+  IsVistaSP1OrLater()
+  { return IsWindowsVersionOrLater(0x06000100ul); }
+
+  MOZ_ALWAYS_INLINE bool
+  IsWin7OrLater()
+  { return IsWindowsVersionOrLater(0x06010000ul); }
+
+  MOZ_ALWAYS_INLINE bool
+  IsWin7SP1OrLater()
+  { return IsWindowsVersionOrLater(0x06010100ul); }
+
+  MOZ_ALWAYS_INLINE bool
+  IsWin8OrLater()
+  { return IsWindowsVersionOrLater(0x06020000ul); }
+
+  MOZ_ALWAYS_INLINE bool
+  IsNotWin7PreRTM()
+  {
+    return IsWin7SP1OrLater() || !IsWin7OrLater() ||
+           IsWindowsBuildOrLater(7600);
+  }
+}
+
+#endif /* mozilla_WindowsVersion_h */