From 02b79d0d640c718358cf953f9a1d15ea35c83429 Mon Sep 17 00:00:00 2001
From: "Brian R. Bondy" <netzen@gmail.com>
Date: Fri, 22 Mar 2013 15:34:36 -0400
Subject: [PATCH] Bug 844954 - Add LoadLibrary RAII helper and System32
 LoadLirary helper for use anywhere. r=jimm

---
 xpcom/base/nsWindowsHelpers.h | 80 ++++++++++++++++++++++++++++-------
 1 file changed, 64 insertions(+), 16 deletions(-)

diff --git a/xpcom/base/nsWindowsHelpers.h b/xpcom/base/nsWindowsHelpers.h
index 4a75ea9e5e7e..331a58477b97 100644
--- a/xpcom/base/nsWindowsHelpers.h
+++ b/xpcom/base/nsWindowsHelpers.h
@@ -14,13 +14,13 @@ class nsAutoRefTraits<HKEY>
 {
 public:
   typedef HKEY RawRef;
-  static HKEY Void() 
-  { 
-    return NULL; 
+  static HKEY Void()
+  {
+    return NULL;
   }
 
-  static void Release(RawRef aFD) 
-  { 
+  static void Release(RawRef aFD)
+  {
     if (aFD != Void()) {
       RegCloseKey(aFD);
     }
@@ -32,13 +32,13 @@ class nsAutoRefTraits<SC_HANDLE>
 {
 public:
   typedef SC_HANDLE RawRef;
-  static SC_HANDLE Void() 
-  { 
-    return NULL; 
+  static SC_HANDLE Void()
+  {
+    return NULL;
   }
 
-  static void Release(RawRef aFD) 
-  { 
+  static void Release(RawRef aFD)
+  {
     if (aFD != Void()) {
       CloseServiceHandle(aFD);
     }
@@ -51,26 +51,26 @@ class nsSimpleRef<HANDLE>
 protected:
   typedef HANDLE RawRef;
 
-  nsSimpleRef() : mRawRef(NULL) 
+  nsSimpleRef() : mRawRef(NULL)
   {
   }
 
-  nsSimpleRef(RawRef aRawRef) : mRawRef(aRawRef) 
+  nsSimpleRef(RawRef aRawRef) : mRawRef(aRawRef)
   {
   }
 
-  bool HaveResource() const 
+  bool HaveResource() const
   {
     return mRawRef != NULL && mRawRef != INVALID_HANDLE_VALUE;
   }
 
 public:
-  RawRef get() const 
+  RawRef get() const
   {
     return mRawRef;
   }
 
-  static void Release(RawRef aRawRef) 
+  static void Release(RawRef aRawRef)
   {
     if (aRawRef != NULL && aRawRef != INVALID_HANDLE_VALUE) {
       CloseHandle(aRawRef);
@@ -79,9 +79,29 @@ public:
   RawRef mRawRef;
 };
 
+
+template<>
+class nsAutoRefTraits<HMODULE>
+{
+public:
+  typedef HMODULE RawRef;
+  static RawRef Void()
+  {
+    return NULL;
+  }
+
+  static void Release(RawRef aFD)
+  {
+    if (aFD != Void()) {
+      FreeLibrary(aFD);
+    }
+  }
+};
+
 typedef nsAutoRef<HKEY> nsAutoRegKey;
 typedef nsAutoRef<SC_HANDLE> nsAutoServiceHandle;
 typedef nsAutoRef<HANDLE> nsAutoHandle;
+typedef nsAutoRef<HMODULE> nsModuleHandle;
 
 namespace
 {
@@ -110,7 +130,7 @@ namespace
     }
 
     typedef BOOL (WINAPI* IsImmersiveProcessFunc)(HANDLE process);
-    IsImmersiveProcessFunc IsImmersiveProcessPtr = 
+    IsImmersiveProcessFunc IsImmersiveProcessPtr =
       (IsImmersiveProcessFunc)GetProcAddress(user32DLL,
                                               "IsImmersiveProcess");
     FreeLibrary(user32DLL);
@@ -124,6 +144,34 @@ namespace
     alreadyChecked = true;
     return isMetro;
   }
+
+  HMODULE
+  LoadLibrarySystem32(LPCWSTR module)
+  {
+    WCHAR systemPath[MAX_PATH + 1] = { L'\0' };
+
+    // If GetSystemPath fails we accept that we'll load the DLLs from the
+    // normal search path.
+    GetSystemDirectoryW(systemPath, MAX_PATH + 1);
+    size_t systemDirLen = wcslen(systemPath);
+
+    // Make the system directory path terminate with a slash
+    if (systemDirLen && systemPath[systemDirLen - 1] != L'\\') {
+      systemPath[systemDirLen] = L'\\';
+      ++systemDirLen;
+      // No need to re-NULL terminate
+    }
+
+    size_t fileLen = wcslen(module);
+    wcsncpy(systemPath + systemDirLen, module,
+            MAX_PATH - systemDirLen);
+    if (systemDirLen + fileLen <= MAX_PATH) {
+      systemPath[systemDirLen + fileLen] = L'\0';
+    } else {
+      systemPath[MAX_PATH] = L'\0';
+    }
+    return LoadLibraryW(systemPath);
+  }
 }
 
 #endif