Refactored win32 broadcast message handling to avoid clashes with MS Word

modules/juce_events/native/juce_win32_Messaging.cpp

@@ -30,15 +30,15 @@ CheckEventBlockedByModalComps isEventBlockedByModalComps = nullptr;
 //==============================================================================
 namespace WindowsMessageHelpers
 {
-    const unsigned int specialId   = WM_APP + 0x4400;
-    const unsigned int broadcastId = WM_APP + 0x4403;
+    const unsigned int customMessageID = WM_USER + 123;
+    const unsigned int broadcastMessageMagicNumber = 0xc403;
 
     const TCHAR messageWindowName[] = _T("JUCEWindow");
     ScopedPointer<HiddenMessageWindow> messageWindow;
 
     void dispatchMessageFromLParam (LPARAM lParam)
     {
-        if (MessageManager::MessageBase* const message = reinterpret_cast<MessageManager::MessageBase*> (lParam))
+        if (MessageManager::MessageBase* message = reinterpret_cast<MessageManager::MessageBase*> (lParam))
         {
             JUCE_TRY
             {
@@ -50,12 +50,44 @@ namespace WindowsMessageHelpers
         }
     }
 
+    BOOL CALLBACK broadcastEnumWindowProc (HWND hwnd, LPARAM lParam)
+    {
+        if (hwnd != juce_messageWindowHandle)
+        {
+            TCHAR windowName[64] = { 0 }; // no need to read longer strings than this
+            GetWindowText (hwnd, windowName, 63);
+
+            if (String (windowName) == messageWindowName)
+                reinterpret_cast<Array<HWND>*> (lParam)->add (hwnd);
+        }
+
+        return TRUE;
+    }
+
+    void handleBroadcastMessage (const COPYDATASTRUCT* const data)
+    {
+        if (data != nullptr && data->dwData == broadcastMessageMagicNumber)
+        {
+            struct BroadcastMessage  : public CallbackMessage
+            {
+                BroadcastMessage (CharPointer_UTF32 text, size_t length) : message (text, length) {}
+                void messageCallback() override { MessageManager::getInstance()->deliverBroadcastMessage (message); }
+
+                String message;
+            };
+
+            (new BroadcastMessage (CharPointer_UTF32 ((const CharPointer_UTF32::CharType*) data->lpData),
+                                   data->cbData / sizeof (CharPointer_UTF32::CharType)))
+                ->post();
+        }
+    }
+
     //==============================================================================
     LRESULT CALLBACK messageWndProc (HWND h, const UINT message, const WPARAM wParam, const LPARAM lParam) noexcept
     {
         if (h == juce_messageWindowHandle)
         {
-            if (message == specialId)
+            if (message == customMessageID)
             {
                 // (These are trapped early in our dispatch loop, but must also be checked
                 // here in case some 3rd-party code is running the dispatch loop).
@@ -63,43 +95,15 @@ namespace WindowsMessageHelpers
                 return 0;
             }
 
-            if (message == broadcastId)
-            {
-                if (String* const m = reinterpret_cast<String*> (lParam))
-                {
-                    const ScopedPointer<String> messageString (m);
-                    MessageManager::getInstance()->deliverBroadcastMessage (*m);
-                }
-
-                return 0;
-            }
-
             if (message == WM_COPYDATA)
             {
-                if (const COPYDATASTRUCT* const data = reinterpret_cast<const COPYDATASTRUCT*> (lParam))
-                {
-                    if (data->dwData == broadcastId)
-                    {
-                        const String messageString (CharPointer_UTF32 ((const CharPointer_UTF32::CharType*) data->lpData),
-                                                    data->cbData / sizeof (CharPointer_UTF32::CharType));
-
-                        PostMessage (juce_messageWindowHandle, broadcastId, 0, (LPARAM) new String (messageString));
-                        return 0;
-                    }
-                }
+                handleBroadcastMessage (reinterpret_cast<const COPYDATASTRUCT*> (lParam));
+                return 0;
             }
         }
 
         return DefWindowProc (h, message, wParam, lParam);
     }
-
-    BOOL CALLBACK broadcastEnumWindowProc (HWND hwnd, LPARAM lParam)
-    {
-        if (hwnd != juce_messageWindowHandle)
-            reinterpret_cast<Array<HWND>*> (lParam)->add (hwnd);
-
-        return TRUE;
-    }
 }
 
 //==============================================================================
@@ -113,7 +117,7 @@ bool MessageManager::dispatchNextMessageOnSystemQueue (const bool returnIfNoPend
 
     if (GetMessage (&m, (HWND) 0, 0, 0) >= 0)
     {
-        if (m.message == specialId && m.hwnd == juce_messageWindowHandle)
+        if (m.message == customMessageID && m.hwnd == juce_messageWindowHandle)
         {
             dispatchMessageFromLParam (m.lParam);
         }
@@ -146,36 +150,28 @@ bool MessageManager::dispatchNextMessageOnSystemQueue (const bool returnIfNoPend
 bool MessageManager::postMessageToSystemQueue (MessageManager::MessageBase* const message)
 {
     message->incReferenceCount();
-    return PostMessage (juce_messageWindowHandle, WindowsMessageHelpers::specialId, 0, (LPARAM) message) != 0;
+    return PostMessage (juce_messageWindowHandle, WindowsMessageHelpers::customMessageID, 0, (LPARAM) message) != 0;
 }
 
 void MessageManager::broadcastMessage (const String& value)
 {
-    Array<HWND> windows;
-    EnumWindows (&WindowsMessageHelpers::broadcastEnumWindowProc, (LPARAM) &windows);
-
     const String localCopy (value);
 
-    COPYDATASTRUCT data;
-    data.dwData = WindowsMessageHelpers::broadcastId;
-    data.cbData = (localCopy.length() + 1) * sizeof (CharPointer_UTF32::CharType);
-    data.lpData = (void*) localCopy.toUTF32().getAddress();
+    Array<HWND> windows;
+    EnumWindows (&WindowsMessageHelpers::broadcastEnumWindowProc, (LPARAM) &windows);
 
     for (int i = windows.size(); --i >= 0;)
     {
-        HWND hwnd = windows.getUnchecked(i);
-
-        TCHAR windowName[64] = { 0 }; // no need to read longer strings than this
-        GetWindowText (hwnd, windowName, 63);
-
-        if (String (windowName) == WindowsMessageHelpers::messageWindowName)
-        {
-            DWORD_PTR result;
-            SendMessageTimeout (hwnd, WM_COPYDATA,
-                                (WPARAM) juce_messageWindowHandle,
-                                (LPARAM) &data,
-                                SMTO_BLOCK | SMTO_ABORTIFHUNG, 8000, &result);
-        }
+        COPYDATASTRUCT data;
+        data.dwData = WindowsMessageHelpers::broadcastMessageMagicNumber;
+        data.cbData = (localCopy.length() + 1) * sizeof (CharPointer_UTF32::CharType);
+        data.lpData = (void*) localCopy.toUTF32().getAddress();
+
+        DWORD_PTR result;
+        SendMessageTimeout (windows.getUnchecked(i), WM_COPYDATA,
+                            (WPARAM) juce_messageWindowHandle,
+                            (LPARAM) &data,
+                            SMTO_BLOCK | SMTO_ABORTIFHUNG, 8000, &result);
     }
 }