More Windows window class logic simplification. This will be needed for read-only TextFields, next.

1 files changed, 34 insertions, 4 deletions

diff --git a/common_windows.c b/common_windows.c
index 9e67a0c..e0142c8 100644
--- a/common_windows.c
+++ b/common_windows.c
@@ -45,6 +45,39 @@ void *getWindowData(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam, LRESULT
 	return data;
 }
 
+// this is a helper function that takes the logic of determining window classes and puts it all in one place
+// there are a number of places where we need to know what window class an arbitrary handle has
+// theoretically we could use the class atom to avoid a _wcsicmp()
+// however, raymond chen advises against this - http://blogs.msdn.com/b/oldnewthing/archive/2004/10/11/240744.aspx (and we're not in control of the Tab class, before you say anything)
+// usage: windowClassOf(hwnd, L"class 1", L"class 2", ..., NULL)
+int windowClassOf(HWND hwnd, ...)
+{
+// MSDN says 256 is the maximum length of a class name; add a few characters just to be safe (because it doesn't say whether this includes the terminating null character)
+#define maxClassName 260
+	WCHAR classname[maxClassName + 1];
+	va_list ap;
+	WCHAR *curname;
+	int i;
+
+	if (GetClassNameW(hwnd, classname, maxClassName) == 0)
+		xpanic("error getting name of window class in windowClassOf()", GetLastError());
+	va_start(ap, hwnd);
+	i = 0;
+	for (;;) {
+		curname = va_arg(ap, WCHAR *);
+		if (curname == NULL)
+			break;
+		if (_wcsicmp(classname, curname) == 0) {
+			va_end(ap);
+			return i;
+		}
+		i++;
+	}
+	// no match
+	va_end(ap);
+	return -1;
+}
+
 /*
 all container windows (including the message-only window, hence this is not in container_windows.c) have to call the sharedWndProc() to ensure messages go in the right place and control colors are handled properly
 */
@@ -100,7 +133,6 @@ void paintControlBackground(HWND hwnd, HDC dc)
 	HWND parent;
 	RECT r;
 	POINT p, pOrig;
-	WCHAR classname[maxClassName + 1] = L"";
 
 	parent = hwnd;
 	for (;;) {
@@ -110,10 +142,8 @@ void paintControlBackground(HWND hwnd, HDC dc)
 		// wine sends these messages early, yay...
 		if (parent == msgwin)
 			return;
-		if (GetClassNameW(parent, classname, maxClassName) == 0)
-			xpanic("error getting name of focused window class in paintControlBackground()", GetLastError());
 		// skip groupboxes; they're (supposed to be) transparent
-		if (_wcsicmp(classname, L"button") != 0)
+		if (windowClassOf(parent, L"button", NULL) != 0)
 			break;
 	}
 	if (GetWindowRect(hwnd, &r) == 0)