Split layout and Window on Windows to use two separate window classes. This is the first half of the two-part migration of the Windows backend to use container.

redo/container_windows.c

@@ -0,0 +1,84 @@
+/* 17 july 2014 */
+
+#include "winapi_windows.h"
+#include "_cgo_export.h"
+
+/*
+This could all just be part of Window, but doing so just makes things complex.
+In this case, I chose to waste a window handle rather than keep things super complex.
+If this is seriously an issue in the future, I can roll it back.
+*/
+
+#define containerclass L"gouicontainer"
+
+static LRESULT CALLBACK containerWndProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
+{
+	void *data;
+	RECT r;
+
+	data = (void *) GetWindowLongPtrW(hwnd, GWLP_USERDATA);
+	if (data == NULL) {
+		/* the lpParam is available during WM_NCCREATE and WM_CREATE */
+		if (uMsg == WM_NCCREATE) {
+			storelpParam(hwnd, lParam);
+			data = (void *) GetWindowLongPtrW(hwnd, GWLP_USERDATA);
+			storeContainerHWND(data, hwnd);
+		}
+		/* act as if we're not ready yet, even during WM_NCCREATE (nothing important to the switch statement below happens here anyway) */
+		return DefWindowProcW(hwnd, uMsg, wParam, lParam);
+	}
+
+	switch (uMsg) {
+	case WM_COMMAND:
+		return forwardCommand(hwnd, uMsg, wParam, lParam);
+	case WM_NOTIFY:
+		return forwardNotify(hwnd, uMsg, wParam, lParam);
+	case WM_SIZE:
+		if (GetClientRect(hwnd, &r) == 0)
+			xpanic("error getting client rect for Window in WM_SIZE", GetLastError());
+		containerResize(data, &r);
+		return 0;
+	default:
+		return DefWindowProcW(hwnd, uMsg, wParam, lParam);
+	}
+	xmissedmsg("container", "containerWndProc()", uMsg);
+	return 0;		/* unreached */
+}
+
+DWORD makeContainerWindowClass(char **errmsg)
+{
+	WNDCLASSW wc;
+
+	ZeroMemory(&wc, sizeof (WNDCLASSW));
+	wc.lpfnWndProc = containerWndProc;
+	wc.hInstance = hInstance;
+	wc.hIcon = hDefaultIcon;
+	wc.hCursor = hArrowCursor;
+	wc.hbrBackground = (HBRUSH) GetStockObject(HOLLOW_BRUSH);
+	if (wc.hbrBackground == NULL) {
+		*errmsg = "error getting hollow brush for container window class";
+		return GetLastError();
+	}
+	wc.lpszClassName = containerclass;
+	if (RegisterClassW(&wc) == 0) {
+		*errmsg = "error registering container window class";
+		return GetLastError();
+	}
+	return 0;
+}
+
+HWND newContainer(void *data)
+{
+	HWND hwnd;
+
+	hwnd = CreateWindowExW(
+		0,
+		containerclass, L"",
+		WS_CHILD | WS_VISIBLE,
+		CW_USEDEFAULT, CW_USEDEFAULT,
+		100, 100,
+		msgwin, NULL, hInstance, data);
+	if (hwnd == NULL)
+		xpanic("container creation failed", GetLastError());
+	return hwnd;
+}

redo/layout_windows.go

@@ -20,15 +20,23 @@ type layout struct {
 	*sizer
 }
 
+func makeContainerWindowClass() error {
+	var errmsg *C.char
+
+	err := C.makeContainerWindowClass(&errmsg)
+	if err != 0 || errmsg != nil {
+		return fmt.Errorf("%s: %v", C.GoString(errmsg), syscall.Errno(err))
+	}
+	return nil
+}
+
 func newLayout(title string, width int, height int, child C.BOOL, control Control) *layout {
 	l := &layout{
-		// hwnd set in WM_CREATE handler
-		closing:		newEvent(),
 		sizer:		new(sizer),
 	}
-	hwnd := C.newWindow(toUTF16(title), C.int(width), C.int(height), child, unsafe.Pointer(l))
+	hwnd := C.newContainer(unsafe.Pointer(l))
 	if hwnd != l.hwnd {
-		panic(fmt.Errorf("inconsistency: hwnd returned by CreateWindowEx() (%p) and hwnd stored in window/layout (%p) differ", hwnd, l.hwnd))
+		panic(fmt.Errorf("inconsistency: hwnd returned by CreateWindowEx() (%p) and hwnd stored in container (%p) differ", hwnd, l.hwnd))
 	}
 	l.child = control
 	l.child.setParent(&controlParent{l.hwnd})
@@ -39,24 +47,15 @@ func (l *layout) setParent(p *controlParent) {
 	C.controlSetParent(l.hwnd, p.hwnd)
 }
 
-//export storeWindowHWND
-func storeWindowHWND(data unsafe.Pointer, hwnd C.HWND) {
+//export storeContainerHWND
+func storeContainerHWND(data unsafe.Pointer, hwnd C.HWND) {
 	l := (*layout)(data)
 	l.hwnd = hwnd
 }
 
-//export windowResize
-func windowResize(data unsafe.Pointer, r *C.RECT) {
+//export containerResize
+func containerResize(data unsafe.Pointer, r *C.RECT) {
 	l := (*layout)(data)
 	// the origin of the window's content area is always (0, 0), but let's use the values from the RECT just to be safe
 	l.resize(int(r.left), int(r.top), int(r.right - r.left), int(r.bottom - r.top))
 }
-
-//export windowClosing
-func windowClosing(data unsafe.Pointer) {
-	l := (*layout)(data)
-	close := l.closing.fire()
-	if close {
-		C.windowClose(l.hwnd)
-	}
-}

redo/uitask_windows.go

@@ -30,6 +30,9 @@ func uiinit() error {
 	if err := makeWindowWindowClass(); err != nil {
 		return fmt.Errorf("error creating Window window class: %v", err)
 	}
+	if err := makeContainerWindowClass(); err != nil {
+		return fmt.Errorf("error creating container window class: %v", err)
+	}
 	return nil
 }
 

redo/winapi_windows.h

@@ -74,7 +74,7 @@ extern LONG controlTextLength(HWND, LPWSTR);
 
 /* window_windows.c */
 extern DWORD makeWindowWindowClass(char **);
-extern HWND newWindow(LPWSTR, int, int, BOOL, void *);
+extern HWND newWindow(LPWSTR, int, int, void *);
 extern void windowClose(HWND);
 
 /* common_windows.c */
@@ -98,4 +98,8 @@ extern void tableAppendColumn(HWND, int, LPWSTR);
 extern void tableUpdate(HWND, int);
 extern void tableAddExtendedStyles(HWND, LPARAM);
 
+/* container_windows.c */
+extern DWORD makeContainerWindowClass(char **);
+extern HWND newContainer(void *);
+
 #endif

redo/window_windows.c

@@ -60,29 +60,20 @@ DWORD makeWindowWindowClass(char **errmsg)
 	return 0;
 }
 
-HWND newWindow(LPWSTR title, int width, int height, BOOL child, void *data)
+HWND newWindow(LPWSTR title, int width, int height, void *data)
 {
 	HWND hwnd;
-	DWORD style;
-	HWND parent;
 
-	style = WS_OVERLAPPEDWINDOW;
-	parent = NULL;
-	if (child) {
-		style = WS_CHILD | WS_VISIBLE;
-		parent = msgwin;
-	}
 	hwnd = CreateWindowExW(
 		0,
 		windowclass, title,
-		style,
+		WS_OVERLAPPEDWINDOW,
 		CW_USEDEFAULT, CW_USEDEFAULT,
 		width, height,
-		parent, NULL, hInstance, data);
+		NULL, NULL, hInstance, data);
 	if (hwnd == NULL)
 		xpanic("Window creation failed", GetLastError());
-	if (!child)
-		calculateBaseUnits(hwnd);
+	calculateBaseUnits(hwnd);
 	return hwnd;
 }
 

redo/window_windows.go

@@ -11,8 +11,12 @@ import (
 import "C"
 
 type window struct {
-	*layout
+	hwnd		C.HWND
 	shownbefore	bool
+
+	closing		*event
+
+	*layout
 }
 
 func makeWindowWindowClass() error {
@@ -27,13 +31,20 @@ func makeWindowWindowClass() error {
 
 func newWindow(title string, width int, height int, control Control) *window {
 	w := &window{
-		layout:	newLayout(title, width, height, C.FALSE, control),
+		// hwnd set in WM_CREATE handler
+		closing:		newEvent(),
+		layout:		newLayout(control),
+	}
+	hwnd := C.newWindow(toUTF16(title), C.int(width), C.int(height), unsafe.Pointer(w))
+	if hwnd != l.hwnd {
+		panic(fmt.Errorf("inconsistency: hwnd returned by CreateWindowEx() (%p) and hwnd stored in Window (%p) differ", hwnd, w.hwnd))
 	}
 	// TODO keep?
 	hresult := C.EnableThemeDialogTexture(w.hwnd, C.ETDT_ENABLE | C.ETDT_USETABTEXTURE)
 	if hresult != C.S_OK {
 		panic(fmt.Errorf("error setting tab background texture on Window; HRESULT: 0x%X", hresult))
 	}
+	w.layout.setParent(&controlParent{w.hwnd})
 	return w
 }
 
@@ -66,3 +77,26 @@ func (w *window) Close() {
 func (w *window) OnClosing(e func() bool) {
 	w.closing.setbool(e)
 }
+
+//export storeWindowHWND
+func storeWindowHWND(data unsafe.Pointer, hwnd C.HWND) {
+	w := (*wiindow)(data)
+	w.hwnd = hwnd
+}
+
+//export windowResize
+func windowResize(data unsafe.Pointer, r *C.RECT) {
+	w := (*window)(data)
+	// the origin of the window's content area is always (0, 0), but let's use the values from the RECT just to be safe
+	// TODO
+	C.moveWindow(w.layout.hwnd, int(r.left), int(r.top), int(r.right - r.left), int(r.bottom - r.top))
+}
+
+//export windowClosing
+func windowClosing(data unsafe.Pointer) {
+	l := (*layout)(data)
+	close := l.closing.fire()
+	if close {
+		C.windowClose(l.hwnd)
+	}
+}