Implemented reasonable table column autosizing on Windows.

redo/table_windows.c

@@ -20,6 +20,21 @@ static LRESULT CALLBACK tableSubProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM
 			return 0;
 		}
 		return (*fv_DefSubclassProc)(hwnd, uMsg, wParam, lParam);
+	/* the autosize behavior is simple: always autosize until the user manually sizes, then never autosize again (this is my best guess as to how GTK+ behaves) */
+	case WM_NOTIFY:		/* from the contained header control */
+		if (nmhdr->code == HDN_BEGINTRACK)
+			tableStopColumnAutosize((void *) data);
+		return (*fv_DefSubclassProc)(hwnd, uMsg, wParam, lParam);
+	case WM_SIZE:
+		if (tableAutosizeColumns((void *) data)) {
+			int i, nColumns;
+
+			nColumns = tableColumnCount((void *) data);
+			for (i = 0; i < nColumns; i++)
+				if (SendMessageW(hwnd, LVM_SETCOLUMNWIDTH, (WPARAM) i, (LPARAM) LVSCW_AUTOSIZE_USEHEADER) == FALSE)
+					xpanic("error resizing columns of results list view", GetLastError());
+		}
+		return (*fv_DefSubclassProc)(hwnd, uMsg, wParam, lParam);
 	case WM_NCDESTROY:
 		if ((*fv_RemoveWindowSubclass)(hwnd, tableSubProc, id) == FALSE)
 			xpanic("error removing Table subclass (which was for its own event handler)", GetLastError());

redo/table_windows.go

@@ -14,6 +14,8 @@ import "C"
 type table struct {
 	*tablebase
 	_hwnd		C.HWND
+	noautosize	bool
+	colcount		C.int
 }
 
 func finishNewTable(b *tablebase, ty reflect.Type) Table {
@@ -30,6 +32,7 @@ func finishNewTable(b *tablebase, ty reflect.Type) Table {
 	for i := 0; i < ty.NumField(); i++ {
 		C.tableAppendColumn(t._hwnd, C.int(i), toUTF16(ty.Field(i).Name))
 	}
+	t.colcount = C.int(ty.NumField())
 	return t
 }
 
@@ -53,6 +56,27 @@ func tableGetCellText(data unsafe.Pointer, row C.int, col C.int, str *C.LPWSTR)
 	*str = toUTF16(s)
 }
 
+//export tableStopColumnAutosize
+func tableStopColumnAutosize(data unsafe.Pointer) {
+	t := (*table)(data)
+	t.noautosize = true
+}
+
+//export tableAutosizeColumns
+func tableAutosizeColumns(data unsafe.Pointer) C.BOOL {
+	t := (*table)(data)
+	if t.noautosize {
+		return C.FALSE
+	}
+	return C.TRUE
+}
+
+//export tableColumnCount
+func tableColumnCount(data unsafe.Pointer) C.int {
+	t := (*table)(data)
+	return t.colcount
+}
+
 func (t *table) hwnd() C.HWND {
 	return t._hwnd
 }