Add convenience functions for open + save dialogs.

core/sys/win32/comdlg32.odin

@@ -2,6 +2,7 @@
 package win32
 
 foreign import "system:comdlg32.lib"
+import "core:strings"
 
 OFN_Hook_Proc :: #type proc "stdcall" (hdlg: Hwnd, msg: u32, wparam: Wparam, lparam: Lparam) -> Uint_Ptr;
 
@@ -61,11 +62,82 @@ Open_File_Name_W :: struct {
 foreign comdlg32 {
 	@(link_name="GetOpenFileNameA") get_open_file_name_a :: proc(arg1: ^Open_File_Name_A) -> Bool ---
 	@(link_name="GetOpenFileNameW") get_open_file_name_w :: proc(arg1: ^Open_File_Name_W) -> Bool ---
-
+	@(link_name="GetSaveFileNameA") get_save_file_name_a :: proc(arg1: ^Open_File_Name_A) -> Bool ---
+	@(link_name="GetSaveFileNameW") get_save_file_name_w :: proc(arg1: ^Open_File_Name_W) -> Bool ---
 	@(link_name="CommDlgExtendedError") comm_dlg_extended_error :: proc() -> u32 ---
 }
 
-OFN_ALLOWMULTISELECT     :: 0x00000200;
+OPEN_TITLE :: "Select file to open";
+OPEN_FLAGS :: u32(OFN_PATHMUSTEXIST | OFN_FILEMUSTEXIST);
+OPEN_FLAGS_MULTI :: u32(OPEN_FLAGS | OFN_ALLOWMULTISELECT | OFN_EXPLORER);
+
+SAVE_TITLE :: "Select file to save";
+SAVE_FLAGS :: u32(OFN_OVERWRITEPROMPT | OFN_EXPLORER);
+SAVE_EXT   :: "txt";
+
+OpenSaveMode :: enum{
+	Open = 0,
+	Save = 1,
+}
+
+_open_file_dialog :: proc(title: string, dir: string, filters: []string, default_filter: u32, flags: u32, default_ext: string, mode: OpenSaveMode, allocator := context.temp_allocator) -> (path: string, ok: bool) {
+	ok = true;
+
+	file_buf := make([]u16, MAX_PATH_WIDE, allocator);
+
+	// Filters need to be passed as a pair of strings (title, filter)
+	filter_len := u32(len(filters));
+	if filter_len % 2 != 0 do return "", false;
+	default_filter = clamp(default_filter, 1, filter_len / 2);
+
+	filter   := strings.join(filters, "\u0000", context.temp_allocator);
+	filter    = strings.concatenate({filter, "\u0000"}, context.temp_allocator);
+	filter_w := utf8_to_wstring(filter, context.temp_allocator);
+
+	ofn := Open_File_Name_W{
+		struct_size = size_of(Open_File_Name_W),
+		file = Wstring(&file_buf[0]),
+		max_file = MAX_PATH_WIDE,
+		title = utf8_to_wstring(title, context.temp_allocator),
+		filter = filter_w,
+		initial_dir = utf8_to_wstring(dir, context.temp_allocator),
+		filter_index = u32(default_filter),
+		def_ext = utf8_to_wstring(default_ext, context.temp_allocator),
+		flags = u32(flags),
+	};
+
+	if mode == OpenSaveMode.Open {
+		ok = bool(get_open_file_name_w(&ofn));	
+	} else if mode == OpenSaveMode.Save {
+		ok = bool(get_save_file_name_w(&ofn));
+	} else do ok = false;
+	
+	if !ok {
+		delete(file_buf);
+		return "", false;
+	}
+
+	file_name := ucs2_to_utf8(file_buf[:], allocator);
+	path = strings.trim_right_null(file_name);
+	return;
+}
+
+select_file_to_open :: proc(title := OPEN_TITLE, dir := ".", filters := []string{"All Files", "*.*"}, default_filter := u32(1), flags := OPEN_FLAGS, allocator := context.temp_allocator) -> (path: string, ok: bool) {
+
+	path, ok = _open_file_dialog(title, dir, filters, default_filter, flags, "", OpenSaveMode.Open, allocator);
+	return;
+}
+
+select_file_to_save :: proc(title := SAVE_TITLE, dir := ".", filters := []string{"All Files", "*.*"}, default_filter := u32(1), flags := SAVE_FLAGS, default_ext := SAVE_EXT, allocator := context.temp_allocator) -> (path: string, ok: bool) {
+
+	path, ok = _open_file_dialog(title, dir, filters, default_filter, flags, default_ext, OpenSaveMode.Save, allocator);
+	return;
+}
+
+// TODO: Implement convenience function for select_file_to_open with ALLOW_MULTI_SELECT that takes 
+//       it output of the form "path\u0000\file1u\0000file2" and turns it into []string with the path + file pre-concatenated for you.
+
+OFN_ALLOWMULTISELECT     :: 0x00000200; // NOTE(Jeroen): Without OFN_EXPLORER it uses the Win3 dialog.
 OFN_CREATEPROMPT         :: 0x00002000;
 OFN_DONTADDTORECENT      :: 0x02000000;
 OFN_ENABLEHOOK           :: 0x00000020;
@@ -91,3 +163,18 @@ OFN_PATHMUSTEXIST        :: 0x00000800;
 OFN_READONLY             :: 0x00000001;
 OFN_SHAREAWARE           :: 0x00004000;
 OFN_SHOWHELP             :: 0x00000010;
+
+CDERR_DIALOGFAILURE      :: 0x0000FFFF;
+CDERR_GENERALCODES       :: 0x00000000;
+CDERR_STRUCTSIZE         :: 0x00000001;
+CDERR_INITIALIZATION     :: 0x00000002;
+CDERR_NOTEMPLATE         :: 0x00000003;
+CDERR_NOHINSTANCE        :: 0x00000004;
+CDERR_LOADSTRFAILURE     :: 0x00000005;
+CDERR_FINDRESFAILURE     :: 0x00000006;
+CDERR_LOADRESFAILURE     :: 0x00000007;
+CDERR_LOCKRESFAILURE     :: 0x00000008;
+CDERR_MEMALLOCFAILURE    :: 0x00000009;
+CDERR_MEMLOCKFAILURE     :: 0x0000000A;
+CDERR_NOHOOK             :: 0x0000000B;
+CDERR_REGISTERMSGFAIL    :: 0x0000000C;