Timeouts, cancellation (windows).

color_windows.go

@@ -46,15 +46,18 @@ func selectColor(options []Option) (color.Color, error) {
 	runtime.LockOSThread()
 	defer runtime.UnlockOSThread()
 
-	if opts.title != "" {
+	if opts.ctx != nil || opts.title != "" {
-		hook, err := hookDialogTitle(opts.title)
+		unhook, err := hookDialogTitle(opts.ctx, opts.title)
-		if hook == 0 {
+		if err != nil {
 			return nil, err
 		}
-		defer unhookWindowsHookEx.Call(hook)
+		defer unhook()
 	}
 
 	s, _, _ := chooseColor.Call(uintptr(unsafe.Pointer(&args)))
+	if opts.ctx != nil && opts.ctx.Err() != nil {
+		return nil, opts.ctx.Err()
+	}
 	if s == 0 {
 		return nil, commDlgError()
 	}

file_windows.go

@@ -46,7 +46,18 @@ func selectFile(options []Option) (string, error) {
 	runtime.LockOSThread()
 	defer runtime.UnlockOSThread()
 
+	if opts.ctx != nil {
+		unhook, err := hookDialog(opts.ctx, nil)
+		if err != nil {
+			return "", err
+		}
+		defer unhook()
+	}
+
 	s, _, _ := getOpenFileName.Call(uintptr(unsafe.Pointer(&args)))
+	if opts.ctx != nil && opts.ctx.Err() != nil {
+		return "", opts.ctx.Err()
+	}
 	if s == 0 {
 		return "", commDlgError()
 	}
@@ -82,7 +93,18 @@ func selectFileMutiple(options []Option) ([]string, error) {
 	runtime.LockOSThread()
 	defer runtime.UnlockOSThread()
 
+	if opts.ctx != nil {
+		unhook, err := hookDialog(opts.ctx, nil)
+		if err != nil {
+			return nil, err
+		}
+		defer unhook()
+	}
+
 	s, _, _ := getOpenFileName.Call(uintptr(unsafe.Pointer(&args)))
+	if opts.ctx != nil && opts.ctx.Err() != nil {
+		return nil, opts.ctx.Err()
+	}
 	if s == 0 {
 		return nil, commDlgError()
 	}
@@ -149,7 +171,18 @@ func selectFileSave(options []Option) (string, error) {
 	runtime.LockOSThread()
 	defer runtime.UnlockOSThread()
 
+	if opts.ctx != nil {
+		unhook, err := hookDialog(opts.ctx, nil)
+		if err != nil {
+			return "", err
+		}
+		defer unhook()
+	}
+
 	s, _, _ := getSaveFileName.Call(uintptr(unsafe.Pointer(&args)))
+	if opts.ctx != nil && opts.ctx.Err() != nil {
+		return "", opts.ctx.Err()
+	}
 	if s == 0 {
 		return "", commDlgError()
 	}

msg_windows.go

@@ -1,6 +1,7 @@
 package zenity
 
 import (
+	"context"
 	"runtime"
 	"syscall"
 	"unsafe"
@@ -41,21 +42,24 @@ func message(kind messageKind, text string, options []Option) (bool, error) {
 		}
 	}
 
-	if opts.okLabel != "" || opts.cancelLabel != "" || opts.extraButton != "" {
+	if opts.ctx != nil || opts.okLabel != "" || opts.cancelLabel != "" || opts.extraButton != "" {
 		runtime.LockOSThread()
 		defer runtime.UnlockOSThread()
 
-		hook, err := hookMessageLabels(kind, opts)
+		unhook, err := hookMessageLabels(kind, opts)
-		if hook == 0 {
+		if err != nil {
 			return false, err
 		}
-		defer unhookWindowsHookEx.Call(hook)
+		defer unhook()
 	}
 
 	s, _, err := messageBox.Call(0,
 		uintptr(unsafe.Pointer(syscall.StringToUTF16Ptr(text))),
 		uintptr(unsafe.Pointer(syscall.StringToUTF16Ptr(opts.title))), flags)
 
+	if opts.ctx != nil && opts.ctx.Err() != nil {
+		return false, opts.ctx.Err()
+	}
 	if s == 0 {
 		return false, err
 	}
@@ -68,17 +72,11 @@ func message(kind messageKind, text string, options []Option) (bool, error) {
 	return false, nil
 }
 
-func hookMessageLabels(kind messageKind, opts options) (hook uintptr, err error) {
+func hookMessageLabels(kind messageKind, opts options) (unhook context.CancelFunc, err error) {
-	tid, _, _ := getCurrentThreadId.Call()
+	return hookDialog(opts.ctx, func(wnd uintptr) {
-	hook, _, err = setWindowsHookEx.Call(12, // WH_CALLWNDPROCRET
+		enumChildWindows.Call(wnd,
-		syscall.NewCallback(func(code int, wparam uintptr, lparam *_CWPRETSTRUCT) uintptr {
-			if lparam.Message == 0x0110 { // WM_INITDIALOG
-				name := [7]uint16{}
-				getClassName.Call(lparam.Wnd, uintptr(unsafe.Pointer(&name)), uintptr(len(name)))
-				if syscall.UTF16ToString(name[:]) == "#32770" { // The class for a dialog box
-					enumChildWindows.Call(lparam.Wnd,
 			syscall.NewCallback(func(wnd, lparam uintptr) uintptr {
-							name := [7]uint16{}
+				name := [8]uint16{}
 				getClassName.Call(wnd, uintptr(unsafe.Pointer(&name)), uintptr(len(name)))
 				if syscall.UTF16ToString(name[:]) == "Button" {
 					ctl, _, _ := getDlgCtrlID.Call(wnd)
@@ -104,10 +102,5 @@ func hookMessageLabels(kind messageKind, opts options) (hook uintptr, err error)
 				}
 				return 1
 			}), 0)
-				}
+	})
-			}
-			next, _, _ := callNextHookEx.Call(hook, uintptr(code), wparam, uintptr(unsafe.Pointer(lparam)))
-			return next
-		}), 0, tid)
-	return
 }

util_windows.go

@@ -1,7 +1,9 @@
 package zenity
 
 import (
+	"context"
 	"fmt"
+	"sync"
 	"syscall"
 	"unsafe"
 )
@@ -49,22 +51,73 @@ type _CWPRETSTRUCT struct {
 	Wnd     uintptr
 }
 
-func hookDialogTitle(title string) (hook uintptr, err error) {
+func hookDialog(ctx context.Context, initDialog func(wnd uintptr)) (unhook context.CancelFunc, err error) {
+	if ctx != nil && ctx.Err() != nil {
+		return nil, ctx.Err()
+	}
+
+	var mtx sync.Mutex
+	var hook, wnd uintptr
 	tid, _, _ := getCurrentThreadId.Call()
 	hook, _, err = setWindowsHookEx.Call(12, // WH_CALLWNDPROCRET
 		syscall.NewCallback(func(code int, wparam uintptr, lparam *_CWPRETSTRUCT) uintptr {
 			if lparam.Message == 0x0110 { // WM_INITDIALOG
-				name := [7]uint16{}
+				name := [8]uint16{}
 				getClassName.Call(lparam.Wnd, uintptr(unsafe.Pointer(&name)), uintptr(len(name)))
 				if syscall.UTF16ToString(name[:]) == "#32770" { // The class for a dialog box
-					ptr := syscall.StringToUTF16Ptr(title)
+					var close bool
-					setWindowText.Call(lparam.Wnd, uintptr(unsafe.Pointer(ptr)))
+
+					mtx.Lock()
+					if ctx != nil && ctx.Err() != nil {
+						close = true
+					} else {
+						wnd = lparam.Wnd
+					}
+					mtx.Unlock()
+
+					if close {
+						sendMessage.Call(lparam.Wnd, 0x0112 /* WM_SYSCOMMAND */, 0xf060 /* SC_CLOSE */, 0)
+					} else if initDialog != nil {
+						initDialog(lparam.Wnd)
+					}
 				}
 			}
 			next, _, _ := callNextHookEx.Call(hook, uintptr(code), wparam, uintptr(unsafe.Pointer(lparam)))
 			return next
 		}), 0, tid)
-	return
+
+	if hook == 0 {
+		return nil, err
+	}
+	if ctx == nil {
+		return func() { unhookWindowsHookEx.Call(hook) }, nil
+	}
+
+	wait := make(chan struct{})
+	go func() {
+		select {
+		case <-ctx.Done():
+			mtx.Lock()
+			w := wnd
+			mtx.Unlock()
+
+			if w != 0 {
+				sendMessage.Call(w, 0x0112 /* WM_SYSCOMMAND */, 0xf060 /* SC_CLOSE */, 0)
+			}
+		case <-wait:
+		}
+	}()
+	return func() {
+		unhookWindowsHookEx.Call(hook)
+		close(wait)
+	}, nil
+}
+
+func hookDialogTitle(ctx context.Context, title string) (unhook context.CancelFunc, err error) {
+	return hookDialog(ctx, func(wnd uintptr) {
+		ptr := syscall.StringToUTF16Ptr(title)
+		setWindowText.Call(wnd, uintptr(unsafe.Pointer(ptr)))
+	})
 }
 
 type _COMObject struct{}

zenity.go

@@ -73,7 +73,7 @@ func Title(title string) Option {
 // DialogIcon is the enumeration for dialog icons.
 type DialogIcon int
 
-// Icons for
+// The stock dialog icons.
 const (
 	ErrorIcon DialogIcon = iota + 1
 	WarningIcon
@@ -87,6 +87,8 @@ func Icon(icon DialogIcon) Option {
 }
 
 // Context returns an Option to set a Context that can dismiss the dialog.
+//
+// Dialogs dismissed by the Context return Context.Err.
 func Context(ctx context.Context) Option {
 	return funcOption(func(o *options) { o.ctx = ctx })
 }