Removed Request completely, also updating the uitask files. Also renamed xperform to doissue for consistency.

redo/request.go

@@ -1,69 +0,0 @@
-// 6 july 2014
-
-package ui
-
-// Doer is a channel that takes Requests returned by the various functions and methods of package ui.
-// There are two main Doers: ui.Do, which is for outside event handlers, and the Doer passed into an event handler function.
-// You should not create or use your own Doers; these are meaningless.
-type Doer chan *Request
-
-// Do is the main way to issue requests to package ui.
-// Requests returned by the various functions and methods of package ui should be sent across Do to have them performed.
-// When an event is dispatched to an event handler, that event handler will receive a new Doer which is active for the life of the event handler, and any requests made to Do will block until the event handler returns.
-var Do = make(Doer)
-
-// Request represents a request issued to the package.
-// These are returned by the various functions and methods of package ui and are sent to either Do or to the currently active event handler channel.
-// There are also several convenience functions that perfrom common operations with requests.
-type Request struct {
-	op		func()
-	resp		chan interface{}
-}
-
-// Response returns a channel which is pulsed exactly once, then immeidately closed, with the response from the function that issued the request.
-// If the function does not return a value, this value will be the zero value of struct{}.
-// Otherwise, the type of this value depends on the function that created the Request.
-func (r *Request) Response() <-chan interface{} {
-	return r.resp
-}
-
-// Wait is a convenience function that performs a Request and waits for that request to be processed.
-// If the request returns a value, it is discarded.
-// You should generally use Wait on functions that do not return a value.
-// See the documentation of Bool for an example.
-func Wait(c Doer, r *Request) {
-	c <- r
-	<-r.resp
-}
-
-// Bool is a convenience function that performs a Request that returns a bool, waits for that request to be processed, and returns the result.
-// For example:
-// 	if ui.Bool(ui.Do, checkbox.Checked()) { /* do stuff */ }
-func Bool(c Doer, r *Request) bool {
-	c <- r
-	return (<-r.resp).(bool)
-}
-
-// Int is like Bool, but for int.
-func Int(c Doer, r *Request) int {
-	c <- r
-	return (<-r.resp).(int)
-}
-
-// String is like Bool, but for string.
-func String(c Doer, r *Request) string {
-	c <- r
-	return (<-r.resp).(string)
-}
-
-// IntSlice is like Bool, but for []int.
-func IntSlice(c Doer, r *Request) []int {
-	c <- r
-	return (<-r.resp).([]int)
-}
-
-// StringSlice is like Bool, but for []string.
-func StringSlice(c Doer, r *Request) []string {
-	c <- r
-	return (<-r.resp).([]string)
-}

redo/uitask.go

@@ -14,53 +14,32 @@ func Go() error {
 	if err := uiinit(); err != nil {
 		return err
 	}
-	go uitask(Do)
 	uimsgloop()
 	return nil
 }
 
-// Stop issues a Request for package ui to stop and returns immediately.
+// Do performs f on the main loop, as if it were an event handler.
+// It waits for f to execute before returning.
+// Do cannot be called within event handlers or within Do itself.
+func Do(f func()) {
+	done := make(chan struct{})
+	defer close(done)
+	issue(func() {
+		f()
+		done <- struct{}{}
+	})
+	<-done
+}
+
+// Stop informs package ui that it should stop.
+// Stop then returns immediately.
 // Some time after this request is received, Go() will return without performing any final cleanup.
-// Stop is internally issued to Do, so it will not be registered until any event handlers and dialog boxes return.
+// Stop will not have an effect until any event handlers or dialog boxes presently active return.
+// (TODO make sure this is the case for dialog boxes)
 func Stop() {
-	go func() {
+	issue(uistop)
-		c := make(chan interface{})
-		Do <- &Request{
-			op:		func() {
-				uistop()
-				c <- struct{}{}
-			},
-			resp:		c,
-		}
-		<-c
-	}()
 }
 
-// This is the ui main loop.
-// It is spawned by Go as a goroutine.
-// It can also be called recursively using the recur/unrecur chain.
-func uitask(doer Doer) {
-	for {
-		select {
-		case req := <-doer:
-			// TODO foreign event
-			issue(req)
-		case rec := <-recur:		// want to perform event
-			c := make(Doer)
-			rec <- c
-			uitask(c)
-		case <-unrecur:		// finished with event
-			close(doer)
-			return
-		}
-	}
-}
-
-// Send a channel over recur to have uitask() above enter a recursive loop in which the Doer sent back becomes the active request handler.
-// Pulse unrecur when finished.
-var recur = make(chan chan Doer)
-var unrecur = make(chan struct{})
-
 type event struct {
 	// All events internally return bool; those that don't will be wrapped around to return a dummy value.
 	do		func(c Doer) bool
@@ -105,38 +84,16 @@ func (e *event) setbool(f func(Doer) bool) {
 // This is the common code for running an event.
 // It runs on the main thread without a message pump; it provides its own.
 func (e *event) fire() bool {
-	cc := make(chan Doer)
+	e.lock.Lock()
-	recur <- cc
+	defer e.lock.Unlock()
-	c := <-cc
-	close(cc)
-	result := false
-	finished := make(chan struct{})
-	go func() {
-		e.lock.Lock()
-		defer e.lock.Unlock()
 
-		result = e.do(c)
+	return e.do(c)
-		finished <- struct{}{}
-	}()
-	<-finished
-	close(finished)
-	// leave the event handler; leave it only after returning from the OS-side event handler so we must issue it like a normal Request
-	issue(&Request{
-		op:		func() {
-			unrecur <- struct{}{}
-		},
-		// unfortunately, closing a nil channel causes a panic
-		// therefore, we have to make a dummy channel
-		// TODO add conditional checks to the request handler instead?
-		resp:		make(chan interface{}),
-	})
-	return result
 }
 
-// Common code for performing a Request.
+// Common code for performing a requested action (ui.Do() or ui.Stop()).
 // This should run on the main thread.
 // Implementations of issue() should call this.
-func perform(req *Request) {
+func perform(fp unsafe.Pointer) {
-	req.op()
+	f := (*func())(fp)
-	close(req.resp)
+	(*f)()
 }

redo/uitask_darwin.go

@@ -25,12 +25,11 @@ func uistop() {
 	C.uistop()
 }
 
-func issue(req *Request) {
+func issue(f func()) {
-	C.issue(unsafe.Pointer(req))
+	C.issue(unsafe.Pointer(&f))
 }
 
 //export doissue
-func doissue(r unsafe.Pointer) {
+func doissue(fp unsafe.Pointer) {
-	req := (*Request)(unsafe.Pointer(r))
+	perform(fp)
-	perform(req)
 }

redo/uitask_unix.go

@@ -27,13 +27,12 @@ func uistop() {
 	C.gtk_main_quit()
 }
 
-func issue(req *Request) {
+func issue(f func()) {
-	C.gdk_threads_add_idle(C.GSourceFunc(C.doissue), C.gpointer(unsafe.Pointer(req)))
+	C.gdk_threads_add_idle(C.GSourceFunc(C.doissue), C.gpointer(unsafe.Pointer(&f)))
 }
 
 //export doissue
 func doissue(data C.gpointer) C.gboolean {
-	req := (*Request)(unsafe.Pointer(data))
+	perform(unsafe.Pointer(data))
-	perform(req)
 	return C.FALSE		// don't repeat
 }

redo/uitask_windows.c

@@ -38,7 +38,7 @@ static LRESULT CALLBACK msgwinproc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM l
 	case WM_COMMAND:
 		return forwardCommand(hwnd, uMsg, wParam, lParam);
 	case msgRequest:
-		xperform((void *) lParam);
+		doissue((void *) lParam);
 		return 0;
 	default:
 		return DefWindowProcW(hwnd, uMsg, wParam, lParam);

redo/uitask_windows.go

@@ -41,8 +41,8 @@ func uistop() {
 	C.PostQuitMessage(0)
 }
 
-func issue(req *Request) {
+func issue(f func()) {
-	C.issue(unsafe.Pointer(req))
+	C.issue(unsafe.Pointer(&f))
 }
 
 func makemsgwin() error {
@@ -55,8 +55,7 @@ func makemsgwin() error {
 	return nil
 }
 
-//export xperform
+//export doissue
-func xperform(xreq unsafe.Pointer) {
+func doissue(fp unsafe.Pointer) {
-	req := (*Request)(xreq)
+	perform(fp)
-	perform(req)
 }