app: merge app/internal/wm into package app

The app and app/internal/wm packages are tightly coupled, requiring
quite a bit of forwarding types, values and constants from the internal
package to export it. Further, no other package imports package wm.

This change merges the two packages.

While here, drop the pre-Go 1.14 SIGPIPE workaround.

Signed-off-by: Elias Naur <mail@eliasnaur.com>

app/os_darwin.go

@@ -0,0 +1,237 @@
+// SPDX-License-Identifier: Unlicense OR MIT
+
+package app
+
+/*
+#include <Foundation/Foundation.h>
+
+__attribute__ ((visibility ("hidden"))) void gio_wakeupMainThread(void);
+__attribute__ ((visibility ("hidden"))) CFTypeRef gio_createDisplayLink(void);
+__attribute__ ((visibility ("hidden"))) void gio_releaseDisplayLink(CFTypeRef dl);
+__attribute__ ((visibility ("hidden"))) int gio_startDisplayLink(CFTypeRef dl);
+__attribute__ ((visibility ("hidden"))) int gio_stopDisplayLink(CFTypeRef dl);
+__attribute__ ((visibility ("hidden"))) void gio_setDisplayLinkDisplay(CFTypeRef dl, uint64_t did);
+__attribute__ ((visibility ("hidden"))) void gio_hideCursor();
+__attribute__ ((visibility ("hidden"))) void gio_showCursor();
+__attribute__ ((visibility ("hidden"))) void gio_setCursor(NSUInteger curID);
+
+static bool isMainThread() {
+	return [NSThread isMainThread];
+}
+
+static NSUInteger nsstringLength(CFTypeRef cstr) {
+	NSString *str = (__bridge NSString *)cstr;
+	return [str length];
+}
+
+static void nsstringGetCharacters(CFTypeRef cstr, unichar *chars, NSUInteger loc, NSUInteger length) {
+	NSString *str = (__bridge NSString *)cstr;
+	[str getCharacters:chars range:NSMakeRange(loc, length)];
+}
+*/
+import "C"
+import (
+	"errors"
+	"sync"
+	"sync/atomic"
+	"time"
+	"unicode/utf16"
+	"unsafe"
+
+	"gioui.org/io/pointer"
+)
+
+// displayLink is the state for a display link (CVDisplayLinkRef on macOS,
+// CADisplayLink on iOS). It runs a state-machine goroutine that keeps the
+// display link running for a while after being stopped to avoid the thread
+// start/stop overhead and because the CVDisplayLink sometimes fails to
+// start, stop and start again within a short duration.
+type displayLink struct {
+	callback func()
+	// states is for starting or stopping the display link.
+	states chan bool
+	// done is closed when the display link is destroyed.
+	done chan struct{}
+	// dids receives the display id when the callback owner is moved
+	// to a different screen.
+	dids chan uint64
+	// running tracks the desired state of the link. running is accessed
+	// with atomic.
+	running uint32
+}
+
+// displayLinks maps CFTypeRefs to *displayLinks.
+var displayLinks sync.Map
+
+var mainFuncs = make(chan func(), 1)
+
+// runOnMain runs the function on the main thread.
+func runOnMain(f func()) {
+	if C.isMainThread() {
+		f()
+		return
+	}
+	go func() {
+		mainFuncs <- f
+		C.gio_wakeupMainThread()
+	}()
+}
+
+//export gio_dispatchMainFuncs
+func gio_dispatchMainFuncs() {
+	for {
+		select {
+		case f := <-mainFuncs:
+			f()
+		default:
+			return
+		}
+	}
+}
+
+// nsstringToString converts a NSString to a Go string, and
+// releases the original string.
+func nsstringToString(str C.CFTypeRef) string {
+	if str == 0 {
+		return ""
+	}
+	defer C.CFRelease(str)
+	n := C.nsstringLength(str)
+	if n == 0 {
+		return ""
+	}
+	chars := make([]uint16, n)
+	C.nsstringGetCharacters(str, (*C.unichar)(unsafe.Pointer(&chars[0])), 0, n)
+	utf8 := utf16.Decode(chars)
+	return string(utf8)
+}
+
+func NewDisplayLink(callback func()) (*displayLink, error) {
+	d := &displayLink{
+		callback: callback,
+		done:     make(chan struct{}),
+		states:   make(chan bool),
+		dids:     make(chan uint64),
+	}
+	dl := C.gio_createDisplayLink()
+	if dl == 0 {
+		return nil, errors.New("app: failed to create display link")
+	}
+	go d.run(dl)
+	return d, nil
+}
+
+func (d *displayLink) run(dl C.CFTypeRef) {
+	defer C.gio_releaseDisplayLink(dl)
+	displayLinks.Store(dl, d)
+	defer displayLinks.Delete(dl)
+	var stopTimer *time.Timer
+	var tchan <-chan time.Time
+	started := false
+	for {
+		select {
+		case <-tchan:
+			tchan = nil
+			started = false
+			C.gio_stopDisplayLink(dl)
+		case start := <-d.states:
+			switch {
+			case !start && tchan == nil:
+				// stopTimeout is the delay before stopping the display link to
+				// avoid the overhead of frequently starting and stopping the
+				// link thread.
+				const stopTimeout = 500 * time.Millisecond
+				if stopTimer == nil {
+					stopTimer = time.NewTimer(stopTimeout)
+				} else {
+					// stopTimer is always drained when tchan == nil.
+					stopTimer.Reset(stopTimeout)
+				}
+				tchan = stopTimer.C
+				atomic.StoreUint32(&d.running, 0)
+			case start:
+				if tchan != nil && !stopTimer.Stop() {
+					<-tchan
+				}
+				tchan = nil
+				atomic.StoreUint32(&d.running, 1)
+				if !started {
+					started = true
+					C.gio_startDisplayLink(dl)
+				}
+			}
+		case did := <-d.dids:
+			C.gio_setDisplayLinkDisplay(dl, C.uint64_t(did))
+		case <-d.done:
+			return
+		}
+	}
+}
+
+func (d *displayLink) Start() {
+	d.states <- true
+}
+
+func (d *displayLink) Stop() {
+	d.states <- false
+}
+
+func (d *displayLink) Close() {
+	close(d.done)
+}
+
+func (d *displayLink) SetDisplayID(did uint64) {
+	d.dids <- did
+}
+
+//export gio_onFrameCallback
+func gio_onFrameCallback(dl C.CFTypeRef) {
+	if d, exists := displayLinks.Load(dl); exists {
+		d := d.(*displayLink)
+		if atomic.LoadUint32(&d.running) != 0 {
+			d.callback()
+		}
+	}
+}
+
+// windowSetCursor updates the cursor from the current one to a new one
+// and returns the new one.
+func windowSetCursor(from, to pointer.CursorName) pointer.CursorName {
+	if from == to {
+		return to
+	}
+	var curID int
+	switch to {
+	default:
+		to = pointer.CursorDefault
+		fallthrough
+	case pointer.CursorDefault:
+		curID = 1
+	case pointer.CursorText:
+		curID = 2
+	case pointer.CursorPointer:
+		curID = 3
+	case pointer.CursorCrossHair:
+		curID = 4
+	case pointer.CursorColResize:
+		curID = 5
+	case pointer.CursorRowResize:
+		curID = 6
+	case pointer.CursorGrab:
+		curID = 7
+	case pointer.CursorNone:
+		C.gio_hideCursor()
+		return to
+	}
+	if from == pointer.CursorNone {
+		C.gio_showCursor()
+	}
+	C.gio_setCursor(C.NSUInteger(curID))
+	return to
+}
+
+func (w *window) Wakeup() {
+	runOnMain(func() {
+		w.w.Event(wakeupEvent{})
+	})
+}