app/internal/wm: rename confusing app/internal/window

Package wm (for "window manager") is a better fit for the package, and
distinguishes it from the low-level package windows for the Windows API.

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

app/internal/wm/window.go

@@ -0,0 +1,106 @@
+// SPDX-License-Identifier: Unlicense OR MIT
+
+// package wm implements platform specific windows
+// and GPU contexts.
+package wm
+
+import (
+	"errors"
+
+	"gioui.org/gpu"
+	"gioui.org/io/event"
+	"gioui.org/io/pointer"
+	"gioui.org/io/system"
+	"gioui.org/unit"
+)
+
+type Options struct {
+	Width, Height       unit.Value
+	MinWidth, MinHeight unit.Value
+	MaxWidth, MaxHeight unit.Value
+	Title               string
+}
+
+type FrameEvent struct {
+	system.FrameEvent
+
+	Sync bool
+}
+
+type Callbacks interface {
+	SetDriver(d Driver)
+	Event(e event.Event)
+}
+
+type Context interface {
+	API() gpu.API
+	Present() error
+	MakeCurrent() error
+	Release()
+	Lock()
+	Unlock()
+}
+
+// ErrDeviceLost is returned from Context.Present when
+// the underlying GPU device is gone and should be
+// recreated.
+var ErrDeviceLost = errors.New("GPU device lost")
+
+// Driver is the interface for the platform implementation
+// of a window.
+type Driver interface {
+	// SetAnimating sets the animation flag. When the window is animating,
+	// FrameEvents are delivered as fast as the display can handle them.
+	SetAnimating(anim bool)
+	// ShowTextInput updates the virtual keyboard state.
+	ShowTextInput(show bool)
+	NewContext() (Context, error)
+
+	// ReadClipboard requests the clipboard content.
+	ReadClipboard()
+	// WriteClipboard requests a clipboard write.
+	WriteClipboard(s string)
+
+	// SetCursor updates the current cursor to name.
+	SetCursor(name pointer.CursorName)
+
+	// Close the window.
+	Close()
+}
+
+type windowRendezvous struct {
+	in   chan windowAndOptions
+	out  chan windowAndOptions
+	errs chan error
+}
+
+type windowAndOptions struct {
+	window Callbacks
+	opts   *Options
+}
+
+func newWindowRendezvous() *windowRendezvous {
+	wr := &windowRendezvous{
+		in:   make(chan windowAndOptions),
+		out:  make(chan windowAndOptions),
+		errs: make(chan error),
+	}
+	go func() {
+		var main windowAndOptions
+		var out chan windowAndOptions
+		for {
+			select {
+			case w := <-wr.in:
+				var err error
+				if main.window != nil {
+					err = errors.New("multiple windows are not supported")
+				}
+				wr.errs <- err
+				main = w
+				out = wr.out
+			case out <- main:
+			}
+		}
+	}()
+	return wr
+}