Fix deadlock in Stop

Closes #23

attribute.go

@@ -15,7 +15,6 @@ type Attr interface {
 
 type AttrKind int; const (
 	AttrKindColor AttrKind = iota
-	AttrKindIcon
 	AttrKindTexture
 	AttrKindTextureMode
 	AttrKindBorder
@@ -33,9 +32,6 @@ type AttrKind int; const (
 
 // AttrColor sets the background color of a box.
 type AttrColor struct { color.Color }
-// AttrIcon sets the icon of a box to a named icon. It has the same end result
-// as setting the texture of a box to a centered icon texture.
-type AttrIcon struct { Icon Icon; Size IconSize }
 // AttrTexture sets the texture of a box to a texture.
 type AttrTexture struct { canvas.Texture }
 // AttrTextureMode sets the rendering mode of a box's texture.
@@ -67,10 +63,6 @@ type AttrLayout struct { Layout }
 func AColor (col color.Color) AttrColor {
 	return AttrColor { Color: col }
 }
-// AIcon is a convenience constructor for the icon attribute.
-func AIcon (icon Icon, size IconSize) AttrIcon {
-	return AttrIcon { Icon: icon, Size: size }
-}
 // ATexture is a convenience constructor for the texture attribute.
 func ATexture (texture canvas.Texture) AttrTexture {
 	return AttrTexture { Texture: texture }
@@ -133,14 +125,6 @@ func (this AttrColor) Equals (other Attr) bool {
 	}
 }
 // Equals returns true if both attributes can reasonably be declared equal.
-func (this AttrIcon) Equals (other Attr) bool {
-	if other, ok := other.(AttrIcon); ok {
-		return this == other
-	} else {
-		return false
-	}
-}
-// Equals returns true if both attributes can reasonably be declared equal.
 func (this AttrTexture) Equals (other Attr) bool {
 	if other, ok := other.(AttrTexture); ok {
 		return this == other
@@ -251,7 +235,6 @@ func (this AttrLayout) Equals (other Attr) bool {
 }
 
 func (AttrColor)       Kind () AttrKind { return AttrKindColor }
-func (AttrIcon)        Kind () AttrKind { return AttrKindIcon }
 func (AttrTexture)     Kind () AttrKind { return AttrKindTexture }
 func (AttrTextureMode) Kind () AttrKind { return AttrKindTextureMode }
 func (AttrBorder)      Kind () AttrKind { return AttrKindBorder }
@@ -267,7 +250,6 @@ func (AttrOverflow)    Kind () AttrKind { return AttrKindOverflow }
 func (AttrLayout)      Kind () AttrKind { return AttrKindLayout }
 
 func (AttrColor)       attr () { }
-func (AttrIcon)        attr () { }
 func (AttrTexture)     attr () { }
 func (AttrTextureMode) attr () { }
 func (AttrBorder)      attr () { }

icon.go

@@ -16,6 +16,7 @@ type Icon string
 // A list of standard icon IDs. This is roughly based off of the XDG Icon Naming
 // Specification (https://specifications.freedesktop.org/icon-naming-spec/icon-naming-spec-latest.html).
 const (
+	// IconUnknown should be a blank space the size of a regular icon.
 	IconUnknown                      Icon = ""
 
 	// actions
@@ -90,6 +91,9 @@ const (
 	// actions: list
 	IconListAdd                      Icon = "ListAdd"
 	IconListRemove                   Icon = "ListRemove"
+	IconListChoose                   Icon = "ListChoose"
+	IconListExpand                   Icon = "ListExpand"
+	IconListContract                 Icon = "ListExpand"
 	// actions: mail
 	IconMailForward                  Icon = "MailForward"
 	IconMailMarkImportant            Icon = "MailMarkImportant"
@@ -275,9 +279,6 @@ const (
 	IconPlaceHistory                 Icon = "PlaceHistory"
 	IconPlacePreferences             Icon = "PlacePreferences"
 
-	// status: checkbox
-	IconCheckboxChecked              Icon = "CheckboxChecked"
-	IconCheckboxUnchecked            Icon = "CheckboxUnchecked"
 	// status: appointments
 	IconAppointmentMissed            Icon = "AppointmentMissed"
 	IconAppointmentSoon              Icon = "AppointmentSoon"

object.go

@@ -287,6 +287,13 @@ type BoxArranger interface {
 // themselves are completely transparent, and become opaque once an opaque
 // object is added as their root.
 type Window interface {
+	// Bounds returns the bounds of the window including its frame, if
+	// possible. This means that the top-left point of the bounds will be
+	// either zero or negative.
+	Bounds () image.Rectangle
+	// InnerBounds returns the inner bounds of the window, not including its
+	// frame. This means that the top-left point of the bounds will be zero.
+	InnerBounds () image.Rectangle
 	// SetRoot sets the root child of the window. There can only be one at
 	// a time, and setting it will remove the current child if there is one.
 	SetRoot (Object)

tomo.go

@@ -1,24 +1,44 @@
 package tomo
 
+import "sync"
 import "image"
 import "git.tebibyte.media/tomo/tomo/canvas"
 
-// Stop stops the backend, unblocking run. Run may be called again after calling
-// Stop.
+// TODO this really sucks. It might be a good idea to have Do be the entry point
+// for every off-thread call, and Stop should just call backend.Stop within
+// backend.Do. This is because Do is a queue and is not vulnerable to recursive
+// locking.
+
+var stopping bool
+var stoppingLock sync.Mutex
+func isStopping () bool {
+	stoppingLock.Lock()
+	defer stoppingLock.Unlock()
+	return stopping
+}
+func setStopping (is bool) {
+	stoppingLock.Lock()
+	defer stoppingLock.Unlock()
+	stopping = is
+}
+
+// Stop stops the currently running backend.
 func Stop () {
-	assertBackend()
-	backend.Stop()
-	
+	if isStopping() { return }
+	setStopping(true)
 	backendLock.Lock()
+	defer backendLock.Unlock()
+	if backend == nil { return }
+	backend.Stop()
 	backend = nil
-	backendLock.Unlock()
+	setStopping(false)
 }
 
 // Do performs a callback function in the event loop thread as soon as possible.
 func Do (callback func ()) {
 	backendLock.Lock()
+	defer backendLock.Unlock()
 	if backend != nil { backend.Do(callback) }
-	backendLock.Unlock()
 }
 
 // NewWindow creates and returns a window within the specified bounds on screen.