Fix unsetting Clipbord / Add internal clip_wait logic to setting an…

…d retrieving `Clipboard`, so that those accesses always succeed (or explicitly show an error)

src/cmd/misc/clip-wait.cr

@@ -4,20 +4,36 @@ class Cmd::Misc::ClipWait < Cmd::Base
 	def self.max_args; 1 end
 	def self.sets_error_level; true end
 	def run(thread, args)
-		timeout_sec = args[0]?.try &.to_f?
-		start = Time.monotonic
+		timeout = args[0]?.try &.to_f?.try &.seconds
+		success = ClipWait.clip_wait(thread.runner.display.gtk, timeout) do |clp|
+			! clp.empty?
+		end
+		success ? "0" : "1"
+	end
+
+	# Waits until the clipboard passes the *&block*. Increases the sleep time inbetween operations
+	# slightly exponentially, but sleeps max. 0.5 seconds.
+	# Returns `true` when the *&block* returns true or `false` when *timeout* was exceeded.
+	def self.clip_wait(gtk, timeout : Time::Span? = nil, &block : ::String -> Bool)
 		# The following works great and low on performance, but it only checks for the *possibility*
 		# to retrieve text, even when it's empty:
 		# thread.runner.display.gtk.clipboard &.wait_is_text_available
 		# So we need to resort to looping which you could also easily do with ahk code itself.
 		back_off_wait = 5.milliseconds
-		while (txt = thread.runner.display.gtk.clipboard &.wait_for_text || "").empty?
-			if timeout_sec
-				return "1" if Time.monotonic - start > timeout_sec.seconds
+		start = Time.monotonic
+		loop do
+			txt = gtk.clipboard &.wait_for_text || ""
+			if yield(txt)
+				break
+			end
+			if timeout
+				if Time.monotonic - start > timeout
+					return false
+				end
 			end
 			sleep back_off_wait
 			back_off_wait = ::Math.min(back_off_wait * 1.2, 0.5.seconds)
 		end
-		"0"
+		true
 	end
 end

src/run/display/gtk.cr

@@ -54,6 +54,46 @@ module Run
 				block.call(clip)
 			end
 		end
+		def set_clipboard(text : String)
+			if text.empty?
+				clipboard do |clip|
+					# clip.clear # Doesn't do anything
+					# Doesn't work for access from outside of ahkx11 itself, even though https://stackoverflow.com/q/2418487 says so. Maybe a Crystal GIR bug?:
+					# clip.set_text("", 0)
+					# Ugly but works:
+					clip.image = GdkPixbuf::Pixbuf.new
+				end
+				if ! Cmd::Misc::ClipWait.clip_wait(self, 2.seconds, &.empty?)
+					raise Run::RuntimeException.new "Unsetting Clipboard failed [1]"
+				end
+				# But even now that we have confirmation that it was unset, the clipboard is sometimes still
+				# in the process of being reported to the active window. Setting it to a text and then unsetting
+				# it again seems to resolve it somehow. All of this is necessary, putting a sleep of the same duration
+				# instead is not enough.
+				clipboard do |clip|
+					clip.set_text("_ahk_x11_clipboard_internal", 27)
+					clip.store
+				end
+				if ! Cmd::Misc::ClipWait.clip_wait(self, 2.seconds, &.==("_ahk_x11_clipboard_internal"))
+					raise Run::RuntimeException.new "Unsetting Clipboard failed [2]"
+				end
+				clipboard do |clip|
+					clip.set_text("", 0)
+					clip.store
+				end
+				if ! Cmd::Misc::ClipWait.clip_wait(self, 2.seconds, &.empty?)
+					raise Run::RuntimeException.new "Unsetting Clipboard failed [3]"
+				end
+			else
+				clipboard do |clip|
+					clip.set_text(text, text.size)
+					clip.store
+				end
+				if ! Cmd::Misc::ClipWait.clip_wait(self, 2.seconds, &.==(text))
+					raise Run::RuntimeException.new "Setting Clipboard failed"
+				end
+			end
+		end
 
 		# Can't use @[Flags] because some values are *not* strict 2^n
 		enum MsgBoxOptions

src/run/runner.cr

@@ -210,16 +210,7 @@ module Run
 			down = var.downcase
 			case down
 			when "clipboard"
-				display.gtk.clipboard do |clip|
-					if value.empty?
-						# clip.clear # Doesn't do anything
-						# clip.set_text("", 0) # Doesn't work outside of ahkx11 itself, even though https://stackoverflow.com/q/2418487 says so. Maybe a Crystal GIR bug?
-						clip.image = GdkPixbuf::Pixbuf.new # Ugly but works
-					else
-						clip.set_text(value, value.size)
-					end
-					clip.store
-				end
+				display.gtk.set_clipboard(value)
 			else
 				return if @built_in_static_vars[down]? || get_global_built_in_computed_var(down)
 				{% if ! flag?(:release) %}