From 18d526c2d3e67c3d285950247b6df084a0458c98 Mon Sep 17 00:00:00 2001
From: Hajime Hoshi <hajimehoshi@gmail.com>
Date: Tue, 23 Feb 2021 16:52:09 +0900
Subject: [PATCH] internal/uidriver/glfw: Bug fix: Crash when returning from
 fullscreen

ForceUpdate was called unexpectedly inside Update. This caused the
race condition.

Closes #1505
---
 internal/glfw/glfw_notwindows.go |  8 ++++++--
 internal/glfw/glfw_windows.go    | 10 +++++++---
 internal/uidriver/glfw/ui.go     |  6 ++++++
 3 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/internal/glfw/glfw_notwindows.go b/internal/glfw/glfw_notwindows.go
index 4f8f5e810..1b4a7e1e7 100644
--- a/internal/glfw/glfw_notwindows.go
+++ b/internal/glfw/glfw_notwindows.go
@@ -35,7 +35,7 @@ func (w windows) add(win *glfw.Window) *Window {
 	if win == nil {
 		return nil
 	}
-	ww := &Window{win}
+	ww := &Window{w: win}
 	windowsM.Lock()
 	w[win] = ww
 	windowsM.Unlock()
@@ -87,6 +87,8 @@ func (m *Monitor) GetVideoMode() *VidMode {
 
 type Window struct {
 	w *glfw.Window
+
+	prevSizeCallback SizeCallback
 }
 
 func (w *Window) Destroy() {
@@ -191,7 +193,9 @@ func (w *Window) SetSizeCallback(cbfun SizeCallback) (previous SizeCallback) {
 		}
 	}
 	w.w.SetSizeCallback(gcb)
-	return nil // TODO
+	prev := w.prevSizeCallback
+	w.prevSizeCallback = cbfun
+	return prev
 }
 
 func (w *Window) SetIcon(images []image.Image) {
diff --git a/internal/glfw/glfw_windows.go b/internal/glfw/glfw_windows.go
index c13595cf7..8cc6b880f 100644
--- a/internal/glfw/glfw_windows.go
+++ b/internal/glfw/glfw_windows.go
@@ -42,7 +42,7 @@ func (w glfwWindows) add(win uintptr) *Window {
 	if win == 0 {
 		return nil
 	}
-	ww := &Window{win}
+	ww := &Window{w: win}
 	glfwWindowsM.Lock()
 	w[win] = ww
 	glfwWindowsM.Unlock()
@@ -91,6 +91,8 @@ func (m *Monitor) GetVideoMode() *VidMode {
 
 type Window struct {
 	w uintptr
+
+	prevSizeCallback SizeCallback
 }
 
 func (w *Window) Destroy() {
@@ -218,7 +220,7 @@ func (w *Window) SetScrollCallback(cbfun ScrollCallback) (previous ScrollCallbac
 	return nil // TODO
 }
 
-func (w *Window) SetSizeCallback(cbfun SizeCallback) (previous FramebufferSizeCallback) {
+func (w *Window) SetSizeCallback(cbfun SizeCallback) (previous SizeCallback) {
 	var gcb uintptr
 	if cbfun != nil {
 		gcb = windows.NewCallbackCDecl(func(window uintptr, width int, height int) uintptr {
@@ -228,7 +230,9 @@ func (w *Window) SetSizeCallback(cbfun SizeCallback) (previous FramebufferSizeCa
 	}
 	glfwDLL.call("glfwSetWindowSizeCallback", w.w, gcb)
 	panicError()
-	return nil // TODO
+	prev := w.prevSizeCallback
+	w.prevSizeCallback = cbfun
+	return prev
 }
 
 func (w *Window) SetIcon(images []image.Image) {
diff --git a/internal/uidriver/glfw/ui.go b/internal/uidriver/glfw/ui.go
index dc85c9a95..c0b69290c 100644
--- a/internal/uidriver/glfw/ui.go
+++ b/internal/uidriver/glfw/ui.go
@@ -946,6 +946,12 @@ func (u *UserInterface) setWindowSize(width, height int, fullscreen bool) {
 	// swap buffers here before SetSize is called.
 	u.swapBuffers()
 
+	// Do not fire the callback of SetSize. This callback can be invoked by SetMonitor or SetSize.
+	// ForceUpdate is called from the callback.
+	// While setWindowSize can be called from Update, calling ForceUpdate inside Update is illegal (#1505).
+	f := u.window.SetSizeCallback(nil)
+	defer u.window.SetSizeCallback(f)
+
 	var windowRecreated bool
 
 	if fullscreen {