From 3237d60ee8878d6c6aedff401c7521d0e06b7233 Mon Sep 17 00:00:00 2001
From: gdivos <gdivos@gmail.com>
Date: Thu, 17 Jan 2019 20:58:14 +0100
Subject: [PATCH] Remove GTK timer source ID from main context on uninit

Restarting the main loop without removing the timer source results in
null-pointer dereference error in GTK.

https://developer.gnome.org/glib/stable/glib-The-Main-Event-Loop.html#mainloop-memory-management
---
 unix/main.c | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/unix/main.c b/unix/main.c
index 5d349d32..a4ad3514 100644
--- a/unix/main.c
+++ b/unix/main.c
@@ -22,11 +22,17 @@ const char *uiInit(uiInitOptions *o)
 	return NULL;
 }
 
-struct timer;		// TODO get rid of forward declaration
+struct timer {
+	int (*f)(void *);
+	void *data;
+	guint gtk_source_id;
+};
 
 static void uninitTimer(gpointer key, gpointer value, gpointer data)
 {
-	uiprivFree((struct timer *) key);
+	struct timer *t = (struct timer *) key;
+	g_source_remove(t->gtk_source_id);
+	uiprivFree(t);
 }
 
 void uiUninit(void)
@@ -119,17 +125,13 @@ void uiQueueMain(void (*f)(void *data), void *data)
 	gdk_threads_add_idle(doqueued, q);
 }
 
-struct timer {
-	int (*f)(void *);
-	void *data;
-};
-
 static gboolean doTimer(gpointer data)
 {
 	struct timer *t = (struct timer *) data;
 
 	if (!(*(t->f))(t->data)) {
 		g_hash_table_remove(timers, t);
+		g_source_remove(t->gtk_source_id);
 		uiprivFree(t);
 		return FALSE;
 	}
@@ -143,6 +145,6 @@ void uiTimer(int milliseconds, int (*f)(void *data), void *data)
 	t = uiprivNew(struct timer);
 	t->f = f;
 	t->data = data;
-	g_timeout_add(milliseconds, doTimer, t);
+	t->gtk_source_id = g_timeout_add(milliseconds, doTimer, t);
 	g_hash_table_add(timers, t);
 }