[gjs: 2/12] function: Use gatomicrefcount for trampoline refcounting

[Philip Chimento <pchimento src gnome org>]

commit e2f9cf808fd3672f14326befabc3d523842c7d7e
Author: Marco Trevisan (Treviño) <mail 3v1n0 net>
Date:   Wed Sep 2 19:35:43 2020 +0200

    function: Use gatomicrefcount for trampoline refcounting
    
    Since we depend on GLib 2.58 that includes this, let's just use it

 gi/function.cpp | 9 +++------
 gi/function.h   | 3 ++-
 2 files changed, 5 insertions(+), 7 deletions(-)
---
diff --git a/gi/function.cpp b/gi/function.cpp
index f3408da4..b0cb101b 100644
--- a/gi/function.cpp
+++ b/gi/function.cpp
@@ -93,17 +93,14 @@ GJS_DEFINE_PRIV_FROM_JS(Function, gjs_function_class)
 
 GjsCallbackTrampoline* gjs_callback_trampoline_ref(
     GjsCallbackTrampoline* trampoline) {
-    trampoline->ref_count++;
+    g_atomic_ref_count_inc(&trampoline->ref_count);
     return trampoline;
 }
 
 void
 gjs_callback_trampoline_unref(GjsCallbackTrampoline *trampoline)
 {
-    /* Not MT-safe, like all the rest of GJS */
-
-    trampoline->ref_count--;
-    if (trampoline->ref_count == 0) {
+    if (g_atomic_ref_count_dec(&trampoline->ref_count)) {
         g_clear_pointer(&trampoline->js_function, g_closure_unref);
         if (trampoline->info && trampoline->closure)
             g_callable_info_free_closure(trampoline->info, trampoline->closure);
@@ -550,7 +547,7 @@ GjsCallbackTrampoline* gjs_callback_trampoline_new(
 
     trampoline = g_new(GjsCallbackTrampoline, 1);
     new (trampoline) GjsCallbackTrampoline();
-    trampoline->ref_count = 1;
+    g_atomic_ref_count_init(&trampoline->ref_count);
     trampoline->info = callable_info;
     g_base_info_ref((GIBaseInfo*)trampoline->info);
 
diff --git a/gi/function.h b/gi/function.h
index 2b2ea106..98d09d0f 100644
--- a/gi/function.h
+++ b/gi/function.h
@@ -29,6 +29,7 @@
 #include <ffi.h>
 #include <girepository.h>
 #include <glib-object.h>
+#include <glib.h>
 
 #include <js/RootingAPI.h>
 #include <js/TypeDecls.h>
@@ -48,7 +49,7 @@ typedef enum {
 } GjsParamType;
 
 struct GjsCallbackTrampoline {
-    int ref_count;
+    gatomicrefcount ref_count;
     GICallableInfo *info;
 
     GClosure *js_function;