[gjs/ewlsh/use-new-gi-callable-api] gi: Use new GObject Introspection callable API

[Evan Welsh <ewlsh src gnome org>]

commit 21f85e8beb08b0a0e2c7d9d84295820dc53b55af
Author: Evan Welsh <contact evanwelsh com>
Date:   Sun Mar 6 14:36:10 2022 -0800

    gi: Use new GObject Introspection callable API
    
    This avoids misusing the closure pointer by creating a clear
    separation between the native closure pointer and the pointer
    to the libffi closure.
    
    Fixes #428

 gi/arg-cache.cpp |  2 +-
 gi/function.cpp  | 39 ++++++++++++++++++++++++---------------
 gi/function.h    |  9 ++++++++-
 gi/object.cpp    |  4 ++--
 4 files changed, 35 insertions(+), 19 deletions(-)
---
diff --git a/gi/arg-cache.cpp b/gi/arg-cache.cpp
index 83c4ad4da..177f246f4 100644
--- a/gi/arg-cache.cpp
+++ b/gi/arg-cache.cpp
@@ -826,7 +826,7 @@ GJS_JSAPI_RETURN_CONVENTION
 bool CallbackIn::in(JSContext* cx, GjsFunctionCallState* state, GIArgument* arg,
                     JS::HandleValue value) {
     GjsCallbackTrampoline* trampoline;
-    ffi_closure* closure;
+    void* closure;
 
     if (value.isNull() && m_nullable) {
         closure = nullptr;
diff --git a/gi/function.cpp b/gi/function.cpp
index 716acc8ec..5c4fa4a28 100644
--- a/gi/function.cpp
+++ b/gi/function.cpp
@@ -640,8 +640,13 @@ GjsCallbackTrampoline::GjsCallbackTrampoline(
 }
 
 GjsCallbackTrampoline::~GjsCallbackTrampoline() {
-    if (m_info && m_closure)
+    if (m_info && m_closure) {
+#if GI_CHECK_VERSION(1, 71, 0)
+        g_callable_info_destroy_closure(m_info, m_closure);
+#else
         g_callable_info_free_closure(m_info, m_closure);
+#endif
+    }
 }
 
 void GjsCallbackTrampoline::mark_forever() {
@@ -652,6 +657,23 @@ void GjsCallbackTrampoline::prepare_shutdown() {
     s_forever_closure_list.clear();
 }
 
+ffi_closure* GjsCallbackTrampoline::create_closure() {
+    auto callback = [](ffi_cif*, void* result, void** ffi_args, void* data) {
+        auto** args = reinterpret_cast<GIArgument**>(ffi_args);
+        g_assert(data && "Trampoline data is not set");
+        Gjs::Closure::Ptr trampoline(static_cast<GjsCallbackTrampoline*>(data),
+                                     GjsAutoTakeOwnership());
+
+        trampoline.as<GjsCallbackTrampoline>()->callback_closure(args, result);
+    };
+
+#if GI_CHECK_VERSION(1, 71, 0)
+    return g_callable_info_create_closure(m_info, &m_cif, callback, this);
+#else
+    return g_callable_info_prepare_closure(m_info, &m_cif, callback, this);
+#endif
+}
+
 bool GjsCallbackTrampoline::initialize() {
     g_assert(is_valid());
     g_assert(!m_closure);
@@ -720,20 +742,7 @@ bool GjsCallbackTrampoline::initialize() {
         }
     }
 
-    m_closure = g_callable_info_prepare_closure(
-        m_info, &m_cif,
-        [](ffi_cif*, void* result, void** ffi_args, void* data) {
-            auto** args = reinterpret_cast<GIArgument**>(ffi_args);
-            g_assert(data && "Trampoline data is not set");
-            Gjs::Closure::Ptr trampoline(
-                static_cast<GjsCallbackTrampoline*>(data),
-                GjsAutoTakeOwnership());
-
-            trampoline.as<GjsCallbackTrampoline>()->callback_closure(args,
-                                                                     result);
-        },
-        this);
-
+    m_closure = create_closure();
     return true;
 }
 
diff --git a/gi/function.h b/gi/function.h
index a6e9b82dd..799c14903 100644
--- a/gi/function.h
+++ b/gi/function.h
@@ -49,13 +49,20 @@ struct GjsCallbackTrampoline : public Gjs::Closure {
 
     ~GjsCallbackTrampoline();
 
-    constexpr ffi_closure* closure() const { return m_closure; }
+    void* closure() const {
+#if GI_CHECK_VERSION(1, 71, 0)
+        return g_callable_info_get_closure_native_address(m_info, m_closure);
+#else
+        return m_closure;
+#endif
+    }
 
     void mark_forever();
 
     static void prepare_shutdown();
 
  private:
+    ffi_closure* create_closure();
     GJS_JSAPI_RETURN_CONVENTION bool initialize();
     GjsCallbackTrampoline(JSContext* cx, JS::HandleFunction function,
                           GICallableInfo* callable_info, GIScopeType scope,
diff --git a/gi/object.cpp b/gi/object.cpp
index a53f9e525..45457202d 100644
--- a/gi/object.cpp
+++ b/gi/object.cpp
@@ -3004,7 +3004,7 @@ bool ObjectPrototype::hook_up_vfunc_impl(JSContext* cx,
 
     if (field_info) {
         gint offset;
-        gpointer method_ptr;
+        void* method_ptr;
         GjsCallbackTrampoline *trampoline;
 
         offset = g_field_info_get_offset(field_info);
@@ -3032,7 +3032,7 @@ bool ObjectPrototype::hook_up_vfunc_impl(JSContext* cx,
             trampoline, nullptr,
             [](void*, GClosure* closure) { g_closure_unref(closure); });
 
-        *reinterpret_cast<ffi_closure**>(method_ptr) = trampoline->closure();
+        *reinterpret_cast<void**>(method_ptr) = trampoline->closure();
     }
 
     return true;