From 093f042cc5e6ddfc6909ae0d2cb2d603a529c5ea Mon Sep 17 00:00:00 2001
From: Angelo Verlain <geoangercola@gmail.com>
Date: Tue, 26 Dec 2023 21:19:51 +0200
Subject: [PATCH] allow setting vfuncs provided by interfaces

---
 src/bindings/girepository.js |  1 +
 src/types/callable.js        | 39 +++++++++++++++++++++++++++---------
 2 files changed, 30 insertions(+), 10 deletions(-)

diff --git a/src/bindings/girepository.js b/src/bindings/girepository.js
index 0b1cc06..a15132c 100644
--- a/src/bindings/girepository.js
+++ b/src/bindings/girepository.js
@@ -101,6 +101,7 @@ const { g } = openLib(libName("girepository-1.0", 1), {
       get_vfunc: $pointer($pointer, $i32),
       get_n_properties: $i32($pointer),
       get_property: $pointer($pointer, $i32),
+      get_iface_struct: $pointer($pointer),
     },
     property_info: {
       get_flags: $i32($pointer),
diff --git a/src/types/callable.js b/src/types/callable.js
index 8d00a8f..84bb20e 100644
--- a/src/types/callable.js
+++ b/src/types/callable.js
@@ -137,24 +137,43 @@ export function handleCallable(target, info) {
         set(value) {
           const cName = g.base_info.get_name(info);
 
-          const objectInfo = g.base_info.get_container(info);
-          const classStruct = g.object_info.get_class_struct(objectInfo);
-          const fieldInfo = g.struct_info.find_field(classStruct, cName);
+          const containerInfo = g.base_info.get_container(info);
+          const containerType = g.base_info.get_type(containerInfo);
+
+          let containerStruct, pointer;
+
+          if (containerType === GIInfoType.INTERFACE) {
+            // we are setting a vfunc provided by an interface
+            containerStruct = g.interface_info.get_iface_struct(containerInfo);
+            const klass = g.type_class.ref(
+              Reflect.getOwnMetadata("gi:gtype", this.constructor),
+            );
+            // get the pointer to the interface struct of this class
+            pointer = g.type_interface.peek(
+              klass,
+              g.registered_type_info.get_g_type(containerInfo),
+            );
+          } else {
+            // we are directly setting a vfunc provided by a class
+            containerStruct = g.object_info.get_class_struct(containerInfo);
+            pointer = g.type_class.ref(
+              Reflect.getOwnMetadata("gi:gtype", this.constructor),
+            );
+          }
+
+          const fieldInfo = g.struct_info.find_field(containerStruct, cName);
 
           if (!fieldInfo) {
-            // This vfunc doesn't have a corresponding field in the class struct
+            // This vfunc doesn't have a corresponding field in the class or
+            // interface struct
             return;
           }
 
-          const klass = g.type_class.ref(
-            Reflect.getOwnMetadata("gi:gtype", this.constructor),
-          );
-
-          const cb = createCallback(info, value);
+          const cb = createCallback(info, value, this);
           const offset = g.field_info.get_offset(fieldInfo);
           const dataView = new ExtendedDataView(
             deref_buf(
-              klass,
+              pointer,
               offset + 8,
               offset,
             ),