LibJS: Add Object::define_accessor()

This is a helper function based on the getter/setter definition logic from
ObjectExpression::execute() to look up an Accessor property if it already
exists, define a new Accessor property if it doesn't exist, and set the getter or
setter function on the Accessor.

2 files changed, 26 insertions, 0 deletions

diff --git a/Libraries/LibJS/Runtime/Object.cpp b/Libraries/LibJS/Runtime/Object.cpp
index 0b87bc57fd..2d1feb8ebd 100644
--- a/Libraries/LibJS/Runtime/Object.cpp
+++ b/Libraries/LibJS/Runtime/Object.cpp
@@ -427,6 +427,31 @@ bool Object::define_property(PropertyName property_name, Value value, PropertyAt
     return put_own_property(*this, property_name.as_string(), value, attributes, PutOwnPropertyMode::DefineProperty, throw_exceptions);
 }
 
+bool Object::define_accessor(PropertyName property_name, Function& getter_or_setter, bool is_getter, PropertyAttributes attributes, bool throw_exceptions)
+{
+    Accessor* accessor { nullptr };
+    auto property_metadata = shape().lookup(property_name.as_string());
+    if (property_metadata.has_value()) {
+        auto existing_property = get_direct(property_metadata.value().offset);
+        if (existing_property.is_accessor())
+            accessor = &existing_property.as_accessor();
+    }
+    if (!accessor) {
+        accessor = Accessor::create(interpreter(), nullptr, nullptr);
+        bool definition_success = define_property(property_name, accessor, attributes, throw_exceptions);
+        if (interpreter().exception())
+            return {};
+        if (!definition_success)
+            return false;
+    }
+    if (is_getter)
+        accessor->set_getter(&getter_or_setter);
+    else
+        accessor->set_setter(&getter_or_setter);
+
+    return true;
+}
+
 bool Object::put_own_property(Object& this_object, const FlyString& property_name, Value value, PropertyAttributes attributes, PutOwnPropertyMode mode, bool throw_exceptions)
 {
     ASSERT(!(mode == PutOwnPropertyMode::Put && value.is_accessor()));
diff --git a/Libraries/LibJS/Runtime/Object.h b/Libraries/LibJS/Runtime/Object.h
index 4cf78f822d..3723560e27 100644
--- a/Libraries/LibJS/Runtime/Object.h
+++ b/Libraries/LibJS/Runtime/Object.h
@@ -98,6 +98,7 @@ public:
 
     virtual bool define_property(const FlyString& property_name, const Object& descriptor, bool throw_exceptions = true);
     bool define_property(PropertyName, Value value, PropertyAttributes attributes = default_attributes, bool throw_exceptions = true);
+    bool define_accessor(PropertyName, Function& getter_or_setter, bool is_getter, PropertyAttributes attributes = default_attributes, bool throw_exceptions = true);
 
     bool define_native_function(const FlyString& property_name, AK::Function<Value(Interpreter&, GlobalObject&)>, i32 length = 0, PropertyAttributes attributes = default_attributes);
     bool define_native_property(const FlyString& property_name, AK::Function<Value(Interpreter&, GlobalObject&)> getter, AK::Function<void(Interpreter&, GlobalObject&, Value)> setter, PropertyAttributes attributes = default_attributes);