Add Object::define_own_property() (#228)

This commit introduces the NONE, READ_ONLY, DONT_ENUM and DONT_DELETE
property attributes.

src/binding.cc

@@ -626,9 +626,8 @@ int v8__String__WriteUtf8(const v8::String& self, v8::Isolate* isolate,
 }
 
 void v8__Template__Set(v8::Template& self, v8::Local<v8::Name> key,
-                       v8::Local<v8::Data> value) {
-  // TODO(bnoordhuis) Allow setting PropertyAttributes.
-  self.Set(key, value);
+                       v8::Local<v8::Data> value, v8::PropertyAttribute attr) {
+  self.Set(key, value, attr);
 }
 
 v8::ObjectTemplate* v8__ObjectTemplate__New(
@@ -673,6 +672,14 @@ MaybeBool v8__Object__CreateDataProperty(v8::Object& self,
   return maybe_to_maybe_bool(self.CreateDataProperty(context, key, value));
 }
 
+MaybeBool v8__Object__DefineOwnProperty(v8::Object& self,
+                                        v8::Local<v8::Context> context,
+                                        v8::Local<v8::Name> key,
+                                        v8::Local<v8::Value> value,
+                                        v8::PropertyAttribute attr) {
+  return maybe_to_maybe_bool(self.DefineOwnProperty(context, key, value, attr));
+}
+
 MaybeBool v8__Object__SetAccessor(v8::Object& self,
                                   v8::Local<v8::Context> context,
                                   v8::Local<v8::Name> key,

src/lib.rs

@@ -59,6 +59,7 @@ mod platform;
 mod primitive_array;
 mod primitives;
 mod promise;
+mod property_attribute;
 mod scope_traits;
 mod script;
 mod script_or_module;
@@ -107,6 +108,7 @@ pub use platform::Task;
 pub use primitive_array::PrimitiveArray;
 pub use primitives::*;
 pub use promise::{PromiseRejectEvent, PromiseRejectMessage, PromiseState};
+pub use property_attribute::*;
 pub use scope::CallbackScope;
 pub use scope::ContextScope;
 pub use scope::FunctionCallbackScope;

src/object.rs

@@ -8,6 +8,7 @@ use crate::Context;
 use crate::Local;
 use crate::Name;
 use crate::Object;
+use crate::PropertyAttribute;
 use crate::ToLocal;
 use crate::Value;
 
@@ -44,6 +45,13 @@ extern "C" {
     key: *const Name,
     value: *const Value,
   ) -> MaybeBool;
+  fn v8__Object__DefineOwnProperty(
+    object: &Object,
+    context: *const Context,
+    key: *const Name,
+    value: *const Value,
+    attr: PropertyAttribute,
+  ) -> MaybeBool;
   fn v8__Object__GetIdentityHash(object: &Object) -> int;
 
   fn v8__Array__New(isolate: *mut Isolate, length: int) -> *mut Array;
@@ -120,6 +128,24 @@ impl Object {
     unsafe { v8__Object__CreateDataProperty(self, &*context, &*key, &*value) }
   }
 
+  /// Implements DefineOwnProperty.
+  ///
+  /// In general, CreateDataProperty will be faster, however, does not allow
+  /// for specifying attributes.
+  ///
+  /// Returns true on success.
+  pub fn define_own_property(
+    &self,
+    context: Local<Context>,
+    key: Local<Name>,
+    value: Local<Value>,
+    attr: PropertyAttribute,
+  ) -> MaybeBool {
+    unsafe {
+      v8__Object__DefineOwnProperty(self, &*context, &*key, &*value, attr)
+    }
+  }
+
   pub fn get<'a>(
     &self,
     scope: &mut impl ToLocal<'a>,

src/property_attribute.rs

@@ -0,0 +1,94 @@
+#[repr(C)]
+#[derive(Debug, Eq, PartialEq)]
+pub struct PropertyAttribute(u32);
+
+/// No property attributes.
+pub const NONE: PropertyAttribute = PropertyAttribute(0);
+
+/// Not writable. Corresponds to
+/// `Object.defineProperty(o, "p", { writable: false })`.
+pub const READ_ONLY: PropertyAttribute = PropertyAttribute(1);
+
+/// Not enumerable. Corresponds to
+/// `Object.defineProperty(o, "p", { enumerable: false })`.
+pub const DONT_ENUM: PropertyAttribute = PropertyAttribute(2);
+
+/// Not configurable. Corresponds to
+/// `Object.defineProperty(o, "p", { configurable: false })`.
+pub const DONT_DELETE: PropertyAttribute = PropertyAttribute(4);
+
+impl PropertyAttribute {
+  /// Test if no property attributes are set.
+  pub fn is_none(&self) -> bool {
+    *self == NONE
+  }
+
+  /// Test if the read-only property attribute is set.
+  pub fn is_read_only(&self) -> bool {
+    self.has(READ_ONLY)
+  }
+
+  /// Test if the non-enumerable property attribute is set.
+  pub fn is_dont_enum(&self) -> bool {
+    self.has(DONT_ENUM)
+  }
+
+  /// Test if the non-configurable property attribute is set.
+  pub fn is_dont_delete(&self) -> bool {
+    self.has(DONT_DELETE)
+  }
+
+  fn has(&self, that: Self) -> bool {
+    let Self(lhs) = self;
+    let Self(rhs) = that;
+    0 != lhs & rhs
+  }
+}
+
+// Identical to #[derive(Default)] but arguably clearer when made explicit.
+impl Default for PropertyAttribute {
+  fn default() -> Self {
+    NONE
+  }
+}
+
+impl std::ops::Add for PropertyAttribute {
+  type Output = Self;
+
+  fn add(self, Self(rhs): Self) -> Self {
+    let Self(lhs) = self;
+    Self(lhs + rhs)
+  }
+}
+
+#[test]
+fn test_attr() {
+  assert!(NONE.is_none());
+  assert!(!NONE.is_read_only());
+  assert!(!NONE.is_dont_enum());
+  assert!(!NONE.is_dont_delete());
+
+  assert!(!READ_ONLY.is_none());
+  assert!(READ_ONLY.is_read_only());
+  assert!(!READ_ONLY.is_dont_enum());
+  assert!(!READ_ONLY.is_dont_delete());
+
+  assert!(!DONT_ENUM.is_none());
+  assert!(!DONT_ENUM.is_read_only());
+  assert!(DONT_ENUM.is_dont_enum());
+  assert!(!DONT_ENUM.is_dont_delete());
+
+  assert!(!DONT_DELETE.is_none());
+  assert!(!DONT_DELETE.is_read_only());
+  assert!(!DONT_DELETE.is_dont_enum());
+  assert!(DONT_DELETE.is_dont_delete());
+
+  assert_eq!(NONE, Default::default());
+  assert_eq!(READ_ONLY, NONE + READ_ONLY);
+
+  let attr = READ_ONLY + DONT_ENUM;
+  assert!(!attr.is_none());
+  assert!(attr.is_read_only());
+  assert!(attr.is_dont_enum());
+  assert!(!attr.is_dont_delete());
+}

src/template.rs

@@ -10,11 +10,18 @@ use crate::Function;
 use crate::FunctionCallback;
 use crate::Local;
 use crate::Object;
+use crate::PropertyAttribute;
 use crate::String;
 use crate::ToLocal;
+use crate::NONE;
 
 extern "C" {
-  fn v8__Template__Set(self_: &Template, key: *const Name, value: *const Data);
+  fn v8__Template__Set(
+    self_: &Template,
+    key: *const Name,
+    value: *const Data,
+    attr: PropertyAttribute,
+  );
 
   fn v8__FunctionTemplate__New(
     isolate: &Isolate,
@@ -42,8 +49,18 @@ extern "C" {
 impl Template {
   /// Adds a property to each instance created by this template.
   pub fn set(&self, key: Local<Name>, value: Local<Data>) {
-    // TODO(bnoordhuis) Allow setting PropertyAttributes.
-    unsafe { v8__Template__Set(self, &*key, &*value) }
+    self.set_with_attr(key, value, NONE)
+  }
+
+  /// Adds a property to each instance created by this template with
+  /// the specified property attributes.
+  pub fn set_with_attr(
+    &self,
+    key: Local<Name>,
+    value: Local<Data>,
+    attr: PropertyAttribute,
+  ) {
+    unsafe { v8__Template__Set(self, &*key, &*value, attr) }
   }
 }
 

tests/test_api.rs

@@ -869,19 +869,41 @@ fn object_template() {
     let object_templ = v8::ObjectTemplate::new(scope);
     let function_templ = v8::FunctionTemplate::new(scope, fortytwo_callback);
     let name = v8_str(scope, "f");
-    object_templ.set(name.into(), function_templ.into());
+    let attr = v8::READ_ONLY + v8::DONT_ENUM + v8::DONT_DELETE;
+    object_templ.set_with_attr(name.into(), function_templ.into(), attr);
     let context = v8::Context::new(scope);
     let mut cs = v8::ContextScope::new(scope, context);
     let scope = cs.enter();
     let object = object_templ.new_instance(scope, context).unwrap();
     assert!(!object.is_null_or_undefined());
     let name = v8_str(scope, "g");
-    context
-      .global(scope)
-      .set(context, name.into(), object.into());
+    context.global(scope).define_own_property(
+      context,
+      name.into(),
+      object.into(),
+      v8::DONT_ENUM,
+    );
+    let source = r#"
+      {
+        const d = Object.getOwnPropertyDescriptor(globalThis, "g");
+        [d.configurable, d.enumerable, d.writable].toString()
+      }
+    "#;
+    let actual = eval(scope, context, source).unwrap();
+    let expected = v8_str(scope, "true,false,true");
+    assert!(expected.strict_equals(actual));
     let actual = eval(scope, context, "g.f()").unwrap();
     let expected = v8::Integer::new(scope, 42);
     assert!(expected.strict_equals(actual));
+    let source = r#"
+      {
+        const d = Object.getOwnPropertyDescriptor(g, "f");
+        [d.configurable, d.enumerable, d.writable].toString()
+      }
+    "#;
+    let actual = eval(scope, context, source).unwrap();
+    let expected = v8_str(scope, "false,false,false");
+    assert!(expected.strict_equals(actual));
   }
 }