[api] Add PropertyDescriptor and DefineProperty().

test/cctest/test-api.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 15986 matching lines @@
       templ->NewInstance(env.local()).ToLocalChecked();
   {
     v8::TryCatch try_catch(isolate);
     CHECK(access_checked->DefineOwnProperty(env.local(), v8_str("foo"),
                                             v8::Integer::New(isolate, 42))
               .IsNothing());
     CHECK(try_catch.HasCaught());
   }
 }
 
+TEST(DefineProperty) {
+  LocalContext env;
+  v8::Isolate* isolate = env->GetIsolate();
+  v8::HandleScope handle_scope(isolate);
+
+  v8::Local<v8::Name> p;
+
+  CompileRun(
+      "var a = {};"
+      "var b = [];"
+      "Object.defineProperty(a, 'v1', {value: 23});"
+      "Object.defineProperty(a, 'v2', {value: 23, configurable: true});");
+
+  v8::Local<v8::Object> obj = v8::Local<v8::Object>::Cast(
+      env->Global()->Get(env.local(), v8_str("a")).ToLocalChecked());
+  v8::Local<v8::Array> arr = v8::Local<v8::Array>::Cast(
+      env->Global()->Get(env.local(), v8_str("b")).ToLocalChecked());
+
+  const v8::PropertyDescriptor desc(v8_num(42));
+  {
+    // Use a data descriptor.
+
+    // Cannot change a non-configurable property.
+    p = v8_str("v1");
+    v8::TryCatch try_catch(isolate);
+    CHECK(!obj->DefineProperty(env.local(), p, desc).FromJust());
+    CHECK(!try_catch.HasCaught());
+    v8::Local<v8::Value> val = obj->Get(env.local(), p).ToLocalChecked();
+    CHECK(val->IsNumber());
+    CHECK_EQ(23.0, val->NumberValue(env.local()).FromJust());
+
+    // Change a configurable property.
+    p = v8_str("v2");
+    CHECK(obj->DefineProperty(env.local(), p, desc).FromJust());
+    CHECK(!try_catch.HasCaught());
+    val = obj->Get(env.local(), p).ToLocalChecked();
+    CHECK(val->IsNumber());
+    CHECK_EQ(42.0, val->NumberValue(env.local()).FromJust());
+  }
+
+  {
+    // Set a regular property.
+    p = v8_str("v3");
+    v8::TryCatch try_catch(isolate);
+    CHECK(obj->DefineProperty(env.local(), p, desc).FromJust());
+    CHECK(!try_catch.HasCaught());
+    v8::Local<v8::Value> val = obj->Get(env.local(), p).ToLocalChecked();
+    CHECK(val->IsNumber());
+    CHECK_EQ(42.0, val->NumberValue(env.local()).FromJust());
+  }
+
+  {
+    // Set an indexed property.
+    v8::TryCatch try_catch(isolate);
+    CHECK(obj->DefineProperty(env.local(), v8_str("1"), desc).FromJust());
+    CHECK(!try_catch.HasCaught());
+    v8::Local<v8::Value> val = obj->Get(env.local(), 1).ToLocalChecked();
+    CHECK(val->IsNumber());
+    CHECK_EQ(42.0, val->NumberValue(env.local()).FromJust());
+  }
+
+  {
+    // No special case when changing array length.
+    v8::TryCatch try_catch(isolate);
+    CHECK(arr->DefineProperty(env.local(), v8_str("length"), desc).FromJust());
+    CHECK(!try_catch.HasCaught());
+  }
+
+  {
+    // Special cases for arrays: index exceeds the array's length.
+    v8::TryCatch try_catch(isolate);
+    CHECK(arr->DefineProperty(env.local(), v8_str("100"), desc).FromJust());
+    CHECK(!try_catch.HasCaught());
+    CHECK_EQ(101U, arr->Length());
+    v8::Local<v8::Value> val = arr->Get(env.local(), 100).ToLocalChecked();
+    CHECK(val->IsNumber());
+    CHECK_EQ(42.0, val->NumberValue(env.local()).FromJust());
+
+    // Set an existing entry.
+    CHECK(arr->DefineProperty(env.local(), v8_str("0"), desc).FromJust());
+    CHECK(!try_catch.HasCaught());
+    val = arr->Get(env.local(), 0).ToLocalChecked();
+    CHECK(val->IsNumber());
+    CHECK_EQ(42.0, val->NumberValue(env.local()).FromJust());
+  }
+
+  {
+    // Use a generic descriptor.
+    const v8::PropertyDescriptor desc_generic;
+
+    p = v8_str("v4");
+    v8::TryCatch try_catch(isolate);
+    CHECK(obj->DefineProperty(env.local(), p, desc_generic).FromJust());
+    CHECK(!try_catch.HasCaught());
+    v8::Local<v8::Value> val = obj->Get(env.local(), p).ToLocalChecked();
+    CHECK(val->IsUndefined());
+
+    obj->Set(env.local(), p, v8_num(1)).FromJust();
+    CHECK(!try_catch.HasCaught());
+
+    val = obj->Get(env.local(), p).ToLocalChecked();
+    CHECK(val->IsUndefined());
+    CHECK(!try_catch.HasCaught());
+  }
+
+  {
+    // Use a data descriptor with undefined value.
+    const v8::PropertyDescriptor desc_empty(v8::Undefined(isolate));
+
+    v8::TryCatch try_catch(isolate);
+    CHECK(obj->DefineProperty(env.local(), p, desc_empty).FromJust());
+    CHECK(!try_catch.HasCaught());
+    v8::Local<v8::Value> val = obj->Get(env.local(), p).ToLocalChecked();
+    CHECK(val->IsUndefined());
+    CHECK(!try_catch.HasCaught());
+  }
+
+  {
+    // Use a descriptor with attribute == v8::ReadOnly.
+    v8::PropertyDescriptor desc_read_only(v8_num(42), false);
+    desc_read_only.set_enumerable(true);
+    desc_read_only.set_configurable(true);
+
+    p = v8_str("v5");
+    v8::TryCatch try_catch(isolate);
+    CHECK(obj->DefineProperty(env.local(), p, desc_read_only).FromJust());
+    CHECK(!try_catch.HasCaught());
+    v8::Local<v8::Value> val = obj->Get(env.local(), p).ToLocalChecked();
+    CHECK(val->IsNumber());
+    CHECK_EQ(42.0, val->NumberValue(env.local()).FromJust());
+    CHECK_EQ(v8::ReadOnly,
+             obj->GetPropertyAttributes(env.local(), p).FromJust());
+    CHECK(!try_catch.HasCaught());
+  }
+
+  {
+    // Use an accessor descriptor with empty handles.
+    const v8::PropertyDescriptor desc_empty(v8::Undefined(isolate),
+                                            v8::Undefined(isolate));
+
+    p = v8_str("v6");
+    v8::TryCatch try_catch(isolate);
+    CHECK(obj->DefineProperty(env.local(), p, desc_empty).FromJust());
+    CHECK(!try_catch.HasCaught());
+    v8::Local<v8::Value> val = obj->Get(env.local(), p).ToLocalChecked();
+    CHECK(val->IsUndefined());
+    CHECK(!try_catch.HasCaught());
+  }
+
+  {
+    // Use an accessor descriptor.
+    CompileRun(
+        "var set = function(x) {this.val = 2*x;};"
+        "var get = function() {return this.val || 0;};");
+
+    v8::Local<v8::Function> get = v8::Local<v8::Function>::Cast(
+        env->Global()->Get(env.local(), v8_str("get")).ToLocalChecked());
+    v8::Local<v8::Function> set = v8::Local<v8::Function>::Cast(
+        env->Global()->Get(env.local(), v8_str("set")).ToLocalChecked());
+    const v8::PropertyDescriptor desc(get, set);
+
+    p = v8_str("v7");
+    v8::TryCatch try_catch(isolate);
+    CHECK(obj->DefineProperty(env.local(), p, desc).FromJust());
+    CHECK(!try_catch.HasCaught());
+
+    v8::Local<v8::Value> val = obj->Get(env.local(), p).ToLocalChecked();
+    CHECK(val->IsNumber());
+    CHECK_EQ(0.0, val->NumberValue(env.local()).FromJust());
+    CHECK(!try_catch.HasCaught());
+
+    obj->Set(env.local(), p, v8_num(7)).FromJust();
+    CHECK(!try_catch.HasCaught());
+
+    val = obj->Get(env.local(), p).ToLocalChecked();
+    CHECK(val->IsNumber());
+    CHECK_EQ(14.0, val->NumberValue(env.local()).FromJust());
+    CHECK(!try_catch.HasCaught());
+  }
+
+  {
+    // Redefine an existing property.
+
+    // desc = {value: 42, enumerable: true}
+    v8::PropertyDescriptor desc(v8_num(42));
+    desc.set_enumerable(true);
+
+    p = v8_str("v8");
+    v8::TryCatch try_catch(isolate);
+    CHECK(obj->DefineProperty(env.local(), p, desc).FromJust());
+    CHECK(!try_catch.HasCaught());
+
+    // desc = {enumerable: true}
+    v8::PropertyDescriptor desc_true((v8::Local<v8::Value>()));
+    desc_true.set_enumerable(true);
+
+    // Successful redefinition because all present attributes have the same
+    // value as the current descriptor.
+    CHECK(obj->DefineProperty(env.local(), p, desc_true).FromJust());
+    CHECK(!try_catch.HasCaught());
+
+    // desc = {}
+    const v8::PropertyDescriptor desc_empty;
+    // Successful redefinition because no attributes are overwritten in the
+    // current descriptor.
+    CHECK(obj->DefineProperty(env.local(), p, desc_empty).FromJust());
+    CHECK(!try_catch.HasCaught());
+
+    // desc = {enumerable: false}
+    v8::PropertyDescriptor desc_false((v8::Local<v8::Value>()));
+    desc_false.set_enumerable(false);
+    // Not successful because we cannot define a different value for enumerable.
+    CHECK(!obj->DefineProperty(env.local(), p, desc_false).FromJust());
+    CHECK(!try_catch.HasCaught());
+  }
+
+  {
+    // Redefine a property that has a getter.
+    CompileRun("var get = function() {};");
+    v8::Local<v8::Function> get = v8::Local<v8::Function>::Cast(
+        env->Global()->Get(env.local(), v8_str("get")).ToLocalChecked());
+
+    // desc = {get: function() {}}
+    const v8::PropertyDescriptor desc(get, v8::Local<v8::Function>());
+    v8::TryCatch try_catch(isolate);
+
+    p = v8_str("v9");
+    CHECK(obj->DefineProperty(env.local(), p, desc).FromJust());
+    CHECK(!try_catch.HasCaught());
+
+    // desc_empty = {}
+    // Successful because we are not redefining the current getter.
+    const v8::PropertyDescriptor desc_empty;
+    CHECK(obj->DefineProperty(env.local(), p, desc_empty).FromJust());
+    CHECK(!try_catch.HasCaught());
+
+    // desc = {get: function() {}}
+    // Successful because we redefine the getter with its current value.
+    CHECK(obj->DefineProperty(env.local(), p, desc).FromJust());
+    CHECK(!try_catch.HasCaught());
+
+    // desc = {get: undefined}
+    const v8::PropertyDescriptor desc_undefined(v8::Undefined(isolate),
+                                                v8::Local<v8::Function>());
+    // Not successful because we cannot redefine with the current value of get
+    // with undefined.
+    CHECK(!obj->DefineProperty(env.local(), p, desc_undefined).FromJust());
+    CHECK(!try_catch.HasCaught());
+  }
+
+  CompileRun("Object.freeze(a);");
+  {
+    // We cannot change non-extensible objects.
+    v8::TryCatch try_catch(isolate);
+    CHECK(!obj->DefineProperty(env.local(), v8_str("v10"), desc).FromJust());
+    CHECK(!try_catch.HasCaught());
+  }
+
+  v8::Local<v8::ObjectTemplate> templ = v8::ObjectTemplate::New(isolate);
+  templ->SetAccessCheckCallback(AccessAlwaysBlocked);
+  v8::Local<v8::Object> access_checked =
+      templ->NewInstance(env.local()).ToLocalChecked();
+  {
+    v8::TryCatch try_catch(isolate);
+    CHECK(access_checked->DefineProperty(env.local(), v8_str("v11"), desc)
+              .IsNothing());
+    CHECK(try_catch.HasCaught());
+  }
+}
 
 THREADED_TEST(GetCurrentContextWhenNotInContext) {
   i::Isolate* isolate = CcTest::i_isolate();
   CHECK(isolate != NULL);
   CHECK(isolate->context() == NULL);
   v8::Isolate* v8_isolate = reinterpret_cast<v8::Isolate*>(isolate);
   v8::HandleScope scope(v8_isolate);
   // The following should not crash, but return an empty handle.
   v8::Local<v8::Context> current = v8_isolate->GetCurrentContext();
   CHECK(current.IsEmpty());
@@ skipping 7315 matching lines @@
       "V8.Test", 0, 10000, v8::internal::HistogramTimer::MILLISECOND, 50,
       reinterpret_cast<v8::internal::Isolate*>(isolate));
   histogramTimer.Start();
   CHECK_EQ(0, strcmp("V8.Test", last_event_message));
   CHECK_EQ(0, last_event_status);
   histogramTimer.Stop();
   CHECK_EQ(0, strcmp("V8.Test", last_event_message));
   CHECK_EQ(1, last_event_status);
 }
 
+TEST(PropertyDescriptor) {

[Jakob Kummerow, 2016/08/31 14:15:13]

I still think that unit tests for getters and setters are so trivial as to be
pointless; but I'm okay with keeping them if you like them.

[Franzi, 2016/08/31 20:10:51]

I like them. They catch some set/get typos or autocompletion errors. 

+  LocalContext context;
+  v8::Isolate* isolate = context->GetIsolate();
+  v8::HandleScope scope(isolate);
+
+  {  // empty descriptor
+    v8::PropertyDescriptor desc;
+    CHECK(!desc.has_value());
+    CHECK(!desc.has_set());
+    CHECK(!desc.has_get());
+    CHECK(!desc.has_enumerable());
+    CHECK(!desc.has_configurable());
+    CHECK(!desc.has_writable());
+  }
+  {
+    // data descriptor
+    v8::PropertyDescriptor desc(v8_num(42));
+    desc.set_enumerable(false);
+    CHECK(desc.value() == v8_num(42));
+    CHECK(desc.has_value());
+    CHECK(!desc.has_set());
+    CHECK(!desc.has_get());
+    CHECK(desc.has_enumerable());
+    CHECK(!desc.enumerable());
+    CHECK(!desc.has_configurable());
+    CHECK(!desc.has_writable());
+  }
+  {
+    // data descriptor
+    v8::PropertyDescriptor desc(v8_num(42));
+    desc.set_configurable(true);
+    CHECK(desc.value() == v8_num(42));
+    CHECK(desc.has_value());
+    CHECK(!desc.has_set());
+    CHECK(!desc.has_get());
+    CHECK(desc.has_configurable());
+    CHECK(desc.configurable());
+    CHECK(!desc.has_enumerable());
+    CHECK(!desc.has_writable());
+  }
+  {
+    // data descriptor
+    v8::PropertyDescriptor desc(v8_num(42));
+    desc.set_configurable(false);
+    CHECK(desc.value() == v8_num(42));
+    CHECK(desc.has_value());
+    CHECK(!desc.has_set());
+    CHECK(!desc.has_get());
+    CHECK(desc.has_configurable());
+    CHECK(!desc.configurable());
+    CHECK(!desc.has_enumerable());
+    CHECK(!desc.has_writable());
+  }
+  {
+    // data descriptor
+    v8::PropertyDescriptor desc(v8_num(42), false);
+    CHECK(desc.value() == v8_num(42));
+    CHECK(desc.has_value());
+    CHECK(!desc.has_set());
+    CHECK(!desc.has_get());
+    CHECK(!desc.has_enumerable());
+    CHECK(!desc.has_configurable());
+    CHECK(desc.has_writable());
+    CHECK(!desc.writable());
+  }
+  {
+    // data descriptor
+    v8::PropertyDescriptor desc(v8::Local<v8::Value>(), true);
+    CHECK(!desc.has_value());
+    CHECK(!desc.has_set());
+    CHECK(!desc.has_get());
+    CHECK(!desc.has_enumerable());
+    CHECK(!desc.has_configurable());
+    CHECK(desc.has_writable());
+    CHECK(desc.writable());
+  }
+  {
+    // accessor descriptor
+    CompileRun("var set = function() {return 43;};");
+
+    v8::Local<v8::Function> set =
+        v8::Local<v8::Function>::Cast(context->Global()
+                                          ->Get(context.local(), v8_str("set"))
+                                          .ToLocalChecked());
+    v8::PropertyDescriptor desc(v8::Undefined(isolate), set);
+    desc.set_configurable(false);
+    CHECK(!desc.has_value());
+    CHECK(desc.has_get());
+    CHECK(desc.get() == v8::Undefined(isolate));
+    CHECK(desc.has_set());
+    CHECK(desc.set() == set);
+    CHECK(!desc.has_enumerable());
+    CHECK(desc.has_configurable());
+    CHECK(!desc.configurable());
+    CHECK(!desc.has_writable());
+  }
+  {
+    // accessor descriptor with Proxy
+    CompileRun(
+        "var set = new Proxy(function() {}, {});"
+        "var get = undefined;");
+
+    v8::Local<v8::Value> get =
+        v8::Local<v8::Value>::Cast(context->Global()
+                                       ->Get(context.local(), v8_str("get"))
+                                       .ToLocalChecked());
+    v8::Local<v8::Function> set =
+        v8::Local<v8::Function>::Cast(context->Global()
+                                          ->Get(context.local(), v8_str("set"))
+                                          .ToLocalChecked());
+    v8::PropertyDescriptor desc(get, set);
+    desc.set_configurable(false);
+    CHECK(!desc.has_value());
+    CHECK(desc.get() == v8::Undefined(isolate));
+    CHECK(desc.has_get());
+    CHECK(desc.set() == set);
+    CHECK(desc.has_set());
+    CHECK(!desc.has_enumerable());
+    CHECK(desc.has_configurable());
+    CHECK(!desc.configurable());
+    CHECK(!desc.has_writable());
+  }
+  {
+    // accessor descriptor with empty function handle
+    v8::Local<v8::Function> get = v8::Local<v8::Function>();
+    v8::PropertyDescriptor desc(get, get);
+    CHECK(!desc.has_value());
+    CHECK(!desc.has_get());
+    CHECK(!desc.has_set());
+    CHECK(!desc.has_enumerable());
+    CHECK(!desc.has_configurable());
+    CHECK(!desc.has_writable());
+  }
+}
 
 TEST(Promises) {
   LocalContext context;
   v8::Isolate* isolate = context->GetIsolate();
   v8::HandleScope scope(isolate);
 
   // Creation.
   Local<v8::Promise::Resolver> pr =
       v8::Promise::Resolver::New(context.local()).ToLocalChecked();
   Local<v8::Promise::Resolver> rr =
@@ skipping 2172 matching lines @@
 
   // Put the function into context1 and call it. Since the access check
   // callback always returns true, the call succeeds even though the tokens
   // are different.
   context1->Enter();
   context1->Global()->Set(context1, v8_str("fun"), fun).FromJust();
   v8::Local<v8::Value> x_value = CompileRun("fun('x')");
   CHECK_EQ(42, x_value->Int32Value(context1).FromJust());
   context1->Exit();
 }