[api] Add documentation for PropertyQueryCallback.

test/cctest/test-api-interceptors.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <stdlib.h>
 
 #include "test/cctest/test-api.h"
 
 #include "include/v8-util.h"
 #include "src/api.h"
@@ skipping 328 matching lines @@
 }
 
 void InterceptorHasOwnPropertyGetterGC(
     Local<Name> name, const v8::PropertyCallbackInfo<v8::Value>& info) {
   ApiTestFuzzer::Fuzz();
   CcTest::heap()->CollectAllGarbage();
 }
 
 }  // namespace
 
+int query_counter_int = 0;
+
+namespace {
+void QueryCallback(Local<Name> property,
+                   const v8::PropertyCallbackInfo<v8::Integer>& info) {
+  query_counter_int++;
+}
+
+}  // namespace
+
+// Examples that show when the query callback is triggered.
+THREADED_TEST(QueryInterceptor) {
+  v8::HandleScope scope(CcTest::isolate());
+  v8::Local<v8::FunctionTemplate> templ =
+      v8::FunctionTemplate::New(CcTest::isolate());
+  templ->InstanceTemplate()->SetHandler(
+      v8::NamedPropertyHandlerConfiguration(0, 0, QueryCallback));
+  LocalContext env;
+  env->Global()
+      ->Set(env.local(), v8_str("obj"), templ->GetFunction(env.local())
+                                            .ToLocalChecked()
+                                            ->NewInstance(env.local())
+                                            .ToLocalChecked())
+      .FromJust();
+  CHECK_EQ(query_counter_int, 0);
+  v8::Local<Value> result =
+      v8_compile("Object.getOwnPropertyDescriptor(obj, 'x');")
+          ->Run(env.local())
+          .ToLocalChecked();
+  CHECK_EQ(query_counter_int, 1);
+  CHECK_EQ(v8::PropertyAttribute::None,
+           static_cast<v8::PropertyAttribute>(
+               result->Int32Value(env.local()).FromJust()));
+
+  v8_compile("Object.defineProperty(obj, 'not_enum', {value: 17});")
+      ->Run(env.local())
+      .ToLocalChecked();
+  CHECK_EQ(query_counter_int, 2);
+
+  v8_compile(
+      "Object.defineProperty(obj, 'enum', {value: 17, enumerable: true, "
+      "writable: true});")
+      ->Run(env.local())
+      .ToLocalChecked();
+  CHECK_EQ(query_counter_int, 3);
+
+  CHECK(v8_compile("obj.propertyIsEnumerable('enum');")
+            ->Run(env.local())
+            .ToLocalChecked()
+            ->BooleanValue(env.local())
+            .FromJust());
+  CHECK_EQ(query_counter_int, 4);
+
+  CHECK(!v8_compile("obj.propertyIsEnumerable('not_enum');")
+             ->Run(env.local())
+             .ToLocalChecked()
+             ->BooleanValue(env.local())
+             .FromJust());
+  CHECK_EQ(query_counter_int, 5);
+
+  CHECK(v8_compile("obj.hasOwnProperty('enum');")
+            ->Run(env.local())
+            .ToLocalChecked()
+            ->BooleanValue(env.local())
+            .FromJust());
+  CHECK_EQ(query_counter_int, 5);
+
+  CHECK(v8_compile("obj.hasOwnProperty('not_enum');")
+            ->Run(env.local())
+            .ToLocalChecked()
+            ->BooleanValue(env.local())
+            .FromJust());
+  CHECK_EQ(query_counter_int, 5);
+
+  CHECK(!v8_compile("obj.hasOwnProperty('x');")
+             ->Run(env.local())
+             .ToLocalChecked()
+             ->BooleanValue(env.local())
+             .FromJust());
+  CHECK_EQ(query_counter_int, 6);
+
+  CHECK(!v8_compile("obj.propertyIsEnumerable('undef');")
+             ->Run(env.local())
+             .ToLocalChecked()
+             ->BooleanValue(env.local())
+             .FromJust());
+  CHECK_EQ(query_counter_int, 7);
+
+  v8_compile("Object.defineProperty(obj, 'enum', {value: 42});")
+      ->Run(env.local())
+      .ToLocalChecked();
+  CHECK_EQ(query_counter_int, 8);
+
+  v8_compile("Object.isFrozen('obj.x');")->Run(env.local()).ToLocalChecked();
+  CHECK_EQ(query_counter_int, 8);
+}
 
 THREADED_TEST(InterceptorHasOwnProperty) {
   LocalContext context;
   v8::Isolate* isolate = context->GetIsolate();
   v8::HandleScope scope(isolate);
   Local<v8::FunctionTemplate> fun_templ = v8::FunctionTemplate::New(isolate);
   Local<v8::ObjectTemplate> instance_templ = fun_templ->InstanceTemplate();
   instance_templ->SetHandler(
       v8::NamedPropertyHandlerConfiguration(InterceptorHasOwnPropertyGetter));
   Local<Function> function =
@@ skipping 3626 matching lines @@
             ->Set(env.local(), v8_str("Fun"),
                   fun_templ->GetFunction(env.local()).ToLocalChecked())
             .FromJust());
 
   CompileRun(
       "var f = new Fun();"
       "Number.prototype.__proto__ = f;"
       "var a = 42;"
       "for (var i = 0; i<3; i++) { a.foo; }");
 }