v8binding: Introduce WorldSafeV8Reference class

WorldSafeV8Reference class provides safe access across worlds
plus wrapper-tracing.

The usage is demonstrated at CustomEvent.detail.

Change-Id: I6c640d916063ac87604bd63f25524f8a4f8dd817
Bug: 501866, 755520, 803478
Reviewed-on: https://chromium-review.googlesource.com/c/1358611
Commit-Queue: Yuki Shiino <yukishiino@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: Hitoshi Yoshida <peria@chromium.org>
Cr-Commit-Position: refs/heads/master@{#615844}

third_party/blink/renderer/bindings/bindings.gni

@@ -9,6 +9,12 @@ import("//third_party/blink/renderer/bindings/modules/v8/v8.gni")
 
 bindings_core_v8_files =
     get_path_info([
+                    "core/v8/active_script_wrappable.h",
+                    "core/v8/array_value.cc",
+                    "core/v8/array_value.h",
+                    "core/v8/binding_security.cc",
+                    "core/v8/binding_security.h",
+                    "core/v8/callback_promise_adapter.h",
                     "core/v8/custom/v8_custom_xpath_ns_resolver.cc",
                     "core/v8/custom/v8_custom_xpath_ns_resolver.h",
                     "core/v8/custom/v8_dev_tools_host_custom.cc",
@@ -26,12 +32,6 @@ bindings_core_v8_files =
                     "core/v8/custom/v8_shadow_root_custom.cc",
                     "core/v8/custom/v8_window_custom.cc",
                     "core/v8/custom/v8_xml_http_request_custom.cc",
-                    "core/v8/active_script_wrappable.h",
-                    "core/v8/array_value.cc",
-                    "core/v8/array_value.h",
-                    "core/v8/binding_security.cc",
-                    "core/v8/binding_security.h",
-                    "core/v8/callback_promise_adapter.h",
                     "core/v8/custom_wrappable_adapter.cc",
                     "core/v8/custom_wrappable_adapter.h",
                     "core/v8/dictionary.cc",
@@ -39,19 +39,19 @@ bindings_core_v8_files =
                     "core/v8/dictionary_helper_for_core.cc",
                     "core/v8/generated_code_helper.cc",
                     "core/v8/generated_code_helper.h",
-                    "core/v8/initialize_v8_extras_binding.cc",
-                    "core/v8/initialize_v8_extras_binding.h",
                     "core/v8/idl_dictionary_base.cc",
                     "core/v8/idl_dictionary_base.h",
                     "core/v8/idl_types.h",
                     "core/v8/idl_types_base.h",
+                    "core/v8/initialize_v8_extras_binding.cc",
+                    "core/v8/initialize_v8_extras_binding.h",
                     "core/v8/iterable.h",
                     "core/v8/js_based_event_listener.cc",
                     "core/v8/js_based_event_listener.h",
                     "core/v8/js_event_handler.cc",
                     "core/v8/js_event_handler.h",
-                    "core/v8/js_event_handler_for_content_attribute.h",
                     "core/v8/js_event_handler_for_content_attribute.cc",
+                    "core/v8/js_event_handler_for_content_attribute.h",
                     "core/v8/js_event_listener.cc",
                     "core/v8/js_event_listener.h",
                     "core/v8/local_window_proxy.cc",
@@ -66,6 +66,7 @@ bindings_core_v8_files =
                     "core/v8/remote_window_proxy.cc",
                     "core/v8/remote_window_proxy.h",
                     "core/v8/retained_object_info.h",
+                    "core/v8/sanitize_script_errors.h",
                     "core/v8/scheduled_action.cc",
                     "core/v8/scheduled_action.h",
                     "core/v8/script_controller.cc",
@@ -84,7 +85,6 @@ bindings_core_v8_files =
                     "core/v8/script_iterator.h",
                     "core/v8/script_module.cc",
                     "core/v8/script_module.h",
-                    "core/v8/sanitize_script_errors.h",
                     "core/v8/script_promise.cc",
                     "core/v8/script_promise.h",
                     "core/v8/script_promise_property.h",
@@ -103,6 +103,22 @@ bindings_core_v8_files =
                     "core/v8/script_streamer_thread.h",
                     "core/v8/script_value.cc",
                     "core/v8/script_value.h",
+                    "core/v8/serialization/post_message_helper.cc",
+                    "core/v8/serialization/post_message_helper.h",
+                    "core/v8/serialization/serialization_tag.h",
+                    "core/v8/serialization/serialized_color_params.cc",
+                    "core/v8/serialization/serialized_color_params.h",
+                    "core/v8/serialization/serialized_script_value.cc",
+                    "core/v8/serialization/serialized_script_value.h",
+                    "core/v8/serialization/serialized_script_value_factory.cc",
+                    "core/v8/serialization/serialized_script_value_factory.h",
+                    "core/v8/serialization/transferables.h",
+                    "core/v8/serialization/unpacked_serialized_script_value.cc",
+                    "core/v8/serialization/unpacked_serialized_script_value.h",
+                    "core/v8/serialization/v8_script_value_deserializer.cc",
+                    "core/v8/serialization/v8_script_value_deserializer.h",
+                    "core/v8/serialization/v8_script_value_serializer.cc",
+                    "core/v8/serialization/v8_script_value_serializer.h",
                     "core/v8/source_location.cc",
                     "core/v8/source_location.h",
                     "core/v8/to_v8_for_core.cc",
@@ -116,6 +132,8 @@ bindings_core_v8_files =
                     "core/v8/v8_cache_options.h",
                     "core/v8/v8_code_cache.cc",
                     "core/v8/v8_code_cache.h",
+                    "core/v8/v8_context_snapshot.cc",
+                    "core/v8/v8_context_snapshot.h",
                     "core/v8/v8_dom_configuration.cc",
                     "core/v8/v8_dom_configuration.h",
                     "core/v8/v8_embedder_graph_builder.cc",
@@ -134,8 +152,6 @@ bindings_core_v8_files =
                     "core/v8/v8_initializer.h",
                     "core/v8/v8_intersection_observer_delegate.cc",
                     "core/v8/v8_intersection_observer_delegate.h",
-                    "core/v8/v8_throw_dom_exception.cc",
-                    "core/v8/v8_throw_dom_exception.h",
                     "core/v8/v8_iterator_result_value.cc",
                     "core/v8/v8_iterator_result_value.h",
                     "core/v8/v8_object_builder.cc",
@@ -147,9 +163,9 @@ bindings_core_v8_files =
                     "core/v8/v8_persistent_value_vector.h",
                     "core/v8/v8_script_runner.cc",
                     "core/v8/v8_script_runner.h",
-                    "core/v8/v8_context_snapshot.cc",
-                    "core/v8/v8_context_snapshot.h",
                     "core/v8/v8_string_resource.h",
+                    "core/v8/v8_throw_dom_exception.cc",
+                    "core/v8/v8_throw_dom_exception.h",
                     "core/v8/v8_v0_custom_element_lifecycle_callbacks.cc",
                     "core/v8/v8_v0_custom_element_lifecycle_callbacks.h",
                     "core/v8/v8_wasm_response_extensions.cc",
@@ -160,22 +176,8 @@ bindings_core_v8_files =
                     "core/v8/window_proxy_manager.h",
                     "core/v8/worker_or_worklet_script_controller.cc",
                     "core/v8/worker_or_worklet_script_controller.h",
-                    "core/v8/serialization/post_message_helper.cc",
-                    "core/v8/serialization/post_message_helper.h",
-                    "core/v8/serialization/serialized_color_params.cc",
-                    "core/v8/serialization/serialized_color_params.h",
-                    "core/v8/serialization/serialization_tag.h",
-                    "core/v8/serialization/serialized_script_value.cc",
-                    "core/v8/serialization/serialized_script_value.h",
-                    "core/v8/serialization/serialized_script_value_factory.cc",
-                    "core/v8/serialization/serialized_script_value_factory.h",
-                    "core/v8/serialization/transferables.h",
-                    "core/v8/serialization/unpacked_serialized_script_value.cc",
-                    "core/v8/serialization/unpacked_serialized_script_value.h",
-                    "core/v8/serialization/v8_script_value_deserializer.cc",
-                    "core/v8/serialization/v8_script_value_deserializer.h",
-                    "core/v8/serialization/v8_script_value_serializer.cc",
-                    "core/v8/serialization/v8_script_value_serializer.h",
+                    "core/v8/world_safe_v8_reference.cc",
+                    "core/v8/world_safe_v8_reference.h",
                   ],
                   "abspath")
 

third_party/blink/renderer/bindings/core/v8/world_safe_v8_reference.cc

+// Copyright 2018 The Chromium 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 "third_party/blink/renderer/bindings/core/v8/world_safe_v8_reference.h"
+
+#include "third_party/blink/renderer/bindings/core/v8/serialization/serialized_script_value.h"
+#include "third_party/blink/renderer/platform/bindings/script_state.h"
+
+namespace blink {
+
+// static
+v8::Local<v8::Value> WorldSafeV8ReferenceInternal::ToWorldSafeValue(
+    ScriptState* target_script_state,
+    const TraceWrapperV8Reference<v8::Value>& v8_reference,
+    const DOMWrapperWorld& v8_reference_world) {
+  DCHECK(!v8_reference.IsEmpty());
+
+  v8::Isolate* isolate = target_script_state->GetIsolate();
+
+  if (&v8_reference_world == &target_script_state->World())
+    return v8_reference.NewLocal(isolate);
+
+  // If |v8_reference| is a v8::Object, clones |v8_reference| in the context of
+  // |target_script_state| and returns it.  Otherwise returns |v8_reference|
+  // itself that is already safe to access in |target_script_state|.
+
+  v8::Local<v8::Value> value = v8_reference.NewLocal(isolate);
+  if (!value->IsObject())
+    return value;
+
+  v8::Context::Scope target_context_scope(target_script_state->GetContext());
+  return SerializedScriptValue::SerializeAndSwallowExceptions(isolate, value)
+      ->Deserialize(isolate);
+}
+
+// static
+void WorldSafeV8ReferenceInternal::MaybeCheckCreationContextWorld(
+    const DOMWrapperWorld& world,
+    v8::Local<v8::Value> value) {
+  if (!value->IsObject())
+    return;
+
+  ScriptState* script_state =
+      ScriptState::From(value.As<v8::Object>()->CreationContext());
+  CHECK_EQ(&world, &script_state->World());
+}
+
+}  // namespace blink

third_party/blink/renderer/bindings/core/v8/world_safe_v8_reference.h

+// Copyright 2018 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef THIRD_PARTY_BLINK_RENDERER_BINDINGS_CORE_V8_WORLD_SAFE_V8_REFERENCE_H_
+#define THIRD_PARTY_BLINK_RENDERER_BINDINGS_CORE_V8_WORLD_SAFE_V8_REFERENCE_H_
+
+#include "third_party/blink/renderer/platform/bindings/dom_wrapper_world.h"
+#include "third_party/blink/renderer/platform/bindings/trace_wrapper_v8_reference.h"
+#include "third_party/blink/renderer/platform/heap/handle.h"
+#include "v8/include/v8.h"
+
+namespace blink {
+
+class ScriptState;
+
+// This is a namespace to provide utility functions to WorldSafeV8Reference.
+class WorldSafeV8ReferenceInternal final {
+  STATIC_ONLY(WorldSafeV8ReferenceInternal);
+
+ private:
+  // Returns a V8 reference that is safe to access in |target_script_state|.
+  // The return value may be a cloned object.
+  //
+  // TODO(crbug.com/803478): ScriptValue::V8ValueFor should be replaced with
+  // this function, or these two functions should be merged at least.
+  static v8::Local<v8::Value> ToWorldSafeValue(
+      ScriptState* target_script_state,
+      const TraceWrapperV8Reference<v8::Value>& v8_reference,
+      const DOMWrapperWorld& v8_reference_world);
+
+  // Checks the world of |value|'s creation context if |value| is a v8::Object.
+  // The given |world| and |value|'s world must match.  Otherwise, crashes.
+  //
+  // TODO(yukishiino): Find the best place to put this function.  We might want
+  // to share this function among other clients, e.g. access to wrapper objects
+  // across worlds.
+  static void MaybeCheckCreationContextWorld(const DOMWrapperWorld& world,
+                                             v8::Local<v8::Value> value);
+
+  template <typename V8Type>
+  friend class WorldSafeV8Reference;
+};
+
+// This class provides safe access to v8::Value across worlds.  This class
+// provides accessors that check whether the value is accessed in the same world
+// or not, also provides an accessor that clones the value when accessed across
+// worlds.
+template <typename V8Type>
+class WorldSafeV8Reference final {
+  DISALLOW_NEW();
+
+ public:
+  WorldSafeV8Reference() = default;
+  explicit WorldSafeV8Reference(v8::Isolate* isolate, v8::Local<V8Type> value)
+      : v8_reference_(isolate, value),
+        world_(&DOMWrapperWorld::Current(isolate)) {
+    MaybeCheckCreationContextWorld(*world_.get(), value);
+  }
+  ~WorldSafeV8Reference() = default;
+
+  // Returns the V8 reference.  Crashes if |target_script_state|'s world is
+  // different from this V8 reference's world.
+  v8::Local<V8Type> Get(ScriptState* target_script_state) const {
+    DCHECK(!v8_reference_.IsEmpty());
+    CHECK_EQ(world_.get(), &target_script_state->World());
+    return v8_reference_.NewLocal(target_script_state->GetIsolate());
+  }
+
+  // Returns a V8 reference that is safe to access in |target_script_state|.
+  // The return value may be a cloned object.
+  v8::Local<V8Type> GetAcrossWorld(ScriptState* target_script_state) const {
+    return WorldSafeV8ReferenceInternal::ToWorldSafeValue(
+               target_script_state, v8_reference_, *world_.get())
+        .template As<V8Type>();
+  }
+
+  // Sets a new V8 reference.  Crashes if |new_value|'s world is different from
+  // this V8 reference's world.
+  void Set(v8::Isolate* isolate, v8::Local<V8Type> new_value) {
+    DCHECK(!new_value.IsEmpty());
+    const DOMWrapperWorld& new_world = DOMWrapperWorld::Current(isolate);
+    MaybeCheckCreationContextWorld(new_world, new_value);
+    CHECK(v8_reference_.IsEmpty() || world_.get() == &new_world);
+    v8_reference_.Set(isolate, new_value);
+    world_ = WrapRefCounted(&new_world);
+  }
+
+  // Forcibly sets a new V8 reference even when the worlds are different.  The
+  // world of this V8 reference will be |new_value|'s world.
+  void SetAcrossWorld(v8::Isolate* isolate, v8::Local<V8Type> new_value) {
+    DCHECK(!new_value.IsEmpty());
+    const DOMWrapperWorld& new_world = DOMWrapperWorld::Current(isolate);
+    v8_reference_.Set(isolate, new_value);
+    world_ = WrapRefCounted(&new_world);
+  }
+
+  void Reset() {
+    v8_reference_.Clear();
+    world_.reset();
+  }
+
+  bool IsEmpty() const { return v8_reference_.IsEmpty(); }
+
+  void Trace(blink::Visitor* visitor) { visitor->Trace(v8_reference_); }
+
+ private:
+  TraceWrapperV8Reference<V8Type> v8_reference_;
+  // The world of the current context at the time when |v8_reference_| was set.
+  // It's guaranteed that, if |v8_reference_| is a v8::Object, the world of the
+  // creation context of |v8_reference_| is the same as |world_|.
+  scoped_refptr<const DOMWrapperWorld> world_;
+
+  DISALLOW_COPY_AND_ASSIGN(WorldSafeV8Reference);
+};
+
+}  // namespace blink
+
+#endif  // THIRD_PARTY_BLINK_RENDERER_BINDINGS_CORE_V8_WORLD_SAFE_V8_REFERENCE_H_

third_party/blink/renderer/core/dom/events/custom_event.cc

@@ -25,8 +25,6 @@
 
 #include "third_party/blink/renderer/core/dom/events/custom_event.h"
 
-#include "third_party/blink/renderer/bindings/core/v8/serialization/serialized_script_value.h"
-#include "third_party/blink/renderer/bindings/core/v8/serialization/serialized_script_value_factory.h"
 #include "third_party/blink/renderer/core/event_interface_names.h"
 
 namespace blink {
@@ -37,10 +35,9 @@ CustomEvent::CustomEvent(ScriptState* script_state,
                          const AtomicString& type,
                          const CustomEventInit* initializer)
     : Event(type, initializer) {
-  world_ = WrapRefCounted(&script_state->World());
   if (initializer->hasDetail()) {
-    detail_.Set(initializer->detail().GetIsolate(),
-                initializer->detail().V8Value());
+    detail_.SetAcrossWorld(initializer->detail().GetIsolate(),
+                           initializer->detail().V8Value());
   }
 }
 
@@ -52,23 +49,15 @@ void CustomEvent::initCustomEvent(ScriptState* script_state,
                                   bool cancelable,
                                   const ScriptValue& script_value) {
   initEvent(type, bubbles, cancelable);
-  world_ = WrapRefCounted(&script_state->World());
   if (!IsBeingDispatched() && !script_value.IsEmpty())
-    detail_.Set(script_value.GetIsolate(), script_value.V8Value());
+    detail_.SetAcrossWorld(script_value.GetIsolate(), script_value.V8Value());
 }
 
 ScriptValue CustomEvent::detail(ScriptState* script_state) const {
   v8::Isolate* isolate = script_state->GetIsolate();
   if (detail_.IsEmpty())
     return ScriptValue(script_state, v8::Null(isolate));
-  // Returns a clone of |detail_| if the world is different.
-  if (!world_ || world_->GetWorldId() != script_state->World().GetWorldId()) {
-    v8::Local<v8::Value> value = detail_.NewLocal(isolate);
-    scoped_refptr<SerializedScriptValue> serialized =
-        SerializedScriptValue::SerializeAndSwallowExceptions(isolate, value);
-    return ScriptValue(script_state, serialized->Deserialize(isolate));
-  }
-  return ScriptValue(script_state, detail_.NewLocal(isolate));
+  return ScriptValue(script_state, detail_.GetAcrossWorld(script_state));
 }
 
 const AtomicString& CustomEvent::InterfaceName() const {

third_party/blink/renderer/core/dom/events/custom_event.h

@@ -26,11 +26,10 @@
 #ifndef THIRD_PARTY_BLINK_RENDERER_CORE_DOM_EVENTS_CUSTOM_EVENT_H_
 #define THIRD_PARTY_BLINK_RENDERER_CORE_DOM_EVENTS_CUSTOM_EVENT_H_
 
+#include "third_party/blink/renderer/bindings/core/v8/world_safe_v8_reference.h"
 #include "third_party/blink/renderer/core/core_export.h"
 #include "third_party/blink/renderer/core/dom/events/custom_event_init.h"
 #include "third_party/blink/renderer/core/dom/events/event.h"
-#include "third_party/blink/renderer/platform/bindings/dom_wrapper_world.h"
-#include "third_party/blink/renderer/platform/bindings/trace_wrapper_v8_reference.h"
 
 namespace blink {
 
@@ -66,8 +65,7 @@ class CORE_EXPORT CustomEvent final : public Event {
   void Trace(blink::Visitor*) override;
 
  private:
-  scoped_refptr<DOMWrapperWorld> world_;
-  TraceWrapperV8Reference<v8::Value> detail_;
+  WorldSafeV8Reference<v8::Value> detail_;
 };
 
 }  // namespace blink