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- // Copyright 2016 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 "extensions/renderer/bindings/api_event_handler.h"
- #include <algorithm>
- #include <map>
- #include <memory>
- #include <utility>
- #include <vector>
- #include "base/bind.h"
- #include "base/callback_helpers.h"
- #include "base/check.h"
- #include "base/notreached.h"
- #include "base/supports_user_data.h"
- #include "base/values.h"
- #include "content/public/renderer/v8_value_converter.h"
- #include "extensions/common/mojom/event_dispatcher.mojom.h"
- #include "extensions/renderer/bindings/api_response_validator.h"
- #include "extensions/renderer/bindings/event_emitter.h"
- #include "extensions/renderer/bindings/get_per_context_data.h"
- #include "extensions/renderer/bindings/js_runner.h"
- #include "gin/handle.h"
- #include "gin/per_context_data.h"
- namespace extensions {
- namespace {
- struct APIEventPerContextData : public base::SupportsUserData::Data {
- static constexpr char kPerContextDataKey[] = "extension_api_events";
- APIEventPerContextData(v8::Isolate* isolate) : isolate(isolate) {}
- ~APIEventPerContextData() override {
- DCHECK(emitters.empty())
- << "|emitters| should have been cleared by InvalidateContext()";
- DCHECK(massagers.empty())
- << "|massagers| should have been cleared by InvalidateContext()";
- DCHECK(anonymous_emitters.empty())
- << "|anonymous_emitters| should have been cleared by "
- << "InvalidateContext()";
- }
- // The associated v8::Isolate. Since this object is cleaned up at context
- // destruction, this should always be valid.
- v8::Isolate* isolate;
- // A map from event name -> event emitter.
- std::map<std::string, v8::Global<v8::Object>> emitters;
- // A map from event name -> argument massager.
- std::map<std::string, v8::Global<v8::Function>> massagers;
- // The collection of anonymous events.
- std::vector<v8::Global<v8::Object>> anonymous_emitters;
- static APIEventPerContextData* GetFrom(v8::Local<v8::Context> context,
- CreatePerContextData should_create) {
- return GetPerContextData<APIEventPerContextData>(context, should_create,
- context->GetIsolate());
- }
- };
- constexpr char APIEventPerContextData::kPerContextDataKey[];
- void DispatchEvent(const v8::FunctionCallbackInfo<v8::Value>& info) {
- v8::Isolate* isolate = info.GetIsolate();
- v8::HandleScope handle_scope(isolate);
- if (info.Length() != 1 || !info[0]->IsArray()) {
- NOTREACHED();
- return;
- }
- v8::Local<v8::Context> context = isolate->GetCurrentContext();
- APIEventPerContextData* data =
- APIEventPerContextData::GetFrom(context, kDontCreateIfMissing);
- DCHECK(data);
- std::string event_name = gin::V8ToString(isolate, info.Data());
- auto iter = data->emitters.find(event_name);
- if (iter == data->emitters.end())
- return;
- v8::Global<v8::Object>& v8_emitter = iter->second;
- std::vector<v8::Local<v8::Value>> args;
- CHECK(gin::Converter<std::vector<v8::Local<v8::Value>>>::FromV8(
- isolate, info[0], &args));
- EventEmitter* emitter = nullptr;
- gin::Converter<EventEmitter*>::FromV8(isolate, v8_emitter.Get(isolate),
- &emitter);
- CHECK(emitter);
- // Note: It's safe to use EventEmitter::FireSync() here because this should
- // only be triggered from a JS call, so we know JS is running.
- // TODO(devlin): It looks like the return result that requires this to be sync
- // is only used by the InputIME custom bindings; it would be kind of nice to
- // remove the dependency.
- info.GetReturnValue().Set(emitter->FireSync(context, &args, nullptr));
- }
- } // namespace
- APIEventHandler::APIEventHandler(
- const APIEventListeners::ListenersUpdated& listeners_changed,
- const APIEventListeners::ContextOwnerIdGetter& context_owner_id_getter,
- ExceptionHandler* exception_handler)
- : listeners_changed_(listeners_changed),
- context_owner_id_getter_(context_owner_id_getter),
- exception_handler_(exception_handler) {}
- APIEventHandler::~APIEventHandler() {}
- void APIEventHandler::SetResponseValidator(
- std::unique_ptr<APIResponseValidator> validator) {
- api_response_validator_ = std::move(validator);
- }
- v8::Local<v8::Object> APIEventHandler::CreateEventInstance(
- const std::string& event_name,
- bool supports_filters,
- bool supports_lazy_listeners,
- int max_listeners,
- bool notify_on_change,
- v8::Local<v8::Context> context) {
- // We need a context scope since gin::CreateHandle only takes the isolate
- // and infers the context from that.
- // TODO(devlin): This could be avoided if gin::CreateHandle could take a
- // context directly.
- v8::Context::Scope context_scope(context);
- APIEventPerContextData* data =
- APIEventPerContextData::GetFrom(context, kCreateIfMissing);
- DCHECK(data->emitters.find(event_name) == data->emitters.end());
- APIEventListeners::ListenersUpdated updated =
- notify_on_change ? listeners_changed_ : base::DoNothing();
- std::unique_ptr<APIEventListeners> listeners;
- if (supports_filters) {
- listeners = std::make_unique<FilteredEventListeners>(
- updated, event_name, context_owner_id_getter_, max_listeners,
- supports_lazy_listeners, &listener_tracker_);
- } else {
- listeners = std::make_unique<UnfilteredEventListeners>(
- updated, event_name, context_owner_id_getter_, max_listeners,
- supports_lazy_listeners, &listener_tracker_);
- }
- gin::Handle<EventEmitter> emitter_handle =
- gin::CreateHandle(context->GetIsolate(),
- new EventEmitter(supports_filters, std::move(listeners),
- exception_handler_));
- CHECK(!emitter_handle.IsEmpty());
- v8::Local<v8::Value> emitter_value = emitter_handle.ToV8();
- CHECK(emitter_value->IsObject());
- v8::Local<v8::Object> emitter_object =
- v8::Local<v8::Object>::Cast(emitter_value);
- data->emitters[event_name] =
- v8::Global<v8::Object>(context->GetIsolate(), emitter_object);
- return emitter_object;
- }
- v8::Local<v8::Object> APIEventHandler::CreateAnonymousEventInstance(
- v8::Local<v8::Context> context) {
- v8::Context::Scope context_scope(context);
- APIEventPerContextData* data =
- APIEventPerContextData::GetFrom(context, kCreateIfMissing);
- bool supports_filters = false;
- // Anonymous events are not tracked, and thus don't need a name or a context
- // owner.
- std::string empty_event_name;
- ListenerTracker* anonymous_listener_tracker = nullptr;
- std::unique_ptr<APIEventListeners> listeners =
- std::make_unique<UnfilteredEventListeners>(
- base::DoNothing(), empty_event_name,
- APIEventListeners::ContextOwnerIdGetter(), binding::kNoListenerMax,
- false, anonymous_listener_tracker);
- gin::Handle<EventEmitter> emitter_handle =
- gin::CreateHandle(context->GetIsolate(),
- new EventEmitter(supports_filters, std::move(listeners),
- exception_handler_));
- CHECK(!emitter_handle.IsEmpty());
- v8::Local<v8::Object> emitter_object = emitter_handle.ToV8().As<v8::Object>();
- data->anonymous_emitters.push_back(
- v8::Global<v8::Object>(context->GetIsolate(), emitter_object));
- return emitter_object;
- }
- void APIEventHandler::InvalidateCustomEvent(v8::Local<v8::Context> context,
- v8::Local<v8::Object> event) {
- EventEmitter* emitter = nullptr;
- APIEventPerContextData* data =
- APIEventPerContextData::GetFrom(context, kDontCreateIfMissing);
- // This could happen if a port (or JS) invalidates an event following
- // context destruction.
- // TODO(devlin): Is it better to fail gracefully here, or track all these
- // down for determinism?
- if (!data)
- return;
- if (!gin::Converter<EventEmitter*>::FromV8(context->GetIsolate(), event,
- &emitter)) {
- NOTREACHED();
- return;
- }
- emitter->Invalidate(context);
- auto emitter_entry = std::find(data->anonymous_emitters.begin(),
- data->anonymous_emitters.end(), event);
- if (emitter_entry == data->anonymous_emitters.end()) {
- NOTREACHED();
- return;
- }
- data->anonymous_emitters.erase(emitter_entry);
- }
- void APIEventHandler::FireEventInContext(const std::string& event_name,
- v8::Local<v8::Context> context,
- const base::Value::List& args,
- mojom::EventFilteringInfoPtr filter) {
- // Don't bother converting arguments if there are no listeners.
- // NOTE(devlin): This causes a double data and EventEmitter lookup, since
- // the v8 version below also checks for listeners. This should be very cheap,
- // but if we were really worried we could refactor.
- if (!HasListenerForEvent(event_name, context))
- return;
- // Note: since we only convert the arguments once, if a listener modifies an
- // object (including an array), other listeners will see that modification.
- // TODO(devlin): This is how it's always been, but should it be?
- std::unique_ptr<content::V8ValueConverter> converter =
- content::V8ValueConverter::Create();
- std::vector<v8::Local<v8::Value>> v8_args;
- v8_args.reserve(args.size());
- for (const auto& arg : args)
- v8_args.push_back(converter->ToV8Value(arg, context));
- FireEventInContext(event_name, context, &v8_args, std::move(filter),
- JSRunner::ResultCallback());
- }
- void APIEventHandler::FireEventInContext(
- const std::string& event_name,
- v8::Local<v8::Context> context,
- std::vector<v8::Local<v8::Value>>* arguments,
- mojom::EventFilteringInfoPtr filter,
- JSRunner::ResultCallback callback) {
- APIEventPerContextData* data =
- APIEventPerContextData::GetFrom(context, kDontCreateIfMissing);
- if (!data)
- return;
- auto iter = data->emitters.find(event_name);
- if (iter == data->emitters.end())
- return;
- EventEmitter* emitter = nullptr;
- gin::Converter<EventEmitter*>::FromV8(
- context->GetIsolate(), iter->second.Get(context->GetIsolate()), &emitter);
- CHECK(emitter);
- auto massager_iter = data->massagers.find(event_name);
- if (massager_iter == data->massagers.end()) {
- // Validate the event arguments if there are no massagers (and validation is
- // enabled). Unfortunately, massagers both transform the event args from
- // unexpected -> expected and (badly!) from expected -> unexpected. As such,
- // we simply don't validate if there's a massager attached to the event.
- // TODO(crbug.com/1329587): Ideally, we'd be able to validate the response
- // after the massagers run. This requires fixing our schema for at least
- // chrome.permissions events.
- if (api_response_validator_) {
- api_response_validator_->ValidateEvent(context, event_name, *arguments);
- }
- emitter->Fire(context, arguments, std::move(filter), std::move(callback));
- } else {
- DCHECK(!callback) << "Can't use an event callback with argument massagers.";
- v8::Isolate* isolate = context->GetIsolate();
- v8::HandleScope handle_scope(isolate);
- v8::Local<v8::Function> massager = massager_iter->second.Get(isolate);
- v8::Local<v8::Array> args_array =
- v8::Array::New(isolate, arguments->size());
- {
- // Massagers expect an array of v8 values. Since this is a newly-
- // constructed array and we're assigning data properties, this shouldn't
- // be able to fail or be visible by other script.
- for (size_t i = 0; i < arguments->size(); ++i) {
- v8::Maybe<bool> success = args_array->CreateDataProperty(
- context, static_cast<uint32_t>(i), arguments->at(i));
- CHECK(success.ToChecked());
- }
- }
- // Curry in the native dispatch function. Some argument massagers take
- // extra liberties and call this asynchronously, so we can't just have the
- // massager return a modified array of arguments.
- // We don't store this in a template because the Data (event name) is
- // different for each instance. Luckily, this is called during dispatching
- // an event, rather than e.g. at initialization time.
- v8::Local<v8::Function> dispatch_event =
- v8::Function::New(context, &DispatchEvent,
- gin::StringToSymbol(isolate, event_name))
- .ToLocalChecked();
- v8::Local<v8::Value> massager_args[] = {args_array, dispatch_event};
- JSRunner::Get(context)->RunJSFunction(
- massager, context, std::size(massager_args), massager_args);
- }
- }
- void APIEventHandler::RegisterArgumentMassager(
- v8::Local<v8::Context> context,
- const std::string& event_name,
- v8::Local<v8::Function> massager) {
- APIEventPerContextData* data =
- APIEventPerContextData::GetFrom(context, kCreateIfMissing);
- DCHECK(data->massagers.find(event_name) == data->massagers.end());
- data->massagers[event_name].Reset(context->GetIsolate(), massager);
- }
- bool APIEventHandler::HasListenerForEvent(const std::string& event_name,
- v8::Local<v8::Context> context) {
- APIEventPerContextData* data =
- APIEventPerContextData::GetFrom(context, kDontCreateIfMissing);
- if (!data)
- return false;
- auto iter = data->emitters.find(event_name);
- if (iter == data->emitters.end())
- return false;
- EventEmitter* emitter = nullptr;
- gin::Converter<EventEmitter*>::FromV8(
- context->GetIsolate(), iter->second.Get(context->GetIsolate()), &emitter);
- CHECK(emitter);
- return emitter->GetNumListeners() > 0;
- }
- void APIEventHandler::InvalidateContext(v8::Local<v8::Context> context) {
- DCHECK(gin::PerContextData::From(context))
- << "Trying to invalidate an already-invalid context.";
- APIEventPerContextData* data =
- APIEventPerContextData::GetFrom(context, kDontCreateIfMissing);
- if (!data)
- return;
- v8::Isolate* isolate = context->GetIsolate();
- v8::HandleScope scope(isolate);
- // This loop *shouldn't* allow any self-modification (i.e., no listeners
- // should be added or removed as a result of the iteration). If that changes,
- // we'll need to cache the listeners elsewhere before iterating.
- for (const auto& pair : data->emitters) {
- EventEmitter* emitter = nullptr;
- gin::Converter<EventEmitter*>::FromV8(isolate, pair.second.Get(isolate),
- &emitter);
- CHECK(emitter);
- emitter->Invalidate(context);
- }
- for (const auto& global : data->anonymous_emitters) {
- EventEmitter* emitter = nullptr;
- gin::Converter<EventEmitter*>::FromV8(isolate, global.Get(isolate),
- &emitter);
- CHECK(emitter);
- emitter->Invalidate(context);
- }
- data->emitters.clear();
- data->massagers.clear();
- data->anonymous_emitters.clear();
- // InvalidateContext() is called shortly (and, theoretically, synchronously)
- // before the PerContextData is deleted. We have a check that guarantees that
- // no new EventEmitters are created after the PerContextData is deleted, so
- // no new emitters should be created after this point.
- }
- size_t APIEventHandler::GetNumEventListenersForTesting(
- const std::string& event_name,
- v8::Local<v8::Context> context) {
- APIEventPerContextData* data =
- APIEventPerContextData::GetFrom(context, kDontCreateIfMissing);
- DCHECK(data);
- auto iter = data->emitters.find(event_name);
- DCHECK(iter != data->emitters.end());
- EventEmitter* emitter = nullptr;
- gin::Converter<EventEmitter*>::FromV8(
- context->GetIsolate(), iter->second.Get(context->GetIsolate()), &emitter);
- CHECK(emitter);
- return emitter->GetNumListeners();
- }
- } // namespace extensions
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