[Extensions Bindings] Add a bindings/ subdirectory under renderer

extensions/renderer/event_emitter.cc

-// 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/event_emitter.h"
-
-#include <algorithm>
-
-#include "extensions/renderer/api_event_listeners.h"
-#include "gin/data_object_builder.h"
-#include "gin/object_template_builder.h"
-#include "gin/per_context_data.h"
-
-namespace extensions {
-
-gin::WrapperInfo EventEmitter::kWrapperInfo = {gin::kEmbedderNativeGin};
-
-EventEmitter::EventEmitter(bool supports_filters,
-                           std::unique_ptr<APIEventListeners> listeners,
-                           const binding::RunJSFunction& run_js,
-                           const binding::RunJSFunctionSync& run_js_sync)
-    : supports_filters_(supports_filters),
-      listeners_(std::move(listeners)),
-      run_js_(run_js),
-      run_js_sync_(run_js_sync) {}
-
-EventEmitter::~EventEmitter() {}
-
-gin::ObjectTemplateBuilder EventEmitter::GetObjectTemplateBuilder(
-    v8::Isolate* isolate) {
-  return Wrappable<EventEmitter>::GetObjectTemplateBuilder(isolate)
-      .SetMethod("addListener", &EventEmitter::AddListener)
-      .SetMethod("removeListener", &EventEmitter::RemoveListener)
-      .SetMethod("hasListener", &EventEmitter::HasListener)
-      .SetMethod("hasListeners", &EventEmitter::HasListeners)
-      // The following methods aren't part of the public API, but are used
-      // by our custom bindings and exposed on the public event object. :(
-      // TODO(devlin): Once we convert all custom bindings that use these,
-      // they can be removed.
-      .SetMethod("dispatch", &EventEmitter::Dispatch);
-}
-
-void EventEmitter::Fire(v8::Local<v8::Context> context,
-                        std::vector<v8::Local<v8::Value>>* args,
-                        const EventFilteringInfo* filter) {
-  bool run_sync = false;
-  DispatchImpl(context, args, filter, run_sync, nullptr);
-}
-
-void EventEmitter::Invalidate(v8::Local<v8::Context> context) {
-  valid_ = false;
-  listeners_->Invalidate(context);
-}
-
-size_t EventEmitter::GetNumListeners() const {
-  return listeners_->GetNumListeners();
-}
-
-void EventEmitter::AddListener(gin::Arguments* arguments) {
-  // If script from another context maintains a reference to this object, it's
-  // possible that functions can be called after this object's owning context
-  // is torn down and released by blink. We don't support this behavior, but
-  // we need to make sure nothing crashes, so early out of methods.
-  if (!valid_)
-    return;
-
-  v8::Local<v8::Function> listener;
-  // TODO(devlin): For some reason, we don't throw an error when someone calls
-  // add/removeListener with no argument. We probably should. For now, keep
-  // the status quo, but we should revisit this.
-  if (!arguments->GetNext(&listener))
-    return;
-
-  if (!arguments->PeekNext().IsEmpty() && !supports_filters_) {
-    arguments->ThrowTypeError("This event does not support filters");
-    return;
-  }
-
-  v8::Local<v8::Object> filter;
-  if (!arguments->PeekNext().IsEmpty() && !arguments->GetNext(&filter)) {
-    arguments->ThrowTypeError("Invalid invocation");
-    return;
-  }
-
-  v8::Local<v8::Context> context = arguments->GetHolderCreationContext();
-  if (!gin::PerContextData::From(context))
-    return;
-
-  std::string error;
-  if (!listeners_->AddListener(listener, filter, context, &error) &&
-      !error.empty()) {
-    arguments->ThrowTypeError(error);
-  }
-}
-
-void EventEmitter::RemoveListener(gin::Arguments* arguments) {
-  // See comment in AddListener().
-  if (!valid_)
-    return;
-
-  v8::Local<v8::Function> listener;
-  // See comment in AddListener().
-  if (!arguments->GetNext(&listener))
-    return;
-
-  listeners_->RemoveListener(listener, arguments->GetHolderCreationContext());
-}
-
-bool EventEmitter::HasListener(v8::Local<v8::Function> listener) {
-  return listeners_->HasListener(listener);
-}
-
-bool EventEmitter::HasListeners() {
-  return listeners_->GetNumListeners() != 0;
-}
-
-void EventEmitter::Dispatch(gin::Arguments* arguments) {
-  if (!valid_)
-    return;
-
-  if (listeners_->GetNumListeners() == 0)
-    return;
-
-  v8::Isolate* isolate = arguments->isolate();
-  v8::HandleScope handle_scope(isolate);
-  v8::Local<v8::Context> context = isolate->GetCurrentContext();
-  std::vector<v8::Local<v8::Value>> v8_args = arguments->GetAll();
-
-  // Dispatch() is called from JS, and sometimes expects a return value of an
-  // array with entries for each of the results of the listeners. Since this is
-  // directly from JS, we know it should be safe to call synchronously and use
-  // the return result, so we don't use Fire().
-  // TODO(devlin): It'd be nice to refactor anything expecting a result here so
-  // we don't have to have this special logic, especially since script could
-  // potentially tweak the result object through prototype manipulation (which
-  // also means we should never use this for security decisions).
-  bool run_sync = true;
-  std::vector<v8::Global<v8::Value>> listener_responses;
-  DispatchImpl(context, &v8_args, nullptr, run_sync, &listener_responses);
-
-  if (!listener_responses.size()) {
-    // Return nothing if there are no responses. This is the behavior of the
-    // current JS implementation.
-    return;
-  }
-
-  v8::Local<v8::Object> result;
-  {
-    v8::TryCatch try_catch(isolate);
-    try_catch.SetVerbose(true);
-    v8::Local<v8::Array> v8_responses =
-        v8::Array::New(isolate, listener_responses.size());
-    for (size_t i = 0; i < listener_responses.size(); ++i) {
-      // TODO(devlin): With more than 2^32 - 2 listeners, this can get nasty.
-      // We shouldn't reach that point, but it would be good to add enforcement.
-      CHECK(v8_responses
-                ->CreateDataProperty(context, i,
-                                     listener_responses[i].Get(isolate))
-                .ToChecked());
-    }
-
-    result = gin::DataObjectBuilder(isolate)
-                 .Set("results", v8_responses.As<v8::Value>())
-                 .Build();
-  }
-  arguments->Return(result);
-}
-
-void EventEmitter::DispatchImpl(
-    v8::Local<v8::Context> context,
-    std::vector<v8::Local<v8::Value>>* args,
-    const EventFilteringInfo* filter,
-    bool run_sync,
-    std::vector<v8::Global<v8::Value>>* out_values) {
-  // Note that |listeners_| can be modified during handling.
-  std::vector<v8::Local<v8::Function>> listeners =
-      listeners_->GetListeners(filter, context);
-
-  v8::Isolate* isolate = context->GetIsolate();
-  v8::TryCatch try_catch(isolate);
-  // SetVerbose() means the error will still get logged, which is what we
-  // want. We don't let it bubble up any further to prevent it from being
-  // surfaced in e.g. JS code that triggered the event.
-  try_catch.SetVerbose(true);
-  for (const auto& listener : listeners) {
-    if (run_sync) {
-      DCHECK(out_values);
-      v8::Global<v8::Value> result =
-          run_js_sync_.Run(listener, context, args->size(), args->data());
-      if (!result.IsEmpty() && !result.Get(isolate)->IsUndefined())
-        out_values->push_back(std::move(result));
-    } else {
-      run_js_.Run(listener, context, args->size(), args->data());
-    }
-  }
-}
-
-}  // namespace extensions