[Reland][Extensions Bindings] Add support for filtered events

extensions/renderer/api_event_listeners.cc

Index: extensions/renderer/api_event_listeners.cc
diff --git a/extensions/renderer/api_event_listeners.cc b/extensions/renderer/api_event_listeners.cc
new file mode 100644
index 0000000000000000000000000000000000000000..a59c9c6aa1fbcc2c05eeba41a319b4f9c201cde2
--- /dev/null
+++ b/extensions/renderer/api_event_listeners.cc
@@ -0,0 +1,254 @@
+// Copyright 2017 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/api_event_listeners.h"
+
+#include <algorithm>
+#include <memory>
+
+#include "base/memory/ptr_util.h"
+#include "content/public/child/v8_value_converter.h"
+#include "extensions/common/event_filter.h"
+#include "extensions/common/event_filtering_info.h"
+#include "extensions/common/event_matcher.h"
+#include "gin/converter.h"
+
+namespace extensions {
+
+namespace {
+
+// TODO(devlin): The EventFilter supports adding EventMatchers associated with
+// an id. For now, we ignore it and add/return everything associated with this
+// constant. We should rethink that.
+const int kIgnoreRoutingId = 0;
+
+// Pseudo-validates the given |filter| and converts it into a
+// base::DictionaryValue. Returns true on success.
+// TODO(devlin): This "validation" is pretty terrible. It matches the JS
+// equivalent, but it's lousy and makes it easy for users to get it wrong.
+// We should generate an argument spec for it and match it exactly.
+bool ValidateFilter(v8::Local<v8::Context> context,
+                    v8::Local<v8::Object> filter,
+                    std::unique_ptr<base::DictionaryValue>* filter_dict,
+                    std::string* error) {
+  v8::Isolate* isolate = context->GetIsolate();
+  v8::HandleScope handle_scope(isolate);
+
+  if (filter.IsEmpty()) {
+    *filter_dict = base::MakeUnique<base::DictionaryValue>();
+    return true;
+  }
+
+  v8::Local<v8::Value> url_filter;
+  if (!filter->Get(context, gin::StringToSymbol(isolate, "url"))
+           .ToLocal(&url_filter)) {
+    return false;
+  }
+
+  if (!url_filter->IsUndefined() && !url_filter->IsArray()) {
+    *error = "filters.url should be an array.";
+    return false;
+  }
+
+  v8::Local<v8::Value> service_type;
+  if (!filter->Get(context, gin::StringToSymbol(isolate, "serviceType"))
+           .ToLocal(&service_type)) {
+    return false;
+  }
+
+  if (!service_type->IsUndefined() && !service_type->IsString()) {
+    *error = "filters.serviceType should be a string.";
+    return false;
+  }
+
+  std::unique_ptr<content::V8ValueConverter> converter(
+      content::V8ValueConverter::create());
+  std::unique_ptr<base::Value> value = converter->FromV8Value(filter, context);
+  if (!value || !value->is_dict()) {
+    *error = "could not convert filter.";
+    return false;
+  }
+
+  *filter_dict = base::DictionaryValue::From(std::move(value));
+  return true;
+}
+
+}  // namespace
+
+UnfilteredEventListeners::UnfilteredEventListeners(
+    const ListenersUpdated& listeners_updated)
+    : listeners_updated_(listeners_updated) {}
+UnfilteredEventListeners::~UnfilteredEventListeners() = default;
+
+bool UnfilteredEventListeners::AddListener(v8::Local<v8::Function> listener,
+                                           v8::Local<v8::Object> filter,
+                                           v8::Local<v8::Context> context,
+                                           std::string* error) {
+  // |filter| should be checked before getting here.
+  DCHECK(filter.IsEmpty())
+      << "Filtered events should use FilteredEventListeners";
+
+  if (HasListener(listener))
+    return false;
+
+  listeners_.push_back(
+      v8::Global<v8::Function>(context->GetIsolate(), listener));
+  if (listeners_.size() == 1) {
+    listeners_updated_.Run(binding::EventListenersChanged::HAS_LISTENERS,
+                           nullptr, context);
+  }
+
+  return true;
+}
+
+void UnfilteredEventListeners::RemoveListener(v8::Local<v8::Function> listener,
+                                              v8::Local<v8::Context> context) {
+  auto iter = std::find(listeners_.begin(), listeners_.end(), listener);
+  if (iter == listeners_.end())
+    return;
+
+  listeners_.erase(iter);
+  if (listeners_.empty()) {
+    listeners_updated_.Run(binding::EventListenersChanged::NO_LISTENERS,
+                           nullptr, context);
+  }
+}
+
+bool UnfilteredEventListeners::HasListener(v8::Local<v8::Function> listener) {
+  return std::find(listeners_.begin(), listeners_.end(), listener) !=
+         listeners_.end();
+}
+
+size_t UnfilteredEventListeners::GetNumListeners() {
+  return listeners_.size();
+}
+
+std::vector<v8::Local<v8::Function>> UnfilteredEventListeners::GetListeners(
+    const EventFilteringInfo* filter,
+    v8::Local<v8::Context> context) {
+  std::vector<v8::Local<v8::Function>> listeners;
+  listeners.reserve(listeners_.size());
+  for (const auto& listener : listeners_)
+    listeners.push_back(listener.Get(context->GetIsolate()));
+  return listeners;
+}
+
+void UnfilteredEventListeners::Invalidate(v8::Local<v8::Context> context) {
+  if (!listeners_.empty()) {
+    listeners_.clear();
+    listeners_updated_.Run(binding::EventListenersChanged::NO_LISTENERS,
+                           nullptr, context);
+  }
+}
+
+struct FilteredEventListeners::ListenerData {
+  bool operator==(v8::Local<v8::Function> other_function) const {
+    // Note that we only consider the listener function here, and not the
+    // filter. This implies that it's invalid to try and add the same
+    // function for multiple filters.
+    // TODO(devlin): It's always been this way, but should it be?
+    return function == other_function;
+  }
+
+  v8::Global<v8::Function> function;
+  int filter_id;
+};
+
+FilteredEventListeners::FilteredEventListeners(
+    const ListenersUpdated& listeners_updated,
+    const std::string& event_name,
+    EventFilter* event_filter)
+    : listeners_updated_(listeners_updated),
+      event_name_(event_name),
+      event_filter_(event_filter) {}
+FilteredEventListeners::~FilteredEventListeners() = default;
+
+bool FilteredEventListeners::AddListener(v8::Local<v8::Function> listener,
+                                         v8::Local<v8::Object> filter,
+                                         v8::Local<v8::Context> context,
+                                         std::string* error) {
+  if (HasListener(listener))
+    return false;
+
+  std::unique_ptr<base::DictionaryValue> filter_dict;
+  if (!ValidateFilter(context, filter, &filter_dict, error))
+    return false;
+
+  int filter_id = event_filter_->AddEventMatcher(
+      event_name_,
+      base::MakeUnique<EventMatcher>(std::move(filter_dict), kIgnoreRoutingId));
+
+  if (filter_id == -1) {
+    *error = "Could not add listener";
+    return false;
+  }
+
+  const EventMatcher* matcher = event_filter_->GetEventMatcher(filter_id);
+  DCHECK(matcher);
+  listeners_.push_back(
+      {v8::Global<v8::Function>(context->GetIsolate(), listener), filter_id});
+  if (value_counter_.Add(*matcher->value())) {
+    listeners_updated_.Run(binding::EventListenersChanged::HAS_LISTENERS,
+                           matcher->value(), context);
+  }
+
+  return true;
+}
+
+void FilteredEventListeners::RemoveListener(v8::Local<v8::Function> listener,
+                                            v8::Local<v8::Context> context) {
+  auto iter = std::find(listeners_.begin(), listeners_.end(), listener);
+  if (iter == listeners_.end())
+    return;
+
+  ListenerData data = std::move(*iter);
+  listeners_.erase(iter);
+
+  InvalidateListener(data, context);
+}
+
+bool FilteredEventListeners::HasListener(v8::Local<v8::Function> listener) {
+  return std::find(listeners_.begin(), listeners_.end(), listener) !=
+         listeners_.end();
+}
+
+size_t FilteredEventListeners::GetNumListeners() {
+  return listeners_.size();
+}
+
+std::vector<v8::Local<v8::Function>> FilteredEventListeners::GetListeners(
+    const EventFilteringInfo* filter,
+    v8::Local<v8::Context> context) {
+  std::set<int> ids = event_filter_->MatchEvent(
+      event_name_, filter ? *filter : EventFilteringInfo(), kIgnoreRoutingId);
+
+  std::vector<v8::Local<v8::Function>> listeners;
+  listeners.reserve(ids.size());
+  for (const auto& listener : listeners_) {
+    if (ids.count(listener.filter_id))
+      listeners.push_back(listener.function.Get(context->GetIsolate()));
+  }
+  return listeners;
+}
+
+void FilteredEventListeners::Invalidate(v8::Local<v8::Context> context) {
+  for (const auto& listener : listeners_)
+    InvalidateListener(listener, context);
+  listeners_.clear();
+}
+
+void FilteredEventListeners::InvalidateListener(
+    const ListenerData& listener,
+    v8::Local<v8::Context> context) {
+  EventMatcher* matcher = event_filter_->GetEventMatcher(listener.filter_id);
+  DCHECK(matcher);
+  if (value_counter_.Remove(*matcher->value())) {
+    listeners_updated_.Run(binding::EventListenersChanged::NO_LISTENERS,
+                           matcher->value(), context);
+  }
+
+  event_filter_->RemoveEventMatcher(listener.filter_id);
+}
+
+}  // namespace extensions