extensions/renderer/event_bindings.cc

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "extensions/renderer/event_bindings.h"
   6
   7 #include <map>
   8 #include <set>
   9 #include <string>
  10 #include <vector>
  11
  12 #include "base/basictypes.h"
  13 #include "base/bind.h"
  14 #include "base/lazy_instance.h"
  15 #include "base/memory/scoped_ptr.h"
  16 #include "content/public/renderer/render_thread.h"
  17 #include "content/public/renderer/render_view.h"
  18 #include "content/public/renderer/v8_value_converter.h"
  19 #include "extensions/common/event_filter.h"
  20 #include "extensions/common/extension.h"
  21 #include "extensions/common/extension_messages.h"
  22 #include "extensions/common/manifest_handlers/background_info.h"
  23 #include "extensions/common/value_counter.h"
  24 #include "extensions/renderer/dispatcher.h"
  25 #include "extensions/renderer/extension_helper.h"
  26 #include "extensions/renderer/object_backed_native_handler.h"
  27 #include "url/gurl.h"
  28 #include "v8/include/v8.h"
  29
  30 namespace extensions {
  31
  32 namespace {
  33
  34 // A map of event names to the number of contexts listening to that event.
  35 // We notify the browser about event listeners when we transition between 0
  36 // and 1.
  37 typedef std::map<std::string, int> EventListenerCounts;
  38
  39 // A map of extension IDs to listener counts for that extension.
  40 base::LazyInstance<std::map<std::string, EventListenerCounts> >
  41     g_listener_counts = LAZY_INSTANCE_INITIALIZER;
  42
  43 // A map of event names to a (filter -> count) map. The map is used to keep
  44 // track of which filters are in effect for which events.
  45 // We notify the browser about filtered event listeners when we transition
  46 // between 0 and 1.
  47 typedef std::map<std::string, linked_ptr<ValueCounter> >
  48     FilteredEventListenerCounts;
  49
  50 // A map of extension IDs to filtered listener counts for that extension.
  51 base::LazyInstance<std::map<std::string, FilteredEventListenerCounts> >
  52     g_filtered_listener_counts = LAZY_INSTANCE_INITIALIZER;
  53
  54 base::LazyInstance<EventFilter> g_event_filter = LAZY_INSTANCE_INITIALIZER;
  55
  56 bool IsLazyBackgroundPage(content::RenderView* render_view,
  57                           const Extension* extension) {
  58   if (!render_view)
  59     return false;
  60   ExtensionHelper* helper = ExtensionHelper::Get(render_view);
  61   return (extension && BackgroundInfo::HasLazyBackgroundPage(extension) &&
  62           helper->view_type() == VIEW_TYPE_EXTENSION_BACKGROUND_PAGE);
  63 }
  64
  65 EventFilteringInfo ParseFromObject(v8::Handle<v8::Object> object,
  66                                    v8::Isolate* isolate) {
  67   EventFilteringInfo info;
  68   v8::Handle<v8::String> url(v8::String::NewFromUtf8(isolate, "url"));
  69   if (object->Has(url)) {
  70     v8::Handle<v8::Value> url_value(object->Get(url));
  71     info.SetURL(GURL(*v8::String::Utf8Value(url_value)));
  72   }
  73   v8::Handle<v8::String> instance_id(
  74       v8::String::NewFromUtf8(isolate, "instanceId"));
  75   if (object->Has(instance_id)) {
  76     v8::Handle<v8::Value> instance_id_value(object->Get(instance_id));
  77     info.SetInstanceID(instance_id_value->IntegerValue());
  78   }
  79   v8::Handle<v8::String> service_type(
  80       v8::String::NewFromUtf8(isolate, "serviceType"));
  81   if (object->Has(service_type)) {
  82     v8::Handle<v8::Value> service_type_value(object->Get(service_type));
  83     info.SetServiceType(*v8::String::Utf8Value(service_type_value));
  84   }
  85   return info;
  86 }
  87
  88 // Add a filter to |event_name| in |extension_id|, returning true if it
  89 // was the first filter for that event in that extension.
  90 bool AddFilter(const std::string& event_name,
  91                const std::string& extension_id,
  92                base::DictionaryValue* filter) {
  93   FilteredEventListenerCounts& counts =
  94       g_filtered_listener_counts.Get()[extension_id];
  95   FilteredEventListenerCounts::iterator it = counts.find(event_name);
  96   if (it == counts.end())
  97     counts[event_name].reset(new ValueCounter);
  98
  99   int result = counts[event_name]->Add(*filter);
 100   return 1 == result;
 101 }
 102
 103 // Remove a filter from |event_name| in |extension_id|, returning true if it
 104 // was the last filter for that event in that extension.
 105 bool RemoveFilter(const std::string& event_name,
 106                   const std::string& extension_id,
 107                   base::DictionaryValue* filter) {
 108   FilteredEventListenerCounts& counts =
 109       g_filtered_listener_counts.Get()[extension_id];
 110   FilteredEventListenerCounts::iterator it = counts.find(event_name);
 111   if (it == counts.end())
 112     return false;
 113   return 0 == it->second->Remove(*filter);
 114 }
 115
 116 }  // namespace
 117
 118 EventBindings::EventBindings(Dispatcher* dispatcher, ScriptContext* context)
 119     : ObjectBackedNativeHandler(context), dispatcher_(dispatcher) {
 120   RouteFunction(
 121       "AttachEvent",
 122       base::Bind(&EventBindings::AttachEvent, base::Unretained(this)));
 123   RouteFunction(
 124       "DetachEvent",
 125       base::Bind(&EventBindings::DetachEvent, base::Unretained(this)));
 126   RouteFunction(
 127       "AttachFilteredEvent",
 128       base::Bind(&EventBindings::AttachFilteredEvent, base::Unretained(this)));
 129   RouteFunction(
 130       "DetachFilteredEvent",
 131       base::Bind(&EventBindings::DetachFilteredEvent, base::Unretained(this)));
 132   RouteFunction("MatchAgainstEventFilter",
 133                 base::Bind(&EventBindings::MatchAgainstEventFilter,
 134                            base::Unretained(this)));
 135 }
 136
 137 EventBindings::~EventBindings() {}
 138
 139 // Attach an event name to an object.
 140 void EventBindings::AttachEvent(
 141     const v8::FunctionCallbackInfo<v8::Value>& args) {
 142   CHECK_EQ(1, args.Length());
 143   CHECK(args[0]->IsString());
 144
 145   std::string event_name = *v8::String::Utf8Value(args[0]->ToString());
 146
 147   if (!dispatcher_->CheckContextAccessToExtensionAPI(event_name, context()))
 148     return;
 149
 150   std::string extension_id = context()->GetExtensionID();
 151   EventListenerCounts& listener_counts = g_listener_counts.Get()[extension_id];
 152   if (++listener_counts[event_name] == 1) {
 153     content::RenderThread::Get()->Send(new ExtensionHostMsg_AddListener(
 154         extension_id, context()->GetURL(), event_name));
 155   }
 156
 157   // This is called the first time the page has added a listener. Since
 158   // the background page is the only lazy page, we know this is the first
 159   // time this listener has been registered.
 160   if (IsLazyBackgroundPage(context()->GetRenderView(),
 161                            context()->extension())) {
 162     content::RenderThread::Get()->Send(
 163         new ExtensionHostMsg_AddLazyListener(extension_id, event_name));
 164   }
 165 }
 166
 167 void EventBindings::DetachEvent(
 168     const v8::FunctionCallbackInfo<v8::Value>& args) {
 169   CHECK_EQ(2, args.Length());
 170   CHECK(args[0]->IsString());
 171   CHECK(args[1]->IsBoolean());
 172
 173   std::string event_name = *v8::String::Utf8Value(args[0]);
 174   bool is_manual = args[1]->BooleanValue();
 175
 176   std::string extension_id = context()->GetExtensionID();
 177   EventListenerCounts& listener_counts = g_listener_counts.Get()[extension_id];
 178
 179   if (--listener_counts[event_name] == 0) {
 180     content::RenderThread::Get()->Send(new ExtensionHostMsg_RemoveListener(
 181         extension_id, context()->GetURL(), event_name));
 182   }
 183
 184   // DetachEvent is called when the last listener for the context is
 185   // removed. If the context is the background page, and it removes the
 186   // last listener manually, then we assume that it is no longer interested
 187   // in being awakened for this event.
 188   if (is_manual && IsLazyBackgroundPage(context()->GetRenderView(),
 189                                         context()->extension())) {
 190     content::RenderThread::Get()->Send(
 191         new ExtensionHostMsg_RemoveLazyListener(extension_id, event_name));
 192   }
 193 }
 194
 195 // MatcherID AttachFilteredEvent(string event_name, object filter)
 196 // event_name - Name of the event to attach.
 197 // filter - Which instances of the named event are we interested in.
 198 // returns the id assigned to the listener, which will be returned from calls
 199 // to MatchAgainstEventFilter where this listener matches.
 200 void EventBindings::AttachFilteredEvent(
 201     const v8::FunctionCallbackInfo<v8::Value>& args) {
 202   CHECK_EQ(2, args.Length());
 203   CHECK(args[0]->IsString());
 204   CHECK(args[1]->IsObject());
 205
 206   std::string event_name = *v8::String::Utf8Value(args[0]);
 207
 208   // This method throws an exception if it returns false.
 209   if (!dispatcher_->CheckContextAccessToExtensionAPI(event_name, context()))
 210     return;
 211
 212   std::string extension_id = context()->GetExtensionID();
 213
 214   scoped_ptr<base::DictionaryValue> filter;
 215   scoped_ptr<content::V8ValueConverter> converter(
 216       content::V8ValueConverter::create());
 217
 218   base::DictionaryValue* filter_dict = NULL;
 219   base::Value* filter_value =
 220       converter->FromV8Value(args[1]->ToObject(), context()->v8_context());
 221   if (!filter_value) {
 222     args.GetReturnValue().Set(static_cast<int32_t>(-1));
 223     return;
 224   }
 225   if (!filter_value->GetAsDictionary(&filter_dict)) {
 226     delete filter_value;
 227     args.GetReturnValue().Set(static_cast<int32_t>(-1));
 228     return;
 229   }
 230
 231   filter.reset(filter_dict);
 232   EventFilter& event_filter = g_event_filter.Get();
 233   int id =
 234       event_filter.AddEventMatcher(event_name, ParseEventMatcher(filter.get()));
 235
 236   // Only send IPCs the first time a filter gets added.
 237   if (AddFilter(event_name, extension_id, filter.get())) {
 238     bool lazy = IsLazyBackgroundPage(context()->GetRenderView(),
 239                                      context()->extension());
 240     content::RenderThread::Get()->Send(new ExtensionHostMsg_AddFilteredListener(
 241         extension_id, event_name, *filter, lazy));
 242   }
 243
 244   args.GetReturnValue().Set(static_cast<int32_t>(id));
 245 }
 246
 247 void EventBindings::DetachFilteredEvent(
 248     const v8::FunctionCallbackInfo<v8::Value>& args) {
 249   CHECK_EQ(2, args.Length());
 250   CHECK(args[0]->IsInt32());
 251   CHECK(args[1]->IsBoolean());
 252   bool is_manual = args[1]->BooleanValue();
 253
 254   std::string extension_id = context()->GetExtensionID();
 255
 256   int matcher_id = args[0]->Int32Value();
 257   EventFilter& event_filter = g_event_filter.Get();
 258   EventMatcher* event_matcher = event_filter.GetEventMatcher(matcher_id);
 259
 260   const std::string& event_name = event_filter.GetEventName(matcher_id);
 261
 262   // Only send IPCs the last time a filter gets removed.
 263   if (RemoveFilter(event_name, extension_id, event_matcher->value())) {
 264     bool lazy = is_manual && IsLazyBackgroundPage(context()->GetRenderView(),
 265                                                   context()->extension());
 266     content::RenderThread::Get()->Send(
 267         new ExtensionHostMsg_RemoveFilteredListener(
 268             extension_id, event_name, *event_matcher->value(), lazy));
 269   }
 270
 271   event_filter.RemoveEventMatcher(matcher_id);
 272 }
 273
 274 void EventBindings::MatchAgainstEventFilter(
 275     const v8::FunctionCallbackInfo<v8::Value>& args) {
 276   v8::Isolate* isolate = args.GetIsolate();
 277   typedef std::set<EventFilter::MatcherID> MatcherIDs;
 278   EventFilter& event_filter = g_event_filter.Get();
 279   std::string event_name = *v8::String::Utf8Value(args[0]->ToString());
 280   EventFilteringInfo info = ParseFromObject(args[1]->ToObject(), isolate);
 281   // Only match events routed to this context's RenderView or ones that don't
 282   // have a routingId in their filter.
 283   MatcherIDs matched_event_filters = event_filter.MatchEvent(
 284       event_name, info, context()->GetRenderView()->GetRoutingID());
 285   v8::Handle<v8::Array> array(
 286       v8::Array::New(isolate, matched_event_filters.size()));
 287   int i = 0;
 288   for (MatcherIDs::iterator it = matched_event_filters.begin();
 289        it != matched_event_filters.end();
 290        ++it) {
 291     array->Set(v8::Integer::New(isolate, i++), v8::Integer::New(isolate, *it));
 292   }
 293   args.GetReturnValue().Set(array);
 294 }
 295
 296 scoped_ptr<EventMatcher> EventBindings::ParseEventMatcher(
 297     base::DictionaryValue* filter_dict) {
 298   return scoped_ptr<EventMatcher>(new EventMatcher(
 299       scoped_ptr<base::DictionaryValue>(filter_dict->DeepCopy()),
 300       context()->GetRenderView()->GetRoutingID()));
 301 }
 302
 303 }  // namespace extensions