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 "components/crx_file/id_util.h"
  17 #include "content/public/renderer/render_thread.h"
  18 #include "content/public/renderer/render_view.h"
  19 #include "content/public/renderer/v8_value_converter.h"
  20 #include "extensions/common/event_filter.h"
  21 #include "extensions/common/extension.h"
  22 #include "extensions/common/extension_messages.h"
  23 #include "extensions/common/manifest_handlers/background_info.h"
  24 #include "extensions/common/value_counter.h"
  25 #include "extensions/renderer/dispatcher.h"
  26 #include "extensions/renderer/extension_helper.h"
  27 #include "extensions/renderer/object_backed_native_handler.h"
  28 #include "url/gurl.h"
  29 #include "v8/include/v8.h"
  30
  31 namespace extensions {
  32
  33 namespace {
  34
  35 // A map of event names to the number of contexts listening to that event.
  36 // We notify the browser about event listeners when we transition between 0
  37 // and 1.
  38 typedef std::map<std::string, int> EventListenerCounts;
  39
  40 // A map of extension IDs to listener counts for that extension.
  41 base::LazyInstance<std::map<std::string, EventListenerCounts> >
  42     g_listener_counts = LAZY_INSTANCE_INITIALIZER;
  43
  44 // A map of event names to a (filter -> count) map. The map is used to keep
  45 // track of which filters are in effect for which events.
  46 // We notify the browser about filtered event listeners when we transition
  47 // between 0 and 1.
  48 typedef std::map<std::string, linked_ptr<ValueCounter> >
  49     FilteredEventListenerCounts;
  50
  51 // A map of extension IDs to filtered listener counts for that extension.
  52 base::LazyInstance<std::map<std::string, FilteredEventListenerCounts> >
  53     g_filtered_listener_counts = LAZY_INSTANCE_INITIALIZER;
  54
  55 base::LazyInstance<EventFilter> g_event_filter = LAZY_INSTANCE_INITIALIZER;
  56
  57 std::string GetKeyForScriptContext(ScriptContext* script_context) {
  58   const std::string& extension_id = script_context->GetExtensionID();
  59   CHECK(crx_file::id_util::IdIsValid(extension_id) ||
  60         script_context->GetURL().is_valid());
  61   return crx_file::id_util::IdIsValid(extension_id)
  62              ? extension_id
  63              : script_context->GetURL().spec();
  64 }
  65
  66 // Increments the number of event-listeners for the given |event_name| and
  67 // ScriptContext. Returns the count after the increment.
  68 int IncrementEventListenerCount(ScriptContext* script_context,
  69                                 const std::string& event_name) {
  70   return ++g_listener_counts
  71                .Get()[GetKeyForScriptContext(script_context)][event_name];
  72 }
  73
  74 // Decrements the number of event-listeners for the given |event_name| and
  75 // ScriptContext. Returns the count after the increment.
  76 int DecrementEventListenerCount(ScriptContext* script_context,
  77                                 const std::string& event_name) {
  78   return --g_listener_counts
  79                .Get()[GetKeyForScriptContext(script_context)][event_name];
  80 }
  81
  82 bool IsLazyBackgroundPage(content::RenderView* render_view,
  83                           const Extension* extension) {
  84   if (!render_view)
  85     return false;
  86   ExtensionHelper* helper = ExtensionHelper::Get(render_view);
  87   return (extension && BackgroundInfo::HasLazyBackgroundPage(extension) &&
  88           helper->view_type() == VIEW_TYPE_EXTENSION_BACKGROUND_PAGE);
  89 }
  90
  91 EventFilteringInfo ParseFromObject(v8::Handle<v8::Object> object,
  92                                    v8::Isolate* isolate) {
  93   EventFilteringInfo info;
  94   v8::Handle<v8::String> url(v8::String::NewFromUtf8(isolate, "url"));
  95   if (object->Has(url)) {
  96     v8::Handle<v8::Value> url_value(object->Get(url));
  97     info.SetURL(GURL(*v8::String::Utf8Value(url_value)));
  98   }
  99   v8::Handle<v8::String> instance_id(
 100       v8::String::NewFromUtf8(isolate, "instanceId"));
 101   if (object->Has(instance_id)) {
 102     v8::Handle<v8::Value> instance_id_value(object->Get(instance_id));
 103     info.SetInstanceID(instance_id_value->IntegerValue());
 104   }
 105   v8::Handle<v8::String> service_type(
 106       v8::String::NewFromUtf8(isolate, "serviceType"));
 107   if (object->Has(service_type)) {
 108     v8::Handle<v8::Value> service_type_value(object->Get(service_type));
 109     info.SetServiceType(*v8::String::Utf8Value(service_type_value));
 110   }
 111   return info;
 112 }
 113
 114 // Add a filter to |event_name| in |extension_id|, returning true if it
 115 // was the first filter for that event in that extension.
 116 bool AddFilter(const std::string& event_name,
 117                const std::string& extension_id,
 118                base::DictionaryValue* filter) {
 119   FilteredEventListenerCounts& counts =
 120       g_filtered_listener_counts.Get()[extension_id];
 121   FilteredEventListenerCounts::iterator it = counts.find(event_name);
 122   if (it == counts.end())
 123     counts[event_name].reset(new ValueCounter);
 124
 125   int result = counts[event_name]->Add(*filter);
 126   return 1 == result;
 127 }
 128
 129 // Remove a filter from |event_name| in |extension_id|, returning true if it
 130 // was the last filter for that event in that extension.
 131 bool RemoveFilter(const std::string& event_name,
 132                   const std::string& extension_id,
 133                   base::DictionaryValue* filter) {
 134   FilteredEventListenerCounts& counts =
 135       g_filtered_listener_counts.Get()[extension_id];
 136   FilteredEventListenerCounts::iterator it = counts.find(event_name);
 137   if (it == counts.end())
 138     return false;
 139   return 0 == it->second->Remove(*filter);
 140 }
 141
 142 }  // namespace
 143
 144 EventBindings::EventBindings(Dispatcher* dispatcher, ScriptContext* context)
 145     : ObjectBackedNativeHandler(context), dispatcher_(dispatcher) {
 146   RouteFunction(
 147       "AttachEvent",
 148       base::Bind(&EventBindings::AttachEvent, base::Unretained(this)));
 149   RouteFunction(
 150       "DetachEvent",
 151       base::Bind(&EventBindings::DetachEvent, base::Unretained(this)));
 152   RouteFunction(
 153       "AttachFilteredEvent",
 154       base::Bind(&EventBindings::AttachFilteredEvent, base::Unretained(this)));
 155   RouteFunction(
 156       "DetachFilteredEvent",
 157       base::Bind(&EventBindings::DetachFilteredEvent, base::Unretained(this)));
 158   RouteFunction("MatchAgainstEventFilter",
 159                 base::Bind(&EventBindings::MatchAgainstEventFilter,
 160                            base::Unretained(this)));
 161 }
 162
 163 EventBindings::~EventBindings() {}
 164
 165 // Attach an event name to an object.
 166 void EventBindings::AttachEvent(
 167     const v8::FunctionCallbackInfo<v8::Value>& args) {
 168   CHECK_EQ(1, args.Length());
 169   CHECK(args[0]->IsString());
 170
 171   std::string event_name = *v8::String::Utf8Value(args[0]);
 172
 173   if (!dispatcher_->CheckContextAccessToExtensionAPI(event_name, context()))
 174     return;
 175
 176   const std::string& extension_id = context()->GetExtensionID();
 177   if (IncrementEventListenerCount(context(), event_name) == 1) {
 178     content::RenderThread::Get()->Send(new ExtensionHostMsg_AddListener(
 179         extension_id, context()->GetURL(), event_name));
 180   }
 181
 182   // This is called the first time the page has added a listener. Since
 183   // the background page is the only lazy page, we know this is the first
 184   // time this listener has been registered.
 185   if (IsLazyBackgroundPage(context()->GetRenderView(),
 186                            context()->extension())) {
 187     content::RenderThread::Get()->Send(
 188         new ExtensionHostMsg_AddLazyListener(extension_id, event_name));
 189   }
 190 }
 191
 192 void EventBindings::DetachEvent(
 193     const v8::FunctionCallbackInfo<v8::Value>& args) {
 194   CHECK_EQ(2, args.Length());
 195   CHECK(args[0]->IsString());
 196   CHECK(args[1]->IsBoolean());
 197
 198   std::string event_name = *v8::String::Utf8Value(args[0]);
 199   bool is_manual = args[1]->BooleanValue();
 200
 201   const std::string& extension_id = context()->GetExtensionID();
 202   if (DecrementEventListenerCount(context(), event_name) == 0) {
 203     content::RenderThread::Get()->Send(new ExtensionHostMsg_RemoveListener(
 204         extension_id, context()->GetURL(), event_name));
 205   }
 206
 207   // DetachEvent is called when the last listener for the context is
 208   // removed. If the context is the background page, and it removes the
 209   // last listener manually, then we assume that it is no longer interested
 210   // in being awakened for this event.
 211   if (is_manual && IsLazyBackgroundPage(context()->GetRenderView(),
 212                                         context()->extension())) {
 213     content::RenderThread::Get()->Send(
 214         new ExtensionHostMsg_RemoveLazyListener(extension_id, event_name));
 215   }
 216 }
 217
 218 // MatcherID AttachFilteredEvent(string event_name, object filter)
 219 // event_name - Name of the event to attach.
 220 // filter - Which instances of the named event are we interested in.
 221 // returns the id assigned to the listener, which will be returned from calls
 222 // to MatchAgainstEventFilter where this listener matches.
 223 void EventBindings::AttachFilteredEvent(
 224     const v8::FunctionCallbackInfo<v8::Value>& args) {
 225   CHECK_EQ(2, args.Length());
 226   CHECK(args[0]->IsString());
 227   CHECK(args[1]->IsObject());
 228
 229   std::string event_name = *v8::String::Utf8Value(args[0]);
 230
 231   // This method throws an exception if it returns false.
 232   if (!dispatcher_->CheckContextAccessToExtensionAPI(event_name, context()))
 233     return;
 234
 235   std::string extension_id = context()->GetExtensionID();
 236
 237   scoped_ptr<base::DictionaryValue> filter;
 238   scoped_ptr<content::V8ValueConverter> converter(
 239       content::V8ValueConverter::create());
 240
 241   base::DictionaryValue* filter_dict = NULL;
 242   base::Value* filter_value = converter->FromV8Value(
 243       v8::Local<v8::Object>::Cast(args[1]), context()->v8_context());
 244   if (!filter_value) {
 245     args.GetReturnValue().Set(static_cast<int32_t>(-1));
 246     return;
 247   }
 248   if (!filter_value->GetAsDictionary(&filter_dict)) {
 249     delete filter_value;
 250     args.GetReturnValue().Set(static_cast<int32_t>(-1));
 251     return;
 252   }
 253
 254   filter.reset(filter_dict);
 255   EventFilter& event_filter = g_event_filter.Get();
 256   int id =
 257       event_filter.AddEventMatcher(event_name, ParseEventMatcher(filter.get()));
 258
 259   // Only send IPCs the first time a filter gets added.
 260   if (AddFilter(event_name, extension_id, filter.get())) {
 261     bool lazy = IsLazyBackgroundPage(context()->GetRenderView(),
 262                                      context()->extension());
 263     content::RenderThread::Get()->Send(new ExtensionHostMsg_AddFilteredListener(
 264         extension_id, event_name, *filter, lazy));
 265   }
 266
 267   args.GetReturnValue().Set(static_cast<int32_t>(id));
 268 }
 269
 270 void EventBindings::DetachFilteredEvent(
 271     const v8::FunctionCallbackInfo<v8::Value>& args) {
 272   CHECK_EQ(2, args.Length());
 273   CHECK(args[0]->IsInt32());
 274   CHECK(args[1]->IsBoolean());
 275   bool is_manual = args[1]->BooleanValue();
 276
 277   std::string extension_id = context()->GetExtensionID();
 278
 279   int matcher_id = args[0]->Int32Value();
 280   EventFilter& event_filter = g_event_filter.Get();
 281   EventMatcher* event_matcher = event_filter.GetEventMatcher(matcher_id);
 282
 283   const std::string& event_name = event_filter.GetEventName(matcher_id);
 284
 285   // Only send IPCs the last time a filter gets removed.
 286   if (RemoveFilter(event_name, extension_id, event_matcher->value())) {
 287     bool lazy = is_manual && IsLazyBackgroundPage(context()->GetRenderView(),
 288                                                   context()->extension());
 289     content::RenderThread::Get()->Send(
 290         new ExtensionHostMsg_RemoveFilteredListener(
 291             extension_id, event_name, *event_matcher->value(), lazy));
 292   }
 293
 294   event_filter.RemoveEventMatcher(matcher_id);
 295 }
 296
 297 void EventBindings::MatchAgainstEventFilter(
 298     const v8::FunctionCallbackInfo<v8::Value>& args) {
 299   v8::Isolate* isolate = args.GetIsolate();
 300   typedef std::set<EventFilter::MatcherID> MatcherIDs;
 301   EventFilter& event_filter = g_event_filter.Get();
 302   std::string event_name = *v8::String::Utf8Value(args[0]);
 303   EventFilteringInfo info =
 304       ParseFromObject(args[1]->ToObject(isolate), isolate);
 305   // Only match events routed to this context's RenderView or ones that don't
 306   // have a routingId in their filter.
 307   MatcherIDs matched_event_filters = event_filter.MatchEvent(
 308       event_name, info, context()->GetRenderView()->GetRoutingID());
 309   v8::Handle<v8::Array> array(
 310       v8::Array::New(isolate, matched_event_filters.size()));
 311   int i = 0;
 312   for (MatcherIDs::iterator it = matched_event_filters.begin();
 313        it != matched_event_filters.end();
 314        ++it) {
 315     array->Set(v8::Integer::New(isolate, i++), v8::Integer::New(isolate, *it));
 316   }
 317   args.GetReturnValue().Set(array);
 318 }
 319
 320 scoped_ptr<EventMatcher> EventBindings::ParseEventMatcher(
 321     base::DictionaryValue* filter_dict) {
 322   return scoped_ptr<EventMatcher>(new EventMatcher(
 323       scoped_ptr<base::DictionaryValue>(filter_dict->DeepCopy()),
 324       context()->GetRenderView()->GetRoutingID()));
 325 }
 326
 327 }  // namespace extensions