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
   9 #include "base/basictypes.h"
  10 #include "base/bind.h"
  11 #include "base/lazy_instance.h"
  12 #include "base/memory/scoped_ptr.h"
  13 #include "components/crx_file/id_util.h"
  14 #include "content/public/child/v8_value_converter.h"
  15 #include "content/public/renderer/render_thread.h"
  16 #include "content/public/renderer/render_view.h"
  17 #include "extensions/common/event_filter.h"
  18 #include "extensions/common/extension.h"
  19 #include "extensions/common/extension_messages.h"
  20 #include "extensions/common/value_counter.h"
  21 #include "extensions/renderer/extension_frame_helper.h"
  22 #include "extensions/renderer/script_context.h"
  23 #include "url/gurl.h"
  24
  25 namespace extensions {
  26
  27 namespace {
  28
  29 // A map of event names to the number of contexts listening to that event.
  30 // We notify the browser about event listeners when we transition between 0
  31 // and 1.
  32 typedef std::map<std::string, int> EventListenerCounts;
  33
  34 // A map of extension IDs to listener counts for that extension.
  35 base::LazyInstance<std::map<std::string, EventListenerCounts> >
  36     g_listener_counts = LAZY_INSTANCE_INITIALIZER;
  37
  38 // A map of event names to a (filter -> count) map. The map is used to keep
  39 // track of which filters are in effect for which events.
  40 // We notify the browser about filtered event listeners when we transition
  41 // between 0 and 1.
  42 typedef std::map<std::string, linked_ptr<ValueCounter> >
  43     FilteredEventListenerCounts;
  44
  45 // A map of extension IDs to filtered listener counts for that extension.
  46 base::LazyInstance<std::map<std::string, FilteredEventListenerCounts> >
  47     g_filtered_listener_counts = LAZY_INSTANCE_INITIALIZER;
  48
  49 base::LazyInstance<EventFilter> g_event_filter = LAZY_INSTANCE_INITIALIZER;
  50
  51 std::string GetKeyForScriptContext(ScriptContext* script_context) {
  52   const std::string& extension_id = script_context->GetExtensionID();
  53   CHECK(crx_file::id_util::IdIsValid(extension_id) ||
  54         script_context->GetURL().is_valid());
  55   return crx_file::id_util::IdIsValid(extension_id)
  56              ? extension_id
  57              : script_context->GetURL().spec();
  58 }
  59
  60 // Increments the number of event-listeners for the given |event_name| and
  61 // ScriptContext. Returns the count after the increment.
  62 int IncrementEventListenerCount(ScriptContext* script_context,
  63                                 const std::string& event_name) {
  64   return ++g_listener_counts
  65                .Get()[GetKeyForScriptContext(script_context)][event_name];
  66 }
  67
  68 // Decrements the number of event-listeners for the given |event_name| and
  69 // ScriptContext. Returns the count after the increment.
  70 int DecrementEventListenerCount(ScriptContext* script_context,
  71                                 const std::string& event_name) {
  72   return --g_listener_counts
  73                .Get()[GetKeyForScriptContext(script_context)][event_name];
  74 }
  75
  76 EventFilteringInfo ParseFromObject(v8::Local<v8::Object> object,
  77                                    v8::Isolate* isolate) {
  78   EventFilteringInfo info;
  79   v8::Local<v8::String> url(v8::String::NewFromUtf8(isolate, "url"));
  80   if (object->Has(url)) {
  81     v8::Local<v8::Value> url_value(object->Get(url));
  82     info.SetURL(GURL(*v8::String::Utf8Value(url_value)));
  83   }
  84   v8::Local<v8::String> instance_id(
  85       v8::String::NewFromUtf8(isolate, "instanceId"));
  86   if (object->Has(instance_id)) {
  87     v8::Local<v8::Value> instance_id_value(object->Get(instance_id));
  88     info.SetInstanceID(instance_id_value->IntegerValue());
  89   }
  90   v8::Local<v8::String> service_type(
  91       v8::String::NewFromUtf8(isolate, "serviceType"));
  92   if (object->Has(service_type)) {
  93     v8::Local<v8::Value> service_type_value(object->Get(service_type));
  94     info.SetServiceType(*v8::String::Utf8Value(service_type_value));
  95   }
  96   return info;
  97 }
  98
  99 // Add a filter to |event_name| in |extension_id|, returning true if it
 100 // was the first filter for that event in that extension.
 101 bool AddFilter(const std::string& event_name,
 102                const std::string& extension_id,
 103                base::DictionaryValue* filter) {
 104   FilteredEventListenerCounts& counts =
 105       g_filtered_listener_counts.Get()[extension_id];
 106   FilteredEventListenerCounts::iterator it = counts.find(event_name);
 107   if (it == counts.end())
 108     counts[event_name].reset(new ValueCounter);
 109
 110   int result = counts[event_name]->Add(*filter);
 111   return 1 == result;
 112 }
 113
 114 // Remove a filter from |event_name| in |extension_id|, returning true if it
 115 // was the last filter for that event in that extension.
 116 bool RemoveFilter(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     return false;
 124   return 0 == it->second->Remove(*filter);
 125 }
 126
 127 }  // namespace
 128
 129 EventBindings::EventBindings(ScriptContext* context)
 130     : ObjectBackedNativeHandler(context) {
 131   RouteFunction("AttachEvent", base::Bind(&EventBindings::AttachEventHandler,
 132                                           base::Unretained(this)));
 133   RouteFunction("DetachEvent", base::Bind(&EventBindings::DetachEventHandler,
 134                                           base::Unretained(this)));
 135   RouteFunction(
 136       "AttachFilteredEvent",
 137       base::Bind(&EventBindings::AttachFilteredEvent, base::Unretained(this)));
 138   RouteFunction(
 139       "DetachFilteredEvent",
 140       base::Bind(&EventBindings::DetachFilteredEvent, base::Unretained(this)));
 141   RouteFunction("MatchAgainstEventFilter",
 142                 base::Bind(&EventBindings::MatchAgainstEventFilter,
 143                            base::Unretained(this)));
 144
 145   // It's safe to use base::Unretained here because |context| will always
 146   // outlive us.
 147   context->AddInvalidationObserver(
 148       base::Bind(&EventBindings::OnInvalidated, base::Unretained(this)));
 149 }
 150
 151 EventBindings::~EventBindings() {}
 152
 153 void EventBindings::AttachEventHandler(
 154     const v8::FunctionCallbackInfo<v8::Value>& args) {
 155   CHECK_EQ(1, args.Length());
 156   CHECK(args[0]->IsString());
 157   AttachEvent(*v8::String::Utf8Value(args[0]));
 158 }
 159
 160 void EventBindings::AttachEvent(const std::string& event_name) {
 161   if (!context()->HasAccessOrThrowError(event_name))
 162     return;
 163
 164   // Record the attachment for this context so that events can be detached when
 165   // the context is destroyed.
 166   //
 167   // Ideally we'd CHECK that it's not already attached, however that's not
 168   // possible because extensions can create and attach events themselves. Very
 169   // silly, but that's the way it is. For an example of this, see
 170   // chrome/test/data/extensions/api_test/events/background.js.
 171   attached_event_names_.insert(event_name);
 172
 173   const std::string& extension_id = context()->GetExtensionID();
 174   if (IncrementEventListenerCount(context(), event_name) == 1) {
 175     content::RenderThread::Get()->Send(new ExtensionHostMsg_AddListener(
 176         extension_id, context()->GetURL(), event_name));
 177   }
 178
 179   // This is called the first time the page has added a listener. Since
 180   // the background page is the only lazy page, we know this is the first
 181   // time this listener has been registered.
 182   if (ExtensionFrameHelper::IsContextForEventPage(context())) {
 183     content::RenderThread::Get()->Send(
 184         new ExtensionHostMsg_AddLazyListener(extension_id, event_name));
 185   }
 186 }
 187
 188 void EventBindings::DetachEventHandler(
 189     const v8::FunctionCallbackInfo<v8::Value>& args) {
 190   CHECK_EQ(2, args.Length());
 191   CHECK(args[0]->IsString());
 192   CHECK(args[1]->IsBoolean());
 193   DetachEvent(*v8::String::Utf8Value(args[0]), args[1]->BooleanValue());
 194 }
 195
 196 void EventBindings::DetachEvent(const std::string& event_name, bool is_manual) {
 197   // See comment in AttachEvent().
 198   attached_event_names_.erase(event_name);
 199
 200   const std::string& extension_id = context()->GetExtensionID();
 201
 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 && ExtensionFrameHelper::IsContextForEventPage(context())) {
 212     content::RenderThread::Get()->Send(
 213         new ExtensionHostMsg_RemoveLazyListener(extension_id, event_name));
 214   }
 215 }
 216
 217 // MatcherID AttachFilteredEvent(string event_name, object filter)
 218 // event_name - Name of the event to attach.
 219 // filter - Which instances of the named event are we interested in.
 220 // returns the id assigned to the listener, which will be returned from calls
 221 // to MatchAgainstEventFilter where this listener matches.
 222 void EventBindings::AttachFilteredEvent(
 223     const v8::FunctionCallbackInfo<v8::Value>& args) {
 224   CHECK_EQ(2, args.Length());
 225   CHECK(args[0]->IsString());
 226   CHECK(args[1]->IsObject());
 227
 228   std::string event_name = *v8::String::Utf8Value(args[0]);
 229   if (!context()->HasAccessOrThrowError(event_name))
 230     return;
 231
 232   std::string extension_id = context()->GetExtensionID();
 233
 234   scoped_ptr<base::DictionaryValue> filter;
 235   scoped_ptr<content::V8ValueConverter> converter(
 236       content::V8ValueConverter::create());
 237
 238   base::DictionaryValue* filter_dict = NULL;
 239   base::Value* filter_value = converter->FromV8Value(
 240       v8::Local<v8::Object>::Cast(args[1]), context()->v8_context());
 241   if (!filter_value) {
 242     args.GetReturnValue().Set(static_cast<int32_t>(-1));
 243     return;
 244   }
 245   if (!filter_value->GetAsDictionary(&filter_dict)) {
 246     delete filter_value;
 247     args.GetReturnValue().Set(static_cast<int32_t>(-1));
 248     return;
 249   }
 250
 251   filter.reset(filter_dict);
 252   EventFilter& event_filter = g_event_filter.Get();
 253   int id =
 254       event_filter.AddEventMatcher(event_name, ParseEventMatcher(filter.get()));
 255
 256   // Only send IPCs the first time a filter gets added.
 257   if (AddFilter(event_name, extension_id, filter.get())) {
 258     bool lazy = ExtensionFrameHelper::IsContextForEventPage(context());
 259     content::RenderThread::Get()->Send(new ExtensionHostMsg_AddFilteredListener(
 260         extension_id, event_name, *filter, lazy));
 261   }
 262
 263   args.GetReturnValue().Set(static_cast<int32_t>(id));
 264 }
 265
 266 void EventBindings::DetachFilteredEvent(
 267     const v8::FunctionCallbackInfo<v8::Value>& args) {
 268   CHECK_EQ(2, args.Length());
 269   CHECK(args[0]->IsInt32());
 270   CHECK(args[1]->IsBoolean());
 271   bool is_manual = args[1]->BooleanValue();
 272
 273   std::string extension_id = context()->GetExtensionID();
 274
 275   int matcher_id = args[0]->Int32Value();
 276   EventFilter& event_filter = g_event_filter.Get();
 277   EventMatcher* event_matcher = event_filter.GetEventMatcher(matcher_id);
 278
 279   const std::string& event_name = event_filter.GetEventName(matcher_id);
 280
 281   // Only send IPCs the last time a filter gets removed.
 282   if (RemoveFilter(event_name, extension_id, event_matcher->value())) {
 283     bool remove_lazy =
 284         is_manual && ExtensionFrameHelper::IsContextForEventPage(context());
 285     content::RenderThread::Get()->Send(
 286         new ExtensionHostMsg_RemoveFilteredListener(
 287             extension_id, event_name, *event_matcher->value(), remove_lazy));
 288   }
 289
 290   event_filter.RemoveEventMatcher(matcher_id);
 291 }
 292
 293 void EventBindings::MatchAgainstEventFilter(
 294     const v8::FunctionCallbackInfo<v8::Value>& args) {
 295   v8::Isolate* isolate = args.GetIsolate();
 296   typedef std::set<EventFilter::MatcherID> MatcherIDs;
 297   EventFilter& event_filter = g_event_filter.Get();
 298   std::string event_name = *v8::String::Utf8Value(args[0]);
 299   EventFilteringInfo info =
 300       ParseFromObject(args[1]->ToObject(isolate), isolate);
 301   // Only match events routed to this context's RenderView or ones that don't
 302   // have a routingId in their filter.
 303   MatcherIDs matched_event_filters = event_filter.MatchEvent(
 304       event_name, info, context()->GetRenderView()->GetRoutingID());
 305   v8::Local<v8::Array> array(
 306       v8::Array::New(isolate, matched_event_filters.size()));
 307   int i = 0;
 308   for (MatcherIDs::iterator it = matched_event_filters.begin();
 309        it != matched_event_filters.end();
 310        ++it) {
 311     array->Set(v8::Integer::New(isolate, i++), v8::Integer::New(isolate, *it));
 312   }
 313   args.GetReturnValue().Set(array);
 314 }
 315
 316 scoped_ptr<EventMatcher> EventBindings::ParseEventMatcher(
 317     base::DictionaryValue* filter_dict) {
 318   return scoped_ptr<EventMatcher>(new EventMatcher(
 319       scoped_ptr<base::DictionaryValue>(filter_dict->DeepCopy()),
 320       context()->GetRenderView()->GetRoutingID()));
 321 }
 322
 323 void EventBindings::OnInvalidated() {
 324   // Detach all attached events that weren't attached. Iterate over a copy
 325   // because it will be mutated.
 326   std::set<std::string> attached_event_names_safe = attached_event_names_;
 327   for (const std::string& event_name : attached_event_names_safe) {
 328     DetachEvent(event_name, false /* is_manual */);
 329   }
 330   DCHECK(attached_event_names_.empty())
 331       << "Events cannot be attached during invalidation";
 332 }
 333
 334 }  // namespace extensions