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/manifest_handlers/background_info.h"
  21 #include "extensions/common/value_counter.h"
  22 #include "extensions/renderer/extension_helper.h"
  23 #include "extensions/renderer/script_context.h"
  24 #include "url/gurl.h"
  25
  26 namespace extensions {
  27
  28 namespace {
  29
  30 // A map of event names to the number of contexts listening to that event.
  31 // We notify the browser about event listeners when we transition between 0
  32 // and 1.
  33 typedef std::map<std::string, int> EventListenerCounts;
  34
  35 // A map of extension IDs to listener counts for that extension.
  36 base::LazyInstance<std::map<std::string, EventListenerCounts> >
  37     g_listener_counts = LAZY_INSTANCE_INITIALIZER;
  38
  39 // A map of event names to a (filter -> count) map. The map is used to keep
  40 // track of which filters are in effect for which events.
  41 // We notify the browser about filtered event listeners when we transition
  42 // between 0 and 1.
  43 typedef std::map<std::string, linked_ptr<ValueCounter> >
  44     FilteredEventListenerCounts;
  45
  46 // A map of extension IDs to filtered listener counts for that extension.
  47 base::LazyInstance<std::map<std::string, FilteredEventListenerCounts> >
  48     g_filtered_listener_counts = LAZY_INSTANCE_INITIALIZER;
  49
  50 base::LazyInstance<EventFilter> g_event_filter = LAZY_INSTANCE_INITIALIZER;
  51
  52 std::string GetKeyForScriptContext(ScriptContext* script_context) {
  53   const std::string& extension_id = script_context->GetExtensionID();
  54   CHECK(crx_file::id_util::IdIsValid(extension_id) ||
  55         script_context->GetURL().is_valid());
  56   return crx_file::id_util::IdIsValid(extension_id)
  57              ? extension_id
  58              : script_context->GetURL().spec();
  59 }
  60
  61 // Increments the number of event-listeners for the given |event_name| and
  62 // ScriptContext. Returns the count after the increment.
  63 int IncrementEventListenerCount(ScriptContext* script_context,
  64                                 const std::string& event_name) {
  65   return ++g_listener_counts
  66                .Get()[GetKeyForScriptContext(script_context)][event_name];
  67 }
  68
  69 // Decrements the number of event-listeners for the given |event_name| and
  70 // ScriptContext. Returns the count after the increment.
  71 int DecrementEventListenerCount(ScriptContext* script_context,
  72                                 const std::string& event_name) {
  73   return --g_listener_counts
  74                .Get()[GetKeyForScriptContext(script_context)][event_name];
  75 }
  76
  77 bool IsLazyBackgroundPage(content::RenderView* render_view,
  78                           const Extension* extension) {
  79   if (!render_view)
  80     return false;
  81   ExtensionHelper* helper = ExtensionHelper::Get(render_view);
  82   return (extension && BackgroundInfo::HasLazyBackgroundPage(extension) &&
  83           helper->view_type() == VIEW_TYPE_EXTENSION_BACKGROUND_PAGE);
  84 }
  85
  86 EventFilteringInfo ParseFromObject(v8::Local<v8::Object> object,
  87                                    v8::Isolate* isolate) {
  88   EventFilteringInfo info;
  89   v8::Local<v8::String> url(v8::String::NewFromUtf8(isolate, "url"));
  90   if (object->Has(url)) {
  91     v8::Local<v8::Value> url_value(object->Get(url));
  92     info.SetURL(GURL(*v8::String::Utf8Value(url_value)));
  93   }
  94   v8::Local<v8::String> instance_id(
  95       v8::String::NewFromUtf8(isolate, "instanceId"));
  96   if (object->Has(instance_id)) {
  97     v8::Local<v8::Value> instance_id_value(object->Get(instance_id));
  98     info.SetInstanceID(instance_id_value->IntegerValue());
  99   }
 100   v8::Local<v8::String> service_type(
 101       v8::String::NewFromUtf8(isolate, "serviceType"));
 102   if (object->Has(service_type)) {
 103     v8::Local<v8::Value> service_type_value(object->Get(service_type));
 104     info.SetServiceType(*v8::String::Utf8Value(service_type_value));
 105   }
 106   return info;
 107 }
 108
 109 // Add a filter to |event_name| in |extension_id|, returning true if it
 110 // was the first filter for that event in that extension.
 111 bool AddFilter(const std::string& event_name,
 112                const std::string& extension_id,
 113                base::DictionaryValue* filter) {
 114   FilteredEventListenerCounts& counts =
 115       g_filtered_listener_counts.Get()[extension_id];
 116   FilteredEventListenerCounts::iterator it = counts.find(event_name);
 117   if (it == counts.end())
 118     counts[event_name].reset(new ValueCounter);
 119
 120   int result = counts[event_name]->Add(*filter);
 121   return 1 == result;
 122 }
 123
 124 // Remove a filter from |event_name| in |extension_id|, returning true if it
 125 // was the last filter for that event in that extension.
 126 bool RemoveFilter(const std::string& event_name,
 127                   const std::string& extension_id,
 128                   base::DictionaryValue* filter) {
 129   FilteredEventListenerCounts& counts =
 130       g_filtered_listener_counts.Get()[extension_id];
 131   FilteredEventListenerCounts::iterator it = counts.find(event_name);
 132   if (it == counts.end())
 133     return false;
 134   return 0 == it->second->Remove(*filter);
 135 }
 136
 137 }  // namespace
 138
 139 EventBindings::EventBindings(ScriptContext* context)
 140     : ObjectBackedNativeHandler(context) {
 141   RouteFunction("AttachEvent", base::Bind(&EventBindings::AttachEventHandler,
 142                                           base::Unretained(this)));
 143   RouteFunction("DetachEvent", base::Bind(&EventBindings::DetachEventHandler,
 144                                           base::Unretained(this)));
 145   RouteFunction(
 146       "AttachFilteredEvent",
 147       base::Bind(&EventBindings::AttachFilteredEvent, base::Unretained(this)));
 148   RouteFunction(
 149       "DetachFilteredEvent",
 150       base::Bind(&EventBindings::DetachFilteredEvent, base::Unretained(this)));
 151   RouteFunction("MatchAgainstEventFilter",
 152                 base::Bind(&EventBindings::MatchAgainstEventFilter,
 153                            base::Unretained(this)));
 154
 155   // It's safe to use base::Unretained here because |context| will always
 156   // outlive us.
 157   context->AddInvalidationObserver(
 158       base::Bind(&EventBindings::OnInvalidated, base::Unretained(this)));
 159 }
 160
 161 EventBindings::~EventBindings() {}
 162
 163 void EventBindings::AttachEventHandler(
 164     const v8::FunctionCallbackInfo<v8::Value>& args) {
 165   CHECK_EQ(1, args.Length());
 166   CHECK(args[0]->IsString());
 167   AttachEvent(*v8::String::Utf8Value(args[0]));
 168 }
 169
 170 void EventBindings::AttachEvent(const std::string& event_name) {
 171   if (!context()->HasAccessOrThrowError(event_name))
 172     return;
 173
 174   // Record the attachment for this context so that events can be detached when
 175   // the context is destroyed.
 176   //
 177   // Ideally we'd CHECK that it's not already attached, however that's not
 178   // possible because extensions can create and attach events themselves. Very
 179   // silly, but that's the way it is. For an example of this, see
 180   // chrome/test/data/extensions/api_test/events/background.js.
 181   attached_event_names_.insert(event_name);
 182
 183   const std::string& extension_id = context()->GetExtensionID();
 184   if (IncrementEventListenerCount(context(), event_name) == 1) {
 185     content::RenderThread::Get()->Send(new ExtensionHostMsg_AddListener(
 186         extension_id, context()->GetURL(), event_name));
 187   }
 188
 189   // This is called the first time the page has added a listener. Since
 190   // the background page is the only lazy page, we know this is the first
 191   // time this listener has been registered.
 192   if (IsLazyBackgroundPage(context()->GetRenderView(),
 193                            context()->extension())) {
 194     content::RenderThread::Get()->Send(
 195         new ExtensionHostMsg_AddLazyListener(extension_id, event_name));
 196   }
 197 }
 198
 199 void EventBindings::DetachEventHandler(
 200     const v8::FunctionCallbackInfo<v8::Value>& args) {
 201   CHECK_EQ(2, args.Length());
 202   CHECK(args[0]->IsString());
 203   CHECK(args[1]->IsBoolean());
 204   DetachEvent(*v8::String::Utf8Value(args[0]), args[1]->BooleanValue());
 205 }
 206
 207 void EventBindings::DetachEvent(const std::string& event_name, bool is_manual) {
 208   // See comment in AttachEvent().
 209   attached_event_names_.erase(event_name);
 210
 211   const std::string& extension_id = context()->GetExtensionID();
 212
 213   if (DecrementEventListenerCount(context(), event_name) == 0) {
 214     content::RenderThread::Get()->Send(new ExtensionHostMsg_RemoveListener(
 215         extension_id, context()->GetURL(), event_name));
 216   }
 217
 218   // DetachEvent is called when the last listener for the context is
 219   // removed. If the context is the background page, and it removes the
 220   // last listener manually, then we assume that it is no longer interested
 221   // in being awakened for this event.
 222   if (is_manual && IsLazyBackgroundPage(context()->GetRenderView(),
 223                                         context()->extension())) {
 224     content::RenderThread::Get()->Send(
 225         new ExtensionHostMsg_RemoveLazyListener(extension_id, event_name));
 226   }
 227 }
 228
 229 // MatcherID AttachFilteredEvent(string event_name, object filter)
 230 // event_name - Name of the event to attach.
 231 // filter - Which instances of the named event are we interested in.
 232 // returns the id assigned to the listener, which will be returned from calls
 233 // to MatchAgainstEventFilter where this listener matches.
 234 void EventBindings::AttachFilteredEvent(
 235     const v8::FunctionCallbackInfo<v8::Value>& args) {
 236   CHECK_EQ(2, args.Length());
 237   CHECK(args[0]->IsString());
 238   CHECK(args[1]->IsObject());
 239
 240   std::string event_name = *v8::String::Utf8Value(args[0]);
 241   if (!context()->HasAccessOrThrowError(event_name))
 242     return;
 243
 244   std::string extension_id = context()->GetExtensionID();
 245
 246   scoped_ptr<base::DictionaryValue> filter;
 247   scoped_ptr<content::V8ValueConverter> converter(
 248       content::V8ValueConverter::create());
 249
 250   base::DictionaryValue* filter_dict = NULL;
 251   base::Value* filter_value = converter->FromV8Value(
 252       v8::Local<v8::Object>::Cast(args[1]), context()->v8_context());
 253   if (!filter_value) {
 254     args.GetReturnValue().Set(static_cast<int32_t>(-1));
 255     return;
 256   }
 257   if (!filter_value->GetAsDictionary(&filter_dict)) {
 258     delete filter_value;
 259     args.GetReturnValue().Set(static_cast<int32_t>(-1));
 260     return;
 261   }
 262
 263   filter.reset(filter_dict);
 264   EventFilter& event_filter = g_event_filter.Get();
 265   int id =
 266       event_filter.AddEventMatcher(event_name, ParseEventMatcher(filter.get()));
 267
 268   // Only send IPCs the first time a filter gets added.
 269   if (AddFilter(event_name, extension_id, filter.get())) {
 270     bool lazy = IsLazyBackgroundPage(context()->GetRenderView(),
 271                                      context()->extension());
 272     content::RenderThread::Get()->Send(new ExtensionHostMsg_AddFilteredListener(
 273         extension_id, event_name, *filter, lazy));
 274   }
 275
 276   args.GetReturnValue().Set(static_cast<int32_t>(id));
 277 }
 278
 279 void EventBindings::DetachFilteredEvent(
 280     const v8::FunctionCallbackInfo<v8::Value>& args) {
 281   CHECK_EQ(2, args.Length());
 282   CHECK(args[0]->IsInt32());
 283   CHECK(args[1]->IsBoolean());
 284   bool is_manual = args[1]->BooleanValue();
 285
 286   std::string extension_id = context()->GetExtensionID();
 287
 288   int matcher_id = args[0]->Int32Value();
 289   EventFilter& event_filter = g_event_filter.Get();
 290   EventMatcher* event_matcher = event_filter.GetEventMatcher(matcher_id);
 291
 292   const std::string& event_name = event_filter.GetEventName(matcher_id);
 293
 294   // Only send IPCs the last time a filter gets removed.
 295   if (RemoveFilter(event_name, extension_id, event_matcher->value())) {
 296     bool lazy = is_manual && IsLazyBackgroundPage(context()->GetRenderView(),
 297                                                   context()->extension());
 298     content::RenderThread::Get()->Send(
 299         new ExtensionHostMsg_RemoveFilteredListener(
 300             extension_id, event_name, *event_matcher->value(), lazy));
 301   }
 302
 303   event_filter.RemoveEventMatcher(matcher_id);
 304 }
 305
 306 void EventBindings::MatchAgainstEventFilter(
 307     const v8::FunctionCallbackInfo<v8::Value>& args) {
 308   v8::Isolate* isolate = args.GetIsolate();
 309   typedef std::set<EventFilter::MatcherID> MatcherIDs;
 310   EventFilter& event_filter = g_event_filter.Get();
 311   std::string event_name = *v8::String::Utf8Value(args[0]);
 312   EventFilteringInfo info =
 313       ParseFromObject(args[1]->ToObject(isolate), isolate);
 314   // Only match events routed to this context's RenderView or ones that don't
 315   // have a routingId in their filter.
 316   MatcherIDs matched_event_filters = event_filter.MatchEvent(
 317       event_name, info, context()->GetRenderView()->GetRoutingID());
 318   v8::Local<v8::Array> array(
 319       v8::Array::New(isolate, matched_event_filters.size()));
 320   int i = 0;
 321   for (MatcherIDs::iterator it = matched_event_filters.begin();
 322        it != matched_event_filters.end();
 323        ++it) {
 324     array->Set(v8::Integer::New(isolate, i++), v8::Integer::New(isolate, *it));
 325   }
 326   args.GetReturnValue().Set(array);
 327 }
 328
 329 scoped_ptr<EventMatcher> EventBindings::ParseEventMatcher(
 330     base::DictionaryValue* filter_dict) {
 331   return scoped_ptr<EventMatcher>(new EventMatcher(
 332       scoped_ptr<base::DictionaryValue>(filter_dict->DeepCopy()),
 333       context()->GetRenderView()->GetRoutingID()));
 334 }
 335
 336 void EventBindings::OnInvalidated() {
 337   // Detach all attached events that weren't attached. Iterate over a copy
 338   // because it will be mutated.
 339   std::set<std::string> attached_event_names_safe = attached_event_names_;
 340   for (const std::string& event_name : attached_event_names_safe) {
 341     DetachEvent(event_name, false /* is_manual */);
 342   }
 343   DCHECK(attached_event_names_.empty())
 344       << "Events cannot be attached during invalidation";
 345 }
 346
 347 }  // namespace extensions