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 <utility>
   9
  10 #include "base/basictypes.h"
  11 #include "base/bind.h"
  12 #include "base/containers/scoped_ptr_map.h"
  13 #include "base/lazy_instance.h"
  14 #include "base/memory/scoped_ptr.h"
  15 #include "components/crx_file/id_util.h"
  16 #include "content/public/child/v8_value_converter.h"
  17 #include "content/public/renderer/render_frame.h"
  18 #include "content/public/renderer/render_thread.h"
  19 #include "content/public/renderer/render_view.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/value_counter.h"
  24 #include "extensions/renderer/extension_frame_helper.h"
  25 #include "extensions/renderer/script_context.h"
  26 #include "url/gurl.h"
  27
  28 namespace extensions {
  29
  30 namespace {
  31
  32 // A map of event names to the number of contexts listening to that event.
  33 // We notify the browser about event listeners when we transition between 0
  34 // and 1.
  35 typedef std::map<std::string, int> EventListenerCounts;
  36
  37 // A map of extension IDs to listener counts for that extension.
  38 base::LazyInstance<std::map<std::string, EventListenerCounts>>
  39     g_listener_counts = LAZY_INSTANCE_INITIALIZER;
  40
  41 // A map of (extension ID, event name) pairs to the filtered listener counts
  42 // for that pair. The map is used to keep track of which filters are in effect
  43 // for which events.  We notify the browser about filtered event listeners when
  44 // we transition between 0 and 1.
  45 using FilteredEventListenerKey = std::pair<std::string, std::string>;
  46 using FilteredEventListenerCounts =
  47     base::ScopedPtrMap<FilteredEventListenerKey, scoped_ptr<ValueCounter>>;
  48 base::LazyInstance<FilteredEventListenerCounts> g_filtered_listener_counts =
  49     LAZY_INSTANCE_INITIALIZER;
  50
  51 base::LazyInstance<EventFilter> g_event_filter = LAZY_INSTANCE_INITIALIZER;
  52
  53 // Gets a unique string key identifier for a ScriptContext.
  54 // TODO(kalman): Just use pointer equality...?
  55 std::string GetKeyForScriptContext(ScriptContext* script_context) {
  56   const std::string& extension_id = script_context->GetExtensionID();
  57   CHECK(crx_file::id_util::IdIsValid(extension_id) ||
  58         script_context->GetURL().is_valid());
  59   return crx_file::id_util::IdIsValid(extension_id)
  60              ? extension_id
  61              : script_context->GetURL().spec();
  62 }
  63
  64 // Increments the number of event-listeners for the given |event_name| and
  65 // ScriptContext. Returns the count after the increment.
  66 int IncrementEventListenerCount(ScriptContext* script_context,
  67                                 const std::string& event_name) {
  68   return ++g_listener_counts
  69                .Get()[GetKeyForScriptContext(script_context)][event_name];
  70 }
  71
  72 // Decrements the number of event-listeners for the given |event_name| and
  73 // ScriptContext. Returns the count after the increment.
  74 int DecrementEventListenerCount(ScriptContext* script_context,
  75                                 const std::string& event_name) {
  76   return --g_listener_counts
  77                .Get()[GetKeyForScriptContext(script_context)][event_name];
  78 }
  79
  80 EventFilteringInfo ParseFromObject(v8::Local<v8::Object> object,
  81                                    v8::Isolate* isolate) {
  82   EventFilteringInfo info;
  83   v8::Local<v8::String> url(v8::String::NewFromUtf8(isolate, "url"));
  84   if (object->Has(url)) {
  85     v8::Local<v8::Value> url_value(object->Get(url));
  86     info.SetURL(GURL(*v8::String::Utf8Value(url_value)));
  87   }
  88   v8::Local<v8::String> instance_id(
  89       v8::String::NewFromUtf8(isolate, "instanceId"));
  90   if (object->Has(instance_id)) {
  91     v8::Local<v8::Value> instance_id_value(object->Get(instance_id));
  92     info.SetInstanceID(instance_id_value->IntegerValue());
  93   }
  94   v8::Local<v8::String> service_type(
  95       v8::String::NewFromUtf8(isolate, "serviceType"));
  96   if (object->Has(service_type)) {
  97     v8::Local<v8::Value> service_type_value(object->Get(service_type));
  98     info.SetServiceType(*v8::String::Utf8Value(service_type_value));
  99   }
 100   v8::Local<v8::String> window_types(
 101       v8::String::NewFromUtf8(isolate, "windowType"));
 102   if (object->Has(window_types)) {
 103     v8::Local<v8::Value> window_types_value(object->Get(window_types));
 104     info.SetWindowType(*v8::String::Utf8Value(window_types_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                const base::DictionaryValue& filter) {
 114   FilteredEventListenerKey key(extension_id, event_name);
 115   FilteredEventListenerCounts& all_counts = g_filtered_listener_counts.Get();
 116   FilteredEventListenerCounts::const_iterator counts = all_counts.find(key);
 117   if (counts == all_counts.end()) {
 118     counts = all_counts.insert(key, make_scoped_ptr(new ValueCounter())).first;
 119   }
 120   return counts->second->Add(filter);
 121 }
 122
 123 // Remove a filter from |event_name| in |extension_id|, returning true if it
 124 // was the last filter for that event in that extension.
 125 bool RemoveFilter(const std::string& event_name,
 126                   const std::string& extension_id,
 127                   base::DictionaryValue* filter) {
 128   FilteredEventListenerKey key(extension_id, event_name);
 129   FilteredEventListenerCounts& all_counts = g_filtered_listener_counts.Get();
 130   FilteredEventListenerCounts::const_iterator counts = all_counts.find(key);
 131   if (counts == all_counts.end())
 132     return false;
 133   // Note: Remove() returns true if it removed the last filter equivalent to
 134   // |filter|. If there are more equivalent filters, or if there weren't any in
 135   // the first place, it returns false.
 136   if (counts->second->Remove(*filter)) {
 137     if (counts->second->is_empty())
 138       all_counts.erase(counts);  // Clean up if there are no more filters.
 139     return true;
 140   }
 141   return false;
 142 }
 143
 144 }  // namespace
 145
 146 EventBindings::EventBindings(ScriptContext* context)
 147     : ObjectBackedNativeHandler(context) {
 148   RouteFunction("AttachEvent", base::Bind(&EventBindings::AttachEventHandler,
 149                                           base::Unretained(this)));
 150   RouteFunction("DetachEvent", base::Bind(&EventBindings::DetachEventHandler,
 151                                           base::Unretained(this)));
 152   RouteFunction(
 153       "AttachFilteredEvent",
 154       base::Bind(&EventBindings::AttachFilteredEvent, base::Unretained(this)));
 155   RouteFunction("DetachFilteredEvent",
 156                 base::Bind(&EventBindings::DetachFilteredEventHandler,
 157                            base::Unretained(this)));
 158   RouteFunction("MatchAgainstEventFilter",
 159                 base::Bind(&EventBindings::MatchAgainstEventFilter,
 160                            base::Unretained(this)));
 161
 162   // It's safe to use base::Unretained here because |context| will always
 163   // outlive us.
 164   context->AddInvalidationObserver(
 165       base::Bind(&EventBindings::OnInvalidated, base::Unretained(this)));
 166 }
 167
 168 EventBindings::~EventBindings() {}
 169
 170 void EventBindings::AttachEventHandler(
 171     const v8::FunctionCallbackInfo<v8::Value>& args) {
 172   CHECK_EQ(1, args.Length());
 173   CHECK(args[0]->IsString());
 174   AttachEvent(*v8::String::Utf8Value(args[0]));
 175 }
 176
 177 void EventBindings::AttachEvent(const std::string& event_name) {
 178   if (!context()->HasAccessOrThrowError(event_name))
 179     return;
 180
 181   // Record the attachment for this context so that events can be detached when
 182   // the context is destroyed.
 183   //
 184   // Ideally we'd CHECK that it's not already attached, however that's not
 185   // possible because extensions can create and attach events themselves. Very
 186   // silly, but that's the way it is. For an example of this, see
 187   // chrome/test/data/extensions/api_test/events/background.js.
 188   attached_event_names_.insert(event_name);
 189
 190   const std::string& extension_id = context()->GetExtensionID();
 191   if (IncrementEventListenerCount(context(), event_name) == 1) {
 192     content::RenderThread::Get()->Send(new ExtensionHostMsg_AddListener(
 193         extension_id, context()->GetURL(), event_name));
 194   }
 195
 196   // This is called the first time the page has added a listener. Since
 197   // the background page is the only lazy page, we know this is the first
 198   // time this listener has been registered.
 199   if (ExtensionFrameHelper::IsContextForEventPage(context())) {
 200     content::RenderThread::Get()->Send(
 201         new ExtensionHostMsg_AddLazyListener(extension_id, event_name));
 202   }
 203 }
 204
 205 void EventBindings::DetachEventHandler(
 206     const v8::FunctionCallbackInfo<v8::Value>& args) {
 207   CHECK_EQ(2, args.Length());
 208   CHECK(args[0]->IsString());
 209   CHECK(args[1]->IsBoolean());
 210   DetachEvent(*v8::String::Utf8Value(args[0]), args[1]->BooleanValue());
 211 }
 212
 213 void EventBindings::DetachEvent(const std::string& event_name, bool is_manual) {
 214   // See comment in AttachEvent().
 215   attached_event_names_.erase(event_name);
 216
 217   const std::string& extension_id = context()->GetExtensionID();
 218
 219   if (DecrementEventListenerCount(context(), event_name) == 0) {
 220     content::RenderThread::Get()->Send(new ExtensionHostMsg_RemoveListener(
 221         extension_id, context()->GetURL(), event_name));
 222   }
 223
 224   // DetachEvent is called when the last listener for the context is
 225   // removed. If the context is the background page, and it removes the
 226   // last listener manually, then we assume that it is no longer interested
 227   // in being awakened for this event.
 228   if (is_manual && ExtensionFrameHelper::IsContextForEventPage(context())) {
 229     content::RenderThread::Get()->Send(
 230         new ExtensionHostMsg_RemoveLazyListener(extension_id, event_name));
 231   }
 232 }
 233
 234 // MatcherID AttachFilteredEvent(string event_name, object filter)
 235 // event_name - Name of the event to attach.
 236 // filter - Which instances of the named event are we interested in.
 237 // returns the id assigned to the listener, which will be returned from calls
 238 // to MatchAgainstEventFilter where this listener matches.
 239 void EventBindings::AttachFilteredEvent(
 240     const v8::FunctionCallbackInfo<v8::Value>& args) {
 241   CHECK_EQ(2, args.Length());
 242   CHECK(args[0]->IsString());
 243   CHECK(args[1]->IsObject());
 244
 245   std::string event_name = *v8::String::Utf8Value(args[0]);
 246   if (!context()->HasAccessOrThrowError(event_name))
 247     return;
 248
 249   scoped_ptr<base::DictionaryValue> filter;
 250   {
 251     scoped_ptr<content::V8ValueConverter> converter(
 252         content::V8ValueConverter::create());
 253     scoped_ptr<base::Value> filter_value(converter->FromV8Value(
 254         v8::Local<v8::Object>::Cast(args[1]), context()->v8_context()));
 255     if (!filter_value || !filter_value->IsType(base::Value::TYPE_DICTIONARY)) {
 256       args.GetReturnValue().Set(static_cast<int32_t>(-1));
 257       return;
 258     }
 259     filter.reset(static_cast<base::DictionaryValue*>(filter_value.release()));
 260   }
 261
 262   // Hold onto a weak reference to |filter| so that it can be used after passing
 263   // ownership to |event_filter|.
 264   base::DictionaryValue* filter_weak = filter.get();
 265   int id = g_event_filter.Get().AddEventMatcher(
 266       event_name, ParseEventMatcher(filter.Pass()));
 267   attached_matcher_ids_.insert(id);
 268
 269   // Only send IPCs the first time a filter gets added.
 270   std::string extension_id = context()->GetExtensionID();
 271   if (AddFilter(event_name, extension_id, *filter_weak)) {
 272     bool lazy = ExtensionFrameHelper::IsContextForEventPage(context());
 273     content::RenderThread::Get()->Send(new ExtensionHostMsg_AddFilteredListener(
 274         extension_id, event_name, *filter_weak, lazy));
 275   }
 276
 277   args.GetReturnValue().Set(static_cast<int32_t>(id));
 278 }
 279
 280 void EventBindings::DetachFilteredEventHandler(
 281     const v8::FunctionCallbackInfo<v8::Value>& args) {
 282   CHECK_EQ(2, args.Length());
 283   CHECK(args[0]->IsInt32());
 284   CHECK(args[1]->IsBoolean());
 285   DetachFilteredEvent(args[0]->Int32Value(), args[1]->BooleanValue());
 286 }
 287
 288 void EventBindings::DetachFilteredEvent(int matcher_id, bool is_manual) {
 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   std::string extension_id = context()->GetExtensionID();
 296   if (RemoveFilter(event_name, extension_id, event_matcher->value())) {
 297     bool remove_lazy =
 298         is_manual && ExtensionFrameHelper::IsContextForEventPage(context());
 299     content::RenderThread::Get()->Send(
 300         new ExtensionHostMsg_RemoveFilteredListener(
 301             extension_id, event_name, *event_matcher->value(), remove_lazy));
 302   }
 303
 304   event_filter.RemoveEventMatcher(matcher_id);
 305   attached_matcher_ids_.erase(matcher_id);
 306 }
 307
 308 void EventBindings::MatchAgainstEventFilter(
 309     const v8::FunctionCallbackInfo<v8::Value>& args) {
 310   v8::Isolate* isolate = args.GetIsolate();
 311   typedef std::set<EventFilter::MatcherID> MatcherIDs;
 312   EventFilter& event_filter = g_event_filter.Get();
 313   std::string event_name = *v8::String::Utf8Value(args[0]);
 314   EventFilteringInfo info =
 315       ParseFromObject(args[1]->ToObject(isolate), isolate);
 316   // Only match events routed to this context's RenderFrame or ones that don't
 317   // have a routingId in their filter.
 318   MatcherIDs matched_event_filters = event_filter.MatchEvent(
 319       event_name, info, context()->GetRenderFrame()->GetRoutingID());
 320   v8::Local<v8::Array> array(
 321       v8::Array::New(isolate, matched_event_filters.size()));
 322   int i = 0;
 323   for (MatcherIDs::iterator it = matched_event_filters.begin();
 324        it != matched_event_filters.end();
 325        ++it) {
 326     array->Set(v8::Integer::New(isolate, i++), v8::Integer::New(isolate, *it));
 327   }
 328   args.GetReturnValue().Set(array);
 329 }
 330
 331 scoped_ptr<EventMatcher> EventBindings::ParseEventMatcher(
 332     scoped_ptr<base::DictionaryValue> filter) {
 333   return make_scoped_ptr(new EventMatcher(
 334       filter.Pass(), context()->GetRenderFrame()->GetRoutingID()));
 335 }
 336
 337 void EventBindings::OnInvalidated() {
 338   // Detach all attached events that weren't attached. Iterate over a copy
 339   // because it will be mutated.
 340   std::set<std::string> attached_event_names_safe = attached_event_names_;
 341   for (const std::string& event_name : attached_event_names_safe) {
 342     DetachEvent(event_name, false /* is_manual */);
 343   }
 344   DCHECK(attached_event_names_.empty())
 345       << "Events cannot be attached during invalidation";
 346
 347   // Same for filtered events.
 348   std::set<int> attached_matcher_ids_safe = attached_matcher_ids_;
 349   for (int matcher_id : attached_matcher_ids_safe) {
 350     DetachFilteredEvent(matcher_id, false /* is_manual */);
 351   }
 352   DCHECK(attached_matcher_ids_.empty())
 353       << "Filtered events cannot be attached during invalidation";
 354 }
 355
 356 }  // namespace extensions