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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 
IsLazyBackgroundPage(content::RenderView * render_view,const Extension * extension)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 
ParseFromObject(v8::Handle<v8::Object> object,v8::Isolate * isolate)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.
AddFilter(const std::string & event_name,const std::string & extension_id,base::DictionaryValue * filter)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.
RemoveFilter(const std::string & event_name,const std::string & extension_id,base::DictionaryValue * filter)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 
EventBindings(Dispatcher * dispatcher,ScriptContext * context)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 
~EventBindings()137 EventBindings::~EventBindings() {}
138 
139 // Attach an event name to an object.
AttachEvent(const v8::FunctionCallbackInfo<v8::Value> & args)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 
DetachEvent(const v8::FunctionCallbackInfo<v8::Value> & args)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.
AttachFilteredEvent(const v8::FunctionCallbackInfo<v8::Value> & args)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 
DetachFilteredEvent(const v8::FunctionCallbackInfo<v8::Value> & args)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 
MatchAgainstEventFilter(const v8::FunctionCallbackInfo<v8::Value> & args)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 
ParseEventMatcher(base::DictionaryValue * filter_dict)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
304