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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 
     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 
     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.
     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.
    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 
    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 
    137 EventBindings::~EventBindings() {}
    138 
    139 // Attach an event name to an object.
    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(
    154         new ExtensionHostMsg_AddListener(extension_id, 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 
    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(
    181         new ExtensionHostMsg_RemoveListener(extension_id, 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.
    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   if (extension_id.empty()) {
    214     args.GetReturnValue().Set(static_cast<int32_t>(-1));
    215     return;
    216   }
    217 
    218   scoped_ptr<base::DictionaryValue> filter;
    219   scoped_ptr<content::V8ValueConverter> converter(
    220       content::V8ValueConverter::create());
    221 
    222   base::DictionaryValue* filter_dict = NULL;
    223   base::Value* filter_value =
    224       converter->FromV8Value(args[1]->ToObject(), context()->v8_context());
    225   if (!filter_value) {
    226     args.GetReturnValue().Set(static_cast<int32_t>(-1));
    227     return;
    228   }
    229   if (!filter_value->GetAsDictionary(&filter_dict)) {
    230     delete filter_value;
    231     args.GetReturnValue().Set(static_cast<int32_t>(-1));
    232     return;
    233   }
    234 
    235   filter.reset(filter_dict);
    236   EventFilter& event_filter = g_event_filter.Get();
    237   int id =
    238       event_filter.AddEventMatcher(event_name, ParseEventMatcher(filter.get()));
    239 
    240   // Only send IPCs the first time a filter gets added.
    241   if (AddFilter(event_name, extension_id, filter.get())) {
    242     bool lazy = IsLazyBackgroundPage(context()->GetRenderView(),
    243                                      context()->extension());
    244     content::RenderThread::Get()->Send(new ExtensionHostMsg_AddFilteredListener(
    245         extension_id, event_name, *filter, lazy));
    246   }
    247 
    248   args.GetReturnValue().Set(static_cast<int32_t>(id));
    249 }
    250 
    251 void EventBindings::DetachFilteredEvent(
    252     const v8::FunctionCallbackInfo<v8::Value>& args) {
    253   CHECK_EQ(2, args.Length());
    254   CHECK(args[0]->IsInt32());
    255   CHECK(args[1]->IsBoolean());
    256   bool is_manual = args[1]->BooleanValue();
    257 
    258   std::string extension_id = context()->GetExtensionID();
    259   if (extension_id.empty())
    260     return;
    261 
    262   int matcher_id = args[0]->Int32Value();
    263   EventFilter& event_filter = g_event_filter.Get();
    264   EventMatcher* event_matcher = event_filter.GetEventMatcher(matcher_id);
    265 
    266   const std::string& event_name = event_filter.GetEventName(matcher_id);
    267 
    268   // Only send IPCs the last time a filter gets removed.
    269   if (RemoveFilter(event_name, extension_id, event_matcher->value())) {
    270     bool lazy = is_manual && IsLazyBackgroundPage(context()->GetRenderView(),
    271                                                   context()->extension());
    272     content::RenderThread::Get()->Send(
    273         new ExtensionHostMsg_RemoveFilteredListener(
    274             extension_id, event_name, *event_matcher->value(), lazy));
    275   }
    276 
    277   event_filter.RemoveEventMatcher(matcher_id);
    278 }
    279 
    280 void EventBindings::MatchAgainstEventFilter(
    281     const v8::FunctionCallbackInfo<v8::Value>& args) {
    282   v8::Isolate* isolate = args.GetIsolate();
    283   typedef std::set<EventFilter::MatcherID> MatcherIDs;
    284   EventFilter& event_filter = g_event_filter.Get();
    285   std::string event_name = *v8::String::Utf8Value(args[0]->ToString());
    286   EventFilteringInfo info = ParseFromObject(args[1]->ToObject(), isolate);
    287   // Only match events routed to this context's RenderView or ones that don't
    288   // have a routingId in their filter.
    289   MatcherIDs matched_event_filters = event_filter.MatchEvent(
    290       event_name, info, context()->GetRenderView()->GetRoutingID());
    291   v8::Handle<v8::Array> array(
    292       v8::Array::New(isolate, matched_event_filters.size()));
    293   int i = 0;
    294   for (MatcherIDs::iterator it = matched_event_filters.begin();
    295        it != matched_event_filters.end();
    296        ++it) {
    297     array->Set(v8::Integer::New(isolate, i++), v8::Integer::New(isolate, *it));
    298   }
    299   args.GetReturnValue().Set(array);
    300 }
    301 
    302 scoped_ptr<EventMatcher> EventBindings::ParseEventMatcher(
    303     base::DictionaryValue* filter_dict) {
    304   return scoped_ptr<EventMatcher>(new EventMatcher(
    305       scoped_ptr<base::DictionaryValue>(filter_dict->DeepCopy()),
    306       context()->GetRenderView()->GetRoutingID()));
    307 }
    308 
    309 }  // namespace extensions
    310