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      1 // Copyright (c) 2012 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 "chrome/renderer/extensions/event_bindings.h"
      6 
      7 #include <vector>
      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 "base/message_loop/message_loop.h"
     14 #include "chrome/common/extensions/background_info.h"
     15 #include "chrome/common/extensions/extension.h"
     16 #include "chrome/common/extensions/extension_messages.h"
     17 #include "chrome/common/extensions/extension_set.h"
     18 #include "chrome/common/extensions/value_counter.h"
     19 #include "chrome/common/url_constants.h"
     20 #include "chrome/renderer/extensions/chrome_v8_context.h"
     21 #include "chrome/renderer/extensions/chrome_v8_context_set.h"
     22 #include "chrome/renderer/extensions/chrome_v8_extension.h"
     23 #include "chrome/renderer/extensions/dispatcher.h"
     24 #include "chrome/renderer/extensions/event_bindings.h"
     25 #include "chrome/renderer/extensions/extension_helper.h"
     26 #include "chrome/renderer/extensions/user_script_slave.h"
     27 #include "content/public/renderer/render_thread.h"
     28 #include "content/public/renderer/render_view.h"
     29 #include "content/public/renderer/v8_value_converter.h"
     30 #include "extensions/common/event_filter.h"
     31 #include "extensions/common/view_type.h"
     32 #include "grit/renderer_resources.h"
     33 #include "third_party/WebKit/public/platform/WebURL.h"
     34 #include "third_party/WebKit/public/platform/WebURLRequest.h"
     35 #include "third_party/WebKit/public/web/WebDocument.h"
     36 #include "third_party/WebKit/public/web/WebFrame.h"
     37 #include "third_party/WebKit/public/web/WebView.h"
     38 #include "url/gurl.h"
     39 #include "v8/include/v8.h"
     40 
     41 using WebKit::WebFrame;
     42 using WebKit::WebURL;
     43 using content::RenderThread;
     44 
     45 namespace extensions {
     46 
     47 namespace {
     48 
     49 // A map of event names to the number of contexts listening to that event.
     50 // We notify the browser about event listeners when we transition between 0
     51 // and 1.
     52 typedef std::map<std::string, int> EventListenerCounts;
     53 
     54 // A map of extension IDs to listener counts for that extension.
     55 base::LazyInstance<std::map<std::string, EventListenerCounts> >
     56     g_listener_counts = LAZY_INSTANCE_INITIALIZER;
     57 
     58 // A map of event names to a (filter -> count) map. The map is used to keep
     59 // track of which filters are in effect for which events.
     60 // We notify the browser about filtered event listeners when we transition
     61 // between 0 and 1.
     62 typedef std::map<std::string, linked_ptr<ValueCounter> >
     63     FilteredEventListenerCounts;
     64 
     65 // A map of extension IDs to filtered listener counts for that extension.
     66 base::LazyInstance<std::map<std::string, FilteredEventListenerCounts> >
     67     g_filtered_listener_counts = LAZY_INSTANCE_INITIALIZER;
     68 
     69 base::LazyInstance<EventFilter> g_event_filter = LAZY_INSTANCE_INITIALIZER;
     70 
     71 // TODO(koz): Merge this into EventBindings.
     72 class ExtensionImpl : public ChromeV8Extension {
     73  public:
     74   explicit ExtensionImpl(Dispatcher* dispatcher, ChromeV8Context* context)
     75       : ChromeV8Extension(dispatcher, context) {
     76     RouteFunction("AttachEvent",
     77         base::Bind(&ExtensionImpl::AttachEvent, base::Unretained(this)));
     78     RouteFunction("DetachEvent",
     79         base::Bind(&ExtensionImpl::DetachEvent, base::Unretained(this)));
     80     RouteFunction("AttachFilteredEvent",
     81         base::Bind(&ExtensionImpl::AttachFilteredEvent,
     82                    base::Unretained(this)));
     83     RouteFunction("DetachFilteredEvent",
     84         base::Bind(&ExtensionImpl::DetachFilteredEvent,
     85                    base::Unretained(this)));
     86     RouteFunction("MatchAgainstEventFilter",
     87         base::Bind(&ExtensionImpl::MatchAgainstEventFilter,
     88                    base::Unretained(this)));
     89   }
     90 
     91   virtual ~ExtensionImpl() {}
     92 
     93   // Attach an event name to an object.
     94   void AttachEvent(const v8::FunctionCallbackInfo<v8::Value>& args) {
     95     CHECK_EQ(1, args.Length());
     96     CHECK(args[0]->IsString());
     97 
     98     std::string event_name = *v8::String::AsciiValue(args[0]->ToString());
     99 
    100     if (!dispatcher_->CheckContextAccessToExtensionAPI(event_name, context()))
    101       return;
    102 
    103     std::string extension_id = context()->GetExtensionID();
    104     EventListenerCounts& listener_counts =
    105         g_listener_counts.Get()[extension_id];
    106     if (++listener_counts[event_name] == 1) {
    107       content::RenderThread::Get()->Send(
    108           new ExtensionHostMsg_AddListener(extension_id, event_name));
    109     }
    110 
    111     // This is called the first time the page has added a listener. Since
    112     // the background page is the only lazy page, we know this is the first
    113     // time this listener has been registered.
    114     if (IsLazyBackgroundPage(GetRenderView(), context()->extension())) {
    115       content::RenderThread::Get()->Send(
    116           new ExtensionHostMsg_AddLazyListener(extension_id, event_name));
    117     }
    118   }
    119 
    120   void DetachEvent(const v8::FunctionCallbackInfo<v8::Value>& args) {
    121     CHECK_EQ(2, args.Length());
    122     CHECK(args[0]->IsString());
    123     CHECK(args[1]->IsBoolean());
    124 
    125     std::string event_name = *v8::String::AsciiValue(args[0]);
    126     bool is_manual = args[1]->BooleanValue();
    127 
    128     std::string extension_id = context()->GetExtensionID();
    129     EventListenerCounts& listener_counts =
    130         g_listener_counts.Get()[extension_id];
    131 
    132     if (--listener_counts[event_name] == 0) {
    133       content::RenderThread::Get()->Send(
    134           new ExtensionHostMsg_RemoveListener(extension_id, event_name));
    135     }
    136 
    137     // DetachEvent is called when the last listener for the context is
    138     // removed. If the context is the background page, and it removes the
    139     // last listener manually, then we assume that it is no longer interested
    140     // in being awakened for this event.
    141     if (is_manual && IsLazyBackgroundPage(GetRenderView(),
    142                                           context()->extension())) {
    143       content::RenderThread::Get()->Send(
    144           new ExtensionHostMsg_RemoveLazyListener(extension_id, event_name));
    145     }
    146   }
    147 
    148   // MatcherID AttachFilteredEvent(string event_name, object filter)
    149   // event_name - Name of the event to attach.
    150   // filter - Which instances of the named event are we interested in.
    151   // returns the id assigned to the listener, which will be returned from calls
    152   // to MatchAgainstEventFilter where this listener matches.
    153   void AttachFilteredEvent(const v8::FunctionCallbackInfo<v8::Value>& args) {
    154     CHECK_EQ(2, args.Length());
    155     CHECK(args[0]->IsString());
    156     CHECK(args[1]->IsObject());
    157 
    158     std::string event_name = *v8::String::AsciiValue(args[0]);
    159 
    160     // This method throws an exception if it returns false.
    161     if (!dispatcher_->CheckContextAccessToExtensionAPI(event_name, context()))
    162       return;
    163 
    164     std::string extension_id = context()->GetExtensionID();
    165     if (extension_id.empty()) {
    166       args.GetReturnValue().Set(static_cast<int32_t>(-1));
    167       return;
    168     }
    169 
    170     scoped_ptr<base::DictionaryValue> filter;
    171     scoped_ptr<content::V8ValueConverter> converter(
    172         content::V8ValueConverter::create());
    173 
    174     base::DictionaryValue* filter_dict = NULL;
    175     base::Value* filter_value =
    176         converter->FromV8Value(args[1]->ToObject(), context()->v8_context());
    177     if (!filter_value) {
    178       args.GetReturnValue().Set(static_cast<int32_t>(-1));
    179       return;
    180     }
    181     if (!filter_value->GetAsDictionary(&filter_dict)) {
    182       delete filter_value;
    183       args.GetReturnValue().Set(static_cast<int32_t>(-1));
    184       return;
    185     }
    186 
    187     filter.reset(filter_dict);
    188     EventFilter& event_filter = g_event_filter.Get();
    189     int id = event_filter.AddEventMatcher(event_name, ParseEventMatcher(
    190         filter.get()));
    191 
    192     // Only send IPCs the first time a filter gets added.
    193     if (AddFilter(event_name, extension_id, filter.get())) {
    194       bool lazy = IsLazyBackgroundPage(GetRenderView(), context()->extension());
    195       content::RenderThread::Get()->Send(
    196           new ExtensionHostMsg_AddFilteredListener(extension_id, event_name,
    197                                                    *filter, lazy));
    198     }
    199 
    200     args.GetReturnValue().Set(static_cast<int32_t>(id));
    201   }
    202 
    203   // Add a filter to |event_name| in |extension_id|, returning true if it
    204   // was the first filter for that event in that extension.
    205   static bool AddFilter(const std::string& event_name,
    206                         const std::string& extension_id,
    207                         base::DictionaryValue* filter) {
    208     FilteredEventListenerCounts& counts =
    209         g_filtered_listener_counts.Get()[extension_id];
    210     FilteredEventListenerCounts::iterator it = counts.find(event_name);
    211     if (it == counts.end())
    212       counts[event_name].reset(new ValueCounter);
    213 
    214     int result = counts[event_name]->Add(*filter);
    215     return 1 == result;
    216   }
    217 
    218   // Remove a filter from |event_name| in |extension_id|, returning true if it
    219   // was the last filter for that event in that extension.
    220   static bool RemoveFilter(const std::string& event_name,
    221                            const std::string& extension_id,
    222                            base::DictionaryValue* filter) {
    223     FilteredEventListenerCounts& counts =
    224         g_filtered_listener_counts.Get()[extension_id];
    225     FilteredEventListenerCounts::iterator it = counts.find(event_name);
    226     if (it == counts.end())
    227       return false;
    228     return 0 == it->second->Remove(*filter);
    229   }
    230 
    231   // void DetachFilteredEvent(int id, bool manual)
    232   // id     - Id of the event to detach.
    233   // manual - false if this is part of the extension unload process where all
    234   //          listeners are automatically detached.
    235   void DetachFilteredEvent(const v8::FunctionCallbackInfo<v8::Value>& args) {
    236     CHECK_EQ(2, args.Length());
    237     CHECK(args[0]->IsInt32());
    238     CHECK(args[1]->IsBoolean());
    239     bool is_manual = args[1]->BooleanValue();
    240 
    241     std::string extension_id = context()->GetExtensionID();
    242     if (extension_id.empty())
    243       return;
    244 
    245     int matcher_id = args[0]->Int32Value();
    246     EventFilter& event_filter = g_event_filter.Get();
    247     EventMatcher* event_matcher =
    248         event_filter.GetEventMatcher(matcher_id);
    249 
    250     const std::string& event_name = event_filter.GetEventName(matcher_id);
    251 
    252     // Only send IPCs the last time a filter gets removed.
    253     if (RemoveFilter(event_name, extension_id, event_matcher->value())) {
    254       bool lazy = is_manual && IsLazyBackgroundPage(GetRenderView(),
    255                                                     context()->extension());
    256       content::RenderThread::Get()->Send(
    257           new ExtensionHostMsg_RemoveFilteredListener(extension_id, event_name,
    258                                                       *event_matcher->value(),
    259                                                       lazy));
    260     }
    261 
    262     event_filter.RemoveEventMatcher(matcher_id);
    263   }
    264 
    265   void MatchAgainstEventFilter(
    266       const v8::FunctionCallbackInfo<v8::Value>& args) {
    267     typedef std::set<EventFilter::MatcherID> MatcherIDs;
    268     EventFilter& event_filter = g_event_filter.Get();
    269     std::string event_name = *v8::String::AsciiValue(args[0]->ToString());
    270     EventFilteringInfo info = ParseFromObject(args[1]->ToObject());
    271     // Only match events routed to this context's RenderView or ones that don't
    272     // have a routingId in their filter.
    273     MatcherIDs matched_event_filters = event_filter.MatchEvent(
    274         event_name, info, context()->GetRenderView()->GetRoutingID());
    275     v8::Handle<v8::Array> array(v8::Array::New(matched_event_filters.size()));
    276     int i = 0;
    277     for (MatcherIDs::iterator it = matched_event_filters.begin();
    278          it != matched_event_filters.end(); ++it) {
    279       array->Set(v8::Integer::New(i++), v8::Integer::New(*it));
    280     }
    281     args.GetReturnValue().Set(array);
    282   }
    283 
    284   static EventFilteringInfo ParseFromObject(v8::Handle<v8::Object> object) {
    285     EventFilteringInfo info;
    286     v8::Handle<v8::String> url(v8::String::New("url"));
    287     if (object->Has(url)) {
    288       v8::Handle<v8::Value> url_value(object->Get(url));
    289       info.SetURL(GURL(*v8::String::AsciiValue(url_value)));
    290     }
    291     v8::Handle<v8::String> instance_id(v8::String::New("instanceId"));
    292     if (object->Has(instance_id)) {
    293       v8::Handle<v8::Value> instance_id_value(object->Get(instance_id));
    294       info.SetInstanceID(instance_id_value->IntegerValue());
    295     }
    296     return info;
    297   }
    298 
    299  private:
    300   static bool IsLazyBackgroundPage(content::RenderView* render_view,
    301                                    const Extension* extension) {
    302     if (!render_view)
    303       return false;
    304     ExtensionHelper* helper = ExtensionHelper::Get(render_view);
    305     return (extension && BackgroundInfo::HasLazyBackgroundPage(extension) &&
    306             helper->view_type() == VIEW_TYPE_EXTENSION_BACKGROUND_PAGE);
    307   }
    308 
    309   scoped_ptr<EventMatcher> ParseEventMatcher(
    310       base::DictionaryValue* filter_dict) {
    311     return scoped_ptr<EventMatcher>(new EventMatcher(
    312         scoped_ptr<base::DictionaryValue>(filter_dict->DeepCopy()),
    313             context()->GetRenderView()->GetRoutingID()));
    314   }
    315 };
    316 
    317 }  // namespace
    318 
    319 // static
    320 ChromeV8Extension* EventBindings::Create(Dispatcher* dispatcher,
    321                                          ChromeV8Context* context) {
    322   return new ExtensionImpl(dispatcher, context);
    323 }
    324 
    325 }  // namespace extensions
    326