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1 // Copyright (c) 2011 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 var chrome = chrome || {}; | |
6 (function () { | |
7 native function GetChromeHidden(); | |
8 native function AttachEvent(eventName); | |
9 native function DetachEvent(eventName); | |
10 native function GetExternalFileEntry(fileDefinition); | |
11 native function Print(); | |
12 | |
13 var chromeHidden = GetChromeHidden(); | |
14 | |
15 // Local implementation of JSON.parse & JSON.stringify that protect us | |
16 // from being clobbered by an extension. | |
17 chromeHidden.JSON = new (function() { | |
18 var $Object = Object; | |
19 var $Array = Array; | |
20 var $jsonStringify = JSON.stringify; | |
21 var $jsonParse = JSON.parse; | |
22 | |
23 this.stringify = function(thing) { | |
24 var customizedObjectToJSON = $Object.prototype.toJSON; | |
25 var customizedArrayToJSON = $Array.prototype.toJSON; | |
26 if (customizedObjectToJSON !== undefined) { | |
27 $Object.prototype.toJSON = null; | |
28 } | |
29 if (customizedArrayToJSON !== undefined) { | |
30 $Array.prototype.toJSON = null; | |
31 } | |
32 try { | |
33 return $jsonStringify(thing); | |
34 } finally { | |
35 if (customizedObjectToJSON !== undefined) { | |
36 $Object.prototype.toJSON = customizedObjectToJSON; | |
37 } | |
38 if (customizedArrayToJSON !== undefined) { | |
39 $Array.prototype.toJSON = customizedArrayToJSON; | |
40 } | |
41 } | |
42 }; | |
43 | |
44 this.parse = function(thing) { | |
45 return $jsonParse(thing); | |
46 }; | |
47 })(); | |
48 | |
49 // Event object. If opt_eventName is provided, this object represents | |
50 // the unique instance of that named event, and dispatching an event | |
51 // with that name will route through this object's listeners. | |
52 // | |
53 // Example: | |
54 // chrome.tabs.onChanged = new chrome.Event("tab-changed"); | |
55 // chrome.tabs.onChanged.addListener(function(data) { alert(data); }); | |
56 // chromeHidden.Event.dispatch("tab-changed", "hi"); | |
57 // will result in an alert dialog that says 'hi'. | |
58 chrome.Event = function(opt_eventName, opt_argSchemas) { | |
59 this.eventName_ = opt_eventName; | |
60 this.listeners_ = []; | |
61 | |
62 // Validate event parameters if we are in debug. | |
63 if (opt_argSchemas && | |
64 chromeHidden.validateCallbacks && | |
65 chromeHidden.validate) { | |
66 | |
67 this.validate_ = function(args) { | |
68 try { | |
69 chromeHidden.validate(args, opt_argSchemas); | |
70 } catch (exception) { | |
71 return "Event validation error during " + opt_eventName + " -- " + | |
72 exception; | |
73 } | |
74 }; | |
75 } | |
76 }; | |
77 | |
78 // A map of event names to the event object that is registered to that name. | |
79 var attachedNamedEvents = {}; | |
80 | |
81 // An array of all attached event objects, used for detaching on unload. | |
82 var allAttachedEvents = []; | |
83 | |
84 chromeHidden.Event = {}; | |
85 | |
86 // Dispatches a named event with the given JSON array, which is deserialized | |
87 // before dispatch. The JSON array is the list of arguments that will be | |
88 // sent with the event callback. | |
89 chromeHidden.Event.dispatchJSON = function(name, args) { | |
90 if (attachedNamedEvents[name]) { | |
91 if (args) { | |
92 args = chromeHidden.JSON.parse(args); | |
93 // TODO(zelidrag|aa): Remove this hack from here once we enable event | |
94 // JSON payload unpacking on C++ side. | |
95 if (name == "fileBrowserHandler.onExecute") { | |
96 if (args.length < 2) | |
97 return; | |
98 var fileList = args[1].entries; | |
99 if (!fileList) | |
100 return; | |
101 // The second parameter for this event's payload is file definition | |
102 // dictionary that we used to reconstruct File API's Entry instance | |
103 // here. | |
104 for (var i = 0; i < fileList.length; i++) | |
105 fileList[i] = GetExternalFileEntry(fileList[i]); | |
106 } | |
107 } | |
108 return attachedNamedEvents[name].dispatch.apply( | |
109 attachedNamedEvents[name], args); | |
110 } | |
111 }; | |
112 | |
113 // Dispatches a named event with the given arguments, supplied as an array. | |
114 chromeHidden.Event.dispatch = function(name, args) { | |
115 if (attachedNamedEvents[name]) { | |
116 attachedNamedEvents[name].dispatch.apply( | |
117 attachedNamedEvents[name], args); | |
118 } | |
119 }; | |
120 | |
121 // Test if a named event has any listeners. | |
122 chromeHidden.Event.hasListener = function(name) { | |
123 return (attachedNamedEvents[name] && | |
124 attachedNamedEvents[name].listeners_.length > 0); | |
125 }; | |
126 | |
127 // Registers a callback to be called when this event is dispatched. | |
128 chrome.Event.prototype.addListener = function(cb) { | |
129 if (this.listeners_.length == 0) { | |
130 this.attach_(); | |
131 } | |
132 this.listeners_.push(cb); | |
133 }; | |
134 | |
135 // Unregisters a callback. | |
136 chrome.Event.prototype.removeListener = function(cb) { | |
137 var idx = this.findListener_(cb); | |
138 if (idx == -1) { | |
139 return; | |
140 } | |
141 | |
142 this.listeners_.splice(idx, 1); | |
143 if (this.listeners_.length == 0) { | |
144 this.detach_(); | |
145 } | |
146 }; | |
147 | |
148 // Test if the given callback is registered for this event. | |
149 chrome.Event.prototype.hasListener = function(cb) { | |
150 return this.findListener_(cb) > -1; | |
151 }; | |
152 | |
153 // Test if any callbacks are registered for this event. | |
154 chrome.Event.prototype.hasListeners = function(cb) { | |
155 return this.listeners_.length > 0; | |
156 }; | |
157 | |
158 // Returns the index of the given callback if registered, or -1 if not | |
159 // found. | |
160 chrome.Event.prototype.findListener_ = function(cb) { | |
161 for (var i = 0; i < this.listeners_.length; i++) { | |
162 if (this.listeners_[i] == cb) { | |
163 return i; | |
164 } | |
165 } | |
166 | |
167 return -1; | |
168 }; | |
169 | |
170 // Dispatches this event object to all listeners, passing all supplied | |
171 // arguments to this function each listener. | |
172 chrome.Event.prototype.dispatch = function(varargs) { | |
173 var args = Array.prototype.slice.call(arguments); | |
174 if (this.validate_) { | |
175 var validationErrors = this.validate_(args); | |
176 if (validationErrors) { | |
177 return validationErrors; | |
178 } | |
179 } | |
180 for (var i = 0; i < this.listeners_.length; i++) { | |
181 try { | |
182 this.listeners_[i].apply(null, args); | |
183 } catch (e) { | |
184 console.error("Error in event handler for '" + this.eventName_ + | |
185 "': " + e.stack); | |
186 } | |
187 } | |
188 }; | |
189 | |
190 // Attaches this event object to its name. Only one object can have a given | |
191 // name. | |
192 chrome.Event.prototype.attach_ = function() { | |
193 AttachEvent(this.eventName_); | |
194 allAttachedEvents[allAttachedEvents.length] = this; | |
195 if (!this.eventName_) | |
196 return; | |
197 | |
198 if (attachedNamedEvents[this.eventName_]) { | |
199 throw new Error("chrome.Event '" + this.eventName_ + | |
200 "' is already attached."); | |
201 } | |
202 | |
203 attachedNamedEvents[this.eventName_] = this; | |
204 }; | |
205 | |
206 // Detaches this event object from its name. | |
207 chrome.Event.prototype.detach_ = function() { | |
208 var i = allAttachedEvents.indexOf(this); | |
209 if (i >= 0) | |
210 delete allAttachedEvents[i]; | |
211 DetachEvent(this.eventName_); | |
212 if (!this.eventName_) | |
213 return; | |
214 | |
215 if (!attachedNamedEvents[this.eventName_]) { | |
216 throw new Error("chrome.Event '" + this.eventName_ + | |
217 "' is not attached."); | |
218 } | |
219 | |
220 delete attachedNamedEvents[this.eventName_]; | |
221 }; | |
222 | |
223 chrome.Event.prototype.destroy_ = function() { | |
224 this.listeners_ = []; | |
225 this.validate_ = []; | |
226 this.detach_(); | |
227 }; | |
228 | |
229 // Special load events: we don't use the DOM unload because that slows | |
230 // down tab shutdown. On the other hand, onUnload might not always fire, | |
231 // since Chrome will terminate renderers on shutdown (SuddenTermination). | |
232 chromeHidden.onLoad = new chrome.Event(); | |
233 chromeHidden.onUnload = new chrome.Event(); | |
234 | |
235 chromeHidden.dispatchOnLoad = function(extensionId, isExtensionProcess, | |
236 isIncognitoContext) { | |
237 chromeHidden.onLoad.dispatch(extensionId, isExtensionProcess, | |
238 isIncognitoContext); | |
239 }; | |
240 | |
241 chromeHidden.dispatchOnUnload = function() { | |
242 chromeHidden.onUnload.dispatch(); | |
243 for (var i = 0; i < allAttachedEvents.length; ++i) { | |
244 var event = allAttachedEvents[i]; | |
245 if (event) | |
246 event.detach_(); | |
247 } | |
248 }; | |
249 | |
250 chromeHidden.dispatchError = function(msg) { | |
251 console.error(msg); | |
252 }; | |
253 })(); | |
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