mirror of
https://github.com/classilla/tenfourfox.git
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91 lines
3.0 KiB
JavaScript
91 lines
3.0 KiB
JavaScript
/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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/**
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* Allows registering a mock XPCOM component, that temporarily replaces the
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* original one when an object implementing a given ContractID is requested
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* using createInstance.
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*
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* @param aContractID
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* The ContractID of the component to replace, for example
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* "@mozilla.org/filepicker;1".
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*
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* @param aReplacementCtor
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* The constructor function for the JavaScript object that will be
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* created every time createInstance is called. This object must
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* implement QueryInterface and provide the XPCOM interfaces required by
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* the specified ContractID (for example
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* Components.interfaces.nsIFilePicker).
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*/
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function MockObjectRegisterer(aContractID, aReplacementCtor) {
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this._contractID = aContractID;
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this._replacementCtor = aReplacementCtor;
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}
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MockObjectRegisterer.prototype = {
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/**
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* Replaces the current factory with one that returns a new mock object.
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*
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* After register() has been called, it is mandatory to call unregister() to
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* restore the original component. Usually, you should use a try-catch block
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* to ensure that unregister() is called.
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*/
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register: function MOR_register() {
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if (this._originalFactory)
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throw new Exception("Invalid object state when calling register()");
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// Define a factory that creates a new object using the given constructor.
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var providedConstructor = this._replacementCtor;
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this._mockFactory = {
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createInstance: function MF_createInstance(aOuter, aIid) {
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if (aOuter != null)
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throw SpecialPowers.Cr.NS_ERROR_NO_AGGREGATION;
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return new providedConstructor().QueryInterface(aIid);
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}
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};
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var retVal = SpecialPowers.swapFactoryRegistration(this._cid, this._contractID, this._mockFactory, this._originalFactory);
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if ('error' in retVal) {
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throw new Exception("ERROR: " + retVal.error);
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} else {
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this._cid = retVal.cid;
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this._originalFactory = retVal.originalFactory;
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}
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},
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/**
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* Restores the original factory.
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*/
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unregister: function MOR_unregister() {
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if (!this._originalFactory)
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throw new Exception("Invalid object state when calling unregister()");
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// Free references to the mock factory.
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SpecialPowers.swapFactoryRegistration(this._cid, this._contractID, this._mockFactory, this._originalFactory);
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// Allow registering a mock factory again later.
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this._cid = null;
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this._originalFactory = null;
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this._mockFactory = null;
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},
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// --- Private methods and properties ---
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/**
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* The factory of the component being replaced.
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*/
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_originalFactory: null,
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/**
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* The CID under which the mock contractID was registered.
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*/
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_cid: null,
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/**
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* The nsIFactory that was automatically generated by this object.
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*/
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_mockFactory: null
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}
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