1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/testing/mochitest/tests/SimpleTest/MockObjects.js Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,90 @@
1.4 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.5 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.6 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.7 +
1.8 +/**
1.9 + * Allows registering a mock XPCOM component, that temporarily replaces the
1.10 + * original one when an object implementing a given ContractID is requested
1.11 + * using createInstance.
1.12 + *
1.13 + * @param aContractID
1.14 + * The ContractID of the component to replace, for example
1.15 + * "@mozilla.org/filepicker;1".
1.16 + *
1.17 + * @param aReplacementCtor
1.18 + * The constructor function for the JavaScript object that will be
1.19 + * created every time createInstance is called. This object must
1.20 + * implement QueryInterface and provide the XPCOM interfaces required by
1.21 + * the specified ContractID (for example
1.22 + * Components.interfaces.nsIFilePicker).
1.23 + */
1.24 +
1.25 +function MockObjectRegisterer(aContractID, aReplacementCtor) {
1.26 + this._contractID = aContractID;
1.27 + this._replacementCtor = aReplacementCtor;
1.28 +}
1.29 +
1.30 +MockObjectRegisterer.prototype = {
1.31 + /**
1.32 + * Replaces the current factory with one that returns a new mock object.
1.33 + *
1.34 + * After register() has been called, it is mandatory to call unregister() to
1.35 + * restore the original component. Usually, you should use a try-catch block
1.36 + * to ensure that unregister() is called.
1.37 + */
1.38 + register: function MOR_register() {
1.39 + if (this._originalFactory)
1.40 + throw new Exception("Invalid object state when calling register()");
1.41 +
1.42 + // Define a factory that creates a new object using the given constructor.
1.43 + var providedConstructor = this._replacementCtor;
1.44 + this._mockFactory = {
1.45 + createInstance: function MF_createInstance(aOuter, aIid) {
1.46 + if (aOuter != null)
1.47 + throw SpecialPowers.Cr.NS_ERROR_NO_AGGREGATION;
1.48 + return new providedConstructor().QueryInterface(aIid);
1.49 + }
1.50 + };
1.51 +
1.52 + var retVal = SpecialPowers.swapFactoryRegistration(this._cid, this._contractID, this._mockFactory, this._originalFactory);
1.53 + if ('error' in retVal) {
1.54 + throw new Exception("ERROR: " + retVal.error);
1.55 + } else {
1.56 + this._cid = retVal.cid;
1.57 + this._originalFactory = retVal.originalFactory;
1.58 + }
1.59 + },
1.60 +
1.61 + /**
1.62 + * Restores the original factory.
1.63 + */
1.64 + unregister: function MOR_unregister() {
1.65 + if (!this._originalFactory)
1.66 + throw new Exception("Invalid object state when calling unregister()");
1.67 +
1.68 + // Free references to the mock factory.
1.69 + SpecialPowers.swapFactoryRegistration(this._cid, this._contractID, this._mockFactory, this._originalFactory);
1.70 +
1.71 + // Allow registering a mock factory again later.
1.72 + this._cid = null;
1.73 + this._originalFactory = null;
1.74 + this._mockFactory = null;
1.75 + },
1.76 +
1.77 + // --- Private methods and properties ---
1.78 +
1.79 + /**
1.80 + * The factory of the component being replaced.
1.81 + */
1.82 + _originalFactory: null,
1.83 +
1.84 + /**
1.85 + * The CID under which the mock contractID was registered.
1.86 + */
1.87 + _cid: null,
1.88 +
1.89 + /**
1.90 + * The nsIFactory that was automatically generated by this object.
1.91 + */
1.92 + _mockFactory: null
1.93 +}
