gecko-dev/testing/modules/MockRegistrar.jsm

137 lines
3.6 KiB
JavaScript

/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
"use strict";
var EXPORTED_SYMBOLS = ["MockRegistrar"];
const Cm = Components.manager;
const { Log } = ChromeUtils.import("resource://gre/modules/Log.jsm");
const { XPCOMUtils } = ChromeUtils.import(
"resource://gre/modules/XPCOMUtils.jsm"
);
var logger = Log.repository.getLogger("MockRegistrar");
XPCOMUtils.defineLazyServiceGetter(
this,
"UUIDGen",
"@mozilla.org/uuid-generator;1",
"nsIUUIDGenerator"
);
var MockRegistrar = Object.freeze({
_registeredComponents: new Map(),
_originalCIDs: new Map(),
get registrar() {
return Cm.QueryInterface(Ci.nsIComponentRegistrar);
},
/**
* Register a mock to override target interfaces.
* The target interface may be accessed through _genuine property of the mock.
* If you register multiple mocks to the same contract ID, you have to call
* unregister in reverse order. Otherwise the previous factory will not be
* restored.
*
* @param contractID The contract ID of the interface which is overridden by
the mock.
* e.g. "@mozilla.org/file/directory_service;1"
* @param mock An object which implements interfaces for the contract ID.
* @param args An array which is passed in the constructor of mock.
*
* @return The CID of the mock.
*/
register(contractID, mock, args) {
let originalCID = this._originalCIDs.get(contractID);
if (!originalCID) {
originalCID = this.registrar.contractIDToCID(contractID);
this._originalCIDs.set(contractID, originalCID);
}
let originalFactory = Cm.getClassObject(originalCID, Ci.nsIFactory);
let cid = UUIDGen.generateUUID();
let factory = {
createInstance(outer, iid) {
if (outer) {
throw Components.Exception("", Cr.NS_ERROR_NO_AGGREGATION);
}
let wrappedMock;
if (mock.prototype && mock.prototype.constructor) {
wrappedMock = Object.create(mock.prototype);
mock.apply(wrappedMock, args);
} else {
wrappedMock = mock;
}
try {
let genuine = originalFactory.createInstance(outer, iid);
wrappedMock._genuine = genuine;
} catch (ex) {
logger.info("Creating original instance failed", ex);
}
return wrappedMock.QueryInterface(iid);
},
lockFactory(lock) {
throw Components.Exception("", Cr.NS_ERROR_NOT_IMPLEMENTED);
},
QueryInterface: ChromeUtils.generateQI(["nsIFactory"]),
};
this.registrar.registerFactory(
cid,
"A Mock for " + contractID,
contractID,
factory
);
this._registeredComponents.set(cid, {
contractID,
factory,
originalCID,
});
return cid;
},
/**
* Unregister the mock.
*
* @param cid The CID of the mock.
*/
unregister(cid) {
let component = this._registeredComponents.get(cid);
if (!component) {
return;
}
this.registrar.unregisterFactory(cid, component.factory);
if (component.originalCID) {
// Passing `null` for the factory re-maps the contract ID to the
// entry for its original CID.
this.registrar.registerFactory(
component.originalCID,
"",
component.contractID,
null
);
}
this._registeredComponents.delete(cid);
},
/**
* Unregister all registered mocks.
*/
unregisterAll() {
for (let cid of this._registeredComponents.keys()) {
this.unregister(cid);
}
},
});