| // Copyright 2010 The Closure Library Authors. All Rights Reserved. |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS-IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| /** |
| * @fileoverview A global registry for entry points into a program, |
| * so that they can be instrumented. Each module should register their |
| * entry points with this registry. Designed to be compiled out |
| * if no instrumentation is requested. |
| * |
| * Entry points may be registered before or after a call to |
| * goog.debug.entryPointRegistry.monitorAll. If an entry point is registered |
| * later, the existing monitor will instrument the new entry point. |
| * |
| * @author nicksantos@google.com (Nick Santos) |
| */ |
| |
| goog.provide('goog.debug.EntryPointMonitor'); |
| goog.provide('goog.debug.entryPointRegistry'); |
| |
| goog.require('goog.asserts'); |
| |
| |
| |
| /** |
| * @interface |
| */ |
| goog.debug.EntryPointMonitor = function() {}; |
| |
| |
| /** |
| * Instruments a function. |
| * |
| * @param {!Function} fn A function to instrument. |
| * @return {!Function} The instrumented function. |
| */ |
| goog.debug.EntryPointMonitor.prototype.wrap; |
| |
| |
| /** |
| * Try to remove an instrumentation wrapper created by this monitor. |
| * If the function passed to unwrap is not a wrapper created by this |
| * monitor, then we will do nothing. |
| * |
| * Notice that some wrappers may not be unwrappable. For example, if other |
| * monitors have applied their own wrappers, then it will be impossible to |
| * unwrap them because their wrappers will have captured our wrapper. |
| * |
| * So it is important that entry points are unwrapped in the reverse |
| * order that they were wrapped. |
| * |
| * @param {!Function} fn A function to unwrap. |
| * @return {!Function} The unwrapped function, or {@code fn} if it was not |
| * a wrapped function created by this monitor. |
| */ |
| goog.debug.EntryPointMonitor.prototype.unwrap; |
| |
| |
| /** |
| * An array of entry point callbacks. |
| * @type {!Array<function(!Function)>} |
| * @private |
| */ |
| goog.debug.entryPointRegistry.refList_ = []; |
| |
| |
| /** |
| * Monitors that should wrap all the entry points. |
| * @type {!Array<!goog.debug.EntryPointMonitor>} |
| * @private |
| */ |
| goog.debug.entryPointRegistry.monitors_ = []; |
| |
| |
| /** |
| * Whether goog.debug.entryPointRegistry.monitorAll has ever been called. |
| * Checking this allows the compiler to optimize out the registrations. |
| * @type {boolean} |
| * @private |
| */ |
| goog.debug.entryPointRegistry.monitorsMayExist_ = false; |
| |
| |
| /** |
| * Register an entry point with this module. |
| * |
| * The entry point will be instrumented when a monitor is passed to |
| * goog.debug.entryPointRegistry.monitorAll. If this has already occurred, the |
| * entry point is instrumented immediately. |
| * |
| * @param {function(!Function)} callback A callback function which is called |
| * with a transforming function to instrument the entry point. The callback |
| * is responsible for wrapping the relevant entry point with the |
| * transforming function. |
| */ |
| goog.debug.entryPointRegistry.register = function(callback) { |
| // Don't use push(), so that this can be compiled out. |
| goog.debug.entryPointRegistry.refList_[ |
| goog.debug.entryPointRegistry.refList_.length] = callback; |
| // If no one calls monitorAll, this can be compiled out. |
| if (goog.debug.entryPointRegistry.monitorsMayExist_) { |
| var monitors = goog.debug.entryPointRegistry.monitors_; |
| for (var i = 0; i < monitors.length; i++) { |
| callback(goog.bind(monitors[i].wrap, monitors[i])); |
| } |
| } |
| }; |
| |
| |
| /** |
| * Configures a monitor to wrap all entry points. |
| * |
| * Entry points that have already been registered are immediately wrapped by |
| * the monitor. When an entry point is registered in the future, it will also |
| * be wrapped by the monitor when it is registered. |
| * |
| * @param {!goog.debug.EntryPointMonitor} monitor An entry point monitor. |
| */ |
| goog.debug.entryPointRegistry.monitorAll = function(monitor) { |
| goog.debug.entryPointRegistry.monitorsMayExist_ = true; |
| var transformer = goog.bind(monitor.wrap, monitor); |
| for (var i = 0; i < goog.debug.entryPointRegistry.refList_.length; i++) { |
| goog.debug.entryPointRegistry.refList_[i](transformer); |
| } |
| goog.debug.entryPointRegistry.monitors_.push(monitor); |
| }; |
| |
| |
| /** |
| * Try to unmonitor all the entry points that have already been registered. If |
| * an entry point is registered in the future, it will not be wrapped by the |
| * monitor when it is registered. Note that this may fail if the entry points |
| * have additional wrapping. |
| * |
| * @param {!goog.debug.EntryPointMonitor} monitor The last monitor to wrap |
| * the entry points. |
| * @throws {Error} If the monitor is not the most recently configured monitor. |
| */ |
| goog.debug.entryPointRegistry.unmonitorAllIfPossible = function(monitor) { |
| var monitors = goog.debug.entryPointRegistry.monitors_; |
| goog.asserts.assert(monitor == monitors[monitors.length - 1], |
| 'Only the most recent monitor can be unwrapped.'); |
| var transformer = goog.bind(monitor.unwrap, monitor); |
| for (var i = 0; i < goog.debug.entryPointRegistry.refList_.length; i++) { |
| goog.debug.entryPointRegistry.refList_[i](transformer); |
| } |
| monitors.length--; |
| }; |