| // Copyright 2008 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 Utilities to check the preconditions, postconditions and |
| * invariants runtime. |
| * |
| * Methods in this package should be given special treatment by the compiler |
| * for type-inference. For example, <code>goog.asserts.assert(foo)</code> |
| * will restrict <code>foo</code> to a truthy value. |
| * |
| * The compiler has an option to disable asserts. So code like: |
| * <code> |
| * var x = goog.asserts.assert(foo()); goog.asserts.assert(bar()); |
| * </code> |
| * will be transformed into: |
| * <code> |
| * var x = foo(); |
| * </code> |
| * The compiler will leave in foo() (because its return value is used), |
| * but it will remove bar() because it assumes it does not have side-effects. |
| * |
| * @author agrieve@google.com (Andrew Grieve) |
| */ |
| |
| goog.provide('goog.asserts'); |
| goog.provide('goog.asserts.AssertionError'); |
| |
| goog.require('goog.debug.Error'); |
| goog.require('goog.dom.NodeType'); |
| goog.require('goog.string'); |
| |
| |
| /** |
| * @define {boolean} Whether to strip out asserts or to leave them in. |
| */ |
| goog.define('goog.asserts.ENABLE_ASSERTS', goog.DEBUG); |
| |
| |
| |
| /** |
| * Error object for failed assertions. |
| * @param {string} messagePattern The pattern that was used to form message. |
| * @param {!Array<*>} messageArgs The items to substitute into the pattern. |
| * @constructor |
| * @extends {goog.debug.Error} |
| * @final |
| */ |
| goog.asserts.AssertionError = function(messagePattern, messageArgs) { |
| messageArgs.unshift(messagePattern); |
| goog.debug.Error.call(this, goog.string.subs.apply(null, messageArgs)); |
| // Remove the messagePattern afterwards to avoid permenantly modifying the |
| // passed in array. |
| messageArgs.shift(); |
| |
| /** |
| * The message pattern used to format the error message. Error handlers can |
| * use this to uniquely identify the assertion. |
| * @type {string} |
| */ |
| this.messagePattern = messagePattern; |
| }; |
| goog.inherits(goog.asserts.AssertionError, goog.debug.Error); |
| |
| |
| /** @override */ |
| goog.asserts.AssertionError.prototype.name = 'AssertionError'; |
| |
| |
| /** |
| * The default error handler. |
| * @param {!goog.asserts.AssertionError} e The exception to be handled. |
| */ |
| goog.asserts.DEFAULT_ERROR_HANDLER = function(e) { throw e; }; |
| |
| |
| /** |
| * The handler responsible for throwing or logging assertion errors. |
| * @private {function(!goog.asserts.AssertionError)} |
| */ |
| goog.asserts.errorHandler_ = goog.asserts.DEFAULT_ERROR_HANDLER; |
| |
| |
| /** |
| * Throws an exception with the given message and "Assertion failed" prefixed |
| * onto it. |
| * @param {string} defaultMessage The message to use if givenMessage is empty. |
| * @param {Array<*>} defaultArgs The substitution arguments for defaultMessage. |
| * @param {string|undefined} givenMessage Message supplied by the caller. |
| * @param {Array<*>} givenArgs The substitution arguments for givenMessage. |
| * @throws {goog.asserts.AssertionError} When the value is not a number. |
| * @private |
| */ |
| goog.asserts.doAssertFailure_ = |
| function(defaultMessage, defaultArgs, givenMessage, givenArgs) { |
| var message = 'Assertion failed'; |
| if (givenMessage) { |
| message += ': ' + givenMessage; |
| var args = givenArgs; |
| } else if (defaultMessage) { |
| message += ': ' + defaultMessage; |
| args = defaultArgs; |
| } |
| // The '' + works around an Opera 10 bug in the unit tests. Without it, |
| // a stack trace is added to var message above. With this, a stack trace is |
| // not added until this line (it causes the extra garbage to be added after |
| // the assertion message instead of in the middle of it). |
| var e = new goog.asserts.AssertionError('' + message, args || []); |
| goog.asserts.errorHandler_(e); |
| }; |
| |
| |
| /** |
| * Sets a custom error handler that can be used to customize the behavior of |
| * assertion failures, for example by turning all assertion failures into log |
| * messages. |
| * @param {function(!goog.asserts.AssertionError)} errorHandler |
| */ |
| goog.asserts.setErrorHandler = function(errorHandler) { |
| if (goog.asserts.ENABLE_ASSERTS) { |
| goog.asserts.errorHandler_ = errorHandler; |
| } |
| }; |
| |
| |
| /** |
| * Checks if the condition evaluates to true if goog.asserts.ENABLE_ASSERTS is |
| * true. |
| * @template T |
| * @param {T} condition The condition to check. |
| * @param {string=} opt_message Error message in case of failure. |
| * @param {...*} var_args The items to substitute into the failure message. |
| * @return {T} The value of the condition. |
| * @throws {goog.asserts.AssertionError} When the condition evaluates to false. |
| */ |
| goog.asserts.assert = function(condition, opt_message, var_args) { |
| if (goog.asserts.ENABLE_ASSERTS && !condition) { |
| goog.asserts.doAssertFailure_('', null, opt_message, |
| Array.prototype.slice.call(arguments, 2)); |
| } |
| return condition; |
| }; |
| |
| |
| /** |
| * Fails if goog.asserts.ENABLE_ASSERTS is true. This function is useful in case |
| * when we want to add a check in the unreachable area like switch-case |
| * statement: |
| * |
| * <pre> |
| * switch(type) { |
| * case FOO: doSomething(); break; |
| * case BAR: doSomethingElse(); break; |
| * default: goog.assert.fail('Unrecognized type: ' + type); |
| * // We have only 2 types - "default:" section is unreachable code. |
| * } |
| * </pre> |
| * |
| * @param {string=} opt_message Error message in case of failure. |
| * @param {...*} var_args The items to substitute into the failure message. |
| * @throws {goog.asserts.AssertionError} Failure. |
| */ |
| goog.asserts.fail = function(opt_message, var_args) { |
| if (goog.asserts.ENABLE_ASSERTS) { |
| goog.asserts.errorHandler_(new goog.asserts.AssertionError( |
| 'Failure' + (opt_message ? ': ' + opt_message : ''), |
| Array.prototype.slice.call(arguments, 1))); |
| } |
| }; |
| |
| |
| /** |
| * Checks if the value is a number if goog.asserts.ENABLE_ASSERTS is true. |
| * @param {*} value The value to check. |
| * @param {string=} opt_message Error message in case of failure. |
| * @param {...*} var_args The items to substitute into the failure message. |
| * @return {number} The value, guaranteed to be a number when asserts enabled. |
| * @throws {goog.asserts.AssertionError} When the value is not a number. |
| */ |
| goog.asserts.assertNumber = function(value, opt_message, var_args) { |
| if (goog.asserts.ENABLE_ASSERTS && !goog.isNumber(value)) { |
| goog.asserts.doAssertFailure_('Expected number but got %s: %s.', |
| [goog.typeOf(value), value], opt_message, |
| Array.prototype.slice.call(arguments, 2)); |
| } |
| return /** @type {number} */ (value); |
| }; |
| |
| |
| /** |
| * Checks if the value is a string if goog.asserts.ENABLE_ASSERTS is true. |
| * @param {*} value The value to check. |
| * @param {string=} opt_message Error message in case of failure. |
| * @param {...*} var_args The items to substitute into the failure message. |
| * @return {string} The value, guaranteed to be a string when asserts enabled. |
| * @throws {goog.asserts.AssertionError} When the value is not a string. |
| */ |
| goog.asserts.assertString = function(value, opt_message, var_args) { |
| if (goog.asserts.ENABLE_ASSERTS && !goog.isString(value)) { |
| goog.asserts.doAssertFailure_('Expected string but got %s: %s.', |
| [goog.typeOf(value), value], opt_message, |
| Array.prototype.slice.call(arguments, 2)); |
| } |
| return /** @type {string} */ (value); |
| }; |
| |
| |
| /** |
| * Checks if the value is a function if goog.asserts.ENABLE_ASSERTS is true. |
| * @param {*} value The value to check. |
| * @param {string=} opt_message Error message in case of failure. |
| * @param {...*} var_args The items to substitute into the failure message. |
| * @return {!Function} The value, guaranteed to be a function when asserts |
| * enabled. |
| * @throws {goog.asserts.AssertionError} When the value is not a function. |
| */ |
| goog.asserts.assertFunction = function(value, opt_message, var_args) { |
| if (goog.asserts.ENABLE_ASSERTS && !goog.isFunction(value)) { |
| goog.asserts.doAssertFailure_('Expected function but got %s: %s.', |
| [goog.typeOf(value), value], opt_message, |
| Array.prototype.slice.call(arguments, 2)); |
| } |
| return /** @type {!Function} */ (value); |
| }; |
| |
| |
| /** |
| * Checks if the value is an Object if goog.asserts.ENABLE_ASSERTS is true. |
| * @param {*} value The value to check. |
| * @param {string=} opt_message Error message in case of failure. |
| * @param {...*} var_args The items to substitute into the failure message. |
| * @return {!Object} The value, guaranteed to be a non-null object. |
| * @throws {goog.asserts.AssertionError} When the value is not an object. |
| */ |
| goog.asserts.assertObject = function(value, opt_message, var_args) { |
| if (goog.asserts.ENABLE_ASSERTS && !goog.isObject(value)) { |
| goog.asserts.doAssertFailure_('Expected object but got %s: %s.', |
| [goog.typeOf(value), value], |
| opt_message, Array.prototype.slice.call(arguments, 2)); |
| } |
| return /** @type {!Object} */ (value); |
| }; |
| |
| |
| /** |
| * Checks if the value is an Array if goog.asserts.ENABLE_ASSERTS is true. |
| * @param {*} value The value to check. |
| * @param {string=} opt_message Error message in case of failure. |
| * @param {...*} var_args The items to substitute into the failure message. |
| * @return {!Array<?>} The value, guaranteed to be a non-null array. |
| * @throws {goog.asserts.AssertionError} When the value is not an array. |
| */ |
| goog.asserts.assertArray = function(value, opt_message, var_args) { |
| if (goog.asserts.ENABLE_ASSERTS && !goog.isArray(value)) { |
| goog.asserts.doAssertFailure_('Expected array but got %s: %s.', |
| [goog.typeOf(value), value], opt_message, |
| Array.prototype.slice.call(arguments, 2)); |
| } |
| return /** @type {!Array<?>} */ (value); |
| }; |
| |
| |
| /** |
| * Checks if the value is a boolean if goog.asserts.ENABLE_ASSERTS is true. |
| * @param {*} value The value to check. |
| * @param {string=} opt_message Error message in case of failure. |
| * @param {...*} var_args The items to substitute into the failure message. |
| * @return {boolean} The value, guaranteed to be a boolean when asserts are |
| * enabled. |
| * @throws {goog.asserts.AssertionError} When the value is not a boolean. |
| */ |
| goog.asserts.assertBoolean = function(value, opt_message, var_args) { |
| if (goog.asserts.ENABLE_ASSERTS && !goog.isBoolean(value)) { |
| goog.asserts.doAssertFailure_('Expected boolean but got %s: %s.', |
| [goog.typeOf(value), value], opt_message, |
| Array.prototype.slice.call(arguments, 2)); |
| } |
| return /** @type {boolean} */ (value); |
| }; |
| |
| |
| /** |
| * Checks if the value is a DOM Element if goog.asserts.ENABLE_ASSERTS is true. |
| * @param {*} value The value to check. |
| * @param {string=} opt_message Error message in case of failure. |
| * @param {...*} var_args The items to substitute into the failure message. |
| * @return {!Element} The value, likely to be a DOM Element when asserts are |
| * enabled. |
| * @throws {goog.asserts.AssertionError} When the value is not an Element. |
| */ |
| goog.asserts.assertElement = function(value, opt_message, var_args) { |
| if (goog.asserts.ENABLE_ASSERTS && (!goog.isObject(value) || |
| value.nodeType != goog.dom.NodeType.ELEMENT)) { |
| goog.asserts.doAssertFailure_('Expected Element but got %s: %s.', |
| [goog.typeOf(value), value], opt_message, |
| Array.prototype.slice.call(arguments, 2)); |
| } |
| return /** @type {!Element} */ (value); |
| }; |
| |
| |
| /** |
| * Checks if the value is an instance of the user-defined type if |
| * goog.asserts.ENABLE_ASSERTS is true. |
| * |
| * The compiler may tighten the type returned by this function. |
| * |
| * @param {*} value The value to check. |
| * @param {function(new: T, ...)} type A user-defined constructor. |
| * @param {string=} opt_message Error message in case of failure. |
| * @param {...*} var_args The items to substitute into the failure message. |
| * @throws {goog.asserts.AssertionError} When the value is not an instance of |
| * type. |
| * @return {T} |
| * @template T |
| */ |
| goog.asserts.assertInstanceof = function(value, type, opt_message, var_args) { |
| if (goog.asserts.ENABLE_ASSERTS && !(value instanceof type)) { |
| goog.asserts.doAssertFailure_('Expected instanceof %s but got %s.', |
| [goog.asserts.getType_(type), goog.asserts.getType_(value)], |
| opt_message, Array.prototype.slice.call(arguments, 3)); |
| } |
| return value; |
| }; |
| |
| |
| /** |
| * Checks that no enumerable keys are present in Object.prototype. Such keys |
| * would break most code that use {@code for (var ... in ...)} loops. |
| */ |
| goog.asserts.assertObjectPrototypeIsIntact = function() { |
| for (var key in Object.prototype) { |
| goog.asserts.fail(key + ' should not be enumerable in Object.prototype.'); |
| } |
| }; |
| |
| |
| /** |
| * Returns the type of a value. If a constructor is passed, and a suitable |
| * string cannot be found, 'unknown type name' will be returned. |
| * @param {*} value A constructor, object, or primitive. |
| * @return {string} The best display name for the value, or 'unknown type name'. |
| * @private |
| */ |
| goog.asserts.getType_ = function(value) { |
| if (value instanceof Function) { |
| return value.displayName || value.name || 'unknown type name'; |
| } else if (value instanceof Object) { |
| return value.constructor.displayName || value.constructor.name || |
| Object.prototype.toString.call(value); |
| } else { |
| return value === null ? 'null' : typeof value; |
| } |
| }; |