| // Copyright 2007 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 DOM pattern to match any children of a tag, and |
| * specifically collect those that match a child pattern. |
| * |
| * @author robbyw@google.com (Robby Walker) |
| */ |
| |
| goog.provide('goog.dom.pattern.ChildMatches'); |
| |
| goog.require('goog.dom.pattern.AllChildren'); |
| goog.require('goog.dom.pattern.MatchType'); |
| |
| |
| |
| /** |
| * Pattern object that matches any nodes at or below the current tree depth. |
| * |
| * @param {goog.dom.pattern.AbstractPattern} childPattern Pattern to collect |
| * child matches of. |
| * @param {number=} opt_minimumMatches Enforce a minimum nuber of matches. |
| * Defaults to 0. |
| * @constructor |
| * @extends {goog.dom.pattern.AllChildren} |
| * @final |
| */ |
| goog.dom.pattern.ChildMatches = function(childPattern, opt_minimumMatches) { |
| this.childPattern_ = childPattern; |
| this.matches = []; |
| this.minimumMatches_ = opt_minimumMatches || 0; |
| goog.dom.pattern.AllChildren.call(this); |
| }; |
| goog.inherits(goog.dom.pattern.ChildMatches, goog.dom.pattern.AllChildren); |
| |
| |
| /** |
| * Array of matched child nodes. |
| * |
| * @type {Array<Node>} |
| */ |
| goog.dom.pattern.ChildMatches.prototype.matches; |
| |
| |
| /** |
| * Minimum number of matches. |
| * |
| * @type {number} |
| * @private |
| */ |
| goog.dom.pattern.ChildMatches.prototype.minimumMatches_ = 0; |
| |
| |
| /** |
| * The child pattern to collect matches from. |
| * |
| * @type {goog.dom.pattern.AbstractPattern} |
| * @private |
| */ |
| goog.dom.pattern.ChildMatches.prototype.childPattern_; |
| |
| |
| /** |
| * Whether the pattern has recently matched or failed to match and will need to |
| * be reset when starting a new round of matches. |
| * |
| * @type {boolean} |
| * @private |
| */ |
| goog.dom.pattern.ChildMatches.prototype.needsReset_ = false; |
| |
| |
| /** |
| * Test whether the given token is on the same level. |
| * |
| * @param {Node} token Token to match against. |
| * @param {goog.dom.TagWalkType} type The type of token. |
| * @return {goog.dom.pattern.MatchType} {@code MATCHING} if the token is on the |
| * same level or deeper and {@code BACKTRACK_MATCH} if not. |
| * @override |
| */ |
| goog.dom.pattern.ChildMatches.prototype.matchToken = function(token, type) { |
| // Defer resets so we maintain our matches array until the last possible time. |
| if (this.needsReset_) { |
| this.reset(); |
| } |
| |
| // Call the super-method to ensure we stay in the child tree. |
| var status = |
| goog.dom.pattern.AllChildren.prototype.matchToken.apply(this, arguments); |
| |
| switch (status) { |
| case goog.dom.pattern.MatchType.MATCHING: |
| var backtrack = false; |
| |
| switch (this.childPattern_.matchToken(token, type)) { |
| case goog.dom.pattern.MatchType.BACKTRACK_MATCH: |
| backtrack = true; |
| case goog.dom.pattern.MatchType.MATCH: |
| // Collect the match. |
| this.matches.push(this.childPattern_.matchedNode); |
| break; |
| |
| default: |
| // Keep trying if we haven't hit a terminal state. |
| break; |
| } |
| |
| if (backtrack) { |
| // The only interesting result is a MATCH, since BACKTRACK_MATCH means |
| // we are hitting an infinite loop on something like a Repeat(0). |
| if (this.childPattern_.matchToken(token, type) == |
| goog.dom.pattern.MatchType.MATCH) { |
| this.matches.push(this.childPattern_.matchedNode); |
| } |
| } |
| return goog.dom.pattern.MatchType.MATCHING; |
| |
| case goog.dom.pattern.MatchType.BACKTRACK_MATCH: |
| // TODO(robbyw): this should return something like BACKTRACK_NO_MATCH |
| // when we don't meet our minimum. |
| this.needsReset_ = true; |
| return (this.matches.length >= this.minimumMatches_) ? |
| goog.dom.pattern.MatchType.BACKTRACK_MATCH : |
| goog.dom.pattern.MatchType.NO_MATCH; |
| |
| default: |
| this.needsReset_ = true; |
| return status; |
| } |
| }; |
| |
| |
| /** |
| * Reset any internal state this pattern keeps. |
| * @override |
| */ |
| goog.dom.pattern.ChildMatches.prototype.reset = function() { |
| this.needsReset_ = false; |
| this.matches.length = 0; |
| this.childPattern_.reset(); |
| goog.dom.pattern.AllChildren.prototype.reset.call(this); |
| }; |