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655 lines
20 KiB
655 lines
20 KiB
'use strict'; |
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|
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Object.defineProperty(exports, '__esModule', { |
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value: true |
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}); |
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exports.cleanupSemantic = |
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exports.Diff = |
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exports.DIFF_INSERT = |
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exports.DIFF_EQUAL = |
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exports.DIFF_DELETE = |
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void 0; |
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function _defineProperty(obj, key, value) { |
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if (key in obj) { |
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Object.defineProperty(obj, key, { |
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value: value, |
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enumerable: true, |
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configurable: true, |
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writable: true |
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}); |
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} else { |
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obj[key] = value; |
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} |
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return obj; |
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} |
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/** |
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* Diff Match and Patch |
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* Copyright 2018 The diff-match-patch Authors. |
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* https://github.com/google/diff-match-patch |
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* |
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* Licensed under the Apache License, Version 2.0 (the "License"); |
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* you may not use this file except in compliance with the License. |
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* You may obtain a copy of the License at |
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* |
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* http://www.apache.org/licenses/LICENSE-2.0 |
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* |
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* Unless required by applicable law or agreed to in writing, software |
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* distributed under the License is distributed on an "AS IS" BASIS, |
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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* See the License for the specific language governing permissions and |
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* limitations under the License. |
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*/ |
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|
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/** |
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* @fileoverview Computes the difference between two texts to create a patch. |
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* Applies the patch onto another text, allowing for errors. |
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* @author fraser@google.com (Neil Fraser) |
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*/ |
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/** |
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* CHANGES by pedrottimark to diff_match_patch_uncompressed.ts file: |
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* |
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* 1. Delete anything not needed to use diff_cleanupSemantic method |
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* 2. Convert from prototype properties to var declarations |
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* 3. Convert Diff to class from constructor and prototype |
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* 4. Add type annotations for arguments and return values |
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* 5. Add exports |
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*/ |
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/** |
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* The data structure representing a diff is an array of tuples: |
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* [[DIFF_DELETE, 'Hello'], [DIFF_INSERT, 'Goodbye'], [DIFF_EQUAL, ' world.']] |
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* which means: delete 'Hello', add 'Goodbye' and keep ' world.' |
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*/ |
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var DIFF_DELETE = -1; |
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exports.DIFF_DELETE = DIFF_DELETE; |
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var DIFF_INSERT = 1; |
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exports.DIFF_INSERT = DIFF_INSERT; |
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var DIFF_EQUAL = 0; |
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/** |
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* Class representing one diff tuple. |
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* Attempts to look like a two-element array (which is what this used to be). |
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* @param {number} op Operation, one of: DIFF_DELETE, DIFF_INSERT, DIFF_EQUAL. |
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* @param {string} text Text to be deleted, inserted, or retained. |
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* @constructor |
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*/ |
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exports.DIFF_EQUAL = DIFF_EQUAL; |
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class Diff { |
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constructor(op, text) { |
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_defineProperty(this, 0, void 0); |
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_defineProperty(this, 1, void 0); |
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this[0] = op; |
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this[1] = text; |
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} |
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} |
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/** |
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* Determine the common prefix of two strings. |
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* @param {string} text1 First string. |
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* @param {string} text2 Second string. |
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* @return {number} The number of characters common to the start of each |
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* string. |
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*/ |
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exports.Diff = Diff; |
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var diff_commonPrefix = function (text1, text2) { |
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// Quick check for common null cases. |
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if (!text1 || !text2 || text1.charAt(0) != text2.charAt(0)) { |
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return 0; |
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} // Binary search. |
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// Performance analysis: https://neil.fraser.name/news/2007/10/09/ |
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var pointermin = 0; |
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var pointermax = Math.min(text1.length, text2.length); |
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var pointermid = pointermax; |
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var pointerstart = 0; |
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while (pointermin < pointermid) { |
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if ( |
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text1.substring(pointerstart, pointermid) == |
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text2.substring(pointerstart, pointermid) |
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) { |
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pointermin = pointermid; |
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pointerstart = pointermin; |
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} else { |
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pointermax = pointermid; |
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} |
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pointermid = Math.floor((pointermax - pointermin) / 2 + pointermin); |
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} |
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return pointermid; |
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}; |
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/** |
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* Determine the common suffix of two strings. |
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* @param {string} text1 First string. |
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* @param {string} text2 Second string. |
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* @return {number} The number of characters common to the end of each string. |
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*/ |
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var diff_commonSuffix = function (text1, text2) { |
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// Quick check for common null cases. |
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if ( |
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!text1 || |
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!text2 || |
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text1.charAt(text1.length - 1) != text2.charAt(text2.length - 1) |
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) { |
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return 0; |
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} // Binary search. |
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// Performance analysis: https://neil.fraser.name/news/2007/10/09/ |
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var pointermin = 0; |
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var pointermax = Math.min(text1.length, text2.length); |
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var pointermid = pointermax; |
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var pointerend = 0; |
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while (pointermin < pointermid) { |
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if ( |
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text1.substring(text1.length - pointermid, text1.length - pointerend) == |
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text2.substring(text2.length - pointermid, text2.length - pointerend) |
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) { |
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pointermin = pointermid; |
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pointerend = pointermin; |
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} else { |
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pointermax = pointermid; |
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} |
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pointermid = Math.floor((pointermax - pointermin) / 2 + pointermin); |
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} |
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return pointermid; |
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}; |
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/** |
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* Determine if the suffix of one string is the prefix of another. |
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* @param {string} text1 First string. |
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* @param {string} text2 Second string. |
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* @return {number} The number of characters common to the end of the first |
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* string and the start of the second string. |
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* @private |
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*/ |
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var diff_commonOverlap_ = function (text1, text2) { |
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// Cache the text lengths to prevent multiple calls. |
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var text1_length = text1.length; |
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var text2_length = text2.length; // Eliminate the null case. |
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if (text1_length == 0 || text2_length == 0) { |
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return 0; |
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} // Truncate the longer string. |
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if (text1_length > text2_length) { |
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text1 = text1.substring(text1_length - text2_length); |
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} else if (text1_length < text2_length) { |
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text2 = text2.substring(0, text1_length); |
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} |
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var text_length = Math.min(text1_length, text2_length); // Quick check for the worst case. |
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if (text1 == text2) { |
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return text_length; |
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} // Start by looking for a single character match |
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// and increase length until no match is found. |
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// Performance analysis: https://neil.fraser.name/news/2010/11/04/ |
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var best = 0; |
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var length = 1; |
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while (true) { |
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var pattern = text1.substring(text_length - length); |
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var found = text2.indexOf(pattern); |
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if (found == -1) { |
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return best; |
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} |
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length += found; |
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if ( |
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found == 0 || |
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text1.substring(text_length - length) == text2.substring(0, length) |
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) { |
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best = length; |
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length++; |
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} |
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} |
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}; |
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/** |
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* Reduce the number of edits by eliminating semantically trivial equalities. |
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* @param {!Array.<!diff_match_patch.Diff>} diffs Array of diff tuples. |
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*/ |
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var diff_cleanupSemantic = function (diffs) { |
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var changes = false; |
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var equalities = []; // Stack of indices where equalities are found. |
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var equalitiesLength = 0; // Keeping our own length var is faster in JS. |
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/** @type {?string} */ |
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var lastEquality = null; // Always equal to diffs[equalities[equalitiesLength - 1]][1] |
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var pointer = 0; // Index of current position. |
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// Number of characters that changed prior to the equality. |
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var length_insertions1 = 0; |
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var length_deletions1 = 0; // Number of characters that changed after the equality. |
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var length_insertions2 = 0; |
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var length_deletions2 = 0; |
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while (pointer < diffs.length) { |
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if (diffs[pointer][0] == DIFF_EQUAL) { |
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// Equality found. |
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equalities[equalitiesLength++] = pointer; |
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length_insertions1 = length_insertions2; |
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length_deletions1 = length_deletions2; |
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length_insertions2 = 0; |
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length_deletions2 = 0; |
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lastEquality = diffs[pointer][1]; |
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} else { |
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// An insertion or deletion. |
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if (diffs[pointer][0] == DIFF_INSERT) { |
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length_insertions2 += diffs[pointer][1].length; |
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} else { |
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length_deletions2 += diffs[pointer][1].length; |
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} // Eliminate an equality that is smaller or equal to the edits on both |
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// sides of it. |
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if ( |
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lastEquality && |
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lastEquality.length <= |
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Math.max(length_insertions1, length_deletions1) && |
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lastEquality.length <= Math.max(length_insertions2, length_deletions2) |
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) { |
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// Duplicate record. |
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diffs.splice( |
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equalities[equalitiesLength - 1], |
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0, |
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new Diff(DIFF_DELETE, lastEquality) |
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); // Change second copy to insert. |
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diffs[equalities[equalitiesLength - 1] + 1][0] = DIFF_INSERT; // Throw away the equality we just deleted. |
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equalitiesLength--; // Throw away the previous equality (it needs to be reevaluated). |
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equalitiesLength--; |
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pointer = equalitiesLength > 0 ? equalities[equalitiesLength - 1] : -1; |
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length_insertions1 = 0; // Reset the counters. |
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length_deletions1 = 0; |
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length_insertions2 = 0; |
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length_deletions2 = 0; |
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lastEquality = null; |
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changes = true; |
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} |
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} |
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pointer++; |
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} // Normalize the diff. |
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if (changes) { |
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diff_cleanupMerge(diffs); |
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} |
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diff_cleanupSemanticLossless(diffs); // Find any overlaps between deletions and insertions. |
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// e.g: <del>abcxxx</del><ins>xxxdef</ins> |
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// -> <del>abc</del>xxx<ins>def</ins> |
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// e.g: <del>xxxabc</del><ins>defxxx</ins> |
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// -> <ins>def</ins>xxx<del>abc</del> |
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// Only extract an overlap if it is as big as the edit ahead or behind it. |
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pointer = 1; |
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while (pointer < diffs.length) { |
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if ( |
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diffs[pointer - 1][0] == DIFF_DELETE && |
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diffs[pointer][0] == DIFF_INSERT |
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) { |
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var deletion = diffs[pointer - 1][1]; |
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var insertion = diffs[pointer][1]; |
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var overlap_length1 = diff_commonOverlap_(deletion, insertion); |
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var overlap_length2 = diff_commonOverlap_(insertion, deletion); |
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if (overlap_length1 >= overlap_length2) { |
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if ( |
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overlap_length1 >= deletion.length / 2 || |
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overlap_length1 >= insertion.length / 2 |
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) { |
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// Overlap found. Insert an equality and trim the surrounding edits. |
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diffs.splice( |
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pointer, |
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0, |
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new Diff(DIFF_EQUAL, insertion.substring(0, overlap_length1)) |
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); |
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diffs[pointer - 1][1] = deletion.substring( |
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0, |
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deletion.length - overlap_length1 |
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); |
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diffs[pointer + 1][1] = insertion.substring(overlap_length1); |
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pointer++; |
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} |
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} else { |
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if ( |
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overlap_length2 >= deletion.length / 2 || |
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overlap_length2 >= insertion.length / 2 |
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) { |
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// Reverse overlap found. |
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// Insert an equality and swap and trim the surrounding edits. |
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diffs.splice( |
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pointer, |
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0, |
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new Diff(DIFF_EQUAL, deletion.substring(0, overlap_length2)) |
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); |
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diffs[pointer - 1][0] = DIFF_INSERT; |
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diffs[pointer - 1][1] = insertion.substring( |
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0, |
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insertion.length - overlap_length2 |
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); |
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diffs[pointer + 1][0] = DIFF_DELETE; |
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diffs[pointer + 1][1] = deletion.substring(overlap_length2); |
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pointer++; |
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} |
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} |
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pointer++; |
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} |
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pointer++; |
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} |
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}; |
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/** |
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* Look for single edits surrounded on both sides by equalities |
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* which can be shifted sideways to align the edit to a word boundary. |
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* e.g: The c<ins>at c</ins>ame. -> The <ins>cat </ins>came. |
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* @param {!Array.<!diff_match_patch.Diff>} diffs Array of diff tuples. |
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*/ |
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exports.cleanupSemantic = diff_cleanupSemantic; |
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var diff_cleanupSemanticLossless = function (diffs) { |
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/** |
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* Given two strings, compute a score representing whether the internal |
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* boundary falls on logical boundaries. |
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* Scores range from 6 (best) to 0 (worst). |
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* Closure, but does not reference any external variables. |
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* @param {string} one First string. |
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* @param {string} two Second string. |
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* @return {number} The score. |
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* @private |
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*/ |
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function diff_cleanupSemanticScore_(one, two) { |
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if (!one || !two) { |
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// Edges are the best. |
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return 6; |
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} // Each port of this function behaves slightly differently due to |
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// subtle differences in each language's definition of things like |
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// 'whitespace'. Since this function's purpose is largely cosmetic, |
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// the choice has been made to use each language's native features |
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// rather than force total conformity. |
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var char1 = one.charAt(one.length - 1); |
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var char2 = two.charAt(0); |
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var nonAlphaNumeric1 = char1.match(nonAlphaNumericRegex_); |
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var nonAlphaNumeric2 = char2.match(nonAlphaNumericRegex_); |
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var whitespace1 = nonAlphaNumeric1 && char1.match(whitespaceRegex_); |
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var whitespace2 = nonAlphaNumeric2 && char2.match(whitespaceRegex_); |
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var lineBreak1 = whitespace1 && char1.match(linebreakRegex_); |
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var lineBreak2 = whitespace2 && char2.match(linebreakRegex_); |
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var blankLine1 = lineBreak1 && one.match(blanklineEndRegex_); |
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var blankLine2 = lineBreak2 && two.match(blanklineStartRegex_); |
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if (blankLine1 || blankLine2) { |
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// Five points for blank lines. |
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return 5; |
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} else if (lineBreak1 || lineBreak2) { |
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// Four points for line breaks. |
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return 4; |
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} else if (nonAlphaNumeric1 && !whitespace1 && whitespace2) { |
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// Three points for end of sentences. |
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return 3; |
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} else if (whitespace1 || whitespace2) { |
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// Two points for whitespace. |
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return 2; |
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} else if (nonAlphaNumeric1 || nonAlphaNumeric2) { |
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// One point for non-alphanumeric. |
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return 1; |
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} |
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return 0; |
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} |
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var pointer = 1; // Intentionally ignore the first and last element (don't need checking). |
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while (pointer < diffs.length - 1) { |
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if ( |
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diffs[pointer - 1][0] == DIFF_EQUAL && |
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diffs[pointer + 1][0] == DIFF_EQUAL |
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) { |
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// This is a single edit surrounded by equalities. |
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var equality1 = diffs[pointer - 1][1]; |
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var edit = diffs[pointer][1]; |
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var equality2 = diffs[pointer + 1][1]; // First, shift the edit as far left as possible. |
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var commonOffset = diff_commonSuffix(equality1, edit); |
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if (commonOffset) { |
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var commonString = edit.substring(edit.length - commonOffset); |
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equality1 = equality1.substring(0, equality1.length - commonOffset); |
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edit = commonString + edit.substring(0, edit.length - commonOffset); |
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equality2 = commonString + equality2; |
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} // Second, step character by character right, looking for the best fit. |
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var bestEquality1 = equality1; |
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var bestEdit = edit; |
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var bestEquality2 = equality2; |
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var bestScore = |
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diff_cleanupSemanticScore_(equality1, edit) + |
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diff_cleanupSemanticScore_(edit, equality2); |
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while (edit.charAt(0) === equality2.charAt(0)) { |
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equality1 += edit.charAt(0); |
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edit = edit.substring(1) + equality2.charAt(0); |
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equality2 = equality2.substring(1); |
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var score = |
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diff_cleanupSemanticScore_(equality1, edit) + |
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diff_cleanupSemanticScore_(edit, equality2); // The >= encourages trailing rather than leading whitespace on edits. |
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if (score >= bestScore) { |
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bestScore = score; |
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bestEquality1 = equality1; |
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bestEdit = edit; |
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bestEquality2 = equality2; |
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} |
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} |
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if (diffs[pointer - 1][1] != bestEquality1) { |
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// We have an improvement, save it back to the diff. |
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if (bestEquality1) { |
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diffs[pointer - 1][1] = bestEquality1; |
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} else { |
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diffs.splice(pointer - 1, 1); |
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pointer--; |
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} |
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diffs[pointer][1] = bestEdit; |
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if (bestEquality2) { |
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diffs[pointer + 1][1] = bestEquality2; |
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} else { |
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diffs.splice(pointer + 1, 1); |
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pointer--; |
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} |
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} |
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} |
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pointer++; |
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} |
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}; // Define some regex patterns for matching boundaries. |
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var nonAlphaNumericRegex_ = /[^a-zA-Z0-9]/; |
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var whitespaceRegex_ = /\s/; |
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var linebreakRegex_ = /[\r\n]/; |
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var blanklineEndRegex_ = /\n\r?\n$/; |
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var blanklineStartRegex_ = /^\r?\n\r?\n/; |
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/** |
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* Reorder and merge like edit sections. Merge equalities. |
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* Any edit section can move as long as it doesn't cross an equality. |
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* @param {!Array.<!diff_match_patch.Diff>} diffs Array of diff tuples. |
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*/ |
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var diff_cleanupMerge = function (diffs) { |
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// Add a dummy entry at the end. |
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diffs.push(new Diff(DIFF_EQUAL, '')); |
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var pointer = 0; |
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var count_delete = 0; |
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var count_insert = 0; |
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var text_delete = ''; |
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var text_insert = ''; |
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var commonlength; |
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while (pointer < diffs.length) { |
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switch (diffs[pointer][0]) { |
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case DIFF_INSERT: |
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count_insert++; |
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text_insert += diffs[pointer][1]; |
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pointer++; |
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break; |
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|
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case DIFF_DELETE: |
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count_delete++; |
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text_delete += diffs[pointer][1]; |
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pointer++; |
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break; |
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|
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case DIFF_EQUAL: |
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// Upon reaching an equality, check for prior redundancies. |
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if (count_delete + count_insert > 1) { |
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if (count_delete !== 0 && count_insert !== 0) { |
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// Factor out any common prefixies. |
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commonlength = diff_commonPrefix(text_insert, text_delete); |
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|
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if (commonlength !== 0) { |
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if ( |
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pointer - count_delete - count_insert > 0 && |
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diffs[pointer - count_delete - count_insert - 1][0] == |
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DIFF_EQUAL |
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) { |
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diffs[pointer - count_delete - count_insert - 1][1] += |
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text_insert.substring(0, commonlength); |
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} else { |
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diffs.splice( |
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0, |
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0, |
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new Diff(DIFF_EQUAL, text_insert.substring(0, commonlength)) |
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); |
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pointer++; |
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} |
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text_insert = text_insert.substring(commonlength); |
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text_delete = text_delete.substring(commonlength); |
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} // Factor out any common suffixies. |
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commonlength = diff_commonSuffix(text_insert, text_delete); |
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|
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if (commonlength !== 0) { |
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diffs[pointer][1] = |
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text_insert.substring(text_insert.length - commonlength) + |
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diffs[pointer][1]; |
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text_insert = text_insert.substring( |
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0, |
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text_insert.length - commonlength |
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); |
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text_delete = text_delete.substring( |
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0, |
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text_delete.length - commonlength |
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); |
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} |
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} // Delete the offending records and add the merged ones. |
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|
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pointer -= count_delete + count_insert; |
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diffs.splice(pointer, count_delete + count_insert); |
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|
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if (text_delete.length) { |
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diffs.splice(pointer, 0, new Diff(DIFF_DELETE, text_delete)); |
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pointer++; |
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} |
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|
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if (text_insert.length) { |
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diffs.splice(pointer, 0, new Diff(DIFF_INSERT, text_insert)); |
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pointer++; |
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} |
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|
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pointer++; |
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} else if (pointer !== 0 && diffs[pointer - 1][0] == DIFF_EQUAL) { |
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// Merge this equality with the previous one. |
|
diffs[pointer - 1][1] += diffs[pointer][1]; |
|
diffs.splice(pointer, 1); |
|
} else { |
|
pointer++; |
|
} |
|
|
|
count_insert = 0; |
|
count_delete = 0; |
|
text_delete = ''; |
|
text_insert = ''; |
|
break; |
|
} |
|
} |
|
|
|
if (diffs[diffs.length - 1][1] === '') { |
|
diffs.pop(); // Remove the dummy entry at the end. |
|
} // Second pass: look for single edits surrounded on both sides by equalities |
|
// which can be shifted sideways to eliminate an equality. |
|
// e.g: A<ins>BA</ins>C -> <ins>AB</ins>AC |
|
|
|
var changes = false; |
|
pointer = 1; // Intentionally ignore the first and last element (don't need checking). |
|
|
|
while (pointer < diffs.length - 1) { |
|
if ( |
|
diffs[pointer - 1][0] == DIFF_EQUAL && |
|
diffs[pointer + 1][0] == DIFF_EQUAL |
|
) { |
|
// This is a single edit surrounded by equalities. |
|
if ( |
|
diffs[pointer][1].substring( |
|
diffs[pointer][1].length - diffs[pointer - 1][1].length |
|
) == diffs[pointer - 1][1] |
|
) { |
|
// Shift the edit over the previous equality. |
|
diffs[pointer][1] = |
|
diffs[pointer - 1][1] + |
|
diffs[pointer][1].substring( |
|
0, |
|
diffs[pointer][1].length - diffs[pointer - 1][1].length |
|
); |
|
diffs[pointer + 1][1] = diffs[pointer - 1][1] + diffs[pointer + 1][1]; |
|
diffs.splice(pointer - 1, 1); |
|
changes = true; |
|
} else if ( |
|
diffs[pointer][1].substring(0, diffs[pointer + 1][1].length) == |
|
diffs[pointer + 1][1] |
|
) { |
|
// Shift the edit over the next equality. |
|
diffs[pointer - 1][1] += diffs[pointer + 1][1]; |
|
diffs[pointer][1] = |
|
diffs[pointer][1].substring(diffs[pointer + 1][1].length) + |
|
diffs[pointer + 1][1]; |
|
diffs.splice(pointer + 1, 1); |
|
changes = true; |
|
} |
|
} |
|
|
|
pointer++; |
|
} // If shifts were made, the diff needs reordering and another shift sweep. |
|
|
|
if (changes) { |
|
diff_cleanupMerge(diffs); |
|
} |
|
};
|
|
|