600 lines
20 KiB
JavaScript
600 lines
20 KiB
JavaScript
'use strict';
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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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/**
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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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* @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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0;
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1;
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constructor(op, text) {
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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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}
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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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}
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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;
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// 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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}
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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);
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// Quick check for the worst case.
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if (text1 == text2) {
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return text_length;
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}
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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;
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// 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;
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// 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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}
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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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);
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// Change second copy to insert.
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diffs[equalities[equalitiesLength - 1] + 1][0] = DIFF_INSERT;
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// Throw away the equality we just deleted.
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equalitiesLength--;
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// 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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}
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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);
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// 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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}
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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;
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// 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];
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// 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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}
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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);
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// 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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};
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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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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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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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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))
|
|
);
|
|
pointer++;
|
|
}
|
|
text_insert = text_insert.substring(commonlength);
|
|
text_delete = text_delete.substring(commonlength);
|
|
}
|
|
// Factor out any common suffixies.
|
|
commonlength = diff_commonSuffix(text_insert, text_delete);
|
|
if (commonlength !== 0) {
|
|
diffs[pointer][1] =
|
|
text_insert.substring(text_insert.length - commonlength) +
|
|
diffs[pointer][1];
|
|
text_insert = text_insert.substring(
|
|
0,
|
|
text_insert.length - commonlength
|
|
);
|
|
text_delete = text_delete.substring(
|
|
0,
|
|
text_delete.length - commonlength
|
|
);
|
|
}
|
|
}
|
|
// Delete the offending records and add the merged ones.
|
|
pointer -= count_delete + count_insert;
|
|
diffs.splice(pointer, count_delete + count_insert);
|
|
if (text_delete.length) {
|
|
diffs.splice(pointer, 0, new Diff(DIFF_DELETE, text_delete));
|
|
pointer++;
|
|
}
|
|
if (text_insert.length) {
|
|
diffs.splice(pointer, 0, new Diff(DIFF_INSERT, text_insert));
|
|
pointer++;
|
|
}
|
|
pointer++;
|
|
} else if (pointer !== 0 && diffs[pointer - 1][0] == DIFF_EQUAL) {
|
|
// 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);
|
|
}
|
|
};
|