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