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JavaScript

'use strict';
Object.defineProperty(exports, '__esModule', {
value: true
});
exports.cleanupSemantic = exports.DIFF_INSERT = exports.DIFF_DELETE = exports.DIFF_EQUAL = exports.Diff = 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.<!diff_match_patch.Diff>} 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: <del>abcxxx</del><ins>xxxdef</ins>
// -> <del>abc</del>xxx<ins>def</ins>
// e.g: <del>xxxabc</del><ins>defxxx</ins>
// -> <ins>def</ins>xxx<del>abc</del>
// 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 c<ins>at c</ins>ame. -> The <ins>cat </ins>came.
* @param {!Array.<!diff_match_patch.Diff>} 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.<!diff_match_patch.Diff>} 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: 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);
}
};