620 lines
20 KiB
JavaScript
620 lines
20 KiB
JavaScript
/* See LICENSE file for terms of use */
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/*
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* Text diff implementation.
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*
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* This library supports the following APIS:
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* JsDiff.diffChars: Character by character diff
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* JsDiff.diffWords: Word (as defined by \b regex) diff which ignores whitespace
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* JsDiff.diffLines: Line based diff
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*
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* JsDiff.diffCss: Diff targeted at CSS content
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*
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* These methods are based on the implementation proposed in
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* "An O(ND) Difference Algorithm and its Variations" (Myers, 1986).
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* http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.4.6927
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*/
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(function(global, undefined) {
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var objectPrototypeToString = Object.prototype.toString;
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/*istanbul ignore next*/
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function map(arr, mapper, that) {
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if (Array.prototype.map) {
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return Array.prototype.map.call(arr, mapper, that);
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}
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var other = new Array(arr.length);
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for (var i = 0, n = arr.length; i < n; i++) {
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other[i] = mapper.call(that, arr[i], i, arr);
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}
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return other;
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}
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function clonePath(path) {
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return { newPos: path.newPos, components: path.components.slice(0) };
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}
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function removeEmpty(array) {
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var ret = [];
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for (var i = 0; i < array.length; i++) {
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if (array[i]) {
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ret.push(array[i]);
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}
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}
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return ret;
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}
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function escapeHTML(s) {
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var n = s;
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n = n.replace(/&/g, '&');
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n = n.replace(/</g, '<');
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n = n.replace(/>/g, '>');
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n = n.replace(/"/g, '"');
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return n;
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}
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// This function handles the presence of circular references by bailing out when encountering an
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// object that is already on the "stack" of items being processed.
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function canonicalize(obj, stack, replacementStack) {
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stack = stack || [];
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replacementStack = replacementStack || [];
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var i;
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for (i = 0; i < stack.length; i += 1) {
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if (stack[i] === obj) {
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return replacementStack[i];
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}
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}
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var canonicalizedObj;
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if ('[object Array]' === objectPrototypeToString.call(obj)) {
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stack.push(obj);
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canonicalizedObj = new Array(obj.length);
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replacementStack.push(canonicalizedObj);
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for (i = 0; i < obj.length; i += 1) {
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canonicalizedObj[i] = canonicalize(obj[i], stack, replacementStack);
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}
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stack.pop();
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replacementStack.pop();
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} else if (typeof obj === 'object' && obj !== null) {
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stack.push(obj);
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canonicalizedObj = {};
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replacementStack.push(canonicalizedObj);
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var sortedKeys = [],
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key;
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for (key in obj) {
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sortedKeys.push(key);
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}
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sortedKeys.sort();
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for (i = 0; i < sortedKeys.length; i += 1) {
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key = sortedKeys[i];
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canonicalizedObj[key] = canonicalize(obj[key], stack, replacementStack);
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}
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stack.pop();
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replacementStack.pop();
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} else {
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canonicalizedObj = obj;
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}
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return canonicalizedObj;
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}
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function buildValues(components, newString, oldString, useLongestToken) {
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var componentPos = 0,
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componentLen = components.length,
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newPos = 0,
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oldPos = 0;
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for (; componentPos < componentLen; componentPos++) {
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var component = components[componentPos];
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if (!component.removed) {
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if (!component.added && useLongestToken) {
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var value = newString.slice(newPos, newPos + component.count);
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value = map(value, function(value, i) {
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var oldValue = oldString[oldPos + i];
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return oldValue.length > value.length ? oldValue : value;
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});
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component.value = value.join('');
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} else {
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component.value = newString.slice(newPos, newPos + component.count).join('');
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}
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newPos += component.count;
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// Common case
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if (!component.added) {
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oldPos += component.count;
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}
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} else {
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component.value = oldString.slice(oldPos, oldPos + component.count).join('');
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oldPos += component.count;
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// Reverse add and remove so removes are output first to match common convention
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// The diffing algorithm is tied to add then remove output and this is the simplest
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// route to get the desired output with minimal overhead.
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if (componentPos && components[componentPos - 1].added) {
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var tmp = components[componentPos - 1];
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components[componentPos - 1] = components[componentPos];
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components[componentPos] = tmp;
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}
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}
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}
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return components;
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}
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function Diff(ignoreWhitespace) {
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this.ignoreWhitespace = ignoreWhitespace;
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}
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Diff.prototype = {
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diff: function(oldString, newString, callback) {
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var self = this;
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function done(value) {
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if (callback) {
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setTimeout(function() { callback(undefined, value); }, 0);
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return true;
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} else {
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return value;
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}
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}
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// Handle the identity case (this is due to unrolling editLength == 0
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if (newString === oldString) {
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return done([{ value: newString }]);
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}
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if (!newString) {
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return done([{ value: oldString, removed: true }]);
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}
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if (!oldString) {
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return done([{ value: newString, added: true }]);
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}
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newString = this.tokenize(newString);
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oldString = this.tokenize(oldString);
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var newLen = newString.length, oldLen = oldString.length;
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var editLength = 1;
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var maxEditLength = newLen + oldLen;
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var bestPath = [{ newPos: -1, components: [] }];
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// Seed editLength = 0, i.e. the content starts with the same values
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var oldPos = this.extractCommon(bestPath[0], newString, oldString, 0);
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if (bestPath[0].newPos + 1 >= newLen && oldPos + 1 >= oldLen) {
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// Identity per the equality and tokenizer
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return done([{value: newString.join('')}]);
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}
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// Main worker method. checks all permutations of a given edit length for acceptance.
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function execEditLength() {
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for (var diagonalPath = -1 * editLength; diagonalPath <= editLength; diagonalPath += 2) {
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var basePath;
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var addPath = bestPath[diagonalPath - 1],
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removePath = bestPath[diagonalPath + 1],
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oldPos = (removePath ? removePath.newPos : 0) - diagonalPath;
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if (addPath) {
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// No one else is going to attempt to use this value, clear it
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bestPath[diagonalPath - 1] = undefined;
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}
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var canAdd = addPath && addPath.newPos + 1 < newLen,
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canRemove = removePath && 0 <= oldPos && oldPos < oldLen;
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if (!canAdd && !canRemove) {
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// If this path is a terminal then prune
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bestPath[diagonalPath] = undefined;
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continue;
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}
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// Select the diagonal that we want to branch from. We select the prior
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// path whose position in the new string is the farthest from the origin
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// and does not pass the bounds of the diff graph
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if (!canAdd || (canRemove && addPath.newPos < removePath.newPos)) {
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basePath = clonePath(removePath);
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self.pushComponent(basePath.components, undefined, true);
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} else {
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basePath = addPath; // No need to clone, we've pulled it from the list
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basePath.newPos++;
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self.pushComponent(basePath.components, true, undefined);
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}
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oldPos = self.extractCommon(basePath, newString, oldString, diagonalPath);
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// If we have hit the end of both strings, then we are done
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if (basePath.newPos + 1 >= newLen && oldPos + 1 >= oldLen) {
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return done(buildValues(basePath.components, newString, oldString, self.useLongestToken));
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} else {
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// Otherwise track this path as a potential candidate and continue.
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bestPath[diagonalPath] = basePath;
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}
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}
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editLength++;
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}
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// Performs the length of edit iteration. Is a bit fugly as this has to support the
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// sync and async mode which is never fun. Loops over execEditLength until a value
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// is produced.
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if (callback) {
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(function exec() {
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setTimeout(function() {
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// This should not happen, but we want to be safe.
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/*istanbul ignore next */
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if (editLength > maxEditLength) {
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return callback();
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}
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if (!execEditLength()) {
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exec();
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}
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}, 0);
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}());
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} else {
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while (editLength <= maxEditLength) {
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var ret = execEditLength();
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if (ret) {
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return ret;
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}
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}
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}
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},
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pushComponent: function(components, added, removed) {
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var last = components[components.length - 1];
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if (last && last.added === added && last.removed === removed) {
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// We need to clone here as the component clone operation is just
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// as shallow array clone
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components[components.length - 1] = {count: last.count + 1, added: added, removed: removed };
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} else {
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components.push({count: 1, added: added, removed: removed });
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}
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},
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extractCommon: function(basePath, newString, oldString, diagonalPath) {
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var newLen = newString.length,
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oldLen = oldString.length,
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newPos = basePath.newPos,
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oldPos = newPos - diagonalPath,
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commonCount = 0;
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while (newPos + 1 < newLen && oldPos + 1 < oldLen && this.equals(newString[newPos + 1], oldString[oldPos + 1])) {
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newPos++;
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oldPos++;
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commonCount++;
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}
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if (commonCount) {
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basePath.components.push({count: commonCount});
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}
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basePath.newPos = newPos;
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return oldPos;
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},
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equals: function(left, right) {
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var reWhitespace = /\S/;
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return left === right || (this.ignoreWhitespace && !reWhitespace.test(left) && !reWhitespace.test(right));
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},
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tokenize: function(value) {
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return value.split('');
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}
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};
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var CharDiff = new Diff();
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var WordDiff = new Diff(true);
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var WordWithSpaceDiff = new Diff();
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WordDiff.tokenize = WordWithSpaceDiff.tokenize = function(value) {
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return removeEmpty(value.split(/(\s+|\b)/));
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};
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var CssDiff = new Diff(true);
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CssDiff.tokenize = function(value) {
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return removeEmpty(value.split(/([{}:;,]|\s+)/));
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};
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var LineDiff = new Diff();
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var TrimmedLineDiff = new Diff();
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TrimmedLineDiff.ignoreTrim = true;
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LineDiff.tokenize = TrimmedLineDiff.tokenize = function(value) {
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var retLines = [],
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lines = value.split(/^/m);
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for (var i = 0; i < lines.length; i++) {
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var line = lines[i],
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lastLine = lines[i - 1],
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lastLineLastChar = lastLine && lastLine[lastLine.length - 1];
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// Merge lines that may contain windows new lines
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if (line === '\n' && lastLineLastChar === '\r') {
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retLines[retLines.length - 1] = retLines[retLines.length - 1].slice(0, -1) + '\r\n';
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} else {
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if (this.ignoreTrim) {
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line = line.trim();
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// add a newline unless this is the last line.
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if (i < lines.length - 1) {
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line += '\n';
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}
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}
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retLines.push(line);
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}
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}
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return retLines;
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};
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var PatchDiff = new Diff();
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PatchDiff.tokenize = function(value) {
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var ret = [],
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linesAndNewlines = value.split(/(\n|\r\n)/);
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// Ignore the final empty token that occurs if the string ends with a new line
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if (!linesAndNewlines[linesAndNewlines.length - 1]) {
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linesAndNewlines.pop();
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}
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// Merge the content and line separators into single tokens
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for (var i = 0; i < linesAndNewlines.length; i++) {
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var line = linesAndNewlines[i];
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if (i % 2) {
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ret[ret.length - 1] += line;
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} else {
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ret.push(line);
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}
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}
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return ret;
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};
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var SentenceDiff = new Diff();
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SentenceDiff.tokenize = function(value) {
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return removeEmpty(value.split(/(\S.+?[.!?])(?=\s+|$)/));
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};
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var JsonDiff = new Diff();
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// Discriminate between two lines of pretty-printed, serialized JSON where one of them has a
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// dangling comma and the other doesn't. Turns out including the dangling comma yields the nicest output:
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JsonDiff.useLongestToken = true;
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JsonDiff.tokenize = LineDiff.tokenize;
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JsonDiff.equals = function(left, right) {
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return LineDiff.equals(left.replace(/,([\r\n])/g, '$1'), right.replace(/,([\r\n])/g, '$1'));
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};
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var JsDiff = {
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Diff: Diff,
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diffChars: function(oldStr, newStr, callback) { return CharDiff.diff(oldStr, newStr, callback); },
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diffWords: function(oldStr, newStr, callback) { return WordDiff.diff(oldStr, newStr, callback); },
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diffWordsWithSpace: function(oldStr, newStr, callback) { return WordWithSpaceDiff.diff(oldStr, newStr, callback); },
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diffLines: function(oldStr, newStr, callback) { return LineDiff.diff(oldStr, newStr, callback); },
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diffTrimmedLines: function(oldStr, newStr, callback) { return TrimmedLineDiff.diff(oldStr, newStr, callback); },
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diffSentences: function(oldStr, newStr, callback) { return SentenceDiff.diff(oldStr, newStr, callback); },
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diffCss: function(oldStr, newStr, callback) { return CssDiff.diff(oldStr, newStr, callback); },
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diffJson: function(oldObj, newObj, callback) {
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return JsonDiff.diff(
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typeof oldObj === 'string' ? oldObj : JSON.stringify(canonicalize(oldObj), undefined, ' '),
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typeof newObj === 'string' ? newObj : JSON.stringify(canonicalize(newObj), undefined, ' '),
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callback
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);
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},
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createTwoFilesPatch: function(oldFileName, newFileName, oldStr, newStr, oldHeader, newHeader) {
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var ret = [];
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if (oldFileName == newFileName) {
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ret.push('Index: ' + oldFileName);
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}
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ret.push('===================================================================');
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ret.push('--- ' + oldFileName + (typeof oldHeader === 'undefined' ? '' : '\t' + oldHeader));
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ret.push('+++ ' + newFileName + (typeof newHeader === 'undefined' ? '' : '\t' + newHeader));
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var diff = PatchDiff.diff(oldStr, newStr);
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diff.push({value: '', lines: []}); // Append an empty value to make cleanup easier
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// Formats a given set of lines for printing as context lines in a patch
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function contextLines(lines) {
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return map(lines, function(entry) { return ' ' + entry; });
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}
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// Outputs the no newline at end of file warning if needed
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function eofNL(curRange, i, current) {
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var last = diff[diff.length - 2],
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isLast = i === diff.length - 2,
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isLastOfType = i === diff.length - 3 && current.added !== last.added;
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// Figure out if this is the last line for the given file and missing NL
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if (!(/\n$/.test(current.value)) && (isLast || isLastOfType)) {
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curRange.push('\\ No newline at end of file');
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}
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}
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var oldRangeStart = 0, newRangeStart = 0, curRange = [],
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oldLine = 1, newLine = 1;
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for (var i = 0; i < diff.length; i++) {
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var current = diff[i],
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lines = current.lines || current.value.replace(/\n$/, '').split('\n');
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current.lines = lines;
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if (current.added || current.removed) {
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// If we have previous context, start with that
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if (!oldRangeStart) {
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var prev = diff[i - 1];
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oldRangeStart = oldLine;
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newRangeStart = newLine;
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if (prev) {
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curRange = contextLines(prev.lines.slice(-4));
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oldRangeStart -= curRange.length;
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newRangeStart -= curRange.length;
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}
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}
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// Output our changes
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curRange.push.apply(curRange, map(lines, function(entry) {
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return (current.added ? '+' : '-') + entry;
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}));
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eofNL(curRange, i, current);
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// Track the updated file position
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if (current.added) {
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newLine += lines.length;
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} else {
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oldLine += lines.length;
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}
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} else {
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// Identical context lines. Track line changes
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if (oldRangeStart) {
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// Close out any changes that have been output (or join overlapping)
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if (lines.length <= 8 && i < diff.length - 2) {
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// Overlapping
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curRange.push.apply(curRange, contextLines(lines));
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} else {
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// end the range and output
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var contextSize = Math.min(lines.length, 4);
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ret.push(
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'@@ -' + oldRangeStart + ',' + (oldLine - oldRangeStart + contextSize)
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+ ' +' + newRangeStart + ',' + (newLine - newRangeStart + contextSize)
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+ ' @@');
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ret.push.apply(ret, curRange);
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ret.push.apply(ret, contextLines(lines.slice(0, contextSize)));
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if (lines.length <= 4) {
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eofNL(ret, i, current);
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}
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oldRangeStart = 0;
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newRangeStart = 0;
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curRange = [];
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}
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}
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oldLine += lines.length;
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newLine += lines.length;
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}
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}
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return ret.join('\n') + '\n';
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},
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createPatch: function(fileName, oldStr, newStr, oldHeader, newHeader) {
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return JsDiff.createTwoFilesPatch(fileName, fileName, oldStr, newStr, oldHeader, newHeader);
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},
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applyPatch: function(oldStr, uniDiff) {
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var diffstr = uniDiff.split('\n'),
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hunks = [],
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i = 0,
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remEOFNL = false,
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addEOFNL = false;
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// Skip to the first change hunk
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while (i < diffstr.length && !(/^@@/.test(diffstr[i]))) {
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i++;
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}
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// Parse the unified diff
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for (; i < diffstr.length; i++) {
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|
if (diffstr[i][0] === '@') {
|
|
var chnukHeader = diffstr[i].split(/@@ -(\d+),(\d+) \+(\d+),(\d+) @@/);
|
|
hunks.unshift({
|
|
start: chnukHeader[3],
|
|
oldlength: +chnukHeader[2],
|
|
removed: [],
|
|
newlength: chnukHeader[4],
|
|
added: []
|
|
});
|
|
} else if (diffstr[i][0] === '+') {
|
|
hunks[0].added.push(diffstr[i].substr(1));
|
|
} else if (diffstr[i][0] === '-') {
|
|
hunks[0].removed.push(diffstr[i].substr(1));
|
|
} else if (diffstr[i][0] === ' ') {
|
|
hunks[0].added.push(diffstr[i].substr(1));
|
|
hunks[0].removed.push(diffstr[i].substr(1));
|
|
} else if (diffstr[i][0] === '\\') {
|
|
if (diffstr[i - 1][0] === '+') {
|
|
remEOFNL = true;
|
|
} else if (diffstr[i - 1][0] === '-') {
|
|
addEOFNL = true;
|
|
}
|
|
}
|
|
}
|
|
|
|
// Apply the diff to the input
|
|
var lines = oldStr.split('\n');
|
|
for (i = hunks.length - 1; i >= 0; i--) {
|
|
var hunk = hunks[i];
|
|
// Sanity check the input string. Bail if we don't match.
|
|
for (var j = 0; j < hunk.oldlength; j++) {
|
|
if (lines[hunk.start - 1 + j] !== hunk.removed[j]) {
|
|
return false;
|
|
}
|
|
}
|
|
Array.prototype.splice.apply(lines, [hunk.start - 1, hunk.oldlength].concat(hunk.added));
|
|
}
|
|
|
|
// Handle EOFNL insertion/removal
|
|
if (remEOFNL) {
|
|
while (!lines[lines.length - 1]) {
|
|
lines.pop();
|
|
}
|
|
} else if (addEOFNL) {
|
|
lines.push('');
|
|
}
|
|
return lines.join('\n');
|
|
},
|
|
|
|
convertChangesToXML: function(changes) {
|
|
var ret = [];
|
|
for (var i = 0; i < changes.length; i++) {
|
|
var change = changes[i];
|
|
if (change.added) {
|
|
ret.push('<ins>');
|
|
} else if (change.removed) {
|
|
ret.push('<del>');
|
|
}
|
|
|
|
ret.push(escapeHTML(change.value));
|
|
|
|
if (change.added) {
|
|
ret.push('</ins>');
|
|
} else if (change.removed) {
|
|
ret.push('</del>');
|
|
}
|
|
}
|
|
return ret.join('');
|
|
},
|
|
|
|
// See: http://code.google.com/p/google-diff-match-patch/wiki/API
|
|
convertChangesToDMP: function(changes) {
|
|
var ret = [],
|
|
change,
|
|
operation;
|
|
for (var i = 0; i < changes.length; i++) {
|
|
change = changes[i];
|
|
if (change.added) {
|
|
operation = 1;
|
|
} else if (change.removed) {
|
|
operation = -1;
|
|
} else {
|
|
operation = 0;
|
|
}
|
|
|
|
ret.push([operation, change.value]);
|
|
}
|
|
return ret;
|
|
},
|
|
|
|
canonicalize: canonicalize
|
|
};
|
|
|
|
/*istanbul ignore next */
|
|
/*global module */
|
|
if (typeof module !== 'undefined' && module.exports) {
|
|
module.exports = JsDiff;
|
|
} else if (typeof define === 'function' && define.amd) {
|
|
/*global define */
|
|
define([], function() { return JsDiff; });
|
|
} else if (typeof global.JsDiff === 'undefined') {
|
|
global.JsDiff = JsDiff;
|
|
}
|
|
}(this));
|