2024-10-23 16:04:37 -07:00

128 lines
3.7 KiB
TypeScript

/**
* Copyright (c) Microsoft Corporation.
*
* 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.
*/
import { diffMatchPatch } from '../utilsBundle';
type Hunk = {
lines: string[];
startNew: number;
startOld: number;
contextBefore: number;
contextAfter: number;
};
export function generateUnifiedDiff(text1: string, text2: string, relativeName: string = 'file'): string {
const { diff_match_patch, DIFF_EQUAL, DIFF_DELETE, DIFF_INSERT } = diffMatchPatch;
const dmp = new diff_match_patch();
const a = text1.replace(/\r\n/g, '\n');
const b = text2.replace(/\r\n/g, '\n');
const { chars1, chars2, lineArray } = dmp.diff_linesToChars_(a, b);
const diffs = dmp.diff_main(chars1, chars2, false);
dmp.diff_charsToLines_(diffs, lineArray);
const contextSize = 3;
const hunks: Hunk[] = [];
let lineOld = 1;
let lineNew = 1;
let hunk: Hunk | null = null;
let contextBuffer: string[] = [];
for (const diff of diffs) {
const op = diff[0];
const data = diff[1];
const lines = data.split('\n');
// Remove the last empty line if data ends with '\n'
if (lines[lines.length - 1] === '')
lines.pop();
for (const line of lines) {
if (op === DIFF_EQUAL) {
if (hunk) {
hunk.lines.push(' ' + line);
hunk.contextAfter++;
if (hunk.contextAfter >= contextSize) {
// Close the hunk
hunks.push(hunk);
hunk = null;
contextBuffer = [];
}
} else {
contextBuffer.push(' ' + line);
if (contextBuffer.length > contextSize)
contextBuffer.shift();
}
lineOld++;
lineNew++;
} else {
if (!hunk) {
// Start a new hunk
const hunkStartOld = lineOld - contextBuffer.length;
const hunkStartNew = lineNew - contextBuffer.length;
hunk = {
startOld: hunkStartOld,
startNew: hunkStartNew,
lines: [...contextBuffer],
contextBefore: contextBuffer.length,
contextAfter: 0,
};
}
hunk.contextAfter = 0;
if (op === DIFF_DELETE) {
hunk.lines.push('-' + line);
lineOld++;
} else if (op === DIFF_INSERT) {
hunk.lines.push('+' + line);
lineNew++;
}
}
}
}
if (hunk)
hunks.push(hunk);
// Build the unified diff text
let diffText = `--- a/${relativeName}\n+++ b/${relativeName}\n`;
for (const hunk of hunks) {
// Calculate hunk ranges
const oldRangeStart = hunk.startOld;
const newRangeStart = hunk.startNew;
let oldRangeLines = 0;
let newRangeLines = 0;
for (const line of hunk.lines) {
if (line.startsWith('-') || line.startsWith(' '))
oldRangeLines++;
if (line.startsWith('+') || line.startsWith(' '))
newRangeLines++;
}
// Adjust starting line numbers when range is empty
const oldStartLine = oldRangeLines === 0 ? oldRangeStart - 1 : oldRangeStart;
const newStartLine = newRangeLines === 0 ? newRangeStart - 1 : newRangeStart;
diffText += `@@ -${oldStartLine},${oldRangeLines} +${newStartLine},${newRangeLines} @@\n`;
diffText += hunk.lines.map(line => line + '\n').join('');
}
return diffText;
}