vzcode/dist/utils/fileDiff.js

Multiplayer code editor system

import { createTwoFilesPatch } from 'diff';
// Special marker to indicate a file deletion
export const FILE_DELETION_MARKER = '__FILE_DELETED__';
/**
 * Check if a diff string represents a file deletion
 */
export function isFileDeletion(diffString) {
    return diffString.startsWith(FILE_DELETION_MARKER);
}
/**
 * Extract file name from a deletion marker
 */
export function getDeletedFileName(diffString) {
    if (!isFileDeletion(diffString)) {
        return '';
    }
    return diffString.substring(FILE_DELETION_MARKER.length + 1);
}
/**
 * Generate a unified diff for a single file using the diff library
 */
export function generateFileUnifiedDiff(fileId, fileName, beforeContent, afterContent) {
    // Only generate diff if there are actual changes
    if (beforeContent === afterContent) {
        return '';
    }
    // Handle file deletion case - when file existed before but is now empty/deleted
    if (beforeContent && !afterContent) {
        return `${FILE_DELETION_MARKER}:${fileName}`;
    }
    // Use the diff library's createTwoFilesPatch function to generate unified diff
    const unifiedDiff = createTwoFilesPatch(fileName, fileName, beforeContent, afterContent, '', '', { context: 3 });
    return unifiedDiff;
}
/**
 * Generate unified diffs for multiple files
 */
export function generateFilesUnifiedDiff(beforeFiles, afterFiles) {
    const result = {};
    const allFileIds = new Set([
        ...Object.keys(beforeFiles),
        ...Object.keys(afterFiles),
    ]);
    for (const fileId of allFileIds) {
        const beforeFile = beforeFiles[fileId];
        const afterFile = afterFiles[fileId];
        const beforeContent = beforeFile?.text || '';
        const afterContent = afterFile?.text || '';
        const fileName = afterFile?.name || beforeFile?.name || fileId;
        const unifiedDiff = generateFileUnifiedDiff(fileId, fileName, beforeContent, afterContent);
        // Only include files that have changes
        if (unifiedDiff) {
            result[fileId] = unifiedDiff;
        }
    }
    return result;
}
/**
 * Create a snapshot of current files for diff comparison
 */
export function createFilesSnapshot(files) {
    return JSON.parse(JSON.stringify(files));
}
/**
 * Parse unified diff to extract basic statistics
 */
export function parseUnifiedDiffStats(unifiedDiff) {
    const lines = unifiedDiff.split('\n');
    let additions = 0;
    let deletions = 0;
    for (const line of lines) {
        if (line.startsWith('+') && !line.startsWith('+++')) {
            additions++;
        }
        else if (line.startsWith('-') &&
            !line.startsWith('---')) {
            deletions++;
        }
    }
    return { additions, deletions };
}
/**
 * Combine multiple unified diffs into a single diff string
 * Note: File deletion markers are excluded from combination
 */
export function combineUnifiedDiffs(unifiedDiffs) {
    return Object.values(unifiedDiffs)
        .filter((diff) => !isFileDeletion(diff))
        .join('\n');
}