import { lstat, readlink, realpath } from 'fs/promises';
import { resolve, dirname } from 'path';
/**
* Track visited directories to prevent symlink loops
*/
export class SymlinkTracker {
private visitedInodes: Set<string> = new Set();
private visitedPaths: Set<string> = new Set();
/**
* Check if a path has been visited (potential loop)
* Returns true if safe to visit, false if loop detected
*/
async checkAndMark(filePath: string): Promise<boolean> {
try {
const stats = await lstat(filePath);
// Create unique identifier from device + inode
const inodeKey = `${stats.dev}:${stats.ino}`;
if (this.visitedInodes.has(inodeKey)) {
return false; // Loop detected
}
this.visitedInodes.add(inodeKey);
// Also track by resolved path for extra safety
if (stats.isSymbolicLink()) {
try {
const realPath = await realpath(filePath);
if (this.visitedPaths.has(realPath)) {
return false; // Loop detected
}
this.visitedPaths.add(realPath);
} catch {
// Can't resolve symlink, skip it
return false;
}
}
return true;
} catch {
// Can't stat file, skip it
return false;
}
}
/**
* Check if a path is a symlink
*/
async isSymlink(filePath: string): Promise<boolean> {
try {
const stats = await lstat(filePath);
return stats.isSymbolicLink();
} catch {
return false;
}
}
/**
* Resolve a symlink to its target
*/
async resolveSymlink(filePath: string): Promise<string | null> {
try {
const linkTarget = await readlink(filePath);
// Resolve relative symlinks
const absoluteTarget = resolve(dirname(filePath), linkTarget);
return absoluteTarget;
} catch {
return null;
}
}
/**
* Reset the tracker (for new search)
*/
reset(): void {
this.visitedInodes.clear();
this.visitedPaths.clear();
}
}
/**
* Create a new symlink tracker instance
*/
export function createSymlinkTracker(): SymlinkTracker {
return new SymlinkTracker();
}
