@zenfs/core/dist/vfs/shared.js

A filesystem, anywhere

// SPDX-License-Identifier: LGPL-3.0-or-later
// Utilities and shared data
import { Errno, Exception, UV, withErrno } from 'kerium';
import { alert, debug, err, info, notice, warn } from 'kerium/log';
import { InMemory } from '../backends/memory.js';
import { size_max } from '../constants.js';
import { contextOf } from '../internal/contexts.js';
import { credentialsAllowRoot } from '../internal/credentials.js';
import { withExceptionContext } from '../internal/error.js';
import { join, resolve } from '../path.js';
import { normalizePath } from '../utils.js';
/**
 * The map of mount points
 * @category Backends and Configuration
 * @internal
 */
export const mounts = new Map();
// Set a default root.
mount('/', InMemory.create({ label: 'root' }));
/**
 * Mounts the file system at `mountPoint`.
 * @category Backends and Configuration
 * @internal
 */
export function mount(mountPoint, fs) {
    if (mountPoint[0] != '/')
        mountPoint = '/' + mountPoint;
    mountPoint = resolve.call(this, mountPoint);
    if (mounts.has(mountPoint))
        throw err(withErrno('EINVAL', 'Mount point is already in use: ' + mountPoint));
    fs._mountPoint = mountPoint;
    mounts.set(mountPoint, fs);
    info(`Mounted ${fs.name} on ${mountPoint}`);
    debug(`${fs.name} attributes: ${[...fs.attributes].map(([k, v]) => (v !== undefined && v !== null ? k + '=' + v : k)).join(', ')}`);
}
/**
 * Unmounts the file system at `mountPoint`.
 * @category Backends and Configuration
 */
export function umount(mountPoint) {
    if (mountPoint[0] != '/')
        mountPoint = '/' + mountPoint;
    mountPoint = resolve.call(this, mountPoint);
    if (!mounts.has(mountPoint)) {
        warn(mountPoint + ' is already unmounted');
        return;
    }
    mounts.delete(mountPoint);
    notice('Unmounted ' + mountPoint);
}
/**
 * Gets the internal `FileSystem` for the path, then returns it along with the path relative to the FS' root
 * @internal @hidden
 */
export function resolveMount(path, ctx, extra) {
    const { root } = contextOf(ctx);
    const _exceptionContext = { path, ...extra };
    path = normalizePath(join(root, path), true);
    path = resolve.call(ctx, path);
    const sortedMounts = [...mounts].sort((a, b) => (a[0].length > b[0].length ? -1 : 1)); // descending order of the string length
    for (const [mountPoint, fs] of sortedMounts) {
        // We know path is normalized, so it would be a substring of the mount point.
        if (!_isParentOf(mountPoint, path))
            continue;
        path = path.slice(mountPoint.length > 1 ? mountPoint.length : 0); // Resolve the path relative to the mount point
        if (path === '')
            path = '/';
        const case_fold = fs.attributes.get('case_fold');
        if (case_fold === 'lower')
            path = path.toLowerCase();
        if (case_fold === 'upper')
            path = path.toUpperCase();
        return { fs: withExceptionContext(fs, _exceptionContext), path, mountPoint, root };
    }
    throw alert(new Exception(Errno.EIO, 'No file system for ' + path));
}
/**
 * @internal @hidden
 */
export function _statfs(fs, bigint) {
    const md = fs.usage();
    const bs = md.blockSize || 4096;
    return {
        type: (bigint ? BigInt : Number)(fs.type),
        bsize: (bigint ? BigInt : Number)(bs),
        ffree: (bigint ? BigInt : Number)(md.freeNodes || size_max),
        files: (bigint ? BigInt : Number)(md.totalNodes || size_max),
        bavail: (bigint ? BigInt : Number)(md.freeSpace / bs),
        bfree: (bigint ? BigInt : Number)(md.freeSpace / bs),
        blocks: (bigint ? BigInt : Number)(md.totalSpace / bs),
    };
}
/**
 * Change the root path
 * @category Backends and Configuration
 */
export function chroot(path) {
    const $ = contextOf(this);
    if (!credentialsAllowRoot($.credentials))
        throw withErrno('EPERM', 'Can not chroot() as non-root user');
    $.root ??= '/';
    const newRoot = join($.root, path);
    for (const handle of $.descriptors?.values() ?? []) {
        if (!handle.path.startsWith($.root))
            throw UV('EBUSY', 'chroot', handle.path);
        handle.path = handle.path.slice($.root.length);
    }
    if (newRoot.length > $.root.length)
        throw withErrno('EPERM', 'Can not chroot() outside of current root');
    $.root = newRoot;
}
/**
 * @internal @hidden
 */
function _isParentOf(parent, child) {
    if (parent === '/' || parent === child)
        return true;
    if (!parent.endsWith('/'))
        parent += '/';
    return child.startsWith(parent);
}