@ezdevlol/memfs/lib/node.js

In-memory file-system with Node's fs API.

import process from './process';
import { Buffer, bufferAllocUnsafe, bufferFrom } from './internal/buffer';
import { constants } from './constants';
import { EventEmitter } from 'events';
import Stats from './Stats';
const { S_IFMT, S_IFDIR, S_IFREG, S_IFLNK, S_IFCHR, O_APPEND } = constants;
const getuid = () => process.getuid?.() ?? 0;
const getgid = () => process.getgid?.() ?? 0;
export const SEP = '/';
/**
 * Node in a file system (like i-node, v-node).
 */
export class Node extends EventEmitter {
    // i-node number.
    ino;
    // User ID and group ID.
    _uid = getuid();
    _gid = getgid();
    _atime = new Date();
    _mtime = new Date();
    _ctime = new Date();
    // data: string = '';
    buf;
    rdev = 0;
    mode; // S_IFDIR, S_IFREG, etc..
    // Number of hard links pointing at this Node.
    _nlink = 1;
    // Path to another node, if this is a symlink.
    symlink;
    constructor(ino, mode = 0o666) {
        super();
        this.mode = mode;
        this.ino = ino;
    }
    set ctime(ctime) {
        this._ctime = ctime;
    }
    get ctime() {
        return this._ctime;
    }
    set uid(uid) {
        this._uid = uid;
        this.ctime = new Date();
    }
    get uid() {
        return this._uid;
    }
    set gid(gid) {
        this._gid = gid;
        this.ctime = new Date();
    }
    get gid() {
        return this._gid;
    }
    set atime(atime) {
        this._atime = atime;
        this.ctime = new Date();
    }
    get atime() {
        return this._atime;
    }
    set mtime(mtime) {
        this._mtime = mtime;
        this.ctime = new Date();
    }
    get mtime() {
        return this._mtime;
    }
    get perm() {
        return this.mode & ~S_IFMT;
    }
    set perm(perm) {
        this.mode = (this.mode & S_IFMT) | (perm & ~S_IFMT);
        this.ctime = new Date();
    }
    set nlink(nlink) {
        this._nlink = nlink;
        this.ctime = new Date();
    }
    get nlink() {
        return this._nlink;
    }
    getString(encoding = 'utf8') {
        this.atime = new Date();
        return this.getBuffer().toString(encoding);
    }
    setString(str) {
        // this.setBuffer(bufferFrom(str, 'utf8'));
        this.buf = bufferFrom(str, 'utf8');
        this.touch();
    }
    getBuffer() {
        this.atime = new Date();
        if (!this.buf)
            this.setBuffer(bufferAllocUnsafe(0));
        return bufferFrom(this.buf); // Return a copy.
    }
    setBuffer(buf) {
        this.buf = bufferFrom(buf); // Creates a copy of data.
        this.touch();
    }
    getSize() {
        return this.buf ? this.buf.length : 0;
    }
    setModeProperty(property) {
        this.mode = property;
    }
    isFile() {
        return (this.mode & S_IFMT) === S_IFREG;
    }
    isDirectory() {
        return (this.mode & S_IFMT) === S_IFDIR;
    }
    isSymlink() {
        // return !!this.symlink;
        return (this.mode & S_IFMT) === S_IFLNK;
    }
    isCharacterDevice() {
        return (this.mode & S_IFMT) === S_IFCHR;
    }
    makeSymlink(symlink) {
        this.mode = S_IFLNK | 0o666;
        this.symlink = symlink;
    }
    write(buf, off = 0, len = buf.length, pos = 0) {
        if (!this.buf)
            this.buf = bufferAllocUnsafe(0);
        if (pos + len > this.buf.length) {
            const newBuf = bufferAllocUnsafe(pos + len);
            this.buf.copy(newBuf, 0, 0, this.buf.length);
            this.buf = newBuf;
        }
        buf.copy(this.buf, pos, off, off + len);
        this.touch();
        return len;
    }
    // Returns the number of bytes read.
    read(buf, off = 0, len = buf.byteLength, pos = 0) {
        this.atime = new Date();
        if (!this.buf)
            this.buf = bufferAllocUnsafe(0);
        if (pos >= this.buf.length)
            return 0;
        let actualLen = len;
        if (actualLen > buf.byteLength) {
            actualLen = buf.byteLength;
        }
        if (actualLen + pos > this.buf.length) {
            actualLen = this.buf.length - pos;
        }
        const buf2 = buf instanceof Buffer ? buf : Buffer.from(buf.buffer);
        this.buf.copy(buf2, off, pos, pos + actualLen);
        return actualLen;
    }
    truncate(len = 0) {
        if (!len)
            this.buf = bufferAllocUnsafe(0);
        else {
            if (!this.buf)
                this.buf = bufferAllocUnsafe(0);
            if (len <= this.buf.length) {
                this.buf = this.buf.slice(0, len);
            }
            else {
                const buf = bufferAllocUnsafe(len);
                this.buf.copy(buf);
                buf.fill(0, this.buf.length);
                this.buf = buf;
            }
        }
        this.touch();
    }
    chmod(perm) {
        this.mode = (this.mode & S_IFMT) | (perm & ~S_IFMT);
        this.touch();
    }
    chown(uid, gid) {
        this.uid = uid;
        this.gid = gid;
        this.touch();
    }
    touch() {
        this.mtime = new Date();
        this.emit('change', this);
    }
    canRead(uid = getuid(), gid = getgid()) {
        if (this.perm & 4 /* S.IROTH */) {
            return true;
        }
        if (gid === this.gid) {
            if (this.perm & 32 /* S.IRGRP */) {
                return true;
            }
        }
        if (uid === this.uid) {
            if (this.perm & 256 /* S.IRUSR */) {
                return true;
            }
        }
        return false;
    }
    canWrite(uid = getuid(), gid = getgid()) {
        if (this.perm & 2 /* S.IWOTH */) {
            return true;
        }
        if (gid === this.gid) {
            if (this.perm & 16 /* S.IWGRP */) {
                return true;
            }
        }
        if (uid === this.uid) {
            if (this.perm & 128 /* S.IWUSR */) {
                return true;
            }
        }
        return false;
    }
    canExecute(uid = getuid(), gid = getgid()) {
        if (this.perm & 1 /* S.IXOTH */) {
            return true;
        }
        if (gid === this.gid) {
            if (this.perm & 8 /* S.IXGRP */) {
                return true;
            }
        }
        if (uid === this.uid) {
            if (this.perm & 64 /* S.IXUSR */) {
                return true;
            }
        }
        return false;
    }
    del() {
        this.emit('delete', this);
    }
    toJSON() {
        return {
            ino: this.ino,
            uid: this.uid,
            gid: this.gid,
            atime: this.atime.getTime(),
            mtime: this.mtime.getTime(),
            ctime: this.ctime.getTime(),
            perm: this.perm,
            mode: this.mode,
            nlink: this.nlink,
            symlink: this.symlink,
            data: this.getString(),
        };
    }
}
/**
 * Represents a hard link that points to an i-node `node`.
 */
export class Link extends EventEmitter {
    vol;
    parent;
    children = new Map();
    // Path to this node as Array: ['usr', 'bin', 'node'].
    _steps = [];
    // "i-node" of this hard link.
    node;
    // "i-node" number of the node.
    ino = 0;
    // Number of children.
    length = 0;
    name;
    get steps() {
        return this._steps;
    }
    // Recursively sync children steps, e.g. in case of dir rename
    set steps(val) {
        this._steps = val;
        for (const [child, link] of this.children.entries()) {
            if (child === '.' || child === '..') {
                continue;
            }
            link?.syncSteps();
        }
    }
    constructor(vol, parent, name) {
        super();
        this.vol = vol;
        this.parent = parent;
        this.name = name;
        this.syncSteps();
    }
    setNode(node) {
        this.node = node;
        this.ino = node.ino;
    }
    getNode() {
        return this.node;
    }
    createChild(name, node = this.vol.createNode(S_IFREG | 0o666)) {
        const link = new Link(this.vol, this, name);
        link.setNode(node);
        if (node.isDirectory()) {
            link.children.set('.', link);
            link.getNode().nlink++;
        }
        this.setChild(name, link);
        return link;
    }
    setChild(name, link = new Link(this.vol, this, name)) {
        this.children.set(name, link);
        link.parent = this;
        this.length++;
        const node = link.getNode();
        if (node.isDirectory()) {
            link.children.set('..', this);
            this.getNode().nlink++;
        }
        this.getNode().mtime = new Date();
        this.emit('child:add', link, this);
        return link;
    }
    deleteChild(link) {
        const node = link.getNode();
        if (node.isDirectory()) {
            link.children.delete('..');
            this.getNode().nlink--;
        }
        this.children.delete(link.getName());
        this.length--;
        this.getNode().mtime = new Date();
        this.emit('child:delete', link, this);
    }
    getChild(name) {
        this.getNode().mtime = new Date();
        return this.children.get(name);
    }
    getPath() {
        return this.steps.join(SEP);
    }
    getParentPath() {
        return this.steps.slice(0, -1).join(SEP);
    }
    getName() {
        return this.steps[this.steps.length - 1];
    }
    // del() {
    //     const parent = this.parent;
    //     if(parent) {
    //         parent.deleteChild(link);
    //     }
    //     this.parent = null;
    //     this.vol = null;
    // }
    toJSON() {
        return {
            steps: this.steps,
            ino: this.ino,
            children: Array.from(this.children.keys()),
        };
    }
    syncSteps() {
        this.steps = this.parent ? this.parent.steps.concat([this.name]) : [this.name];
    }
}
/**
 * Represents an open file (file descriptor) that points to a `Link` (Hard-link) and a `Node`.
 */
export class File {
    fd;
    /**
     * Hard link that this file opened.
     * @type {any}
     */
    link;
    /**
     * Reference to a `Node`.
     * @type {Node}
     */
    node;
    /**
     * A cursor/offset position in a file, where data will be written on write.
     * User can "seek" this position.
     */
    position;
    // Flags used when opening the file.
    flags;
    /**
     * Open a Link-Node pair. `node` is provided separately as that might be a different node
     * rather the one `link` points to, because it might be a symlink.
     * @param link
     * @param node
     * @param flags
     * @param fd
     */
    constructor(link, node, flags, fd) {
        this.link = link;
        this.node = node;
        this.flags = flags;
        this.fd = fd;
        this.position = 0;
        if (this.flags & O_APPEND)
            this.position = this.getSize();
    }
    getString(encoding = 'utf8') {
        return this.node.getString();
    }
    setString(str) {
        this.node.setString(str);
    }
    getBuffer() {
        return this.node.getBuffer();
    }
    setBuffer(buf) {
        this.node.setBuffer(buf);
    }
    getSize() {
        return this.node.getSize();
    }
    truncate(len) {
        this.node.truncate(len);
    }
    seekTo(position) {
        this.position = position;
    }
    stats() {
        return Stats.build(this.node);
    }
    write(buf, offset = 0, length = buf.length, position) {
        if (typeof position !== 'number')
            position = this.position;
        const bytes = this.node.write(buf, offset, length, position);
        this.position = position + bytes;
        return bytes;
    }
    read(buf, offset = 0, length = buf.byteLength, position) {
        if (typeof position !== 'number')
            position = this.position;
        const bytes = this.node.read(buf, offset, length, position);
        this.position = position + bytes;
        return bytes;
    }
    chmod(perm) {
        this.node.chmod(perm);
    }
    chown(uid, gid) {
        this.node.chown(uid, gid);
    }
}