bare-operating-system/packages/bare-os-seeder/kernel/bin/xattr

/* BARE_OS_BIN_API 1.0.0 — bump when staged /bin script semantics change (see developer guide). */
/** Shared helpers for drive-resident /bin scripts (prepended before each command). */
function bareStdin(ctx) {
  return typeof ctx.shellStdin === 'string' ? ctx.shellStdin : ''
}

/** @param {number} mode @param {'file' | 'directory' | 'symlink'} type */
function bareFormatModeString(mode, type) {
  const typeChar = type === 'directory' ? 'd' : type === 'symlink' ? 'l' : '-'
  const perm = mode & 0o777
  const r = (bit) => (perm & bit ? 'r' : '-')
  const w = (bit) => (perm & bit ? 'w' : '-')
  const x = (bit) => (perm & bit ? 'x' : '-')
  return (
    typeChar +
    r(0o400) +
    w(0o200) +
    x(0o100) +
    r(0o040) +
    w(0o020) +
    x(0o010) +
    r(0o004) +
    w(0o002) +
    x(0o001)
  )
}

/** @param {number} mtimeMs @param {number} [nowMs] */
function bareFormatLsMtime(mtimeMs, nowMs) {
  const now = nowMs != null ? nowMs : Date.now()
  const d = new Date(mtimeMs)
  const months = [
    'Jan',
    'Feb',
    'Mar',
    'Apr',
    'May',
    'Jun',
    'Jul',
    'Aug',
    'Sep',
    'Oct',
    'Nov',
    'Dec'
  ]
  const mon = months[d.getMonth()]
  const day = String(d.getDate()).padStart(2, ' ')
  const sixMo = 180 * 24 * 3600 * 1000
  if (Math.abs(now - mtimeMs) > sixMo) {
    const yr = String(d.getFullYear()).padStart(4, ' ')
    return mon + ' ' + day + '  ' + yr
  }
  const hh = String(d.getHours()).padStart(2, '0')
  const mm = String(d.getMinutes()).padStart(2, '0')
  return mon + ' ' + day + ' ' + hh + ':' + mm
}

/** @param {number} size */
function barePosixBlocks(size) {
  return Math.ceil(Number(size) / 512) || 0
}

/**
 * Raw stdout for NUL/binary when **`process.stdout.write`** is missing.
 * If **`ctx.bareOsBinWrite(Uint8Array|string)`** is set (tests / host), use it.
 * @param {Record<string, unknown>} ctx
 * @param {string | Uint8Array} chunk
 * @returns {boolean}
 */
function bareOsEmitRaw(ctx, chunk) {
  if (typeof ctx.bareOsBinWrite === 'function') {
    const b4 = ctx.b4a
    const u8 =
      typeof chunk === 'string'
        ? b4 && typeof b4.from === 'function'
          ? b4.from(chunk)
          : new TextEncoder().encode(chunk)
        : chunk
    ctx.bareOsBinWrite(u8 instanceof Uint8Array ? u8 : new Uint8Array(u8))
    return true
  }
  const w = globalThis.process?.stdout?.write
  if (typeof w === 'function') {
    w.call(globalThis.process.stdout, chunk)
    return true
  }
  return false
}

/**
 * xattr — extended attributes via sidecar JSON (PATH.bare_xattr.json).
 * Values are stored base64-encoded UTF-8 strings for JSON safety.
 */

/**
 * @param {string} val
 */
function xattrB64Encode(val) {
  const s = String(val)
  if (typeof globalThis.Buffer !== 'undefined') {
    return globalThis.Buffer.from(s, 'utf8').toString('base64')
  }
  const u8 = new TextEncoder().encode(s)
  let bin = ''
  for (let i = 0; i < u8.length; i++) bin += String.fromCharCode(u8[i])
  if (typeof globalThis.btoa === 'function') return globalThis.btoa(bin)
  throw new Error('xattr: base64 encode unavailable')
}

/**
 * @param {string} b64
 */
function xattrB64Decode(b64) {
  const t = String(b64).replace(/\s+/g, '')
  if (typeof globalThis.Buffer !== 'undefined') {
    return globalThis.Buffer.from(t, 'base64').toString('utf8')
  }
  if (typeof globalThis.atob === 'function') {
    const bin = globalThis.atob(t)
    let out = ''
    for (let i = 0; i < bin.length; i++) out += bin[i]
    return out
  }
  throw new Error('xattr: base64 decode unavailable')
}

/**
 * @param {Record<string, unknown>} ctx
 * @param {string} path
 */
async function readXattrMap(ctx, path) {
  const side = path + '.bare_xattr.json'
  const raw = await ctx.vfs.readFile(side)
  if (!raw || !raw.byteLength) return {}
  try {
    const o = JSON.parse(ctx.b4a.toString(raw))
    return o && typeof o === 'object' && !Array.isArray(o) ? o : {}
  } catch {
    return {}
  }
}

/**
 * @param {Record<string, unknown>} ctx
 * @param {string} path
 * @param {Record<string, string>} obj
 */
async function writeXattrMap(ctx, path, obj) {
  const side = path + '.bare_xattr.json'
  const text = JSON.stringify(obj) + '\n'
  await ctx.vfs.writeFile(side, ctx.b4a.from(text))
}

async function run(ctx, argv) {
  let list = false
  /** @type {string | null} */
  let delName = null
  /** @type {{ name: string, val: string } | null} */
  let writePair = null
  /** @type {string | null} */
  let printName = null
  /** @type {string[]} */
  const rest = []
  for (let i = 1; i < argv.length; i++) {
    const a = argv[i]
    if (a === '-l' || a === '--list') {
      list = true
      continue
    }
    if (a === '-w' || a === '--write') {
      const name = argv[i + 1]
      const val = argv[i + 2]
      if (!name || val == null) {
        ctx.console.error('xattr: -w requires NAME VALUE')
        ctx.exitCode = 1
        return
      }
      writePair = { name, val }
      i += 2
      continue
    }
    if (a === '-p' || a === '--print') {
      const name = argv[i + 1]
      if (!name) {
        ctx.console.error('xattr: -p requires NAME')
        ctx.exitCode = 1
        return
      }
      printName = name
      i++
      continue
    }
    if (a === '-d' || a === '--delete') {
      const name = argv[i + 1]
      if (!name) {
        ctx.console.error('xattr: -d requires NAME')
        ctx.exitCode = 1
        return
      }
      delName = name
      i++
      continue
    }
    if (a === '--help' || a === '-h') {
      ctx.console.log('usage: xattr [-l] [-p NAME] [-w NAME VALUE] [-d NAME] PATH')
      return
    }
    if (a.startsWith('-')) {
      ctx.console.error('xattr: unsupported option ' + a)
      ctx.exitCode = 1
      return
    }
    rest.push(a)
  }
  if (rest.length !== 1) {
    ctx.console.error('usage: xattr [-l] [-p NAME] [-w NAME VALUE] [-d NAME] PATH')
    ctx.exitCode = 1
    return
  }
  const path = rest[0]
  try {
    const st = await ctx.vfs.stat(path)
    if (!st) {
      ctx.console.error('xattr: ' + path + ': No such file')
      ctx.exitCode = 1
      return
    }
    const obj = /** @type {Record<string, string>} */ (await readXattrMap(ctx, path))
    if (delName) {
      delete obj[delName]
      await writeXattrMap(ctx, path, obj)
      return
    }
    if (writePair) {
      obj[writePair.name] = xattrB64Encode(writePair.val)
      await writeXattrMap(ctx, path, obj)
      ctx.console.log(writePair.name)
      return
    }
    if (printName) {
      if (!Object.prototype.hasOwnProperty.call(obj, printName)) {
        ctx.console.error('xattr: ' + printName + ': No such xattr')
        ctx.exitCode = 1
        return
      }
      ctx.console.log(xattrB64Decode(obj[printName]))
      return
    }
    const keys = Object.keys(obj).sort()
    for (const k of keys) {
      if (list) {
        ctx.console.log(k + ': ' + xattrB64Decode(obj[k]))
      } else {
        ctx.console.log(k)
      }
    }
  } catch (e) {
    ctx.console.error('xattr: ' + (e && e.message ? e.message : String(e)))
    ctx.exitCode = 1
  }
}