nwaku/waku/waku_keystore/utils.nim

when (NimMajor, NimMinor) < (1, 4):
  {.push raises: [Defect].}
else:
  {.push raises: [].}

import
  json,
  std/[os, sequtils]

import
  ./keyfile,
  ./protocol_types

# Checks if a JsonNode has all keys contained in "keys"
proc hasKeys*(data: JsonNode, keys: openArray[string]): bool =
  return all(keys, proc (key: string): bool = return data.hasKey(key))

# Safely saves a Keystore's JsonNode to disk.
# If exists, the destination file is renamed with extension .bkp; the file is written at its destination and the .bkp file is removed if write is successful, otherwise is restored
proc save*(json: JsonNode, path: string, separator: string): KeystoreResult[void] =
  # We first backup the current keystore
  if fileExists(path):
    try:
      moveFile(path, path & ".bkp")
    except:  # TODO: Fix "BareExcept" warning
      return err(AppKeystoreError(kind: KeystoreOsError,
                                  msg: "could not backup keystore: " & getCurrentExceptionMsg()))

  # We save the updated json
  var f: File
  if not f.open(path, fmAppend):
    return err(AppKeystoreError(kind: KeystoreOsError,
                                msg: getCurrentExceptionMsg()))
  try:
    # To avoid other users/attackers to be able to read keyfiles, we make the file readable/writable only by the running user
    setFilePermissions(path, {fpUserWrite, fpUserRead})
    f.write($json)
    # We store a keyfile per line
    f.write(separator)
  except CatchableError:
    # We got some KeystoreOsError writing to disk. We attempt to restore the previous keystore backup
    if fileExists(path & ".bkp"):
      try:
        f.close()
        removeFile(path)
        moveFile(path & ".bkp", path)
      except:  # TODO: Fix "BareExcept" warning
        # Unlucky, we just fail
        return err(AppKeystoreError(kind: KeystoreOsError,
                                    msg: "could not restore keystore backup: " & getCurrentExceptionMsg()))
    return err(AppKeystoreError(kind: KeystoreOsError,
                                msg: "could not write keystore: " & getCurrentExceptionMsg()))
  finally:
    f.close()

  # The write went fine, so we can remove the backup keystore
  if fileExists(path & ".bkp"):
    try:
      removeFile(path & ".bkp")
    except CatchableError:
      return err(AppKeystoreError(kind: KeystoreOsError,
                                  msg: "could not remove keystore backup: " & getCurrentExceptionMsg()))

  return ok()