ipfs-repo/src/version.js

IPFS Repo implementation

import { Key } from 'interface-datastore/key'
import debug from 'debug'
import { toString as uint8ArrayToString } from 'uint8arrays/to-string'
import { fromString as uint8ArrayFromString } from 'uint8arrays/from-string'
import { getWithFallback, hasWithFallback } from './utils/level.js'

const log = debug('ipfs:repo:version')
const versionKey = new Key('version')

/**
 *
 * @param {import('interface-datastore').Datastore} store
 */
export function version (store) {
  return {
    /**
     * Check if a version file exists.
     *
     */
    async exists () { // eslint-disable-line require-await
      // level-js@5.x cannot read keys from level-js@4.x dbs so fall back to
      // using IndexedDB API with string keys - only necessary until we do
      // the migratiion to v10 or above
      return hasWithFallback(versionKey, store.has.bind(store), store)
    },
    /**
     * Get the current version.
     *
     * @returns {Promise<number>}
     */
    async get () {
      // level-js@5.x cannot read keys from level-js@4.x dbs so fall back to
      // using IndexedDB API with string keys - only necessary until we do
      // the migratiion to v10 or above
      const buf = await getWithFallback(versionKey, store.get.bind(store), store.has.bind(store), store)
      return parseInt(uint8ArrayToString(buf), 10)
    },
    /**
     * Set the version of the repo, writing it to the underlying store.
     *
     * @param {number} version
     * @returns {Promise<void>}
     */
    set (version) {
      return store.put(versionKey, uint8ArrayFromString(String(version)))
    },
    /**
     * Check the current version, and returns true if versions matches
     *
     * @param {number} expected
     */
    async check (expected) {
      const version = await this.get()
      log('comparing version: %s and %s', version, expected)
      // Version 6 and 7 are the same
      // TODO: Clean up the compatibility logic. Repo feature detection would be ideal, or a better version schema
      const compatibleVersion = (version === 6 && expected === 7) || (expected === 6 && version === 7)

      return version === expected || compatibleVersion
    }
  }
}