dagLink.js

'use strict'

const CID = require('cids')
const uint8ArrayFromString = require('uint8arrays/from-string')

/**
 * Link represents an IPFS Merkle DAG Link between Nodes.
 */
class DAGLink {
  /**
   * @param {string | undefined | null} name
   * @param {number} size
   * @param {CID | string | Uint8Array} cid
   */
  constructor (name, size, cid) {
    if (!cid) {
      throw new Error('A link requires a cid to point to')
    }

    // assert(size, 'A link requires a size')
    //  note - links should include size, but this assert is disabled
    //  for now to maintain consistency with go-ipfs pinset
    this.Name = name || ''
    this.Tsize = size
    this.Hash = new CID(cid)

    Object.defineProperties(this, {
      _nameBuf: { value: null, writable: true, enumerable: false }
    })
  }

  toString () {
    return `DAGLink <${this.Hash.toBaseEncodedString()} - name: "${this.Name}", size: ${this.Tsize}>`
  }

  toJSON () {
    if (!this._json) {
      this._json = Object.freeze({
        name: this.Name,
        size: this.Tsize,
        cid: this.Hash.toBaseEncodedString()
      })
    }

    return Object.assign({}, this._json)
  }

  // Memoize the Uint8Array representation of name
  // We need this to sort the links, otherwise
  // we will reallocate new Uint8Arrays every time
  get nameAsBuffer () {
    if (this._nameBuf != null) {
      return this._nameBuf
    }

    this._nameBuf = uint8ArrayFromString(this.Name)
    return this._nameBuf
  }
}

module.exports = DAGLink