Maybe use the same Blockstore interface as @ipld/car

[olizilla]

I was noodling around and wondered if I could re-use the dagula decode'n'walk logic on a CAR file. It was a success, but made slightly rougher by the different expectations of what a Block{store|Reader}'s get method signature should be.

dagular Blockstore
return a promise of the bytes or throw

get: (cid: CID, options?: { signal?: AbortSignal }) => Promise<Uint8Array>

source

@ipld/car BlockReader
return a promise of {cid: CID, bytes: Uint8Array} or undefined

get(key: CID): Promise<Block | undefined>

source

[olizilla]

for fun, here is dagular using a CAR instead of the bit swap. Might be rad to be able to just pass in a CarReader and have it just work.

import { Dagula } from 'dagula'
import { CarIndexedReader } from '@ipld/car/indexed-reader'

export async function carWalk (input) {
  const carReader = await CarIndexedReader.fromFile(input)
  const blockstore = new CarBlockStore(carReader)
  const roots = await carReader.getRoots()
  const dagula = new Dagula(blockstore)
  try {
    for await (const block of dagula.get(roots[0])) {
      console.log(block.cid.toString())
    }
  } finally {
    await carReader.close()
  }
}

class CarBlockStore {
  #carReader
  constructor (carReader) {
    this.#carReader = carReader
  }
  async get (cid) {
    const block = await this.#carReader.get(cid)
    if (!block) {
      throw new Error('no such block')
    }
    return block.bytes
  }
}

console.log(`dang ${process.argv[2]}`)
carWalk(process.argv[2])

[alanshaw]

👍 yes this is a good idea!