| 1 | let createHasher = require('multihasher')
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| 2 |
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| 3 | class InMemoryContentAddressableStorage {
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| 4 | constructor (hasher = createHasher('sha256')) {
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| 5 | this._store = new Map()
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| 6 | this._hasher = hasher
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| 7 | }
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| 8 |
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| 9 | async get (hash, cb) {
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| 10 | let buff = this._store.get(hash)
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| 11 | if (typeof buff === 'undefined') throw new Error('Not found.')
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| 12 | return buff
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| 13 | }
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| 14 |
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| 15 | async hash (value, ...args) {
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| 16 | if (!Buffer.isBuffer(value)) throw new Error('Invalid type.')
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| 17 | return this._hasher(value, ...args)
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| 18 | }
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| 19 |
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| 20 | async set (value, ...args) {
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| 21 | if (!Buffer.isBuffer(value)) throw new Error('Invalid type.')
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| 22 | let hash = await this._hasher(value, ...args)
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| 23 | this._store.set(hash, value)
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| 24 | return hash
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| 25 | }
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| 26 |
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| 27 | async missing (hashes) {
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| 28 | let have = new Set(this._store.keys())
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| 29 | let diff = new Set(hashes.filter(h => !have.has(h)))
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| 30 | return Array.from(diff)
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| 31 | }
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| 32 | }
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| 33 |
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| 34 | module.exports = hasher => new InMemoryContentAddressableStorage(hasher)
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