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'use strict'
const events = require('events')
const contentPath = require('./path')
const fs = require('fs/promises')
const moveFile = require('../util/move-file')
const Minipass = require('minipass')
const Pipeline = require('minipass-pipeline')
const Flush = require('minipass-flush')
const path = require('path')
const ssri = require('ssri')
const uniqueFilename = require('unique-filename')
const fsm = require('fs-minipass')
module.exports = write
async function write (cache, data, opts = {}) {
const { algorithms, size, integrity } = opts
if (algorithms && algorithms.length > 1) {
throw new Error('opts.algorithms only supports a single algorithm for now')
}
if (typeof size === 'number' && data.length !== size) {
throw sizeError(size, data.length)
}
const sri = ssri.fromData(data, algorithms ? { algorithms } : {})
if (integrity && !ssri.checkData(data, integrity, opts)) {
throw checksumError(integrity, sri)
}
const tmp = await makeTmp(cache, opts)
try {
await fs.writeFile(tmp.target, data, { flag: 'wx' })
await moveToDestination(tmp, cache, sri, opts)
return { integrity: sri, size: data.length }
} finally {
if (!tmp.moved) {
await fs.rm(tmp.target, { recursive: true, force: true })
}
}
}
module.exports.stream = writeStream
// writes proxied to the 'inputStream' that is passed to the Promise
// 'end' is deferred until content is handled.
class CacacheWriteStream extends Flush {
constructor (cache, opts) {
super()
this.opts = opts
this.cache = cache
this.inputStream = new Minipass()
this.inputStream.on('error', er => this.emit('error', er))
this.inputStream.on('drain', () => this.emit('drain'))
this.handleContentP = null
}
write (chunk, encoding, cb) {
if (!this.handleContentP) {
this.handleContentP = handleContent(
this.inputStream,
this.cache,
this.opts
)
}
return this.inputStream.write(chunk, encoding, cb)
}
flush (cb) {
this.inputStream.end(() => {
if (!this.handleContentP) {
const e = new Error('Cache input stream was empty')
e.code = 'ENODATA'
// empty streams are probably emitting end right away.
// defer this one tick by rejecting a promise on it.
return Promise.reject(e).catch(cb)
}
// eslint-disable-next-line promise/catch-or-return
this.handleContentP.then(
(res) => {
res.integrity && this.emit('integrity', res.integrity)
// eslint-disable-next-line promise/always-return
res.size !== null && this.emit('size', res.size)
cb()
},
(er) => cb(er)
)
})
}
}
function writeStream (cache, opts = {}) {
return new CacacheWriteStream(cache, opts)
}
async function handleContent (inputStream, cache, opts) {
const tmp = await makeTmp(cache, opts)
try {
const res = await pipeToTmp(inputStream, cache, tmp.target, opts)
await moveToDestination(
tmp,
cache,
res.integrity,
opts
)
return res
} finally {
if (!tmp.moved) {
await fs.rm(tmp.target, { recursive: true, force: true })
}
}
}
async function pipeToTmp (inputStream, cache, tmpTarget, opts) {
const outStream = new fsm.WriteStream(tmpTarget, {
flags: 'wx',
})
if (opts.integrityEmitter) {
// we need to create these all simultaneously since they can fire in any order
const [integrity, size] = await Promise.all([
events.once(opts.integrityEmitter, 'integrity').then(res => res[0]),
events.once(opts.integrityEmitter, 'size').then(res => res[0]),
new Pipeline(inputStream, outStream).promise(),
])
return { integrity, size }
}
let integrity
let size
const hashStream = ssri.integrityStream({
integrity: opts.integrity,
algorithms: opts.algorithms,
size: opts.size,
})
hashStream.on('integrity', i => {
integrity = i
})
hashStream.on('size', s => {
size = s
})
const pipeline = new Pipeline(inputStream, hashStream, outStream)
await pipeline.promise()
return { integrity, size }
}
async function makeTmp (cache, opts) {
const tmpTarget = uniqueFilename(path.join(cache, 'tmp'), opts.tmpPrefix)
await fs.mkdir(path.dirname(tmpTarget), { recursive: true })
return {
target: tmpTarget,
moved: false,
}
}
async function moveToDestination (tmp, cache, sri, opts) {
const destination = contentPath(cache, sri)
const destDir = path.dirname(destination)
await fs.mkdir(destDir, { recursive: true })
await moveFile(tmp.target, destination)
tmp.moved = true
}
function sizeError (expected, found) {
/* eslint-disable-next-line max-len */
const err = new Error(`Bad data size: expected inserted data to be ${expected} bytes, but got ${found} instead`)
err.expected = expected
err.found = found
err.code = 'EBADSIZE'
return err
}
function checksumError (expected, found) {
const err = new Error(`Integrity check failed:
Wanted: ${expected}
Found: ${found}`)
err.code = 'EINTEGRITY'
err.expected = expected
err.found = found
return err
}
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