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read.js
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read.js
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'use strict'
const fs = require('fs/promises')
const fsm = require('fs-minipass')
const ssri = require('ssri')
const contentPath = require('./path')
const Pipeline = require('minipass-pipeline')
module.exports = read
const MAX_SINGLE_READ_SIZE = 64 * 1024 * 1024
async function read (cache, integrity, opts = {}) {
const { size } = opts
const { stat, cpath, sri } = await withContentSri(cache, integrity, async (cpath, sri) => {
// get size
const stat = size ? { size } : await fs.stat(cpath)
return { stat, cpath, sri }
})
if (stat.size > MAX_SINGLE_READ_SIZE) {
return readPipeline(cpath, stat.size, sri, new Pipeline()).concat()
}
const data = await fs.readFile(cpath, { encoding: null })
if (stat.size !== data.length) {
throw sizeError(stat.size, data.length)
}
if (!ssri.checkData(data, sri)) {
throw integrityError(sri, cpath)
}
return data
}
const readPipeline = (cpath, size, sri, stream) => {
stream.push(
new fsm.ReadStream(cpath, {
size,
readSize: MAX_SINGLE_READ_SIZE,
}),
ssri.integrityStream({
integrity: sri,
size,
})
)
return stream
}
module.exports.stream = readStream
module.exports.readStream = readStream
function readStream (cache, integrity, opts = {}) {
const { size } = opts
const stream = new Pipeline()
// Set all this up to run on the stream and then just return the stream
Promise.resolve().then(async () => {
const { stat, cpath, sri } = await withContentSri(cache, integrity, async (cpath, sri) => {
// get size
const stat = size ? { size } : await fs.stat(cpath)
return { stat, cpath, sri }
})
return readPipeline(cpath, stat.size, sri, stream)
}).catch(err => stream.emit('error', err))
return stream
}
module.exports.copy = copy
function copy (cache, integrity, dest) {
return withContentSri(cache, integrity, (cpath, sri) => {
return fs.copyFile(cpath, dest)
})
}
module.exports.hasContent = hasContent
async function hasContent (cache, integrity) {
if (!integrity) {
return false
}
try {
return await withContentSri(cache, integrity, async (cpath, sri) => {
const stat = await fs.stat(cpath)
return { size: stat.size, sri, stat }
})
} catch (err) {
if (err.code === 'ENOENT') {
return false
}
if (err.code === 'EPERM') {
/* istanbul ignore else */
if (process.platform !== 'win32') {
throw err
} else {
return false
}
}
}
}
async function withContentSri (cache, integrity, fn) {
const sri = ssri.parse(integrity)
// If `integrity` has multiple entries, pick the first digest
// with available local data.
const algo = sri.pickAlgorithm()
const digests = sri[algo]
if (digests.length <= 1) {
const cpath = contentPath(cache, digests[0])
return fn(cpath, digests[0])
} else {
// Can't use race here because a generic error can happen before
// a ENOENT error, and can happen before a valid result
const results = await Promise.all(digests.map(async (meta) => {
try {
return await withContentSri(cache, meta, fn)
} catch (err) {
if (err.code === 'ENOENT') {
return Object.assign(
new Error('No matching content found for ' + sri.toString()),
{ code: 'ENOENT' }
)
}
return err
}
}))
// Return the first non error if it is found
const result = results.find((r) => !(r instanceof Error))
if (result) {
return result
}
// Throw the No matching content found error
const enoentError = results.find((r) => r.code === 'ENOENT')
if (enoentError) {
throw enoentError
}
// Throw generic error
throw results.find((r) => r instanceof Error)
}
}
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 integrityError (sri, path) {
const err = new Error(`Integrity verification failed for ${sri} (${path})`)
err.code = 'EINTEGRITY'
err.sri = sri
err.path = path
return err
}