1 files changed, 206 insertions, 0 deletions
diff --git a/nixpkgs/pkgs/build-support/node/fetch-yarn-deps/index.js b/nixpkgs/pkgs/build-support/node/fetch-yarn-deps/index.js
new file mode 100755
index 000000000000..e60fdeb54330
--- /dev/null
+++ b/nixpkgs/pkgs/build-support/node/fetch-yarn-deps/index.js
@@ -0,0 +1,206 @@
+#!/usr/bin/env node
+'use strict'
+
+const fs = require('fs')
+const crypto = require('crypto')
+const process = require('process')
+const https = require('https')
+const child_process = require('child_process')
+const path = require('path')
+const lockfile = require('./yarnpkg-lockfile.js')
+const { promisify } = require('util')
+const url = require('url')
+const { urlToName } = require('./common.js')
+
+const execFile = promisify(child_process.execFile)
+
+const exec = async (...args) => {
+	const res = await execFile(...args)
+	if (res.error) throw new Error(res.stderr)
+	return res
+}
+
+const downloadFileHttps = (fileName, url, expectedHash, hashType = 'sha1') => {
+	return new Promise((resolve, reject) => {
+		const get = (url, redirects = 0) => https.get(url, (res) => {
+			if(redirects > 10) {
+				reject('Too many redirects!');
+				return;
+			}
+			if(res.statusCode === 301 || res.statusCode === 302) {
+				return get(res.headers.location, redirects + 1)
+			}
+			const file = fs.createWriteStream(fileName)
+			const hash = crypto.createHash(hashType)
+			res.pipe(file)
+			res.pipe(hash).setEncoding('hex')
+			res.on('end', () => {
+				file.close()
+				const h = hash.read()
+				if (expectedHash === undefined){
+					console.log(`Warning: lockfile url ${url} doesn't end in "#<hash>" to validate against. Downloaded file had hash ${h}.`);
+				} else if (h != expectedHash) return reject(new Error(`hash mismatch, expected ${expectedHash}, got ${h}`))
+				resolve()
+			})
+                        res.on('error', e => reject(e))
+		})
+		get(url)
+	})
+}
+
+const downloadGit = async (fileName, url, rev) => {
+	await exec('nix-prefetch-git', [
+		'--out', fileName + '.tmp',
+		'--url', url,
+		'--rev', rev,
+		'--builder'
+	])
+
+	await exec('tar', [
+		// hopefully make it reproducible across runs and systems
+		'--owner=0', '--group=0', '--numeric-owner', '--format=gnu', '--sort=name', '--mtime=@1',
+
+		// Set u+w because tar-fs can't unpack archives with read-only dirs: https://github.com/mafintosh/tar-fs/issues/79
+		'--mode', 'u+w',
+
+		'-C', fileName + '.tmp',
+		'-cf', fileName, '.'
+	])
+
+	await exec('rm', [ '-rf', fileName + '.tmp', ])
+}
+
+const isGitUrl = pattern => {
+	// https://github.com/yarnpkg/yarn/blob/3119382885ea373d3c13d6a846de743eca8c914b/src/resolvers/exotics/git-resolver.js#L15-L47
+	const GIT_HOSTS = ['github.com', 'gitlab.com', 'bitbucket.com', 'bitbucket.org']
+	const GIT_PATTERN_MATCHERS = [/^git:/, /^git\+.+:/, /^ssh:/, /^https?:.+\.git$/, /^https?:.+\.git#.+/]
+
+	for (const matcher of GIT_PATTERN_MATCHERS) if (matcher.test(pattern)) return true
+
+	const {hostname, path} = url.parse(pattern)
+	if (hostname && path && GIT_HOSTS.indexOf(hostname) >= 0
+		// only if dependency is pointing to a git repo,
+		// e.g. facebook/flow and not file in a git repo facebook/flow/archive/v1.0.0.tar.gz
+		&& path.split('/').filter(p => !!p).length === 2
+	) return true
+
+	return false
+}
+
+const downloadPkg = (pkg, verbose) => {
+	const fileMarker = '@file:'
+	const split = pkg.key.split(fileMarker)
+	if (split.length == 2) {
+		console.info(`ignoring lockfile entry "${split[0]}" which points at path "${split[1]}"`)
+		return
+	} else if (split.length > 2) {
+		throw new Error(`The lockfile entry key "${pkg.key}" contains "${fileMarker}" more than once. Processing is not implemented.`)
+	}
+
+	if (pkg.resolved === undefined) {
+		throw new Error(`The lockfile entry with key "${pkg.key}" cannot be downloaded because it is missing the "resolved" attribute, which should contain the URL to download from. The lockfile might be invalid.`)
+	}
+
+	const [ url, hash ] = pkg.resolved.split('#')
+	if (verbose) console.log('downloading ' + url)
+	const fileName = urlToName(url)
+	if (url.startsWith('https://codeload.github.com/') && url.includes('/tar.gz/')) {
+		const s = url.split('/')
+		return downloadGit(fileName, `https://github.com/${s[3]}/${s[4]}.git`, s[s.length-1])
+	} else if (url.startsWith('https://github.com/') && url.endsWith('.tar.gz')) {
+		const s = url.split('/')
+		return downloadGit(fileName, `https://github.com/${s[3]}/${s[4]}.git`, s[s.length-1].replace(/.tar.gz$/, ''))
+	} else if (isGitUrl(url)) {
+		return downloadGit(fileName, url.replace(/^git\+/, ''), hash)
+	} else if (url.startsWith('https://')) {
+		if (typeof pkg.integrity === 'string' || pkg.integrity instanceof String) {
+			const [ type, checksum ] = pkg.integrity.split('-')
+			return downloadFileHttps(fileName, url, Buffer.from(checksum, 'base64').toString('hex'), type)
+		}
+		return downloadFileHttps(fileName, url, hash)
+	} else if (url.startsWith('file:')) {
+		console.warn(`ignoring unsupported file:path url "${url}"`)
+	} else {
+		throw new Error('don\'t know how to download "' + url + '"')
+	}
+}
+
+const performParallel = tasks => {
+	const worker = async () => {
+		while (tasks.length > 0) await tasks.shift()()
+	}
+
+	const workers = []
+	for (let i = 0; i < 4; i++) {
+		workers.push(worker())
+	}
+
+	return Promise.all(workers)
+}
+
+const prefetchYarnDeps = async (lockContents, verbose) => {
+	const lockData = lockfile.parse(lockContents)
+	await performParallel(
+		Object.entries(lockData.object)
+		.map(([key, value]) => () => downloadPkg({ key, ...value }, verbose))
+	)
+	await fs.promises.writeFile('yarn.lock', lockContents)
+	if (verbose) console.log('Done')
+}
+
+const showUsage = async () => {
+	process.stderr.write(`
+syntax: prefetch-yarn-deps [path to yarn.lock] [options]
+
+Options:
+  -h --help         Show this help
+  -v --verbose      Verbose output
+  --builder         Only perform the download to current directory, then exit
+`)
+	process.exit(1)
+}
+
+const main = async () => {
+	const args = process.argv.slice(2)
+	let next, lockFile, verbose, isBuilder
+	while (next = args.shift()) {
+		if (next == '--builder') {
+			isBuilder = true
+		} else if (next == '--verbose' || next == '-v') {
+			verbose = true
+		} else if (next == '--help' || next == '-h') {
+			showUsage()
+		} else if (!lockFile) {
+			lockFile = next
+		} else {
+			showUsage()
+		}
+	}
+	let lockContents
+	try {
+		lockContents = await fs.promises.readFile(lockFile || 'yarn.lock', 'utf-8')
+	} catch {
+		showUsage()
+	}
+
+	if (isBuilder) {
+		await prefetchYarnDeps(lockContents, verbose)
+	} else {
+		const { stdout: tmpDir } = await exec('mktemp', [ '-d' ])
+
+		try {
+			process.chdir(tmpDir.trim())
+			await prefetchYarnDeps(lockContents, verbose)
+			const { stdout: hash } = await exec('nix-hash', [ '--type', 'sha256', '--base32', tmpDir.trim() ])
+			console.log(hash)
+		} finally {
+			await exec('rm', [ '-rf', tmpDir.trim() ])
+		}
+	}
+}
+
+main()
+	.catch(e => {
+		console.error(e)
+		process.exit(1)
+	})