Use gunzip-maybe instead of reimplementing (#2971)

package.json

@@ -15,6 +15,7 @@
     "death": "^1.0.0",
     "debug": "^2.2.0",
     "detect-indent": "^5.0.0",
+    "gunzip-maybe": "^1.4.0",
     "ini": "^1.3.4",
     "inquirer": "^3.0.1",
     "invariant": "^2.2.0",

src/fetchers/tarball-fetcher.js

@@ -3,7 +3,6 @@
 import http from 'http';
 import {SecurityError, MessageError} from '../errors.js';
 import type {FetchedOverride} from '../types.js';
-import {UnpackStream} from '../util/stream.js';
 import * as constants from '../constants.js';
 import * as crypto from '../util/crypto.js';
 import BaseFetcher from './base-fetcher.js';
@@ -13,6 +12,8 @@ const path = require('path');
 const tarFs = require('tar-fs');
 const url = require('url');
 const fs = require('fs');
+const stream = require('stream');
+const gunzip = require('gunzip-maybe');
 
 export default class TarballFetcher extends BaseFetcher {
   async setupMirrorFromCache(): Promise<?string> {
@@ -70,10 +71,10 @@ export default class TarballFetcher extends BaseFetcher {
     reject: (error: Error) => void,
   ): {
     validateStream: crypto.HashStream,
-    extractorStream: UnpackStream,
+    extractorStream: stream.Transform,
   } {
     const validateStream = new crypto.HashStream();
-    const extractorStream = new UnpackStream();
+    const extractorStream = gunzip();
     const untarStream = tarFs.extract(this.dest, {
       strip: 1,
       dmode: 0o555, // all dirs should be readable

src/util/stream.js

@@ -2,59 +2,6 @@
 
 const invariant = require('invariant');
 const stream = require('stream');
-const zlib = require('zlib');
-
-function hasGzipHeader(chunk: Buffer): boolean {
-  return chunk[0] === 0x1F && chunk[1] === 0x8B && chunk[2] === 0x08;
-}
-
-type UnpackOptions = duplexStreamOptions;
-
-export class UnpackStream extends stream.Transform {
-  constructor(options?: UnpackOptions) {
-    super(options);
-    this._srcStream = null;
-    this._readHeader = false;
-    this.once('pipe', (src: stream.Readable) => {
-      this._srcStream = src;
-    });
-  }
-
-  _srcStream: ?stream.Readable;
-  _readHeader: boolean;
-
-  _transform(
-    chunk: Buffer | string,
-    encoding: string,
-    callback: (error: ?Error, data?: Buffer | string) => void,
-  ) {
-    if (!this._readHeader) {
-      this._readHeader = true;
-      invariant(chunk instanceof Buffer, 'Chunk must be a buffer');
-      if (hasGzipHeader(chunk)) {
-        // Stop receiving data from the src stream, and pipe it instead to zlib,
-        // then pipe it's output through us.
-        const unzipStream = zlib.createUnzip();
-        unzipStream.on('error', (err) => this.emit('error', err));
-
-        const srcStream = this._srcStream;
-        invariant(srcStream, 'How? To get here a stream must have been piped!');
-        srcStream
-          .pipe(unzipStream)
-          .pipe(this);
-
-        // Unpipe after another stream has been piped so it's always piping to
-        // something, thus avoiding pausing it.
-        srcStream.unpipe(this);
-        unzipStream.write(chunk);
-        this._srcStream = null;
-        callback();
-        return;
-      }
-    }
-    callback(null, chunk);
-  }
-}
 
 export class ConcatStream extends stream.Transform {
   constructor(done: (buf: Buffer) => void) {

yarn.lock

@@ -1347,7 +1347,7 @@ duplexer2@0.0.2:
   dependencies:
     readable-stream "~1.1.9"
 
-duplexify@^3.5.0:
+duplexify@^3.1.2, duplexify@^3.5.0:
   version "3.5.0"
   resolved "https://registry.yarnpkg.com/duplexify/-/duplexify-3.5.0.tgz#1aa773002e1578457e9d9d4a50b0ccaaebcbd604"
   dependencies:
@@ -2161,6 +2161,17 @@ gulplog@^1.0.0:
   dependencies:
     glogg "^1.0.0"
 
+gunzip-maybe@^1.4.0:
+  version "1.4.0"
+  resolved "https://registry.yarnpkg.com/gunzip-maybe/-/gunzip-maybe-1.4.0.tgz#7d8316c8d0571e1d08a5a79e46fff0afe8172b19"
+  dependencies:
+    browserify-zlib "^0.1.4"
+    is-deflate "^1.0.0"
+    is-gzip "^1.0.0"
+    peek-stream "^1.1.0"
+    pumpify "^1.3.3"
+    through2 "^2.0.3"
+
 handlebars@^4.0.3:
   version "4.0.6"
   resolved "https://registry.yarnpkg.com/handlebars/-/handlebars-4.0.6.tgz#2ce4484850537f9c97a8026d5399b935c4ed4ed7"
@@ -2390,6 +2401,10 @@ is-ci@^1.0.10, is-ci@^1.0.9:
   dependencies:
     ci-info "^1.0.0"
 
+is-deflate@^1.0.0:
+  version "1.0.0"
+  resolved "https://registry.yarnpkg.com/is-deflate/-/is-deflate-1.0.0.tgz#c862901c3c161fb09dac7cdc7e784f80e98f2f14"
+
 is-dotfile@^1.0.0:
   version "1.0.2"
   resolved "https://registry.yarnpkg.com/is-dotfile/-/is-dotfile-1.0.2.tgz#2c132383f39199f8edc268ca01b9b007d205cc4d"
@@ -2440,6 +2455,10 @@ is-glob@^3.1.0:
   dependencies:
     is-extglob "^2.1.0"
 
+is-gzip@^1.0.0:
+  version "1.0.0"
+  resolved "https://registry.yarnpkg.com/is-gzip/-/is-gzip-1.0.0.tgz#6ca8b07b99c77998025900e555ced8ed80879a83"
+
 is-my-json-valid@^2.10.0:
   version "2.16.0"
   resolved "https://registry.yarnpkg.com/is-my-json-valid/-/is-my-json-valid-2.16.0.tgz#f079dd9bfdae65ee2038aae8acbc86ab109e3693"
@@ -3598,6 +3617,13 @@ pbkdf2@^3.0.3:
   dependencies:
     create-hmac "^1.1.2"
 
+peek-stream@^1.1.0:
+  version "1.1.2"
+  resolved "https://registry.yarnpkg.com/peek-stream/-/peek-stream-1.1.2.tgz#97eb76365bcfd8c89e287f55c8b69d4c3e9bcc52"
+  dependencies:
+    duplexify "^3.5.0"
+    through2 "^2.0.3"
+
 performance-now@^0.2.0:
   version "0.2.0"
   resolved "https://registry.yarnpkg.com/performance-now/-/performance-now-0.2.0.tgz#33ef30c5c77d4ea21c5a53869d91b56d8f2555e5"
@@ -3688,6 +3714,14 @@ pump@^1.0.0:
     end-of-stream "^1.1.0"
     once "^1.3.1"
 
+pumpify@^1.3.3:
+  version "1.3.5"
+  resolved "https://registry.yarnpkg.com/pumpify/-/pumpify-1.3.5.tgz#1b671c619940abcaeac0ad0e3a3c164be760993b"
+  dependencies:
+    duplexify "^3.1.2"
+    inherits "^2.0.1"
+    pump "^1.0.0"
+
 punycode@1.3.2:
   version "1.3.2"
   resolved "https://registry.yarnpkg.com/punycode/-/punycode-1.3.2.tgz#9653a036fb7c1ee42342f2325cceefea3926c48d"
@@ -4360,7 +4394,7 @@ throat@^3.0.0:
   version "3.0.0"
   resolved "https://registry.yarnpkg.com/throat/-/throat-3.0.0.tgz#e7c64c867cbb3845f10877642f7b60055b8ec0d6"
 
-through2@2.X, through2@^2, through2@^2.0.0, through2@^2.0.1:
+through2@2.X, through2@^2, through2@^2.0.0, through2@^2.0.1, through2@^2.0.3:
   version "2.0.3"
   resolved "https://registry.yarnpkg.com/through2/-/through2-2.0.3.tgz#0004569b37c7c74ba39c43f3ced78d1ad94140be"
   dependencies: