Revert "Fix extraction race condition"

This reverts commit 4aba460a63.

server/middleware/RegistryUtils.js

@@ -4,7 +4,7 @@ const mkdirp = require('mkdirp')
 const tar = require('tar-fs')
 const RegistryCache = require('./RegistryCache')
 
-const fetchPackageInfoFromRegistry = (registryURL, packageName) => {
+const getPackageInfoFromRegistry = (registryURL, packageName) => {
   let encodedPackageName
   if (packageName.charAt(0) === '@') {
     encodedPackageName = `@${encodeURIComponent(packageName.substring(1))}`
@@ -23,15 +23,14 @@ const fetchPackageInfoFromRegistry = (registryURL, packageName) => {
 
 const PackageNotFound = 'PackageNotFound'
 
-const fetchPackageInfo = (registryURL, packageName) =>
+const getPackageInfo = (registryURL, packageName, callback) => {
-  new Promise((resolve, reject) => {
   RegistryCache.get(packageName, (error, value) => {
     if (error) {
-        reject(error)
+      callback(error)
     } else if (value) {
-        resolve(value === PackageNotFound ? null : value)
+      callback(null, value === PackageNotFound ? null : value)
     } else {
-        fetchPackageInfoFromRegistry(registryURL, packageName).then(value => {
+      getPackageInfoFromRegistry(registryURL, packageName).then(value => {
         if (value == null) {
           // Keep 404s in the cache for 5 minutes. This prevents us
           // from making unnecessary requests to the registry for
@@ -43,15 +42,15 @@ const fetchPackageInfo = (registryURL, packageName) =>
           RegistryCache.set(packageName, value, 60)
         }
 
-          resolve(value)
+        callback(null, value)
       }, error => {
         // Do not cache errors.
         RegistryCache.del(packageName)
-          reject(error)
+        callback(error)
       })
     }
   })
-  })
+}
 
 const normalizeTarHeader = (header) => {
   // Most packages have header names that look like "package/index.js"
@@ -62,12 +61,13 @@ const normalizeTarHeader = (header) => {
   return header
 }
 
-const fetchAndExtractPackage = (tarballURL, outputDir) =>
+const getPackage = (tarballURL, outputDir, callback) => {
-  new Promise((resolve, reject) => {
   mkdirp(outputDir, (error) => {
     if (error) {
-        reject(error)
+      callback(error)
     } else {
+      let callbackWasCalled = false
+
       fetch(tarballURL).then(response => {
         response.body
           .pipe(gunzip())
@@ -78,46 +78,19 @@ const fetchAndExtractPackage = (tarballURL, outputDir) =>
               map: normalizeTarHeader
             })
           )
-            .on('finish', resolve)
+          .on('finish', callback)
-            .on('error', reject)
+          .on('error', (error) => {
-        }, reject)
+            if (callbackWasCalled) // LOL node streams
-      }
+              return
+
+            callbackWasCalled = true
+            callback(error)
           })
       })
-
+    }
-const runCache = {}
-
-// A helper that prevents running multiple async operations
-// identified by the same key concurrently. Instead, the operation
-// is performed only once the first time it is requested and all
-// subsequent calls get that same result until it is completed.
-const runOnce = (key, perform) => {
-  let promise = runCache[key]
-
-  if (!promise) {
-    promise = runCache[key] = perform()
-
-    // Clear the cache when we're done.
-    promise.then(() => {
-      delete runCache[key]
-    }, () => {
-      delete runCache[key]
   })
 }
 
-  return promise
-}
-
-const getPackageInfo = (registryURL, packageName, callback) => {
-  runOnce(registryURL + packageName, () => fetchPackageInfo(registryURL, packageName))
-    .then(info => callback(null, info), callback)
-}
-
-const getPackage = (tarballURL, outputDir, callback) => {
-  runOnce(tarballURL + outputDir, () => fetchAndExtractPackage(tarballURL, outputDir))
-    .then(() => callback(null), callback)
-}
-
 module.exports = {
   getPackageInfo,
   getPackage

server/middleware/index.js

@@ -22,11 +22,14 @@ const oneMinute = 60
 const oneDay = oneMinute * 60 * 24
 const oneYear = oneDay * 365
 
-const checkLocalCache = (dir, filename, callback) =>
+const checkLocalCache = (dir, callback) =>
-  statFile(joinPaths(dir, filename || 'package.json'), (error, stats) => {
+  statFile(joinPaths(dir, 'package.json'), (error, stats) => {
     callback(stats && stats.isFile())
   })
 
+const createTempPath = (name) =>
+  joinPaths(tmpdir(), `unpkg-${name}`)
+
 const ResolveExtensions = [ '', '.js', '.json' ]
 
 /**
@@ -107,9 +110,9 @@ const createRequestHandler = (options = {}) => {
     // Step 1: Fetch the package from the registry and store a local copy.
     // Redirect if the URL does not specify an exact version number.
     const fetchPackage = (next) => {
-      const packageDir = joinPaths(tmpdir(), `unpkg-${displayName}`)
+      const packageDir = createTempPath(displayName)
 
-      checkLocalCache(packageDir, filename, (isCached) => {
+      checkLocalCache(packageDir, (isCached) => {
         if (isCached)
           return next(packageDir) // Best case: we already have this package on disk.