Make createTempDir() synchronous.

utils/pub/hosted_source.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library hosted_source;
 
 import 'dart:async';
 import 'dart:io' as io;
 import 'dart:json' as json;
 import 'dart:uri';
@@ skipping 44 matching lines @@
 
     return httpClient.read(fullUrl).then((yaml) {
       return new Pubspec.parse(yaml, systemCache.sources);
     }).catchError((ex) {
       _throwFriendlyError(ex, id, parsed.last);
     });
   }
 
   /// Downloads a package from the site and unpacks it.
   Future<bool> install(PackageId id, String destPath) {
-    var parsedDescription = _parseDescription(id.description);
-    var name = parsedDescription.first;
-    var url = parsedDescription.last;
+    return defer(() {
+      var parsedDescription = _parseDescription(id.description);
+      var name = parsedDescription.first;
+      var url = parsedDescription.last;
 
-    var fullUrl = "$url/packages/$name/versions/${id.version}.tar.gz";
+      var fullUrl = "$url/packages/$name/versions/${id.version}.tar.gz";
 
-    log.message('Downloading $id...');
+      log.message('Downloading $id...');
 
-    // Download and extract the archive to a temp directory.
-    var tempDir;
-    return Future.wait([
-      httpClient.send(new http.Request("GET", Uri.parse(fullUrl)))
-          .then((response) => response.stream),
-      systemCache.createTempDir()
-    ]).then((args) {
-      var stream = args[0];
-      tempDir = args[1];
-      return timeout(extractTarGz(stream, tempDir), HTTP_TIMEOUT,
-          'fetching URL "$fullUrl"');
-    }).then((_) {
-      // Now that the install has succeeded, move it to the real location in
-      // the cache. This ensures that we don't leave half-busted ghost
-      // directories in the user's pub cache if an install fails.
-      return renameDir(tempDir, destPath);
-    }).then((_) => true);
+      // Download and extract the archive to a temp directory.
+      var tempDir = systemCache.createTempDir();
+      return httpClient.send(new http.Request("GET", Uri.parse(fullUrl)))
+          .then((response) => response.stream)
+          .then((stream) {
+        return timeout(extractTarGz(stream, tempDir), HTTP_TIMEOUT,
+            'fetching URL "$fullUrl"');
+      }).then((_) {
+        // Now that the install has succeeded, move it to the real location in
+        // the cache. This ensures that we don't leave half-busted ghost
+        // directories in the user's pub cache if an install fails.
+        return renameDir(tempDir, destPath);
+      }).then((_) => true);
+    });
   }
 
   /// The system cache directory for the hosted source contains subdirectories
   /// for each separate repository URL that's used on the system. Each of these
   /// subdirectories then contains a subdirectory for each package installed
   /// from that site.
   Future<String> systemCacheDirectory(PackageId id) {
     var parsed = _parseDescription(id.description);
     var url = parsed.last.replaceAll(new RegExp(r"^https?://"), "");
     var urlDir = replace(url, new RegExp(r'[<>:"\\/|?*%]'), (match) {
@@ skipping 61 matching lines @@
 
     var name = description["name"];
     if (name is! String) {
       throw new FormatException("The 'name' key must have a string value.");
     }
 
     var url = description.containsKey("url") ? description["url"] : defaultUrl;
     return new Pair<String, String>(name, url);
   }
 }