Replace defer() with Future.of in pub.

Review URL: https://codereview.chromium.org//13196007

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@20703 260f80e4-7a28-3924-810f-c04153c831b5

utils/pub/command_uploader.dart

@@ -59,7 +59,7 @@ class UploaderCommand extends PubCommand {
       exit(exit_codes.USAGE);
     }
 
-    return defer(() {
+    return new Future.of(() {
       var package = commandOptions['package'];
       if (package != null) return package;
       return new Entrypoint(path.current, cache).root.name;

utils/pub/entrypoint.dart

@@ -71,7 +71,7 @@ class Entrypoint {
     if (pendingOrCompleted != null) return pendingOrCompleted;
 
     var packageDir = path.join(packagesDir, id.name);
-    var future = defer(() {
+    var future = new Future.of(() {
       ensureDir(path.dirname(packageDir));
 
       if (entryExists(packageDir)) {
@@ -102,7 +102,7 @@ class Entrypoint {
   /// directory, respecting the [LockFile] if present. Returns a [Future] that
   /// completes when all dependencies are installed.
   Future installDependencies() {
-    return defer(() {
+    return new Future.of(() {
       return resolveVersions(cache.sources, root, loadLockFile());
     }).then(_installDependencies);
   }
@@ -119,7 +119,7 @@ class Entrypoint {
   /// other dependencies as specified by the [LockFile] if possible. Returns a
   /// [Future] that completes when all dependencies are installed.
   Future updateDependencies(List<String> dependencies) {
-    return defer(() {
+    return new Future.of(() {
       var solver = new VersionSolver(cache.sources, root, loadLockFile());
       for (var dependency in dependencies) {
         solver.useLatestVersion(dependency);
@@ -148,7 +148,7 @@ class Entrypoint {
   /// reached packages. This should only be called after the lockfile has been
   /// successfully generated.
   Future<List<Pubspec>> walkDependencies() {
-    return defer(() {
+    return new Future.of(() {
       var lockFile = loadLockFile();
       var group = new FutureGroup<Pubspec>();
       var visited = new Set<String>();

utils/pub/error_group.dart

@@ -264,7 +264,7 @@ class _ErrorGroupStream extends Stream {
     if (_isDone) return;
     _subscription.cancel();
     // Call these asynchronously to work around issue 7913.
-    defer(() {
+    new Future.immediate(null).then((_) {
       _controller.addError(e.error, e.stackTrace);
       _controller.close();
     });

utils/pub/git_source.dart

@@ -123,7 +123,7 @@ class GitSource extends Source {
   /// future that completes once this is finished and throws an exception if it
   /// fails.
   Future _ensureRepoCache(PackageId id) {
-    return defer(() {
+    return new Future.of(() {
       var path = _repoCachePath(id);
       if (!entryExists(path)) return _clone(_getUrl(id), path, mirror: true);
       return git.run(["fetch"], workingDir: path).then((result) => null);
@@ -143,7 +143,7 @@ class GitSource extends Source {
   /// the working tree, but instead makes the repository a local mirror of the
   /// remote repository. See the manpage for `git clone` for more information.
   Future _clone(String from, String to, {bool mirror: false}) {
-    return defer(() {
+    return new Future.of(() {
       // Git on Windows does not seem to automatically create the destination
       // directory.
       ensureDir(to);

utils/pub/hosted_source.dart

@@ -63,7 +63,7 @@ class HostedSource extends Source {
 
   /// Downloads a package from the site and unpacks it.
   Future<bool> install(PackageId id, String destPath) {
-    return defer(() {
+    return new Future.of(() {
       var url = _makeVersionUrl(id, (server, package, version) =>
           "$server/packages/$package/versions/$version.tar.gz");
       log.io("Install package from $url.");

utils/pub/io.dart

@@ -550,7 +550,7 @@ Future timeout(Future input, int milliseconds, String description) {
 /// Returns a future that completes to the value that the future returned from
 /// [fn] completes to.
 Future withTempDir(Future fn(String path)) {
-  return defer(() {
+  return new Future.of(() {
     var tempDir = createTempDir();
     return new Future.of(() => fn(tempDir))
         .whenComplete(() => deleteEntry(tempDir));

utils/pub/oauth2.dart

@@ -104,7 +104,7 @@ Future withClient(SystemCache cache, Future fn(Client client)) {
 /// Gets a new OAuth2 client. If saved credentials are available, those are
 /// used; otherwise, the user is prompted to authorize the pub client.
 Future<Client> _getClient(SystemCache cache) {
-  return defer(() {
+  return new Future.of(() {
     var credentials = _loadCredentials(cache);
     if (credentials == null) return _authorize();
 

utils/pub/path_source.dart

@@ -25,7 +25,7 @@ class PathSource extends Source {
   final shouldCache = false;
 
   Future<Pubspec> describe(PackageId id) {
-    return defer(() {
+    return new Future.of(() {
       _validatePath(id.name, id.description);
       return new Pubspec.load(id.name, id.description["path"],
           systemCache.sources);
@@ -40,7 +40,7 @@ class PathSource extends Source {
   }
 
   Future<bool> install(PackageId id, String destination) {
-    return defer(() {
+    return new Future.of(() {
       try {
         _validatePath(id.name, id.description);
       } on FormatException catch(err) {

utils/pub/pub.dart

@@ -145,7 +145,7 @@ main() {
 /// Checks that pub is running on a supported platform. If it isn't, it prints
 /// an error message and exits. Completes when the validation is done.
 Future validatePlatform() {
-  return defer(() {
+  return new Future.of(() {
     if (Platform.operatingSystem != 'windows') return;
 
     return runProcess('ver', []).then((result) {
@@ -265,7 +265,7 @@ abstract class PubCommand {
       exit(_chooseExitCode(error));
     }
 
-    defer(() {
+    new Future.of(() {
       if (requiresEntrypoint) {
         // TODO(rnystrom): Will eventually need better logic to walk up
         // subdirectories until we hit one that looks package-like. For now,

utils/pub/utils.dart

@@ -145,18 +145,6 @@ String sha1(String source) {
   return CryptoUtils.bytesToHex(sha.close());
 }
 
-// TODO(nweiz): Use Future.of instead of this wherever we don't actually need
-// asynchrony.
-/// Invokes the given callback asynchronously. Returns a [Future] that completes
-/// to the result of [callback].
-///
-/// This is also used to wrap synchronous code that may thrown an exception to
-/// ensure that methods that have both sync and async code only report errors
-/// asynchronously.
-Future defer(callback()) {
-  return new Future.immediate(null).then((_) => callback());
-}
-
 /// Returns a [Future] that completes in [milliseconds].
 Future sleep(int milliseconds) {
   var completer = new Completer();

utils/tests/pub/test_pub.dart

@@ -579,7 +579,7 @@ Future<Pair<List<String>, List<String>>> schedulePackageValidation(
   return schedule(() {
     var cache = new SystemCache.withSources(path.join(sandboxDir, cachePath));
 
-    return defer(() {
+    return new Future.of(() {
       var validator = fn(new Entrypoint(path.join(sandboxDir, appPath), cache));
       return validator.validate().then((_) {
         return new Pair(validator.errors, validator.warnings);

utils/tests/pub/version_solver_test.dart

@@ -481,13 +481,11 @@ class MockSource extends Source {
       : _packages = <String, Map<Version, Package>>{};
 
   Future<List<Version>> getVersions(String name, String description) {
-    return defer(() => _packages[description].keys.toList());
+    return new Future.of(() => _packages[description].keys.toList());
   }
 
   Future<Pubspec> describe(PackageId id) {
-    return defer(() {
-      return _packages[id.name][id.version].pubspec;
-    });
+    return new Future.of(() => _packages[id.name][id.version].pubspec);
   }
 
   Future<bool> install(PackageId id, String path) {