Command to print paths to dependencies.

sdk/lib/_internal/pub/lib/src/command/list_package_dirs.dart

Index: sdk/lib/_internal/pub/lib/src/command/list_package_dirs.dart
diff --git a/sdk/lib/_internal/pub/lib/src/command/list_package_dirs.dart b/sdk/lib/_internal/pub/lib/src/command/list_package_dirs.dart
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+// Copyright (c) 2013, 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 pub.command.list_package_dirs;
+
+import 'dart:async';
+import 'dart:io';
+import 'dart:json' as json;
+
+import '../command.dart';
+import '../exit_codes.dart' as exit_codes;
+import '../log.dart' as log;
+
+/// Handles the `list-package-dirs` pub command.
+class ListPackageDirsCommand extends PubCommand {
+  String get description => "Print local paths to dependencies.";
+  String get usage => "pub list-package-dirs";
+  bool get hidden => true;
+
+  ListPackageDirsCommand() {
+    commandParser.addOption("format",
+        help: "How output should be displayed.",
+        allowed: ["json"]);
+  }
+
+  Future onRun() {
+    if (!entrypoint.lockFileExists) {
+      log.error(json.stringify(
+          'Package "myapp" has no lockfile. Please run "pub install" first.'));
+      exit(exit_codes.NO_INPUT);
+    }
+
+    var output = {};
+    var futures = [];
+    entrypoint.loadLockFile().packages.forEach((name, package) {
+      var source = entrypoint.cache.sources[package.source];
+      futures.add(source.getDirectory(package).then((packageDir) {
+        output[name] = packageDir;
+      }));
+    });
+
+    return Future.wait(futures).then((_) {
+      log.message(json.stringify(output));
+    });
+  }
+}
+