Correctly handle case where we have a library outside of a package.

pkg/docgen/lib/src/package_helpers.dart

 // Copyright (c) 2014, 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 docgen.package_helpers;
 
 import 'exports/source_mirrors.dart';
+import 'generator.dart' show pubScript;
 
 import 'dart:io';
 import 'package:path/path.dart' as path;
 import 'package:yaml/yaml.dart';
 
 /// Helper accessor to determine the full pathname of the root of the dart
 /// checkout. We can be in one of three situations:
 /// 1) Running from pkg/docgen/bin/docgen.dart
 /// 2) Running from a snapshot in a build,
 ///   e.g. xcodebuild/ReleaseIA32/dart-sdk/bin
@@ skipping 33 matching lines @@
   // We only want components that are somewhere underneath the lib directory.
   var subPath = path.relative(file, from: possiblePackage);
   var subPathComponents = path.split(subPath);
   if (subPathComponents.isNotEmpty && subPathComponents.first == 'lib') {
     return possiblePackage;
   } else {
     return null;
   }
 }
 
-/// Read a pubspec and return the library name, given a directory
-String packageNameFor(String directoryName) {
+Map _getPubspec(String directoryName) {
   var pubspecName = path.join(directoryName, 'pubspec.yaml');
   File pubspec = new File(pubspecName);
-  if (!pubspec.existsSync()) return '';
+  if (!pubspec.existsSync()) return {'name': ''};
   var contents = pubspec.readAsStringSync();
+  return loadYaml(contents);
+}
+
+/// Read a pubspec and return the library name, given a directory
+String packageNameFor(String directoryName) =>
+    _getPubspec(directoryName)['name'];
+
+/// Read a pubspec and return the library name, given a directory
+String _packageVersionFor(String directoryName) {
+  var spec = _getPubspec(directoryName);
+  return '${spec['name']}-${spec['version']}';
+}
+
+/// Look in the pubspec.lock to determine what version of a package we are
+/// documenting (null if not applicable).
+String packageVersion(LibraryMirror mirror) {
+  if (mirror.uri.scheme == 'file') {
+    String packageDirectory = getPackageDirectory(mirror);
+    if (packageDirectory == null) return '';

[Emily Fortuna, 2014/05/29 16:34:47]

This is the one line that was added from the previous CL:
https://codereview.chromium.org//288033010

+    if (packageDirectory.contains('.pub-cache')) {
+      return path.basename(packageDirectory);
+    }
+    String packageName = packageNameFor(packageDirectory);
+    return _packageVersionFor(packageDirectory);
+  } else if (mirror.uri.scheme == 'dart') {
+    // If this item is from the SDK, use what version of pub we're running to
+    // ascertain the SDK version.
+    var pubVersion = Process.runSync(pubScript, ['--version'],
+        runInShell: true);
+    if (pubVersion.exitCode != 0) {
+      print(pubVersion.stderr);
+    }
+    return pubVersion.stdout.replaceAll('Pub ', '').trim();
+  }
+  return '';
+}
+
+String _packageVersionHelper(String packageDirectory, String packageName) {
+  var publockName = path.join(packageDirectory, 'pubspec.lock');
+  File publock = new File(publockName);
+  if (!publock.existsSync()) return '';
+  var contents = publock.readAsStringSync();
   var spec = loadYaml(contents);
-  return spec["name"];
+  return spec['packages'][packageName];
 }
 
 /// Recursively walk up from directory name looking for a pubspec. Return
 /// the directory that contains it, or null if none is found.
 String _packageDirectoryFor(String directoryName) {
   var dir = directoryName;
   while (!_pubspecFor(dir).existsSync()) {
     var newDir = path.dirname(dir);
     if (newDir == dir) return null;
     dir = newDir;
   }
   return dir;
 }
 
 File _pubspecFor(String directoryName) =>
     new File(path.join(directoryName, 'pubspec.yaml'));