Use "pub list-package-dirs" to resolve package URIs in analysis server.

pkg/analysis_server/lib/src/package_map_provider.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 package.map.provider;
+
+import 'dart:convert';
+import 'dart:io' as io;
+
+import 'package:analysis_server/src/analysis_server.dart';
+import 'package:analysis_server/src/resource.dart';
+import 'package:analyzer/src/generated/engine.dart';
+
+/**
+ * A PackageMapProvider is an entity capable of determining the mapping from
+ * package name to source directory for a given folder.
+ */
+abstract class PackageMapProvider {
+  /**
+   * Compute a package map for the given folder, if possible.
+   *
+   * If a package map can't be computed, return null.
+   */
+  Map<String, Folder> computePackageMap(Folder folder);
+}
+
+/**
+ * Implementation of PackageMapProvider that operates by executing pub.
+ */
+class PubPackageMapProvider implements PackageMapProvider {
+  static const String PUB_LIST_COMMAND = 'list-package-dirs';
+
+  /**
+   * [ResourceProvider] that is used to create the [Folder]s that populate the
+   * package map.
+   */
+  final ResourceProvider resourceProvider;
+
+  PubPackageMapProvider(this.resourceProvider);
+
+  @override
+  Map<String, Folder> computePackageMap(Folder folder) {
+    // TODO(paulberry) make this asynchronous so that we can (a) do other
+    // analysis while it's in progress, and (b) time out if it takes too long
+    // to respond.
+    String executable = SHARED_SDK.pubExecutable.getAbsolutePath();
+    io.ProcessResult result;
+    try {
+      result = io.Process.runSync(
+          executable, [PUB_LIST_COMMAND], workingDirectory: folder.path);
+    } on io.ProcessException catch (exception, stackTrace) {
+      AnalysisEngine.instance.logger.logInformation(

[Brian Wilkerson, 2014/06/20 14:42:46]

These errors seems like something we should report back to the client so that
they can inform the user and/or correct the problem.

+          "Error running pub $PUB_LIST_COMMAND\n${exception}\n${stackTrace}");
+    }
+    if (result.exitCode != 0) {
+      AnalysisEngine.instance.logger.logInformation(
+          "pub $PUB_LIST_COMMAND failed: exit code ${result.exitCode}");
+      return null;
+    }
+    try {
+      return parsePackageMap(result.stdout);
+    } catch (exception, stackTrace) {
+      AnalysisEngine.instance.logger.logError(
+          "Malformed output from pub $PUB_LIST_COMMAND\n${exception}\n${stackTrace}");
+    }
+
+    return null;
+  }
+
+  /**
+   * Decode the JSON output from pub into a package map.
+   */
+  Map<String, Folder> parsePackageMap(String jsonText) {
+    // The output of pub looks like this:
+    // {
+    //   "packages": {
+    //     "foo": "path/to/foo",
+    //     "bar": ["path/to/bar1", "path/to/bar2"],
+    //     "myapp": "path/to/myapp",  // self link is included
+    //   },
+    //   "input_files": [
+    //     "path/to/myapp/pubspec.lock"
+    //   ]
+    // }
+    Map<String, Folder> packageMap = <String, Folder>{};
+    Map obj = JSON.decode(jsonText);
+    Map packages = obj['packages'];
+    packages.forEach((key, value) {
+      if (value is String) {
+        Resource resource = resourceProvider.getResource(value);
+        if (resource is Folder) {
+          packageMap[key] = resource;
+        }
+      } else if (value is List) {
+        // TODO(paulberry): support string lists.
+      }
+    });
+    return packageMap;
+  }
+}