`analyzer_cli` move to SDK.

pkg/analyzer_cli/lib/src/plugin/plugin_manager.dart

+// Copyright (c) 2015, 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 analyzer_cli.src.plugin.plugin_manager;
+
+import 'dart:io';
+
+import 'package:analyzer/src/plugin/plugin_configuration.dart';
+import 'package:path/path.dart' as path;
+
+const _manifestFileName = 'plugins.yaml';
+
+/// Given a local configuration (as defined in `.analysis_options`)
+/// and information from a plugin manifest, return plugin info
+/// appropriate for configuring this plugin.
+PluginInfo combine(PluginInfo localConfig, PluginInfo manifestInfo) {
+  return new PluginInfo(
+      name: localConfig.name,
+      version: manifestInfo.version,
+      className: manifestInfo.className,
+      libraryUri: manifestInfo.libraryUri);
+}
+
+/// Call-back to allow for the injection of manifest readers that do not need
+/// to go to disk (for testing purposes).
+typedef String ManifestReader(Uri uri);
+
+/// Wraps a [plugin] info object elaborated with any configuration information
+/// extracted from an associated manifest and [status].
+class PluginDetails {
+  /// Plugin status.
+  final PluginStatus status;
+
+  /// Plugin info.
+  final PluginInfo plugin;
+
+  /// Wrap a [plugin] with [status] info.
+  PluginDetails(this.plugin) : status = PluginStatus.Applicable;
+  PluginDetails.notApplicable(this.plugin)
+      : status = PluginStatus.NotApplicable;
+  PluginDetails.notFound(this.plugin) : status = PluginStatus.NotFound;
+}
+
+/// Manages plugin information derived from plugin manifests.
+class PluginManager {
+  /// Mapping from package name to package location.
+  final Map<String, Uri> _packageMap;
+
+  /// The package naming the app to host plugins.
+  final String hostPackage;
+
+  /// Function to perform the reading of manifest URIs. (For testing.)
+  ManifestReader _manifestReader;
+
+  /// Create a plugin manager with backing package map information.
+  PluginManager(this._packageMap, this.hostPackage,
+      [ManifestReader manifestReader]) {
+    _manifestReader =
+        manifestReader != null ? manifestReader : _findAndReadManifestAtUri;
+  }
+
+  /// Find a plugin manifest describing the given [pluginPackage].
+  PluginManifest findManifest(String pluginPackage) {
+    Uri uri = _packageMap[pluginPackage];
+    String contents = _manifestReader(uri);
+    if (contents == null) {
+      return null;
+    }
+    return parsePluginManifestString(contents);
+  }
+
+  /// Return [PluginDetails] derived from associated plugin manifests
+  /// corresponding to plugins specified in the given [config].
+  Iterable<PluginDetails> getPluginDetails(PluginConfig config) =>
+      config.plugins.map((PluginInfo localConfig) {
+        PluginManifest manifest = findManifest(localConfig.name);
+        return _getDetails(localConfig, manifest);
+      });
+
+  String _findAndReadManifestAtUri(Uri uri) {
+    File manifestFile = _findManifest(uri);
+    return manifestFile?.readAsStringSync();
+  }
+
+  File _findManifest(Uri uri) {
+    if (uri == null) {
+      return null;
+    }
+
+    Directory directory = new Directory.fromUri(uri);
+    File file = new File(path.join(directory.path, _manifestFileName));
+
+    return file.existsSync() ? file : null;
+  }
+
+  PluginDetails _getDetails(PluginInfo localConfig, PluginManifest manifest) {
+    if (manifest == null) {
+      return new PluginDetails.notFound(localConfig);
+    }
+    if (!manifest.contributesTo.contains(hostPackage)) {
+      return new PluginDetails.notApplicable(localConfig);
+    }
+
+    return new PluginDetails(combine(localConfig, manifest.plugin));
+  }
+}
+
+/// Describes plugin status.
+enum PluginStatus { Applicable, NotApplicable, NotFound }