DAS plugins: Launch a shared plugin, configured from analysis options

This change is the final piece in enabling plugins in the new style to
be launched from a specification in analysis options.

Work towards #53402

* We support both one legacy analyzer plugin (the current max), and
  a set of new analyzer plugins, which are combined and launched in one
  shared plugin isolate.
* Make PluginLocator.pluginMap private.
* Add a parameter to PluginManager.addPluginToContextRoot:
  isLegacyPlugin. This method is used for both legacy and new plugins,
  but has slightly different behavior, finding where the plugin files
  are.

Change-Id: I6644aecd4283eea22586ffd051a01b0ec8987fc5
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/395360
Reviewed-by: Brian Wilkerson <[email protected]>
Commit-Queue: Samuel Rawlins <[email protected]>

Author: srawlins

pkg/analysis_server/lib/src/plugin/plugin_locator.dart

@@ -21,7 +21,7 @@ class PluginLocator {
   /// The resource provider used to access the file system.
   final ResourceProvider resourceProvider;
 
-  final Map<String, String?> pluginMap = {};
+  final Map<String, String?> _pluginMap = {};
 
   /// Initialize a newly created plugin locator to use the given
   /// [resourceProvider] to access the file system.
@@ -36,18 +36,12 @@ class PluginLocator {
   ///
   /// The content of the plugin directory is not validated.
   String? findPlugin(String packageRoot) {
-    return pluginMap.putIfAbsent(packageRoot, () => _findPlugin(packageRoot));
-  }
-
-  /// The implementation of [findPlugin].
-  String? _findPlugin(String packageRoot) {
-    var packageFolder = resourceProvider.getFolder(packageRoot);
-    var pluginFolder = packageFolder
-        .getChildAssumingFolder(toolsFolderName)
-        .getChildAssumingFolder(defaultPluginFolderName);
-    if (pluginFolder.exists) {
-      return pluginFolder.path;
-    }
-    return null;
+    return _pluginMap.putIfAbsent(packageRoot, () {
+      var pluginFolder = resourceProvider
+          .getFolder(packageRoot)
+          .getChildAssumingFolder(toolsFolderName)
+          .getChildAssumingFolder(defaultPluginFolderName);
+      return pluginFolder.exists ? pluginFolder.path : null;
+    });
   }
 }

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

@@ -341,17 +341,20 @@ class PluginManager {
   ///
   /// If the plugin had not yet been started, then it will be started by this
   /// method.
+  ///
+  /// Specify whether this is a legacy plugin with [isLegacyPlugin].
   Future<void> addPluginToContextRoot(
     analyzer.ContextRoot contextRoot,
-    String path,
-  ) async {
+    String path, {
+    required bool isLegacyPlugin,
+  }) async {
     var plugin = _pluginMap[path];
     var isNew = false;
     if (plugin == null) {
       isNew = true;
       PluginFiles pluginFiles;
       try {
-        pluginFiles = filesFor(path);
+        pluginFiles = filesFor(path, isLegacyPlugin: isLegacyPlugin);
       } catch (exception, stackTrace) {
         plugin = DiscoveredPluginInfo(
           path,
@@ -464,10 +467,14 @@ class PluginManager {
 
   /// Returns the files associated with the plugin at the given [pluginPath].
   ///
+  /// In some cases, the plugin's sources are copied to a special directory. If
+  /// [pluginPath] does not include a `pubspec.yaml` file, we do not. If
+  /// [pluginPath] exists in a [BlazeWorkspace], we do not.
+  ///
   /// Throws a [PluginException] if there is a problem that prevents the plugin
   /// from being executing.
   @visibleForTesting
-  PluginFiles filesFor(String pluginPath) {
+  PluginFiles filesFor(String pluginPath, {required bool isLegacyPlugin}) {
     var pluginFolder = resourceProvider.getFolder(pluginPath);
     var pubspecFile = pluginFolder.getChildAssumingFile(file_paths.pubspecYaml);
     if (!pubspecFile.exists) {
@@ -482,16 +489,16 @@ class PluginManager {
       return _computeFiles(pluginFolder, workspace: workspace);
     }
 
+    if (!isLegacyPlugin) {
+      return _computeFiles(pluginFolder, pubCommand: 'upgrade');
+    }
+
     // Copy the plugin directory to a unique subdirectory of the plugin
     // manager's state location. The subdirectory's name is selected such that
     // it will be invariant across sessions, reducing the number of times we
     // copy the plugin contents, and the number of times we run `pub`.
-    var stateFolder = resourceProvider.getStateLocation('.plugin_manager');
-    if (stateFolder == null) {
-      throw PluginException('No state location, so plugin could not be copied');
-    }
-    var stateName = _uniqueDirectoryName(pluginPath);
-    var parentFolder = stateFolder.getChildAssumingFolder(stateName);
+
+    var parentFolder = pluginStateFolder(pluginPath);
     if (parentFolder.exists) {
       var executionFolder = parentFolder.getChildAssumingFolder(
         pluginFolder.shortName,
@@ -518,6 +525,19 @@ class PluginManager {
     return plugins;
   }
 
+  /// Returns the "plugin state" folder for a plugin at [pluginPath].
+  ///
+  /// This is a directory under the state location for '.plugin_manager', named
+  /// with a hash based on [pluginPath].
+  Folder pluginStateFolder(String pluginPath) {
+    var stateFolder = resourceProvider.getStateLocation('.plugin_manager');
+    if (stateFolder == null) {
+      throw PluginException('No state location, so plugin could not be copied');
+    }
+    var stateName = _uniqueDirectoryName(pluginPath);
+    return stateFolder.getChildAssumingFolder(stateName);
+  }
+
   /// The given [contextRoot] is no longer being analyzed.
   void removedContextRoot(analyzer.ContextRoot contextRoot) {
     var plugins = _pluginMap.values.toList();

pkg/analysis_server/lib/src/plugin/plugin_watcher.dart

@@ -6,10 +6,12 @@ import 'dart:convert';
 
 import 'package:analysis_server/src/plugin/plugin_locator.dart';
 import 'package:analysis_server/src/plugin/plugin_manager.dart';
+import 'package:analysis_server/src/plugin2/generator.dart';
 import 'package:analyzer/dart/analysis/context_root.dart';
 import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer/src/dart/analysis/driver.dart';
 import 'package:analyzer/src/dart/sdk/sdk.dart';
+import 'package:analyzer/src/util/file_paths.dart' as file_paths;
 
 /// An object that watches the results produced by analysis drivers to identify
 /// references to previously unseen packages and, if those packages have plugins
@@ -33,16 +35,18 @@ class PluginWatcher implements DriverWatcher {
   PluginWatcher(this.resourceProvider, this.manager)
     : _locator = PluginLocator(resourceProvider);
 
-  /// The context manager has just added the given analysis [driver]. This
-  /// method must be called before the driver has been allowed to perform any
-  /// analysis.
   @override
   void addedDriver(AnalysisDriver driver) {
     var contextRoot = driver.analysisContext!.contextRoot;
     _driverInfo[driver] = _DriverInfo(contextRoot, <String>[
       contextRoot.root.path,
       _getSdkPath(driver),
     ]);
+
+    // We temporarily support both "legacy plugins" and (new) "plugins." We
+    // restrict the number of legacy plugins to 1, for performance reasons.
+    // At some point, we will stop adding legacy plugins to the context root.
+
     for (var hostPackageName in driver.enabledLegacyPluginNames) {
       //
       // Determine whether the package exists and defines a plugin.
@@ -67,10 +71,36 @@ class PluginWatcher implements DriverWatcher {
       manager.addPluginToContextRoot(
         driver.analysisContext!.contextRoot,
         pluginPath,
+        isLegacyPlugin: true,
       );
     }
 
-    // TODO(srawlins): Generate package for plugin configurations, with PluginPackageGenerator.
+    // Now we add any specified (new) plugins to the context, as a single
+    // "legacy plugin" shared entrypoint.
+    var pluginConfigurations = driver.pluginConfigurations;
+    // Add a shared entrypoint plugin to the context root, only if one or more
+    // plugins are specified in analysis options.
+    if (pluginConfigurations.isNotEmpty) {
+      var contextRoot = driver.analysisContext!.contextRoot;
+      var packageGenerator = PluginPackageGenerator(pluginConfigurations);
+      // The path here just needs to be unique per context root.
+      var sharedPluginFolder = manager.pluginStateFolder(contextRoot.root.path)
+        ..create();
+      sharedPluginFolder
+          .getChildAssumingFile(file_paths.pubspecYaml)
+          .writeAsStringSync(packageGenerator.generatePubspec());
+      var libFolder = sharedPluginFolder.getChildAssumingFolder('bin')
+        ..create();
+      libFolder
+          .getChildAssumingFile('plugin.dart')
+          .writeAsStringSync(packageGenerator.generateEntrypoint());
+
+      manager.addPluginToContextRoot(
+        contextRoot,
+        sharedPluginFolder.path,
+        isLegacyPlugin: false,
+      );
+    }
   }
 
   /// The context manager has just removed the given analysis [driver].

pkg/analysis_server/lib/src/plugin2/analyzer_version.g.dart

@@ -7,6 +7,10 @@
 // Instead, run 'dart pkg/analysis_server/tool/generate_analyzer_version.dart'
 // to update this file.
 
-/// The version of the analyzer that matches the analyzer code used by the
-/// analysis_server package.
-var analyzerVersion = '7.0.0-dev';
+/// The version of the analyzer_plugin package that matches the analyzer_plugin
+/// code used by the analysis_server package.
+var analyzerPluginVersion = '0.12.0';
+
+/// The version of the analyzer package that matches the analyzer code used by
+/// the analysis_server package.
+var analyzerVersion = '7.0.0';

pkg/analysis_server/lib/src/plugin2/generator.dart

@@ -22,12 +22,12 @@ class PluginPackageGenerator {
     var imports = [
       "'package:analysis_server_plugin/src/plugin_server.dart'",
       "'package:analyzer/file_system/physical_file_system.dart'",
-      "'package:analyzer_plugin/starter.dart'",
+      "'package:analyzer_plugin/src/channel/isolate_channel.dart'",
       for (var configuration in _pluginConfigurations)
         "'package:${configuration.name}/main.dart' as ${configuration.name}",
     ];
 
-    var buffer = StringBuffer("import 'dart:isolate';");
+    var buffer = StringBuffer("import 'dart:isolate';\n");
     for (var import in imports..sort()) {
       buffer.writeln('import $import;');
     }
@@ -45,8 +45,9 @@ Future<void> main(List<String> args, SendPort sendPort) async {
     buffer.write('''
     ],
   );
-  await startPlugin();
-  ServerPluginStarter(wrangler).start(sendPort);
+  await pluginServer.initialize();
+  var channel = PluginIsolateChannel(sendPort);
+  pluginServer.start(channel);
 }
 ''');
 
@@ -62,6 +63,7 @@ name: plugin_entrypoint
 version: 0.0.1
 dependencies:
   analyzer: '$analyzerVersion'
+  analyzer_plugin: '$analyzerPluginVersion'
 ''');
 
     for (var configuration in _pluginConfigurations) {

pkg/analysis_server/lib/src/utilities/mocks.dart

@@ -164,8 +164,9 @@ class TestPluginManager implements PluginManager {
   @override
   Future<void> addPluginToContextRoot(
     analyzer.ContextRoot contextRoot,
-    String path,
-  ) async {
+    String path, {
+    required bool isLegacyPlugin,
+  }) async {
     contextRootPlugins.putIfAbsent(contextRoot, () => []).add(path);
   }