DAS plugins: Wire up priority files

This is super awkward. I had "added support" in f27e78af6b20 but it was really just internal wiring. I honestly do not remember what I was thinking or why I landed that CL incomplete.

Change-Id: Iad6800e11df189879acad4d189d6f8c68ee673f4
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/449602
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
Commit-Queue: Samuel Rawlins <srawlins@google.com>

Author: srawlins

pkg/analysis_server_plugin/CHANGELOG.md

@@ -5,6 +5,9 @@
 - Add support for automatic re-analysis of files changed on-disk (as opposed to
   file contents changed in the IDE, which is already supported).
 - Add support for analyzing and reporting diagnostics in part files.
+- Add support for `RuleContext.isInLibDir` and `RuleContext.package`.
+- Add support for priority files in an IDE.
+- Correct the text range over which fixes are calculated.
 - Breaking change: a `Plugin` class must now implement `String get name`.
 
 ## 0.2.2

pkg/analysis_server_plugin/lib/src/plugin_server.dart

@@ -43,6 +43,7 @@ import 'package:analyzer_plugin/protocol/protocol_common.dart' as protocol;
 import 'package:analyzer_plugin/protocol/protocol_constants.dart' as protocol;
 import 'package:analyzer_plugin/protocol/protocol_generated.dart' as protocol;
 import 'package:analyzer_plugin/src/protocol/protocol_internal.dart';
+import 'package:meta/meta.dart';
 
 /// A pair, matching a [Diagnostic] with it's equivalent
 /// [protocol.AnalysisError].
@@ -101,6 +102,9 @@ class PluginServer {
     PluginRegistryImpl.registerIgnoreProducerGenerators();
   }
 
+  @visibleForTesting
+  Set<String> get priorityPaths => {..._priorityPaths};
+
   /// Handles an 'analysis.setPriorityFiles' request.
   ///
   /// Throws a [RequestFailure] if the request could not be handled.
@@ -561,8 +565,10 @@ class PluginServer {
         result = await _handleAnalysisSetContextRoots(params);
 
       case protocol.ANALYSIS_REQUEST_SET_PRIORITY_FILES:
-        // TODO(srawlins): Support!
-        result = null;
+        var params = protocol.AnalysisSetPriorityFilesParams.fromRequest(
+          request,
+        );
+        result = await handleAnalysisSetPriorityFiles(params);
 
       case protocol.ANALYSIS_REQUEST_UPDATE_CONTENT:
         var params = protocol.AnalysisUpdateContentParams.fromRequest(request);

pkg/analysis_server_plugin/test/src/plugin_server_test.dart

@@ -306,6 +306,41 @@ bool b = false;
     expect(params.errors, isEmpty);
   }
 
+  Future<void> test_setPriorityFiles() async {
+    newFile(filePath, '''
+int a = 0;
+''');
+    newFile(file2Path, '''
+int b = 1;
+''');
+    await channel.sendRequest(
+      protocol.AnalysisSetContextRootsParams([contextRoot]),
+    );
+
+    var paramsQueue = _analysisErrorsParams;
+    var params = await paramsQueue.next;
+    expect(params.file, filePath);
+
+    params = await paramsQueue.next;
+    expect(params.file, file2Path);
+
+    await channel.sendRequest(
+      protocol.AnalysisSetPriorityFilesParams([file2Path]),
+    );
+
+    expect(pluginServer.priorityPaths, {file2Path});
+
+    await channel.sendRequest(
+      protocol.AnalysisSetContextRootsParams([contextRoot]),
+    );
+
+    params = await paramsQueue.next;
+    expect(params.file, file2Path);
+
+    params = await paramsQueue.next;
+    expect(params.file, filePath);
+  }
+
   Future<void> test_unsupportedRequest() async {
     writeAnalysisOptionsWithPlugin();
     newFile(filePath, 'bool b = false;');