Fix the handling of LSP headers

The invalid handling of LSP headers caused the analysis server, in LSP
mode, to not recognize any of the messages being sent to it.

Change-Id: I03b3c8e22216f3451401823dd62a49a984edc550
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/464626
Commit-Queue: Brian Wilkerson <[email protected]>
Reviewed-by: Keerti Parthasarathy <[email protected]>

Author: bwilkerson

pkg/analysis_server/tool/log_player/log_player.dart

@@ -6,6 +6,7 @@ import 'package:analysis_server/src/server/driver.dart';
 import 'package:analysis_server/src/session_logger/entry_kind.dart';
 import 'package:analysis_server/src/session_logger/log_entry.dart';
 import 'package:analysis_server/src/session_logger/process_id.dart';
+import 'package:collection/collection.dart';
 
 import 'log.dart';
 import 'server_driver.dart';
@@ -48,6 +49,10 @@ class LogPlayer {
               'Analysis server already started, only one instance is allowed.',
             );
           }
+          // TODO(brianwilkerson): Stop parsing out the protocol. Instead,
+          //  consider verifying that a protocol was specified, throwing if not,
+          //  and then just pass all of the arguments to the constructor. This
+          //  would require allow-listing the protocol option.
           var parsedArgs = driverArgParser.parse(entry.argList);
           var protocolOption = parsedArgs.option(Driver.serverProtocolOption);
           var protocol = switch (protocolOption) {
@@ -56,7 +61,12 @@ class LogPlayer {
             _ => throw StateError('Unrecognized protocol $protocolOption'),
           };
           var server = this.server = ServerDriver(protocol: protocol);
-          server.additionalArguments.addAll(entry.argList);
+          server.additionalArguments.addAll(
+            entry.argList.whereNot(
+              (element) =>
+                  element.startsWith('--${Driver.serverProtocolOption}'),
+            ),
+          );
           await server.start();
         case EntryKind.message:
           if (entry.receiver == ProcessId.server) {
@@ -65,7 +75,7 @@ class LogPlayer {
             _handleMessageFromServer(entry);
           } else {
             throw StateError('''
-Unexpected sender/reciever for message:
+Unexpected sender/receiver for message:
 
 sender: ${entry.sender}
 receiver: ${entry.receiver}
@@ -74,12 +84,14 @@ receiver: ${entry.receiver}
       }
       nextIndex++;
     }
+    await _readMessagesFromServer();
     if (!_hasSeenShutdown) {
       server?.shutdown();
     }
     if (!_hasSeenExit) {
       server?.exit();
     }
+    await _readMessagesFromServer();
     server = null;
   }
 
@@ -112,6 +124,12 @@ receiver: ${entry.receiver}
     }
   }
 
+  /// Wait for the server to process any messages that it may have received and
+  /// for any responses to be sent back.
+  Future<void> _readMessagesFromServer() async {
+    await Future.delayed(const Duration(seconds: 1));
+  }
+
   /// Sends the message in the [entry] to the server.
   Future<void> _sendMessageToServer(LogEntry entry) async {
     var server = this.server;

pkg/analysis_server/tool/log_player/server_driver.dart

@@ -6,6 +6,7 @@ import 'dart:convert';
 import 'dart:io';
 
 import 'package:analysis_server/lsp_protocol/protocol.dart' show jsonRpcVersion;
+import 'package:analysis_server/src/lsp/lsp_packet_transformer.dart';
 import 'package:analysis_server/src/server/driver.dart';
 import 'package:analysis_server/src/session_logger/log_entry.dart';
 
@@ -109,7 +110,20 @@ class ServerDriver {
   /// used by the IDE.
   void sendMessageFromIde(Message message) {
     if (_stdinSink case IOSink writeSink) {
-      writeSink.writeln(json.encode(message));
+      var jsonEncodedBody = jsonEncode(message);
+      if (_protocol == ServerProtocol.lsp) {
+        var utf8EncodedBody = utf8.encode(jsonEncodedBody);
+        var header =
+            'Content-Length: ${utf8EncodedBody.length}\r\n'
+            'Content-Type: application/vscode-jsonrpc; charset=utf-8\r\n\r\n';
+        var asciiEncodedHeader = ascii.encode(header);
+
+        // Header is always ascii, body is always utf8!
+        writeSink.add(asciiEncodedHeader);
+        writeSink.add(utf8EncodedBody);
+      } else {
+        writeSink.write(jsonEncodedBody);
+      }
     } else {
       throw StateError(
         "The method 'start' must be invoked before "
@@ -164,10 +178,16 @@ class ServerDriver {
       ...filteredAdditionalArguments,
     ]);
     _stdinSink = process.stdin;
-    process.stdout
-        .transform(const Utf8Decoder())
-        .transform(const LineSplitter())
-        .listen(_receiveMessageFromServer);
+    if (_protocol == ServerProtocol.lsp) {
+      process.stdout
+          .transform(LspPacketTransformer())
+          .listen(_receiveMessageFromServer);
+    } else {
+      process.stdout
+          .transform(const Utf8Decoder())
+          .transform(const LineSplitter())
+          .listen(_receiveMessageFromServer);
+    }
   }
 
   void _receiveMessageFromServer(String message) {