[ package:dds ] Handle expression evaluation invocations in DDS and forward compileExpression calls to clients which provide their own compilation service.

Change-Id: I2daec26929ad4f530d28d0073a0b2758850bec0a
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/150694
Reviewed-by: Ryan Macnak <rmacnak@google.com>
Commit-Queue: Ben Konyi <bkonyi@google.com>

pkg/dds/CHANGELOG.md

@@ -1,6 +1,11 @@
+# 1.2.1
+
+- Fixed issue where `evaluate` and `evaluateInFrame` were not invoking client
+  provided implementations of `compileExpression`.
+
 # 1.2.0
 
-- Fix issue where forwarding requests with no RPC parameters would return an
+- Fixed issue where forwarding requests with no RPC parameters would return an
   RPC error.
 
 # 1.1.0

pkg/dds/lib/dds.dart

@@ -29,6 +29,7 @@ part 'src/client.dart';
 part 'src/client_manager.dart';
 part 'src/constants.dart';
 part 'src/dds_impl.dart';
+part 'src/expression_evaluator.dart';
 part 'src/logging_repository.dart';
 part 'src/isolate_manager.dart';
 part 'src/named_lookup.dart';

pkg/dds/lib/src/client.dart

@@ -157,6 +157,19 @@ class _DartDevelopmentServiceClient {
       return supportedProtocols;
     });
 
+    // `evaluate` and `evaluateInFrame` actually consist of multiple RPC
+    // invocations, including a call to `compileExpression` which can be
+    // overridden by clients which provide their own implementation (e.g.,
+    // Flutter Tools). We handle all of this in [_ExpressionEvaluator].
+    _clientPeer.registerMethod(
+      'evaluate',
+      dds.expressionEvaluator.execute,
+    );
+    _clientPeer.registerMethod(
+      'evaluateInFrame',
+      dds.expressionEvaluator.execute,
+    );
+
     // When invoked within a fallback, the next fallback will start executing.
     // The final fallback forwards the request to the VM service directly.
     @alwaysThrows

pkg/dds/lib/src/client_manager.dart

@@ -133,6 +133,16 @@ class _ClientManager {
     }
   }
 
+  _DartDevelopmentServiceClient findFirstClientThatHandlesService(
+      String service) {
+    for (final client in clients) {
+      if (client.services.containsKey(service)) {
+        return client;
+      }
+    }
+    return null;
+  }
+
   // Handles namespace generation for service extensions.
   static const _kServicePrologue = 's';
   final NamedLookup<_DartDevelopmentServiceClient> clients = NamedLookup(

pkg/dds/lib/src/dds_impl.dart

@@ -11,6 +11,7 @@ class _DartDevelopmentService implements DartDevelopmentService {
     this._authCodesEnabled,
   ) {
     _clientManager = _ClientManager(this);
+    _expressionEvaluator = _ExpressionEvaluator(this);
     _isolateManager = _IsolateManager(this);
     _loggingRepository = _LoggingRepository();
     _streamManager = _StreamManager(this);
@@ -197,6 +198,9 @@ class _DartDevelopmentService implements DartDevelopmentService {
   _ClientManager get clientManager => _clientManager;
   _ClientManager _clientManager;
 
+  _ExpressionEvaluator get expressionEvaluator => _expressionEvaluator;
+  _ExpressionEvaluator _expressionEvaluator;
+
   _IsolateManager get isolateManager => _isolateManager;
   _IsolateManager _isolateManager;
 

pkg/dds/lib/src/expression_evaluator.dart

@@ -0,0 +1,128 @@
+// Copyright (c) 2020, 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.
+
+part of dds;
+
+/// A helper class which handles `evaluate` and `evaluateInFrame` calls by
+/// potentially forwarding compilation requests to an external compilation
+/// service like Flutter Tools.
+class _ExpressionEvaluator {
+  _ExpressionEvaluator(this.dds);
+
+  Future<Map<String, dynamic>> execute(json_rpc.Parameters parameters) async {
+    final isolateId = parameters['isolateId'].asString;
+    final expression = parameters['expression'].asString;
+    Map<String, dynamic> buildScopeResponse;
+
+    try {
+      buildScopeResponse = await _buildScope(parameters);
+    } on json_rpc.RpcException catch (e) {
+      throw _RpcErrorCodes.buildRpcException(
+        _RpcErrorCodes.kExpressionCompilationError,
+        data: e.data,
+      );
+    }
+    String kernelBase64;
+    try {
+      kernelBase64 =
+          await _compileExpression(isolateId, expression, buildScopeResponse);
+    } on json_rpc.RpcException catch (e) {
+      throw _RpcErrorCodes.buildRpcException(
+        _RpcErrorCodes.kExpressionCompilationError,
+        data: e.data,
+      );
+    }
+    return await _evaluateCompiledExpression(
+        parameters, isolateId, kernelBase64);
+  }
+
+  Future<Map<String, dynamic>> _buildScope(
+      json_rpc.Parameters parameters) async {
+    final params = _setupParams(parameters);
+    params['isolateId'] = parameters['isolateId'].asString;
+    if (parameters['scope'].asMapOr(null) != null) {
+      params['scope'] = parameters['scope'].asMap;
+    }
+    return await dds._vmServiceClient.sendRequest(
+      '_buildExpressionEvaluationScope',
+      params,
+    );
+  }
+
+  Future<String> _compileExpression(String isolateId, String expression,
+      Map<String, dynamic> buildScopeResponseResult) async {
+    _DartDevelopmentServiceClient externalClient =
+        dds.clientManager.findFirstClientThatHandlesService(
+      'compileExpression',
+    );
+
+    final compileParams = <String, dynamic>{
+      'isolateId': isolateId,
+      'expression': expression,
+      'definitions': buildScopeResponseResult['param_names'],
+      'typeDefinitions': buildScopeResponseResult['type_params_names'],
+      'libraryUri': buildScopeResponseResult['libraryUri'],
+      'isStatic': buildScopeResponseResult['isStatic'],
+    };
+
+    final klass = buildScopeResponseResult['klass'];
+    if (klass != null) {
+      compileParams['klass'] = klass;
+    }
+    // TODO(bkonyi): handle service disappeared case?
+    try {
+      if (externalClient != null) {
+        return (await externalClient.sendRequest(
+          'compileExpression',
+          compileParams,
+        ))['result']['kernelBytes'];
+      } else {
+        // Fallback to compiling using the kernel service.
+        return (await dds._vmServiceClient.sendRequest(
+          '_compileExpression',
+          compileParams,
+        ))['kernelBytes'];
+      }
+    } on json_rpc.RpcException catch (e) {
+      throw _RpcErrorCodes.buildRpcException(
+        _RpcErrorCodes.kExpressionCompilationError,
+        data: e.data,
+      );
+    }
+  }
+
+  Future<Map<String, dynamic>> _evaluateCompiledExpression(
+    json_rpc.Parameters parameters,
+    String isolateId,
+    String kernelBase64,
+  ) async {
+    final params = _setupParams(parameters);
+    params['isolateId'] = isolateId;
+    params['kernelBytes'] = kernelBase64;
+    params['disableBreakpoints'] =
+        parameters['disableBreakpoints'].asBoolOr(false);
+    if (parameters['scope'].asMapOr(null) != null) {
+      params['scope'] = parameters['scope'].asMap;
+    }
+    return await dds._vmServiceClient.sendRequest(
+      '_evaluateCompiledExpression',
+      params,
+    );
+  }
+
+  Map<String, dynamic> _setupParams(json_rpc.Parameters parameters) {
+    if (parameters.method == 'evaluateInFrame') {
+      return <String, dynamic>{
+        'frameIndex': parameters['frameIndex'].asInt,
+      };
+    } else {
+      assert(parameters.method == 'evaluate');
+      return <String, dynamic>{
+        'targetId': parameters['targetId'].asString,
+      };
+    }
+  }
+
+  final _DartDevelopmentService dds;
+}

pkg/dds/lib/src/rpc_error_codes.dart

@@ -5,10 +5,11 @@
 part of dds;
 
 abstract class _RpcErrorCodes {
-  static json_rpc.RpcException buildRpcException(int code) {
+  static json_rpc.RpcException buildRpcException(int code, {dynamic data}) {
     return json_rpc.RpcException(
       code,
       errorMessages[code],
+      data: data,
     );
   }
 
@@ -34,7 +35,7 @@ abstract class _RpcErrorCodes {
   // static const kIsolateMustHaveReloaded = 110;
   static const kServiceAlreadyRegistered = 111;
   static const kServiceDisappeared = 112;
-  // static const kExpressionCompilationError = 113;
+  static const kExpressionCompilationError = 113;
   // static const kInvalidTimelineRequest = 114;
 
   // Experimental (used in private rpcs).
@@ -48,5 +49,6 @@ abstract class _RpcErrorCodes {
     kStreamNotSubscribed: 'Stream not subscribed',
     kServiceAlreadyRegistered: 'Service already registered',
     kServiceDisappeared: 'Service has disappeared',
+    kExpressionCompilationError: 'Expression compilation error',
   };
 }

pkg/dds/pubspec.yaml

@@ -3,7 +3,7 @@ description: >-
   A library used to spawn the Dart Developer Service, used to communicate with
   a Dart VM Service instance.
 
-version: 1.2.0
+version: 1.2.1
 
 homepage: https://github.com/dart-lang/sdk/tree/master/pkg/dds
 

runtime/observatory/tests/service/string_escaping_test.dart

@@ -65,7 +65,6 @@ Future testStrings(Isolate isolate) async {
   expectTruncatedString(String varName, String varValueAsString) {
     Field field = lib.variables.singleWhere((v) => v.name == varName);
     Instance value = field.staticValue;
-    print(value.valueAsString);
     expect(varValueAsString, startsWith(value.valueAsString));
     expect(value.valueAsStringIsTruncated, isTrue);
   }

runtime/vm/json_stream.cc

@@ -174,7 +174,6 @@ void JSONStream::PrintError(intptr_t code, const char* details_format, ...) {
       va_start(args2, details_format);
       Utils::VSNPrint(buffer, (len + 1), details_format, args2);
       va_end(args2);
-
       data.AddProperty("details", buffer);
     }
   }

runtime/vm/json_stream.h

@@ -38,6 +38,7 @@ class Zone;
 //
 //  - runtime/vm/service/vmservice.dart
 //  - runtime/observatory/lib/src/service/object.dart
+//  - pkg/dds/lib/src/rpc_error_codes.dart
 //
 enum JSONRpcErrorCode {
   kParseError = -32700,

sdk_nnbd/lib/_internal/vm/bin/vmservice_server.dart

@@ -362,7 +362,7 @@ class Server {
         });
       } else {
         // Forward the websocket connection request to DDS.
-        request.response.redirect(_service.ddsUri);
+        request.response.redirect(_service.ddsUri!);
       }
       return;
     }

sdk_nnbd/lib/vmservice/running_isolates.dart

@@ -75,6 +75,14 @@ class _Evaluator {
   _Evaluator(this._message, this._isolate, this._service);
 
   Future<Response> run() async {
+    if (_service.ddsUri != null) {
+      return Response.from(encodeRpcError(
+        _message,
+        kInternalError,
+        details: 'Fell through to VM Service expression evaluation when a DDS '
+            'instance was connected. Please file an issue on GitHub.',
+      ));
+    }
     final buildScopeResponse = await _buildScope();
     final responseJson = buildScopeResponse.decodeJson();
 

sdk_nnbd/lib/vmservice/vmservice.dart

@@ -47,7 +47,7 @@ final serviceAuthToken = _makeAuthToken();
 final isolateEmbedderData = <int, IsolateEmbedderData>{};
 
 // These must be kept in sync with the declarations in vm/json_stream.h and
-// pkg/dds/lib/src/stream_manager.dart.
+// pkg/dds/lib/src/rpc_error_codes.dart.
 const kParseError = -32700;
 const kInvalidRequest = -32600;
 const kMethodNotFound = -32601;
@@ -219,7 +219,7 @@ class VMService extends MessageRouter {
 
   final devfs = DevFS();
 
-  Uri get ddsUri => _ddsUri!;
+  Uri? get ddsUri => _ddsUri;
   Uri? _ddsUri;
 
   Future<String> _yieldControlToDDS(Message message) async {