Finish modifying analysis server to make use of code generation.

pkg/analysis_server/lib/src/protocol.dart

Index: pkg/analysis_server/lib/src/protocol.dart
diff --git a/pkg/analysis_server/lib/src/protocol.dart b/pkg/analysis_server/lib/src/protocol.dart
index b30dc5aba844633cab801205c39ece92fc2f6b2c..d4d3536bb127733ca513653d711ce1f5020fcbc0 100644
--- a/pkg/analysis_server/lib/src/protocol.dart
+++ b/pkg/analysis_server/lib/src/protocol.dart
@@ -5,9 +5,611 @@
 library protocol;
 
 import 'dart:collection';
-import 'dart:convert' show JsonDecoder;
+import 'dart:convert';
+
+import 'package:analysis_server/src/computer/element.dart' show
+    elementFromEngine;
+import 'package:analysis_server/src/search/search_result.dart' show
+    searchResultFromMatch;
+import 'package:analysis_server/src/services/correction/fix.dart' show Fix;
+import 'package:analysis_server/src/services/search/search_engine.dart' as
+    engine;
+import 'package:analyzer/src/generated/ast.dart' as engine;
+import 'package:analyzer/src/generated/element.dart' as engine;
+import 'package:analyzer/src/generated/engine.dart' as engine;
+import 'package:analyzer/src/generated/error.dart' as engine;
+import 'package:analyzer/src/generated/source.dart' as engine;
+
+part 'generated_protocol.dart';
+
+/**
+ * Translate the input [map], applying [keyCallback] to all its keys, and
+ * [valueCallback] to all its values.
+ */
+mapMap(Map map, {dynamic keyCallback(key), dynamic valueCallback(value)}) {
+  Map result = {};
+  map.forEach((key, value) {
+    if (keyCallback != null) {
+      key = keyCallback(key);
+    }
+    if (valueCallback != null) {
+      value = valueCallback(value);
+    }
+    result[key] = value;
+  });
+  return result;
+}
+
+/**
+ * Adds the given [sourceEdits] to the list in [sourceFileEdit].
+ */
+void _addAllEditsForSource(SourceFileEdit sourceFileEdit,
+    Iterable<SourceEdit> edits) {
+  edits.forEach(sourceFileEdit.add);
+}
+
+/**
+ * Adds the given [sourceEdit] to the list in [sourceFileEdit].
+ */
+void _addEditForSource(SourceFileEdit sourceFileEdit, SourceEdit sourceEdit) {
+  List<SourceEdit> edits = sourceFileEdit.edits;
+  int index = 0;
+  while (index < edits.length && edits[index].offset > sourceEdit.offset) {
+    index++;
+  }
+  edits.insert(index, sourceEdit);
+}
+
+/**
+ * Adds [edit] to the [FileEdit] for the given [file].
+ */
+void _addEditToSourceChange(SourceChange change, String file, SourceEdit edit) {
+  SourceFileEdit fileEdit = change.getFileEdit(file);
+  if (fileEdit == null) {
+    fileEdit = new SourceFileEdit(file);
+    change.addFileEdit(fileEdit);
+  }
+  fileEdit.add(edit);
+}
+
+/**
+ * Create an AnalysisError based on error information from the analyzer
+ * engine.  Access via AnalysisError.fromEngine().
+ */
+AnalysisError _analysisErrorFromEngine(engine.LineInfo lineInfo,
+    engine.AnalysisError error) {
+  engine.ErrorCode errorCode = error.errorCode;
+  // prepare location
+  Location location;
+  {
+    String file = error.source.fullName;
+    int offset = error.offset;
+    int length = error.length;
+    int startLine = -1;
+    int startColumn = -1;
+    if (lineInfo != null) {
+      engine.LineInfo_Location lineLocation = lineInfo.getLocation(offset);
+      if (lineLocation != null) {
+        startLine = lineLocation.lineNumber;
+        startColumn = lineLocation.columnNumber;
+      }
+    }
+    location = new Location(file, offset, length, startLine, startColumn);
+  }
+  // done
+  var severity = new ErrorSeverity(errorCode.errorSeverity.name);
+  var type = new ErrorType(errorCode.type.name);
+  String message = error.message;
+  String correction = error.correction;
+  return new AnalysisError(
+      severity,
+      type,
+      location,
+      message,
+      correction: correction);
+}
+
+/**
+ * Returns a list of AnalysisErrors correponding to the given list of Engine
+ * errors.  Access via AnalysisError.listFromEngine().
+ */
+List<AnalysisError> _analysisErrorListFromEngine(engine.LineInfo lineInfo,
+    List<engine.AnalysisError> errors) {
+  return errors.map((engine.AnalysisError error) {
+    return new AnalysisError.fromEngine(lineInfo, error);
+  }).toList();
+}
+
+/**
+ * Get the result of applying the edit to the given [code].  Access via
+ * SourceEdit.apply().
+ */
+String _applyEdit(String code, SourceEdit edit) {
+  return code.substring(0, edit.offset) +
+      edit.replacement +
+      code.substring(edit.end);
+}
+
+/**
+ * Get the result of applying a set of [edits] to the given [code].  Edits
+ * are applied in the order they appear in [edits].  Access via
+ * SourceEdit.applySequence().
+ */
+String _applySequence(String code, Iterable<SourceEdit> edits) {
+  edits.forEach((SourceEdit edit) {
+    code = edit.apply(code);
+  });
+  return code;
+}
+
+/**
+ * Map an element kind from the analyzer engine to a [CompletionSuggestionKind].
+ */
+CompletionSuggestionKind _completionSuggestionKindFromElementKind(engine.ElementKind kind) {
+  //    ElementKind.ANGULAR_FORMATTER,
+  //    ElementKind.ANGULAR_COMPONENT,
+  //    ElementKind.ANGULAR_CONTROLLER,
+  //    ElementKind.ANGULAR_DIRECTIVE,
+  //    ElementKind.ANGULAR_PROPERTY,
+  //    ElementKind.ANGULAR_SCOPE_PROPERTY,
+  //    ElementKind.ANGULAR_SELECTOR,
+  //    ElementKind.ANGULAR_VIEW,
+  if (kind == engine.ElementKind.CLASS) return CompletionSuggestionKind.CLASS;
+  //    ElementKind.COMPILATION_UNIT,
+  if (kind == engine.ElementKind.CONSTRUCTOR) return CompletionSuggestionKind.CONSTRUCTOR;
+  //    ElementKind.DYNAMIC,
+  //    ElementKind.EMBEDDED_HTML_SCRIPT,
+  //    ElementKind.ERROR,
+  //    ElementKind.EXPORT,
+  //    ElementKind.EXTERNAL_HTML_SCRIPT,
+  if (kind == engine.ElementKind.FIELD) return CompletionSuggestionKind.FIELD;
+  if (kind == engine.ElementKind.FUNCTION) return CompletionSuggestionKind.FUNCTION;
+  if (kind == engine.ElementKind.FUNCTION_TYPE_ALIAS) return CompletionSuggestionKind.FUNCTION_TYPE_ALIAS;
+  if (kind == engine.ElementKind.GETTER) return CompletionSuggestionKind.GETTER;
+  //    ElementKind.HTML,
+  if (kind == engine.ElementKind.IMPORT) return CompletionSuggestionKind.IMPORT;
+  //    ElementKind.LABEL,
+  //    ElementKind.LIBRARY,
+  if (kind == engine.ElementKind.LOCAL_VARIABLE) return CompletionSuggestionKind.LOCAL_VARIABLE;
+  if (kind == engine.ElementKind.METHOD) return CompletionSuggestionKind.METHOD;
+  //    ElementKind.NAME,
+  if (kind == engine.ElementKind.PARAMETER) return CompletionSuggestionKind.PARAMETER;
+  //    ElementKind.POLYMER_ATTRIBUTE,
+  //    ElementKind.POLYMER_TAG_DART,
+  //    ElementKind.POLYMER_TAG_HTML,
+  //    ElementKind.PREFIX,
+  if (kind == engine.ElementKind.SETTER) return CompletionSuggestionKind.SETTER;
+  if (kind == engine.ElementKind.TOP_LEVEL_VARIABLE) return CompletionSuggestionKind.TOP_LEVEL_VARIABLE;
+  //    ElementKind.TYPE_PARAMETER,
+  //    ElementKind.UNIVERSE
+  throw new ArgumentError('Unknown CompletionSuggestionKind for: $kind');
+}
+
+/**
+ * Create an ElementKind based on a value from the analyzer engine.  Access
+ * this function via new ElementKind.fromEngine().
+ */
+ElementKind _elementKindFromEngine(engine.ElementKind kind) {
+  if (kind == engine.ElementKind.CLASS) {
+    return ElementKind.CLASS;
+  }
+  if (kind == engine.ElementKind.COMPILATION_UNIT) {
+    return ElementKind.COMPILATION_UNIT;
+  }
+  if (kind == engine.ElementKind.CONSTRUCTOR) {
+    return ElementKind.CONSTRUCTOR;
+  }
+  if (kind == engine.ElementKind.FIELD) {
+    return ElementKind.FIELD;
+  }
+  if (kind == engine.ElementKind.FUNCTION) {
+    return ElementKind.FUNCTION;
+  }
+  if (kind == engine.ElementKind.FUNCTION_TYPE_ALIAS) {
+    return ElementKind.FUNCTION_TYPE_ALIAS;
+  }
+  if (kind == engine.ElementKind.GETTER) {
+    return ElementKind.GETTER;
+  }
+  if (kind == engine.ElementKind.LIBRARY) {
+    return ElementKind.LIBRARY;
+  }
+  if (kind == engine.ElementKind.LOCAL_VARIABLE) {
+    return ElementKind.LOCAL_VARIABLE;
+  }
+  if (kind == engine.ElementKind.METHOD) {
+    return ElementKind.METHOD;
+  }
+  if (kind == engine.ElementKind.PARAMETER) {
+    return ElementKind.PARAMETER;
+  }
+  if (kind == engine.ElementKind.SETTER) {
+    return ElementKind.SETTER;
+  }
+  if (kind == engine.ElementKind.TOP_LEVEL_VARIABLE) {
+    return ElementKind.TOP_LEVEL_VARIABLE;
+  }
+  if (kind == engine.ElementKind.TYPE_PARAMETER) {
+    return ElementKind.TYPE_PARAMETER;
+  }
+  return ElementKind.UNKNOWN;
+}
+
+/**
+ * Returns the [FileEdit] for the given [file], maybe `null`.
+ */
+SourceFileEdit _getChangeFileEdit(SourceChange change, String file) {
+  for (SourceFileEdit fileEdit in change.edits) {
+    if (fileEdit.file == file) {
+      return fileEdit;
+    }
+  }
+  return null;
+}
+
+/**
+ * Compare the lists [listA] and [listB], using [itemEqual] to compare
+ * list elements.
+ */
+bool _listEqual(List listA, List listB, bool itemEqual(a, b)) {
+  if (listA.length != listB.length) {
+    return false;
+  }
+  for (int i = 0; i < listA.length; i++) {
+    if (!itemEqual(listA[i], listB[i])) {
+      return false;
+    }
+  }
+  return true;
+}
+
+/**
+ * Creates a new [Location].
+ */
+Location _locationForArgs(engine.AnalysisContext context, engine.Source source,
+    engine.SourceRange range) {
+  int startLine = 0;
+  int startColumn = 0;
+  {
+    engine.LineInfo lineInfo = context.getLineInfo(source);
+    if (lineInfo != null) {
+      engine.LineInfo_Location offsetLocation =
+          lineInfo.getLocation(range.offset);
+      startLine = offsetLocation.lineNumber;
+      startColumn = offsetLocation.columnNumber;
+    }
+  }
+  return new Location(
+      source.fullName,
+      range.offset,
+      range.length,
+      startLine,
+      startColumn);
+}
+
+/**
+ * Creates a new [Location] for the given [engine.Element].
+ */
+Location _locationFromElement(engine.Element element) {
+  engine.AnalysisContext context = element.context;
+  engine.Source source = element.source;
+  String name = element.displayName;
+  int offset = element.nameOffset;
+  int length = name != null ? name.length : 0;
+  if (element is engine.CompilationUnitElement) {
+    offset = 0;
+    length = 0;
+  }
+  engine.SourceRange range = new engine.SourceRange(offset, length);
+  return _locationForArgs(context, source, range);
+}
+
+/**
+ * Creates a new [Location] for the given [engine.SearchMatch].
+ */
+Location _locationFromMatch(engine.SearchMatch match) {
+  engine.Element enclosingElement = match.element;
+  return _locationForArgs(
+      enclosingElement.context,
+      enclosingElement.source,
+      match.sourceRange);
+}
+
+/**
+ * Creates a new [Location] for the given [engine.AstNode].
+ */
+Location _locationFromNode(engine.AstNode node) {
+  engine.CompilationUnit unit =
+      node.getAncestor((node) => node is engine.CompilationUnit);
+  engine.CompilationUnitElement unitElement = unit.element;
+  engine.AnalysisContext context = unitElement.context;
+  engine.Source source = unitElement.source;
+  engine.SourceRange range = new engine.SourceRange(node.offset, node.length);
+  return _locationForArgs(context, source, range);
+}
+
+/**
+ * Creates a new [Location] for the given [engine.CompilationUnit].
+ */
+Location _locationFromUnit(engine.CompilationUnit unit,
+    engine.SourceRange range) {
+  engine.CompilationUnitElement unitElement = unit.element;
+  engine.AnalysisContext context = unitElement.context;
+  engine.Source source = unitElement.source;
+  return _locationForArgs(context, source, range);
+}
+
+/**
+ * Compare the maps [mapA] and [mapB], using [valueEqual] to compare map
+ * values.
+ */
+bool _mapEqual(Map mapA, Map mapB, bool valueEqual(a, b)) {
+  if (mapA.length != mapB.length) {
+    return false;
+  }
+  for (var key in mapA.keys) {
+    if (!mapB.containsKey(key)) {
+      return false;
+    }
+    if (!valueEqual(mapA[key], mapB[key])) {
+      return false;
+    }
+  }
+  return true;
+}
+
+RefactoringProblemSeverity
+    _maxRefactoringProblemSeverity(RefactoringProblemSeverity a,
+    RefactoringProblemSeverity b) {
+  if (b == null) {
+    return a;
+  }
+  if (a == null) {
+    return b;
+  } else if (a == RefactoringProblemSeverity.INFO) {
+    return b;
+  } else if (a == RefactoringProblemSeverity.WARNING) {
+    if (b == RefactoringProblemSeverity.ERROR ||
+        b == RefactoringProblemSeverity.FATAL) {
+      return b;
+    }
+  } else if (a == RefactoringProblemSeverity.ERROR) {
+    if (b == RefactoringProblemSeverity.FATAL) {
+      return b;
+    }
+  }
+  return a;
+}
+
+/**
+ * Create an OverriddenMember based on an element from the analyzer engine.
+ */
+OverriddenMember _overriddenMemberFromEngine(engine.Element member) {
+  Element element = elementFromEngine(member);
+  String className = member.enclosingElement.displayName;
+  return new OverriddenMember(element, className);
+}
+
+
+/**
+ * Create a SearchResultKind based on a value from the search engine.
+ */
+SearchResultKind _searchResultKindFromEngine(engine.MatchKind kind) {
+  if (kind == engine.MatchKind.DECLARATION) {
+    return SearchResultKind.DECLARATION;
+  }
+  if (kind == engine.MatchKind.READ) {
+    return SearchResultKind.READ;
+  }
+  if (kind == engine.MatchKind.READ_WRITE) {
+    return SearchResultKind.READ_WRITE;
+  }
+  if (kind == engine.MatchKind.WRITE) {
+    return SearchResultKind.WRITE;
+  }
+  if (kind == engine.MatchKind.INVOCATION) {
+    return SearchResultKind.INVOCATION;
+  }
+  if (kind == engine.MatchKind.REFERENCE) {
+    return SearchResultKind.REFERENCE;
+  }
+  return SearchResultKind.UNKNOWN;
+}
+
+
+/**
+ * Type of callbacks used to decode parts of JSON objects.  [jsonPath] is a
+ * string describing the part of the JSON object being decoded, and [value] is
+ * the part to decode.
+ */
+typedef Object JsonDecoderCallback(String jsonPath, Object value);
+
+/**
+ * Base class for decoding JSON objects.  The derived class must implement
+ * error reporting logic.
+ */
+abstract class JsonDecoder {
+  /**
+   * Create an exception to throw if the JSON object at [jsonPath] fails to
+   * match the API definition of [expected].
+   */
+  dynamic mismatch(String jsonPath, String expected);
+
+  /**
+   * Create an exception to throw if the JSON object at [jsonPath] is missing
+   * the key [key].
+   */
+  dynamic missingKey(String jsonPath, String key);
+
+  /**
+   * Decode a JSON object that is expected to be a boolean.  The strings "true"
+   * and "false" are also accepted.
+   */
+  bool _decodeBool(String jsonPath, Object json) {
+    if (json is bool) {
+      return json;
+    } else if (json == 'true') {
+      return true;
+    } else if (json == 'false') {
+      return false;
+    }
+    throw mismatch(jsonPath, 'bool');
+  }
+
+  /**
+   * Decode a JSON object that is expected to be an integer.  A string
+   * representation of an integer is also accepted.
+   */
+  int _decodeInt(String jsonPath, Object json) {
+    if (json is int) {
+      return json;
+    } else if (json is String) {
+      return int.parse(json, onError: (String value) {
+        throw mismatch(jsonPath, 'int');
+      });
+    }
+    throw mismatch(jsonPath, 'int');
+  }
+
+  /**
+   * Decode a JSON object that is expected to be a List.  [decoder] is used to
+   * decode the items in the list.
+   */
+  List _decodeList(String jsonPath, Object json,
+      [JsonDecoderCallback decoder]) {
+    if (json == null) {
+      return [];
+    } else if (json is List) {
+      List result = [];
+      for (int i = 0; i < json.length; i++) {
+        result.add(decoder('$jsonPath[$i]', json[i]));
+      }
+      return result;
+    } else {
+      throw mismatch(jsonPath, 'List');
+    }
+  }
+
+  /**
+   * Decode a JSON object that is expected to be a Map.  [keyDecoder] is used
+   * to decode the keys, and [valueDecoder] is used to decode the values.
+   */
+  Map _decodeMap(String jsonPath, Object json, {JsonDecoderCallback keyDecoder,
+      JsonDecoderCallback valueDecoder}) {
+    if (json == null) {
+      return {};
+    } else if (json is Map) {
+      Map result = {};
+      json.forEach((String key, value) {
+        Object decodedKey;
+        if (keyDecoder != null) {
+          decodedKey = keyDecoder('$jsonPath.key', key);
+        } else {
+          decodedKey = key;
+        }
+        if (valueDecoder != null) {
+          value = valueDecoder('$jsonPath[${JSON.encode(key)}]', value);
+        }
+        result[decodedKey] = value;
+      });
+      return result;
+    } else {
+      throw mismatch(jsonPath, 'Map');
+    }
+  }
+
+  /**
+   * Decode a JSON object that is expected to be a string.
+   */
+  String _decodeString(String jsonPath, Object json) {
+    if (json is String) {
+      return json;
+    } else {
+      throw mismatch(jsonPath, 'String');
+    }
+  }
+
+  /**
+   * Decode a JSON object that is expected to be one of several choices,
+   * where the choices are disambiguated by the contents of the field [field].
+   * [decoders] is a map from each possible string in the field to the decoder
+   * that should be used to decode the JSON object.
+   */
+  Object _decodeUnion(String jsonPath, Map json, String field, Map<String,
+      JsonDecoderCallback> decoders) {
+    if (json is Map) {
+      if (!json.containsKey(field)) {
+        throw missingKey(jsonPath, field);
+      }
+      var disambiguatorPath = '$jsonPath[${JSON.encode(field)}]';
+      String disambiguator = _decodeString(disambiguatorPath, json[field]);
+      if (!decoders.containsKey(disambiguator)) {
+        throw mismatch(disambiguatorPath, 'One of: ${decoders.keys.toList()}');
+      }
+      return decoders[disambiguator](jsonPath, json);
+    } else {
+      throw mismatch(jsonPath, 'Map');
+    }
+  }
+}
+
+
+/**
+ * Instances of the class [Notification] represent a notification from the
+ * server about an event that occurred.
+ */
+class Notification {
+  /**
+   * The name of the JSON attribute containing the name of the event that
+   * triggered the notification.
+   */
+  static const String EVENT = 'event';
+
+  /**
+   * The name of the JSON attribute containing the result values.
+   */
+  static const String PARAMS = 'params';
+
+  /**
+   * The name of the event that triggered the notification.
+   */
+  final String event;
+
+  /**
+   * A table mapping the names of notification parameters to their values, or
+   * null if there are no notification parameters.
+   */
+  Map<String, Object> _params;
+
+  /**
+   * Initialize a newly created [Notification] to have the given [event] name.
+   * If [_params] is provided, it will be used as the params; otherwise no
+   * params will be used.
+   */
+  Notification(this.event, [this._params]);
+
+  /**
+   * Initialize a newly created instance based upon the given JSON data
+   */
+  factory Notification.fromJson(Map<String, Object> json) {
+    return new Notification(json[Notification.EVENT],
+        json[Notification.PARAMS]);
+  }
+
+  /**
+   * Return a table representing the structure of the Json object that will be
+   * sent to the client to represent this response.
+   */
+  Map<String, Object> toJson() {
+    Map<String, Object> jsonObject = {};
+    jsonObject[EVENT] = event;
+    if (_params != null) {
+      jsonObject[PARAMS] = _params;
+    }
+    return jsonObject;
+  }
+}
 
-import 'package:analysis_server/src/services/json.dart';
 
 /**
  * Instances of the class [Request] represent a request that was received.
@@ -41,12 +643,7 @@ class Request {
   /**
    * A table mapping the names of request parameters to their values.
    */
-  final Map<String, Object> params;
-
-  /**
-   * A decoder that can be used to decode strings into JSON objects.
-   */
-  static const JsonDecoder DECODER = const JsonDecoder(null);
+  final Map<String, Object> _params;
 
   /**
    * Initialize a newly created [Request] to have the given [id] and [method]
@@ -54,7 +651,7 @@ class Request {
    * request.  Otherwise an empty "params" map is allocated.
    */
   Request(this.id, this.method, [Map<String, Object> params])
-      : params = params != null ? params : new HashMap<String, Object>();
+      : _params = params != null ? params : new HashMap<String, Object>();
 
   /**
    * Return a request parsed from the given [data], or `null` if the [data] is
@@ -74,7 +671,7 @@ class Request {
    */
   factory Request.fromString(String data) {
     try {
-      var result = DECODER.convert(data);
+      var result = JSON.decode(data);
       if (result is! Map) {
         return null;
       }
@@ -102,212 +699,57 @@ class Request {
     Map<String, Object> jsonObject = new HashMap<String, Object>();
     jsonObject[ID] = id;
     jsonObject[METHOD] = method;
-    if (params.isNotEmpty) {
-      jsonObject[PARAMS] = params;
+    if (_params.isNotEmpty) {
+      jsonObject[PARAMS] = _params;
     }
     return jsonObject;
   }
 }
 
 /**
- * Instances of the class [Response] represent a response to a request.
+ * JsonDecoder for decoding requests.  Errors are reporting by throwing a
+ * [RequestFailure].
  */
-class Response {
+class RequestDecoder extends JsonDecoder {
   /**
-   * The [Response] instance that is returned when a real [Response] cannot
-   * be provided at the moment.
+   * The request being deserialized.
    */
-  static final Response DELAYED_RESPONSE = new Response('DELAYED_RESPONSE');
+  final Request _request;
 
-  /**
-   * The name of the JSON attribute containing the id of the request for which
-   * this is a response.
-   */
-  static const String ID = 'id';
+  RequestDecoder(this._request);
+
+  @override
+  dynamic mismatch(String jsonPath, String expected) {
+    return new RequestFailure(
+        new Response.invalidParameter(_request, jsonPath, 'be $expected'));
+  }
+
+  @override
+  dynamic missingKey(String jsonPath, String key) {
+    return new RequestFailure(
+        new Response.invalidParameter(
+            _request,
+            jsonPath,
+            'contain key ${JSON.encode(key)}'));
+  }
+}
 
+/**
+ * Instances of the class [RequestError] represent information about an error
+ * that occurred while attempting to respond to a [Request].
+ */
+class RequestError {
   /**
-   * The name of the JSON attribute containing the error message.
+   * The name of the JSON attribute containing the code that uniquely identifies
+   * the error that occurred.
    */
-  static const String ERROR = 'error';
+  static const String CODE = 'code';
 
   /**
-   * The name of the JSON attribute containing the result values.
+   * The name of the JSON attribute containing an object with additional data
+   * related to the error.
    */
-  static const String RESULT = 'result';
-
-  /**
-   * The unique identifier used to identify the request that this response is
-   * associated with.
-   */
-  final String id;
-
-  /**
-   * The error that was caused by attempting to handle the request, or `null` if
-   * there was no error.
-   */
-  final RequestError error;
-
-  /**
-   * A table mapping the names of result fields to their values.  Should be
-   * null if there is no result to send.
-   */
-  Map<String, Object> result;
-
-  /**
-   * Initialize a newly created instance to represent a response to a request
-   * with the given [id].  If [result] is provided, it will be used as the
-   * result; otherwise an empty result will be used.  If an [error] is provided
-   * then the response will represent an error condition.
-   */
-  Response(this.id, {this.result, this.error});
-
-  /**
-   * Initialize a newly created instance to represent an error condition caused
-   * by a [request] referencing a context that does not exist.
-   */
-  Response.contextDoesNotExist(Request request)
-    : this(request.id, error: new RequestError('NONEXISTENT_CONTEXT', 'Context does not exist'));
-
-  /**
-   * Initialize a newly created instance to represent an error condition caused
-   * by a [request] that had invalid parameter.  [path] is the path to the
-   * invalid parameter, in Javascript notation (e.g. "foo.bar" means that the
-   * parameter "foo" contained a key "bar" whose value was the wrong type).
-   * [expectation] is a description of the type of data that was expected.
-   */
-  Response.invalidParameter(Request request, String path, String expectation)
-      : this(request.id, error: new RequestError('INVALID_PARAMETER',
-          "Expected parameter $path to $expectation"));
-
-  /**
-   * Initialize a newly created instance to represent an error condition caused
-   * by a malformed request.
-   */
-  Response.invalidRequestFormat()
-    : this('', error: new RequestError('INVALID_REQUEST', 'Invalid request'));
-
-  /**
-   * Initialize a newly created instance to represent an error condition caused
-   * by a [request] that does not have a required parameter.
-   */
-  Response.missingRequiredParameter(Request request, String parameterName)
-    : this(request.id, error: new RequestError('MISSING_PARAMETER', 'Missing required parameter: $parameterName'));
-
-  /**
-   * Initialize a newly created instance to represent an error condition caused
-   * by a [request] that takes a set of analysis options but for which an
-   * unknown analysis option was provided.
-   */
-  Response.unknownAnalysisOption(Request request, String optionName)
-    : this(request.id, error: new RequestError('UNKNOWN_ANALYSIS_OPTION', 'Unknown analysis option: "$optionName"'));
-
-  /**
-   * Initialize a newly created instance to represent an error condition caused
-   * by a [request] that cannot be handled by any known handlers.
-   */
-  Response.unknownRequest(Request request)
-    : this(request.id, error: new RequestError('UNKNOWN_REQUEST', 'Unknown request'));
-
-  Response.contextAlreadyExists(Request request)
-    : this(request.id, error: new RequestError('CONTENT_ALREADY_EXISTS', 'Context already exists'));
-
-  Response.unsupportedFeature(String requestId, String message)
-    : this(requestId, error: new RequestError('UNSUPPORTED_FEATURE', message));
-
-  /**
-   * Initialize a newly created instance to represent an error condition caused
-   * by a `analysis.setSubscriptions` [request] that includes an unknown
-   * analysis service name.
-   */
-  Response.unknownAnalysisService(Request request, String name)
-    : this(request.id, error: new RequestError('UNKNOWN_ANALYSIS_SERVICE', 'Unknown analysis service: "$name"'));
-
-  /**
-   * Initialize a newly created instance to represent an error condition caused
-   * by a `analysis.setPriorityFiles` [request] that includes one or more files
-   * that are not being analyzed.
-   */
-  Response.unanalyzedPriorityFiles(Request request, String fileNames)
-    : this(request.id, error: new RequestError('UNANALYZED_PRIORITY_FILES', "Unanalyzed files cannot be a priority: '$fileNames'"));
-
-  /**
-   * Initialize a newly created instance to represent an error condition caused
-   * by a `analysis.updateOptions` [request] that includes an unknown analysis
-   * option.
-   */
-  Response.unknownOptionName(Request request, String optionName)
-    : this(request.id, error: new RequestError('UNKNOWN_OPTION_NAME', 'Unknown analysis option: "$optionName"'));
-
-  /**
-   * Initialize a newly created instance to represent an error condition caused
-   * by an error during `analysis.getErrors`.
-   */
-  Response.getErrorsError(Request request, String message,
-      Map<String, Object> result)
-    : this(
-        request.id,
-        error: new RequestError('GET_ERRORS_ERROR', 'Error during `analysis.getErrors`: $message.'),
-        result: result);
-
-  /**
-   * Initialize a newly created instance based upon the given JSON data
-   */
-  factory Response.fromJson(Map<String, Object> json) {
-    try {
-      Object id = json[Response.ID];
-      if (id is! String) {
-        return null;
-      }
-      Object error = json[Response.ERROR];
-      RequestError decodedError;
-      if (error is Map) {
-        decodedError = new RequestError.fromJson(error);
-      }
-      Object result = json[Response.RESULT];
-      Map<String, Object> decodedResult;
-      if (result is Map) {
-        decodedResult = result;
-      }
-      return new Response(id, error: decodedError,
-          result: decodedResult);
-    } catch (exception) {
-      return null;
-    }
-  }
-
-  /**
-   * Return a table representing the structure of the Json object that will be
-   * sent to the client to represent this response.
-   */
-  Map<String, Object> toJson() {
-    Map<String, Object> jsonObject = new HashMap<String, Object>();
-    jsonObject[ID] = id;
-    if (error != null) {
-      jsonObject[ERROR] = error.toJson();
-    }
-    if (result != null) {
-      jsonObject[RESULT] = result;
-    }
-    return jsonObject;
-  }
-}
-
-/**
- * Instances of the class [RequestError] represent information about an error
- * that occurred while attempting to respond to a [Request].
- */
-class RequestError {
-  /**
-   * The name of the JSON attribute containing the code that uniquely identifies
-   * the error that occurred.
-   */
-  static const String CODE = 'code';
-
-  /**
-   * The name of the JSON attribute containing an object with additional data
-   * related to the error.
-   */
-  static const String DATA = 'data';
+  static const String DATA = 'data';
 
   /**
    * The name of the JSON attribute containing a short description of the error.
@@ -379,18 +821,35 @@ class RequestError {
   RequestError(this.code, this.message);
 
   /**
-   * Initialize a newly created [Error] to indicate a parse error. Invalid JSON
-   * was received by the server. An error occurred on the server while parsing
-   * the JSON text.
+   * Initialize a newly created [Error] from the given JSON.
    */
-  RequestError.parseError() : this(CODE_PARSE_ERROR, "Parse error");
+  factory RequestError.fromJson(Map<String, Object> json) {
+    try {
+      String code = json[RequestError.CODE];
+      String message = json[RequestError.MESSAGE];
+      Map<String, Object> data = json[RequestError.DATA];
+      RequestError requestError = new RequestError(code, message);
+      if (data != null) {
+        data.forEach((String key, Object value) {
+          requestError.setData(key, value);
+        });
+      }
+      return requestError;
+    } catch (exception) {
+      return null;
+    }
+  }
 
   /**
-   * Initialize a newly created [Error] to indicate that the analysis server
-   * has already been started (and hence won't accept new connections).
+   * Initialize a newly created [Error] to indicate an internal error.
    */
-  RequestError.serverAlreadyStarted()
-    : this(CODE_SERVER_ALREADY_STARTED, "Server already started");
+  RequestError.internalError() : this(CODE_INTERNAL_ERROR, "Internal error");
+
+  /**
+   * Initialize a newly created [Error] to indicate one or more invalid
+   * parameters.
+   */
+  RequestError.invalidParameters() : this(CODE_INVALID_PARAMS, "Invalid parameters");
 
   /**
    * Initialize a newly created [Error] to indicate an invalid request. The
@@ -405,35 +864,18 @@ class RequestError {
   RequestError.methodNotFound() : this(CODE_METHOD_NOT_FOUND, "Method not found");
 
   /**
-   * Initialize a newly created [Error] to indicate one or more invalid
-   * parameters.
-   */
-  RequestError.invalidParameters() : this(CODE_INVALID_PARAMS, "Invalid parameters");
-
-  /**
-   * Initialize a newly created [Error] to indicate an internal error.
+   * Initialize a newly created [Error] to indicate a parse error. Invalid JSON
+   * was received by the server. An error occurred on the server while parsing
+   * the JSON text.
    */
-  RequestError.internalError() : this(CODE_INTERNAL_ERROR, "Internal error");
+  RequestError.parseError() : this(CODE_PARSE_ERROR, "Parse error");
 
   /**
-   * Initialize a newly created [Error] from the given JSON.
+   * Initialize a newly created [Error] to indicate that the analysis server
+   * has already been started (and hence won't accept new connections).
    */
-  factory RequestError.fromJson(Map<String, Object> json) {
-    try {
-      String code = json[RequestError.CODE];
-      String message = json[RequestError.MESSAGE];
-      Map<String, Object> data = json[RequestError.DATA];
-      RequestError requestError = new RequestError(code, message);
-      if (data != null) {
-        data.forEach((String key, Object value) {
-          requestError.setData(key, value);
-        });
-      }
-      return requestError;
-    } catch (exception) {
-      return null;
-    }
-  }
+  RequestError.serverAlreadyStarted()
+    : this(CODE_SERVER_ALREADY_STARTED, "Server already started");
 
   /**
    * Return the value of the data with the given [name], or `null` if there is
@@ -466,123 +908,259 @@ class RequestError {
   String toString() => toJson().toString();
 }
 
+
 /**
- * Instances of the class [Notification] represent a notification from the
- * server about an event that occurred.
+ * Instances of the class [RequestFailure] represent an exception that occurred
+ * during the handling of a request that requires that an error be returned to
+ * the client.
  */
-class Notification {
+class RequestFailure implements Exception {
   /**
-   * The name of the JSON attribute containing the name of the event that
-   * triggered the notification.
+   * The response to be returned as a result of the failure.
    */
-  static const String EVENT = 'event';
+  final Response response;
+
+  /**
+   * Initialize a newly created exception to return the given reponse.
+   */
+  RequestFailure(this.response);
+}
+
+/**
+ * Instances of the class [RequestHandler] implement a handler that can handle
+ * requests and produce responses for them.
+ */
+abstract class RequestHandler {
+  /**
+   * Attempt to handle the given [request]. If the request is not recognized by
+   * this handler, return `null` so that other handlers will be given a chance
+   * to handle it. Otherwise, return the response that should be passed back to
+   * the client.
+   */
+  Response handleRequest(Request request);
+}
+
+/**
+ * Instances of the class [Response] represent a response to a request.
+ */
+class Response {
+  /**
+   * The [Response] instance that is returned when a real [Response] cannot
+   * be provided at the moment.
+   */
+  static final Response DELAYED_RESPONSE = new Response('DELAYED_RESPONSE');
+
+  /**
+   * The name of the JSON attribute containing the id of the request for which
+   * this is a response.
+   */
+  static const String ID = 'id';
+
+  /**
+   * The name of the JSON attribute containing the error message.
+   */
+  static const String ERROR = 'error';
 
   /**
    * The name of the JSON attribute containing the result values.
    */
-  static const String PARAMS = 'params';
+  static const String RESULT = 'result';
 
   /**
-   * The name of the event that triggered the notification.
+   * The unique identifier used to identify the request that this response is
+   * associated with.
    */
-  final String event;
+  final String id;
 
   /**
-   * A table mapping the names of notification parameters to their values, or
-   * null if there are no notification parameters.
+   * The error that was caused by attempting to handle the request, or `null` if
+   * there was no error.
    */
-  Map<String, Object> params;
+  final RequestError error;
 
   /**
-   * Initialize a newly created [Notification] to have the given [event] name.
-   * If [params] is provided, it will be used as the params; otherwise no
-   * params will be used.
+   * A table mapping the names of result fields to their values.  Should be
+   * null if there is no result to send.
+   */
+  Map<String, Object> _result;
+
+  /**
+   * Initialize a newly created instance to represent a response to a request
+   * with the given [id].  If [_result] is provided, it will be used as the
+   * result; otherwise an empty result will be used.  If an [error] is provided
+   * then the response will represent an error condition.
    */
-  Notification(this.event, [this.params]);
+  Response(this.id, {Map<String, Object> result, this.error})
+      : _result = result;
+
+  Response.contextAlreadyExists(Request request)
+    : this(request.id, error: new RequestError('CONTENT_ALREADY_EXISTS', 'Context already exists'));
+
+  /**
+   * Initialize a newly created instance to represent an error condition caused
+   * by a [request] referencing a context that does not exist.
+   */
+  Response.contextDoesNotExist(Request request)
+    : this(request.id, error: new RequestError('NONEXISTENT_CONTEXT', 'Context does not exist'));
 
   /**
    * Initialize a newly created instance based upon the given JSON data
    */
-  factory Notification.fromJson(Map<String, Object> json) {
+  factory Response.fromJson(Map<String, Object> json) {
     try {
-      String event = json[Notification.EVENT];
-      Object params = json[Notification.PARAMS];
-      Notification notification = new Notification(event);
-      if (params is Map) {
-        params.forEach((String key, Object value) {
-          notification.setParameter(key, value);
-        });
+      Object id = json[Response.ID];
+      if (id is! String) {
+        return null;
+      }
+      Object error = json[Response.ERROR];
+      RequestError decodedError;
+      if (error is Map) {
+        decodedError = new RequestError.fromJson(error);
+      }
+      Object result = json[Response.RESULT];
+      Map<String, Object> decodedResult;
+      if (result is Map) {
+        decodedResult = result;
       }
-      return notification;
+      return new Response(id, error: decodedError,
+          result: decodedResult);
     } catch (exception) {
       return null;
     }
   }
 
   /**
-   * Set the value of the parameter with the given [name] to the given [value].
+   * Initialize a newly created instance to represent an error condition caused
+   * by an error during `analysis.getErrors`.
    */
-  void setParameter(String name, Object value) {
-    if (params == null) {
-      params = new HashMap<String, Object>();
-    }
-    params[name] = _toJson(value);
-  }
+  Response.getErrorsError(Request request, String message,
+      Map<String, Object> result)
+    : this(
+        request.id,
+        error: new RequestError('GET_ERRORS_ERROR', 'Error during `analysis.getErrors`: $message.'),
+        result: result);
+
+  /**
+   * Initialize a newly created instance to represent an error condition caused
+   * by a [request] that had invalid parameter.  [path] is the path to the
+   * invalid parameter, in Javascript notation (e.g. "foo.bar" means that the
+   * parameter "foo" contained a key "bar" whose value was the wrong type).
+   * [expectation] is a description of the type of data that was expected.
+   */
+  Response.invalidParameter(Request request, String path, String expectation)
+      : this(request.id, error: new RequestError('INVALID_PARAMETER',
+          "Expected parameter $path to $expectation"));
+
+  /**
+   * Initialize a newly created instance to represent an error condition caused
+   * by a malformed request.
+   */
+  Response.invalidRequestFormat()
+    : this('', error: new RequestError('INVALID_REQUEST', 'Invalid request'));
+
+  /**
+   * Initialize a newly created instance to represent an error condition caused
+   * by a [request] that does not have a required parameter.
+   */
+  Response.missingRequiredParameter(Request request, String parameterName)
+    : this(request.id, error: new RequestError('MISSING_PARAMETER', 'Missing required parameter: $parameterName'));
+
+  /**
+   * Initialize a newly created instance to represent an error condition caused
+   * by a `analysis.setPriorityFiles` [request] that includes one or more files
+   * that are not being analyzed.
+   */
+  Response.unanalyzedPriorityFiles(Request request, String fileNames)
+    : this(request.id, error: new RequestError('UNANALYZED_PRIORITY_FILES', "Unanalyzed files cannot be a priority: '$fileNames'"));
+
+  /**
+   * Initialize a newly created instance to represent an error condition caused
+   * by a [request] that takes a set of analysis options but for which an
+   * unknown analysis option was provided.
+   */
+  Response.unknownAnalysisOption(Request request, String optionName)
+    : this(request.id, error: new RequestError('UNKNOWN_ANALYSIS_OPTION', 'Unknown analysis option: "$optionName"'));
+
+  /**
+   * Initialize a newly created instance to represent an error condition caused
+   * by a `analysis.setSubscriptions` [request] that includes an unknown
+   * analysis service name.
+   */
+  Response.unknownAnalysisService(Request request, String name)
+    : this(request.id, error: new RequestError('UNKNOWN_ANALYSIS_SERVICE', 'Unknown analysis service: "$name"'));
+
+  /**
+   * Initialize a newly created instance to represent an error condition caused
+   * by a `analysis.updateOptions` [request] that includes an unknown analysis
+   * option.
+   */
+  Response.unknownOptionName(Request request, String optionName)
+    : this(request.id, error: new RequestError('UNKNOWN_OPTION_NAME', 'Unknown analysis option: "$optionName"'));
+
+  /**
+   * Initialize a newly created instance to represent an error condition caused
+   * by a [request] that cannot be handled by any known handlers.
+   */
+  Response.unknownRequest(Request request)
+    : this(request.id, error: new RequestError('UNKNOWN_REQUEST', 'Unknown request'));
+
+  Response.unsupportedFeature(String requestId, String message)
+    : this(requestId, error: new RequestError('UNSUPPORTED_FEATURE', message));
 
   /**
    * Return a table representing the structure of the Json object that will be
    * sent to the client to represent this response.
    */
   Map<String, Object> toJson() {
-    Map<String, Object> jsonObject = {};
-    jsonObject[EVENT] = event;
-    if (params != null) {
-      jsonObject[PARAMS] = params;
+    Map<String, Object> jsonObject = new HashMap<String, Object>();
+    jsonObject[ID] = id;
+    if (error != null) {
+      jsonObject[ERROR] = error.toJson();
+    }
+    if (_result != null) {
+      jsonObject[RESULT] = _result;
     }
     return jsonObject;
   }
 }
 
 /**
- * Instances of the class [RequestHandler] implement a handler that can handle
- * requests and produce responses for them.
+ * JsonDecoder for decoding responses from the server.  This is intended to be
+ * used only for testing.  Errors are reported using bare [Exception] objects.
  */
-abstract class RequestHandler {
-  /**
-   * Attempt to handle the given [request]. If the request is not recognized by
-   * this handler, return `null` so that other handlers will be given a chance
-   * to handle it. Otherwise, return the response that should be passed back to
-   * the client.
-   */
-  Response handleRequest(Request request);
-}
-
-/**
- * Instances of the class [RequestFailure] represent an exception that occurred
- * during the handling of a request that requires that an error be returned to
- * the client.
- */
-class RequestFailure implements Exception {
-  /**
-   * The response to be returned as a result of the failure.
-   */
-  final Response response;
+class ResponseDecoder extends JsonDecoder {
+  @override
+  dynamic mismatch(String jsonPath, String expected) {
+    return new Exception('Expected $expected at $jsonPath');
+  }
 
-  /**
-   * Initialize a newly created exception to return the given reponse.
-   */
-  RequestFailure(this.response);
+  @override
+  dynamic missingKey(String jsonPath, String key) {
+    return new Exception('Missing key $key at $jsonPath');
+  }
 }
 
 /**
- * Returns a JSON presention of [value].
+ * Jenkins hash function, optimized for small integers.  Borrowed from
+ * sdk/lib/math/jenkins_smi_hash.dart.
+ *
+ * TODO(paulberry): Move to somewhere that can be shared with other code.
  */
-_toJson(Object value) {
-  if (value is HasToJson) {
-    return value.toJson();
+class _JenkinsSmiHash {
+  static int combine(int hash, int value) {
+    hash = 0x1fffffff & (hash + value);
+    hash = 0x1fffffff & (hash + ((0x0007ffff & hash) << 10));
+    return hash ^ (hash >> 6);
   }
-  if (value is Iterable) {
-    return value.map((item) => _toJson(item)).toList();
+
+  static int finish(int hash) {
+    hash = 0x1fffffff & (hash + ((0x03ffffff & hash) << 3));
+    hash = hash ^ (hash >> 11);
+    return 0x1fffffff & (hash + ((0x00003fff & hash) << 15));
   }
-  return value;
+
+  static int hash2(a, b) => finish(combine(combine(0, a), b));
+
+  static int hash4(a, b, c, d) =>
+      finish(combine(combine(combine(combine(0, a), b), c), d));
 }