Add constructor impl/tests + additional function tests for getSignature

Bug: #27034
Change-Id: Ie47f76d4197dbcdec0fcfdada7914fdf986731ec
Reviewed-on: https://dart-review.googlesource.com/66540
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
Commit-Queue: Danny Tuppeny <dantup@google.com>

pkg/analysis_server/doc/api.html

@@ -4250,6 +4250,13 @@ <h2 class="domain"><a name="types">Types</a></h2>
           which does not match a file currently subject to
           analysis.
         </p>
+      </dd><dt class="value">GET_SIGNATURE_INVALID_OFFSET</dt><dd>
+
+        <p>
+          An "analysis.getSignature" request specified an offset
+          which is not a valid location within for the contents of
+          the file specified FilePath.
+        </p>
       </dd><dt class="value">GET_SIGNATURE_UNKNOWN_FUNCTION</dt><dd>
 
         <p>

pkg/analysis_server/lib/protocol/protocol.dart

@@ -497,6 +497,16 @@ class Response {
             error: new RequestError(RequestErrorCode.GET_SIGNATURE_INVALID_FILE,
                 'Error during `analysis.getSignature`: invalid file.'));
 
+  /**
+   * Initialize a newly created instance to represent the
+   * GET_SIGNATURE_INVALID_OFFSET error condition.
+   */
+  Response.getSignatureInvalidOffset(Request request)
+      : this(request.id,
+            error: new RequestError(
+                RequestErrorCode.GET_SIGNATURE_INVALID_OFFSET,
+                'Error during `analysis.getSignature`: invalid offset.'));
+
   /**
    * Initialize a newly created instance to represent the
    * GET_SIGNATURE_UNKNOWN_FUNCTION error condition.

pkg/analysis_server/lib/protocol/protocol_generated.dart

@@ -2017,7 +2017,7 @@ class AnalysisGetSignatureParams implements RequestParams {
  *
  * {
  *   "name": String
- *   "dartdoc": String
+ *   "dartdoc": optional String
  *   "parameters": List<ParameterInfo>
  *   "selectedParameterIndex": int
  * }
@@ -2063,7 +2063,6 @@ class AnalysisGetSignatureResult implements ResponseResult {
    * dartdoc.
    */
   void set dartdoc(String value) {
-    assert(value != null);
     this._dartdoc = value;
   }
 
@@ -2097,8 +2096,9 @@ class AnalysisGetSignatureResult implements ResponseResult {
     this._selectedParameterIndex = value;
   }
 
-  AnalysisGetSignatureResult(String name, String dartdoc,
-      List<ParameterInfo> parameters, int selectedParameterIndex) {
+  AnalysisGetSignatureResult(
+      String name, List<ParameterInfo> parameters, int selectedParameterIndex,
+      {String dartdoc}) {
     this.name = name;
     this.dartdoc = dartdoc;
     this.parameters = parameters;
@@ -2121,8 +2121,6 @@ class AnalysisGetSignatureResult implements ResponseResult {
       if (json.containsKey("dartdoc")) {
         dartdoc =
             jsonDecoder.decodeString(jsonPath + ".dartdoc", json["dartdoc"]);
-      } else {
-        throw jsonDecoder.mismatch(jsonPath, "dartdoc");
       }
       List<ParameterInfo> parameters;
       if (json.containsKey("parameters")) {
@@ -2143,7 +2141,8 @@ class AnalysisGetSignatureResult implements ResponseResult {
         throw jsonDecoder.mismatch(jsonPath, "selectedParameterIndex");
       }
       return new AnalysisGetSignatureResult(
-          name, dartdoc, parameters, selectedParameterIndex);
+          name, parameters, selectedParameterIndex,
+          dartdoc: dartdoc);
     } else {
       throw jsonDecoder.mismatch(
           jsonPath, "analysis.getSignature result", json);
@@ -2161,7 +2160,9 @@ class AnalysisGetSignatureResult implements ResponseResult {
   Map<String, dynamic> toJson() {
     Map<String, dynamic> result = {};
     result["name"] = name;
-    result["dartdoc"] = dartdoc;
+    if (dartdoc != null) {
+      result["dartdoc"] = dartdoc;
+    }
     result["parameters"] =
         parameters.map((ParameterInfo value) => value.toJson()).toList();
     result["selectedParameterIndex"] = selectedParameterIndex;
@@ -15606,6 +15607,7 @@ class RequestError implements HasToJson {
  *   GET_NAVIGATION_INVALID_FILE
  *   GET_REACHABLE_SOURCES_INVALID_FILE
  *   GET_SIGNATURE_INVALID_FILE
+ *   GET_SIGNATURE_INVALID_OFFSET
  *   GET_SIGNATURE_UNKNOWN_FUNCTION
  *   IMPORT_ELEMENTS_INVALID_FILE
  *   INVALID_ANALYSIS_ROOT
@@ -15705,6 +15707,13 @@ class RequestErrorCode implements Enum {
   static const RequestErrorCode GET_SIGNATURE_INVALID_FILE =
       const RequestErrorCode._("GET_SIGNATURE_INVALID_FILE");
 
+  /**
+   * An "analysis.getSignature" request specified an offset which is not a
+   * valid location within for the contents of the file specified FilePath.
+   */
+  static const RequestErrorCode GET_SIGNATURE_INVALID_OFFSET =
+      const RequestErrorCode._("GET_SIGNATURE_INVALID_OFFSET");
+
   /**
    * An "analysis.getSignature" request specified an offset that could not be
    * matched to a function call.
@@ -15853,6 +15862,7 @@ class RequestErrorCode implements Enum {
     GET_NAVIGATION_INVALID_FILE,
     GET_REACHABLE_SOURCES_INVALID_FILE,
     GET_SIGNATURE_INVALID_FILE,
+    GET_SIGNATURE_INVALID_OFFSET,
     GET_SIGNATURE_UNKNOWN_FUNCTION,
     IMPORT_ELEMENTS_INVALID_FILE,
     INVALID_ANALYSIS_ROOT,
@@ -15902,6 +15912,8 @@ class RequestErrorCode implements Enum {
         return GET_REACHABLE_SOURCES_INVALID_FILE;
       case "GET_SIGNATURE_INVALID_FILE":
         return GET_SIGNATURE_INVALID_FILE;
+      case "GET_SIGNATURE_INVALID_OFFSET":
+        return GET_SIGNATURE_INVALID_OFFSET;
       case "GET_SIGNATURE_UNKNOWN_FUNCTION":
         return GET_SIGNATURE_UNKNOWN_FUNCTION;
       case "IMPORT_ELEMENTS_INVALID_FILE":

pkg/analysis_server/lib/src/computer/computer_signature.dart

@@ -14,36 +14,44 @@ import 'package:analyzer/src/dart/ast/utilities.dart';
  * A computer for the signature at the specified offset of a Dart [CompilationUnit].
  */
 class DartUnitSignatureComputer {
-  final CompilationUnit _unit;
-  final int _offset;
+  final AstNode _node;
+  DartUnitSignatureComputer(CompilationUnit _unit, int _offset)
+      : _node = new NodeLocator(_offset).searchWithin(_unit);
 
-  DartUnitSignatureComputer(this._unit, this._offset);
+  bool get offsetIsValid => _node != null;
 
   /**
    * Returns the computed signature information, maybe `null`.
    */
   AnalysisGetSignatureResult compute() {
-    AstNode node = new NodeLocator(_offset).searchWithin(_unit);
-    if (node == null) {
+    if (_node == null) {
       return null;
     }
 
     // Find the closest argument list.
-    while (node != null && !(node is ArgumentList)) {
-      node = node.parent;
+    var argsNode = _node;
+    while (argsNode != null && !(argsNode is ArgumentList)) {
+      argsNode = argsNode.parent;
     }
 
-    if (node == null) {
+    if (argsNode == null) {
       return null;
     }
 
-    final args = node;
+    final args = argsNode;
     String name;
     ExecutableElement execElement;
     if (args.parent is MethodInvocation) {
       MethodInvocation method = args.parent;
       name = method.methodName.name;
       execElement = ElementLocator.locate(method) as ExecutableElement;
+    } else if (args.parent is InstanceCreationExpression) {
+      InstanceCreationExpression constructor = args.parent;
+      name = constructor.constructorName.type.name.name;
+      if (constructor.constructorName.name != null) {
+        name += ".${constructor.constructorName.name.name}";
+      }
+      execElement = ElementLocator.locate(constructor) as ExecutableElement;
     }
 
     if (execElement == null) {
@@ -53,8 +61,8 @@ class DartUnitSignatureComputer {
     final parameters =
         execElement.parameters.map((p) => _convertParam(p)).toList();
 
-    return new AnalysisGetSignatureResult(name,
-        DartUnitHoverComputer.computeDocumentation(execElement), parameters, 0);
+    return new AnalysisGetSignatureResult(name, parameters, 0,
+        dartdoc: DartUnitHoverComputer.computeDocumentation(execElement));
   }
 
   ParameterInfo _convertParam(ParameterElement param) {

pkg/analysis_server/lib/src/domain_analysis.dart

@@ -262,16 +262,21 @@ class AnalysisDomainHandler extends AbstractRequestHandler {
       return;
     }
 
-    // Prepare the signature.
-    var signature =
-        new DartUnitSignatureComputer(unit, params.offset).compute();
+    // Ensure the offset provided is a valid location in the file.
+    final computer = new DartUnitSignatureComputer(unit, params.offset);
+    if (!computer.offsetIsValid) {
+      server.sendResponse(Response.getSignatureInvalidOffset(request));
+      return;
+    }
 
-    // Send the response.
-    if (signature != null) {
-      server.sendResponse(signature.toResponse(request.id));
-    } else {
+    // Try to get a signature.
+    final signature = computer.compute();
+    if (signature == null) {
       server.sendResponse(Response.getSignatureUnknownFunction(request));
+      return;
     }
+
+    server.sendResponse(signature.toResponse(request.id));
   }
 
   @override