Implementation for 'analysis.getHover'.

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

+// Copyright (c) 2014, 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.
+
+library computer.hover;
+
+import 'dart:collection';
+
+import 'package:analysis_server/src/constants.dart';
+import 'package:analyzer/src/generated/ast.dart';
+import 'package:analyzer/src/generated/element.dart';
+
+
+/**
+ * A computer for the hover at the specified offset of a Dart [CompilationUnit].
+ */
+class DartUnitHoverComputer {
+  final CompilationUnit _unit;
+  final int _offset;
+
+  DartUnitHoverComputer(this._unit, this._offset);
+
+  /**
+   * Returns the computed hover, maybe `null`.
+   */
+  Map<String, Object> compute() {
+    AstNode node = new NodeLocator.con1(_offset).searchWithin(_unit);
+    if (node is Expression) {
+      Hover hover = new Hover();
+      // element
+      Element element = ElementLocator.locateWithOffset(node, _offset);
+      if (element != null) {
+        // variable, if synthetic accessor
+        if (element is PropertyAccessorElement) {
+          PropertyAccessorElement accessor = element;
+          if (accessor.isSynthetic) {
+            element = accessor.variable;
+          }
+        }
+        // description
+        hover.elementDescription = element.toString();
+        // library
+        LibraryElement library = element.library;
+        if (library != null) {
+          hover.containingLibraryName = library.name;
+          hover.containingLibraryPath = library.source.fullName;
+        }
+        // documentation
+        hover.dartDoc = element.computeDocumentationComment();
+      }
+      // parameter
+      hover.parameter = _safeToString(node.bestParameterElement);
+      // types
+      hover.staticType = _safeToString(node.staticType);
+      hover.propagatedType = _safeToString(node.propagatedType);
+      // done
+      return hover.toJson();
+    }
+    // not an expression
+    return null;
+  }
+
+  static _safeToString(obj) => obj != null ? obj.toString() : null;
+}
+
+
+class Hover {
+  String containingLibraryName;
+  String containingLibraryPath;
+  String dartDoc;
+  String elementDescription;
+  String parameter;
+  String propagatedType;
+  String staticType;
+
+  Hover();
+
+  factory Hover.fromJson(Map<String, Object> map) {
+    Hover hover = new Hover();
+    hover.containingLibraryName = map[CONTAINING_LIBRARY_NAME];
+    hover.containingLibraryPath = map[CONTAINING_LIBRARY_PATH];
+    hover.dartDoc = map[DART_DOC];
+    hover.elementDescription = map[ELEMENT_DESCRIPTION];
+    hover.parameter = map[PARAMETER];
+    hover.propagatedType = map[PROPAGATED_TYPE];
+    hover.staticType = map[STATIC_TYPE];
+    return hover;
+  }
+
+  Map<String, Object> toJson() {
+    Map<String, Object> json = new HashMap<String, Object>();
+    if (containingLibraryName != null) {
+      json[CONTAINING_LIBRARY_NAME] = containingLibraryName;
+    }
+    if (containingLibraryName != null) {
+      json[CONTAINING_LIBRARY_PATH] = containingLibraryPath;
+    }
+    if (dartDoc != null) {
+      json[DART_DOC] = dartDoc;
+    }
+    if (elementDescription != null) {
+      json[ELEMENT_DESCRIPTION] = elementDescription;
+    }
+    if (parameter != null) {
+      json[PARAMETER] = parameter;
+    }
+    if (propagatedType != null) {
+      json[PROPAGATED_TYPE] = propagatedType;
+    }
+    if (staticType != null) {
+      json[STATIC_TYPE] = staticType;
+    }
+    return json;
+  }
+}