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_services/constants.dart';
import 'package:analysis_services/json.dart';
import 'package:analyzer/src/generated/ast.dart';
import 'package:analyzer/src/generated/element.dart';


/**
 * Converts [str] from a Dart Doc string with slashes and stars to a plain text
 * representation of the comment.
 */
String _removeDartDocDelimiters(String str) {
  if (str == null) {
    return null;
  }
  // remove /** */
  if (str.startsWith('/**')) {
    str = str.substring(3);
  }
  if (str.endsWith("*/")) {
    str = str.substring(0, str.length - 2);
  }
  str = str.trim();
  // remove leading '* '
  List<String> lines = str.split('\n');
  StringBuffer sb = new StringBuffer();
  bool firstLine = true;
  for (String line in lines) {
    line = line.trim();
    if (line.startsWith("*")) {
      line = line.substring(1);
      if (line.startsWith(" ")) {
        line = line.substring(1);
      }
    } else if (line.startsWith("///")) {
      line = line.substring(3);
      if (line.startsWith(" ")) {
        line = line.substring(1);
      }
    }
    if (!firstLine) {
      sb.write('\n');
    }
    firstLine = false;
    sb.write(line);
  }
  str = sb.toString();
  // done
  return str;
}


/**
 * 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`.
   */
  Hover compute() {
    AstNode node = new NodeLocator.con1(_offset).searchWithin(_unit);
    if (node is Expression) {
      Hover hover = new Hover(node.offset, node.length);
      // 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();
        hover.elementKind = element.kind.displayName;
        // library
        LibraryElement library = element.library;
        if (library != null) {
          hover.containingLibraryName = library.name;
          hover.containingLibraryPath = library.source.fullName;
        }
        // documentation
        String dartDoc = element.computeDocumentationComment();
        dartDoc = _removeDartDocDelimiters(dartDoc);
        hover.dartDoc = dartDoc;
      }
      // parameter
      hover.parameter = _safeToString(node.bestParameterElement);
      // types
      hover.staticType = _safeToString(node.staticType);
      hover.propagatedType = _safeToString(node.propagatedType);
      // done
      return hover;
    }
    // not an expression
    return null;
  }

  static _safeToString(obj) => obj != null ? obj.toString() : null;
}


class Hover implements HasToJson {
  final int offset;
  final int length;
  String containingLibraryName;
  String containingLibraryPath;
  String dartDoc;
  String elementDescription;
  String elementKind;
  String parameter;
  String propagatedType;
  String staticType;

  Hover(this.offset, this.length);

  factory Hover.fromJson(Map<String, Object> map) {
    int offset = map[OFFSET];
    int length = map[LENGTH];
    Hover hover = new Hover(offset, length);
    hover.containingLibraryName = map[CONTAINING_LIBRARY_NAME];
    hover.containingLibraryPath = map[CONTAINING_LIBRARY_PATH];
    hover.dartDoc = map[DART_DOC];
    hover.elementDescription = map[ELEMENT_DESCRIPTION];
    hover.elementKind = map[ELEMENT_KIND];
    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>();
    json[OFFSET] = offset;
    json[LENGTH] = length;
    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 (elementKind != null) {
      json[ELEMENT_KIND] = elementKind;
    }
    if (parameter != null) {
      json[PARAMETER] = parameter;
    }
    if (propagatedType != null) {
      json[PROPAGATED_TYPE] = propagatedType;
    }
    if (staticType != null) {
      json[STATIC_TYPE] = staticType;
    }
    return json;
  }
}