vala/valapropertyaccessor.vala

   1 /* valapropertyaccessor.vala
   2  *
   3  * Copyright (C) 2006-2010  Jürg Billeter
   4  *
   5  * This library is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU Lesser General Public
   7  * License as published by the Free Software Foundation; either
   8  * version 2.1 of the License, or (at your option) any later version.
   9
  10  * This library is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * Lesser General Public License for more details.
  14
  15  * You should have received a copy of the GNU Lesser General Public
  16  * License along with this library; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301  USA
  18  *
  19  * Author:
  20  *      Jürg Billeter <j@bitron.ch>
  21  */
  22
  23 using GLib;
  24
  25 /**
  26  * Represents a get or set accessor of a property in the source code.
  27  */
  28 public class Vala.PropertyAccessor : Subroutine {
  29         /**
  30          * The corresponding property.
  31          */
  32         public Property prop {
  33                 get { return parent_symbol as Property; }
  34         }
  35
  36         /**
  37          * The property type.
  38          */
  39         public DataType? value_type {
  40                 get { return _value_type; }
  41                 private set {
  42                         _value_type = value;
  43                         if (value != null) {
  44                                 _value_type.parent_node = this;
  45                         }
  46                 }
  47         }
  48
  49         /**
  50          * Specifies whether this accessor may be used to get the property.
  51          */
  52         public bool readable { get; private set; }
  53
  54         /**
  55          * Specifies whether this accessor may be used to set the property.
  56          */
  57         public bool writable { get; private set; }
  58
  59         /**
  60          * Specifies whether this accessor may be used to construct the
  61          * property.
  62          */
  63         public bool construction { get; private set; }
  64
  65         /**
  66          * True if the body was automatically generated
  67          */
  68         public bool automatic_body { get; private set; }
  69
  70         public override bool has_result {
  71                 get { return readable; }
  72         }
  73
  74         /**
  75          * Represents the generated value parameter in a set accessor.
  76          */
  77         public Parameter value_parameter { get; private set; }
  78
  79         private DataType _value_type;
  80
  81         /**
  82          * Creates a new property accessor.
  83          *
  84          * @param readable           true if get accessor, false otherwise
  85          * @param writable           true if set accessor, false otherwise
  86          * @param construction       true if construct accessor, false otherwise
  87          * @param body               accessor body
  88          * @param source_reference   reference to source code
  89          * @return                   newly created property accessor
  90          */
  91         public PropertyAccessor (bool readable, bool writable, bool construction, DataType? value_type, Block? body, SourceReference? source_reference, Comment? comment = null) {
  92                 base (null, source_reference, comment);
  93                 this.readable = readable;
  94                 this.writable = writable;
  95                 this.construction = construction;
  96                 this.value_type = value_type;
  97                 this.body = body;
  98                 this.access = SymbolAccessibility.PUBLIC;
  99         }
 100
 101         public override void accept (CodeVisitor visitor) {
 102                 visitor.visit_property_accessor (this);
 103         }
 104
 105         public override void accept_children (CodeVisitor visitor) {
 106                 value_type.accept (visitor);
 107
 108                 if (result_var != null) {
 109                         result_var.accept (visitor);
 110                 }
 111
 112                 if (body != null) {
 113                         body.accept (visitor);
 114                 }
 115         }
 116
 117         /**
 118          * Get the method representing this property accessor
 119          * @return   null if the accessor is neither readable nor writable
 120          */
 121         public Method? get_method () {
 122                 Method? m = null;
 123                 if (readable) {
 124                         m = new Method ("get_%s".printf (prop.name), value_type, source_reference, comment);
 125                 } else if (writable) {
 126                         m = new Method ("set_%s".printf (prop.name), new VoidType(), source_reference, comment);
 127                         m.add_parameter (value_parameter.copy ());
 128                 }
 129
 130                 if (m != null) {
 131                         m.owner = prop.owner;
 132                         m.access = access;
 133                         m.binding = prop.binding;
 134                         m.is_abstract = prop.is_abstract;
 135                         m.is_virtual = prop.is_virtual;
 136                 }
 137
 138                 return m;
 139         }
 140
 141         public override bool check (CodeContext context) {
 142                 if (checked) {
 143                         return !error;
 144                 }
 145
 146                 checked = true;
 147
 148                 if (!value_type.check (context)) {
 149                         error = true;
 150                         return false;
 151                 }
 152
 153                 var old_symbol = context.analyzer.current_symbol;
 154
 155                 context.analyzer.current_symbol = this;
 156
 157                 if (writable || construction) {
 158                         value_parameter = new Parameter ("value", value_type, source_reference);
 159                 }
 160
 161                 if (prop.source_type == SourceFileType.SOURCE) {
 162                         if (body == null && !prop.interface_only && !prop.is_abstract) {
 163                                 /* no accessor body specified, insert default body */
 164
 165                                 automatic_body = true;
 166                                 body = new Block (source_reference);
 167                                 var ma = new MemberAccess.simple ("_%s".printf (prop.name), source_reference);
 168                                 if (readable) {
 169                                         body.add_statement (new ReturnStatement (ma, source_reference));
 170                                 } else {
 171                                         Expression value = new MemberAccess.simple ("value", source_reference);
 172                                         if (value_type.value_owned) {
 173                                                 value = new ReferenceTransferExpression (value, source_reference);
 174                                         }
 175                                         var assignment = new Assignment (ma, value, AssignmentOperator.SIMPLE, source_reference);
 176                                         body.add_statement (new ExpressionStatement (assignment));
 177                                 }
 178                         }
 179                 }
 180
 181                 if ((prop.is_abstract || prop.is_virtual || prop.overrides) && access == SymbolAccessibility.PRIVATE) {
 182                         error = true;
 183                         Report.error (source_reference, "Property `%s' with private accessor cannot be marked as abstract, virtual or override".printf (prop.get_full_name ()));
 184                         return false;
 185                 }
 186
 187                 if (body != null && prop.is_abstract) {
 188                         error = true;
 189                         Report.error (source_reference, "Accessor of abstract property `%s' cannot have body".printf (prop.get_full_name ()));
 190                         return false;
 191                 }
 192
 193                 if (body != null) {
 194                         if (writable || construction) {
 195                                 body.scope.add (value_parameter.name, value_parameter);
 196                         }
 197
 198                         body.check (context);
 199
 200                         foreach (DataType body_error_type in body.get_error_types ()) {
 201                                 if (!((ErrorType) body_error_type).dynamic_error) {
 202                                         Report.warning (body_error_type.source_reference, "unhandled error `%s'".printf (body_error_type.to_string()));
 203                                 }
 204                         }
 205                 }
 206
 207                 context.analyzer.current_symbol = old_symbol;
 208
 209                 return !error;
 210         }
 211
 212         public override void replace_type (DataType old_type, DataType new_type) {
 213                 if (value_type == old_type) {
 214                         value_type = new_type;
 215                 }
 216         }
 217 }