vala/valablock.vala

   1 /* valablock.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 source code block.
  27  */
  28 public class Vala.Block : Symbol, Statement {
  29         /**
  30          * Specifies whether this block contains a jump statement. This
  31          * information can be used to remove unreachable block cleanup code.
  32          */
  33         public bool contains_jump_statement { get; set; }
  34
  35         public bool captured { get; set; }
  36
  37         private List<Statement> statement_list = new ArrayList<Statement> ();
  38         private List<LocalVariable> local_variables = new ArrayList<LocalVariable> ();
  39         private List<Constant> local_constants = new ArrayList<Constant> ();
  40
  41         /**
  42          * Creates a new block.
  43          *
  44          * @param source_reference  reference to source code
  45          */
  46         public Block (SourceReference? source_reference) {
  47                 base (null, source_reference);
  48         }
  49
  50         /**
  51          * Append a statement to this block.
  52          *
  53          * @param stmt a statement
  54          */
  55         public void add_statement (Statement stmt) {
  56                 stmt.parent_node = this;
  57                 statement_list.add (stmt);
  58         }
  59
  60         public void insert_statement (int index, Statement stmt) {
  61                 stmt.parent_node = this;
  62                 statement_list.insert (index, stmt);
  63         }
  64
  65         /**
  66          * Returns a copy of the list of statements.
  67          *
  68          * @return statement list
  69          */
  70         public List<Statement> get_statements () {
  71                 var list = new ArrayList<Statement> ();
  72                 foreach (Statement stmt in statement_list) {
  73                         var stmt_list = stmt as StatementList;
  74                         if (stmt_list != null) {
  75                                 for (int i = 0; i < stmt_list.length; i++) {
  76                                         list.add (stmt_list.get (i));
  77                                 }
  78                         } else {
  79                                 list.add (stmt);
  80                         }
  81                 }
  82                 return list;
  83         }
  84
  85         /**
  86          * Add a local variable to this block.
  87          *
  88          * @param local a variable declarator
  89          */
  90         public void add_local_variable (LocalVariable local) {
  91                 var parent_block = parent_symbol;
  92                 while (parent_block is Block || parent_block is Method || parent_block is PropertyAccessor) {
  93                         if (parent_block.scope.lookup (local.name) != null) {
  94                                 Report.error (local.source_reference, "Local variable `%s' conflicts with a local variable or constant declared in a parent scope".printf (local.name));
  95                                 break;
  96                         }
  97                         parent_block = parent_block.parent_symbol;
  98                 }
  99                 local_variables.add (local);
 100         }
 101
 102         public void remove_local_variable (LocalVariable local) {
 103                 local_variables.remove (local);
 104         }
 105
 106         /**
 107          * Returns a copy of the list of local variables.
 108          *
 109          * @return variable declarator list
 110          */
 111         public List<LocalVariable> get_local_variables () {
 112                 return local_variables;
 113         }
 114
 115         public void add_local_constant (Constant constant) {
 116                 var parent_block = parent_symbol;
 117                 while (parent_block is Block || parent_block is Method || parent_block is PropertyAccessor) {
 118                         if (parent_block.scope.lookup (constant.name) != null) {
 119                                 Report.error (constant.source_reference, "Local constant `%s' conflicts with a local variable or constant declared in a parent scope".printf (constant.name));
 120                                 break;
 121                         }
 122                         parent_block = parent_block.parent_symbol;
 123                 }
 124                 local_constants.add (constant);
 125                 scope.add (constant.name, constant);
 126         }
 127
 128         public override void accept (CodeVisitor visitor) {
 129                 visitor.visit_block (this);
 130         }
 131
 132         public override void accept_children (CodeVisitor visitor) {
 133                 foreach (Statement stmt in statement_list) {
 134                         stmt.accept (visitor);
 135                 }
 136         }
 137
 138         public override bool check (CodeContext context) {
 139                 if (checked) {
 140                         return !error;
 141                 }
 142
 143                 checked = true;
 144
 145                 owner = context.analyzer.current_symbol.scope;
 146
 147                 var old_symbol = context.analyzer.current_symbol;
 148                 var old_insert_block = context.analyzer.insert_block;
 149                 context.analyzer.current_symbol = this;
 150                 context.analyzer.insert_block = this;
 151
 152                 for (int i = 0; i < statement_list.size; i++) {
 153                         statement_list[i].check (context);
 154                 }
 155
 156                 foreach (LocalVariable local in get_local_variables ()) {
 157                         local.active = false;
 158                 }
 159
 160                 foreach (Constant constant in local_constants) {
 161                         constant.active = false;
 162                 }
 163
 164                 // use get_statements () instead of statement_list to not miss errors within StatementList objects
 165                 foreach (Statement stmt in get_statements ()) {
 166                         add_error_types (stmt.get_error_types ());
 167                 }
 168
 169                 context.analyzer.current_symbol = old_symbol;
 170                 context.analyzer.insert_block = old_insert_block;
 171
 172                 return !error;
 173         }
 174
 175         public override void emit (CodeGenerator codegen) {
 176                 codegen.visit_block (this);
 177         }
 178
 179         public void insert_before (Statement stmt, Statement new_stmt) {
 180                 for (int i = 0; i < statement_list.size; i++) {
 181                         var stmt_list = statement_list[i] as StatementList;
 182                         if (stmt_list != null) {
 183                                 for (int j = 0; j < stmt_list.length; j++) {
 184                                         if (stmt_list.get (j) == stmt) {
 185                                                 stmt_list.insert (j, new_stmt);
 186                                                 new_stmt.parent_node = this;
 187                                                 break;
 188                                         }
 189                                 }
 190                         } else if (statement_list[i] == stmt) {
 191                                 stmt_list = new StatementList (source_reference);
 192                                 stmt_list.add (new_stmt);
 193                                 stmt_list.add (stmt);
 194                                 statement_list[i] = stmt_list;
 195                                 new_stmt.parent_node = this;
 196                         }
 197                 }
 198         }
 199
 200         public void replace_statement (Statement old_stmt, Statement new_stmt) {
 201                 for (int i = 0; i < statement_list.size; i++) {
 202                         var stmt_list = statement_list[i] as StatementList;
 203                         if (stmt_list != null) {
 204                                 for (int j = 0; j < stmt_list.length; j++) {
 205                                         if (stmt_list.get (j) == old_stmt) {
 206                                                 stmt_list.set (j, new_stmt);
 207                                                 new_stmt.parent_node = this;
 208                                                 break;
 209                                         }
 210                                 }
 211                         } else if (statement_list[i] == old_stmt) {
 212                                 statement_list[i] = new_stmt;
 213                                 new_stmt.parent_node = this;
 214                                 break;
 215                         }
 216                 }
 217         }
 218 }