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[vala-lang.git] / vala / valasignal.vala

/* valasignal.vala
 *
 * Copyright (C) 2006-2010  Jürg Billeter
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.

 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.

 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301  USA
 *
 * Author:
 *      Jürg Billeter <j@bitron.ch>
 */

using GLib;

/**
 * Represents an object signal. Signals enable objects to provide notifications.
 */
public class Vala.Signal : Symbol, Lockable {
        /**
         * The return type of handlers of this signal.
         */
        public DataType return_type {
                get { return _return_type; }
                set {
                        _return_type = value;
                        _return_type.parent_node = this;
                }
        }

        public Block body {
                get { return _body; }
                set {
                        _body = value;
                        if (_body != null) {
                                _body.owner = scope;
                        }
                }
        }

        /**
         * Specifies whether this signal has an emitter wrapper function.
         */
        public bool has_emitter { get; set; }
        
        /**
         * Specifies whether this signal has virtual method handler.
         */
        public bool is_virtual { get; set; }

        private List<Parameter> parameters = new ArrayList<Parameter> ();
        /**
         * Refers to the default signal handler, which is an anonymous
         * function in the scope.
         * */
        public Method default_handler { get; private set; }

        public bool is_detailed { get; set; }

        public bool no_recurse { get; set; }

        public string run_type { get; set; }

        public bool is_action { get; set; }

        public bool no_hooks { get; set; }


        private string cname;
        
        private bool lock_used = false;

        private DataType _return_type;

        private Block _body;

        /**
         * Creates a new signal.
         *
         * @param name        signal name
         * @param return_type signal return type
         * @param source      reference to source code
         * @return            newly created signal
         */
        public Signal (string name, DataType return_type, SourceReference? source_reference = null, Comment? comment = null) {
                base (name, source_reference, comment);
                this.return_type = return_type;
                this.run_type = "last";
        }
        
        /**
         * Appends parameter to signal handler.
         *
         * @param param a formal parameter
         */
        public void add_parameter (Parameter param) {
                // default C parameter position
                param.cparameter_position = parameters.size + 1;
                param.carray_length_parameter_position = param.cparameter_position + 0.1;
                param.cdelegate_target_parameter_position = param.cparameter_position + 0.1;
                param.cdestroy_notify_parameter_position = param.cparameter_position + 0.1;

                parameters.add (param);
                scope.add (param.name, param);
        }

        public List<Parameter> get_parameters () {
                return parameters;
        }

        /**
         * Returns generated delegate to be used for signal handlers.
         *
         * @return delegate
         */
        public Delegate get_delegate (DataType sender_type, CodeNode node_reference) {
                var actual_return_type = return_type.get_actual_type (sender_type, null, node_reference);

                var generated_delegate = new Delegate (null, actual_return_type);
                generated_delegate.has_target = true;
                generated_delegate.access = SymbolAccessibility.PUBLIC;
                generated_delegate.owner = scope;

                // sender parameter is never null and doesn't own its value
                var sender_param_type = sender_type.copy ();
                sender_param_type.value_owned = false;
                sender_param_type.nullable = false;

                generated_delegate.sender_type = sender_param_type;

                foreach (Parameter param in parameters) {
                        var actual_param = param.copy ();
                        actual_param.variable_type = actual_param.variable_type.get_actual_type (sender_type, null, node_reference);
                        generated_delegate.add_parameter (actual_param);
                }

                scope.add (null, generated_delegate);

                return generated_delegate;
        }

        /**
         * Returns the name of this signal as it is used in C code.
         *
         * @return the name to be used in C code
         */
        public string get_cname () {
                if (cname == null) {
                        cname = camel_case_to_lower_case (name);
                }
                return cname;
        }
        
        public void set_cname (string cname) {
                this.cname = cname;
        }
        
        /**
         * Returns the string literal of this signal to be used in C code.
         *
         * @return string literal to be used in C code
         */
        public CCodeConstant get_canonical_cconstant (string? detail = null) {
                var str = new StringBuilder ("\"");
                
                string i = get_cname ();
                
                while (i.length > 0) {
                        unichar c = i.get_char ();
                        if (c == '_') {
                                str.append_c ('-');
                        } else {
                                str.append_unichar (c);
                        }
                        
                        i = i.next_char ();
                }

                if (detail != null) {
                        str.append ("::");
                        str.append (detail);
                }

                str.append_c ('"');
                
                return new CCodeConstant (str.str);
        }

        public override void accept (CodeVisitor visitor) {
                visitor.visit_signal (this);
        }

        public override void accept_children (CodeVisitor visitor) {
                return_type.accept (visitor);
                
                foreach (Parameter param in parameters) {
                        param.accept (visitor);
                }
                if (default_handler == null && body != null) {
                        body.accept (visitor);
                } else if (default_handler != null) {
                        default_handler.accept (visitor);
                }
        }

        void process_signal_attribute (Attribute a) {
                if (a.has_argument ("detailed")) {
                        is_detailed = a.get_bool ("detailed");
                }
                if (a.has_argument ("no_recurse")) {
                        no_recurse = a.get_bool ("no_recurse");
                }
                if (a.has_argument ("run")) {
                        var arg = a.get_string ("run");
                        if (arg == "first") {
                                run_type = "first";
                        } else if (arg == "last") {
                                run_type = "last";
                        } else if (arg == "cleanup") {
                                run_type = "cleanup";
                        }
                }

                if (a.has_argument ("action")) {
                        is_action = a.get_bool ("action");
                }

                if (a.has_argument ("no_hooks")) {
                        no_hooks = a.get_bool ("no_hooks");
                }
        }

        /**
         * Process all associated attributes.
         */
        public void process_attributes () {
                foreach (Attribute a in attributes) {
                        if (a.name == "HasEmitter") {
                                has_emitter = true;
                        } else if (a.name == "Signal") {
                                process_signal_attribute (a);
                        } else if (a.name == "Deprecated") {
                                process_deprecated_attribute (a);
                        }
                }
        }
        
        public bool get_lock_used () {
                return lock_used;
        }
        
        public void set_lock_used (bool used) {
                lock_used = used;
        }

        public override void replace_type (DataType old_type, DataType new_type) {
                if (return_type == old_type) {
                        return_type = new_type;
                }
        }

        public override bool check (CodeContext context) {
                if (checked) {
                        return !error;
                }

                checked = true;

                process_attributes ();

                return_type.check (context);
                
                foreach (Parameter param in parameters) {
                        param.check (context);
                }

                if (!is_virtual && body != null) {
                        Report.error (source_reference, "Only virtual signals can have a default signal handler body");
                }


                if (is_virtual) {
                        default_handler = new Method (name, return_type, source_reference);

                        default_handler.owner = owner;
                        default_handler.access = access;
                        default_handler.external = external;
                        default_handler.is_virtual = true;
                        default_handler.vfunc_name = name;
                        default_handler.signal_reference = this;
                        default_handler.body = body;


                        foreach (Parameter param in parameters) {
                                default_handler.add_parameter (param);
                        }

                        var cl = parent_symbol as ObjectTypeSymbol;

                        cl.add_hidden_method (default_handler);
                        default_handler.check (context);
                }


                if (!external_package && !hides && get_hidden_member () != null) {
                        Report.warning (source_reference, "%s hides inherited signal `%s'. Use the `new' keyword if hiding was intentional".printf (get_full_name (), get_hidden_member ().get_full_name ()));
                }

                return !error;
        }
}