root/libcore/Function.h

INCLUDED FROM

// 
//   Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010,
//   2011 Free Software Foundation, Inc
// 
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 3 of the License, or
// (at your option) any later version.
// 
// This program 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 General Public License for more details.
// 
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

#ifndef GNASH_SWF_FUNCTION_H
#define GNASH_SWF_FUNCTION_H

#include <vector>
#include <cassert>
#include <string>

#include "UserFunction.h"
#include "smart_ptr.h"
#include "ObjectURI.h"

// Forward declarations
namespace gnash {
    class action_buffer;
    class as_object;
}

namespace gnash {

class TargetGuard
{
public:

        // @param ch : target to set temporarely
        // @param och : original target to set temporarily
        TargetGuard(as_environment& e, DisplayObject* ch, DisplayObject* och);
        ~TargetGuard();

private:

    as_environment& env;
    DisplayObject* from;
    DisplayObject* from_orig;

};

/// A simple SWF-defined Function
//
/// This represents a callable Function defined in a SWF. The basic version
/// creates a scope in which and 'arguments' array, 'this', 'super', and the
/// expected argument names are defined.
//
/// For a more advanced function, see Function2.
class Function : public UserFunction
{

public:

        typedef std::vector<as_object*> ScopeStack;

        /// \brief
        /// Create an ActionScript function as defined in an
        /// action_buffer starting at offset 'start'
        //
        Function(const action_buffer& ab, as_environment& env, size_t start,
                const ScopeStack& with_stack);

        virtual ~Function() {}

        const ScopeStack& getScopeStack() const {
                return _scopeStack;
        }

        const action_buffer& getActionBuffer() const {
                return _action_buffer;
        }

        size_t getStartPC() const {
                return _startPC;
        }

        size_t getLength() const {
                return _length;
        }

    /// Get the number of registers required for function execution.
    //
    /// For ordinary Functions this is always 0.
    virtual boost::uint8_t registers() const {
        return 0;
    }

    /// Add an expected argument for the function.
    //
    /// For ordinary Functions the register is disregarded. This is only
    /// relevant for Function2s.
    //
    /// All argument names are declared as variables in the function scope,
    /// whether the argument is passed or not.
    //
    /// @param reg      The register for the argument.
    /// @param name     The name of the argument.
        void add_arg(boost::uint8_t reg, const ObjectURI& name) {
        _args.push_back(Argument(reg, name));
        }

    /// Set the length in bytes of the function code.
        void setLength(size_t len);

        /// Dispatch.
        virtual as_value call(const fn_call& fn);

        /// Mark reachable resources. Override from as_object
        //
        /// Reachable resources from this object are its scope stack
        /// and the prototype.
        ///
        virtual void markReachableResources() const;

protected:
        
    struct Argument
        {
        Argument(boost::uint8_t r, const ObjectURI& n) : reg(r), name(n) {}
        boost::uint8_t reg;
        ObjectURI name;
        };

        std::vector<Argument> _args;

        /// @@ might need some kind of ref count here, but beware cycles
        as_environment& _env;

private:

        /// Action buffer containing the function definition
        const action_buffer& _action_buffer;

        /// Scope stack on function definition.
        ScopeStack _scopeStack;

        /// \brief
        /// Offset within the action_buffer where
        /// start of the function is found.
        size_t  _startPC;

        /// Length of the function within the action_buffer
        //
        /// This is currently expressed in bytes as the
        /// action_buffer is just a blocḱ of memory corresponding
        /// to a DoAction block
        size_t _length;


};

/// Add properties to an 'arguments' object.
//
/// The 'arguments' variable is an array with an additional
/// 'callee' member, set to the function being called.
as_object* getArguments(Function& callee, as_object& args, 
        const fn_call& fn, as_object* caller);


} // end of gnash namespace

#endif