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simgear/simgear/nasal/cppbind/Ghost.hxx
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C++

///@file
/// Expose C++ objects to Nasal as ghosts
///
// Copyright (C) 2012 Thomas Geymayer <tomgey@gmail.com>
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Library General Public
// License as published by the Free Software Foundation; either
// version 2 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
// Library General Public License for more details.
//
// You should have received a copy of the GNU Library General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
#ifndef SG_NASAL_GHOST_HXX_
#define SG_NASAL_GHOST_HXX_
#include "NasalCallContext.hxx"
#include "NasalObjectHolder.hxx"
#include <simgear/debug/logstream.hxx>
#include <simgear/std/integer_sequence.hxx>
#include <simgear/std/type_traits.hxx>
#include <simgear/structure/SGWeakReferenced.hxx>
#include <simgear/structure/SGWeakPtr.hxx>
#include <boost/bind.hpp>
#include <boost/call_traits.hpp>
#include <boost/function.hpp>
#include <boost/mpl/has_xxx.hpp>
#include <boost/shared_ptr.hpp>
#include <map>
template<class T>
inline T* get_pointer(boost::weak_ptr<T> const& p)
{
return p.lock().get();
}
template<class T>
inline T* get_pointer(SGWeakPtr<T> const& p)
{
return p.lock().get();
}
namespace osg
{
template<class T>
inline T* get_pointer(observer_ptr<T> const& p)
{
ref_ptr<T> ref;
p.lock(ref);
return ref.get();
}
}
template<class T>
inline std::enable_if_t<std::is_pointer<T>::value, T>
get_pointer(T ptr)
{
return ptr;
}
// Both ways of retrieving the address of a static member function
// should be legal but not all compilers know this.
// g++-4.4.7+ has been tested to work with both versions
#if defined(SG_GCC_VERSION) && SG_GCC_VERSION < 40407
// The old version of g++ used on Jenkins (16.11.2012) only compiles
// this version.
# define SG_GET_TEMPLATE_MEMBER(type, member) &member
// With old g++ on Jenkins (21.07.2014), ADL for static_pointer_cast does not
// work.
using boost::static_pointer_cast;
using osg::static_pointer_cast;
#else
// VS (2008, 2010, ... ?) only allow this version.
# define SG_GET_TEMPLATE_MEMBER(type, member) &type::template member
#endif
/**
* Bindings between C++ and the Nasal scripting language
*/
namespace nasal
{
namespace internal
{
/**
* Metadata for Ghost object types
*/
class GhostMetadata
{
public:
using Deleter = void(*)(void*);
using DestroyList = std::vector<std::pair<Deleter, void*>>;
static DestroyList _destroy_list;
/**
* Add a nasal base class to the ghost. Will be available in the ghosts
* parents array.
*/
void addNasalBase(const naRef& parent);
bool isInstance(naGhostType* ghost_type, bool& is_weak) const;
protected:
const std::string _name_strong,
_name_weak;
const naGhostType *_ghost_type_strong_ptr,
*_ghost_type_weak_ptr;
std::vector<naRef> _parents;
GhostMetadata( const std::string& name,
const naGhostType* ghost_type_strong,
const naGhostType* ghost_type_weak );
void addDerived(const GhostMetadata* derived);
naRef getParents(naContext c);
};
/**
* Hold callable method and convert to Nasal function if required.
*/
class MethodHolder:
public SGWeakReferenced
{
public:
virtual ~MethodHolder() {}
naRef get_naRef(naContext c)
{
if( !_obj.valid() )
_obj.reset(createNasalObject(c));
return _obj.get_naRef();
}
protected:
ObjectHolder<> _obj;
virtual naRef createNasalObject(naContext c) = 0;
};
BOOST_MPL_HAS_XXX_TRAIT_DEF(element_type)
}
/** @brief Destroy all ghost queued for deletion.
*
* This needs can not be done directly during garbage collection, as
* destructors may execute Nasal code which requires creating new Nasal
* contexts. Creating a Nasal context during garbage collection is not
* possible and leads to a dead lock.
*/
void ghostProcessDestroyList();
using MethodHolderPtr = SGSharedPtr<internal::MethodHolder>;
using MethodHolderWeakPtr = SGWeakPtr<internal::MethodHolder>;
// Dummy template to create shorter and easy to understand compile errors if
// trying to wrap the wrong type as a Ghost.
template<class T, class Enable = void>
class Ghost
{
public:
static_assert(
is_strong_ref<T>::value,
"Ghost can only wrap shared pointer!"
);
static Ghost& init(const std::string& name);
static bool isInit();
};
/**
* Class for exposing C++ objects to Nasal
*
* @code{cpp}
* // Example class to be exposed to Nasal
* class MyClass
* {
* public:
* void setX(int x);
* int getX() const;
*
* int myMember();
* void doSomethingElse(const nasal::CallContext& ctx);
* }
* using MyClassPtr = boost::shared_ptr<MyClass>;
*
* std::string myOtherFreeMember(int num);
*
* void exposeClasses()
* {
* // Register a nasal ghost type for MyClass. This needs to be done only
* // once before creating the first ghost instance. The exposed class needs
* // to be wrapped inside a shared pointer, eg. boost::shared_ptr.
* Ghost<MyClassPtr>::init("MyClass")
* // Members can be exposed by getters and setters
* .member("x", &MyClass::getX, &MyClass::setX)
* // For readonly variables only pass a getter
* .member("x_readonly", &MyClass::getX)
* // It is also possible to expose writeonly members
* .member("x_writeonly", &MyClass::setX)
* // Methods can be nearly anything callable and accepting a reference
* // to an instance of the class type. (member functions, free functions
* // and anything else bindable using boost::function and boost::bind)
* .method("myMember", &MyClass::myMember)
* .method("doSomething", &MyClass::doSomethingElse)
* .method("other", &myOtherFreeMember);
* }
* @endcode
*/
template<class T>
class Ghost<T, std::enable_if_t<is_strong_ref<T>::value>>:
public internal::GhostMetadata
{
public:
using raw_type = typename T::element_type;
using strong_ref = typename shared_ptr_traits<T>::strong_ref;
using weak_ref = typename shared_ptr_traits<T>::weak_ref;
using member_func_t = naRef (raw_type::*)(const CallContext&);
using free_func_t = naRef (*)(raw_type&, const CallContext&);
using getter_t = boost::function<naRef(raw_type&, naContext)>;
using setter_t = boost::function<void( raw_type&, naContext, naRef)>;
using method_t = boost::function<naRef(raw_type&, const CallContext&)>;
using fallback_getter_t =
boost::function<bool(raw_type&, naContext, const std::string&, naRef&)>;
using fallback_setter_t =
boost::function<bool(raw_type&, naContext, const std::string&, naRef)>;
template<class Ret, class... Args>
using method_variadic_t = boost::function<Ret (raw_type&, Args...)>;
class MethodHolder:
public internal::MethodHolder
{
public:
explicit MethodHolder(const method_t& method):
_method(method)
{}
protected:
using SharedPtr = SGSharedPtr<MethodHolder>;
using WeakPtr = SGWeakPtr<MethodHolder>;
method_t _method;
virtual naRef createNasalObject(naContext c)
{
return naNewFunc
(
c,
naNewCCodeUD( c,
&MethodHolder::call,
new WeakPtr(this),
&destroyHolder )
);
}
static void destroyHolder(void* user_data)
{
delete static_cast<WeakPtr*>(user_data);
}
static naRef call( naContext c,
naRef me,
int argc,
naRef* args,
void* user_data )
{
WeakPtr* holder_weak = static_cast<WeakPtr*>(user_data);
if( !holder_weak )
naRuntimeError(c, "invalid method holder!");
try
{
SharedPtr holder = holder_weak->lock();
if( !holder )
throw std::runtime_error("holder has expired");
// Keep reference for duration of call to prevent expiring
// TODO not needed for strong referenced ghost
strong_ref ref = fromNasal(c, me);
if( !ref )
{
naGhostType* ghost_type = naGhost_type(me);
naRuntimeError
(
c,
"method called on object of wrong type: "
"is '%s' expected '%s'",
naIsNil(me) ? "nil"
: (ghost_type ? ghost_type->name : "unknown"),
_ghost_type_strong.name
);
}
return holder->_method
(
*get_pointer(ref),
CallContext(c, me, argc, args)
);
}
catch(const std::exception& ex)
{
naRuntimeError(c, "Fatal error in method call: %s", ex.what());
}
catch(...)
{
naRuntimeError(c, "Unknown exception in method call.");
}
return naNil();
}
};
/**
* A ghost member. Can consist either of getter and/or setter functions
* for exposing a data variable or a single callable function.
*/
struct member_t
{
member_t()
{}
member_t( const getter_t& getter,
const setter_t& setter,
const MethodHolderPtr& func = MethodHolderPtr() ):
getter( getter ),
setter( setter ),
func( func )
{}
explicit member_t(const MethodHolderPtr& func):
func( func )
{}
getter_t getter;
setter_t setter;
MethodHolderPtr func;
};
using MemberMap = std::map<std::string, member_t>;
/**
* Register a new ghost type.
*
* @note Only intialize each ghost type once!
*
* @param name Descriptive name of the ghost type.
*/
static Ghost& init(const std::string& name)
{
getSingletonHolder().reset( new Ghost(name) );
return *getSingletonPtr();
}
/**
* Check whether ghost type has already been initialized.
*/
static bool isInit()
{
return getSingletonPtr();
}
/**
* Register a base class for this ghost. The base class needs to be
* registers on its own before it can be used as base class.
*
* @tparam BaseGhost Type of base class already wrapped into Ghost class
* (Ghost<BasePtr>)
*
* @code{cpp}
* Ghost<MyBasePtr>::init("MyBase");
* Ghost<MyClassPtr>::init("MyClass")
* .bases<Ghost<MyBasePtr> >();
* @endcode
*/
template<class BaseGhost>
std::enable_if_t<
std::is_base_of<GhostMetadata, BaseGhost>::value,
Ghost&
>
bases()
{
static_assert(
std::is_base_of<typename BaseGhost::raw_type, raw_type>::value,
"Not a base class!"
);
using base_ref = typename BaseGhost::strong_ref;
BaseGhost* base = BaseGhost::getSingletonPtr();
base->addDerived(
this,
SG_GET_TEMPLATE_MEMBER(Ghost, toNasal<BaseGhost>),
SG_GET_TEMPLATE_MEMBER(Ghost, fromNasalWithCast<base_ref>)
);
// Replace any getter that is not available in the current class.
// TODO check if this is the correct behavior of function overriding
for(auto const& base_member: base->_members)
{
if( _members.find(base_member.first) == _members.end() )
_members[base_member.first] = member_t
(
base_member.second.getter,
base_member.second.setter,
base_member.second.func
);
}
if( !_fallback_setter )
_fallback_setter = base->_fallback_setter;
if( !_fallback_getter )
_fallback_getter = base->_fallback_getter;
return *this;
}
/**
* Register a base class for this ghost. The base class needs to be
* registers on its own before it can be used as base class.
*
* @tparam Base Type of base class (Base as used in Ghost<BasePtr>)
*
* @code{cpp}
* Ghost<MyBasePtr>::init("MyBase");
* Ghost<MyClassPtr>::init("MyClass")
* .bases<MyBasePtr>();
* @endcode
*/
template<class Base>
std::enable_if_t<
!std::is_base_of<GhostMetadata, Base>::value,
Ghost&
>
bases()
{
static_assert(
std::is_base_of<typename Ghost<Base>::raw_type, raw_type>::value,
"Not a base class!"
);
return bases< Ghost<Base> >();
}
/**
* Register an existing Nasal class/hash as base class for this ghost.
*
* @param parent Nasal hash/class
*/
Ghost& bases(const naRef& parent)
{
addNasalBase(parent);
return *this;
}
/**
* Register a member variable by passing a getter and/or setter method.
*
* @param field Name of member
* @param getter Getter for variable
* @param setter Setter for variable (Pass 0 to prevent write access)
*
*/
template<class Ret, class Param>
Ghost& member( const std::string& field,
Ret (raw_type::*getter)() const,
void (raw_type::*setter)(Param) )
{
return member(field, to_getter(getter), to_setter(setter));
}
template<class Param>
Ghost& member( const std::string& field,
const getter_t& getter,
void (raw_type::*setter)(Param) )
{
return member(field, getter, to_setter(setter));
}
template<class Ret>
Ghost& member( const std::string& field,
Ret (raw_type::*getter)() const,
const setter_t& setter )
{
return member(field, to_getter(getter), setter);
}
/**
* Register a read only member variable.
*
* @param field Name of member
* @param getter Getter for variable
*/
template<class Ret>
Ghost& member( const std::string& field,
Ret (raw_type::*getter)() const )
{
return member(field, to_getter(getter), setter_t());
}
Ghost& member( const std::string& field,
naRef (*getter)(const raw_type&, naContext) )
{
return member(field, getter_t(getter), setter_t());
}
Ghost& member( const std::string& field,
naRef (*getter)(raw_type&, naContext) )
{
return member(field, getter_t(getter), setter_t());
}
/**
* Register a write only member variable.
*
* @param field Name of member
* @param setter Setter for variable
*/
template<class Var>
Ghost& member( const std::string& field,
void (raw_type::*setter)(Var) )
{
return member(field, getter_t(), to_setter(setter));
}
Ghost& member( const std::string& field,
void (*setter)(raw_type&, naContext, naRef) )
{
return member(field, getter_t(), setter_t(setter));
}
Ghost& member( const std::string& field,
const setter_t& setter )
{
return member(field, getter_t(), setter);
}
/**
* Register a member variable by passing a getter and/or setter method.
*
* @param field Name of member
* @param getter Getter for variable
* @param setter Setter for variable (Pass empty to prevent write access)
*
*/
Ghost& member( const std::string& field,
const getter_t& getter,
const setter_t& setter = setter_t() )
{
if( !getter.empty() || !setter.empty() )
_members[field] = member_t(getter, setter);
else
SG_LOG
(
SG_NASAL,
SG_WARN,
"Member '" << field << "' requires a getter or setter"
);
return *this;
}
/**
* Register a function which is called upon retrieving an unknown member
* of this ghost.
*/
Ghost& _get(const fallback_getter_t& getter)
{
_fallback_getter = getter;
return *this;
}
/**
* Register a function which is called upon retrieving an unknown member
* of this ghost, and convert it to the given @a Param type.
*/
template<class Param>
Ghost& _get( const boost::function<bool ( raw_type&,
const std::string&,
Param& )>& getter )
{
return _get(boost::bind(
convert_param_invoker<Param>, getter, _1, _2, _3, _4
));
}
/**
* Register a method which is called upon retrieving an unknown member of
* this ghost.
*
* @code{cpp}
* class MyClass
* {
* public:
* bool getMember( const std::string& key,
* std::string& value_out ) const;
* }
*
* Ghost<MyClassPtr>::init("Test")
* ._get(&MyClass::getMember);
* @endcode
*/
template<class Param>
Ghost& _get(bool (raw_type::*getter)(const std::string&, Param&) const)
{
return _get(
boost::function<bool (raw_type&, const std::string&, Param&)>(getter)
);
}
/**
* Register a method which is called upon retrieving an unknown member of
* this ghost.
*
* @code{cpp}
* class MyClass
* {
* public:
* bool getMember( naContext c,
* const std::string& key,
* naRef& value_out );
* }
*
* Ghost<MyClassPtr>::init("Test")
* ._get(&MyClass::getMember);
* @endcode
*/
Ghost& _get(bool (raw_type::*getter)( naContext,
const std::string&,
naRef& ) const)
{
return _get( fallback_getter_t(getter) );
}
/**
* Register a function which is called upon setting an unknown member of
* this ghost.
*/
Ghost& _set(const fallback_setter_t& setter)
{
_fallback_setter = setter;
return *this;
}
/**
* Register a function which is called upon setting an unknown member of
* this ghost, and convert it to the given @a Param type.
*/
template<class Param>
Ghost& _set(const boost::function<bool ( raw_type&,
const std::string&,
Param )>& setter)
{
// Setter signature: bool( raw_type&,
// naContext,
// const std::string&,
// naRef )
return _set(boost::bind(
setter,
_1,
_3,
boost::bind(from_nasal_ptr<Param>::get(), _2, _4)
));
}
/**
* Register a method which is called upon setting an unknown member of
* this ghost.
*
* @code{cpp}
* class MyClass
* {
* public:
* bool setMember( const std::string& key,
* const std::string& value );
* }
*
* Ghost<MyClassPtr>::init("Test")
* ._set(&MyClass::setMember);
* @endcode
*/
template<class Param>
Ghost& _set(bool (raw_type::*setter)(const std::string&, Param))
{
return _set(
boost::function<bool (raw_type&, const std::string&, Param)>(setter)
);
}
/**
* Register a method which is called upon setting an unknown member of
* this ghost.
*
* @code{cpp}
* class MyClass
* {
* public:
* bool setMember( naContext c,
* const std::string& key,
* naRef value );
* }
*
* Ghost<MyClassPtr>::init("Test")
* ._set(&MyClass::setMember);
* @endcode
*/
Ghost& _set(bool (raw_type::*setter)( naContext,
const std::string&,
naRef ))
{
return _set( fallback_setter_t(setter) );
}
/**
* Register anything that accepts an object instance and a
* nasal::CallContext and returns naRef as method.
*
* @code{cpp}
* class MyClass
* {
* public:
* naRef myMethod(const nasal::CallContext& ctx);
* }
*
* Ghost<MyClassPtr>::init("Test")
* .method("myMethod", &MyClass::myMethod);
* @endcode
*/
Ghost& method(const std::string& name, const method_t& func)
{
_members[name].func = new MethodHolder(func);
return *this;
}
/**
* Register anything that accepts an object instance and a
* nasal::CallContext with automatic conversion of the return type to
* Nasal.
*
* @code{cpp}
* class MyClass;
* void doIt(const MyClass& c, const nasal::CallContext& ctx);
*
* Ghost<MyClassPtr>::init("Test")
* .method("doIt", &doIt);
* @endcode
*/
template<class Ret>
Ghost& method
(
const std::string& name,
const boost::function<Ret (raw_type&, const CallContext&)>& func
)
{
return method(name, boost::bind(method_invoker<Ret>, func, _1, _2));
}
/**
* Bind any callable entity accepting an instance of raw_type and an
* arbitrary number of arguments as method.
*
* The std::index_sequence specifies the order of the arguments
*/
template<class Ret, class... Args, std::size_t... Indices>
Ghost& method( const std::string& name,
const method_variadic_t<Ret, Args...>& func,
std::index_sequence<Indices...> )
{
return method<Ret>
(
name,
typename boost::function<Ret (raw_type&, const CallContext&)>
( boost::bind(
func,
_1,
boost::bind(&Ghost::arg_from_nasal<Args>, _2, Indices)...
))
);
}
template<class Ret, class... Args>
Ghost& method( const std::string& name,
const method_variadic_t<Ret, Args...>& func )
{
return method(name, func, std::index_sequence_for<Args...>{});
}
/**\
* Bind a member function with an arbitrary number of arguments as method.
*/
template<class Ret, class... Args>
Ghost& method( const std::string& name,
Ret (raw_type::*fn)(Args...) )
{
return method(name, method_variadic_t<Ret, Args...>(fn));
}
template<class Ret, class... Args>
Ghost& method( const std::string& name,
Ret (raw_type::*fn)(Args...) const )
{
return method(name, method_variadic_t<Ret, Args...>(fn));
}
/**
* Bind free function accepting an instance of raw_type and an arbitrary
* number of arguments as method.
*/
template<class Ret, class Type, class... Args>
Ghost& method
(
const std::string& name,
Ret (*fn)(Type, Args ... args)
)
{
static_assert(
std::is_convertible<raw_type&, Type>::value,
//|| std::is_convertible<raw_type*, Type>::value
// TODO check how to do it with pointer...
"First parameter can not be converted from the Ghost raw_type!"
);
return method(name, method_variadic_t<Ret, Args...>(fn));
}
/**
* Create a shared pointer on the heap to handle the reference counting
* for the passed shared pointer while it is used in Nasal space.
*/
template<class RefType>
static
std::enable_if_t<
std::is_same<RefType, strong_ref>::value
|| std::is_same<RefType, weak_ref>::value,
naRef
>
makeGhost(naContext c, RefType const& ref_ptr)
{
strong_ref ref(ref_ptr);
raw_type* ptr = get_pointer(ref);
if( !ptr )
return naNil();
// We are wrapping shared pointers to already existing objects which
// will then be hold be a new shared pointer. We therefore have to
// check for the dynamic type of the object as it might differ from
// the passed static type.
return toNasal<Ghost>(
c,
ref,
shared_ptr_traits<RefType>::is_strong::value
);
}
/**
* Convert Nasal object to C++ object. To get a valid object the passed
* Nasal objects has to be derived class of the target class (Either
* derived in C++ or in Nasal using a 'parents' vector)
*/
static strong_ref fromNasal(naContext c, naRef me)
{
naGhostType* ghost_type = naGhost_type(me);
if( ghost_type )
{
// Check if we got an instance of this class
bool is_weak = false;
if( isInstance(ghost_type, is_weak) )
{
return is_weak ? getPtr<strong_ref, true>(naGhost_ptr(me))
: getPtr<strong_ref, false>(naGhost_ptr(me));
}
// otherwise try the derived classes
for( auto derived = getSingletonPtr()->_derived_types.rbegin();
derived != getSingletonPtr()->_derived_types.rend();
++derived )
{
strong_ref ref = (derived->from_nasal)(c, me);
if( get_pointer(ref) )
return ref;
}
}
else if( naIsHash(me) )
{
naRef na_parents = naHash_cget(me, const_cast<char*>("parents"));
if( !naIsVector(na_parents) )
return strong_ref();
auto parents = from_nasal<std::vector<naRef>>(c, na_parents);
for(auto parent: parents)
{
strong_ref ref = fromNasal(c, parent);
if( get_pointer(ref) )
return ref;
}
}
return strong_ref();
}
/**
* Convert Nasal object to C++ object and check if it has the correct
* type.
*
* @see fromNasal
*/
static strong_ref fromNasalChecked(naContext c, naRef me)
{
strong_ref obj = fromNasal(c, me);
if( obj )
return obj;
if( naIsNil(me) )
return strong_ref();
std::string msg = "Can not convert to '"
+ getSingletonPtr()->_name_strong
+ "': ";
naGhostType* ghost_type = naGhost_type(me);
if( ghost_type )
msg += "not a derived class (or expired weak ref): "
"'" + std::string(ghost_type->name) + "'";
else if( naIsHash(me) )
{
if( !naIsVector(naHash_cget(me, const_cast<char*>("parents"))) )
msg += "missing parents vector";
else
msg += "not a derived hash";
}
else
msg += "not an object";
throw bad_nasal_cast(msg);
}
private:
template<class, class>
friend class Ghost;
static naGhostType _ghost_type_strong, //!< Stored as shared pointer
_ghost_type_weak; //!< Stored as weak shared pointer
using to_nasal_t = naRef (*)(naContext, const strong_ref&, bool);
using from_nasal_t = strong_ref (*)(naContext, naRef);
struct DerivedInfo
{
to_nasal_t to_nasal;
from_nasal_t from_nasal;
DerivedInfo( to_nasal_t to_nasal_func,
from_nasal_t from_nasal_func ):
to_nasal(to_nasal_func),
from_nasal(from_nasal_func)
{}
};
using DerivedList = std::vector<DerivedInfo>;
DerivedList _derived_types;
static bool isInstance(naGhostType* ghost_type, bool& is_weak)
{
if( !ghost_type || !getSingletonPtr() )
return false;
return getSingletonPtr()->GhostMetadata::isInstance( ghost_type,
is_weak );
}
template<class RefPtr, bool is_weak>
static
std::enable_if_t<!is_weak, RefPtr>
getPtr(void* ptr)
{
using storage_type = shared_ptr_storage<strong_ref>;
if( ptr )
return storage_type::template get<RefPtr>(
static_cast<typename storage_type::storage_type*>(ptr)
);
else
return RefPtr();
}
template<class RefPtr, bool is_weak>
static
std::enable_if_t<
is_weak && supports_weak_ref<T>::value,
RefPtr
>
getPtr(void* ptr)
{
using storage_type = shared_ptr_storage<weak_ref>;
if( ptr )
return storage_type::template get<RefPtr>(
static_cast<typename storage_type::storage_type*>(ptr)
);
else
return RefPtr();
}
template<class RefPtr, bool is_weak>
static
std::enable_if_t<
is_weak && !supports_weak_ref<T>::value,
RefPtr
>
getPtr(void* ptr)
{
return RefPtr();
}
void addDerived( const internal::GhostMetadata* derived_meta,
to_nasal_t to_nasal_func,
from_nasal_t from_nasal_func )
{
GhostMetadata::addDerived(derived_meta);
_derived_types.push_back(DerivedInfo(to_nasal_func, from_nasal_func));
}
template<class BaseGhost>
static
std::enable_if_t<
std::is_polymorphic<typename BaseGhost::raw_type>::value,
naRef
>
toNasal( naContext c,
const typename BaseGhost::strong_ref& base_ref,
bool strong )
{
typename BaseGhost::raw_type* ptr = get_pointer(base_ref);
// Check first if passed pointer can by converted to instance of class
// this ghost wraps.
if( !std::is_same<
typename BaseGhost::raw_type,
typename Ghost::raw_type
>::value
&& dynamic_cast<const typename Ghost::raw_type*>(ptr) != ptr )
return naNil();
if( !getSingletonPtr() )
{
SG_LOG
(
SG_NASAL,
SG_INFO,
"Ghost::getTypeFor: can not get type for unregistered ghost"
);
return naNil();
}
strong_ref ref =
static_pointer_cast<typename Ghost::raw_type>(base_ref);
// Now check if we can further downcast to one of our derived classes.
for( auto derived = getSingletonPtr()->_derived_types.rbegin();
derived != getSingletonPtr()->_derived_types.rend();
++derived )
{
naRef ghost = (derived->to_nasal)(c, ref, strong);
if( !naIsNil(ghost) )
return ghost;
}
// If base is not an instance of any derived class, this class has to
// be the dynamic type.
return strong
? create<false>(c, ref)
: create<true>(c, ref);
}
template<class BaseGhost>
static
std::enable_if_t<
!std::is_polymorphic<typename BaseGhost::raw_type>::value,
naRef
>
toNasal( naContext c,
const typename BaseGhost::strong_ref& ref,
bool strong )
{
// For non polymorphic classes there is no possibility to get the actual
// dynamic type, therefore we can only use its static type.
return strong
? create<false>(c, ref)
: create<true>(c, ref);
}
template<class Type>
static Type fromNasalWithCast(naContext c, naRef me)
{
return Type(fromNasal(c, me));
}
static Ghost* getSingletonPtr()
{
return getSingletonHolder().get();
}
template<class Ret>
getter_t to_getter(Ret (raw_type::*getter)() const)
{
using param_type = typename boost::call_traits<Ret>::param_type;
naRef(*to_nasal_)(naContext, param_type) = &to_nasal;
// Getter signature: naRef(raw_type&, naContext)
return boost::bind
(
to_nasal_,
_2,
boost::bind(getter, _1)
);
}
template<class Param>
setter_t to_setter(void (raw_type::*setter)(Param))
{
// Setter signature: void(raw_type&, naContext, naRef)
return boost::bind
(
setter,
_1,
boost::bind(from_nasal_ptr<Param>::get(), _2, _3)
);
}
/**
* Invoke a method which writes the converted parameter to a reference
*/
template<class Param>
static
bool convert_param_invoker
(
const boost::function<bool ( raw_type&,
const std::string&,
Param& )>& func,
raw_type& obj,
naContext c,
const std::string& key,
naRef& out
)
{
Param p;
if( !func(obj, key, p) )
return false;
out = to_nasal(c, p);
return true;
};
/**
* Invoke a method which returns a value and convert it to Nasal.
*/
template<class Ret>
static
std::enable_if_t<!std::is_void<Ret>::value, naRef>
method_invoker
(
const boost::function<Ret (raw_type&, const CallContext&)>& func,
raw_type& obj,
const CallContext& ctx
)
{
return (*to_nasal_ptr<Ret>::get())(ctx.c_ctx(), func(obj, ctx));
};
/**
* Invoke a method which returns void and "convert" it to nil.
*/
template<class Ret>
static
std::enable_if_t<std::is_void<Ret>::value, naRef>
method_invoker
(
const boost::function<Ret (raw_type&, const CallContext&)>& func,
raw_type& obj,
const CallContext& ctx
)
{
func(obj, ctx);
return naNil();
};
/**
* Extract argument by index from nasal::CallContext and convert to given
* type.
*/
template<class Arg>
static
std::enable_if_t<
!std::is_same<std::remove_cvref_t<Arg>, CallContext>::value,
typename from_nasal_ptr<Arg>::return_type
>
arg_from_nasal(const CallContext& ctx, size_t index)
{
return ctx.requireArg<Arg>(index);
};
/**
* Specialization to pass through nasal::CallContext.
*/
template<class Arg>
static
std::enable_if_t<
std::is_same<std::remove_cvref_t<Arg>, CallContext>::value,
typename from_nasal_ptr<Arg>::return_type
>
arg_from_nasal(const CallContext& ctx, size_t)
{
// Either const CallContext& or CallContext, non-const reference
// does not make sense.
static_assert(
!boost::is_same<Arg, CallContext&>::value,
"Only const reference and value make sense!");
return ctx;
};
using GhostPtr = std::unique_ptr<Ghost>;
MemberMap _members;
fallback_getter_t _fallback_getter;
fallback_setter_t _fallback_setter;
explicit Ghost(const std::string& name):
GhostMetadata( name,
&_ghost_type_strong,
supports_weak_ref<T>::value ? &_ghost_type_weak : NULL )
{
_ghost_type_strong.destroy =
SG_GET_TEMPLATE_MEMBER(Ghost, queueDestroy<strong_ref>);
_ghost_type_strong.name = _name_strong.c_str();
_ghost_type_strong.get_member = &Ghost::getMemberStrong;
_ghost_type_strong.set_member = &Ghost::setMemberStrong;
_ghost_type_weak.destroy =
SG_GET_TEMPLATE_MEMBER(Ghost, queueDestroy<weak_ref>);
_ghost_type_weak.name = _name_weak.c_str();
if( supports_weak_ref<T>::value )
{
_ghost_type_weak.get_member = &Ghost::getMemberWeak;
_ghost_type_weak.set_member = &Ghost::setMemberWeak;
}
else
{
_ghost_type_weak.get_member = 0;
_ghost_type_weak.set_member = 0;
}
}
static GhostPtr& getSingletonHolder()
{
static GhostPtr instance;
return instance;
}
template<bool is_weak>
static
std::enable_if_t<!is_weak, naRef>
create(naContext c, const strong_ref& ref_ptr)
{
using storage_type = shared_ptr_storage<strong_ref>;
return naNewGhost2( c,
&Ghost::_ghost_type_strong,
storage_type::ref(ref_ptr) );
}
template<bool is_weak>
static
std::enable_if_t<
is_weak && supports_weak_ref<T>::value,
naRef
>
create(naContext c, const strong_ref& ref_ptr)
{
using storage_type = shared_ptr_storage<weak_ref>;
return naNewGhost2( c,
&Ghost::_ghost_type_weak,
storage_type::ref(ref_ptr) );
}
template<bool is_weak>
static
std::enable_if_t<
is_weak && !supports_weak_ref<T>::value,
naRef
>
create(naContext, const strong_ref&)
{
return naNil();
}
template<class Type>
static void destroy(void *ptr)
{
using storage_type = shared_ptr_storage<Type>;
storage_type::unref(
static_cast<typename storage_type::storage_type*>(ptr)
);
}
template<class Type>
static void queueDestroy(void *ptr)
{
_destroy_list.push_back( DestroyList::value_type(&destroy<Type>, ptr) );
}
static void raiseErrorExpired(naContext c, const char* str)
{
Ghost* ghost_info = getSingletonPtr();
naRuntimeError(
c,
"Ghost::%s: ghost has expired '%s'",
str,
ghost_info ? ghost_info->_name_strong.c_str() : "unknown"
);
}
/**
* Callback for retrieving a ghost member.
*/
static const char* getMemberImpl( naContext c,
raw_type& obj,
naRef key,
naRef* out )
{
const std::string key_str = nasal::from_nasal<std::string>(c, key);
// TODO merge instance parents with static class parents
// if( key_str == "parents" )
// {
// if( getSingletonPtr()->_parents.empty() )
// return 0;
//
// *out = getSingletonPtr()->getParents(c);
// return "";
// }
auto member = getSingletonPtr()->_members.find(key_str);
if( member == getSingletonPtr()->_members.end() )
{
fallback_getter_t fallback_get = getSingletonPtr()->_fallback_getter;
if( !fallback_get
|| !fallback_get(obj, c, key_str, *out) )
return 0;
}
else if( member->second.func )
*out = member->second.func->get_naRef(c);
else if( !member->second.getter.empty() )
*out = member->second.getter(obj, c);
else
return "Read-protected member";
return "";
}
static const char*
getMemberWeak(naContext c, void* ghost, naRef key, naRef* out)
{
// Keep a strong reference while retrieving member, to prevent deleting
// object in between.
strong_ref ref = getPtr<strong_ref, true>(ghost);
if( !ref )
raiseErrorExpired(c, "getMember");
return getMemberImpl(c, *get_pointer(ref), key, out);
}
static const char*
getMemberStrong(naContext c, void* ghost, naRef key, naRef* out)
{
// Just get a raw pointer as we are keeping a strong reference as ghost
// anyhow.
raw_type* ptr = getPtr<raw_type*, false>(ghost);
return getMemberImpl(c, *ptr, key, out);
}
/**
* Callback for writing to a ghost member.
*/
static void setMemberImpl( naContext c,
raw_type& obj,
naRef field,
naRef val )
{
const std::string key = nasal::from_nasal<std::string>(c, field);
const MemberMap& members = getSingletonPtr()->_members;
auto member = members.find(key);
if( member == members.end() )
{
fallback_setter_t fallback_set = getSingletonPtr()->_fallback_setter;
if( !fallback_set )
naRuntimeError(c, "ghost: No such member: %s", key.c_str());
else if( !fallback_set(obj, c, key, val) )
naRuntimeError(c, "ghost: Failed to write (_set: %s)", key.c_str());
}
else if( member->second.setter.empty() )
naRuntimeError(c, "ghost: Write protected member: %s", key.c_str());
else if( member->second.func )
naRuntimeError(c, "ghost: Write to function: %s", key.c_str());
else
member->second.setter(obj, c, val);
}
static void
setMemberWeak(naContext c, void* ghost, naRef field, naRef val)
{
// Keep a strong reference while retrieving member, to prevent deleting
// object in between.
strong_ref ref = getPtr<strong_ref, true>(ghost);
if( !ref )
raiseErrorExpired(c, "setMember");
setMemberImpl(c, *get_pointer(ref), field, val);
}
static void
setMemberStrong(naContext c, void* ghost, naRef field, naRef val)
{
// Just get a raw pointer as we are keeping a strong reference as ghost
// anyhow.
raw_type* ptr = getPtr<raw_type*, false>(ghost);
setMemberImpl(c, *ptr, field, val);
}
};
template<class T>
naGhostType
Ghost<T, std::enable_if_t<is_strong_ref<T>::value>>::_ghost_type_strong;
template<class T>
naGhostType
Ghost<T, std::enable_if_t<is_strong_ref<T>::value>>::_ghost_type_weak;
} // namespace nasal
// Needs to be outside any namespace to make ADL work
/**
* Convert every shared pointer to a ghost.
*/
template<class T>
std::enable_if_t<
nasal::internal::has_element_type<std::remove_cvref_t<T>>::value,
naRef
>
to_nasal_helper(naContext c, T ptr)
{
using strong_ref = typename nasal::shared_ptr_traits<T>::strong_ref;
return nasal::Ghost<strong_ref>::makeGhost(c, ptr);
}
/**
* Convert nasal ghosts/hashes to shared pointer (of a ghost).
*/
template<class T>
std::enable_if_t<
nasal::internal::has_element_type<std::remove_cvref_t<T>>::value,
T
>
from_nasal_helper(naContext c, naRef ref, const T*)
{
using strong_ref = typename nasal::shared_ptr_traits<T>::strong_ref;
return T(nasal::Ghost<strong_ref>::fromNasalChecked(c, ref));
}
/**
* Convert any pointer to a SGReferenced based object to a ghost.
*/
template<class T>
std::enable_if_t<
std::is_base_of<SGReferenced, T>::value
|| std::is_base_of<SGWeakReferenced, T>::value,
naRef
>
to_nasal_helper(naContext c, T* ptr)
{
return nasal::Ghost<SGSharedPtr<T> >::makeGhost(c, SGSharedPtr<T>(ptr));
}
/**
* Convert nasal ghosts/hashes to pointer (of a SGReferenced based ghost).
*/
template<class T>
std::enable_if_t<
std::is_base_of<SGReferenced, std::remove_pointer_t<T>>::value
|| std::is_base_of<SGWeakReferenced, std::remove_pointer_t<T>>::value,
T
>
from_nasal_helper(naContext c, naRef ref, const T*)
{
using TypeRef = SGSharedPtr<std::remove_pointer_t<T>>;
return T(nasal::Ghost<TypeRef>::fromNasalChecked(c, ref));
}
/**
* Convert any pointer to a osg::Referenced based object to a ghost.
*/
template<class T>
std::enable_if_t<
std::is_base_of<osg::Referenced, T>::value,
naRef
>
to_nasal_helper(naContext c, T* ptr)
{
return nasal::Ghost<osg::ref_ptr<T> >::makeGhost(c, osg::ref_ptr<T>(ptr));
}
/**
* Convert nasal ghosts/hashes to pointer (of a osg::Referenced based ghost).
*/
template<class T>
std::enable_if_t<
std::is_base_of<osg::Referenced, std::remove_pointer_t<T>>::value,
T
>
from_nasal_helper(naContext c, naRef ref, const T*)
{
using TypeRef = osg::ref_ptr<std::remove_pointer_t<T>>;
return T(nasal::Ghost<TypeRef>::fromNasalChecked(c, ref));
}
#endif /* SG_NASAL_GHOST_HXX_ */