ceph/src/boost/boost/python/object/py_function.hpp

   1 // Copyright David Abrahams 2002.
   2 // Distributed under the Boost Software License, Version 1.0. (See
   3 // accompanying file LICENSE_1_0.txt or copy at
   4 // http://www.boost.org/LICENSE_1_0.txt)
   5 #ifndef PY_FUNCTION_DWA200286_HPP
   6 # define PY_FUNCTION_DWA200286_HPP
   7
   8 # include <boost/python/detail/signature.hpp>
   9 # include <boost/detail/workaround.hpp>
  10 # include <boost/mpl/size.hpp>
  11 # include <memory>
  12
  13 namespace boost { namespace python { namespace objects {
  14
  15 // This type is used as a "generalized Python callback", wrapping the
  16 // function signature:
  17 //
  18 //      PyObject* (PyObject* args, PyObject* keywords)
  19
  20 struct BOOST_PYTHON_DECL py_function_impl_base
  21 {
  22     virtual ~py_function_impl_base();
  23     virtual PyObject* operator()(PyObject*, PyObject*) = 0;
  24     virtual unsigned min_arity() const = 0;
  25     virtual unsigned max_arity() const;
  26     virtual python::detail::py_func_sig_info signature() const = 0;
  27 };
  28
  29 template <class Caller>
  30 struct caller_py_function_impl : py_function_impl_base
  31 {
  32     caller_py_function_impl(Caller const& caller)
  33         : m_caller(caller)
  34     {}
  35
  36     PyObject* operator()(PyObject* args, PyObject* kw)
  37     {
  38         return m_caller(args, kw);
  39     }
  40
  41     virtual unsigned min_arity() const
  42     {
  43         return m_caller.min_arity();
  44     }
  45
  46     virtual python::detail::py_func_sig_info signature() const
  47     {
  48         return m_caller.signature();
  49     }
  50
  51  private:
  52     Caller m_caller;
  53 };
  54
  55 template <class Caller, class Sig>
  56 struct signature_py_function_impl : py_function_impl_base
  57 {
  58     signature_py_function_impl(Caller const& caller)
  59         : m_caller(caller)
  60     {}
  61
  62     PyObject* operator()(PyObject* args, PyObject* kw)
  63     {
  64         return m_caller(args, kw);
  65     }
  66
  67     virtual unsigned min_arity() const
  68     {
  69         return mpl::size<Sig>::value - 1;
  70     }
  71
  72     virtual python::detail::py_func_sig_info signature() const
  73     {
  74         python::detail::signature_element const* sig = python::detail::signature<Sig>::elements();
  75         python::detail::py_func_sig_info res = {sig, sig};
  76         return  res;
  77     }
  78
  79  private:
  80     Caller m_caller;
  81 };
  82
  83 template <class Caller, class Sig>
  84 struct full_py_function_impl : py_function_impl_base
  85 {
  86     full_py_function_impl(Caller const& caller, unsigned min_arity, unsigned max_arity)
  87       : m_caller(caller)
  88       , m_min_arity(min_arity)
  89       , m_max_arity(max_arity > min_arity ? max_arity : min_arity)
  90     {}
  91
  92     PyObject* operator()(PyObject* args, PyObject* kw)
  93     {
  94         return m_caller(args, kw);
  95     }
  96
  97     virtual unsigned min_arity() const
  98     {
  99         return m_min_arity;
 100     }
 101
 102     virtual unsigned max_arity() const
 103     {
 104         return m_max_arity;
 105     }
 106
 107     virtual python::detail::py_func_sig_info signature() const
 108     {
 109         python::detail::signature_element const* sig = python::detail::signature<Sig>::elements();
 110         python::detail::py_func_sig_info res = {sig, sig};
 111         return  res;
 112     }
 113
 114  private:
 115     Caller m_caller;
 116     unsigned m_min_arity;
 117     unsigned m_max_arity;
 118 };
 119
 120 struct py_function
 121 {
 122     template <class Caller>
 123     py_function(Caller const& caller)
 124         : m_impl(new caller_py_function_impl<Caller>(caller))
 125     {}
 126
 127     template <class Caller, class Sig>
 128     py_function(Caller const& caller, Sig)
 129       : m_impl(new signature_py_function_impl<Caller, Sig>(caller))
 130     {}
 131
 132     template <class Caller, class Sig>
 133     py_function(Caller const& caller, Sig, int min_arity, int max_arity = 0)
 134       : m_impl(new full_py_function_impl<Caller, Sig>(caller, min_arity, max_arity))
 135     {}
 136
 137     py_function(py_function const& rhs)
 138 #if defined(BOOST_NO_CXX11_SMART_PTR)
 139       : m_impl(rhs.m_impl)
 140 #else
 141       : m_impl(std::move(rhs.m_impl))
 142 #endif
 143     {}
 144
 145     PyObject* operator()(PyObject* args, PyObject* kw) const
 146     {
 147         return (*m_impl)(args, kw);
 148     }
 149
 150     unsigned min_arity() const
 151     {
 152         return m_impl->min_arity();
 153     }
 154
 155     unsigned max_arity() const
 156     {
 157         return m_impl->max_arity();
 158     }
 159
 160     python::detail::signature_element const* signature() const
 161     {
 162         return m_impl->signature().signature;
 163     }
 164
 165     python::detail::signature_element const& get_return_type() const
 166     {
 167         return *m_impl->signature().ret;
 168     }
 169
 170  private:
 171 #if defined(BOOST_NO_CXX11_SMART_PTR)
 172     mutable std::auto_ptr<py_function_impl_base> m_impl;
 173 #else
 174     mutable std::unique_ptr<py_function_impl_base> m_impl;
 175 #endif
 176 };
 177
 178 }}} // namespace boost::python::objects
 179
 180 #endif // PY_FUNCTION_DWA200286_HPP