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1 // Copyright David Abrahams 2001. |
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2 // Distributed under the Boost Software License, Version 1.0. (See |
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3 // accompanying file LICENSE_1_0.txt or copy at |
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4 // http://www.boost.org/LICENSE_1_0.txt) |
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5 #ifndef MAKE_CONSTRUCTOR_DWA20011221_HPP |
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6 # define MAKE_CONSTRUCTOR_DWA20011221_HPP |
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7 |
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8 # include <boost/python/detail/prefix.hpp> |
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9 |
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10 # include <boost/python/default_call_policies.hpp> |
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11 # include <boost/python/args.hpp> |
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12 # include <boost/python/object_fwd.hpp> |
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13 |
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14 # include <boost/python/object/function_object.hpp> |
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15 # include <boost/python/object/make_holder.hpp> |
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16 # include <boost/python/object/pointer_holder.hpp> |
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17 # include <boost/python/converter/context_result_converter.hpp> |
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18 |
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19 # include <boost/python/detail/caller.hpp> |
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20 # include <boost/python/detail/none.hpp> |
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21 |
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22 # include <boost/mpl/size.hpp> |
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23 # include <boost/mpl/int.hpp> |
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24 # include <boost/mpl/push_front.hpp> |
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25 # include <boost/mpl/pop_front.hpp> |
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26 |
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27 namespace boost { namespace python { |
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28 |
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29 namespace detail |
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30 { |
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31 template <class T> |
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32 struct install_holder : converter::context_result_converter |
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33 { |
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34 install_holder(PyObject* args_) |
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35 : m_self(PyTuple_GetItem(args_, 0)) {} |
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36 |
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37 PyObject* operator()(T x) const |
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38 { |
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39 dispatch(x, is_pointer<T>()); |
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40 return none(); |
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41 } |
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42 |
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43 private: |
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44 template <class U> |
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45 void dispatch(U* x, mpl::true_) const |
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46 { |
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47 std::auto_ptr<U> owner(x); |
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48 dispatch(owner, mpl::false_()); |
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49 } |
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50 |
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51 template <class Ptr> |
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52 void dispatch(Ptr x, mpl::false_) const |
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53 { |
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54 typedef typename pointee<Ptr>::type value_type; |
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55 typedef objects::pointer_holder<Ptr,value_type> holder; |
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56 typedef objects::instance<holder> instance_t; |
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57 |
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58 void* memory = holder::allocate(this->m_self, offsetof(instance_t, storage), sizeof(holder)); |
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59 try { |
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60 (new (memory) holder(x))->install(this->m_self); |
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61 } |
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62 catch(...) { |
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63 holder::deallocate(this->m_self, memory); |
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64 throw; |
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65 } |
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66 } |
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67 |
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68 PyObject* m_self; |
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69 }; |
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70 |
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71 struct constructor_result_converter |
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72 { |
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73 template <class T> |
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74 struct apply |
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75 { |
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76 typedef install_holder<T> type; |
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77 }; |
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78 }; |
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79 |
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80 template <class BaseArgs, class Offset> |
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81 struct offset_args |
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82 { |
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83 offset_args(BaseArgs base_) : base(base_) {} |
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84 BaseArgs base; |
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85 }; |
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86 |
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87 template <int N, class BaseArgs, class Offset> |
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88 inline PyObject* get(mpl::int_<N>, offset_args<BaseArgs,Offset> const& args_) |
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89 { |
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90 return get(mpl::int_<(N+Offset::value)>(), args_.base); |
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91 } |
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92 |
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93 template <class BaseArgs, class Offset> |
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94 inline unsigned arity(offset_args<BaseArgs,Offset> const& args_) |
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95 { |
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96 return arity(args_.base) - Offset::value; |
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97 } |
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98 |
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99 template <class BasePolicy_ = default_call_policies> |
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100 struct constructor_policy : BasePolicy_ |
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101 { |
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102 constructor_policy(BasePolicy_ base) : BasePolicy_(base) {} |
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103 |
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104 // If the BasePolicy_ supplied a result converter it would be |
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105 // ignored; issue an error if it's not the default. |
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106 BOOST_STATIC_ASSERT(( |
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107 is_same< |
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108 typename BasePolicy_::result_converter |
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109 , default_result_converter |
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110 >::value |
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111 )); |
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112 |
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113 typedef constructor_result_converter result_converter; |
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114 typedef offset_args<typename BasePolicy_::argument_package, mpl::int_<1> > argument_package; |
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115 }; |
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116 |
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117 template <class InnerSignature> |
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118 struct outer_constructor_signature |
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119 { |
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120 typedef typename mpl::pop_front<InnerSignature>::type inner_args; |
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121 typedef typename mpl::push_front<inner_args,object>::type outer_args; |
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122 typedef typename mpl::push_front<outer_args,void>::type type; |
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123 }; |
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124 |
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125 // ETI workaround |
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126 template <> |
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127 struct outer_constructor_signature<int> |
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128 { |
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129 typedef int type; |
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130 }; |
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131 |
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132 // |
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133 // These helper functions for make_constructor (below) do the raw work |
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134 // of constructing a Python object from some invokable entity. See |
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135 // <boost/python/detail/caller.hpp> for more information about how |
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136 // the Sig arguments is used. |
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137 // |
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138 // @group make_constructor_aux { |
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139 template <class F, class CallPolicies, class Sig> |
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140 object make_constructor_aux( |
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141 F f // An object that can be invoked by detail::invoke() |
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142 , CallPolicies const& p // CallPolicies to use in the invocation |
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143 , Sig const& // An MPL sequence of argument types expected by F |
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144 ) |
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145 { |
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146 typedef typename outer_constructor_signature<Sig>::type outer_signature; |
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147 |
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148 typedef constructor_policy<CallPolicies> inner_policy; |
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149 |
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150 return objects::function_object( |
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151 objects::py_function( |
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152 detail::caller<F,inner_policy,Sig>(f, inner_policy(p)) |
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153 , outer_signature() |
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154 ) |
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155 ); |
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156 } |
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157 |
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158 // As above, except that it accepts argument keywords. NumKeywords |
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159 // is used only for a compile-time assertion to make sure the user |
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160 // doesn't pass more keywords than the function can accept. To |
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161 // disable all checking, pass mpl::int_<0> for NumKeywords. |
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162 template <class F, class CallPolicies, class Sig, class NumKeywords> |
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163 object make_constructor_aux( |
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164 F f |
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165 , CallPolicies const& p |
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166 , Sig const& |
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167 , detail::keyword_range const& kw // a [begin,end) pair of iterators over keyword names |
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168 , NumKeywords // An MPL integral type wrapper: the size of kw |
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169 ) |
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170 { |
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171 enum { arity = mpl::size<Sig>::value - 1 }; |
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172 |
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173 typedef typename detail::error::more_keywords_than_function_arguments< |
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174 NumKeywords::value, arity |
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175 >::too_many_keywords assertion; |
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176 |
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177 typedef typename outer_constructor_signature<Sig>::type outer_signature; |
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178 |
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179 typedef constructor_policy<CallPolicies> inner_policy; |
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180 |
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181 return objects::function_object( |
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182 objects::py_function( |
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183 detail::caller<F,inner_policy,Sig>(f, inner_policy(p)) |
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184 , outer_signature() |
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185 ) |
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186 , kw |
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187 ); |
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188 } |
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189 // } |
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190 |
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191 // |
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192 // These dispatch functions are used to discriminate between the |
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193 // cases when the 3rd argument is keywords or when it is a |
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194 // signature. |
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195 // |
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196 // @group Helpers for make_constructor when called with 3 arguments. { |
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197 // |
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198 template <class F, class CallPolicies, class Keywords> |
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199 object make_constructor_dispatch(F f, CallPolicies const& policies, Keywords const& kw, mpl::true_) |
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200 { |
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201 return detail::make_constructor_aux( |
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202 f |
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203 , policies |
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204 , detail::get_signature(f) |
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205 , kw.range() |
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206 , mpl::int_<Keywords::size>() |
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207 ); |
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208 } |
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209 |
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210 template <class F, class CallPolicies, class Signature> |
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211 object make_constructor_dispatch(F f, CallPolicies const& policies, Signature const& sig, mpl::false_) |
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212 { |
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213 return detail::make_constructor_aux( |
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214 f |
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215 , policies |
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216 , sig |
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217 ); |
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218 } |
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219 // } |
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220 } |
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221 |
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222 // These overloaded functions wrap a function or member function |
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223 // pointer as a Python object, using optional CallPolicies, |
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224 // Keywords, and/or Signature. @group { |
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225 // |
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226 template <class F> |
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227 object make_constructor(F f) |
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228 { |
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229 return detail::make_constructor_aux( |
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230 f,default_call_policies(), detail::get_signature(f)); |
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231 } |
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232 |
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233 template <class F, class CallPolicies> |
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234 object make_constructor(F f, CallPolicies const& policies) |
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235 { |
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236 return detail::make_constructor_aux( |
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237 f, policies, detail::get_signature(f)); |
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238 } |
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239 |
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240 template <class F, class CallPolicies, class KeywordsOrSignature> |
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241 object make_constructor( |
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242 F f |
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243 , CallPolicies const& policies |
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244 , KeywordsOrSignature const& keywords_or_signature) |
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245 { |
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246 typedef typename |
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247 detail::is_reference_to_keywords<KeywordsOrSignature&>::type |
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248 is_kw; |
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249 |
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250 return detail::make_constructor_dispatch( |
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251 f |
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252 , policies |
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253 , keywords_or_signature |
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254 , is_kw() |
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255 ); |
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256 } |
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257 |
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258 template <class F, class CallPolicies, class Keywords, class Signature> |
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259 object make_constructor( |
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260 F f |
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261 , CallPolicies const& policies |
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262 , Keywords const& kw |
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263 , Signature const& sig |
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264 ) |
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265 { |
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266 return detail::make_constructor_aux( |
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267 f |
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268 , policies |
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269 , sig |
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270 , kw.range() |
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271 , mpl::int_<Keywords::size>() |
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272 ); |
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273 } |
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274 // } |
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275 |
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276 }} |
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277 |
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278 |
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279 #endif // MAKE_CONSTRUCTOR_DWA20011221_HPP |