pythonnet/src/runtime/constructorbinding.cs at master · anamariamocanu/pythonnet · GitHub

Repository navigation

History

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

122

123

124

125

126

127

128

129

130

131

132

133

134

135

136

137

138

139

140

141

142

143

144

145

146

147

148

149

150

151

152

153

154

155

156

157

158

159

160

161

162

163

164

165

166

167

168

169

170

171

172

173

174

175

176

177

178

179

180

181

182

183

184

185

186

187

188

189

190

191

192

193

194

195

196

197

198

199

200

201

202

203

204

205

206

207

208

209

210

211

212

213

214

215

216

217

218

219

220

221

222

223

224

225

226

227

228

229

230

231

232

233

234

235

236

237

using System;

using System.Reflection;

namespace Python.Runtime

{

/// <summary>

/// Implements a Python type that wraps a CLR ctor call. Constructor objects

/// support a .Overloads[] syntax to allow explicit ctor overload selection.

/// </summary>

/// <remarks>

/// ClassManager stores a ConstructorBinding instance in the class's __dict__['Overloads']

/// SomeType.Overloads[Type, ...] works like this:

/// 1) Python retrieves the Overloads attribute from this ClassObject's dictionary normally

/// and finds a non-null tp_descr_get slot which is called by the interpreter

/// and returns an IncRef()ed pyHandle to itself.

/// 2) The ConstructorBinding object handles the [] syntax in its mp_subscript by matching

/// the Type object parameters to a constructor overload using Type.GetConstructor()

/// [NOTE: I don't know why method overloads are not searched the same way.]

/// and creating the BoundContructor object which contains ContructorInfo object.

/// 3) In tp_call, if ctorInfo is not null, ctorBinder.InvokeRaw() is called.

/// </remarks>

internal class ConstructorBinding : ExtensionType

{

private Type type; // The managed Type being wrapped in a ClassObject

private IntPtr pyTypeHndl; // The python type tells GetInstHandle which Type to create.

private ConstructorBinder ctorBinder;

private IntPtr repr;

public ConstructorBinding(Type type, IntPtr pyTypeHndl, ConstructorBinder ctorBinder)

{

this.type = type;

Runtime.XIncref(pyTypeHndl);

this.pyTypeHndl = pyTypeHndl;

this.ctorBinder = ctorBinder;

repr = IntPtr.Zero;

}

/// <summary>

/// Descriptor __get__ implementation.

/// Implements a Python type that wraps a CLR ctor call that requires the use

/// of a .Overloads[pyTypeOrType...] syntax to allow explicit ctor overload

/// selection.

/// </summary>

/// <param name="op"> PyObject* to a Constructors wrapper </param>

/// <param name="instance">

/// the instance that the attribute was accessed through,

/// or None when the attribute is accessed through the owner

/// </param>

/// <param name="owner"> always the owner class </param>

/// <returns>

/// a CtorMapper (that borrows a reference to this python type and the

/// ClassObject's ConstructorBinder) wrapper.

/// </returns>

/// <remarks>

/// Python 2.6.5 docs:

/// object.__get__(self, instance, owner)

/// Called to get the attribute of the owner class (class attribute access)

/// or of an instance of that class (instance attribute access).

/// owner is always the owner class, while instance is the instance that

/// the attribute was accessed through, or None when the attribute is accessed through the owner.

/// This method should return the (computed) attribute value or raise an AttributeError exception.

/// </remarks>

public static IntPtr tp_descr_get(IntPtr op, IntPtr instance, IntPtr owner)

{

var self = (ConstructorBinding)GetManagedObject(op);

if (self == null)

{

return IntPtr.Zero;

}

// It doesn't seem to matter if it's accessed through an instance (rather than via the type).

/*if (instance != IntPtr.Zero) {

// This is ugly! PyObject_IsInstance() returns 1 for true, 0 for false, -1 for error...

if (Runtime.PyObject_IsInstance(instance, owner) < 1) {

return Exceptions.RaiseTypeError("How in the world could that happen!");

}

}*/

Runtime.XIncref(self.pyHandle);

return self.pyHandle;

}

/// <summary>

/// Implement explicit overload selection using subscript syntax ([]).

/// </summary>

/// <remarks>

/// ConstructorBinding.GetItem(PyObject *o, PyObject *key)

/// Return element of o corresponding to the object key or NULL on failure.

/// This is the equivalent of the Python expression o[key].

/// </remarks>

public static IntPtr mp_subscript(IntPtr op, IntPtr key)

{

var self = (ConstructorBinding)GetManagedObject(op);

Type[] types = Runtime.PythonArgsToTypeArray(key);

if (types == null)

{

return Exceptions.RaiseTypeError("type(s) expected");

}

//MethodBase[] methBaseArray = self.ctorBinder.GetMethods();

//MethodBase ci = MatchSignature(methBaseArray, types);

ConstructorInfo ci = self.type.GetConstructor(types);

if (ci == null)

{

return Exceptions.RaiseTypeError("No match found for constructor signature");

}

var boundCtor = new BoundContructor(self.type, self.pyTypeHndl, self.ctorBinder, ci);

return boundCtor.pyHandle;

}

/// <summary>

/// ConstructorBinding __repr__ implementation [borrowed from MethodObject].

/// </summary>

public static IntPtr tp_repr(IntPtr ob)

{

var self = (ConstructorBinding)GetManagedObject(ob);

if (self.repr != IntPtr.Zero)

{

Runtime.XIncref(self.repr);

return self.repr;

}

MethodBase[] methods = self.ctorBinder.GetMethods();

string name = self.type.FullName;

var doc = "";

foreach (MethodBase t in methods)

{

if (doc.Length > 0)

{

doc += "\n";

}

string str = t.ToString();

int idx = str.IndexOf("(");

doc += string.Format("{0}{1}", name, str.Substring(idx));

}

self.repr = Runtime.PyString_FromString(doc);

Runtime.XIncref(self.repr);

return self.repr;

}

/// <summary>

/// ConstructorBinding dealloc implementation.

/// </summary>

public new static void tp_dealloc(IntPtr ob)

{

var self = (ConstructorBinding)GetManagedObject(ob);

Runtime.XDecref(self.repr);

Runtime.XDecref(self.pyTypeHndl);

ExtensionType.FinalizeObject(self);

}

/// <summary>

/// Implements a Python type that constructs the given Type given a particular ContructorInfo.

/// </summary>

/// <remarks>

/// Here mostly because I wanted a new __repr__ function for the selected constructor.

/// An earlier implementation hung the __call__ on the ContructorBinding class and

/// returned an Incref()ed self.pyHandle from the __get__ function.

/// </remarks>

internal class BoundContructor : ExtensionType

{

private Type type; // The managed Type being wrapped in a ClassObject

private IntPtr pyTypeHndl; // The python type tells GetInstHandle which Type to create.

private ConstructorBinder ctorBinder;

private ConstructorInfo ctorInfo;

private IntPtr repr;

public BoundContructor(Type type, IntPtr pyTypeHndl, ConstructorBinder ctorBinder, ConstructorInfo ci)

{

this.type = type;

Runtime.XIncref(pyTypeHndl);

this.pyTypeHndl = pyTypeHndl;

this.ctorBinder = ctorBinder;

ctorInfo = ci;

repr = IntPtr.Zero;

}

/// <summary>

/// BoundContructor.__call__(PyObject *callable_object, PyObject *args, PyObject *kw)

/// </summary>

/// <param name="op"> PyObject *callable_object </param>

/// <param name="args"> PyObject *args </param>

/// <param name="kw"> PyObject *kw </param>

/// <returns> A reference to a new instance of the class by invoking the selected ctor(). </returns>

public static IntPtr tp_call(IntPtr op, IntPtr args, IntPtr kw)

{

var self = (BoundContructor)GetManagedObject(op);

// Even though a call with null ctorInfo just produces the old behavior

/*if (self.ctorInfo == null) {

string msg = "Usage: Class.Overloads[CLR_or_python_Type, ...]";

return Exceptions.RaiseTypeError(msg);

}*/

// Bind using ConstructorBinder.Bind and invoke the ctor providing a null instancePtr

// which will fire self.ctorInfo using ConstructorInfo.Invoke().

object obj = self.ctorBinder.InvokeRaw(IntPtr.Zero, args, kw, self.ctorInfo);

if (obj == null)

{

// XXX set an error

return IntPtr.Zero;

}

// Instantiate the python object that wraps the result of the method call

// and return the PyObject* to it.

return CLRObject.GetInstHandle(obj, self.pyTypeHndl);

}

/// <summary>

/// BoundContructor __repr__ implementation [borrowed from MethodObject].

/// </summary>

public static IntPtr tp_repr(IntPtr ob)

{

var self = (BoundContructor)GetManagedObject(ob);

if (self.repr != IntPtr.Zero)

{

Runtime.XIncref(self.repr);

return self.repr;

}

string name = self.type.FullName;

string str = self.ctorInfo.ToString();

int idx = str.IndexOf("(");

str = string.Format("returns a new {0}{1}", name, str.Substring(idx));

self.repr = Runtime.PyString_FromString(str);

Runtime.XIncref(self.repr);

return self.repr;

}

/// <summary>

/// ConstructorBinding dealloc implementation.

/// </summary>

public new static void tp_dealloc(IntPtr ob)

{

var self = (BoundContructor)GetManagedObject(ob);

Runtime.XDecref(self.repr);

Runtime.XDecref(self.pyTypeHndl);

FinalizeObject(self);

}

pythonnet/src/runtime/constructorbinding.cs at master · anamariamocanu/pythonnet · GitHub

Repository navigation

Expand file tree

Breadcrumbs

constructorbinding.cs

Latest commit

History

Breadcrumbs

constructorbinding.cs

File metadata and controls