Backported PyCapsule from 3.1, and converted most uses of
CObject to PyCapsule.
diff --git a/Include/pycapsule.h b/Include/pycapsule.h
new file mode 100644
index 0000000..2cc1c73
--- /dev/null
+++ b/Include/pycapsule.h
@@ -0,0 +1,148 @@
+
+/* Capsule objects let you wrap a C "void *" pointer in a Python
+ object. They're a way of passing data through the Python interpreter
+ without creating your own custom type.
+
+ Capsules are used for communication between extension modules.
+ They provide a way for an extension module to export a C interface
+ to other extension modules, so that extension modules can use the
+ Python import mechanism to link to one another.
+
+ For more information, please see "c-api/capsule.html" in the
+ documentation.
+*/
+
+#ifndef Py_CAPSULE_H
+#define Py_CAPSULE_H
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+PyAPI_DATA(PyTypeObject) PyCapsule_Type;
+
+typedef void (*PyCapsule_Destructor)(PyObject *);
+
+#define PyCapsule_CheckExact(op) (Py_TYPE(op) == &PyCapsule_Type)
+
+
+PyAPI_FUNC(PyObject *) PyCapsule_New(
+ void *pointer,
+ const char *name,
+ PyCapsule_Destructor destructor);
+
+PyAPI_FUNC(void *) PyCapsule_GetPointer(PyObject *capsule, const char *name);
+
+PyAPI_FUNC(PyCapsule_Destructor) PyCapsule_GetDestructor(PyObject *capsule);
+
+PyAPI_FUNC(const char *) PyCapsule_GetName(PyObject *capsule);
+
+PyAPI_FUNC(void *) PyCapsule_GetContext(PyObject *capsule);
+
+PyAPI_FUNC(int) PyCapsule_IsValid(PyObject *capsule, const char *name);
+
+PyAPI_FUNC(int) PyCapsule_SetPointer(PyObject *capsule, void *pointer);
+
+PyAPI_FUNC(int) PyCapsule_SetDestructor(PyObject *capsule, PyCapsule_Destructor destructor);
+
+PyAPI_FUNC(int) PyCapsule_SetName(PyObject *capsule, const char *name);
+
+PyAPI_FUNC(int) PyCapsule_SetContext(PyObject *capsule, void *context);
+
+PyAPI_FUNC(void *) PyCapsule_Import(const char *name, int no_block);
+
+
+#define PYTHON_USING_CAPSULE
+
+#define PYCAPSULE_INSTANTIATE_DESTRUCTOR(name, destructor) \
+static void pycapsule_destructor_ ## name(PyObject *ptr) \
+{ \
+ void *p = PyCapsule_GetPointer(ptr, name); \
+ if (p) { \
+ destructor(p); \
+ } \
+} \
+
+#define PYCAPSULE_NEW(pointer, name) \
+ (PyCapsule_New(pointer, name, capsule_destructor_ ## name))
+
+#define PYCAPSULE_ISVALID(capsule, name) \
+ (PyCapsule_IsValid(capsule, name))
+
+#define PYCAPSULE_DEREFERENCE(capsule, name) \
+ (PyCapsule_GetPointer(capsule, name))
+
+#define PYCAPSULE_SET(capsule, name, value) \
+ (PyCapsule_IsValid(capsule, name) && PyCapsule_SetPointer(capsule, value))
+
+/* module and attribute should be specified as string constants */
+#define PYCAPSULE_IMPORT(module, attribute) \
+ (PyCapsule_Import(module "." attribute, 0))
+
+
+/* begin public-domain code */
+/*
+** This code was written by Larry Hastings,
+** and is dedicated to the public domain.
+** It's designed to make it easy to switch
+** from CObject to Capsule objects without losing
+** backwards compatibility with prior versions
+** of CPython. You're encouraged to copy this code
+** (including this documentation) into your
+** Python C extension.
+**
+** To use:
+** * #define a name for the pointer you store in
+** the CObject. If you make the CObject available
+** as part of your module's API, this name should
+** be "modulename.attributename", and it should be
+** considered part of your API (so put it in your
+** header file).
+** * Specify a PYCAPSULE_INSTANTIATE_DESTRUCTOR(), in
+** every C file that creates these CObjects. This
+** is where you specify your object's destructor.
+** * Change all calls to CObject_FromVoidPtr()
+** and CObject_FromVoidPointerAndDesc() into
+** PYCAPSULE_NEW() calls.
+** * Change all calls to PyCObject_AsVoidPtr()
+** into PYCAPSULE_DEREFERENCE() calls.
+** * Change all calls to PyCObject_SetVoidPtr()
+** into PYCAPSULE_SET() calls.
+** * Change all calls to PyCObject_Import()
+** into PYCAPSULE_IMPORT() calls. Note that
+** the two arguments to PYCAPSULE_IMPORT()
+** should both be string constants; that is,
+** you should call
+** PYCAPSULE_IMPORT("modulename", "attributename"),
+** not PYCAPSULE_IMPORT(charstar1, charstar2).
+*/
+#ifndef PYTHON_USING_CAPSULE
+
+#define PYCAPSULE_INSTANTIATE_DESTRUCTOR(name, destructor) \
+static void pycapsule_destructor_ ## name(void *ptr) \
+{ \
+ destructor(p); \
+} \
+
+#define PYCAPSULE_NEW(pointer, name) \
+ (PyCObject_FromVoidPtr(pointer, pycapsule_destructor_ ## name))
+
+#define PYCAPSULE_ISVALID(capsule, name) \
+ (PyCObject_Check(capsule))
+
+#define PYCAPSULE_DEREFERENCE(capsule, name) \
+ (PyCObject_AsVoidPtr(capsule))
+
+#define PYCAPSULE_SET(capsule, name, value) \
+ (PyCObject_SetVoidPtr(capsule, value))
+
+/* module and attribute should be specified as string constants */
+#define PYCAPSULE_IMPORT(module, attribute) \
+ (PyCObject_Import(module, attribute))
+
+#endif /* PYTHON_USING_CAPSULE */
+/* end public-domain code */
+
+#ifdef __cplusplus
+}
+#endif
+#endif /* !Py_CAPSULE_H */