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#ifndef WREPORT_PYTHON_CORE_H
#define WREPORT_PYTHON_CORE_H
#define PY_SSIZE_T_CLEAN
#include <Python.h>
#include <stdexcept>
namespace wreport {
namespace python {
/**
* unique_ptr-like object that contains PyObject pointers, and that calls
* Py_DECREF on destruction.
*/
template<typename Obj>
class py_unique_ptr
{
protected:
Obj* ptr;
public:
py_unique_ptr() : ptr(nullptr) {}
py_unique_ptr(Obj* o) : ptr(o) {}
py_unique_ptr(const py_unique_ptr&) = delete;
py_unique_ptr(py_unique_ptr&& o) : ptr(o.ptr) { o.ptr = nullptr; }
~py_unique_ptr() { Py_XDECREF(ptr); }
py_unique_ptr& operator=(const py_unique_ptr&) = delete;
py_unique_ptr& operator=(py_unique_ptr&& o)
{
if (this == &o) return *this;
Py_XDECREF(ptr);
ptr = o.ptr;
o.ptr = nullptr;
return *this;
}
void incref() { Py_XINCREF(ptr); }
void decref() { Py_XDECREF(ptr); }
void clear()
{
Py_XDECREF(ptr);
ptr = nullptr;
}
void reset(Obj* o)
{
Py_XDECREF(ptr);
ptr = o;
}
/// Release the reference without calling Py_DECREF
Obj* release()
{
Obj* res = ptr;
ptr = nullptr;
return res;
}
/// Call repr() on the object
std::string repr()
{
if (!ptr)
return "(null)";
py_unique_ptr<PyObject> py_repr(PyObject_Repr(ptr));
if (!py_repr)
{
PyErr_Clear();
return "(repr failed)";
}
Py_ssize_t size;
const char* res = PyUnicode_AsUTF8AndSize(py_repr, &size);
return std::string(res, size);
}
/// Call str() on the object
std::string str()
{
if (!ptr)
return "(null)";
py_unique_ptr<PyObject> py_repr(PyObject_Str(ptr));
if (!py_repr)
{
PyErr_Clear();
return "(str failed)";
}
Py_ssize_t size;
const char* res = PyUnicode_AsUTF8AndSize(py_repr, &size);
return std::string(res, size);
}
/// Use it as a Obj
operator Obj*() { return ptr; }
/// Use it as a Obj
operator Obj*() const { return ptr; }
/// Use it as a Obj
Obj* operator->() { return ptr; }
/// Use it as a Obj
Obj* operator->() const { return ptr; }
/// Get the pointer (useful for passing to Py_BuildValue)
Obj* get() { return ptr; }
/// Get the pointer (useful for passing to Py_BuildValue)
Obj* get() const { return ptr; }
};
typedef py_unique_ptr<PyObject> pyo_unique_ptr;
/**
* Release the GIL during the lifetime of this object;
*/
class ReleaseGIL
{
PyThreadState *_save = nullptr;
public:
ReleaseGIL()
{
_save = PyEval_SaveThread();
}
~ReleaseGIL()
{
lock();
}
void lock()
{
if (!_save) return;
PyEval_RestoreThread(_save);
_save = nullptr;
}
};
/**
* Acquire the GIL prior to invoking python code.
*
* This also works correctly if the GIL is already acquired, so it can be used
* to wrap invocation of python code regardless of the GIL status.
*/
class AcquireGIL
{
PyGILState_STATE _state;
public:
AcquireGIL()
{
_state = PyGILState_Ensure();
}
~AcquireGIL()
{
PyGILState_Release(_state);
}
};
/**
* Exception raised when a python function returns an error with an exception
* set.
*
* When catching this exception, python exception information is already set,
* so the only thing to do is to return the appropriate error to the python
* caller.
*
* This exception carries to information, because it is all set in the python
* exception information.
*/
struct PythonException : public std::exception {};
/**
* Throw PythonException if the given pointer is nullptr.
*
* This can be used to wrap Python API invocations, throwing PythonException if
* the API call returned an error.
*/
template<typename T>
inline T* throw_ifnull(T* o)
{
if (!o) throw PythonException();
return o;
}
}
}
#endif
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