/* Common code for use by all hashlib related modules. */

/*
 * Given a PyObject* obj, fill in the Py_buffer* viewp with the result
 * of PyObject_GetBuffer. Sets an exception and issues the erraction
 * on any errors, e.g. 'return NULL' or 'goto error'.
 */
#define GET_BUFFER_VIEW_OR_ERROR(obj, viewp, erraction) do { \
 if (PyUnicode_Check((obj))) { \
 PyErr_SetString(PyExc_TypeError, \
 "Unicode-objects must be encoded before hashing");\
 erraction; \
 } \
 if (!PyObject_CheckBuffer((obj))) { \
 PyErr_SetString(PyExc_TypeError, \
 "object supporting the buffer API required"); \
 erraction; \
 } \
 if (PyObject_GetBuffer((obj), (viewp), PyBUF_SIMPLE) == -1) { \
 erraction; \
 } \
 if ((viewp)->ndim > 1) { \
 PyErr_SetString(PyExc_BufferError, \
 "Buffer must be single dimension"); \
 PyBuffer_Release((viewp)); \
 erraction; \
 } \
 } while(0)

#define GET_BUFFER_VIEW_OR_ERROUT(obj, viewp) \
 GET_BUFFER_VIEW_OR_ERROR(obj, viewp, return NULL)

/*
 * Helper code to synchronize access to the hash object when the GIL is
 * released around a CPU consuming hashlib operation. All code paths that
 * access a mutable part of obj must be enclosed in an ENTER_HASHLIB /
 * LEAVE_HASHLIB block or explicitly acquire and release the lock inside
 * a PY_BEGIN / END_ALLOW_THREADS block if they wish to release the GIL for
 * an operation.
 */

#include "pythread.h"
#define ENTER_HASHLIB(obj) \
 if ((obj)->lock) { \
 if (!PyThread_acquire_lock((obj)->lock, 0)) { \
 Py_BEGIN_ALLOW_THREADS \
 PyThread_acquire_lock((obj)->lock, 1); \
 Py_END_ALLOW_THREADS \
 } \
 }
#define LEAVE_HASHLIB(obj) \
 if ((obj)->lock) { \
 PyThread_release_lock((obj)->lock); \
 }

/* TODO(gps): We should probably make this a module or EVPobject attribute
 * to allow the user to optimize based on the platform they're using. */
#define HASHLIB_GIL_MINSIZE 2048