cpython/Modules/hashlib.h

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

#include "pycore_lock.h"        // PyMutex

/*
 * 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) …

#define GET_BUFFER_VIEW_OR_ERROUT(obj, viewp) …

/*
 * 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.
 *
 * These only drop the GIL if the lock acquisition itself is likely to
 * block. Thus the non-blocking acquire gating the GIL release for a
 * blocking lock acquisition. The intent of these macros is to surround
 * the assumed always "fast" operations that you aren't releasing the
 * GIL around.  Otherwise use code similar to what you see in hash
 * function update() methods.
 */

#include "pythread.h"
#define ENTER_HASHLIB(obj) …
#define LEAVE_HASHLIB(obj) …

#ifdef Py_GIL_DISABLED
#define HASHLIB_INIT_MUTEX …
#else
#define HASHLIB_INIT_MUTEX(obj) …
#endif

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