1  /* Common code for use by all hashlib related modules. */
       2  
       3  /*
       4   * Given a PyObject* obj, fill in the Py_buffer* viewp with the result
       5   * of PyObject_GetBuffer.  Sets an exception and issues the erraction
       6   * on any errors, e.g. 'return NULL' or 'goto error'.
       7   */
       8  #define GET_BUFFER_VIEW_OR_ERROR(obj, viewp, erraction) do { \
       9          if (PyUnicode_Check((obj))) { \
      10              PyErr_SetString(PyExc_TypeError, \
      11                              "Strings must be encoded before hashing");\
      12              erraction; \
      13          } \
      14          if (!PyObject_CheckBuffer((obj))) { \
      15              PyErr_SetString(PyExc_TypeError, \
      16                              "object supporting the buffer API required"); \
      17              erraction; \
      18          } \
      19          if (PyObject_GetBuffer((obj), (viewp), PyBUF_SIMPLE) == -1) { \
      20              erraction; \
      21          } \
      22          if ((viewp)->ndim > 1) { \
      23              PyErr_SetString(PyExc_BufferError, \
      24                              "Buffer must be single dimension"); \
      25              PyBuffer_Release((viewp)); \
      26              erraction; \
      27          } \
      28      } while(0)
      29  
      30  #define GET_BUFFER_VIEW_OR_ERROUT(obj, viewp) \
      31      GET_BUFFER_VIEW_OR_ERROR(obj, viewp, return NULL)
      32  
      33  /*
      34   * Helper code to synchronize access to the hash object when the GIL is
      35   * released around a CPU consuming hashlib operation. All code paths that
      36   * access a mutable part of obj must be enclosed in an ENTER_HASHLIB /
      37   * LEAVE_HASHLIB block or explicitly acquire and release the lock inside
      38   * a PY_BEGIN / END_ALLOW_THREADS block if they wish to release the GIL for
      39   * an operation.
      40   *
      41   * These only drop the GIL if the lock acquisition itself is likely to
      42   * block. Thus the non-blocking acquire gating the GIL release for a
      43   * blocking lock acquisition. The intent of these macros is to surround
      44   * the assumed always "fast" operations that you aren't releasing the
      45   * GIL around.  Otherwise use code similar to what you see in hash
      46   * function update() methods.
      47   */
      48  
      49  #include "pythread.h"
      50  #define ENTER_HASHLIB(obj) \
      51      if ((obj)->lock) { \
      52          if (!PyThread_acquire_lock((obj)->lock, 0)) { \
      53              Py_BEGIN_ALLOW_THREADS \
      54              PyThread_acquire_lock((obj)->lock, 1); \
      55              Py_END_ALLOW_THREADS \
      56          } \
      57      }
      58  #define LEAVE_HASHLIB(obj) \
      59      if ((obj)->lock) { \
      60          PyThread_release_lock((obj)->lock); \
      61      }
      62  
      63  /* TODO(gpshead): We should make this a module or class attribute
      64   * to allow the user to optimize based on the platform they're using. */
      65  #define HASHLIB_GIL_MINSIZE 2048
      66