lib/util/talloc_stack.h

   1 /*
   2    Unix SMB/CIFS implementation.
   3    Implement a stack of talloc contexts
   4    Copyright (C) Volker Lendecke 2007
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 2 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; if not, write to the Free Software
  18    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19 */
  20
  21 /*
  22  * Implement a stack of talloc frames.
  23  *
  24  * When a new talloc stackframe is allocated with talloc_stackframe(), then
  25  * the TALLOC_CTX returned with talloc_tos() is reset to that new
  26  * frame. Whenever that stack frame is TALLOC_FREE()'ed, then the reverse
  27  * happens: The previous talloc_tos() is restored.
  28  *
  29  * This API is designed to be robust in the sense that if someone forgets to
  30  * TALLOC_FREE() a stackframe, then the next outer one correctly cleans up and
  31  * resets the talloc_tos().
  32  *
  33  */
  34
  35 #ifndef _TALLOC_STACK_H
  36 #define _TALLOC_STACK_H
  37
  38 #include <talloc.h>
  39
  40 /*
  41  * Create a new talloc stack frame.
  42  *
  43  * When free'd, it frees all stack frames that were created after this one and
  44  * not explicitly freed.
  45  */
  46
  47 #define talloc_stackframe() _talloc_stackframe(__location__)
  48 #define talloc_stackframe_pool(sz) _talloc_stackframe_pool(__location__, (sz))
  49 TALLOC_CTX *_talloc_stackframe(const char *location);
  50 TALLOC_CTX *_talloc_stackframe_pool(const char *location, size_t poolsize);
  51
  52 /*
  53  * Get us the current top of the talloc stack.
  54  */
  55
  56 #define talloc_tos() _talloc_tos(__location__)
  57 TALLOC_CTX *_talloc_tos(const char *location);
  58
  59 /*
  60  * return true if a talloc stackframe exists
  61  * this can be used to prevent memory leaks for code that can
  62  * optionally use a talloc stackframe (eg. nt_errstr())
  63  */
  64
  65 bool talloc_stackframe_exists(void);
  66
  67 #endif