gdb/continuations.c

   1 /* Continuations for GDB, the GNU debugger.
   2
   3    Copyright (C) 1986-2020 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 #include "defs.h"
  21 #include "gdbthread.h"
  22 #include "inferior.h"
  23 #include "continuations.h"
  24
  25 struct continuation
  26 {
  27   struct continuation *next;
  28   continuation_ftype *function;
  29   continuation_free_arg_ftype *free_arg;
  30   void *arg;
  31 };
  32
  33 /* Add a new continuation to the continuation chain.  Args are
  34    FUNCTION to run the continuation up with, and ARG to pass to
  35    it.  */
  36
  37 static void
  38 make_continuation (struct continuation **pmy_chain,
  39                    continuation_ftype *function,
  40                    void *arg,  void (*free_arg) (void *))
  41 {
  42   struct continuation *newobj = XNEW (struct continuation);
  43
  44   newobj->next = *pmy_chain;
  45   newobj->function = function;
  46   newobj->free_arg = free_arg;
  47   newobj->arg = arg;
  48   *pmy_chain = newobj;
  49 }
  50
  51 static void
  52 do_my_continuations_1 (struct continuation **pmy_chain, int err)
  53 {
  54   struct continuation *ptr;
  55
  56   while ((ptr = *pmy_chain) != NULL)
  57     {
  58       *pmy_chain = ptr->next;   /* Do this first in case of recursion.  */
  59       (*ptr->function) (ptr->arg, err);
  60       if (ptr->free_arg)
  61         (*ptr->free_arg) (ptr->arg);
  62       xfree (ptr);
  63     }
  64 }
  65
  66 static void
  67 do_my_continuations (struct continuation **list, int err)
  68 {
  69   struct continuation *continuations;
  70
  71   if (*list == NULL)
  72     return;
  73
  74   /* Copy the list header into another pointer, and set the global
  75      list header to null, so that the global list can change as a side
  76      effect of invoking the continuations and the processing of the
  77      preexisting continuations will not be affected.  */
  78
  79   continuations = *list;
  80   *list = NULL;
  81
  82   /* Work now on the list we have set aside.  */
  83   do_my_continuations_1 (&continuations, err);
  84 }
  85
  86 static void
  87 discard_my_continuations_1 (struct continuation **pmy_chain)
  88 {
  89   struct continuation *ptr;
  90
  91   while ((ptr = *pmy_chain) != NULL)
  92     {
  93       *pmy_chain = ptr->next;
  94       if (ptr->free_arg)
  95         (*ptr->free_arg) (ptr->arg);
  96       xfree (ptr);
  97     }
  98 }
  99
 100 static void
 101 discard_my_continuations (struct continuation **list)
 102 {
 103   discard_my_continuations_1 (list);
 104   *list = NULL;
 105 }
 106
 107 /* Add a continuation to the continuation list of INFERIOR.  The new
 108    continuation will be added at the front.  */
 109
 110 void
 111 add_inferior_continuation (continuation_ftype *hook, void *args,
 112                            continuation_free_arg_ftype *free_arg)
 113 {
 114   struct inferior *inf = current_inferior ();
 115
 116   make_continuation (&inf->continuations, hook, args, free_arg);
 117 }
 118
 119 /* Do all continuations of the current inferior.  */
 120
 121 void
 122 do_all_inferior_continuations (int err)
 123 {
 124   struct inferior *inf = current_inferior ();
 125   do_my_continuations (&inf->continuations, err);
 126 }
 127
 128 /* Get rid of all the inferior-wide continuations of INF.  */
 129
 130 void
 131 discard_all_inferior_continuations (struct inferior *inf)
 132 {
 133   discard_my_continuations (&inf->continuations);
 134 }