lib/readline/undo.c

   1 /* readline.c -- a general facility for reading lines of input
   2    with emacs style editing and completion. */
   3
   4 /* Copyright (C) 1987, 1989, 1992 Free Software Foundation, Inc.
   5
   6    This file is part of the GNU Readline Library, a library for
   7    reading lines of text with interactive input and history editing.
   8
   9    The GNU Readline Library is free software; you can redistribute it
  10    and/or modify it under the terms of the GNU General Public License
  11    as published by the Free Software Foundation; either version 2, or
  12    (at your option) any later version.
  13
  14    The GNU Readline Library is distributed in the hope that it will be
  15    useful, but WITHOUT ANY WARRANTY; without even the implied warranty
  16    of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18
  19    The GNU General Public License is often shipped with GNU software, and
  20    is generally kept in a file called COPYING or LICENSE.  If you do not
  21    have a copy of the license, write to the Free Software Foundation,
  22    59 Temple Place, Suite 330, Boston, MA 02111 USA. */
  23 #define READLINE_LIBRARY
  24
  25 #if defined (HAVE_CONFIG_H)
  26 #  include <config.h>
  27 #endif
  28
  29 #include <sys/types.h>
  30
  31 #if defined (HAVE_UNISTD_H)
  32 #  include <unistd.h>           /* for _POSIX_VERSION */
  33 #endif /* HAVE_UNISTD_H */
  34
  35 #if defined (HAVE_STDLIB_H)
  36 #  include <stdlib.h>
  37 #else
  38 #  include "ansi_stdlib.h"
  39 #endif /* HAVE_STDLIB_H */
  40
  41 #include <stdio.h>
  42
  43 /* System-specific feature definitions and include files. */
  44 #include "rldefs.h"
  45
  46 /* Some standard library routines. */
  47 #include "readline.h"
  48 #include "history.h"
  49
  50 #include "rlprivate.h"
  51
  52 #define SWAP(s, e)  do { int t; t = s; s = e; e = t; } while (0)
  53
  54 /* Non-zero tells rl_delete_text and rl_insert_text to not add to
  55    the undo list. */
  56 int _rl_doing_an_undo = 0;
  57
  58 /* How many unclosed undo groups we currently have. */
  59 int _rl_undo_group_level = 0;
  60
  61 /* The current undo list for THE_LINE. */
  62 UNDO_LIST *rl_undo_list = (UNDO_LIST *)NULL;
  63
  64 /* **************************************************************** */
  65 /*                                                                  */
  66 /*                      Undo, and Undoing                           */
  67 /*                                                                  */
  68 /* **************************************************************** */
  69
  70 /* Remember how to undo something.  Concatenate some undos if that
  71    seems right. */
  72 void
  73 rl_add_undo (what, start, end, text)
  74      enum undo_code what;
  75      int start, end;
  76      char *text;
  77 {
  78   UNDO_LIST *temp = (UNDO_LIST *)xmalloc (sizeof (UNDO_LIST));
  79   temp->what = what;
  80   temp->start = start;
  81   temp->end = end;
  82   temp->text = text;
  83   temp->next = rl_undo_list;
  84   rl_undo_list = temp;
  85 }
  86
  87 /* Free the existing undo list. */
  88 void
  89 rl_free_undo_list ()
  90 {
  91   while (rl_undo_list)
  92     {
  93       UNDO_LIST *release = rl_undo_list;
  94       rl_undo_list = rl_undo_list->next;
  95
  96       if (release->what == UNDO_DELETE)
  97         free (release->text);
  98
  99       free (release);
 100     }
 101   rl_undo_list = (UNDO_LIST *)NULL;
 102 }
 103
 104 /* Undo the next thing in the list.  Return 0 if there
 105    is nothing to undo, or non-zero if there was. */
 106 int
 107 rl_do_undo ()
 108 {
 109   UNDO_LIST *release;
 110   int waiting_for_begin, start, end;
 111
 112 #define TRANS(i) ((i) == -1 ? rl_point : ((i) == -2 ? rl_end : (i)))
 113
 114   start = end = waiting_for_begin = 0;
 115   do
 116     {
 117       if (!rl_undo_list)
 118         return (0);
 119
 120       _rl_doing_an_undo = 1;
 121       RL_SETSTATE(RL_STATE_UNDOING);
 122
 123       /* To better support vi-mode, a start or end value of -1 means
 124          rl_point, and a value of -2 means rl_end. */
 125       if (rl_undo_list->what == UNDO_DELETE || rl_undo_list->what == UNDO_INSERT)
 126         {
 127           start = TRANS (rl_undo_list->start);
 128           end = TRANS (rl_undo_list->end);
 129         }
 130
 131       switch (rl_undo_list->what)
 132         {
 133         /* Undoing deletes means inserting some text. */
 134         case UNDO_DELETE:
 135           rl_point = start;
 136           rl_insert_text (rl_undo_list->text);
 137           free (rl_undo_list->text);
 138           break;
 139
 140         /* Undoing inserts means deleting some text. */
 141         case UNDO_INSERT:
 142           rl_delete_text (start, end);
 143           rl_point = start;
 144           break;
 145
 146         /* Undoing an END means undoing everything 'til we get to a BEGIN. */
 147         case UNDO_END:
 148           waiting_for_begin++;
 149           break;
 150
 151         /* Undoing a BEGIN means that we are done with this group. */
 152         case UNDO_BEGIN:
 153           if (waiting_for_begin)
 154             waiting_for_begin--;
 155           else
 156             rl_ding ();
 157           break;
 158         }
 159
 160       _rl_doing_an_undo = 0;
 161       RL_UNSETSTATE(RL_STATE_UNDOING);
 162
 163       release = rl_undo_list;
 164       rl_undo_list = rl_undo_list->next;
 165       free (release);
 166     }
 167   while (waiting_for_begin);
 168
 169   return (1);
 170 }
 171 #undef TRANS
 172
 173 int
 174 _rl_fix_last_undo_of_type (type, start, end)
 175      int type, start, end;
 176 {
 177   UNDO_LIST *rl;
 178
 179   for (rl = rl_undo_list; rl; rl = rl->next)
 180     {
 181       if (rl->what == type)
 182         {
 183           rl->start = start;
 184           rl->end = end;
 185           return 0;
 186         }
 187     }
 188   return 1;
 189 }
 190
 191 /* Begin a group.  Subsequent undos are undone as an atomic operation. */
 192 int
 193 rl_begin_undo_group ()
 194 {
 195   rl_add_undo (UNDO_BEGIN, 0, 0, 0);
 196   _rl_undo_group_level++;
 197   return 0;
 198 }
 199
 200 /* End an undo group started with rl_begin_undo_group (). */
 201 int
 202 rl_end_undo_group ()
 203 {
 204   rl_add_undo (UNDO_END, 0, 0, 0);
 205   _rl_undo_group_level--;
 206   return 0;
 207 }
 208
 209 /* Save an undo entry for the text from START to END. */
 210 int
 211 rl_modifying (start, end)
 212      int start, end;
 213 {
 214   if (start > end)
 215     {
 216       SWAP (start, end);
 217     }
 218
 219   if (start != end)
 220     {
 221       char *temp = rl_copy_text (start, end);
 222       rl_begin_undo_group ();
 223       rl_add_undo (UNDO_DELETE, start, end, temp);
 224       rl_add_undo (UNDO_INSERT, start, end, (char *)NULL);
 225       rl_end_undo_group ();
 226     }
 227   return 0;
 228 }
 229
 230 /* Revert the current line to its previous state. */
 231 int
 232 rl_revert_line (count, key)
 233      int count, key;
 234 {
 235   if (!rl_undo_list)
 236     rl_ding ();
 237   else
 238     {
 239       while (rl_undo_list)
 240         rl_do_undo ();
 241     }
 242   return 0;
 243 }
 244
 245 /* Do some undoing of things that were done. */
 246 int
 247 rl_undo_command (count, key)
 248      int count, key;
 249 {
 250   if (count < 0)
 251     return 0;   /* Nothing to do. */
 252
 253   while (count)
 254     {
 255       if (rl_do_undo ())
 256         count--;
 257       else
 258         {
 259           rl_ding ();
 260           break;
 261         }
 262     }
 263   return 0;
 264 }