contrib/nvi2/common/mark.c

   1 /*-
   2  * Copyright (c) 1992, 1993, 1994
   3  *      The Regents of the University of California.  All rights reserved.
   4  * Copyright (c) 1992, 1993, 1994, 1995, 1996
   5  *      Keith Bostic.  All rights reserved.
   6  *
   7  * See the LICENSE file for redistribution information.
   8  */
   9
  10 #include "config.h"
  11
  12 #include <sys/types.h>
  13 #include <sys/queue.h>
  14 #include <sys/time.h>
  15
  16 #include <bitstring.h>
  17 #include <errno.h>
  18 #include <limits.h>
  19 #include <stdio.h>
  20 #include <stdlib.h>
  21 #include <string.h>
  22
  23 #include "common.h"
  24
  25 static LMARK *mark_find(SCR *, ARG_CHAR_T);
  26
  27 /*
  28  * Marks are maintained in a key sorted singly linked list.  We can't
  29  * use arrays because we have no idea how big an index key could be.
  30  * The underlying assumption is that users don't have more than, say,
  31  * 10 marks at any one time, so this will be is fast enough.
  32  *
  33  * Marks are fixed, and modifications to the line don't update the mark's
  34  * position in the line.  This can be hard.  If you add text to the line,
  35  * place a mark in that text, undo the addition and use ` to move to the
  36  * mark, the location will have disappeared.  It's tempting to try to adjust
  37  * the mark with the changes in the line, but this is hard to do, especially
  38  * if we've given the line to v_ntext.c:v_ntext() for editing.  Historic vi
  39  * would move to the first non-blank on the line when the mark location was
  40  * past the end of the line.  This can be complicated by deleting to a mark
  41  * that has disappeared using the ` command.  Historic vi treated this as
  42  * a line-mode motion and deleted the line.  This implementation complains to
  43  * the user.
  44  *
  45  * In historic vi, marks returned if the operation was undone, unless the
  46  * mark had been subsequently reset.  Tricky.  This is hard to start with,
  47  * but in the presence of repeated undo it gets nasty.  When a line is
  48  * deleted, we delete (and log) any marks on that line.  An undo will create
  49  * the mark.  Any mark creations are noted as to whether the user created
  50  * it or if it was created by an undo.  The former cannot be reset by another
  51  * undo, but the latter may.
  52  *
  53  * All of these routines translate ABSMARK2 to ABSMARK1.  Setting either of
  54  * the absolute mark locations sets both, so that "m'" and "m`" work like
  55  * they, ah, for lack of a better word, "should".
  56  */
  57
  58 /*
  59  * mark_init --
  60  *      Set up the marks.
  61  *
  62  * PUBLIC: int mark_init(SCR *, EXF *);
  63  */
  64 int
  65 mark_init(SCR *sp, EXF *ep)
  66 {
  67         /*
  68          * !!!
  69          * ep MAY NOT BE THE SAME AS sp->ep, DON'T USE THE LATTER.
  70          *
  71          * Set up the marks.
  72          */
  73         SLIST_INIT(ep->marks);
  74         return (0);
  75 }
  76
  77 /*
  78  * mark_end --
  79  *      Free up the marks.
  80  *
  81  * PUBLIC: int mark_end(SCR *, EXF *);
  82  */
  83 int
  84 mark_end(SCR *sp, EXF *ep)
  85 {
  86         LMARK *lmp;
  87
  88         /*
  89          * !!!
  90          * ep MAY NOT BE THE SAME AS sp->ep, DON'T USE THE LATTER.
  91          */
  92         while ((lmp = SLIST_FIRST(ep->marks)) != NULL) {
  93                 SLIST_REMOVE_HEAD(ep->marks, q);
  94                 free(lmp);
  95         }
  96         return (0);
  97 }
  98
  99 /*
 100  * mark_get --
 101  *      Get the location referenced by a mark.
 102  *
 103  * PUBLIC: int mark_get(SCR *, ARG_CHAR_T, MARK *, mtype_t);
 104  */
 105 int
 106 mark_get(SCR *sp, ARG_CHAR_T key, MARK *mp, mtype_t mtype)
 107 {
 108         LMARK *lmp;
 109
 110         if (key == ABSMARK2)
 111                 key = ABSMARK1;
 112
 113         lmp = mark_find(sp, key);
 114         if (lmp == NULL || lmp->name != key) {
 115                 msgq(sp, mtype, "017|Mark %s: not set", KEY_NAME(sp, key));
 116                 return (1);
 117         }
 118         if (F_ISSET(lmp, MARK_DELETED)) {
 119                 msgq(sp, mtype,
 120                     "018|Mark %s: the line was deleted", KEY_NAME(sp, key));
 121                 return (1);
 122         }
 123
 124         /*
 125          * !!!
 126          * The absolute mark is initialized to lno 1/cno 0, and historically
 127          * you could use it in an empty file.  Make such a mark always work.
 128          */
 129         if ((lmp->lno != 1 || lmp->cno != 0) && !db_exist(sp, lmp->lno)) {
 130                 msgq(sp, mtype,
 131                     "019|Mark %s: cursor position no longer exists",
 132                     KEY_NAME(sp, key));
 133                 return (1);
 134         }
 135         mp->lno = lmp->lno;
 136         mp->cno = lmp->cno;
 137         return (0);
 138 }
 139
 140 /*
 141  * mark_set --
 142  *      Set the location referenced by a mark.
 143  *
 144  * PUBLIC: int mark_set(SCR *, ARG_CHAR_T, MARK *, int);
 145  */
 146 int
 147 mark_set(SCR *sp, ARG_CHAR_T key, MARK *value, int userset)
 148 {
 149         LMARK *lmp, *lmt;
 150
 151         if (key == ABSMARK2)
 152                 key = ABSMARK1;
 153
 154         /*
 155          * The rules are simple.  If the user is setting a mark (if it's a
 156          * new mark this is always true), it always happens.  If not, it's
 157          * an undo, and we set it if it's not already set or if it was set
 158          * by a previous undo.
 159          */
 160         lmp = mark_find(sp, key);
 161         if (lmp == NULL || lmp->name != key) {
 162                 MALLOC_RET(sp, lmt, sizeof(LMARK));
 163                 if (lmp == NULL) {
 164                         SLIST_INSERT_HEAD(sp->ep->marks, lmt, q);
 165                 } else
 166                         SLIST_INSERT_AFTER(lmp, lmt, q);
 167                 lmp = lmt;
 168         } else if (!userset &&
 169             !F_ISSET(lmp, MARK_DELETED) && F_ISSET(lmp, MARK_USERSET))
 170                 return (0);
 171
 172         lmp->lno = value->lno;
 173         lmp->cno = value->cno;
 174         lmp->name = key;
 175         lmp->flags = userset ? MARK_USERSET : 0;
 176         return (0);
 177 }
 178
 179 /*
 180  * mark_find --
 181  *      Find the requested mark, or, the slot immediately before
 182  *      where it would go.
 183  */
 184 static LMARK *
 185 mark_find(SCR *sp, ARG_CHAR_T key)
 186 {
 187         LMARK *lmp, *lastlmp = NULL;
 188
 189         /*
 190          * Return the requested mark or the slot immediately before
 191          * where it should go.
 192          */
 193         SLIST_FOREACH(lmp, sp->ep->marks, q) {
 194                 if (lmp->name >= key)
 195                         return (lmp->name == key ? lmp : lastlmp);
 196                 lastlmp = lmp;
 197         }
 198         return (lastlmp);
 199 }
 200
 201 /*
 202  * mark_insdel --
 203  *      Update the marks based on an insertion or deletion.
 204  *
 205  * PUBLIC: int mark_insdel(SCR *, lnop_t, recno_t);
 206  */
 207 int
 208 mark_insdel(SCR *sp, lnop_t op, recno_t lno)
 209 {
 210         LMARK *lmp;
 211         recno_t lline;
 212
 213         switch (op) {
 214         case LINE_APPEND:
 215                 /* All insert/append operations are done as inserts. */
 216                 abort();
 217         case LINE_DELETE:
 218                 SLIST_FOREACH(lmp, sp->ep->marks, q)
 219                         if (lmp->lno >= lno)
 220                                 if (lmp->lno == lno) {
 221                                         F_SET(lmp, MARK_DELETED);
 222                                         (void)log_mark(sp, lmp);
 223                                 } else
 224                                         --lmp->lno;
 225                 break;
 226         case LINE_INSERT:
 227                 /*
 228                  * XXX
 229                  * Very nasty special case.  If the file was empty, then we're
 230                  * adding the first line, which is a replacement.  So, we don't
 231                  * modify the marks.  This is a hack to make:
 232                  *
 233                  *      mz:r!echo foo<carriage-return>'z
 234                  *
 235                  * work, i.e. historically you could mark the "line" in an empty
 236                  * file and replace it, and continue to use the mark.  Insane,
 237                  * well, yes, I know, but someone complained.
 238                  *
 239                  * Check for line #2 before going to the end of the file.
 240                  */
 241                 if (!db_exist(sp, 2)) {
 242                         if (db_last(sp, &lline))
 243                                 return (1);
 244                         if (lline == 1)
 245                                 return (0);
 246                 }
 247
 248                 SLIST_FOREACH(lmp, sp->ep->marks, q)
 249                         if (lmp->lno >= lno)
 250                                 ++lmp->lno;
 251                 break;
 252         case LINE_RESET:
 253                 break;
 254         }
 255         return (0);
 256 }