1/* footnotes.c -- Some functions for manipulating footnotes.
2   $Id: footnotes.c,v 1.1 2004/10/28 18:14:09 zooey Exp $
3
4   Copyright (C) 1993, 97 Free Software Foundation, Inc.
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, or (at your option)
9   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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
19
20   Written by Brian Fox (bfox@ai.mit.edu). */
21
22#include "info.h"
23
24/* Non-zero means attempt to show footnotes when displaying a new window. */
25int auto_footnotes_p = 1;
26
27static char *footnote_nodename = "*Footnotes*";
28
29#define FOOTNOTE_HEADER_FORMAT \
30   "*** Footnotes appearing in the node \"%s\" ***\n"
31
32/* Find the window currently showing footnotes. */
33static WINDOW *
34find_footnotes_window ()
35{
36  WINDOW *win;
37
38  /* Try to find an existing window first. */
39  for (win = windows; win; win = win->next)
40    if (internal_info_node_p (win->node) &&
41        (strcmp (win->node->nodename, footnote_nodename) == 0))
42      break;
43
44  return (win);
45}
46
47/* Manufacture a node containing the footnotes of this node, and
48   return the manufactured node.  If NODE has no footnotes, return a
49   NULL pointer. */
50NODE *
51make_footnotes_node (node)
52     NODE *node;
53{
54  NODE *fn_node, *result = (NODE *)NULL;
55  long fn_start;
56
57  /* Make the initial assumption that the footnotes appear as simple
58     text within this windows node. */
59  fn_node = node;
60
61  /* See if this node contains the magic footnote label. */
62  fn_start =
63    info_search_in_node (FOOTNOTE_LABEL, node, 0, (WINDOW *)NULL, 1);
64
65  /* If it doesn't, check to see if it has an associated footnotes node. */
66  if (fn_start == -1)
67    {
68      REFERENCE **refs;
69
70      refs = info_xrefs_of_node (node);
71
72      if (refs)
73        {
74          register int i;
75          char *refname;
76
77          refname = (char *)xmalloc
78            (1 + strlen ("-Footnotes") + strlen (node->nodename));
79
80          strcpy (refname, node->nodename);
81          strcat (refname, "-Footnotes");
82
83          for (i = 0; refs[i]; i++)
84            if ((refs[i]->nodename != (char *)NULL) &&
85                (strcmp (refs[i]->nodename, refname) == 0))
86              {
87                char *filename;
88
89                filename = node->parent;
90                if (!filename)
91                  filename = node->filename;
92
93                fn_node = info_get_node (filename, refname);
94
95                if (fn_node)
96                  fn_start = 0;
97
98                break;
99              }
100
101          free (refname);
102          info_free_references (refs);
103        }
104    }
105
106  /* If we never found the start of a footnotes area, quit now. */
107  if (fn_start == -1)
108    return ((NODE *)NULL);
109
110  /* Make the new node. */
111  result = (NODE *)xmalloc (sizeof (NODE));
112  result->flags = 0;
113
114  /* Get the size of the footnotes appearing within this node. */
115  {
116    char *header;
117    long text_start = fn_start;
118
119    header = (char *)xmalloc
120      (1 + strlen (node->nodename) + strlen (FOOTNOTE_HEADER_FORMAT));
121    sprintf (header, FOOTNOTE_HEADER_FORMAT, node->nodename);
122
123    /* Move the start of the displayed text to right after the first line.
124       This effectively skips either "---- footno...", or "File: foo...". */
125    while (text_start < fn_node->nodelen)
126      if (fn_node->contents[text_start++] == '\n')
127        break;
128
129    result->nodelen = strlen (header) + fn_node->nodelen - text_start;
130
131    /* Set the contents of this node. */
132    result->contents = (char *)xmalloc (1 + result->nodelen);
133    sprintf (result->contents, "%s", header);
134    memcpy (result->contents + strlen (header),
135            fn_node->contents + text_start, fn_node->nodelen - text_start);
136
137    name_internal_node (result, footnote_nodename);
138    free (header);
139  }
140
141#if defined (NOTDEF)
142  /* If the footnotes were gleaned from the node that we were called with,
143     shorten the calling node's display length. */
144  if (fn_node == node)
145    narrow_node (node, 0, fn_start);
146#endif /* NOTDEF */
147
148  return (result);
149}
150
151/* Create or delete the footnotes window depending on whether footnotes
152   exist in WINDOW's node or not.  Returns FN_FOUND if footnotes were found
153   and displayed.  Returns FN_UNFOUND if there were no footnotes found
154   in WINDOW's node.  Returns FN_UNABLE if there were footnotes, but the
155   window to show them couldn't be made. */
156int
157info_get_or_remove_footnotes (window)
158     WINDOW *window;
159{
160  WINDOW *fn_win;
161  NODE *new_footnotes;
162
163  fn_win = find_footnotes_window ();
164
165  /* If we are in the footnotes window, change nothing. */
166  if (fn_win == window)
167    return (FN_FOUND);
168
169  /* Try to find footnotes for this window's node. */
170  new_footnotes = make_footnotes_node (window->node);
171
172  /* If there was a window showing footnotes, and there are no footnotes
173     for the current window, delete the old footnote window. */
174  if (fn_win && !new_footnotes)
175    {
176      if (windows->next)
177        info_delete_window_internal (fn_win);
178    }
179
180  /* If there are footnotes for this window's node, but no window around
181     showing footnotes, try to make a new window. */
182  if (new_footnotes && !fn_win)
183    {
184      WINDOW *old_active;
185      WINDOW *last, *win;
186
187      /* Always make this window be the last one appearing in the list.  Find
188         the last window in the chain. */
189      for (win = windows, last = windows; win; last = win, win = win->next);
190
191      /* Try to split this window, and make the split window the one to
192         contain the footnotes. */
193      old_active = active_window;
194      active_window = last;
195      fn_win = window_make_window (new_footnotes);
196      active_window = old_active;
197
198      if (!fn_win)
199        {
200          free (new_footnotes->contents);
201          free (new_footnotes);
202
203          /* If we are hacking automatic footnotes, and there are footnotes
204             but we couldn't display them, print a message to that effect. */
205          if (auto_footnotes_p)
206            inform_in_echo_area (_("Footnotes could not be displayed"));
207          return (FN_UNABLE);
208        }
209    }
210
211  /* If there are footnotes, and there is a window to display them,
212     make that window be the number of lines appearing in the footnotes. */
213  if (new_footnotes && fn_win)
214    {
215      window_set_node_of_window (fn_win, new_footnotes);
216
217      window_change_window_height
218        (fn_win, fn_win->line_count - fn_win->height);
219
220      remember_window_and_node (fn_win, new_footnotes);
221      add_gcable_pointer (new_footnotes->contents);
222    }
223
224  if (!new_footnotes)
225    return (FN_UNFOUND);
226  else
227    return (FN_FOUND);
228}
229
230/* Show the footnotes associated with this node in another window. */
231DECLARE_INFO_COMMAND (info_show_footnotes,
232   _("Show the footnotes associated with this node in another window"))
233{
234  /* A negative argument means just make the window go away. */
235  if (count < 0)
236    {
237      WINDOW *fn_win = find_footnotes_window ();
238
239      /* If there is an old footnotes window, and it isn't the only window
240         on the screen, delete it. */
241      if (fn_win && windows->next)
242        info_delete_window_internal (fn_win);
243    }
244  else
245    {
246      int result;
247
248      result = info_get_or_remove_footnotes (window);
249
250      switch (result)
251        {
252        case FN_UNFOUND:
253          info_error (NO_FOOT_NODE);
254          break;
255
256        case FN_UNABLE:
257          info_error (WIN_TOO_SMALL);
258          break;
259        }
260    }
261}
262