contrib/texinfo-4/makeinfo/html.c

   1 /* html.c -- html-related utilities.
   2    $Id: html.c,v 1.28 2004/12/06 01:13:06 karl Exp $
   3
   4    Copyright (C) 1999, 2000, 2001, 2002, 2003, 2004 Free Software
   5    Foundation, Inc.
   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 2, or (at your option)
  10    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, write to the Free Software Foundation,
  19    Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  20
  21 #include "system.h"
  22 #include "cmds.h"
  23 #include "files.h"
  24 #include "html.h"
  25 #include "lang.h"
  26 #include "makeinfo.h"
  27 #include "node.h"
  28 #include "sectioning.h"
  29
  30 \f
  31 /* Append CHAR to BUFFER, (re)allocating as necessary.  We don't handle
  32    null characters.  */
  33
  34 typedef struct
  35 {
  36   unsigned size;    /* allocated */
  37   unsigned length;  /* used */
  38   char *buffer;
  39 } buffer_type;
  40
  41 static buffer_type *
  42 init_buffer (void)
  43 {
  44   buffer_type *buf = xmalloc (sizeof (buffer_type));
  45   buf->length = 0;
  46   buf->size = 0;
  47   buf->buffer = NULL;
  48
  49   return buf;
  50 }
  51
  52 static void
  53 append_char (buffer_type *buf, int c)
  54 {
  55   buf->length++;
  56   if (buf->length >= buf->size)
  57     {
  58       buf->size += 100;
  59       buf->buffer = xrealloc (buf->buffer, buf->size);
  60     }
  61   buf->buffer[buf->length - 1] = c;
  62   buf->buffer[buf->length] = 0;
  63 }
  64
  65 /* Read the cascading style-sheet file FILENAME.  Write out any @import
  66    commands, which must come first, by the definition of css.  If the
  67    file contains any actual css code following the @imports, return it;
  68    else return NULL.  */
  69 static char *
  70 process_css_file (char *filename)
  71 {
  72   int c;
  73   int lastchar = 0;
  74   FILE *f;
  75   buffer_type *import_text = init_buffer ();
  76   buffer_type *inline_text = init_buffer ();
  77   unsigned lineno = 1;
  78   enum { null_state, comment_state, import_state, inline_state } state
  79     = null_state, prev_state;
  80
  81   prev_state = null_state;
  82
  83   /* read from stdin if `-' is the filename.  */
  84   f = STREQ (filename, "-") ? stdin : fopen (filename, "r");
  85   if (!f)
  86     {
  87       error (_("%s: could not open --css-file: %s"), progname, filename);
  88       return NULL;
  89     }
  90
  91   /* Read the file.  The @import statements must come at the beginning,
  92      with only whitespace and comments allowed before any inline css code.  */
  93   while ((c = getc (f)) >= 0)
  94     {
  95       if (c == '\n')
  96         lineno++;
  97
  98       switch (state)
  99         {
 100         case null_state: /* between things */
 101           if (c == '@')
 102             { /* Only @import and @charset should switch into
 103                  import_state, other @-commands, such as @media, should
 104                  put us into inline_state.  I don't think any other css
 105                  @-commands start with `i' or `c', although of course
 106                  this will break when such a command is defined.  */
 107               int nextchar = getc (f);
 108               if (nextchar == 'i' || nextchar == 'c')
 109                 {
 110                   append_char (import_text, c);
 111                   state = import_state;
 112                 }
 113               else
 114                 {
 115                   ungetc (nextchar, f);  /* wasn't an @import */
 116                   state = inline_state;
 117                 }
 118             }
 119           else if (c == '/')
 120             { /* possible start of a comment */
 121               int nextchar = getc (f);
 122               if (nextchar == '*')
 123                 state = comment_state;
 124               else
 125                 {
 126                   ungetc (nextchar, f); /* wasn't a comment */
 127                   state = inline_state;
 128                 }
 129             }
 130           else if (isspace (c))
 131             ; /* skip whitespace; maybe should use c_isspace?  */
 132
 133           else
 134             /* not an @import, not a comment, not whitespace: we must
 135                have started the inline text.  */
 136             state = inline_state;
 137
 138           if (state == inline_state)
 139             append_char (inline_text, c);
 140
 141           if (state != null_state)
 142             prev_state = null_state;
 143           break;
 144
 145         case comment_state:
 146           if (c == '/' && lastchar == '*')
 147             state = prev_state;  /* end of comment */
 148           break;  /* else ignore this comment char */
 149
 150         case import_state:
 151           append_char (import_text, c);  /* include this import char */
 152           if (c == ';')
 153             { /* done with @import */
 154               append_char (import_text, '\n');  /* make the output nice */
 155               state = null_state;
 156               prev_state = import_state;
 157             }
 158           break;
 159
 160         case inline_state:
 161           /* No harm in writing out comments, so don't bother parsing
 162              them out, just append everything.  */
 163           append_char (inline_text, c);
 164           break;
 165         }
 166
 167       lastchar = c;
 168     }
 169
 170   /* Reached the end of the file.  We should not be still in a comment.  */
 171   if (state == comment_state)
 172     warning (_("%s:%d: --css-file ended in comment"), filename, lineno);
 173
 174   /* Write the @import text, if any.  */
 175   if (import_text->buffer)
 176     {
 177       add_word (import_text->buffer);
 178       free (import_text->buffer);
 179       free (import_text);
 180     }
 181
 182   /* We're wasting the buffer struct memory, but so what.  */
 183   return inline_text->buffer;
 184 }
 185 \f
 186 HSTACK *htmlstack = NULL;
 187
 188 /* See html.h.  */
 189 int html_output_head_p = 0;
 190 int html_title_written = 0;
 191
 192 void
 193 html_output_head (void)
 194 {
 195   static const char *html_title = NULL;
 196   char *encoding;
 197
 198   if (html_output_head_p)
 199     return;
 200   html_output_head_p = 1;
 201
 202   encoding = current_document_encoding ();
 203
 204   /* The <title> should not have markup, so use text_expansion.  */
 205   if (!html_title)
 206     html_title = escape_string (title ?
 207         text_expansion (title) : (char *) _("Untitled"));
 208
 209   /* Make sure this is the very first string of the output document.  */
 210   output_paragraph_offset = 0;
 211
 212   add_html_block_elt_args ("<html lang=\"%s\">\n<head>\n",
 213       language_table[language_code].abbrev);
 214
 215   /* When splitting, add current node's name to title if it's available and not
 216      Top.  */
 217   if (splitting && current_node && !STREQ (current_node, "Top"))
 218     add_word_args ("<title>%s - %s</title>\n",
 219         escape_string (xstrdup (current_node)), html_title);
 220   else
 221     add_word_args ("<title>%s</title>\n",  html_title);
 222
 223   add_word ("<meta http-equiv=\"Content-Type\" content=\"text/html");
 224   if (encoding && *encoding)
 225     add_word_args ("; charset=%s", encoding);
 226
 227   add_word ("\">\n");
 228
 229   if (!document_description)
 230     document_description = html_title;
 231
 232   add_word_args ("<meta name=\"description\" content=\"%s\">\n",
 233                  document_description);
 234   add_word_args ("<meta name=\"generator\" content=\"makeinfo %s\">\n",
 235                  VERSION);
 236
 237   /* Navigation bar links.  */
 238   if (!splitting)
 239     add_word ("<link title=\"Top\" rel=\"top\" href=\"#Top\">\n");
 240   else if (tag_table)
 241     {
 242       /* Always put a top link.  */
 243       add_word ("<link title=\"Top\" rel=\"start\" href=\"index.html#Top\">\n");
 244
 245       /* We already have a top link, avoid duplication.  */
 246       if (tag_table->up && !STREQ (tag_table->up, "Top"))
 247         add_link (tag_table->up, "rel=\"up\"");
 248
 249       if (tag_table->prev)
 250         add_link (tag_table->prev, "rel=\"prev\"");
 251
 252       if (tag_table->next)
 253         add_link (tag_table->next, "rel=\"next\"");
 254
 255       /* fixxme: Look for a way to put links to various indices in the
 256          document.  Also possible candidates to be added here are First and
 257          Last links.  */
 258     }
 259   else
 260     {
 261       /* We are splitting, but we neither have a tag_table.  So this must be
 262          index.html.  So put a link to Top. */
 263       add_word ("<link title=\"Top\" rel=\"start\" href=\"#Top\">\n");
 264     }
 265
 266   add_word ("<link href=\"http://www.gnu.org/software/texinfo/\" \
 267 rel=\"generator-home\" title=\"Texinfo Homepage\">\n");
 268
 269   if (copying_text)
 270     { /* It is not ideal that we include the html markup here within
 271          <head>, so we use text_expansion.  */
 272       insert_string ("<!--\n");
 273       insert_string (text_expansion (copying_text));
 274       insert_string ("-->\n");
 275     }
 276
 277   /* Put the style definitions in a comment for the sake of browsers
 278      that don't support <style>.  */
 279   add_word ("<meta http-equiv=\"Content-Style-Type\" content=\"text/css\">\n");
 280   add_word ("<style type=\"text/css\"><!--\n");
 281
 282   {
 283     char *css_inline = NULL;
 284
 285     if (css_include)
 286       /* This writes out any @import commands from the --css-file,
 287          and returns any actual css code following the imports.  */
 288       css_inline = process_css_file (css_include);
 289
 290     /* This seems cleaner than adding <br>'s at the end of each line for
 291        these "roman" displays.  It's hardly the end of the world if the
 292        browser doesn't do <style>s, in any case; they'll just come out in
 293        typewriter.  */
 294 #define CSS_FONT_INHERIT "font-family:inherit"
 295     add_word_args ("  pre.display { %s }\n", CSS_FONT_INHERIT);
 296     add_word_args ("  pre.format  { %s }\n", CSS_FONT_INHERIT);
 297
 298     /* Alternatively, we could do <font size=-1> in insertion.c, but this
 299        way makes it easier to override.  */
 300 #define CSS_FONT_SMALLER "font-size:smaller"
 301     add_word_args ("  pre.smalldisplay { %s; %s }\n", CSS_FONT_INHERIT,
 302                    CSS_FONT_SMALLER);
 303     add_word_args ("  pre.smallformat  { %s; %s }\n", CSS_FONT_INHERIT,
 304                    CSS_FONT_SMALLER);
 305     add_word_args ("  pre.smallexample { %s }\n", CSS_FONT_SMALLER);
 306     add_word_args ("  pre.smalllisp    { %s }\n", CSS_FONT_SMALLER);
 307
 308     /* Since HTML doesn't have a sc element, we use span with a bit of
 309        CSS spice instead.  */
 310 #define CSS_FONT_SMALL_CAPS "font-variant:small-caps"
 311     add_word_args ("  span.sc    { %s }\n", CSS_FONT_SMALL_CAPS);
 312
 313     /* Roman (default) font class, closest we can come.  */
 314 #define CSS_FONT_ROMAN "font-family:serif; font-weight:normal;"
 315     add_word_args ("  span.roman { %s } \n", CSS_FONT_ROMAN);
 316
 317     /* Sans serif font class.  */
 318 #define CSS_FONT_SANSSERIF "font-family:sans-serif; font-weight:normal;"
 319     add_word_args ("  span.sansserif { %s } \n", CSS_FONT_SANSSERIF);
 320
 321     /* Write out any css code from the user's --css-file.  */
 322     if (css_inline)
 323       insert_string (css_inline);
 324
 325     add_word ("--></style>\n");
 326   }
 327
 328   add_word ("</head>\n<body>\n");
 329
 330   if (title && !html_title_written && titlepage_cmd_present)
 331     {
 332       add_word_args ("<h1 class=\"settitle\">%s</h1>\n", html_title);
 333       html_title_written = 1;
 334     }
 335
 336   free (encoding);
 337 }
 338 \f
 339 /* Escape HTML special characters in the string if necessary,
 340    returning a pointer to a possibly newly-allocated one. */
 341 char *
 342 escape_string (char *string)
 343 {
 344   char *newstring;
 345   int i = 0, newlen = 0;
 346
 347   do
 348     {
 349       /* Find how much to allocate. */
 350       switch (string[i])
 351         {
 352         case '"':
 353           newlen += 6;          /* `&quot;' */
 354           break;
 355         case '&':
 356           newlen += 5;          /* `&amp;' */
 357           break;
 358         case '<':
 359         case '>':
 360           newlen += 4;          /* `&lt;', `&gt;' */
 361           break;
 362         default:
 363           newlen++;
 364         }
 365     }
 366   while (string[i++]);
 367
 368   if (newlen == i) return string; /* Already OK. */
 369
 370   newstring = xmalloc (newlen);
 371   i = 0;
 372   do
 373     {
 374       switch (string[i])
 375         {
 376         case '"':
 377           strcpy (newstring, "&quot;");
 378           newstring += 6;
 379           break;
 380         case '&':
 381           strcpy (newstring, "&amp;");
 382           newstring += 5;
 383           break;
 384         case '<':
 385           strcpy (newstring, "&lt;");
 386           newstring += 4;
 387           break;
 388         case '>':
 389           strcpy (newstring, "&gt;");
 390           newstring += 4;
 391           break;
 392         default:
 393           newstring[0] = string[i];
 394           newstring++;
 395         }
 396     }
 397   while (string[i++]);
 398   free (string);
 399   return newstring - newlen;
 400 }
 401 \f
 402 /* Save current tag.  */
 403 static void
 404 push_tag (char *tag, char *attribs)
 405 {
 406   HSTACK *newstack = xmalloc (sizeof (HSTACK));
 407
 408   newstack->tag = tag;
 409   newstack->attribs = xstrdup (attribs);
 410   newstack->next = htmlstack;
 411   htmlstack = newstack;
 412 }
 413
 414 /* Get last tag.  */
 415 static void
 416 pop_tag (void)
 417 {
 418   HSTACK *tos = htmlstack;
 419
 420   if (!tos)
 421     {
 422       line_error (_("[unexpected] no html tag to pop"));
 423       return;
 424     }
 425
 426   free (htmlstack->attribs);
 427
 428   htmlstack = htmlstack->next;
 429   free (tos);
 430 }
 431
 432 /* Check if tag is an empty or a whitespace only element.
 433    If so, remove it, keeping whitespace intact.  */
 434 int
 435 rollback_empty_tag (char *tag)
 436 {
 437   int check_position = output_paragraph_offset;
 438   int taglen = strlen (tag);
 439   int rollback_happened = 0;
 440   char *contents = "";
 441   char *contents_canon_white = "";
 442
 443   /* If output_paragraph is empty, we cannot rollback :-\  */
 444   if (output_paragraph_offset <= 0)
 445     return 0;
 446
 447   /* Find the end of the previous tag.  */
 448   while (output_paragraph[check_position-1] != '>' && check_position > 0)
 449     check_position--;
 450
 451   /* Save stuff between tag's end to output_paragraph's end.  */
 452   if (check_position != output_paragraph_offset)
 453     {
 454       contents = xmalloc (output_paragraph_offset - check_position + 1);
 455       memcpy (contents, output_paragraph + check_position,
 456           output_paragraph_offset - check_position);
 457
 458       contents[output_paragraph_offset - check_position] = '\0';
 459
 460       contents_canon_white = xstrdup (contents);
 461       canon_white (contents_canon_white);
 462     }
 463
 464   /* Find the start of the previous tag.  */
 465   while (output_paragraph[check_position-1] != '<' && check_position > 0)
 466     check_position--;
 467
 468   /* Check to see if this is the tag.  */
 469   if (strncmp ((char *) output_paragraph + check_position, tag, taglen) == 0
 470       && (whitespace (output_paragraph[check_position + taglen])
 471           || output_paragraph[check_position + taglen] == '>'))
 472     {
 473       if (!contents_canon_white || !*contents_canon_white)
 474         {
 475           /* Empty content after whitespace removal, so roll it back.  */
 476           output_paragraph_offset = check_position - 1;
 477           rollback_happened = 1;
 478
 479           /* Original contents may not be empty (whitespace.)  */
 480           if (contents && *contents)
 481             {
 482               insert_string (contents);
 483               free (contents);
 484             }
 485         }
 486     }
 487
 488   return rollback_happened;
 489 }
 490
 491 /* Open or close TAG according to START_OR_END. */
 492 void
 493 #if defined (VA_FPRINTF) && __STDC__
 494 insert_html_tag_with_attribute (int start_or_end, char *tag, char *format, ...)
 495 #else
 496 insert_html_tag_with_attribute (start_or_end, tag, format, va_alist)
 497      int start_or_end;
 498      char *tag;
 499      char *format;
 500      va_dcl
 501 #endif
 502 {
 503   char *old_tag = NULL;
 504   char *old_attribs = NULL;
 505   char formatted_attribs[2000]; /* xx no fixed limits */
 506   int do_return = 0;
 507   extern int in_html_elt;
 508
 509   if (start_or_end != START)
 510     pop_tag ();
 511
 512   if (htmlstack)
 513     {
 514       old_tag = htmlstack->tag;
 515       old_attribs = htmlstack->attribs;
 516     }
 517
 518   if (format)
 519     {
 520 #ifdef VA_SPRINTF
 521       va_list ap;
 522 #endif
 523
 524       VA_START (ap, format);
 525 #ifdef VA_SPRINTF
 526       VA_SPRINTF (formatted_attribs, format, ap);
 527 #else
 528       sprintf (formatted_attribs, format, a1, a2, a3, a4, a5, a6, a7, a8);
 529 #endif
 530       va_end (ap);
 531     }
 532   else
 533     formatted_attribs[0] = '\0';
 534
 535   /* Exception: can nest multiple spans.  */
 536   if (htmlstack
 537       && STREQ (htmlstack->tag, tag)
 538       && !(STREQ (tag, "span") && STREQ (old_attribs, formatted_attribs)))
 539     do_return = 1;
 540
 541   if (start_or_end == START)
 542     push_tag (tag, formatted_attribs);
 543
 544   if (do_return)
 545     return;
 546
 547   in_html_elt++;
 548
 549   /* texinfo.tex doesn't support more than one font attribute
 550      at the same time.  */
 551   if ((start_or_end == START) && old_tag && *old_tag
 552       && !rollback_empty_tag (old_tag))
 553     add_word_args ("</%s>", old_tag);
 554
 555   if (*tag)
 556     {
 557       if (start_or_end == START)
 558         add_word_args (format ? "<%s %s>" : "<%s>", tag, formatted_attribs);
 559       else if (!rollback_empty_tag (tag))
 560         /* Insert close tag only if we didn't rollback,
 561            in which case the opening tag is removed.  */
 562         add_word_args ("</%s>", tag);
 563     }
 564
 565   if ((start_or_end != START) && old_tag && *old_tag)
 566     add_word_args (strlen (old_attribs) > 0 ? "<%s %s>" : "<%s>",
 567         old_tag, old_attribs);
 568
 569   in_html_elt--;
 570 }
 571
 572 void
 573 insert_html_tag (int start_or_end, char *tag)
 574 {
 575   insert_html_tag_with_attribute (start_or_end, tag, NULL);
 576 }
 577 \f
 578 /* Output an HTML <link> to the filename for NODE, including the
 579    other string as extra attributes. */
 580 void
 581 add_link (char *nodename, char *attributes)
 582 {
 583   if (nodename)
 584     {
 585       add_html_elt ("<link ");
 586       add_word_args ("%s", attributes);
 587       add_word_args (" href=\"");
 588       add_anchor_name (nodename, 1);
 589       add_word_args ("\" title=\"%s\">\n", nodename);
 590     }
 591 }
 592
 593 /* Output NAME with characters escaped as appropriate for an anchor
 594    name, i.e., escape URL special characters with our _00hh convention
 595    if OLD is zero.  (See the manual for details on the new scheme.)
 596
 597    If OLD is nonzero, generate the node name with the 4.6-and-earlier
 598    convention of %hh (and more special characters output as-is, notably
 599    - and *).  This is only so that external references to old names can
 600    still work with HTML generated by the new makeinfo; the gcc folks
 601    needed this.  Our own HTML does not refer to these names.  */
 602
 603 void
 604 add_escaped_anchor_name (char *name, int old)
 605 {
 606   canon_white (name);
 607
 608   if (!old && !strchr ("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ",
 609                        *name))
 610     { /* XHTML does not allow anything but an ASCII letter to start an
 611          identifier.  Therefore kludge in this constant string if we
 612          have a nonletter.  */
 613       add_word ("g_t");
 614     }
 615
 616   for (; *name; name++)
 617     {
 618       if (cr_or_whitespace (*name))
 619         add_char ('-');
 620
 621       else if (!old && !URL_SAFE_CHAR (*name))
 622         /* Cast so characters with the high bit set are treated as >128,
 623            for example o-umlaut should be 246, not -10.  */
 624         add_word_args ("_00%x", (unsigned char) *name);
 625
 626       else if (old && !URL_SAFE_CHAR (*name) && !OLD_URL_SAFE_CHAR (*name))
 627         /* Different output convention, but still cast as above.  */
 628         add_word_args ("%%%x", (unsigned char) *name);
 629
 630       else
 631         add_char (*name);
 632     }
 633 }
 634
 635 /* Insert the text for the name of a reference in an HTML anchor
 636    appropriate for NODENAME.
 637
 638    If HREF is zero, generate text for name= in the new node name
 639      conversion convention.
 640    If HREF is negative, generate text for name= in the old convention.
 641    If HREF is positive, generate the name for an href= attribute, i.e.,
 642      including the `#' if it's an internal reference.   */
 643 void
 644 add_anchor_name (char *nodename, int href)
 645 {
 646   if (href > 0)
 647     {
 648       if (splitting)
 649         add_url_name (nodename, href);
 650       add_char ('#');
 651     }
 652   /* Always add NODENAME, so that the reference would pinpoint the
 653      exact node on its file.  This is so several nodes could share the
 654      same file, in case of file-name clashes, but also for more
 655      accurate browser positioning.  */
 656   if (strcasecmp (nodename, "(dir)") == 0)
 657     /* Strip the parens, but keep the original letter-case.  */
 658     add_word_args ("%.3s", nodename + 1);
 659   else if (strcasecmp (nodename, "top") == 0)
 660     add_word ("Top");
 661   else
 662     add_escaped_anchor_name (nodename, href < 0);
 663 }
 664
 665 /* Insert the text for the name of a reference in an HTML url, aprropriate
 666    for NODENAME */
 667 void
 668 add_url_name (char *nodename, int href)
 669 {
 670     add_nodename_to_filename (nodename, href);
 671 }
 672
 673 /* Convert non [A-Za-z0-9] to _00xx, where xx means the hexadecimal
 674    representation of the ASCII character.  Also convert spaces and
 675    newlines to dashes.  */
 676 static void
 677 fix_filename (char *filename)
 678 {
 679   int i;
 680   int len = strlen (filename);
 681   char *oldname = xstrdup (filename);
 682
 683   *filename = '\0';
 684
 685   for (i = 0; i < len; i++)
 686     {
 687       if (cr_or_whitespace (oldname[i]))
 688         strcat (filename, "-");
 689       else if (URL_SAFE_CHAR (oldname[i]))
 690         strncat (filename, (char *) oldname + i, 1);
 691       else
 692         {
 693           char *hexchar = xmalloc (6 * sizeof (char));
 694           sprintf (hexchar, "_00%x", (unsigned char) oldname[i]);
 695           strcat (filename, hexchar);
 696           free (hexchar);
 697         }
 698
 699       /* Check if we are nearing boundaries.  */
 700       if (strlen (filename) >= PATH_MAX - 20)
 701         break;
 702     }
 703
 704   free (oldname);
 705 }
 706
 707 /* As we can't look-up a (forward-referenced) nodes' html filename
 708    from the tentry, we take the easy way out.  We assume that
 709    nodenames are unique, and generate the html filename from the
 710    nodename, that's always known.  */
 711 static char *
 712 nodename_to_filename_1 (char *nodename, int href)
 713 {
 714   char *p;
 715   char *filename;
 716   char dirname[PATH_MAX];
 717
 718   if (strcasecmp (nodename, "Top") == 0)
 719     {
 720       /* We want to convert references to the Top node into
 721          "index.html#Top".  */
 722       if (href)
 723         filename = xstrdup ("index.html"); /* "#Top" is added by our callers */
 724       else
 725         filename = xstrdup ("Top");
 726     }
 727   else if (strcasecmp (nodename, "(dir)") == 0)
 728     /* We want to convert references to the (dir) node into
 729        "../index.html".  */
 730     filename = xstrdup ("../index.html");
 731   else
 732     {
 733       filename = xmalloc (PATH_MAX);
 734       dirname[0] = '\0';
 735       *filename = '\0';
 736
 737       /* Check for external reference: ``(info-document)node-name''
 738          Assume this node lives at: ``../info-document/node-name.html''
 739
 740          We need to handle the special case (sigh): ``(info-document)'',
 741          ie, an external top-node, which should translate to:
 742          ``../info-document/info-document.html'' */
 743
 744       p = nodename;
 745       if (*nodename == '(')
 746         {
 747           int length;
 748
 749           p = strchr (nodename, ')');
 750           if (p == NULL)
 751             {
 752               line_error (_("[unexpected] invalid node name: `%s'"), nodename);
 753               xexit (1);
 754             }
 755
 756           length = p - nodename - 1;
 757           if (length > 5 &&
 758               FILENAME_CMPN (p - 5, ".info", 5) == 0)
 759             length -= 5;
 760           /* This is for DOS, and also for Windows and GNU/Linux
 761              systems that might have Info files copied from a DOS 8+3
 762              filesystem.  */
 763           if (length > 4 &&
 764               FILENAME_CMPN (p - 4, ".inf", 4) == 0)
 765             length -= 4;
 766           strcpy (filename, "../");
 767           strncpy (dirname, nodename + 1, length);
 768           *(dirname + length) = '\0';
 769           fix_filename (dirname);
 770           strcat (filename, dirname);
 771           strcat (filename, "/");
 772           p++;
 773         }
 774
 775       /* In the case of just (info-document), there will be nothing
 776          remaining, and we will refer to ../info-document/, which will
 777          work fine.  */
 778       strcat (filename, p);
 779       if (*p)
 780         {
 781           /* Hmm */
 782           fix_filename (filename + strlen (filename) - strlen (p));
 783           strcat (filename, ".html");
 784         }
 785     }
 786
 787   /* Produce a file name suitable for the underlying filesystem.  */
 788   normalize_filename (filename);
 789
 790 #if 0
 791   /* We add ``#Nodified-filename'' anchor to external references to be
 792      prepared for non-split HTML support.  Maybe drop this. */
 793   if (href && *dirname)
 794     {
 795       strcat (filename, "#");
 796       strcat (filename, p);
 797       /* Hmm, again */
 798       fix_filename (filename + strlen (filename) - strlen (p));
 799     }
 800 #endif
 801
 802   return filename;
 803 }
 804
 805 /* If necessary, ie, if current filename != filename of node, output
 806    the node name.  */
 807 void
 808 add_nodename_to_filename (char *nodename, int href)
 809 {
 810   /* for now, don't check: always output filename */
 811   char *filename = nodename_to_filename_1 (nodename, href);
 812   add_word (filename);
 813   free (filename);
 814 }
 815
 816 char *
 817 nodename_to_filename (char *nodename)
 818 {
 819   /* The callers of nodename_to_filename use the result to produce
 820      <a href=, so call nodename_to_filename_1 with last arg non-zero.  */
 821   return nodename_to_filename_1 (nodename, 1);
 822 }