html.c

   1 /*      $Id: html.c,v 1.258 2019/09/01 15:12:19 schwarze Exp $ */
   2 /*
   3  * Copyright (c) 2008-2011, 2014 Kristaps Dzonsons <kristaps@bsd.lv>
   4  * Copyright (c) 2011-2015, 2017-2019 Ingo Schwarze <schwarze@openbsd.org>
   5  *
   6  * Permission to use, copy, modify, and distribute this software for any
   7  * purpose with or without fee is hereby granted, provided that the above
   8  * copyright notice and this permission notice appear in all copies.
   9  *
  10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHORS DISCLAIM ALL WARRANTIES
  11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR
  13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  14  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  15  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  16  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  17  */
  18 #include "config.h"
  19
  20 #include <sys/types.h>
  21 #include <sys/stat.h>
  22
  23 #include <assert.h>
  24 #include <ctype.h>
  25 #include <stdarg.h>
  26 #include <stddef.h>
  27 #include <stdio.h>
  28 #include <stdint.h>
  29 #include <stdlib.h>
  30 #include <string.h>
  31 #include <unistd.h>
  32
  33 #include "mandoc_aux.h"
  34 #include "mandoc_ohash.h"
  35 #include "mandoc.h"
  36 #include "roff.h"
  37 #include "out.h"
  38 #include "html.h"
  39 #include "manconf.h"
  40 #include "main.h"
  41
  42 struct  htmldata {
  43         const char       *name;
  44         int               flags;
  45 #define HTML_INPHRASE    (1 << 0)  /* Can appear in phrasing context. */
  46 #define HTML_TOPHRASE    (1 << 1)  /* Establishes phrasing context. */
  47 #define HTML_NOSTACK     (1 << 2)  /* Does not have an end tag. */
  48 #define HTML_NLBEFORE    (1 << 3)  /* Output line break before opening. */
  49 #define HTML_NLBEGIN     (1 << 4)  /* Output line break after opening. */
  50 #define HTML_NLEND       (1 << 5)  /* Output line break before closing. */
  51 #define HTML_NLAFTER     (1 << 6)  /* Output line break after closing. */
  52 #define HTML_NLAROUND    (HTML_NLBEFORE | HTML_NLAFTER)
  53 #define HTML_NLINSIDE    (HTML_NLBEGIN | HTML_NLEND)
  54 #define HTML_NLALL       (HTML_NLAROUND | HTML_NLINSIDE)
  55 #define HTML_INDENT      (1 << 7)  /* Indent content by two spaces. */
  56 #define HTML_NOINDENT    (1 << 8)  /* Exception: never indent content. */
  57 };
  58
  59 static  const struct htmldata htmltags[TAG_MAX] = {
  60         {"html",        HTML_NLALL},
  61         {"head",        HTML_NLALL | HTML_INDENT},
  62         {"meta",        HTML_NOSTACK | HTML_NLALL},
  63         {"link",        HTML_NOSTACK | HTML_NLALL},
  64         {"style",       HTML_NLALL | HTML_INDENT},
  65         {"title",       HTML_NLAROUND},
  66         {"body",        HTML_NLALL},
  67         {"div",         HTML_NLAROUND},
  68         {"section",     HTML_NLALL},
  69         {"table",       HTML_NLALL | HTML_INDENT},
  70         {"tr",          HTML_NLALL | HTML_INDENT},
  71         {"td",          HTML_NLAROUND},
  72         {"li",          HTML_NLAROUND | HTML_INDENT},
  73         {"ul",          HTML_NLALL | HTML_INDENT},
  74         {"ol",          HTML_NLALL | HTML_INDENT},
  75         {"dl",          HTML_NLALL | HTML_INDENT},
  76         {"dt",          HTML_NLAROUND},
  77         {"dd",          HTML_NLAROUND | HTML_INDENT},
  78         {"h1",          HTML_TOPHRASE | HTML_NLAROUND},
  79         {"h2",          HTML_TOPHRASE | HTML_NLAROUND},
  80         {"p",           HTML_TOPHRASE | HTML_NLAROUND | HTML_INDENT},
  81         {"pre",         HTML_TOPHRASE | HTML_NLALL | HTML_NOINDENT},
  82         {"a",           HTML_INPHRASE | HTML_TOPHRASE},
  83         {"b",           HTML_INPHRASE | HTML_TOPHRASE},
  84         {"cite",        HTML_INPHRASE | HTML_TOPHRASE},
  85         {"code",        HTML_INPHRASE | HTML_TOPHRASE},
  86         {"i",           HTML_INPHRASE | HTML_TOPHRASE},
  87         {"small",       HTML_INPHRASE | HTML_TOPHRASE},
  88         {"span",        HTML_INPHRASE | HTML_TOPHRASE},
  89         {"var",         HTML_INPHRASE | HTML_TOPHRASE},
  90         {"br",          HTML_INPHRASE | HTML_NOSTACK | HTML_NLALL},
  91         {"math",        HTML_INPHRASE | HTML_NLALL | HTML_INDENT},
  92         {"mrow",        0},
  93         {"mi",          0},
  94         {"mn",          0},
  95         {"mo",          0},
  96         {"msup",        0},
  97         {"msub",        0},
  98         {"msubsup",     0},
  99         {"mfrac",       0},
 100         {"msqrt",       0},
 101         {"mfenced",     0},
 102         {"mtable",      0},
 103         {"mtr",         0},
 104         {"mtd",         0},
 105         {"munderover",  0},
 106         {"munder",      0},
 107         {"mover",       0},
 108 };
 109
 110 /* Avoid duplicate HTML id= attributes. */
 111 static  struct ohash     id_unique;
 112
 113 static  void     html_reset_internal(struct html *);
 114 static  void     print_byte(struct html *, char);
 115 static  void     print_endword(struct html *);
 116 static  void     print_indent(struct html *);
 117 static  void     print_word(struct html *, const char *);
 118
 119 static  void     print_ctag(struct html *, struct tag *);
 120 static  int      print_escape(struct html *, char);
 121 static  int      print_encode(struct html *, const char *, const char *, int);
 122 static  void     print_href(struct html *, const char *, const char *, int);
 123 static  void     print_metaf(struct html *);
 124
 125
 126 void *
 127 html_alloc(const struct manoutput *outopts)
 128 {
 129         struct html     *h;
 130
 131         h = mandoc_calloc(1, sizeof(struct html));
 132
 133         h->tag = NULL;
 134         h->style = outopts->style;
 135         if ((h->base_man1 = outopts->man) == NULL)
 136                 h->base_man2 = NULL;
 137         else if ((h->base_man2 = strchr(h->base_man1, ';')) != NULL)
 138                 *h->base_man2++ = '\0';
 139         h->base_includes = outopts->includes;
 140         if (outopts->fragment)
 141                 h->oflags |= HTML_FRAGMENT;
 142         if (outopts->toc)
 143                 h->oflags |= HTML_TOC;
 144
 145         mandoc_ohash_init(&id_unique, 4, 0);
 146
 147         return h;
 148 }
 149
 150 static void
 151 html_reset_internal(struct html *h)
 152 {
 153         struct tag      *tag;
 154         char            *cp;
 155         unsigned int     slot;
 156
 157         while ((tag = h->tag) != NULL) {
 158                 h->tag = tag->next;
 159                 free(tag);
 160         }
 161         cp = ohash_first(&id_unique, &slot);
 162         while (cp != NULL) {
 163                 free(cp);
 164                 cp = ohash_next(&id_unique, &slot);
 165         }
 166         ohash_delete(&id_unique);
 167 }
 168
 169 void
 170 html_reset(void *p)
 171 {
 172         html_reset_internal(p);
 173         mandoc_ohash_init(&id_unique, 4, 0);
 174 }
 175
 176 void
 177 html_free(void *p)
 178 {
 179         html_reset_internal(p);
 180         free(p);
 181 }
 182
 183 void
 184 print_gen_head(struct html *h)
 185 {
 186         struct tag      *t;
 187
 188         print_otag(h, TAG_META, "?", "charset", "utf-8");
 189         if (h->style != NULL) {
 190                 print_otag(h, TAG_LINK, "?h??", "rel", "stylesheet",
 191                     h->style, "type", "text/css", "media", "all");
 192                 return;
 193         }
 194
 195         /*
 196          * Print a minimal embedded style sheet.
 197          */
 198
 199         t = print_otag(h, TAG_STYLE, "");
 200         print_text(h, "table.head, table.foot { width: 100%; }");
 201         print_endline(h);
 202         print_text(h, "td.head-rtitle, td.foot-os { text-align: right; }");
 203         print_endline(h);
 204         print_text(h, "td.head-vol { text-align: center; }");
 205         print_endline(h);
 206         print_text(h, ".Nd, .Bf, .Op { display: inline; }");
 207         print_endline(h);
 208         print_text(h, ".Pa, .Ad { font-style: italic; }");
 209         print_endline(h);
 210         print_text(h, ".Ms { font-weight: bold; }");
 211         print_endline(h);
 212         print_text(h, ".Bl-diag ");
 213         print_byte(h, '>');
 214         print_text(h, " dt { font-weight: bold; }");
 215         print_endline(h);
 216         print_text(h, "code.Nm, .Fl, .Cm, .Ic, code.In, .Fd, .Fn, .Cd "
 217             "{ font-weight: bold; font-family: inherit; }");
 218         print_tagq(h, t);
 219 }
 220
 221 int
 222 html_setfont(struct html *h, enum mandoc_esc font)
 223 {
 224         switch (font) {
 225         case ESCAPE_FONTPREV:
 226                 font = h->metal;
 227                 break;
 228         case ESCAPE_FONTITALIC:
 229         case ESCAPE_FONTBOLD:
 230         case ESCAPE_FONTBI:
 231         case ESCAPE_FONTCW:
 232         case ESCAPE_FONTROMAN:
 233                 break;
 234         case ESCAPE_FONT:
 235                 font = ESCAPE_FONTROMAN;
 236                 break;
 237         default:
 238                 return 0;
 239         }
 240         h->metal = h->metac;
 241         h->metac = font;
 242         return 1;
 243 }
 244
 245 static void
 246 print_metaf(struct html *h)
 247 {
 248         if (h->metaf) {
 249                 print_tagq(h, h->metaf);
 250                 h->metaf = NULL;
 251         }
 252         switch (h->metac) {
 253         case ESCAPE_FONTITALIC:
 254                 h->metaf = print_otag(h, TAG_I, "");
 255                 break;
 256         case ESCAPE_FONTBOLD:
 257                 h->metaf = print_otag(h, TAG_B, "");
 258                 break;
 259         case ESCAPE_FONTBI:
 260                 h->metaf = print_otag(h, TAG_B, "");
 261                 print_otag(h, TAG_I, "");
 262                 break;
 263         case ESCAPE_FONTCW:
 264                 h->metaf = print_otag(h, TAG_SPAN, "c", "Li");
 265                 break;
 266         default:
 267                 break;
 268         }
 269 }
 270
 271 void
 272 html_close_paragraph(struct html *h)
 273 {
 274         struct tag      *t;
 275
 276         for (t = h->tag; t != NULL && t->closed == 0; t = t->next) {
 277                 switch(t->tag) {
 278                 case TAG_P:
 279                 case TAG_PRE:
 280                         print_tagq(h, t);
 281                         break;
 282                 case TAG_A:
 283                         print_tagq(h, t);
 284                         continue;
 285                 default:
 286                         continue;
 287                 }
 288                 break;
 289         }
 290 }
 291
 292 /*
 293  * ROFF_nf switches to no-fill mode, ROFF_fi to fill mode.
 294  * TOKEN_NONE does not switch.  The old mode is returned.
 295  */
 296 enum roff_tok
 297 html_fillmode(struct html *h, enum roff_tok want)
 298 {
 299         struct tag      *t;
 300         enum roff_tok    had;
 301
 302         for (t = h->tag; t != NULL; t = t->next)
 303                 if (t->tag == TAG_PRE)
 304                         break;
 305
 306         had = t == NULL ? ROFF_fi : ROFF_nf;
 307
 308         if (want != had) {
 309                 switch (want) {
 310                 case ROFF_fi:
 311                         print_tagq(h, t);
 312                         break;
 313                 case ROFF_nf:
 314                         html_close_paragraph(h);
 315                         print_otag(h, TAG_PRE, "");
 316                         break;
 317                 case TOKEN_NONE:
 318                         break;
 319                 default:
 320                         abort();
 321                 }
 322         }
 323         return had;
 324 }
 325
 326 char *
 327 html_make_id(const struct roff_node *n, int unique)
 328 {
 329         const struct roff_node  *nch;
 330         char                    *buf, *bufs, *cp;
 331         unsigned int             slot;
 332         int                      suffix;
 333
 334         for (nch = n->child; nch != NULL; nch = nch->next)
 335                 if (nch->type != ROFFT_TEXT)
 336                         return NULL;
 337
 338         buf = NULL;
 339         deroff(&buf, n);
 340         if (buf == NULL)
 341                 return NULL;
 342
 343         /*
 344          * In ID attributes, only use ASCII characters that are
 345          * permitted in URL-fragment strings according to the
 346          * explicit list at:
 347          * https://url.spec.whatwg.org/#url-fragment-string
 348          */
 349
 350         for (cp = buf; *cp != '\0'; cp++)
 351                 if (isalnum((unsigned char)*cp) == 0 &&
 352                     strchr("!$&'()*+,-./:;=?@_~", *cp) == NULL)
 353                         *cp = '_';
 354
 355         if (unique == 0)
 356                 return buf;
 357
 358         /* Avoid duplicate HTML id= attributes. */
 359
 360         bufs = NULL;
 361         suffix = 1;
 362         slot = ohash_qlookup(&id_unique, buf);
 363         cp = ohash_find(&id_unique, slot);
 364         if (cp != NULL) {
 365                 while (cp != NULL) {
 366                         free(bufs);
 367                         if (++suffix > 127) {
 368                                 free(buf);
 369                                 return NULL;
 370                         }
 371                         mandoc_asprintf(&bufs, "%s_%d", buf, suffix);
 372                         slot = ohash_qlookup(&id_unique, bufs);
 373                         cp = ohash_find(&id_unique, slot);
 374                 }
 375                 free(buf);
 376                 buf = bufs;
 377         }
 378         ohash_insert(&id_unique, slot, buf);
 379         return buf;
 380 }
 381
 382 static int
 383 print_escape(struct html *h, char c)
 384 {
 385
 386         switch (c) {
 387         case '<':
 388                 print_word(h, "&lt;");
 389                 break;
 390         case '>':
 391                 print_word(h, "&gt;");
 392                 break;
 393         case '&':
 394                 print_word(h, "&amp;");
 395                 break;
 396         case '"':
 397                 print_word(h, "&quot;");
 398                 break;
 399         case ASCII_NBRSP:
 400                 print_word(h, "&nbsp;");
 401                 break;
 402         case ASCII_HYPH:
 403                 print_byte(h, '-');
 404                 break;
 405         case ASCII_BREAK:
 406                 break;
 407         default:
 408                 return 0;
 409         }
 410         return 1;
 411 }
 412
 413 static int
 414 print_encode(struct html *h, const char *p, const char *pend, int norecurse)
 415 {
 416         char             numbuf[16];
 417         const char      *seq;
 418         size_t           sz;
 419         int              c, len, breakline, nospace;
 420         enum mandoc_esc  esc;
 421         static const char rejs[10] = { ' ', '\\', '<', '>', '&', '"',
 422                 ASCII_NBRSP, ASCII_HYPH, ASCII_BREAK, '\0' };
 423
 424         if (pend == NULL)
 425                 pend = strchr(p, '\0');
 426
 427         breakline = 0;
 428         nospace = 0;
 429
 430         while (p < pend) {
 431                 if (HTML_SKIPCHAR & h->flags && '\\' != *p) {
 432                         h->flags &= ~HTML_SKIPCHAR;
 433                         p++;
 434                         continue;
 435                 }
 436
 437                 for (sz = strcspn(p, rejs); sz-- && p < pend; p++)
 438                         print_byte(h, *p);
 439
 440                 if (breakline &&
 441                     (p >= pend || *p == ' ' || *p == ASCII_NBRSP)) {
 442                         print_otag(h, TAG_BR, "");
 443                         breakline = 0;
 444                         while (p < pend && (*p == ' ' || *p == ASCII_NBRSP))
 445                                 p++;
 446                         continue;
 447                 }
 448
 449                 if (p >= pend)
 450                         break;
 451
 452                 if (*p == ' ') {
 453                         print_endword(h);
 454                         p++;
 455                         continue;
 456                 }
 457
 458                 if (print_escape(h, *p++))
 459                         continue;
 460
 461                 esc = mandoc_escape(&p, &seq, &len);
 462                 switch (esc) {
 463                 case ESCAPE_FONT:
 464                 case ESCAPE_FONTPREV:
 465                 case ESCAPE_FONTBOLD:
 466                 case ESCAPE_FONTITALIC:
 467                 case ESCAPE_FONTBI:
 468                 case ESCAPE_FONTCW:
 469                 case ESCAPE_FONTROMAN:
 470                         if (0 == norecurse) {
 471                                 h->flags |= HTML_NOSPACE;
 472                                 if (html_setfont(h, esc))
 473                                         print_metaf(h);
 474                                 h->flags &= ~HTML_NOSPACE;
 475                         }
 476                         continue;
 477                 case ESCAPE_SKIPCHAR:
 478                         h->flags |= HTML_SKIPCHAR;
 479                         continue;
 480                 case ESCAPE_ERROR:
 481                         continue;
 482                 default:
 483                         break;
 484                 }
 485
 486                 if (h->flags & HTML_SKIPCHAR) {
 487                         h->flags &= ~HTML_SKIPCHAR;
 488                         continue;
 489                 }
 490
 491                 switch (esc) {
 492                 case ESCAPE_UNICODE:
 493                         /* Skip past "u" header. */
 494                         c = mchars_num2uc(seq + 1, len - 1);
 495                         break;
 496                 case ESCAPE_NUMBERED:
 497                         c = mchars_num2char(seq, len);
 498                         if (c < 0)
 499                                 continue;
 500                         break;
 501                 case ESCAPE_SPECIAL:
 502                         c = mchars_spec2cp(seq, len);
 503                         if (c <= 0)
 504                                 continue;
 505                         break;
 506                 case ESCAPE_UNDEF:
 507                         c = *seq;
 508                         break;
 509                 case ESCAPE_DEVICE:
 510                         print_word(h, "html");
 511                         continue;
 512                 case ESCAPE_BREAK:
 513                         breakline = 1;
 514                         continue;
 515                 case ESCAPE_NOSPACE:
 516                         if ('\0' == *p)
 517                                 nospace = 1;
 518                         continue;
 519                 case ESCAPE_OVERSTRIKE:
 520                         if (len == 0)
 521                                 continue;
 522                         c = seq[len - 1];
 523                         break;
 524                 default:
 525                         continue;
 526                 }
 527                 if ((c < 0x20 && c != 0x09) ||
 528                     (c > 0x7E && c < 0xA0))
 529                         c = 0xFFFD;
 530                 if (c > 0x7E) {
 531                         (void)snprintf(numbuf, sizeof(numbuf), "&#x%.4X;", c);
 532                         print_word(h, numbuf);
 533                 } else if (print_escape(h, c) == 0)
 534                         print_byte(h, c);
 535         }
 536
 537         return nospace;
 538 }
 539
 540 static void
 541 print_href(struct html *h, const char *name, const char *sec, int man)
 542 {
 543         struct stat      sb;
 544         const char      *p, *pp;
 545         char            *filename;
 546
 547         if (man) {
 548                 pp = h->base_man1;
 549                 if (h->base_man2 != NULL) {
 550                         mandoc_asprintf(&filename, "%s.%s", name, sec);
 551                         if (stat(filename, &sb) == -1)
 552                                 pp = h->base_man2;
 553                         free(filename);
 554                 }
 555         } else
 556                 pp = h->base_includes;
 557
 558         while ((p = strchr(pp, '%')) != NULL) {
 559                 print_encode(h, pp, p, 1);
 560                 if (man && p[1] == 'S') {
 561                         if (sec == NULL)
 562                                 print_byte(h, '1');
 563                         else
 564                                 print_encode(h, sec, NULL, 1);
 565                 } else if ((man && p[1] == 'N') ||
 566                     (man == 0 && p[1] == 'I'))
 567                         print_encode(h, name, NULL, 1);
 568                 else
 569                         print_encode(h, p, p + 2, 1);
 570                 pp = p + 2;
 571         }
 572         if (*pp != '\0')
 573                 print_encode(h, pp, NULL, 1);
 574 }
 575
 576 struct tag *
 577 print_otag(struct html *h, enum htmltag tag, const char *fmt, ...)
 578 {
 579         va_list          ap;
 580         struct tag      *t;
 581         const char      *attr;
 582         char            *arg1, *arg2;
 583         int              style_written, tflags;
 584
 585         tflags = htmltags[tag].flags;
 586
 587         /* Flow content is not allowed in phrasing context. */
 588
 589         if ((tflags & HTML_INPHRASE) == 0) {
 590                 for (t = h->tag; t != NULL; t = t->next) {
 591                         if (t->closed)
 592                                 continue;
 593                         assert((htmltags[t->tag].flags & HTML_TOPHRASE) == 0);
 594                         break;
 595                 }
 596         }
 597
 598         /* Push this tag onto the stack of open scopes. */
 599
 600         if ((tflags & HTML_NOSTACK) == 0) {
 601                 t = mandoc_malloc(sizeof(struct tag));
 602                 t->tag = tag;
 603                 t->next = h->tag;
 604                 t->refcnt = 0;
 605                 t->closed = 0;
 606                 h->tag = t;
 607         } else
 608                 t = NULL;
 609
 610         if (tflags & HTML_NLBEFORE)
 611                 print_endline(h);
 612         if (h->col == 0)
 613                 print_indent(h);
 614         else if ((h->flags & HTML_NOSPACE) == 0) {
 615                 if (h->flags & HTML_KEEP)
 616                         print_word(h, "&#x00A0;");
 617                 else {
 618                         if (h->flags & HTML_PREKEEP)
 619                                 h->flags |= HTML_KEEP;
 620                         print_endword(h);
 621                 }
 622         }
 623
 624         if ( ! (h->flags & HTML_NONOSPACE))
 625                 h->flags &= ~HTML_NOSPACE;
 626         else
 627                 h->flags |= HTML_NOSPACE;
 628
 629         /* Print out the tag name and attributes. */
 630
 631         print_byte(h, '<');
 632         print_word(h, htmltags[tag].name);
 633
 634         va_start(ap, fmt);
 635
 636         while (*fmt != '\0' && *fmt != 's') {
 637
 638                 /* Parse attributes and arguments. */
 639
 640                 arg1 = va_arg(ap, char *);
 641                 arg2 = NULL;
 642                 switch (*fmt++) {
 643                 case 'c':
 644                         attr = "class";
 645                         break;
 646                 case 'h':
 647                         attr = "href";
 648                         break;
 649                 case 'i':
 650                         attr = "id";
 651                         break;
 652                 case '?':
 653                         attr = arg1;
 654                         arg1 = va_arg(ap, char *);
 655                         break;
 656                 default:
 657                         abort();
 658                 }
 659                 if (*fmt == 'M')
 660                         arg2 = va_arg(ap, char *);
 661                 if (arg1 == NULL)
 662                         continue;
 663
 664                 /* Print the attributes. */
 665
 666                 print_byte(h, ' ');
 667                 print_word(h, attr);
 668                 print_byte(h, '=');
 669                 print_byte(h, '"');
 670                 switch (*fmt) {
 671                 case 'I':
 672                         print_href(h, arg1, NULL, 0);
 673                         fmt++;
 674                         break;
 675                 case 'M':
 676                         print_href(h, arg1, arg2, 1);
 677                         fmt++;
 678                         break;
 679                 case 'R':
 680                         print_byte(h, '#');
 681                         print_encode(h, arg1, NULL, 1);
 682                         fmt++;
 683                         break;
 684                 default:
 685                         print_encode(h, arg1, NULL, 1);
 686                         break;
 687                 }
 688                 print_byte(h, '"');
 689         }
 690
 691         style_written = 0;
 692         while (*fmt++ == 's') {
 693                 arg1 = va_arg(ap, char *);
 694                 arg2 = va_arg(ap, char *);
 695                 if (arg2 == NULL)
 696                         continue;
 697                 print_byte(h, ' ');
 698                 if (style_written == 0) {
 699                         print_word(h, "style=\"");
 700                         style_written = 1;
 701                 }
 702                 print_word(h, arg1);
 703                 print_byte(h, ':');
 704                 print_byte(h, ' ');
 705                 print_word(h, arg2);
 706                 print_byte(h, ';');
 707         }
 708         if (style_written)
 709                 print_byte(h, '"');
 710
 711         va_end(ap);
 712
 713         /* Accommodate for "well-formed" singleton escaping. */
 714
 715         if (htmltags[tag].flags & HTML_NOSTACK)
 716                 print_byte(h, '/');
 717
 718         print_byte(h, '>');
 719
 720         if (tflags & HTML_NLBEGIN)
 721                 print_endline(h);
 722         else
 723                 h->flags |= HTML_NOSPACE;
 724
 725         if (tflags & HTML_INDENT)
 726                 h->indent++;
 727         if (tflags & HTML_NOINDENT)
 728                 h->noindent++;
 729
 730         return t;
 731 }
 732
 733 static void
 734 print_ctag(struct html *h, struct tag *tag)
 735 {
 736         int      tflags;
 737
 738         if (tag->closed == 0) {
 739                 tag->closed = 1;
 740                 if (tag == h->metaf)
 741                         h->metaf = NULL;
 742                 if (tag == h->tblt)
 743                         h->tblt = NULL;
 744
 745                 tflags = htmltags[tag->tag].flags;
 746                 if (tflags & HTML_INDENT)
 747                         h->indent--;
 748                 if (tflags & HTML_NOINDENT)
 749                         h->noindent--;
 750                 if (tflags & HTML_NLEND)
 751                         print_endline(h);
 752                 print_indent(h);
 753                 print_byte(h, '<');
 754                 print_byte(h, '/');
 755                 print_word(h, htmltags[tag->tag].name);
 756                 print_byte(h, '>');
 757                 if (tflags & HTML_NLAFTER)
 758                         print_endline(h);
 759         }
 760         if (tag->refcnt == 0) {
 761                 h->tag = tag->next;
 762                 free(tag);
 763         }
 764 }
 765
 766 void
 767 print_gen_decls(struct html *h)
 768 {
 769         print_word(h, "<!DOCTYPE html>");
 770         print_endline(h);
 771 }
 772
 773 void
 774 print_gen_comment(struct html *h, struct roff_node *n)
 775 {
 776         int      wantblank;
 777
 778         print_word(h, "<!-- This is an automatically generated file."
 779             "  Do not edit.");
 780         h->indent = 1;
 781         wantblank = 0;
 782         while (n != NULL && n->type == ROFFT_COMMENT) {
 783                 if (strstr(n->string, "-->") == NULL &&
 784                     (wantblank || *n->string != '\0')) {
 785                         print_endline(h);
 786                         print_indent(h);
 787                         print_word(h, n->string);
 788                         wantblank = *n->string != '\0';
 789                 }
 790                 n = n->next;
 791         }
 792         if (wantblank)
 793                 print_endline(h);
 794         print_word(h, " -->");
 795         print_endline(h);
 796         h->indent = 0;
 797 }
 798
 799 void
 800 print_text(struct html *h, const char *word)
 801 {
 802         if (h->col && (h->flags & HTML_NOSPACE) == 0) {
 803                 if ( ! (HTML_KEEP & h->flags)) {
 804                         if (HTML_PREKEEP & h->flags)
 805                                 h->flags |= HTML_KEEP;
 806                         print_endword(h);
 807                 } else
 808                         print_word(h, "&#x00A0;");
 809         }
 810
 811         assert(h->metaf == NULL);
 812         print_metaf(h);
 813         print_indent(h);
 814         if ( ! print_encode(h, word, NULL, 0)) {
 815                 if ( ! (h->flags & HTML_NONOSPACE))
 816                         h->flags &= ~HTML_NOSPACE;
 817                 h->flags &= ~HTML_NONEWLINE;
 818         } else
 819                 h->flags |= HTML_NOSPACE | HTML_NONEWLINE;
 820
 821         if (h->metaf != NULL) {
 822                 print_tagq(h, h->metaf);
 823                 h->metaf = NULL;
 824         }
 825
 826         h->flags &= ~HTML_IGNDELIM;
 827 }
 828
 829 void
 830 print_tagq(struct html *h, const struct tag *until)
 831 {
 832         struct tag      *this, *next;
 833
 834         for (this = h->tag; this != NULL; this = next) {
 835                 next = this == until ? NULL : this->next;
 836                 print_ctag(h, this);
 837         }
 838 }
 839
 840 /*
 841  * Close out all open elements up to but excluding suntil.
 842  * Note that a paragraph just inside stays open together with it
 843  * because paragraphs include subsequent phrasing content.
 844  */
 845 void
 846 print_stagq(struct html *h, const struct tag *suntil)
 847 {
 848         struct tag      *this, *next;
 849
 850         for (this = h->tag; this != NULL; this = next) {
 851                 next = this->next;
 852                 if (this == suntil || (next == suntil &&
 853                     (this->tag == TAG_P || this->tag == TAG_PRE)))
 854                         break;
 855                 print_ctag(h, this);
 856         }
 857 }
 858
 859
 860 /***********************************************************************
 861  * Low level output functions.
 862  * They implement line breaking using a short static buffer.
 863  ***********************************************************************/
 864
 865 /*
 866  * Buffer one HTML output byte.
 867  * If the buffer is full, flush and deactivate it and start a new line.
 868  * If the buffer is inactive, print directly.
 869  */
 870 static void
 871 print_byte(struct html *h, char c)
 872 {
 873         if ((h->flags & HTML_BUFFER) == 0) {
 874                 putchar(c);
 875                 h->col++;
 876                 return;
 877         }
 878
 879         if (h->col + h->bufcol < sizeof(h->buf)) {
 880                 h->buf[h->bufcol++] = c;
 881                 return;
 882         }
 883
 884         putchar('\n');
 885         h->col = 0;
 886         print_indent(h);
 887         putchar(' ');
 888         putchar(' ');
 889         fwrite(h->buf, h->bufcol, 1, stdout);
 890         putchar(c);
 891         h->col = (h->indent + 1) * 2 + h->bufcol + 1;
 892         h->bufcol = 0;
 893         h->flags &= ~HTML_BUFFER;
 894 }
 895
 896 /*
 897  * If something was printed on the current output line, end it.
 898  * Not to be called right after print_indent().
 899  */
 900 void
 901 print_endline(struct html *h)
 902 {
 903         if (h->col == 0)
 904                 return;
 905
 906         if (h->bufcol) {
 907                 putchar(' ');
 908                 fwrite(h->buf, h->bufcol, 1, stdout);
 909                 h->bufcol = 0;
 910         }
 911         putchar('\n');
 912         h->col = 0;
 913         h->flags |= HTML_NOSPACE;
 914         h->flags &= ~HTML_BUFFER;
 915 }
 916
 917 /*
 918  * Flush the HTML output buffer.
 919  * If it is inactive, activate it.
 920  */
 921 static void
 922 print_endword(struct html *h)
 923 {
 924         if (h->noindent) {
 925                 print_byte(h, ' ');
 926                 return;
 927         }
 928
 929         if ((h->flags & HTML_BUFFER) == 0) {
 930                 h->col++;
 931                 h->flags |= HTML_BUFFER;
 932         } else if (h->bufcol) {
 933                 putchar(' ');
 934                 fwrite(h->buf, h->bufcol, 1, stdout);
 935                 h->col += h->bufcol + 1;
 936         }
 937         h->bufcol = 0;
 938 }
 939
 940 /*
 941  * If at the beginning of a new output line,
 942  * perform indentation and mark the line as containing output.
 943  * Make sure to really produce some output right afterwards,
 944  * but do not use print_otag() for producing it.
 945  */
 946 static void
 947 print_indent(struct html *h)
 948 {
 949         size_t   i;
 950
 951         if (h->col)
 952                 return;
 953
 954         if (h->noindent == 0) {
 955                 h->col = h->indent * 2;
 956                 for (i = 0; i < h->col; i++)
 957                         putchar(' ');
 958         }
 959         h->flags &= ~HTML_NOSPACE;
 960 }
 961
 962 /*
 963  * Print or buffer some characters
 964  * depending on the current HTML output buffer state.
 965  */
 966 static void
 967 print_word(struct html *h, const char *cp)
 968 {
 969         while (*cp != '\0')
 970                 print_byte(h, *cp++);
 971 }