src/doc.c

   1 /* Record indices of function doc strings stored in a file.
   2
   3 Copyright (C) 1985-1986, 1993-1995, 1997-2014 Free Software Foundation, Inc.
   4
   5 This file is part of GNU Emacs.
   6
   7 GNU Emacs 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 3 of the License, or
  10 (at your option) any later version.
  11
  12 GNU Emacs 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 GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20
  21 #include <config.h>
  22
  23 #include <errno.h>
  24 #include <sys/types.h>
  25 #include <sys/file.h>   /* Must be after sys/types.h for USG.  */
  26 #include <fcntl.h>
  27 #include <unistd.h>
  28
  29 #include <c-ctype.h>
  30
  31 #include "lisp.h"
  32 #include "character.h"
  33 #include "buffer.h"
  34 #include "keyboard.h"
  35 #include "keymap.h"
  36
  37 Lisp_Object Qfunction_documentation;
  38
  39 /* Buffer used for reading from documentation file.  */
  40 static char *get_doc_string_buffer;
  41 static ptrdiff_t get_doc_string_buffer_size;
  42
  43 static unsigned char *read_bytecode_pointer;
  44
  45 static char const sibling_etc[] = "../etc/";
  46
  47 /* `readchar' in lread.c calls back here to fetch the next byte.
  48    If UNREADFLAG is 1, we unread a byte.  */
  49
  50 int
  51 read_bytecode_char (bool unreadflag)
  52 {
  53   if (unreadflag)
  54     {
  55       read_bytecode_pointer--;
  56       return 0;
  57     }
  58   return *read_bytecode_pointer++;
  59 }
  60
  61 /* Extract a doc string from a file.  FILEPOS says where to get it.
  62    If it is an integer, use that position in the standard DOC file.
  63    If it is (FILE . INTEGER), use FILE as the file name
  64    and INTEGER as the position in that file.
  65    But if INTEGER is negative, make it positive.
  66    (A negative integer is used for user variables, so we can distinguish
  67    them without actually fetching the doc string.)
  68
  69    If the location does not point to the beginning of a docstring
  70    (e.g. because the file has been modified and the location is stale),
  71    return nil.
  72
  73    If UNIBYTE, always make a unibyte string.
  74
  75    If DEFINITION, assume this is for reading
  76    a dynamic function definition; convert the bytestring
  77    and the constants vector with appropriate byte handling,
  78    and return a cons cell.  */
  79
  80 Lisp_Object
  81 get_doc_string (Lisp_Object filepos, bool unibyte, bool definition)
  82 {
  83   char *from, *to, *name, *p, *p1;
  84   int fd;
  85   int offset;
  86   EMACS_INT position;
  87   Lisp_Object file, tem, pos;
  88   ptrdiff_t count;
  89   USE_SAFE_ALLOCA;
  90
  91   if (INTEGERP (filepos))
  92     {
  93       file = Vdoc_file_name;
  94       pos = filepos;
  95     }
  96   else if (CONSP (filepos))
  97     {
  98       file = XCAR (filepos);
  99       pos = XCDR (filepos);
 100     }
 101   else
 102     return Qnil;
 103
 104   position = eabs (XINT (pos));
 105
 106   if (!STRINGP (Vdoc_directory))
 107     return Qnil;
 108
 109   if (!STRINGP (file))
 110     return Qnil;
 111
 112   /* Put the file name in NAME as a C string.
 113      If it is relative, combine it with Vdoc_directory.  */
 114
 115   tem = Ffile_name_absolute_p (file);
 116   file = ENCODE_FILE (file);
 117   Lisp_Object docdir
 118     = NILP (tem) ? ENCODE_FILE (Vdoc_directory) : empty_unibyte_string;
 119   ptrdiff_t docdir_sizemax = SBYTES (docdir) + 1;
 120 #ifndef CANNOT_DUMP
 121   docdir_sizemax = max (docdir_sizemax, sizeof sibling_etc);
 122 #endif
 123   name = SAFE_ALLOCA (docdir_sizemax + SBYTES (file));
 124   lispstpcpy (lispstpcpy (name, docdir), file);
 125
 126   fd = emacs_open (name, O_RDONLY, 0);
 127   if (fd < 0)
 128     {
 129 #ifndef CANNOT_DUMP
 130       if (!NILP (Vpurify_flag))
 131         {
 132           /* Preparing to dump; DOC file is probably not installed.
 133              So check in ../etc.  */
 134           lispstpcpy (stpcpy (name, sibling_etc), file);
 135
 136           fd = emacs_open (name, O_RDONLY, 0);
 137         }
 138 #endif
 139       if (fd < 0)
 140         {
 141           SAFE_FREE ();
 142           AUTO_STRING (cannot_open, "Cannot open doc string file \"");
 143           AUTO_STRING (quote_nl, "\"\n");
 144           return concat3 (cannot_open, file, quote_nl);
 145         }
 146     }
 147   count = SPECPDL_INDEX ();
 148   record_unwind_protect_int (close_file_unwind, fd);
 149
 150   /* Seek only to beginning of disk block.  */
 151   /* Make sure we read at least 1024 bytes before `position'
 152      so we can check the leading text for consistency.  */
 153   offset = min (position, max (1024, position % (8 * 1024)));
 154   if (TYPE_MAXIMUM (off_t) < position
 155       || lseek (fd, position - offset, 0) < 0)
 156     error ("Position %"pI"d out of range in doc string file \"%s\"",
 157            position, name);
 158
 159   /* Read the doc string into get_doc_string_buffer.
 160      P points beyond the data just read.  */
 161
 162   p = get_doc_string_buffer;
 163   while (1)
 164     {
 165       ptrdiff_t space_left = (get_doc_string_buffer_size - 1
 166                               - (p - get_doc_string_buffer));
 167       int nread;
 168
 169       /* Allocate or grow the buffer if we need to.  */
 170       if (space_left <= 0)
 171         {
 172           ptrdiff_t in_buffer = p - get_doc_string_buffer;
 173           get_doc_string_buffer
 174             = xpalloc (get_doc_string_buffer, &get_doc_string_buffer_size,
 175                        16 * 1024, -1, 1);
 176           p = get_doc_string_buffer + in_buffer;
 177           space_left = (get_doc_string_buffer_size - 1
 178                         - (p - get_doc_string_buffer));
 179         }
 180
 181       /* Read a disk block at a time.
 182          If we read the same block last time, maybe skip this?  */
 183       if (space_left > 1024 * 8)
 184         space_left = 1024 * 8;
 185       nread = emacs_read (fd, p, space_left);
 186       if (nread < 0)
 187         report_file_error ("Read error on documentation file", file);
 188       p[nread] = 0;
 189       if (!nread)
 190         break;
 191       if (p == get_doc_string_buffer)
 192         p1 = strchr (p + offset, '\037');
 193       else
 194         p1 = strchr (p, '\037');
 195       if (p1)
 196         {
 197           *p1 = 0;
 198           p = p1;
 199           break;
 200         }
 201       p += nread;
 202     }
 203   unbind_to (count, Qnil);
 204   SAFE_FREE ();
 205
 206   /* Sanity checking.  */
 207   if (CONSP (filepos))
 208     {
 209       int test = 1;
 210       /* A dynamic docstring should be either at the very beginning of a "#@
 211          comment" or right after a dynamic docstring delimiter (in case we
 212          pack several such docstrings within the same comment).  */
 213       if (get_doc_string_buffer[offset - test] != '\037')
 214         {
 215           if (get_doc_string_buffer[offset - test++] != ' ')
 216             return Qnil;
 217           while (get_doc_string_buffer[offset - test] >= '0'
 218                  && get_doc_string_buffer[offset - test] <= '9')
 219             test++;
 220           if (get_doc_string_buffer[offset - test++] != '@'
 221               || get_doc_string_buffer[offset - test] != '#')
 222             return Qnil;
 223         }
 224     }
 225   else
 226     {
 227       int test = 1;
 228       if (get_doc_string_buffer[offset - test++] != '\n')
 229         return Qnil;
 230       while (get_doc_string_buffer[offset - test] > ' ')
 231         test++;
 232       if (get_doc_string_buffer[offset - test] != '\037')
 233         return Qnil;
 234     }
 235
 236   /* Scan the text and perform quoting with ^A (char code 1).
 237      ^A^A becomes ^A, ^A0 becomes a null char, and ^A_ becomes a ^_.  */
 238   from = get_doc_string_buffer + offset;
 239   to = get_doc_string_buffer + offset;
 240   while (from != p)
 241     {
 242       if (*from == 1)
 243         {
 244           int c;
 245
 246           from++;
 247           c = *from++;
 248           if (c == 1)
 249             *to++ = c;
 250           else if (c == '0')
 251             *to++ = 0;
 252           else if (c == '_')
 253             *to++ = 037;
 254           else
 255             {
 256               unsigned char uc = c;
 257               error ("\
 258 Invalid data in documentation file -- %c followed by code %03o",
 259                      1, uc);
 260             }
 261         }
 262       else
 263         *to++ = *from++;
 264     }
 265
 266   /* If DEFINITION, read from this buffer
 267      the same way we would read bytes from a file.  */
 268   if (definition)
 269     {
 270       read_bytecode_pointer = (unsigned char *) get_doc_string_buffer + offset;
 271       return Fread (Qlambda);
 272     }
 273
 274   if (unibyte)
 275     return make_unibyte_string (get_doc_string_buffer + offset,
 276                                 to - (get_doc_string_buffer + offset));
 277   else
 278     {
 279       /* The data determines whether the string is multibyte.  */
 280       ptrdiff_t nchars
 281         = multibyte_chars_in_text (((unsigned char *) get_doc_string_buffer
 282                                     + offset),
 283                                    to - (get_doc_string_buffer + offset));
 284       return make_string_from_bytes (get_doc_string_buffer + offset,
 285                                      nchars,
 286                                      to - (get_doc_string_buffer + offset));
 287     }
 288 }
 289
 290 /* Get a string from position FILEPOS and pass it through the Lisp reader.
 291    We use this for fetching the bytecode string and constants vector
 292    of a compiled function from the .elc file.  */
 293
 294 Lisp_Object
 295 read_doc_string (Lisp_Object filepos)
 296 {
 297   return get_doc_string (filepos, 0, 1);
 298 }
 299
 300 static bool
 301 reread_doc_file (Lisp_Object file)
 302 {
 303 #if 0
 304   Lisp_Object reply, prompt[3];
 305   struct gcpro gcpro1;
 306   GCPRO1 (file);
 307   prompt[0] = build_string ("File ");
 308   prompt[1] = NILP (file) ? Vdoc_file_name : file;
 309   prompt[2] = build_string (" is out of sync.  Reload? ");
 310   reply = Fy_or_n_p (Fconcat (3, prompt));
 311   UNGCPRO;
 312   if (NILP (reply))
 313     return 0;
 314 #endif
 315
 316   if (NILP (file))
 317     Fsnarf_documentation (Vdoc_file_name);
 318   else
 319     Fload (file, Qt, Qt, Qt, Qnil);
 320
 321   return 1;
 322 }
 323
 324 DEFUN ("documentation", Fdocumentation, Sdocumentation, 1, 2, 0,
 325        doc: /* Return the documentation string of FUNCTION.
 326 Unless a non-nil second argument RAW is given, the
 327 string is passed through `substitute-command-keys'.  */)
 328   (Lisp_Object function, Lisp_Object raw)
 329 {
 330   Lisp_Object fun;
 331   Lisp_Object funcar;
 332   Lisp_Object doc;
 333   bool try_reload = 1;
 334
 335  documentation:
 336
 337   doc = Qnil;
 338
 339   if (SYMBOLP (function))
 340     {
 341       Lisp_Object tem = Fget (function, Qfunction_documentation);
 342       if (!NILP (tem))
 343         return Fdocumentation_property (function, Qfunction_documentation,
 344                                         raw);
 345     }
 346
 347   fun = Findirect_function (function, Qnil);
 348   if (CONSP (fun) && EQ (XCAR (fun), Qmacro))
 349     fun = XCDR (fun);
 350   if (SUBRP (fun))
 351     {
 352       if (XSUBR (fun)->doc == 0)
 353         return Qnil;
 354       /* FIXME: This is not portable, as it assumes that string
 355          pointers have the top bit clear.  */
 356       else if ((intptr_t) XSUBR (fun)->doc >= 0)
 357         doc = build_string (XSUBR (fun)->doc);
 358       else
 359         doc = make_number ((intptr_t) XSUBR (fun)->doc);
 360     }
 361   else if (COMPILEDP (fun))
 362     {
 363       if ((ASIZE (fun) & PSEUDOVECTOR_SIZE_MASK) <= COMPILED_DOC_STRING)
 364         return Qnil;
 365       else
 366         {
 367           Lisp_Object tem = AREF (fun, COMPILED_DOC_STRING);
 368           if (STRINGP (tem))
 369             doc = tem;
 370           else if (NATNUMP (tem) || CONSP (tem))
 371             doc = tem;
 372           else
 373             return Qnil;
 374         }
 375     }
 376   else if (STRINGP (fun) || VECTORP (fun))
 377     {
 378       return build_string ("Keyboard macro.");
 379     }
 380   else if (CONSP (fun))
 381     {
 382       funcar = XCAR (fun);
 383       if (!SYMBOLP (funcar))
 384         xsignal1 (Qinvalid_function, fun);
 385       else if (EQ (funcar, Qkeymap))
 386         return build_string ("Prefix command (definition is a keymap associating keystrokes with commands).");
 387       else if (EQ (funcar, Qlambda)
 388                || (EQ (funcar, Qclosure) && (fun = XCDR (fun), 1))
 389                || EQ (funcar, Qautoload))
 390         {
 391           Lisp_Object tem1 = Fcdr (Fcdr (fun));
 392           Lisp_Object tem = Fcar (tem1);
 393           if (STRINGP (tem))
 394             doc = tem;
 395           /* Handle a doc reference--but these never come last
 396              in the function body, so reject them if they are last.  */
 397           else if ((NATNUMP (tem) || (CONSP (tem) && INTEGERP (XCDR (tem))))
 398                    && !NILP (XCDR (tem1)))
 399             doc = tem;
 400           else
 401             return Qnil;
 402         }
 403       else
 404         goto oops;
 405     }
 406   else
 407     {
 408     oops:
 409       xsignal1 (Qinvalid_function, fun);
 410     }
 411
 412   /* If DOC is 0, it's typically because of a dumped file missing
 413      from the DOC file (bug in src/Makefile.in).  */
 414   if (EQ (doc, make_number (0)))
 415     doc = Qnil;
 416   if (INTEGERP (doc) || CONSP (doc))
 417     {
 418       Lisp_Object tem;
 419       tem = get_doc_string (doc, 0, 0);
 420       if (NILP (tem) && try_reload)
 421         {
 422           /* The file is newer, we need to reset the pointers.  */
 423           struct gcpro gcpro1, gcpro2;
 424           GCPRO2 (function, raw);
 425           try_reload = reread_doc_file (Fcar_safe (doc));
 426           UNGCPRO;
 427           if (try_reload)
 428             {
 429               try_reload = 0;
 430               goto documentation;
 431             }
 432         }
 433       else
 434         doc = tem;
 435     }
 436
 437   if (NILP (raw))
 438     doc = Fsubstitute_command_keys (doc);
 439   return doc;
 440 }
 441
 442 DEFUN ("documentation-property", Fdocumentation_property,
 443        Sdocumentation_property, 2, 3, 0,
 444        doc: /* Return the documentation string that is SYMBOL's PROP property.
 445 Third argument RAW omitted or nil means pass the result through
 446 `substitute-command-keys' if it is a string.
 447
 448 This differs from `get' in that it can refer to strings stored in the
 449 `etc/DOC' file; and that it evaluates documentation properties that
 450 aren't strings.  */)
 451   (Lisp_Object symbol, Lisp_Object prop, Lisp_Object raw)
 452 {
 453   bool try_reload = 1;
 454   Lisp_Object tem;
 455
 456  documentation_property:
 457
 458   tem = Fget (symbol, prop);
 459   if (EQ (tem, make_number (0)))
 460     tem = Qnil;
 461   if (INTEGERP (tem) || (CONSP (tem) && INTEGERP (XCDR (tem))))
 462     {
 463       Lisp_Object doc = tem;
 464       tem = get_doc_string (tem, 0, 0);
 465       if (NILP (tem) && try_reload)
 466         {
 467           /* The file is newer, we need to reset the pointers.  */
 468           struct gcpro gcpro1, gcpro2, gcpro3;
 469           GCPRO3 (symbol, prop, raw);
 470           try_reload = reread_doc_file (Fcar_safe (doc));
 471           UNGCPRO;
 472           if (try_reload)
 473             {
 474               try_reload = 0;
 475               goto documentation_property;
 476             }
 477         }
 478     }
 479   else if (!STRINGP (tem))
 480     /* Feval protects its argument.  */
 481     tem = Feval (tem, Qnil);
 482
 483   if (NILP (raw) && STRINGP (tem))
 484     tem = Fsubstitute_command_keys (tem);
 485   return tem;
 486 }
 487 \f
 488 /* Scanning the DOC files and placing docstring offsets into functions.  */
 489
 490 static void
 491 store_function_docstring (Lisp_Object obj, ptrdiff_t offset)
 492 {
 493   /* Don't use indirect_function here, or defaliases will apply their
 494      docstrings to the base functions (Bug#2603).  */
 495   Lisp_Object fun = SYMBOLP (obj) ? XSYMBOL (obj)->function : obj;
 496
 497   /* The type determines where the docstring is stored.  */
 498
 499   /* Lisp_Subrs have a slot for it.  */
 500   if (SUBRP (fun))
 501     {
 502       intptr_t negative_offset = - offset;
 503       XSUBR (fun)->doc = (char *) negative_offset;
 504     }
 505
 506   /* If it's a lisp form, stick it in the form.  */
 507   else if (CONSP (fun))
 508     {
 509       Lisp_Object tem;
 510
 511       tem = XCAR (fun);
 512       if (EQ (tem, Qlambda) || EQ (tem, Qautoload)
 513           || (EQ (tem, Qclosure) && (fun = XCDR (fun), 1)))
 514         {
 515           tem = Fcdr (Fcdr (fun));
 516           if (CONSP (tem) && INTEGERP (XCAR (tem)))
 517             /* FIXME: This modifies typically pure hash-cons'd data, so its
 518                correctness is quite delicate.  */
 519             XSETCAR (tem, make_number (offset));
 520         }
 521       else if (EQ (tem, Qmacro))
 522         store_function_docstring (XCDR (fun), offset);
 523     }
 524
 525   /* Bytecode objects sometimes have slots for it.  */
 526   else if (COMPILEDP (fun))
 527     {
 528       /* This bytecode object must have a slot for the
 529          docstring, since we've found a docstring for it.  */
 530       if ((ASIZE (fun) & PSEUDOVECTOR_SIZE_MASK) > COMPILED_DOC_STRING)
 531         ASET (fun, COMPILED_DOC_STRING, make_number (offset));
 532       else
 533         message ("No docstring slot for %s",
 534                  SYMBOLP (obj) ? SSDATA (SYMBOL_NAME (obj)) : "<anonymous>");
 535     }
 536 }
 537
 538
 539 DEFUN ("Snarf-documentation", Fsnarf_documentation, Ssnarf_documentation,
 540        1, 1, 0,
 541        doc: /* Used during Emacs initialization to scan the `etc/DOC...' file.
 542 This searches the `etc/DOC...' file for doc strings and
 543 records them in function and variable definitions.
 544 The function takes one argument, FILENAME, a string;
 545 it specifies the file name (without a directory) of the DOC file.
 546 That file is found in `../etc' now; later, when the dumped Emacs is run,
 547 the same file name is found in the `doc-directory'.  */)
 548   (Lisp_Object filename)
 549 {
 550   int fd;
 551   char buf[1024 + 1];
 552   int filled;
 553   EMACS_INT pos;
 554   Lisp_Object sym;
 555   char *p, *name;
 556   bool skip_file = 0;
 557   ptrdiff_t count;
 558   char const *dirname;
 559   ptrdiff_t dirlen;
 560   /* Preloaded defcustoms using custom-initialize-delay are added to
 561      this list, but kept unbound.  See http://debbugs.gnu.org/11565  */
 562   Lisp_Object delayed_init =
 563     find_symbol_value (intern ("custom-delayed-init-variables"));
 564
 565   if (EQ (delayed_init, Qunbound)) delayed_init = Qnil;
 566
 567   CHECK_STRING (filename);
 568
 569   if
 570 #ifndef CANNOT_DUMP
 571     (!NILP (Vpurify_flag))
 572 #else /* CANNOT_DUMP */
 573       (0)
 574 #endif /* CANNOT_DUMP */
 575     {
 576       dirname = sibling_etc;
 577       dirlen = sizeof sibling_etc - 1;
 578     }
 579   else
 580     {
 581       CHECK_STRING (Vdoc_directory);
 582       dirname = SSDATA (Vdoc_directory);
 583       dirlen = SBYTES (Vdoc_directory);
 584     }
 585
 586   count = SPECPDL_INDEX ();
 587   USE_SAFE_ALLOCA;
 588   name = SAFE_ALLOCA (dirlen + SBYTES (filename) + 1);
 589   lispstpcpy (stpcpy (name, dirname), filename);        /*** Add this line ***/
 590
 591   /* Vbuild_files is nil when temacs is run, and non-nil after that.  */
 592   if (NILP (Vbuild_files))
 593     {
 594       static char const *const buildobj[] =
 595         {
 596           #include "buildobj.h"
 597         };
 598       int i = ARRAYELTS (buildobj);
 599       while (0 <= --i)
 600         Vbuild_files = Fcons (build_string (buildobj[i]), Vbuild_files);
 601       Vbuild_files = Fpurecopy (Vbuild_files);
 602     }
 603
 604   fd = emacs_open (name, O_RDONLY, 0);
 605   if (fd < 0)
 606     {
 607       int open_errno = errno;
 608       report_file_errno ("Opening doc string file", build_string (name),
 609                          open_errno);
 610     }
 611   record_unwind_protect_int (close_file_unwind, fd);
 612   Vdoc_file_name = filename;
 613   filled = 0;
 614   pos = 0;
 615   while (1)
 616     {
 617       register char *end;
 618       if (filled < 512)
 619         filled += emacs_read (fd, &buf[filled], sizeof buf - 1 - filled);
 620       if (!filled)
 621         break;
 622
 623       buf[filled] = 0;
 624       end = buf + (filled < 512 ? filled : filled - 128);
 625       p = memchr (buf, '\037', end - buf);
 626       /* p points to ^_Ffunctionname\n or ^_Vvarname\n or ^_Sfilename\n.  */
 627       if (p)
 628         {
 629           end = strchr (p, '\n');
 630
 631           /* See if this is a file name, and if it is a file in build-files.  */
 632           if (p[1] == 'S')
 633             {
 634               skip_file = 0;
 635               if (end - p > 4 && end[-2] == '.'
 636                   && (end[-1] == 'o' || end[-1] == 'c'))
 637                 {
 638                   ptrdiff_t len = end - p - 2;
 639                   char *fromfile = SAFE_ALLOCA (len + 1);
 640                   memcpy (fromfile, &p[2], len);
 641                   fromfile[len] = 0;
 642                   if (fromfile[len-1] == 'c')
 643                     fromfile[len-1] = 'o';
 644
 645                   skip_file = NILP (Fmember (build_string (fromfile),
 646                                              Vbuild_files));
 647                 }
 648             }
 649
 650           sym = oblookup (Vobarray, p + 2,
 651                           multibyte_chars_in_text ((unsigned char *) p + 2,
 652                                                    end - p - 2),
 653                           end - p - 2);
 654           /* Check skip_file so that when a function is defined several
 655              times in different files (typically, once in xterm, once in
 656              w32term, ...), we only pay attention to the one that
 657              matters.  */
 658           if (! skip_file && SYMBOLP (sym))
 659             {
 660               /* Attach a docstring to a variable?  */
 661               if (p[1] == 'V')
 662                 {
 663                   /* Install file-position as variable-documentation property
 664                      and make it negative for a user-variable
 665                      (doc starts with a `*').  */
 666                   if (!NILP (Fboundp (sym))
 667                       || !NILP (Fmemq (sym, delayed_init)))
 668                     Fput (sym, Qvariable_documentation,
 669                           make_number ((pos + end + 1 - buf)
 670                                        * (end[1] == '*' ? -1 : 1)));
 671                 }
 672
 673               /* Attach a docstring to a function?  */
 674               else if (p[1] == 'F')
 675                 {
 676                   if (!NILP (Ffboundp (sym)))
 677                     store_function_docstring (sym, pos + end + 1 - buf);
 678                 }
 679               else if (p[1] == 'S')
 680                 ; /* Just a source file name boundary marker.  Ignore it.  */
 681
 682               else
 683                 error ("DOC file invalid at position %"pI"d", pos);
 684             }
 685         }
 686       pos += end - buf;
 687       filled -= end - buf;
 688       memmove (buf, end, filled);
 689     }
 690
 691   SAFE_FREE ();
 692   return unbind_to (count, Qnil);
 693 }
 694 \f
 695 DEFUN ("substitute-command-keys", Fsubstitute_command_keys,
 696        Ssubstitute_command_keys, 1, 1, 0,
 697        doc: /* Substitute key descriptions for command names in STRING.
 698 Each substring of the form \\=\\[COMMAND] is replaced by either a
 699 keystroke sequence that invokes COMMAND, or "M-x COMMAND" if COMMAND
 700 is not on any keys.
 701
 702 Each substring of the form \\=\\{MAPVAR} is replaced by a summary of
 703 the value of MAPVAR as a keymap.  This summary is similar to the one
 704 produced by `describe-bindings'.  The summary ends in two newlines
 705 \(used by the helper function `help-make-xrefs' to find the end of the
 706 summary).
 707
 708 Each substring of the form \\=\\<MAPVAR> specifies the use of MAPVAR
 709 as the keymap for future \\=\\[COMMAND] substrings.
 710 \\=\\= quotes the following character and is discarded;
 711 thus, \\=\\=\\=\\= puts \\=\\= into the output, and \\=\\=\\=\\[ puts \\=\\[ into the output.
 712
 713 Return the original STRING if no substitutions are made.
 714 Otherwise, return a new string.  */)
 715   (Lisp_Object string)
 716 {
 717   char *buf;
 718   bool changed = 0;
 719   unsigned char *strp;
 720   char *bufp;
 721   ptrdiff_t idx;
 722   ptrdiff_t bsize;
 723   Lisp_Object tem;
 724   Lisp_Object keymap;
 725   unsigned char *start;
 726   ptrdiff_t length, length_byte;
 727   Lisp_Object name;
 728   struct gcpro gcpro1, gcpro2, gcpro3, gcpro4;
 729   bool multibyte;
 730   ptrdiff_t nchars;
 731
 732   if (NILP (string))
 733     return Qnil;
 734
 735   CHECK_STRING (string);
 736   tem = Qnil;
 737   keymap = Qnil;
 738   name = Qnil;
 739   GCPRO4 (string, tem, keymap, name);
 740
 741   multibyte = STRING_MULTIBYTE (string);
 742   nchars = 0;
 743
 744   /* KEYMAP is either nil (which means search all the active keymaps)
 745      or a specified local map (which means search just that and the
 746      global map).  If non-nil, it might come from Voverriding_local_map,
 747      or from a \\<mapname> construct in STRING itself..  */
 748   keymap = Voverriding_local_map;
 749
 750   bsize = SBYTES (string);
 751   bufp = buf = xmalloc (bsize);
 752
 753   strp = SDATA (string);
 754   while (strp < SDATA (string) + SBYTES (string))
 755     {
 756       if (strp[0] == '\\' && strp[1] == '=')
 757         {
 758           /* \= quotes the next character;
 759              thus, to put in \[ without its special meaning, use \=\[.  */
 760           changed = 1;
 761           strp += 2;
 762           if (multibyte)
 763             {
 764               int len;
 765
 766               STRING_CHAR_AND_LENGTH (strp, len);
 767               if (len == 1)
 768                 *bufp = *strp;
 769               else
 770                 memcpy (bufp, strp, len);
 771               strp += len;
 772               bufp += len;
 773               nchars++;
 774             }
 775           else
 776             *bufp++ = *strp++, nchars++;
 777         }
 778       else if (strp[0] == '\\' && strp[1] == '[')
 779         {
 780           ptrdiff_t start_idx;
 781           bool follow_remap = 1;
 782
 783           changed = 1;
 784           strp += 2;            /* skip \[ */
 785           start = strp;
 786           start_idx = start - SDATA (string);
 787
 788           while ((strp - SDATA (string)
 789                   < SBYTES (string))
 790                  && *strp != ']')
 791             strp++;
 792           length_byte = strp - start;
 793
 794           strp++;               /* skip ] */
 795
 796           /* Save STRP in IDX.  */
 797           idx = strp - SDATA (string);
 798           name = Fintern (make_string ((char *) start, length_byte), Qnil);
 799
 800         do_remap:
 801           tem = Fwhere_is_internal (name, keymap, Qt, Qnil, Qnil);
 802
 803           if (VECTORP (tem) && ASIZE (tem) > 1
 804               && EQ (AREF (tem, 0), Qremap) && SYMBOLP (AREF (tem, 1))
 805               && follow_remap)
 806             {
 807               name = AREF (tem, 1);
 808               follow_remap = 0;
 809               goto do_remap;
 810             }
 811
 812           /* Note the Fwhere_is_internal can GC, so we have to take
 813              relocation of string contents into account.  */
 814           strp = SDATA (string) + idx;
 815           start = SDATA (string) + start_idx;
 816
 817           if (NILP (tem))       /* but not on any keys */
 818             {
 819               ptrdiff_t offset = bufp - buf;
 820               if (STRING_BYTES_BOUND - 4 < bsize)
 821                 string_overflow ();
 822               buf = xrealloc (buf, bsize += 4);
 823               bufp = buf + offset;
 824               memcpy (bufp, "M-x ", 4);
 825               bufp += 4;
 826               nchars += 4;
 827               if (multibyte)
 828                 length = multibyte_chars_in_text (start, length_byte);
 829               else
 830                 length = length_byte;
 831               goto subst;
 832             }
 833           else
 834             {                   /* function is on a key */
 835               tem = Fkey_description (tem, Qnil);
 836               goto subst_string;
 837             }
 838         }
 839       /* \{foo} is replaced with a summary of the keymap (symbol-value foo).
 840          \<foo> just sets the keymap used for \[cmd].  */
 841       else if (strp[0] == '\\' && (strp[1] == '{' || strp[1] == '<'))
 842         {
 843           struct buffer *oldbuf;
 844           ptrdiff_t start_idx;
 845           /* This is for computing the SHADOWS arg for describe_map_tree.  */
 846           Lisp_Object active_maps = Fcurrent_active_maps (Qnil, Qnil);
 847           Lisp_Object earlier_maps;
 848           ptrdiff_t count = SPECPDL_INDEX ();
 849
 850           changed = 1;
 851           strp += 2;            /* skip \{ or \< */
 852           start = strp;
 853           start_idx = start - SDATA (string);
 854
 855           while ((strp - SDATA (string) < SBYTES (string))
 856                  && *strp != '}' && *strp != '>')
 857             strp++;
 858
 859           length_byte = strp - start;
 860           strp++;                       /* skip } or > */
 861
 862           /* Save STRP in IDX.  */
 863           idx = strp - SDATA (string);
 864
 865           /* Get the value of the keymap in TEM, or nil if undefined.
 866              Do this while still in the user's current buffer
 867              in case it is a local variable.  */
 868           name = Fintern (make_string ((char *) start, length_byte), Qnil);
 869           tem = Fboundp (name);
 870           if (! NILP (tem))
 871             {
 872               tem = Fsymbol_value (name);
 873               if (! NILP (tem))
 874                 {
 875                   tem = get_keymap (tem, 0, 1);
 876                   /* Note that get_keymap can GC.  */
 877                   strp = SDATA (string) + idx;
 878                   start = SDATA (string) + start_idx;
 879                 }
 880             }
 881
 882           /* Now switch to a temp buffer.  */
 883           oldbuf = current_buffer;
 884           set_buffer_internal (XBUFFER (Vprin1_to_string_buffer));
 885           /* This is for an unusual case where some after-change
 886              function uses 'format' or 'prin1' or something else that
 887              will thrash Vprin1_to_string_buffer we are using.  */
 888           specbind (Qinhibit_modification_hooks, Qt);
 889
 890           if (NILP (tem))
 891             {
 892               name = Fsymbol_name (name);
 893               insert_string ("\nUses keymap `");
 894               insert_from_string (name, 0, 0,
 895                                   SCHARS (name),
 896                                   SBYTES (name), 1);
 897               insert_string ("', which is not currently defined.\n");
 898               if (start[-1] == '<') keymap = Qnil;
 899             }
 900           else if (start[-1] == '<')
 901             keymap = tem;
 902           else
 903             {
 904               /* Get the list of active keymaps that precede this one.
 905                  If this one's not active, get nil.  */
 906               earlier_maps = Fcdr (Fmemq (tem, Freverse (active_maps)));
 907               describe_map_tree (tem, 1, Fnreverse (earlier_maps),
 908                                  Qnil, 0, 1, 0, 0, 1);
 909             }
 910           tem = Fbuffer_string ();
 911           Ferase_buffer ();
 912           set_buffer_internal (oldbuf);
 913           unbind_to (count, Qnil);
 914
 915         subst_string:
 916           start = SDATA (tem);
 917           length = SCHARS (tem);
 918           length_byte = SBYTES (tem);
 919         subst:
 920           {
 921             ptrdiff_t offset = bufp - buf;
 922             if (STRING_BYTES_BOUND - length_byte < bsize)
 923               string_overflow ();
 924             buf = xrealloc (buf, bsize += length_byte);
 925             bufp = buf + offset;
 926             memcpy (bufp, start, length_byte);
 927             bufp += length_byte;
 928             nchars += length;
 929             /* Check STRING again in case gc relocated it.  */
 930             strp = SDATA (string) + idx;
 931           }
 932         }
 933       else if (! multibyte)             /* just copy other chars */
 934         *bufp++ = *strp++, nchars++;
 935       else
 936         {
 937           int len;
 938
 939           STRING_CHAR_AND_LENGTH (strp, len);
 940           if (len == 1)
 941             *bufp = *strp;
 942           else
 943             memcpy (bufp, strp, len);
 944           strp += len;
 945           bufp += len;
 946           nchars++;
 947         }
 948     }
 949
 950   if (changed)                  /* don't bother if nothing substituted */
 951     tem = make_string_from_bytes (buf, nchars, bufp - buf);
 952   else
 953     tem = string;
 954   xfree (buf);
 955   RETURN_UNGCPRO (tem);
 956 }
 957 \f
 958 void
 959 syms_of_doc (void)
 960 {
 961   DEFSYM (Qfunction_documentation, "function-documentation");
 962
 963   DEFVAR_LISP ("internal-doc-file-name", Vdoc_file_name,
 964                doc: /* Name of file containing documentation strings of built-in symbols.  */);
 965   Vdoc_file_name = Qnil;
 966
 967   DEFVAR_LISP ("build-files", Vbuild_files,
 968                doc: /* A list of files used to build this Emacs binary.  */);
 969   Vbuild_files = Qnil;
 970
 971   defsubr (&Sdocumentation);
 972   defsubr (&Sdocumentation_property);
 973   defsubr (&Ssnarf_documentation);
 974   defsubr (&Ssubstitute_command_keys);
 975 }