src/doc.c

   1 /* Record indices of function doc strings stored in a file. -*- coding: utf-8 -*-
   2
   3 Copyright (C) 1985-1986, 1993-1995, 1997-2015 Free Software Foundation,
   4 Inc.
   5
   6 This file is part of GNU Emacs.
   7
   8 GNU Emacs is free software: you can redistribute it and/or modify
   9 it under the terms of the GNU General Public License as published by
  10 the Free Software Foundation, either version 3 of the License, or
  11 (at your option) any later version.
  12
  13 GNU Emacs is distributed in the hope that it will be useful,
  14 but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 GNU General Public License for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
  20
  21
  22 #include <config.h>
  23
  24 #include <errno.h>
  25 #include <sys/types.h>
  26 #include <sys/file.h>   /* Must be after sys/types.h for USG.  */
  27 #include <fcntl.h>
  28 #include <unistd.h>
  29
  30 #include <c-ctype.h>
  31
  32 #include "lisp.h"
  33 #include "character.h"
  34 #include "buffer.h"
  35 #include "disptab.h"
  36 #include "keyboard.h"
  37 #include "keymap.h"
  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 (NILP (file))
 304     Fsnarf_documentation (Vdoc_file_name);
 305   else
 306     Fload (file, Qt, Qt, Qt, Qnil);
 307
 308   return 1;
 309 }
 310
 311 DEFUN ("documentation", Fdocumentation, Sdocumentation, 1, 2, 0,
 312        doc: /* Return the documentation string of FUNCTION.
 313 Unless a non-nil second argument RAW is given, the
 314 string is passed through `substitute-command-keys'.  */)
 315   (Lisp_Object function, Lisp_Object raw)
 316 {
 317   Lisp_Object fun;
 318   Lisp_Object funcar;
 319   Lisp_Object doc;
 320   bool try_reload = 1;
 321
 322  documentation:
 323
 324   doc = Qnil;
 325
 326   if (SYMBOLP (function))
 327     {
 328       Lisp_Object tem = Fget (function, Qfunction_documentation);
 329       if (!NILP (tem))
 330         return Fdocumentation_property (function, Qfunction_documentation,
 331                                         raw);
 332     }
 333
 334   fun = Findirect_function (function, Qnil);
 335   if (CONSP (fun) && EQ (XCAR (fun), Qmacro))
 336     fun = XCDR (fun);
 337   if (SUBRP (fun))
 338     {
 339       if (XSUBR (fun)->doc == 0)
 340         return Qnil;
 341       /* FIXME: This is not portable, as it assumes that string
 342          pointers have the top bit clear.  */
 343       else if ((intptr_t) XSUBR (fun)->doc >= 0)
 344         doc = build_string (XSUBR (fun)->doc);
 345       else
 346         doc = make_number ((intptr_t) XSUBR (fun)->doc);
 347     }
 348   else if (COMPILEDP (fun))
 349     {
 350       if ((ASIZE (fun) & PSEUDOVECTOR_SIZE_MASK) <= COMPILED_DOC_STRING)
 351         return Qnil;
 352       else
 353         {
 354           Lisp_Object tem = AREF (fun, COMPILED_DOC_STRING);
 355           if (STRINGP (tem))
 356             doc = tem;
 357           else if (NATNUMP (tem) || CONSP (tem))
 358             doc = tem;
 359           else
 360             return Qnil;
 361         }
 362     }
 363   else if (STRINGP (fun) || VECTORP (fun))
 364     {
 365       return build_string ("Keyboard macro.");
 366     }
 367   else if (CONSP (fun))
 368     {
 369       funcar = XCAR (fun);
 370       if (!SYMBOLP (funcar))
 371         xsignal1 (Qinvalid_function, fun);
 372       else if (EQ (funcar, Qkeymap))
 373         return build_string ("Prefix command (definition is a keymap associating keystrokes with commands).");
 374       else if (EQ (funcar, Qlambda)
 375                || (EQ (funcar, Qclosure) && (fun = XCDR (fun), 1))
 376                || EQ (funcar, Qautoload))
 377         {
 378           Lisp_Object tem1 = Fcdr (Fcdr (fun));
 379           Lisp_Object tem = Fcar (tem1);
 380           if (STRINGP (tem))
 381             doc = tem;
 382           /* Handle a doc reference--but these never come last
 383              in the function body, so reject them if they are last.  */
 384           else if ((NATNUMP (tem) || (CONSP (tem) && INTEGERP (XCDR (tem))))
 385                    && !NILP (XCDR (tem1)))
 386             doc = tem;
 387           else
 388             return Qnil;
 389         }
 390       else
 391         goto oops;
 392     }
 393   else
 394     {
 395     oops:
 396       xsignal1 (Qinvalid_function, fun);
 397     }
 398
 399   /* If DOC is 0, it's typically because of a dumped file missing
 400      from the DOC file (bug in src/Makefile.in).  */
 401   if (EQ (doc, make_number (0)))
 402     doc = Qnil;
 403   if (INTEGERP (doc) || CONSP (doc))
 404     {
 405       Lisp_Object tem;
 406       tem = get_doc_string (doc, 0, 0);
 407       if (NILP (tem) && try_reload)
 408         {
 409           /* The file is newer, we need to reset the pointers.  */
 410           try_reload = reread_doc_file (Fcar_safe (doc));
 411           if (try_reload)
 412             {
 413               try_reload = 0;
 414               goto documentation;
 415             }
 416         }
 417       else
 418         doc = tem;
 419     }
 420
 421   if (NILP (raw))
 422     doc = Fsubstitute_command_keys (doc);
 423   return doc;
 424 }
 425
 426 DEFUN ("documentation-property", Fdocumentation_property,
 427        Sdocumentation_property, 2, 3, 0,
 428        doc: /* Return the documentation string that is SYMBOL's PROP property.
 429 Third argument RAW omitted or nil means pass the result through
 430 `substitute-command-keys' if it is a string.
 431
 432 This differs from `get' in that it can refer to strings stored in the
 433 `etc/DOC' file; and that it evaluates documentation properties that
 434 aren't strings.  */)
 435   (Lisp_Object symbol, Lisp_Object prop, Lisp_Object raw)
 436 {
 437   bool try_reload = 1;
 438   Lisp_Object tem;
 439
 440  documentation_property:
 441
 442   tem = Fget (symbol, prop);
 443   if (EQ (tem, make_number (0)))
 444     tem = Qnil;
 445   if (INTEGERP (tem) || (CONSP (tem) && INTEGERP (XCDR (tem))))
 446     {
 447       Lisp_Object doc = tem;
 448       tem = get_doc_string (tem, 0, 0);
 449       if (NILP (tem) && try_reload)
 450         {
 451           /* The file is newer, we need to reset the pointers.  */
 452           try_reload = reread_doc_file (Fcar_safe (doc));
 453           if (try_reload)
 454             {
 455               try_reload = 0;
 456               goto documentation_property;
 457             }
 458         }
 459     }
 460   else if (!STRINGP (tem))
 461     /* Feval protects its argument.  */
 462     tem = Feval (tem, Qnil);
 463
 464   if (NILP (raw) && STRINGP (tem))
 465     tem = Fsubstitute_command_keys (tem);
 466   return tem;
 467 }
 468 \f
 469 /* Scanning the DOC files and placing docstring offsets into functions.  */
 470
 471 static void
 472 store_function_docstring (Lisp_Object obj, ptrdiff_t offset)
 473 {
 474   /* Don't use indirect_function here, or defaliases will apply their
 475      docstrings to the base functions (Bug#2603).  */
 476   Lisp_Object fun = SYMBOLP (obj) ? XSYMBOL (obj)->function : obj;
 477
 478   /* The type determines where the docstring is stored.  */
 479
 480   /* Lisp_Subrs have a slot for it.  */
 481   if (SUBRP (fun))
 482     {
 483       intptr_t negative_offset = - offset;
 484       XSUBR (fun)->doc = (char *) negative_offset;
 485     }
 486
 487   /* If it's a lisp form, stick it in the form.  */
 488   else if (CONSP (fun))
 489     {
 490       Lisp_Object tem;
 491
 492       tem = XCAR (fun);
 493       if (EQ (tem, Qlambda) || EQ (tem, Qautoload)
 494           || (EQ (tem, Qclosure) && (fun = XCDR (fun), 1)))
 495         {
 496           tem = Fcdr (Fcdr (fun));
 497           if (CONSP (tem) && INTEGERP (XCAR (tem)))
 498             /* FIXME: This modifies typically pure hash-cons'd data, so its
 499                correctness is quite delicate.  */
 500             XSETCAR (tem, make_number (offset));
 501         }
 502       else if (EQ (tem, Qmacro))
 503         store_function_docstring (XCDR (fun), offset);
 504     }
 505
 506   /* Bytecode objects sometimes have slots for it.  */
 507   else if (COMPILEDP (fun))
 508     {
 509       /* This bytecode object must have a slot for the
 510          docstring, since we've found a docstring for it.  */
 511       if ((ASIZE (fun) & PSEUDOVECTOR_SIZE_MASK) > COMPILED_DOC_STRING)
 512         ASET (fun, COMPILED_DOC_STRING, make_number (offset));
 513       else
 514         {
 515           AUTO_STRING (format, "No docstring slot for %s");
 516           CALLN (Fmessage, format,
 517                  (SYMBOLP (obj)
 518                   ? SYMBOL_NAME (obj)
 519                   : build_string ("<anonymous>")));
 520         }
 521     }
 522 }
 523
 524
 525 DEFUN ("Snarf-documentation", Fsnarf_documentation, Ssnarf_documentation,
 526        1, 1, 0,
 527        doc: /* Used during Emacs initialization to scan the `etc/DOC...' file.
 528 This searches the `etc/DOC...' file for doc strings and
 529 records them in function and variable definitions.
 530 The function takes one argument, FILENAME, a string;
 531 it specifies the file name (without a directory) of the DOC file.
 532 That file is found in `../etc' now; later, when the dumped Emacs is run,
 533 the same file name is found in the `doc-directory'.  */)
 534   (Lisp_Object filename)
 535 {
 536   int fd;
 537   char buf[1024 + 1];
 538   int filled;
 539   EMACS_INT pos;
 540   Lisp_Object sym;
 541   char *p, *name;
 542   bool skip_file = 0;
 543   ptrdiff_t count;
 544   char const *dirname;
 545   ptrdiff_t dirlen;
 546   /* Preloaded defcustoms using custom-initialize-delay are added to
 547      this list, but kept unbound.  See http://debbugs.gnu.org/11565  */
 548   Lisp_Object delayed_init =
 549     find_symbol_value (intern ("custom-delayed-init-variables"));
 550
 551   if (EQ (delayed_init, Qunbound)) delayed_init = Qnil;
 552
 553   CHECK_STRING (filename);
 554
 555   if
 556 #ifndef CANNOT_DUMP
 557     (!NILP (Vpurify_flag))
 558 #else /* CANNOT_DUMP */
 559       (0)
 560 #endif /* CANNOT_DUMP */
 561     {
 562       dirname = sibling_etc;
 563       dirlen = sizeof sibling_etc - 1;
 564     }
 565   else
 566     {
 567       CHECK_STRING (Vdoc_directory);
 568       dirname = SSDATA (Vdoc_directory);
 569       dirlen = SBYTES (Vdoc_directory);
 570     }
 571
 572   count = SPECPDL_INDEX ();
 573   USE_SAFE_ALLOCA;
 574   name = SAFE_ALLOCA (dirlen + SBYTES (filename) + 1);
 575   lispstpcpy (stpcpy (name, dirname), filename);        /*** Add this line ***/
 576
 577   /* Vbuild_files is nil when temacs is run, and non-nil after that.  */
 578   if (NILP (Vbuild_files))
 579     {
 580       static char const *const buildobj[] =
 581         {
 582           #include "buildobj.h"
 583         };
 584       int i = ARRAYELTS (buildobj);
 585       while (0 <= --i)
 586         Vbuild_files = Fcons (build_string (buildobj[i]), Vbuild_files);
 587       Vbuild_files = Fpurecopy (Vbuild_files);
 588     }
 589
 590   fd = emacs_open (name, O_RDONLY, 0);
 591   if (fd < 0)
 592     {
 593       int open_errno = errno;
 594       report_file_errno ("Opening doc string file", build_string (name),
 595                          open_errno);
 596     }
 597   record_unwind_protect_int (close_file_unwind, fd);
 598   Vdoc_file_name = filename;
 599   filled = 0;
 600   pos = 0;
 601   while (1)
 602     {
 603       register char *end;
 604       if (filled < 512)
 605         filled += emacs_read (fd, &buf[filled], sizeof buf - 1 - filled);
 606       if (!filled)
 607         break;
 608
 609       buf[filled] = 0;
 610       end = buf + (filled < 512 ? filled : filled - 128);
 611       p = memchr (buf, '\037', end - buf);
 612       /* p points to ^_Ffunctionname\n or ^_Vvarname\n or ^_Sfilename\n.  */
 613       if (p)
 614         {
 615           end = strchr (p, '\n');
 616
 617           /* See if this is a file name, and if it is a file in build-files.  */
 618           if (p[1] == 'S')
 619             {
 620               skip_file = 0;
 621               if (end - p > 4 && end[-2] == '.'
 622                   && (end[-1] == 'o' || end[-1] == 'c'))
 623                 {
 624                   ptrdiff_t len = end - p - 2;
 625                   char *fromfile = SAFE_ALLOCA (len + 1);
 626                   memcpy (fromfile, &p[2], len);
 627                   fromfile[len] = 0;
 628                   if (fromfile[len-1] == 'c')
 629                     fromfile[len-1] = 'o';
 630
 631                   skip_file = NILP (Fmember (build_string (fromfile),
 632                                              Vbuild_files));
 633                 }
 634             }
 635
 636           sym = oblookup (Vobarray, p + 2,
 637                           multibyte_chars_in_text ((unsigned char *) p + 2,
 638                                                    end - p - 2),
 639                           end - p - 2);
 640           /* Check skip_file so that when a function is defined several
 641              times in different files (typically, once in xterm, once in
 642              w32term, ...), we only pay attention to the one that
 643              matters.  */
 644           if (! skip_file && SYMBOLP (sym))
 645             {
 646               /* Attach a docstring to a variable?  */
 647               if (p[1] == 'V')
 648                 {
 649                   /* Install file-position as variable-documentation property
 650                      and make it negative for a user-variable
 651                      (doc starts with a `*').  */
 652                   if (!NILP (Fboundp (sym))
 653                       || !NILP (Fmemq (sym, delayed_init)))
 654                     Fput (sym, Qvariable_documentation,
 655                           make_number ((pos + end + 1 - buf)
 656                                        * (end[1] == '*' ? -1 : 1)));
 657                 }
 658
 659               /* Attach a docstring to a function?  */
 660               else if (p[1] == 'F')
 661                 {
 662                   if (!NILP (Ffboundp (sym)))
 663                     store_function_docstring (sym, pos + end + 1 - buf);
 664                 }
 665               else if (p[1] == 'S')
 666                 ; /* Just a source file name boundary marker.  Ignore it.  */
 667
 668               else
 669                 error ("DOC file invalid at position %"pI"d", pos);
 670             }
 671         }
 672       pos += end - buf;
 673       filled -= end - buf;
 674       memmove (buf, end, filled);
 675     }
 676
 677   SAFE_FREE ();
 678   return unbind_to (count, Qnil);
 679 }
 680 \f
 681 /* Return true if text quoting style should default to quote `like this'.  */
 682 static bool
 683 default_to_grave_quoting_style (void)
 684 {
 685   if (!text_quoting_flag)
 686     return true;
 687   if (! DISP_TABLE_P (Vstandard_display_table))
 688     return false;
 689   Lisp_Object dv = DISP_CHAR_VECTOR (XCHAR_TABLE (Vstandard_display_table),
 690                                      LEFT_SINGLE_QUOTATION_MARK);
 691   return (VECTORP (dv) && ASIZE (dv) == 1
 692           && EQ (AREF (dv, 0), make_number ('`')));
 693 }
 694
 695 /* Return the current effective text quoting style.  */
 696 enum text_quoting_style
 697 text_quoting_style (void)
 698 {
 699   if (NILP (Vtext_quoting_style)
 700       ? default_to_grave_quoting_style ()
 701       : EQ (Vtext_quoting_style, Qgrave))
 702     return GRAVE_QUOTING_STYLE;
 703   else if (EQ (Vtext_quoting_style, Qstraight))
 704     return STRAIGHT_QUOTING_STYLE;
 705   else
 706     return CURVE_QUOTING_STYLE;
 707 }
 708
 709 DEFUN ("substitute-command-keys", Fsubstitute_command_keys,
 710        Ssubstitute_command_keys, 1, 1, 0,
 711        doc: /* Substitute key descriptions for command names in STRING.
 712 Each substring of the form \\=\\[COMMAND] is replaced by either a
 713 keystroke sequence that invokes COMMAND, or "M-x COMMAND" if COMMAND
 714 is not on any keys.
 715
 716 Each substring of the form \\=\\{MAPVAR} is replaced by a summary of
 717 the value of MAPVAR as a keymap.  This summary is similar to the one
 718 produced by `describe-bindings'.  The summary ends in two newlines
 719 (used by the helper function `help-make-xrefs' to find the end of the
 720 summary).
 721
 722 Each substring of the form \\=\\<MAPVAR> specifies the use of MAPVAR
 723 as the keymap for future \\=\\[COMMAND] substrings.
 724
 725 Each \\=‘ and \\=` is replaced by left quote, and each \\=’ and \\='
 726 is replaced by right quote.  Left and right quote characters are
 727 specified by `text-quoting-style'.
 728
 729 \\=\\= quotes the following character and is discarded; thus,
 730 \\=\\=\\=\\= puts \\=\\= into the output, \\=\\=\\=\\[ puts \\=\\[ into the output, and
 731 \\=\\=\\=` puts \\=` into the output.
 732
 733 Return the original STRING if no substitutions are made.
 734 Otherwise, return a new string.  */)
 735   (Lisp_Object string)
 736 {
 737   char *buf;
 738   bool changed = false;
 739   unsigned char *strp;
 740   char *bufp;
 741   ptrdiff_t idx;
 742   ptrdiff_t bsize;
 743   Lisp_Object tem;
 744   Lisp_Object keymap;
 745   unsigned char const *start;
 746   ptrdiff_t length, length_byte;
 747   Lisp_Object name;
 748   bool multibyte;
 749   ptrdiff_t nchars;
 750
 751   if (NILP (string))
 752     return Qnil;
 753
 754   CHECK_STRING (string);
 755   tem = Qnil;
 756   keymap = Qnil;
 757   name = Qnil;
 758
 759   enum text_quoting_style quoting_style = text_quoting_style ();
 760
 761   multibyte = STRING_MULTIBYTE (string);
 762   nchars = 0;
 763
 764   /* KEYMAP is either nil (which means search all the active keymaps)
 765      or a specified local map (which means search just that and the
 766      global map).  If non-nil, it might come from Voverriding_local_map,
 767      or from a \\<mapname> construct in STRING itself..  */
 768   keymap = Voverriding_local_map;
 769
 770   bsize = SBYTES (string);
 771
 772   /* Add some room for expansion due to quote replacement.  */
 773   enum { EXTRA_ROOM = 20 };
 774   if (bsize <= STRING_BYTES_BOUND - EXTRA_ROOM)
 775     bsize += EXTRA_ROOM;
 776
 777   bufp = buf = xmalloc (bsize);
 778
 779   strp = SDATA (string);
 780   while (strp < SDATA (string) + SBYTES (string))
 781     {
 782       if (strp[0] == '\\' && strp[1] == '=')
 783         {
 784           /* \= quotes the next character;
 785              thus, to put in \[ without its special meaning, use \=\[.  */
 786           changed = true;
 787           strp += 2;
 788           if (multibyte)
 789             {
 790               int len;
 791
 792               STRING_CHAR_AND_LENGTH (strp, len);
 793               if (len == 1)
 794                 *bufp = *strp;
 795               else
 796                 memcpy (bufp, strp, len);
 797               strp += len;
 798               bufp += len;
 799               nchars++;
 800             }
 801           else
 802             *bufp++ = *strp++, nchars++;
 803         }
 804       else if (strp[0] == '\\' && strp[1] == '[')
 805         {
 806           ptrdiff_t start_idx;
 807           bool follow_remap = 1;
 808
 809           strp += 2;            /* skip \[ */
 810           start = strp;
 811           start_idx = start - SDATA (string);
 812
 813           while ((strp - SDATA (string)
 814                   < SBYTES (string))
 815                  && *strp != ']')
 816             strp++;
 817           length_byte = strp - start;
 818
 819           strp++;               /* skip ] */
 820
 821           /* Save STRP in IDX.  */
 822           idx = strp - SDATA (string);
 823           name = Fintern (make_string ((char *) start, length_byte), Qnil);
 824
 825         do_remap:
 826           tem = Fwhere_is_internal (name, keymap, Qt, Qnil, Qnil);
 827
 828           if (VECTORP (tem) && ASIZE (tem) > 1
 829               && EQ (AREF (tem, 0), Qremap) && SYMBOLP (AREF (tem, 1))
 830               && follow_remap)
 831             {
 832               name = AREF (tem, 1);
 833               follow_remap = 0;
 834               goto do_remap;
 835             }
 836
 837           /* Note the Fwhere_is_internal can GC, so we have to take
 838              relocation of string contents into account.  */
 839           strp = SDATA (string) + idx;
 840           start = SDATA (string) + start_idx;
 841
 842           if (NILP (tem))       /* but not on any keys */
 843             {
 844               ptrdiff_t offset = bufp - buf;
 845               if (STRING_BYTES_BOUND - 4 < bsize)
 846                 string_overflow ();
 847               buf = xrealloc (buf, bsize += 4);
 848               bufp = buf + offset;
 849               memcpy (bufp, "M-x ", 4);
 850               bufp += 4;
 851               nchars += 4;
 852               if (multibyte)
 853                 length = multibyte_chars_in_text (start, length_byte);
 854               else
 855                 length = length_byte;
 856               goto subst;
 857             }
 858           else
 859             {                   /* function is on a key */
 860               tem = Fkey_description (tem, Qnil);
 861               goto subst_string;
 862             }
 863         }
 864       /* \{foo} is replaced with a summary of the keymap (symbol-value foo).
 865          \<foo> just sets the keymap used for \[cmd].  */
 866       else if (strp[0] == '\\' && (strp[1] == '{' || strp[1] == '<'))
 867         {
 868           struct buffer *oldbuf;
 869           ptrdiff_t start_idx;
 870           /* This is for computing the SHADOWS arg for describe_map_tree.  */
 871           Lisp_Object active_maps = Fcurrent_active_maps (Qnil, Qnil);
 872           Lisp_Object earlier_maps;
 873           ptrdiff_t count = SPECPDL_INDEX ();
 874
 875           strp += 2;            /* skip \{ or \< */
 876           start = strp;
 877           start_idx = start - SDATA (string);
 878
 879           while ((strp - SDATA (string) < SBYTES (string))
 880                  && *strp != '}' && *strp != '>')
 881             strp++;
 882
 883           length_byte = strp - start;
 884           strp++;                       /* skip } or > */
 885
 886           /* Save STRP in IDX.  */
 887           idx = strp - SDATA (string);
 888
 889           /* Get the value of the keymap in TEM, or nil if undefined.
 890              Do this while still in the user's current buffer
 891              in case it is a local variable.  */
 892           name = Fintern (make_string ((char *) start, length_byte), Qnil);
 893           tem = Fboundp (name);
 894           if (! NILP (tem))
 895             {
 896               tem = Fsymbol_value (name);
 897               if (! NILP (tem))
 898                 {
 899                   tem = get_keymap (tem, 0, 1);
 900                   /* Note that get_keymap can GC.  */
 901                   strp = SDATA (string) + idx;
 902                   start = SDATA (string) + start_idx;
 903                 }
 904             }
 905
 906           /* Now switch to a temp buffer.  */
 907           oldbuf = current_buffer;
 908           set_buffer_internal (XBUFFER (Vprin1_to_string_buffer));
 909           /* This is for an unusual case where some after-change
 910              function uses 'format' or 'prin1' or something else that
 911              will thrash Vprin1_to_string_buffer we are using.  */
 912           specbind (Qinhibit_modification_hooks, Qt);
 913
 914           if (NILP (tem))
 915             {
 916               name = Fsymbol_name (name);
 917               AUTO_STRING (msg_prefix, "\nUses keymap `");
 918               insert1 (Fsubstitute_command_keys (msg_prefix));
 919               insert_from_string (name, 0, 0,
 920                                   SCHARS (name),
 921                                   SBYTES (name), 1);
 922               AUTO_STRING (msg_suffix, "', which is not currently defined.\n");
 923               insert1 (Fsubstitute_command_keys (msg_suffix));
 924               if (start[-1] == '<') keymap = Qnil;
 925             }
 926           else if (start[-1] == '<')
 927             keymap = tem;
 928           else
 929             {
 930               /* Get the list of active keymaps that precede this one.
 931                  If this one's not active, get nil.  */
 932               earlier_maps = Fcdr (Fmemq (tem, Freverse (active_maps)));
 933               describe_map_tree (tem, 1, Fnreverse (earlier_maps),
 934                                  Qnil, 0, 1, 0, 0, 1);
 935             }
 936           tem = Fbuffer_string ();
 937           Ferase_buffer ();
 938           set_buffer_internal (oldbuf);
 939           unbind_to (count, Qnil);
 940
 941         subst_string:
 942           start = SDATA (tem);
 943           length = SCHARS (tem);
 944           length_byte = SBYTES (tem);
 945         subst:
 946           changed = true;
 947           {
 948             ptrdiff_t offset = bufp - buf;
 949             if (STRING_BYTES_BOUND - length_byte < bsize)
 950               string_overflow ();
 951             buf = xrealloc (buf, bsize += length_byte);
 952             bufp = buf + offset;
 953             memcpy (bufp, start, length_byte);
 954             bufp += length_byte;
 955             nchars += length;
 956             /* Check STRING again in case gc relocated it.  */
 957             strp = SDATA (string) + idx;
 958           }
 959         }
 960       else if ((strp[0] == '`' || strp[0] == '\'')
 961                && quoting_style == CURVE_QUOTING_STYLE)
 962         {
 963           start = (unsigned char const *) (strp[0] == '`' ? uLSQM : uRSQM);
 964           length = 1;
 965           length_byte = sizeof uLSQM - 1;
 966           idx = strp - SDATA (string) + 1;
 967           goto subst;
 968         }
 969       else if (strp[0] == '`' && quoting_style == STRAIGHT_QUOTING_STYLE)
 970         {
 971           *bufp++ = '\'';
 972           strp++;
 973           nchars++;
 974           changed = true;
 975         }
 976       else if (! multibyte)
 977         *bufp++ = *strp++, nchars++;
 978       else
 979         {
 980           int len;
 981           int ch = STRING_CHAR_AND_LENGTH (strp, len);
 982           if ((ch == LEFT_SINGLE_QUOTATION_MARK
 983                || ch == RIGHT_SINGLE_QUOTATION_MARK)
 984               && quoting_style != CURVE_QUOTING_STYLE)
 985             {
 986               *bufp++ = ((ch == LEFT_SINGLE_QUOTATION_MARK
 987                           && quoting_style == GRAVE_QUOTING_STYLE)
 988                          ? '`' : '\'');
 989               strp += len;
 990               changed = true;
 991             }
 992           else
 993             {
 994               do
 995                 *bufp++ = *strp++;
 996               while (--len != 0);
 997             }
 998           nchars++;
 999         }
1000     }
1001
1002   if (changed)                  /* don't bother if nothing substituted */
1003     tem = make_string_from_bytes (buf, nchars, bufp - buf);
1004   else
1005     tem = string;
1006   xfree (buf);
1007   return tem;
1008 }
1009 \f
1010 void
1011 syms_of_doc (void)
1012 {
1013   DEFSYM (Qfunction_documentation, "function-documentation");
1014   DEFSYM (Qgrave, "grave");
1015   DEFSYM (Qstraight, "straight");
1016
1017   DEFVAR_LISP ("internal-doc-file-name", Vdoc_file_name,
1018                doc: /* Name of file containing documentation strings of built-in symbols.  */);
1019   Vdoc_file_name = Qnil;
1020
1021   DEFVAR_LISP ("build-files", Vbuild_files,
1022                doc: /* A list of files used to build this Emacs binary.  */);
1023   Vbuild_files = Qnil;
1024
1025   DEFVAR_LISP ("text-quoting-style", Vtext_quoting_style,
1026                doc: /* Style to use for single quotes when generating text.
1027 `curve' means quote with curved single quotes \\=‘like this\\=’.
1028 `straight' means quote with straight apostrophes \\='like this\\='.
1029 `grave' means quote with grave accent and apostrophe \\=`like this\\='.
1030 The default value nil acts like `curve' if curved single quotes are
1031 displayable, and like `grave' otherwise.  */);
1032   Vtext_quoting_style = Qnil;
1033
1034   DEFVAR_BOOL ("internal--text-quoting-flag", text_quoting_flag,
1035                doc: /* If nil, a nil `text-quoting-style' is treated as `grave'.  */);
1036   /* Initialized by ‘main’.  */
1037
1038   defsubr (&Sdocumentation);
1039   defsubr (&Sdocumentation_property);
1040   defsubr (&Ssnarf_documentation);
1041   defsubr (&Ssubstitute_command_keys);
1042 }