libguile/load.c

   1 /*      Copyright (C) 1995,1996,1998,1999 Free Software Foundation, Inc.
   2  *
   3  * This program is free software; you can redistribute it and/or modify
   4  * it under the terms of the GNU General Public License as published by
   5  * the Free Software Foundation; either version 2, or (at your option)
   6  * any later version.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with this software; see the file COPYING.  If not, write to
  15  * the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  16  * Boston, MA 02111-1307 USA
  17  *
  18  * As a special exception, the Free Software Foundation gives permission
  19  * for additional uses of the text contained in its release of GUILE.
  20  *
  21  * The exception is that, if you link the GUILE library with other files
  22  * to produce an executable, this does not by itself cause the
  23  * resulting executable to be covered by the GNU General Public License.
  24  * Your use of that executable is in no way restricted on account of
  25  * linking the GUILE library code into it.
  26  *
  27  * This exception does not however invalidate any other reasons why
  28  * the executable file might be covered by the GNU General Public License.
  29  *
  30  * This exception applies only to the code released by the
  31  * Free Software Foundation under the name GUILE.  If you copy
  32  * code from other Free Software Foundation releases into a copy of
  33  * GUILE, as the General Public License permits, the exception does
  34  * not apply to the code that you add in this way.  To avoid misleading
  35  * anyone as to the status of such modified files, you must delete
  36  * this exception notice from them.
  37  *
  38  * If you write modifications of your own for GUILE, it is your choice
  39  * whether to permit this exception to apply to your modifications.
  40  * If you do not wish that, delete this exception notice.  */
  41
  42 /* Software engineering face-lift by Greg J. Badros, 11-Dec-1999,
  43    gjb@cs.washington.edu, http://www.cs.washington.edu/homes/gjb */
  44
  45 \f
  46
  47 #include <stdio.h>
  48 #include "libguile/_scm.h"
  49 #include "libguile/libpath.h"
  50 #include "libguile/fports.h"
  51 #include "libguile/read.h"
  52 #include "libguile/eval.h"
  53 #include "libguile/throw.h"
  54 #include "libguile/alist.h"
  55 #include "libguile/dynwind.h"
  56 #include "libguile/root.h"
  57 #include "libguile/strings.h"
  58
  59 #include "libguile/validate.h"
  60 #include "libguile/load.h"
  61
  62 #include <sys/types.h>
  63 #include <sys/stat.h>
  64
  65 #ifdef HAVE_UNISTD_H
  66 #include <unistd.h>
  67 #endif /* HAVE_UNISTD_H */
  68
  69 #ifndef R_OK
  70 #define R_OK 4
  71 #endif
  72
  73 \f
  74 /* Loading a file, given an absolute filename.  */
  75
  76 /* Hook to run when we load a file, perhaps to announce the fact somewhere.
  77    Applied to the full name of the file.  */
  78 static SCM *scm_loc_load_hook;
  79
  80 static void
  81 swap_port (void *data)
  82 {
  83   SCM *save_port = data, tmp = scm_cur_loadp;
  84   scm_cur_loadp = *save_port;
  85   *save_port = tmp;
  86 }
  87
  88 static SCM
  89 load (void *data)
  90 {
  91   SCM port = SCM_PACK (data);
  92   while (1)
  93     {
  94       SCM form = scm_read (port);
  95       if (SCM_EOF_OBJECT_P (form))
  96         break;
  97       scm_eval_x (form);
  98     }
  99   return SCM_UNSPECIFIED;
 100 }
 101
 102 SCM_DEFINE (scm_primitive_load, "primitive-load", 1, 0, 0,
 103            (SCM filename),
 104             "Load @var{file} and evaluate its contents in the top-level environment.\n"
 105             "The load paths are not searched; @var{file} must either be a full\n"
 106             "pathname or be a pathname relative to the current directory.  If the\n"
 107             "variable @code{%load-hook} is defined, it should be bound to a procedure\n"
 108             "that will be called before any code is loaded.  See documentation for\n"
 109             "@code{%load-hook} later in this section.")
 110 #define FUNC_NAME s_scm_primitive_load
 111 {
 112   SCM hook = *scm_loc_load_hook;
 113   SCM_VALIDATE_ROSTRING (1,filename);
 114   SCM_ASSERT (SCM_FALSEP (hook) || (SCM_TRUE_P (scm_procedure_p (hook))),
 115               hook, "value of %load-hook is neither a procedure nor #f",
 116               FUNC_NAME);
 117
 118   if (! SCM_FALSEP (hook))
 119     scm_apply (hook, scm_listify (filename, SCM_UNDEFINED), SCM_EOL);
 120
 121   { /* scope */
 122     SCM port, save_port;
 123     port = scm_open_file (filename,
 124                           scm_makfromstr ("r", (scm_sizet) sizeof (char), 0));
 125     save_port = port;
 126     scm_internal_dynamic_wind (swap_port,
 127                                load,
 128                                swap_port,
 129                                (void *) SCM_UNPACK (port),
 130                                &save_port);
 131     scm_close_port (port);
 132   }
 133   return SCM_UNSPECIFIED;
 134 }
 135 #undef FUNC_NAME
 136
 137 \f
 138 /* Builtin path to scheme library files. */
 139 #ifdef SCM_PKGDATA_DIR
 140 SCM_DEFINE (scm_sys_package_data_dir, "%package-data-dir", 0, 0, 0,
 141             (),
 142             "Return the name of the directory where Scheme packages, modules and\n"
 143             "libraries are kept.  On most Unix systems, this will be\n"
 144             "@samp{/usr/local/share/guile}.")
 145 #define FUNC_NAME s_scm_sys_package_data_dir
 146 {
 147   return scm_makfrom0str (SCM_PKGDATA_DIR);
 148 }
 149 #undef FUNC_NAME
 150 #endif /* SCM_PKGDATA_DIR */
 151
 152 #ifdef SCM_LIBRARY_DIR
 153 SCM_DEFINE (scm_sys_library_dir, "%library-dir", 0,0,0,
 154             (),
 155             "Return the directory where the Guile Scheme library files are installed.\n"
 156             "E.g., may return \"/usr/share/guile/1.3.5\".")
 157 #define FUNC_NAME s_scm_sys_library_dir
 158 {
 159   return scm_makfrom0str(SCM_LIBRARY_DIR);
 160 }
 161 #undef FUNC_NAME
 162 #endif /* SCM_LIBRARY_DIR */
 163
 164 #ifdef SCM_SITE_DIR
 165 SCM_DEFINE (scm_sys_site_dir, "%site-dir", 0,0,0,
 166             (),
 167             "Return the directory where the Guile site files are installed.\n"
 168             "E.g., may return \"/usr/share/guile/site\".")
 169 #define FUNC_NAME s_scm_sys_site_dir
 170 {
 171   return scm_makfrom0str(SCM_SITE_DIR);
 172 }
 173 #undef FUNC_NAME
 174 #endif /* SCM_SITE_DIR */
 175
 176
 177
 178 \f
 179 /* Initializing the load path, and searching it.  */
 180
 181 /* List of names of directories we search for files to load.  */
 182 static SCM *scm_loc_load_path;
 183
 184 /* List of extensions we try adding to the filenames.  */
 185 static SCM *scm_loc_load_extensions;
 186
 187
 188 /* Parse the null-terminated string PATH as if it were a standard path
 189    environment variable (i.e. a colon-separated list of strings), and
 190    prepend the elements to TAIL.  */
 191 SCM
 192 scm_internal_parse_path (char *path, SCM tail)
 193 {
 194   if (path && path[0] != '\0')
 195     {
 196       char *scan, *elt_end;
 197
 198       /* Scan backwards from the end of the string, to help
 199          construct the list in the right order.  */
 200       scan = elt_end = path + strlen (path);
 201       do {
 202         /* Scan back to the beginning of the current element.  */
 203         do scan--;
 204         while (scan >= path && *scan != ':');
 205         tail = scm_cons (scm_makfromstr (scan + 1, elt_end - (scan + 1), 0),
 206                          tail);
 207         elt_end = scan;
 208       } while (scan >= path);
 209     }
 210
 211   return tail;
 212 }
 213
 214
 215 SCM_DEFINE (scm_parse_path, "parse-path", 1, 1, 0,
 216             (SCM path, SCM tail),
 217             "")
 218 #define FUNC_NAME s_scm_parse_path
 219 {
 220   SCM_ASSERT (SCM_FALSEP (path) || (SCM_ROSTRINGP (path)),
 221               path,
 222               SCM_ARG1, FUNC_NAME);
 223   if (SCM_UNBNDP (tail))
 224     tail = SCM_EOL;
 225   return (SCM_FALSEP (path)
 226           ? tail
 227           : scm_internal_parse_path (SCM_ROCHARS (path), tail));
 228 }
 229 #undef FUNC_NAME
 230
 231
 232 /* Initialize the global variable %load-path, given the value of the
 233    SCM_SITE_DIR and SCM_LIBRARY_DIR preprocessor symbols and the
 234    GUILE_LOAD_PATH environment variable.  */
 235 void
 236 scm_init_load_path ()
 237 {
 238   SCM path = SCM_EOL;
 239
 240 #ifdef SCM_LIBRARY_DIR
 241   path = scm_listify (scm_makfrom0str (SCM_SITE_DIR),
 242                       scm_makfrom0str (SCM_LIBRARY_DIR),
 243                       scm_makfrom0str (SCM_PKGDATA_DIR),
 244                       SCM_UNDEFINED);
 245 #endif /* SCM_LIBRARY_DIR */
 246
 247   path = scm_internal_parse_path (getenv ("GUILE_LOAD_PATH"), path);
 248
 249   *scm_loc_load_path = path;
 250 }
 251
 252 SCM scm_listofnullstr;
 253
 254 /* Search PATH for a directory containing a file named FILENAME.
 255    The file must be readable, and not a directory.
 256    If we find one, return its full filename; otherwise, return #f.
 257    If FILENAME is absolute, return it unchanged.
 258    If given, EXTENSIONS is a list of strings; for each directory
 259    in PATH, we search for FILENAME concatenated with each EXTENSION.  */
 260 SCM_DEFINE (scm_search_path, "search-path", 2, 1, 0,
 261            (SCM path, SCM filename, SCM extensions),
 262             "")
 263 #define FUNC_NAME s_scm_search_path
 264 {
 265   char *filename_chars;
 266   int filename_len;
 267   size_t max_path_len;          /* maximum length of any PATH element */
 268   size_t max_ext_len;           /* maximum length of any EXTENSIONS element */
 269
 270   SCM_VALIDATE_LIST (1,path);
 271   SCM_VALIDATE_ROSTRING (2,filename);
 272   if (SCM_UNBNDP (extensions))
 273     extensions = SCM_EOL;
 274   else
 275     SCM_VALIDATE_LIST (3,extensions);
 276
 277   filename_chars = SCM_ROCHARS (filename);
 278   filename_len = SCM_ROLENGTH (filename);
 279
 280   /* If FILENAME is absolute, return it unchanged.  */
 281   if (filename_len >= 1 && filename_chars[0] == '/')
 282     return filename;
 283
 284   /* Find the length of the longest element of path.  */
 285   {
 286     SCM walk;
 287
 288     max_path_len = 0;
 289     for (walk = path; SCM_NNULLP (walk); walk = SCM_CDR (walk))
 290       {
 291         SCM elt = SCM_CAR (walk);
 292         SCM_ASSERT (SCM_ROSTRINGP (elt), elt,
 293                     "path is not a list of strings",
 294                     FUNC_NAME);
 295         if (SCM_ROLENGTH (elt) > max_path_len)
 296           max_path_len = SCM_ROLENGTH (elt);
 297       }
 298   }
 299
 300   /* If FILENAME has an extension, don't try to add EXTENSIONS to it.  */
 301   {
 302     char *endp;
 303
 304     for (endp = filename_chars + filename_len - 1;
 305          endp >= filename_chars;
 306          endp--)
 307       {
 308         if (*endp == '.')
 309           {
 310             /* This filename already has an extension, so cancel the
 311                list of extensions.  */
 312             extensions = SCM_EOL;
 313             break;
 314           }
 315         else if (*endp == '/')
 316           /* This filename has no extension, so keep the current list
 317              of extensions.  */
 318           break;
 319       }
 320   }
 321
 322   /* Find the length of the longest element of the load extensions
 323      list.  */
 324   { /* scope */
 325     SCM walk;
 326
 327     max_ext_len = 0;
 328     for (walk = extensions; SCM_NNULLP (walk); walk = SCM_CDR (walk))
 329       {
 330         SCM elt = SCM_CAR (walk);
 331         SCM_ASSERT (SCM_ROSTRINGP (elt), elt,
 332                     "extension list is not a list of strings",
 333                     FUNC_NAME);
 334         if (SCM_ROLENGTH (elt) > max_ext_len)
 335           max_ext_len = SCM_ROLENGTH (elt);
 336       }
 337   }
 338
 339   SCM_DEFER_INTS;
 340
 341   { /* scope */
 342     SCM result = SCM_BOOL_F;
 343     int buf_size = max_path_len + 1 + filename_len + max_ext_len + 1;
 344     char *buf = SCM_MUST_MALLOC (buf_size);
 345
 346     /* This simplifies the loop below a bit.  */
 347     if (SCM_NULLP (extensions))
 348       extensions = scm_listofnullstr;
 349
 350     /* Try every path element.  At this point, we know the path is a
 351        proper list of strings.  */
 352     for (; SCM_NNULLP (path); path = SCM_CDR (path))
 353       {
 354         int len;
 355         SCM dir = SCM_CAR (path);
 356         SCM exts;
 357
 358         /* Concatenate the path name and the filename. */
 359         len = SCM_ROLENGTH (dir);
 360         memcpy (buf, SCM_ROCHARS (dir), len);
 361         if (len >= 1 && buf[len - 1] != '/')
 362           buf[len++] = '/';
 363         memcpy (buf + len, filename_chars, filename_len);
 364         len += filename_len;
 365
 366         /* Try every extension.  At this point, we know the extension
 367            list is a proper, nonempty list of strings.  */
 368         for (exts = extensions; SCM_NNULLP (exts); exts = SCM_CDR (exts))
 369           {
 370             SCM ext = SCM_CAR (exts);
 371             int ext_len = SCM_ROLENGTH (ext);
 372             struct stat mode;
 373
 374             /* Concatenate the extension. */
 375             memcpy (buf + len, SCM_ROCHARS (ext), ext_len);
 376             buf[len + ext_len] = '\0';
 377
 378             /* If the file exists at all, we should return it.  If the
 379                file is inaccessible, then that's an error.  */
 380             if (stat (buf, &mode) == 0
 381                 && ! (mode.st_mode & S_IFDIR))
 382               {
 383                 result = scm_makfromstr (buf, len + ext_len, 0);
 384                 goto end;
 385               }
 386           }
 387       }
 388
 389   end:
 390     scm_must_free (buf);
 391     scm_done_malloc (- buf_size);
 392     SCM_ALLOW_INTS;
 393     return result;
 394   }
 395 }
 396 #undef FUNC_NAME
 397
 398
 399 /* Search %load-path for a directory containing a file named FILENAME.
 400    The file must be readable, and not a directory.
 401    If we find one, return its full filename; otherwise, return #f.
 402    If FILENAME is absolute, return it unchanged.  */
 403 SCM_DEFINE (scm_sys_search_load_path, "%search-load-path", 1, 0, 0,
 404            (SCM filename),
 405             "Search @var{%load-path} for @var{file}, which must be readable by the\n"
 406             "current user.  If @var{file} is found in the list of paths to search or\n"
 407             "is an absolute pathname, return its full pathname.  Otherwise, return\n"
 408             "@code{#f}.  Filenames may have any of the optional extensions in the\n"
 409             "@code{%load-extensions} list; @code{%search-load-path} will try each\n"
 410             "extension automatically.")
 411 #define FUNC_NAME s_scm_sys_search_load_path
 412 {
 413   SCM path = *scm_loc_load_path;
 414   SCM exts = *scm_loc_load_extensions;
 415   SCM_VALIDATE_ROSTRING (1,filename);
 416
 417   SCM_ASSERT (scm_ilength (path) >= 0, path, "load path is not a proper list",
 418               FUNC_NAME);
 419   SCM_ASSERT (scm_ilength (exts) >= 0, exts,
 420               "load extension list is not a proper list",
 421               FUNC_NAME);
 422   return scm_search_path (path, filename, exts);
 423 }
 424 #undef FUNC_NAME
 425
 426
 427 SCM_DEFINE (scm_primitive_load_path, "primitive-load-path", 1, 0, 0,
 428            (SCM filename),
 429             "Search @var{%load-path} for @var{file} and load it into the top-level\n"
 430             "environment.  If @var{file} is a relative pathname and is not found in\n"
 431             "the list of search paths, an error is signalled.")
 432 #define FUNC_NAME s_scm_primitive_load_path
 433 {
 434   SCM full_filename;
 435
 436   SCM_VALIDATE_ROSTRING (1,filename);
 437
 438   full_filename = scm_sys_search_load_path (filename);
 439
 440   if (SCM_FALSEP (full_filename))
 441     {
 442       int absolute = (SCM_ROLENGTH (filename) >= 1
 443                       && SCM_ROCHARS (filename)[0] == '/');
 444       SCM_MISC_ERROR ((absolute
 445                        ? "Unable to load file ~S"
 446                        : "Unable to find file ~S in load path"),
 447                       scm_listify (filename, SCM_UNDEFINED));
 448     }
 449
 450   return scm_primitive_load (full_filename);
 451 }
 452 #undef FUNC_NAME
 453
 454 /* The following function seems trivial - and indeed it is.  Its
 455  * existence is motivated by its ability to evaluate expressions
 456  * without copying them first (as is done in "eval").
 457  */
 458
 459 SCM_SYMBOL (scm_end_of_file_key, "end-of-file");
 460
 461 SCM_DEFINE (scm_read_and_eval_x, "read-and-eval!", 0, 1, 0,
 462             (SCM port),
 463             "Read a form from @var{port} (standard input by default), and evaluate it\n"
 464             "(memoizing it in the process) in the top-level environment.  If no data\n"
 465             "is left to be read from @var{port}, an @code{end-of-file} error is\n"
 466             "signalled.")
 467 #define FUNC_NAME s_scm_read_and_eval_x
 468 {
 469   SCM form = scm_read (port);
 470   if (SCM_EOF_OBJECT_P (form))
 471     scm_ithrow (scm_end_of_file_key, SCM_EOL, 1);
 472   return scm_eval_x (form);
 473 }
 474 #undef FUNC_NAME
 475
 476 \f
 477 /* Information about the build environment.  */
 478
 479 /* Initialize the scheme variable %guile-build-info, based on data
 480    provided by the Makefile, via libpath.h.  */
 481 static void
 482 init_build_info ()
 483 {
 484   static struct { char *name; char *value; } info[] = SCM_BUILD_INFO;
 485   SCM *loc = SCM_CDRLOC (scm_sysintern ("%guile-build-info", SCM_EOL));
 486   unsigned int i;
 487
 488   for (i = 0; i < (sizeof (info) / sizeof (info[0])); i++)
 489     *loc = scm_acons (SCM_CAR (scm_intern0 (info[i].name)),
 490                       scm_makfrom0str (info[i].value),
 491                       *loc);
 492 }
 493
 494
 495 \f
 496 void
 497 scm_init_load ()
 498 {
 499   scm_listofnullstr = scm_permanent_object (SCM_LIST1 (scm_nullstr));
 500   scm_loc_load_path = SCM_CDRLOC (scm_sysintern ("%load-path", SCM_EOL));
 501   scm_loc_load_extensions
 502     = SCM_CDRLOC (scm_sysintern ("%load-extensions",
 503                                  scm_listify (scm_makfrom0str (".scm"),
 504                                               scm_makfrom0str (""),
 505                                               SCM_UNDEFINED)));
 506   scm_loc_load_hook = SCM_CDRLOC (scm_sysintern ("%load-hook", SCM_BOOL_F));
 507
 508   init_build_info ();
 509
 510 #include "libguile/load.x"
 511 }
 512
 513 /*
 514   Local Variables:
 515   c-file-style: "gnu"
 516   End:
 517 */