libguile/load.c

   1 /* Copyright (C) 1995,1996,1998,1999,2000,2001 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
  43 \f
  44
  45 #include <string.h>
  46
  47 #include "libguile/_scm.h"
  48 #include "libguile/libpath.h"
  49 #include "libguile/fports.h"
  50 #include "libguile/read.h"
  51 #include "libguile/eval.h"
  52 #include "libguile/throw.h"
  53 #include "libguile/alist.h"
  54 #include "libguile/dynwind.h"
  55 #include "libguile/root.h"
  56 #include "libguile/strings.h"
  57 #include "libguile/modules.h"
  58 #include "libguile/lang.h"
  59
  60 #include "libguile/validate.h"
  61 #include "libguile/load.h"
  62
  63 #include <sys/types.h>
  64 #include <sys/stat.h>
  65
  66 #ifdef HAVE_UNISTD_H
  67 #include <unistd.h>
  68 #endif /* HAVE_UNISTD_H */
  69
  70 #ifndef R_OK
  71 #define R_OK 4
  72 #endif
  73
  74 \f
  75 /* Loading a file, given an absolute filename.  */
  76
  77 /* Hook to run when we load a file, perhaps to announce the fact somewhere.
  78    Applied to the full name of the file.  */
  79 static SCM *scm_loc_load_hook;
  80
  81 static void
  82 swap_port (void *data)
  83 {
  84   SCM *save_port = data, tmp = scm_cur_loadp;
  85   scm_cur_loadp = *save_port;
  86   *save_port = tmp;
  87 }
  88
  89 static SCM
  90 load (void *data)
  91 {
  92   SCM port = SCM_PACK (data);
  93   while (1)
  94     {
  95       SCM form = scm_read (port);
  96       if (SCM_EOF_OBJECT_P (form))
  97         break;
  98       scm_primitive_eval_x (form);
  99     }
 100   return SCM_UNSPECIFIED;
 101 }
 102
 103 SCM_DEFINE (scm_primitive_load, "primitive-load", 1, 0, 0,
 104            (SCM filename),
 105             "Load the file named @var{filename} and evaluate its contents in\n"
 106             "the top-level environment. The load paths are not searched;\n"
 107             "@var{filename} must either be a full pathname or be a pathname\n"
 108             "relative to the current directory.  If the  variable\n"
 109             "@code{%load-hook} is defined, it should be bound to a procedure\n"
 110             "that will be called before any code is loaded.  See the\n"
 111             "documentation for @code{%load-hook} later in this section.")
 112 #define FUNC_NAME s_scm_primitive_load
 113 {
 114   SCM hook = *scm_loc_load_hook;
 115   SCM_VALIDATE_STRING (1, filename);
 116   if (!SCM_FALSEP (hook) && !SCM_EQ_P (scm_procedure_p (hook), SCM_BOOL_T))
 117     SCM_MISC_ERROR ("value of %load-hook is neither a procedure nor #f",
 118                     SCM_EOL);
 119
 120   if (! SCM_FALSEP (hook))
 121     scm_call_1 (hook, filename);
 122
 123   { /* scope */
 124     SCM port, save_port;
 125     port = scm_open_file (filename, scm_mem2string ("r", sizeof (char)));
 126     save_port = port;
 127     scm_internal_dynamic_wind (swap_port,
 128                                load,
 129                                swap_port,
 130                                (void *) SCM_UNPACK (port),
 131                                &save_port);
 132     scm_close_port (port);
 133   }
 134   return SCM_UNSPECIFIED;
 135 }
 136 #undef FUNC_NAME
 137
 138 SCM
 139 scm_c_primitive_load (const char *filename)
 140 {
 141   return scm_primitive_load (scm_makfrom0str (filename));
 142 }
 143
 144 \f
 145 /* Builtin path to scheme library files. */
 146 #ifdef SCM_PKGDATA_DIR
 147 SCM_DEFINE (scm_sys_package_data_dir, "%package-data-dir", 0, 0, 0,
 148             (),
 149             "Return the name of the directory where Scheme packages, modules and\n"
 150             "libraries are kept.  On most Unix systems, this will be\n"
 151             "@samp{/usr/local/share/guile}.")
 152 #define FUNC_NAME s_scm_sys_package_data_dir
 153 {
 154   return scm_makfrom0str (SCM_PKGDATA_DIR);
 155 }
 156 #undef FUNC_NAME
 157 #endif /* SCM_PKGDATA_DIR */
 158
 159 #ifdef SCM_LIBRARY_DIR
 160 SCM_DEFINE (scm_sys_library_dir, "%library-dir", 0,0,0,
 161             (),
 162             "Return the directory where the Guile Scheme library files are installed.\n"
 163             "E.g., may return \"/usr/share/guile/1.3.5\".")
 164 #define FUNC_NAME s_scm_sys_library_dir
 165 {
 166   return scm_makfrom0str(SCM_LIBRARY_DIR);
 167 }
 168 #undef FUNC_NAME
 169 #endif /* SCM_LIBRARY_DIR */
 170
 171 #ifdef SCM_SITE_DIR
 172 SCM_DEFINE (scm_sys_site_dir, "%site-dir", 0,0,0,
 173             (),
 174             "Return the directory where the Guile site files are installed.\n"
 175             "E.g., may return \"/usr/share/guile/site\".")
 176 #define FUNC_NAME s_scm_sys_site_dir
 177 {
 178   return scm_makfrom0str(SCM_SITE_DIR);
 179 }
 180 #undef FUNC_NAME
 181 #endif /* SCM_SITE_DIR */
 182
 183
 184
 185 \f
 186 /* Initializing the load path, and searching it.  */
 187
 188 /* List of names of directories we search for files to load.  */
 189 static SCM *scm_loc_load_path;
 190
 191 /* List of extensions we try adding to the filenames.  */
 192 static SCM *scm_loc_load_extensions;
 193
 194
 195 /* Parse the null-terminated string PATH as if it were a standard path
 196    environment variable (i.e. a colon-separated list of strings), and
 197    prepend the elements to TAIL.  */
 198 SCM
 199 scm_internal_parse_path (char *path, SCM tail)
 200 {
 201   if (path && path[0] != '\0')
 202     {
 203       char *scan, *elt_end;
 204
 205       /* Scan backwards from the end of the string, to help
 206          construct the list in the right order.  */
 207       scan = elt_end = path + strlen (path);
 208       do {
 209         /* Scan back to the beginning of the current element.  */
 210         do scan--;
 211         while (scan >= path && *scan != ':');
 212         tail = scm_cons (scm_mem2string (scan + 1, elt_end - (scan + 1)),
 213                          tail);
 214         elt_end = scan;
 215       } while (scan >= path);
 216     }
 217
 218   return tail;
 219 }
 220
 221
 222 SCM_DEFINE (scm_parse_path, "parse-path", 1, 1, 0,
 223             (SCM path, SCM tail),
 224             "Parse @var{path}, which is expected to be a colon-separated\n"
 225             "string, into a list and return the resulting list with\n"
 226             "@var{tail} appended. If @var{path} is @code{#f}, @var{tail}\n"
 227             "is returned.")
 228 #define FUNC_NAME s_scm_parse_path
 229 {
 230   SCM_ASSERT (SCM_FALSEP (path) || (SCM_STRINGP (path)),
 231               path,
 232               SCM_ARG1, FUNC_NAME);
 233   if (SCM_UNBNDP (tail))
 234     tail = SCM_EOL;
 235   return (SCM_FALSEP (path)
 236           ? tail
 237           : scm_internal_parse_path (SCM_STRING_CHARS (path), tail));
 238 }
 239 #undef FUNC_NAME
 240
 241
 242 /* Initialize the global variable %load-path, given the value of the
 243    SCM_SITE_DIR and SCM_LIBRARY_DIR preprocessor symbols and the
 244    GUILE_LOAD_PATH environment variable.  */
 245 void
 246 scm_init_load_path ()
 247 {
 248   SCM path = SCM_EOL;
 249
 250 #ifdef SCM_LIBRARY_DIR
 251   path = scm_list_3 (scm_makfrom0str (SCM_SITE_DIR),
 252                      scm_makfrom0str (SCM_LIBRARY_DIR),
 253                      scm_makfrom0str (SCM_PKGDATA_DIR));
 254 #endif /* SCM_LIBRARY_DIR */
 255
 256   path = scm_internal_parse_path (getenv ("GUILE_LOAD_PATH"), path);
 257
 258   *scm_loc_load_path = path;
 259 }
 260
 261 SCM scm_listofnullstr;
 262
 263 /* Search PATH for a directory containing a file named FILENAME.
 264    The file must be readable, and not a directory.
 265    If we find one, return its full filename; otherwise, return #f.
 266    If FILENAME is absolute, return it unchanged.
 267    If given, EXTENSIONS is a list of strings; for each directory
 268    in PATH, we search for FILENAME concatenated with each EXTENSION.  */
 269 SCM_DEFINE (scm_search_path, "search-path", 2, 1, 0,
 270            (SCM path, SCM filename, SCM extensions),
 271             "Search @var{path} for a directory containing a file named\n"
 272             "@var{filename}. The file must be readable, and not a directory.\n"
 273             "If we find one, return its full filename; otherwise, return\n"
 274             "@code{#f}.  If @var{filename} is absolute, return it unchanged.\n"
 275             "If given, @var{extensions} is a list of strings; for each\n"
 276             "directory in @var{path}, we search for @var{filename}\n"
 277             "concatenated with each @var{extension}.")
 278 #define FUNC_NAME s_scm_search_path
 279 {
 280   char *filename_chars;
 281   int filename_len;
 282   size_t max_path_len;          /* maximum length of any PATH element */
 283   size_t max_ext_len;           /* maximum length of any EXTENSIONS element */
 284
 285   SCM_VALIDATE_LIST (1,path);
 286   SCM_VALIDATE_STRING (2, filename);
 287   if (SCM_UNBNDP (extensions))
 288     extensions = SCM_EOL;
 289   else
 290     SCM_VALIDATE_LIST (3,extensions);
 291
 292   filename_chars = SCM_STRING_CHARS (filename);
 293   filename_len = SCM_STRING_LENGTH (filename);
 294
 295   /* If FILENAME is absolute, return it unchanged.  */
 296   if (filename_len >= 1 && filename_chars[0] == '/')
 297     return filename;
 298
 299   /* Find the length of the longest element of path.  */
 300   {
 301     SCM walk;
 302
 303     max_path_len = 0;
 304     for (walk = path; !SCM_NULL_OR_NIL_P (walk); walk = SCM_CDR (walk))
 305       {
 306         SCM elt = SCM_CAR (walk);
 307         SCM_ASSERT_TYPE (SCM_STRINGP (elt), path, 1, FUNC_NAME,
 308                          "list of strings");
 309         if (SCM_STRING_LENGTH (elt) > max_path_len)
 310           max_path_len = SCM_STRING_LENGTH (elt);
 311       }
 312   }
 313
 314   /* If FILENAME has an extension, don't try to add EXTENSIONS to it.  */
 315   {
 316     char *endp;
 317
 318     for (endp = filename_chars + filename_len - 1;
 319          endp >= filename_chars;
 320          endp--)
 321       {
 322         if (*endp == '.')
 323           {
 324             /* This filename already has an extension, so cancel the
 325                list of extensions.  */
 326             extensions = SCM_EOL;
 327             break;
 328           }
 329         else if (*endp == '/')
 330           /* This filename has no extension, so keep the current list
 331              of extensions.  */
 332           break;
 333       }
 334   }
 335
 336   /* Find the length of the longest element of the load extensions
 337      list.  */
 338   { /* scope */
 339     SCM walk;
 340
 341     max_ext_len = 0;
 342     for (walk = extensions; !SCM_NULL_OR_NIL_P (walk); walk = SCM_CDR (walk))
 343       {
 344         SCM elt = SCM_CAR (walk);
 345         SCM_ASSERT_TYPE (SCM_STRINGP (elt), elt, 3, FUNC_NAME,
 346                          "list of strings");
 347         if (SCM_STRING_LENGTH (elt) > max_ext_len)
 348           max_ext_len = SCM_STRING_LENGTH (elt);
 349       }
 350   }
 351
 352   SCM_DEFER_INTS;
 353
 354   { /* scope */
 355     SCM result = SCM_BOOL_F;
 356     size_t buf_size = max_path_len + 1 + filename_len + max_ext_len + 1;
 357     char *buf = scm_malloc (buf_size);
 358
 359     /* This simplifies the loop below a bit.  */
 360     if (SCM_NULL_OR_NIL_P (extensions))
 361       extensions = scm_listofnullstr;
 362
 363     /* Try every path element.  At this point, we know the path is a
 364        proper list of strings.  */
 365     for (; !SCM_NULL_OR_NIL_P (path); path = SCM_CDR (path))
 366       {
 367         size_t len;
 368         SCM dir = SCM_CAR (path);
 369         SCM exts;
 370
 371         /* Concatenate the path name and the filename. */
 372         len = SCM_STRING_LENGTH (dir);
 373         memcpy (buf, SCM_STRING_CHARS (dir), len);
 374         if (len >= 1 && buf[len - 1] != '/')
 375           buf[len++] = '/';
 376         memcpy (buf + len, filename_chars, filename_len);
 377         len += filename_len;
 378
 379         /* Try every extension.  At this point, we know the extension
 380            list is a proper, nonempty list of strings.  */
 381         for (exts = extensions; !SCM_NULL_OR_NIL_P (exts); exts = SCM_CDR (exts))
 382           {
 383             SCM ext = SCM_CAR (exts);
 384             size_t ext_len = SCM_STRING_LENGTH (ext);
 385             struct stat mode;
 386
 387             /* Concatenate the extension. */
 388             memcpy (buf + len, SCM_STRING_CHARS (ext), ext_len);
 389             buf[len + ext_len] = '\0';
 390
 391             /* If the file exists at all, we should return it.  If the
 392                file is inaccessible, then that's an error.  */
 393             if (stat (buf, &mode) == 0
 394                 && ! (mode.st_mode & S_IFDIR))
 395               {
 396                 result = scm_mem2string (buf, len + ext_len);
 397                 goto end;
 398               }
 399           }
 400       }
 401
 402   end:
 403     free (buf);
 404     SCM_ALLOW_INTS;
 405     return result;
 406   }
 407 }
 408 #undef FUNC_NAME
 409
 410
 411 /* Search %load-path for a directory containing a file named FILENAME.
 412    The file must be readable, and not a directory.
 413    If we find one, return its full filename; otherwise, return #f.
 414    If FILENAME is absolute, return it unchanged.  */
 415 SCM_DEFINE (scm_sys_search_load_path, "%search-load-path", 1, 0, 0,
 416             (SCM filename),
 417             "Search @var{%load-path} for the file named @var{filename},\n"
 418             "which must be readable by the current user.  If @var{filename}\n"
 419             "is found in the list of paths to search or is an absolute\n"
 420             "pathname, return its full pathname.  Otherwise, return\n"
 421             "@code{#f}.  Filenames may have any of the optional extensions\n"
 422             "in the @code{%load-extensions} list; @code{%search-load-path}\n"
 423             "will try each extension automatically.")
 424 #define FUNC_NAME s_scm_sys_search_load_path
 425 {
 426   SCM path = *scm_loc_load_path;
 427   SCM exts = *scm_loc_load_extensions;
 428   SCM_VALIDATE_STRING (1, filename);
 429
 430   if (scm_ilength (path) < 0)
 431     SCM_MISC_ERROR ("%load-path is not a proper list", SCM_EOL);
 432   if (scm_ilength (exts) < 0)
 433     SCM_MISC_ERROR ("%load-extension list is not a proper list", SCM_EOL);
 434   return scm_search_path (path, filename, exts);
 435 }
 436 #undef FUNC_NAME
 437
 438
 439 SCM_DEFINE (scm_primitive_load_path, "primitive-load-path", 1, 0, 0,
 440             (SCM filename),
 441             "Search @var{%load-path} for the file named @var{filename} and\n"
 442             "load it into the top-level environment.  If @var{filename} is a\n"
 443             "relative pathname and is not found in the list of search paths,\n"
 444             "an error is signalled.")
 445 #define FUNC_NAME s_scm_primitive_load_path
 446 {
 447   SCM full_filename;
 448
 449   SCM_VALIDATE_STRING (1, filename);
 450
 451   full_filename = scm_sys_search_load_path (filename);
 452
 453   if (SCM_FALSEP (full_filename))
 454     {
 455       int absolute = (SCM_STRING_LENGTH (filename) >= 1
 456                       && SCM_STRING_CHARS (filename)[0] == '/');
 457       SCM_MISC_ERROR ((absolute
 458                        ? "Unable to load file ~S"
 459                        : "Unable to find file ~S in load path"),
 460                       scm_list_1 (filename));
 461     }
 462
 463   return scm_primitive_load (full_filename);
 464 }
 465 #undef FUNC_NAME
 466
 467 SCM
 468 scm_c_primitive_load_path (const char *filename)
 469 {
 470   return scm_primitive_load_path (scm_makfrom0str (filename));
 471 }
 472
 473 \f
 474 /* Information about the build environment.  */
 475
 476 /* Initialize the scheme variable %guile-build-info, based on data
 477    provided by the Makefile, via libpath.h.  */
 478 static void
 479 init_build_info ()
 480 {
 481   static struct { char *name; char *value; } info[] = SCM_BUILD_INFO;
 482   SCM *loc = SCM_VARIABLE_LOC (scm_c_define ("%guile-build-info", SCM_EOL));
 483   unsigned long i;
 484
 485   for (i = 0; i < (sizeof (info) / sizeof (info[0])); i++)
 486     *loc = scm_acons (scm_str2symbol (info[i].name),
 487                       scm_makfrom0str (info[i].value),
 488                       *loc);
 489 }
 490
 491
 492 \f
 493 void
 494 scm_init_load ()
 495 {
 496   scm_listofnullstr = scm_permanent_object (scm_list_1 (scm_nullstr));
 497   scm_loc_load_path = SCM_VARIABLE_LOC (scm_c_define ("%load-path", SCM_EOL));
 498   scm_loc_load_extensions
 499     = SCM_VARIABLE_LOC (scm_c_define ("%load-extensions",
 500                                     scm_list_2 (scm_makfrom0str (".scm"),
 501                                                 scm_nullstr)));
 502   scm_loc_load_hook = SCM_VARIABLE_LOC (scm_c_define ("%load-hook", SCM_BOOL_F));
 503
 504   init_build_info ();
 505
 506 #include "libguile/load.x"
 507 }
 508
 509 /*
 510   Local Variables:
 511   c-file-style: "gnu"
 512   End:
 513 */