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
  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_primitive_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 the file named @var{filename} and evaluate its contents in\n"
 105             "the top-level environment. The load paths are not searched;\n"
 106             "@var{filename} must either be a full pathname or be a pathname\n"
 107             "relative to the current directory.  If the  variable\n"
 108             "@code{%load-hook} is defined, it should be bound to a procedure\n"
 109             "that will be called before any code is loaded.  See the\n"
 110             "documentation for @code{%load-hook} later in this section.")
 111 #define FUNC_NAME s_scm_primitive_load
 112 {
 113   SCM hook = *scm_loc_load_hook;
 114   SCM_VALIDATE_STRING (1, filename);
 115   if (!SCM_FALSEP (hook) && !SCM_EQ_P (scm_procedure_p (hook), SCM_BOOL_T))
 116     SCM_MISC_ERROR ("value of %load-hook is neither a procedure nor #f",
 117                     SCM_EOL);
 118
 119   if (! SCM_FALSEP (hook))
 120     scm_call_1 (hook, filename);
 121
 122   { /* scope */
 123     SCM port, save_port;
 124     port = scm_open_file (filename, scm_mem2string ("r", sizeof (char)));
 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 SCM
 138 scm_c_primitive_load (const char *filename)
 139 {
 140   return scm_primitive_load (scm_makfrom0str (filename));
 141 }
 142
 143 \f
 144 /* Builtin path to scheme library files. */
 145 #ifdef SCM_PKGDATA_DIR
 146 SCM_DEFINE (scm_sys_package_data_dir, "%package-data-dir", 0, 0, 0,
 147             (),
 148             "Return the name of the directory where Scheme packages, modules and\n"
 149             "libraries are kept.  On most Unix systems, this will be\n"
 150             "@samp{/usr/local/share/guile}.")
 151 #define FUNC_NAME s_scm_sys_package_data_dir
 152 {
 153   return scm_makfrom0str (SCM_PKGDATA_DIR);
 154 }
 155 #undef FUNC_NAME
 156 #endif /* SCM_PKGDATA_DIR */
 157
 158 #ifdef SCM_LIBRARY_DIR
 159 SCM_DEFINE (scm_sys_library_dir, "%library-dir", 0,0,0,
 160             (),
 161             "Return the directory where the Guile Scheme library files are installed.\n"
 162             "E.g., may return \"/usr/share/guile/1.3.5\".")
 163 #define FUNC_NAME s_scm_sys_library_dir
 164 {
 165   return scm_makfrom0str(SCM_LIBRARY_DIR);
 166 }
 167 #undef FUNC_NAME
 168 #endif /* SCM_LIBRARY_DIR */
 169
 170 #ifdef SCM_SITE_DIR
 171 SCM_DEFINE (scm_sys_site_dir, "%site-dir", 0,0,0,
 172             (),
 173             "Return the directory where the Guile site files are installed.\n"
 174             "E.g., may return \"/usr/share/guile/site\".")
 175 #define FUNC_NAME s_scm_sys_site_dir
 176 {
 177   return scm_makfrom0str(SCM_SITE_DIR);
 178 }
 179 #undef FUNC_NAME
 180 #endif /* SCM_SITE_DIR */
 181
 182
 183
 184 \f
 185 /* Initializing the load path, and searching it.  */
 186
 187 /* List of names of directories we search for files to load.  */
 188 static SCM *scm_loc_load_path;
 189
 190 /* List of extensions we try adding to the filenames.  */
 191 static SCM *scm_loc_load_extensions;
 192
 193
 194 /* Parse the null-terminated string PATH as if it were a standard path
 195    environment variable (i.e. a colon-separated list of strings), and
 196    prepend the elements to TAIL.  */
 197 SCM
 198 scm_internal_parse_path (char *path, SCM tail)
 199 {
 200   if (path && path[0] != '\0')
 201     {
 202       char *scan, *elt_end;
 203
 204       /* Scan backwards from the end of the string, to help
 205          construct the list in the right order.  */
 206       scan = elt_end = path + strlen (path);
 207       do {
 208         /* Scan back to the beginning of the current element.  */
 209         do scan--;
 210         while (scan >= path && *scan != ':');
 211         tail = scm_cons (scm_mem2string (scan + 1, elt_end - (scan + 1)),
 212                          tail);
 213         elt_end = scan;
 214       } while (scan >= path);
 215     }
 216
 217   return tail;
 218 }
 219
 220
 221 SCM_DEFINE (scm_parse_path, "parse-path", 1, 1, 0,
 222             (SCM path, SCM tail),
 223             "Parse @var{path}, which is expected to be a colon-separated\n"
 224             "string, into a list and return the resulting list with\n"
 225             "@var{tail} appended. If @var{path} is @code{#f}, @var{tail}\n"
 226             "is returned.")
 227 #define FUNC_NAME s_scm_parse_path
 228 {
 229   SCM_ASSERT (SCM_FALSEP (path) || (SCM_STRINGP (path)),
 230               path,
 231               SCM_ARG1, FUNC_NAME);
 232   if (SCM_UNBNDP (tail))
 233     tail = SCM_EOL;
 234   return (SCM_FALSEP (path)
 235           ? tail
 236           : scm_internal_parse_path (SCM_STRING_CHARS (path), tail));
 237 }
 238 #undef FUNC_NAME
 239
 240
 241 /* Initialize the global variable %load-path, given the value of the
 242    SCM_SITE_DIR and SCM_LIBRARY_DIR preprocessor symbols and the
 243    GUILE_LOAD_PATH environment variable.  */
 244 void
 245 scm_init_load_path ()
 246 {
 247   SCM path = SCM_EOL;
 248
 249 #ifdef SCM_LIBRARY_DIR
 250   path = scm_list_3 (scm_makfrom0str (SCM_SITE_DIR),
 251                      scm_makfrom0str (SCM_LIBRARY_DIR),
 252                      scm_makfrom0str (SCM_PKGDATA_DIR));
 253 #endif /* SCM_LIBRARY_DIR */
 254
 255   path = scm_internal_parse_path (getenv ("GUILE_LOAD_PATH"), path);
 256
 257   *scm_loc_load_path = path;
 258 }
 259
 260 SCM scm_listofnullstr;
 261
 262 /* Search PATH for a directory containing a file named FILENAME.
 263    The file must be readable, and not a directory.
 264    If we find one, return its full filename; otherwise, return #f.
 265    If FILENAME is absolute, return it unchanged.
 266    If given, EXTENSIONS is a list of strings; for each directory
 267    in PATH, we search for FILENAME concatenated with each EXTENSION.  */
 268 SCM_DEFINE (scm_search_path, "search-path", 2, 1, 0,
 269            (SCM path, SCM filename, SCM extensions),
 270             "Search @var{path} for a directory containing a file named\n"
 271             "@var{filename}. The file must be readable, and not a directory.\n"
 272             "If we find one, return its full filename; otherwise, return\n"
 273             "@code{#f}.  If @var{filename} is absolute, return it unchanged.\n"
 274             "If given, @var{extensions} is a list of strings; for each\n"
 275             "directory in @var{path}, we search for @var{filename}\n"
 276             "concatenated with each @var{extension}.")
 277 #define FUNC_NAME s_scm_search_path
 278 {
 279   char *filename_chars;
 280   int filename_len;
 281   size_t max_path_len;          /* maximum length of any PATH element */
 282   size_t max_ext_len;           /* maximum length of any EXTENSIONS element */
 283
 284   SCM_VALIDATE_LIST (1,path);
 285   SCM_VALIDATE_STRING (2, filename);
 286   if (SCM_UNBNDP (extensions))
 287     extensions = SCM_EOL;
 288   else
 289     SCM_VALIDATE_LIST (3,extensions);
 290
 291   filename_chars = SCM_STRING_CHARS (filename);
 292   filename_len = SCM_STRING_LENGTH (filename);
 293
 294   /* If FILENAME is absolute, return it unchanged.  */
 295   if (filename_len >= 1 && filename_chars[0] == '/')
 296     return filename;
 297
 298   /* Find the length of the longest element of path.  */
 299   {
 300     SCM walk;
 301
 302     max_path_len = 0;
 303     for (walk = path; !SCM_NULLP (walk); walk = SCM_CDR (walk))
 304       {
 305         SCM elt = SCM_CAR (walk);
 306         SCM_ASSERT_TYPE (SCM_STRINGP (elt), path, 1, FUNC_NAME,
 307                          "list of strings");
 308         if (SCM_STRING_LENGTH (elt) > max_path_len)
 309           max_path_len = SCM_STRING_LENGTH (elt);
 310       }
 311   }
 312
 313   /* If FILENAME has an extension, don't try to add EXTENSIONS to it.  */
 314   {
 315     char *endp;
 316
 317     for (endp = filename_chars + filename_len - 1;
 318          endp >= filename_chars;
 319          endp--)
 320       {
 321         if (*endp == '.')
 322           {
 323             /* This filename already has an extension, so cancel the
 324                list of extensions.  */
 325             extensions = SCM_EOL;
 326             break;
 327           }
 328         else if (*endp == '/')
 329           /* This filename has no extension, so keep the current list
 330              of extensions.  */
 331           break;
 332       }
 333   }
 334
 335   /* Find the length of the longest element of the load extensions
 336      list.  */
 337   { /* scope */
 338     SCM walk;
 339
 340     max_ext_len = 0;
 341     for (walk = extensions; !SCM_NULLP (walk); walk = SCM_CDR (walk))
 342       {
 343         SCM elt = SCM_CAR (walk);
 344         SCM_ASSERT_TYPE (SCM_STRINGP (elt), elt, 3, FUNC_NAME,
 345                          "list of strings");
 346         if (SCM_STRING_LENGTH (elt) > max_ext_len)
 347           max_ext_len = SCM_STRING_LENGTH (elt);
 348       }
 349   }
 350
 351   SCM_DEFER_INTS;
 352
 353   { /* scope */
 354     SCM result = SCM_BOOL_F;
 355     size_t buf_size = max_path_len + 1 + filename_len + max_ext_len + 1;
 356     char *buf = SCM_MUST_MALLOC (buf_size);
 357
 358     /* This simplifies the loop below a bit.  */
 359     if (SCM_NULLP (extensions))
 360       extensions = scm_listofnullstr;
 361
 362     /* Try every path element.  At this point, we know the path is a
 363        proper list of strings.  */
 364     for (; !SCM_NULLP (path); path = SCM_CDR (path))
 365       {
 366         size_t len;
 367         SCM dir = SCM_CAR (path);
 368         SCM exts;
 369
 370         /* Concatenate the path name and the filename. */
 371         len = SCM_STRING_LENGTH (dir);
 372         memcpy (buf, SCM_STRING_CHARS (dir), len);
 373         if (len >= 1 && buf[len - 1] != '/')
 374           buf[len++] = '/';
 375         memcpy (buf + len, filename_chars, filename_len);
 376         len += filename_len;
 377
 378         /* Try every extension.  At this point, we know the extension
 379            list is a proper, nonempty list of strings.  */
 380         for (exts = extensions; !SCM_NULLP (exts); exts = SCM_CDR (exts))
 381           {
 382             SCM ext = SCM_CAR (exts);
 383             size_t ext_len = SCM_STRING_LENGTH (ext);
 384             struct stat mode;
 385
 386             /* Concatenate the extension. */
 387             memcpy (buf + len, SCM_STRING_CHARS (ext), ext_len);
 388             buf[len + ext_len] = '\0';
 389
 390             /* If the file exists at all, we should return it.  If the
 391                file is inaccessible, then that's an error.  */
 392             if (stat (buf, &mode) == 0
 393                 && ! (mode.st_mode & S_IFDIR))
 394               {
 395                 result = scm_mem2string (buf, len + ext_len);
 396                 goto end;
 397               }
 398           }
 399       }
 400
 401   end:
 402     scm_must_free (buf);
 403     scm_done_free (buf_size);
 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 #ifndef SCM_MAGIC_SNARFER
 507 #include "libguile/load.x"
 508 #endif
 509 }
 510
 511 /*
 512   Local Variables:
 513   c-file-style: "gnu"
 514   End:
 515 */