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 /* 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 <string.h>
  48
  49 #include "libguile/_scm.h"
  50 #include "libguile/libpath.h"
  51 #include "libguile/fports.h"
  52 #include "libguile/read.h"
  53 #include "libguile/eval.h"
  54 #include "libguile/throw.h"
  55 #include "libguile/alist.h"
  56 #include "libguile/dynwind.h"
  57 #include "libguile/root.h"
  58 #include "libguile/strings.h"
  59 #include "libguile/modules.h"
  60
  61 #include "libguile/validate.h"
  62 #include "libguile/load.h"
  63
  64 #include <sys/types.h>
  65 #include <sys/stat.h>
  66
  67 #ifdef HAVE_UNISTD_H
  68 #include <unistd.h>
  69 #endif /* HAVE_UNISTD_H */
  70
  71 #ifndef R_OK
  72 #define R_OK 4
  73 #endif
  74
  75 \f
  76 /* Loading a file, given an absolute filename.  */
  77
  78 /* Hook to run when we load a file, perhaps to announce the fact somewhere.
  79    Applied to the full name of the file.  */
  80 static SCM *scm_loc_load_hook;
  81
  82 static void
  83 swap_port (void *data)
  84 {
  85   SCM *save_port = data, tmp = scm_cur_loadp;
  86   scm_cur_loadp = *save_port;
  87   *save_port = tmp;
  88 }
  89
  90 static SCM
  91 load (void *data)
  92 {
  93   SCM port = SCM_PACK (data);
  94   while (1)
  95     {
  96       SCM form = scm_read (port);
  97       if (SCM_EOF_OBJECT_P (form))
  98         break;
  99       scm_primitive_eval_x (form);
 100     }
 101   return SCM_UNSPECIFIED;
 102 }
 103
 104 SCM_DEFINE (scm_primitive_load, "primitive-load", 1, 0, 0,
 105            (SCM filename),
 106             "Load the file named @var{filename} and evaluate its contents in\n"
 107             "the top-level environment. The load paths are not searched;\n"
 108             "@var{filename} must either be a full pathname or be a pathname\n"
 109             "relative to the current directory.  If the  variable\n"
 110             "@code{%load-hook} is defined, it should be bound to a procedure\n"
 111             "that will be called before any code is loaded.  See the\n"
 112             "documentation for @code{%load-hook} later in this section.")
 113 #define FUNC_NAME s_scm_primitive_load
 114 {
 115   SCM hook = *scm_loc_load_hook;
 116   SCM_VALIDATE_STRING (1, filename);
 117   if (!SCM_FALSEP (hook) && !SCM_EQ_P (scm_procedure_p (hook), SCM_BOOL_T))
 118     SCM_MISC_ERROR ("value of %load-hook is neither a procedure nor #f",
 119                     SCM_EOL);
 120
 121   if (! SCM_FALSEP (hook))
 122     scm_call_1 (hook, filename);
 123
 124   { /* scope */
 125     SCM port, save_port;
 126     port = scm_open_file (filename, scm_mem2string ("r", sizeof (char)));
 127     save_port = port;
 128     scm_internal_dynamic_wind (swap_port,
 129                                load,
 130                                swap_port,
 131                                (void *) SCM_UNPACK (port),
 132                                &save_port);
 133     scm_close_port (port);
 134   }
 135   return SCM_UNSPECIFIED;
 136 }
 137 #undef FUNC_NAME
 138
 139 \f
 140 /* Builtin path to scheme library files. */
 141 #ifdef SCM_PKGDATA_DIR
 142 SCM_DEFINE (scm_sys_package_data_dir, "%package-data-dir", 0, 0, 0,
 143             (),
 144             "Return the name of the directory where Scheme packages, modules and\n"
 145             "libraries are kept.  On most Unix systems, this will be\n"
 146             "@samp{/usr/local/share/guile}.")
 147 #define FUNC_NAME s_scm_sys_package_data_dir
 148 {
 149   return scm_makfrom0str (SCM_PKGDATA_DIR);
 150 }
 151 #undef FUNC_NAME
 152 #endif /* SCM_PKGDATA_DIR */
 153
 154 #ifdef SCM_LIBRARY_DIR
 155 SCM_DEFINE (scm_sys_library_dir, "%library-dir", 0,0,0,
 156             (),
 157             "Return the directory where the Guile Scheme library files are installed.\n"
 158             "E.g., may return \"/usr/share/guile/1.3.5\".")
 159 #define FUNC_NAME s_scm_sys_library_dir
 160 {
 161   return scm_makfrom0str(SCM_LIBRARY_DIR);
 162 }
 163 #undef FUNC_NAME
 164 #endif /* SCM_LIBRARY_DIR */
 165
 166 #ifdef SCM_SITE_DIR
 167 SCM_DEFINE (scm_sys_site_dir, "%site-dir", 0,0,0,
 168             (),
 169             "Return the directory where the Guile site files are installed.\n"
 170             "E.g., may return \"/usr/share/guile/site\".")
 171 #define FUNC_NAME s_scm_sys_site_dir
 172 {
 173   return scm_makfrom0str(SCM_SITE_DIR);
 174 }
 175 #undef FUNC_NAME
 176 #endif /* SCM_SITE_DIR */
 177
 178
 179
 180 \f
 181 /* Initializing the load path, and searching it.  */
 182
 183 /* List of names of directories we search for files to load.  */
 184 static SCM *scm_loc_load_path;
 185
 186 /* List of extensions we try adding to the filenames.  */
 187 static SCM *scm_loc_load_extensions;
 188
 189
 190 /* Parse the null-terminated string PATH as if it were a standard path
 191    environment variable (i.e. a colon-separated list of strings), and
 192    prepend the elements to TAIL.  */
 193 SCM
 194 scm_internal_parse_path (char *path, SCM tail)
 195 {
 196   if (path && path[0] != '\0')
 197     {
 198       char *scan, *elt_end;
 199
 200       /* Scan backwards from the end of the string, to help
 201          construct the list in the right order.  */
 202       scan = elt_end = path + strlen (path);
 203       do {
 204         /* Scan back to the beginning of the current element.  */
 205         do scan--;
 206         while (scan >= path && *scan != ':');
 207         tail = scm_cons (scm_mem2string (scan + 1, elt_end - (scan + 1)),
 208                          tail);
 209         elt_end = scan;
 210       } while (scan >= path);
 211     }
 212
 213   return tail;
 214 }
 215
 216
 217 SCM_DEFINE (scm_parse_path, "parse-path", 1, 1, 0,
 218             (SCM path, SCM tail),
 219             "Parse @var{path}, which is expected to be a colon-separated\n"
 220             "string, into a list and return the resulting list with\n"
 221             "@var{tail} appended. If @var{path} is @code{#f}, @var{tail}\n"
 222             "is returned.")
 223 #define FUNC_NAME s_scm_parse_path
 224 {
 225   SCM_ASSERT (SCM_FALSEP (path) || (SCM_STRINGP (path)),
 226               path,
 227               SCM_ARG1, FUNC_NAME);
 228   if (SCM_UNBNDP (tail))
 229     tail = SCM_EOL;
 230   return (SCM_FALSEP (path)
 231           ? tail
 232           : scm_internal_parse_path (SCM_STRING_CHARS (path), tail));
 233 }
 234 #undef FUNC_NAME
 235
 236
 237 /* Initialize the global variable %load-path, given the value of the
 238    SCM_SITE_DIR and SCM_LIBRARY_DIR preprocessor symbols and the
 239    GUILE_LOAD_PATH environment variable.  */
 240 void
 241 scm_init_load_path ()
 242 {
 243   SCM path = SCM_EOL;
 244
 245 #ifdef SCM_LIBRARY_DIR
 246   path = scm_list_3 (scm_makfrom0str (SCM_SITE_DIR),
 247                      scm_makfrom0str (SCM_LIBRARY_DIR),
 248                      scm_makfrom0str (SCM_PKGDATA_DIR));
 249 #endif /* SCM_LIBRARY_DIR */
 250
 251   path = scm_internal_parse_path (getenv ("GUILE_LOAD_PATH"), path);
 252
 253   *scm_loc_load_path = path;
 254 }
 255
 256 SCM scm_listofnullstr;
 257
 258 /* Search PATH for a directory containing a file named FILENAME.
 259    The file must be readable, and not a directory.
 260    If we find one, return its full filename; otherwise, return #f.
 261    If FILENAME is absolute, return it unchanged.
 262    If given, EXTENSIONS is a list of strings; for each directory
 263    in PATH, we search for FILENAME concatenated with each EXTENSION.  */
 264 SCM_DEFINE (scm_search_path, "search-path", 2, 1, 0,
 265            (SCM path, SCM filename, SCM extensions),
 266             "Search @var{path} for a directory containing a file named\n"
 267             "@var{filename}. The file must be readable, and not a directory.\n"
 268             "If we find one, return its full filename; otherwise, return\n"
 269             "@code{#f}.  If @var{filename} is absolute, return it unchanged.\n"
 270             "If given, @var{extensions} is a list of strings; for each\n"
 271             "directory in @var{path}, we search for @var{filename}\n"
 272             "concatenated with each @var{extension}.")
 273 #define FUNC_NAME s_scm_search_path
 274 {
 275   char *filename_chars;
 276   int filename_len;
 277   size_t max_path_len;          /* maximum length of any PATH element */
 278   size_t max_ext_len;           /* maximum length of any EXTENSIONS element */
 279
 280   SCM_VALIDATE_LIST (1,path);
 281   SCM_VALIDATE_STRING (2, filename);
 282   if (SCM_UNBNDP (extensions))
 283     extensions = SCM_EOL;
 284   else
 285     SCM_VALIDATE_LIST (3,extensions);
 286
 287   filename_chars = SCM_STRING_CHARS (filename);
 288   filename_len = SCM_STRING_LENGTH (filename);
 289
 290   /* If FILENAME is absolute, return it unchanged.  */
 291   if (filename_len >= 1 && filename_chars[0] == '/')
 292     return filename;
 293
 294   /* Find the length of the longest element of path.  */
 295   {
 296     SCM walk;
 297
 298     max_path_len = 0;
 299     for (walk = path; !SCM_NULLP (walk); walk = SCM_CDR (walk))
 300       {
 301         SCM elt = SCM_CAR (walk);
 302         SCM_ASSERT_TYPE (SCM_STRINGP (elt), path, 1, FUNC_NAME,
 303                          "list of strings");
 304         if (SCM_STRING_LENGTH (elt) > max_path_len)
 305           max_path_len = SCM_STRING_LENGTH (elt);
 306       }
 307   }
 308
 309   /* If FILENAME has an extension, don't try to add EXTENSIONS to it.  */
 310   {
 311     char *endp;
 312
 313     for (endp = filename_chars + filename_len - 1;
 314          endp >= filename_chars;
 315          endp--)
 316       {
 317         if (*endp == '.')
 318           {
 319             /* This filename already has an extension, so cancel the
 320                list of extensions.  */
 321             extensions = SCM_EOL;
 322             break;
 323           }
 324         else if (*endp == '/')
 325           /* This filename has no extension, so keep the current list
 326              of extensions.  */
 327           break;
 328       }
 329   }
 330
 331   /* Find the length of the longest element of the load extensions
 332      list.  */
 333   { /* scope */
 334     SCM walk;
 335
 336     max_ext_len = 0;
 337     for (walk = extensions; !SCM_NULLP (walk); walk = SCM_CDR (walk))
 338       {
 339         SCM elt = SCM_CAR (walk);
 340         SCM_ASSERT_TYPE (SCM_STRINGP (elt), elt, 3, FUNC_NAME,
 341                          "list of strings");
 342         if (SCM_STRING_LENGTH (elt) > max_ext_len)
 343           max_ext_len = SCM_STRING_LENGTH (elt);
 344       }
 345   }
 346
 347   SCM_DEFER_INTS;
 348
 349   { /* scope */
 350     SCM result = SCM_BOOL_F;
 351     size_t buf_size = max_path_len + 1 + filename_len + max_ext_len + 1;
 352     char *buf = SCM_MUST_MALLOC (buf_size);
 353
 354     /* This simplifies the loop below a bit.  */
 355     if (SCM_NULLP (extensions))
 356       extensions = scm_listofnullstr;
 357
 358     /* Try every path element.  At this point, we know the path is a
 359        proper list of strings.  */
 360     for (; !SCM_NULLP (path); path = SCM_CDR (path))
 361       {
 362         size_t len;
 363         SCM dir = SCM_CAR (path);
 364         SCM exts;
 365
 366         /* Concatenate the path name and the filename. */
 367         len = SCM_STRING_LENGTH (dir);
 368         memcpy (buf, SCM_STRING_CHARS (dir), len);
 369         if (len >= 1 && buf[len - 1] != '/')
 370           buf[len++] = '/';
 371         memcpy (buf + len, filename_chars, filename_len);
 372         len += filename_len;
 373
 374         /* Try every extension.  At this point, we know the extension
 375            list is a proper, nonempty list of strings.  */
 376         for (exts = extensions; !SCM_NULLP (exts); exts = SCM_CDR (exts))
 377           {
 378             SCM ext = SCM_CAR (exts);
 379             size_t ext_len = SCM_STRING_LENGTH (ext);
 380             struct stat mode;
 381
 382             /* Concatenate the extension. */
 383             memcpy (buf + len, SCM_STRING_CHARS (ext), ext_len);
 384             buf[len + ext_len] = '\0';
 385
 386             /* If the file exists at all, we should return it.  If the
 387                file is inaccessible, then that's an error.  */
 388             if (stat (buf, &mode) == 0
 389                 && ! (mode.st_mode & S_IFDIR))
 390               {
 391                 result = scm_mem2string (buf, len + ext_len);
 392                 goto end;
 393               }
 394           }
 395       }
 396
 397   end:
 398     scm_must_free (buf);
 399     scm_done_free (buf_size);
 400     SCM_ALLOW_INTS;
 401     return result;
 402   }
 403 }
 404 #undef FUNC_NAME
 405
 406
 407 /* Search %load-path for a directory containing a file named FILENAME.
 408    The file must be readable, and not a directory.
 409    If we find one, return its full filename; otherwise, return #f.
 410    If FILENAME is absolute, return it unchanged.  */
 411 SCM_DEFINE (scm_sys_search_load_path, "%search-load-path", 1, 0, 0,
 412             (SCM filename),
 413             "Search @var{%load-path} for the file named @var{filename},\n"
 414             "which must be readable by the current user.  If @var{filename}\n"
 415             "is found in the list of paths to search or is an absolute\n"
 416             "pathname, return its full pathname.  Otherwise, return\n"
 417             "@code{#f}.  Filenames may have any of the optional extensions\n"
 418             "in the @code{%load-extensions} list; @code{%search-load-path}\n"
 419             "will try each extension automatically.")
 420 #define FUNC_NAME s_scm_sys_search_load_path
 421 {
 422   SCM path = *scm_loc_load_path;
 423   SCM exts = *scm_loc_load_extensions;
 424   SCM_VALIDATE_STRING (1, filename);
 425
 426   if (scm_ilength (path) < 0)
 427     SCM_MISC_ERROR ("%load-path is not a proper list", SCM_EOL);
 428   if (scm_ilength (exts) < 0)
 429     SCM_MISC_ERROR ("%load-extension list is not a proper list", SCM_EOL);
 430   return scm_search_path (path, filename, exts);
 431 }
 432 #undef FUNC_NAME
 433
 434
 435 SCM_DEFINE (scm_primitive_load_path, "primitive-load-path", 1, 0, 0,
 436             (SCM filename),
 437             "Search @var{%load-path} for the file named @var{filename} and\n"
 438             "load it into the top-level environment.  If @var{filename} is a\n"
 439             "relative pathname and is not found in the list of search paths,\n"
 440             "an error is signalled.")
 441 #define FUNC_NAME s_scm_primitive_load_path
 442 {
 443   SCM full_filename;
 444
 445   SCM_VALIDATE_STRING (1, filename);
 446
 447   full_filename = scm_sys_search_load_path (filename);
 448
 449   if (SCM_FALSEP (full_filename))
 450     {
 451       int absolute = (SCM_STRING_LENGTH (filename) >= 1
 452                       && SCM_STRING_CHARS (filename)[0] == '/');
 453       SCM_MISC_ERROR ((absolute
 454                        ? "Unable to load file ~S"
 455                        : "Unable to find file ~S in load path"),
 456                       scm_list_1 (filename));
 457     }
 458
 459   return scm_primitive_load (full_filename);
 460 }
 461 #undef FUNC_NAME
 462
 463 #if SCM_DEBUG_DEPRECATED == 0
 464
 465 /* Eval now copies source properties, so this function is no longer required.
 466  */
 467
 468 SCM_SYMBOL (scm_end_of_file_key, "end-of-file");
 469
 470 SCM_DEFINE (scm_read_and_eval_x, "read-and-eval!", 0, 1, 0,
 471             (SCM port),
 472             "Read a form from @var{port} (standard input by default), and evaluate it\n"
 473             "(memoizing it in the process) in the top-level environment.  If no data\n"
 474             "is left to be read from @var{port}, an @code{end-of-file} error is\n"
 475             "signalled.")
 476 #define FUNC_NAME s_scm_read_and_eval_x
 477 {
 478   SCM form = scm_read (port);
 479   if (SCM_EOF_OBJECT_P (form))
 480     scm_ithrow (scm_end_of_file_key, SCM_EOL, 1);
 481   return scm_eval_x (form, scm_current_module ());
 482 }
 483 #undef FUNC_NAME
 484
 485 #endif
 486
 487 \f
 488 /* Information about the build environment.  */
 489
 490 /* Initialize the scheme variable %guile-build-info, based on data
 491    provided by the Makefile, via libpath.h.  */
 492 static void
 493 init_build_info ()
 494 {
 495   static struct { char *name; char *value; } info[] = SCM_BUILD_INFO;
 496   SCM *loc = SCM_VARIABLE_LOC (scm_c_define ("%guile-build-info", SCM_EOL));
 497   unsigned long i;
 498
 499   for (i = 0; i < (sizeof (info) / sizeof (info[0])); i++)
 500     *loc = scm_acons (scm_str2symbol (info[i].name),
 501                       scm_makfrom0str (info[i].value),
 502                       *loc);
 503 }
 504
 505
 506 \f
 507 void
 508 scm_init_load ()
 509 {
 510   scm_listofnullstr = scm_permanent_object (scm_list_1 (scm_nullstr));
 511   scm_loc_load_path = SCM_VARIABLE_LOC (scm_c_define ("%load-path", SCM_EOL));
 512   scm_loc_load_extensions
 513     = SCM_VARIABLE_LOC (scm_c_define ("%load-extensions",
 514                                     scm_list_2 (scm_makfrom0str (".scm"),
 515                                                 scm_nullstr)));
 516   scm_loc_load_hook = SCM_VARIABLE_LOC (scm_c_define ("%load-hook", SCM_BOOL_F));
 517
 518   init_build_info ();
 519
 520 #ifndef SCM_MAGIC_SNARFER
 521 #include "libguile/load.x"
 522 #endif
 523 }
 524
 525 /*
 526   Local Variables:
 527   c-file-style: "gnu"
 528   End:
 529 */