libguile/load.c

   1 /*      Copyright (C) 1995,1996,1998,1999, 2000 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 #include "libguile/modules.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       /* Ugh!  We need to re-check the environment for every form.
  99        * We should change this in the new module system.
 100        */
 101       scm_i_eval_x (form,
 102                     scm_module_system_booted_p
 103                     ? (scm_top_level_env
 104                        (SCM_MODULE_EVAL_CLOSURE (scm_selected_module ())))
 105                     : SCM_EOL);
 106     }
 107   return SCM_UNSPECIFIED;
 108 }
 109
 110 SCM_DEFINE (scm_primitive_load, "primitive-load", 1, 0, 0,
 111            (SCM filename),
 112             "Load @var{file} and evaluate its contents in the top-level environment.\n"
 113             "The load paths are not searched; @var{file} must either be a full\n"
 114             "pathname or be a pathname relative to the current directory.  If the\n"
 115             "variable @code{%load-hook} is defined, it should be bound to a procedure\n"
 116             "that will be called before any code is loaded.  See documentation for\n"
 117             "@code{%load-hook} later in this section.")
 118 #define FUNC_NAME s_scm_primitive_load
 119 {
 120   SCM hook = *scm_loc_load_hook;
 121   SCM_VALIDATE_ROSTRING (1,filename);
 122   SCM_ASSERT (SCM_FALSEP (hook) || (SCM_EQ_P (scm_procedure_p (hook), SCM_BOOL_T)),
 123               hook, "value of %load-hook is neither a procedure nor #f",
 124               FUNC_NAME);
 125
 126   if (! SCM_FALSEP (hook))
 127     scm_apply (hook, scm_listify (filename, SCM_UNDEFINED), SCM_EOL);
 128
 129   { /* scope */
 130     SCM port, save_port;
 131     port = scm_open_file (filename,
 132                           scm_makfromstr ("r", (scm_sizet) sizeof (char), 0));
 133     save_port = port;
 134     scm_internal_dynamic_wind (swap_port,
 135                                load,
 136                                swap_port,
 137                                (void *) SCM_UNPACK (port),
 138                                &save_port);
 139     scm_close_port (port);
 140   }
 141   return SCM_UNSPECIFIED;
 142 }
 143 #undef FUNC_NAME
 144
 145 \f
 146 /* Builtin path to scheme library files. */
 147 #ifdef SCM_PKGDATA_DIR
 148 SCM_DEFINE (scm_sys_package_data_dir, "%package-data-dir", 0, 0, 0,
 149             (),
 150             "Return the name of the directory where Scheme packages, modules and\n"
 151             "libraries are kept.  On most Unix systems, this will be\n"
 152             "@samp{/usr/local/share/guile}.")
 153 #define FUNC_NAME s_scm_sys_package_data_dir
 154 {
 155   return scm_makfrom0str (SCM_PKGDATA_DIR);
 156 }
 157 #undef FUNC_NAME
 158 #endif /* SCM_PKGDATA_DIR */
 159
 160 #ifdef SCM_LIBRARY_DIR
 161 SCM_DEFINE (scm_sys_library_dir, "%library-dir", 0,0,0,
 162             (),
 163             "Return the directory where the Guile Scheme library files are installed.\n"
 164             "E.g., may return \"/usr/share/guile/1.3.5\".")
 165 #define FUNC_NAME s_scm_sys_library_dir
 166 {
 167   return scm_makfrom0str(SCM_LIBRARY_DIR);
 168 }
 169 #undef FUNC_NAME
 170 #endif /* SCM_LIBRARY_DIR */
 171
 172 #ifdef SCM_SITE_DIR
 173 SCM_DEFINE (scm_sys_site_dir, "%site-dir", 0,0,0,
 174             (),
 175             "Return the directory where the Guile site files are installed.\n"
 176             "E.g., may return \"/usr/share/guile/site\".")
 177 #define FUNC_NAME s_scm_sys_site_dir
 178 {
 179   return scm_makfrom0str(SCM_SITE_DIR);
 180 }
 181 #undef FUNC_NAME
 182 #endif /* SCM_SITE_DIR */
 183
 184
 185
 186 \f
 187 /* Initializing the load path, and searching it.  */
 188
 189 /* List of names of directories we search for files to load.  */
 190 static SCM *scm_loc_load_path;
 191
 192 /* List of extensions we try adding to the filenames.  */
 193 static SCM *scm_loc_load_extensions;
 194
 195
 196 /* Parse the null-terminated string PATH as if it were a standard path
 197    environment variable (i.e. a colon-separated list of strings), and
 198    prepend the elements to TAIL.  */
 199 SCM
 200 scm_internal_parse_path (char *path, SCM tail)
 201 {
 202   if (path && path[0] != '\0')
 203     {
 204       char *scan, *elt_end;
 205
 206       /* Scan backwards from the end of the string, to help
 207          construct the list in the right order.  */
 208       scan = elt_end = path + strlen (path);
 209       do {
 210         /* Scan back to the beginning of the current element.  */
 211         do scan--;
 212         while (scan >= path && *scan != ':');
 213         tail = scm_cons (scm_makfromstr (scan + 1, elt_end - (scan + 1), 0),
 214                          tail);
 215         elt_end = scan;
 216       } while (scan >= path);
 217     }
 218
 219   return tail;
 220 }
 221
 222
 223 SCM_DEFINE (scm_parse_path, "parse-path", 1, 1, 0,
 224             (SCM path, SCM tail),
 225             "")
 226 #define FUNC_NAME s_scm_parse_path
 227 {
 228   SCM_ASSERT (SCM_FALSEP (path) || (SCM_ROSTRINGP (path)),
 229               path,
 230               SCM_ARG1, FUNC_NAME);
 231   if (SCM_UNBNDP (tail))
 232     tail = SCM_EOL;
 233   return (SCM_FALSEP (path)
 234           ? tail
 235           : scm_internal_parse_path (SCM_ROCHARS (path), tail));
 236 }
 237 #undef FUNC_NAME
 238
 239
 240 /* Initialize the global variable %load-path, given the value of the
 241    SCM_SITE_DIR and SCM_LIBRARY_DIR preprocessor symbols and the
 242    GUILE_LOAD_PATH environment variable.  */
 243 void
 244 scm_init_load_path ()
 245 {
 246   SCM path = SCM_EOL;
 247
 248 #ifdef SCM_LIBRARY_DIR
 249   path = scm_listify (scm_makfrom0str (SCM_SITE_DIR),
 250                       scm_makfrom0str (SCM_LIBRARY_DIR),
 251                       scm_makfrom0str (SCM_PKGDATA_DIR),
 252                       SCM_UNDEFINED);
 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             "")
 271 #define FUNC_NAME s_scm_search_path
 272 {
 273   char *filename_chars;
 274   int filename_len;
 275   size_t max_path_len;          /* maximum length of any PATH element */
 276   size_t max_ext_len;           /* maximum length of any EXTENSIONS element */
 277
 278   SCM_VALIDATE_LIST (1,path);
 279   SCM_VALIDATE_ROSTRING (2,filename);
 280   if (SCM_UNBNDP (extensions))
 281     extensions = SCM_EOL;
 282   else
 283     SCM_VALIDATE_LIST (3,extensions);
 284
 285   filename_chars = SCM_ROCHARS (filename);
 286   filename_len = SCM_ROLENGTH (filename);
 287
 288   /* If FILENAME is absolute, return it unchanged.  */
 289   if (filename_len >= 1 && filename_chars[0] == '/')
 290     return filename;
 291
 292   /* Find the length of the longest element of path.  */
 293   {
 294     SCM walk;
 295
 296     max_path_len = 0;
 297     for (walk = path; SCM_NNULLP (walk); walk = SCM_CDR (walk))
 298       {
 299         SCM elt = SCM_CAR (walk);
 300         SCM_ASSERT (SCM_ROSTRINGP (elt), elt,
 301                     "path is not a list of strings",
 302                     FUNC_NAME);
 303         if (SCM_ROLENGTH (elt) > max_path_len)
 304           max_path_len = SCM_ROLENGTH (elt);
 305       }
 306   }
 307
 308   /* If FILENAME has an extension, don't try to add EXTENSIONS to it.  */
 309   {
 310     char *endp;
 311
 312     for (endp = filename_chars + filename_len - 1;
 313          endp >= filename_chars;
 314          endp--)
 315       {
 316         if (*endp == '.')
 317           {
 318             /* This filename already has an extension, so cancel the
 319                list of extensions.  */
 320             extensions = SCM_EOL;
 321             break;
 322           }
 323         else if (*endp == '/')
 324           /* This filename has no extension, so keep the current list
 325              of extensions.  */
 326           break;
 327       }
 328   }
 329
 330   /* Find the length of the longest element of the load extensions
 331      list.  */
 332   { /* scope */
 333     SCM walk;
 334
 335     max_ext_len = 0;
 336     for (walk = extensions; SCM_NNULLP (walk); walk = SCM_CDR (walk))
 337       {
 338         SCM elt = SCM_CAR (walk);
 339         SCM_ASSERT (SCM_ROSTRINGP (elt), elt,
 340                     "extension list is not a list of strings",
 341                     FUNC_NAME);
 342         if (SCM_ROLENGTH (elt) > max_ext_len)
 343           max_ext_len = SCM_ROLENGTH (elt);
 344       }
 345   }
 346
 347   SCM_DEFER_INTS;
 348
 349   { /* scope */
 350     SCM result = SCM_BOOL_F;
 351     int 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_NNULLP (path); path = SCM_CDR (path))
 361       {
 362         int len;
 363         SCM dir = SCM_CAR (path);
 364         SCM exts;
 365
 366         /* Concatenate the path name and the filename. */
 367         len = SCM_ROLENGTH (dir);
 368         memcpy (buf, SCM_ROCHARS (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_NNULLP (exts); exts = SCM_CDR (exts))
 377           {
 378             SCM ext = SCM_CAR (exts);
 379             int ext_len = SCM_ROLENGTH (ext);
 380             struct stat mode;
 381
 382             /* Concatenate the extension. */
 383             memcpy (buf + len, SCM_ROCHARS (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_makfromstr (buf, len + ext_len, 0);
 392                 goto end;
 393               }
 394           }
 395       }
 396
 397   end:
 398     scm_must_free (buf);
 399     scm_done_malloc (- 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 @var{file}, which must be readable by the\n"
 414             "current user.  If @var{file} is found in the list of paths to search or\n"
 415             "is an absolute pathname, return its full pathname.  Otherwise, return\n"
 416             "@code{#f}.  Filenames may have any of the optional extensions in the\n"
 417             "@code{%load-extensions} list; @code{%search-load-path} will try each\n"
 418             "extension automatically.")
 419 #define FUNC_NAME s_scm_sys_search_load_path
 420 {
 421   SCM path = *scm_loc_load_path;
 422   SCM exts = *scm_loc_load_extensions;
 423   SCM_VALIDATE_ROSTRING (1,filename);
 424
 425   SCM_ASSERT (scm_ilength (path) >= 0, path, "load path is not a proper list",
 426               FUNC_NAME);
 427   SCM_ASSERT (scm_ilength (exts) >= 0, exts,
 428               "load extension list is not a proper list",
 429               FUNC_NAME);
 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 @var{file} and load it into the top-level\n"
 438             "environment.  If @var{file} is a relative pathname and is not found in\n"
 439             "the list of search paths, an error is signalled.")
 440 #define FUNC_NAME s_scm_primitive_load_path
 441 {
 442   SCM full_filename;
 443
 444   SCM_VALIDATE_ROSTRING (1,filename);
 445
 446   full_filename = scm_sys_search_load_path (filename);
 447
 448   if (SCM_FALSEP (full_filename))
 449     {
 450       int absolute = (SCM_ROLENGTH (filename) >= 1
 451                       && SCM_ROCHARS (filename)[0] == '/');
 452       SCM_MISC_ERROR ((absolute
 453                        ? "Unable to load file ~S"
 454                        : "Unable to find file ~S in load path"),
 455                       scm_listify (filename, SCM_UNDEFINED));
 456     }
 457
 458   return scm_primitive_load (full_filename);
 459 }
 460 #undef FUNC_NAME
 461
 462 #if SCM_DEBUG_DEPRECATED == 0
 463
 464 /* Eval now copies source properties, so this function is no longer required.
 465  */
 466
 467 SCM_SYMBOL (scm_end_of_file_key, "end-of-file");
 468
 469 SCM_DEFINE (scm_read_and_eval_x, "read-and-eval!", 0, 1, 0,
 470             (SCM port),
 471             "Read a form from @var{port} (standard input by default), and evaluate it\n"
 472             "(memoizing it in the process) in the top-level environment.  If no data\n"
 473             "is left to be read from @var{port}, an @code{end-of-file} error is\n"
 474             "signalled.")
 475 #define FUNC_NAME s_scm_read_and_eval_x
 476 {
 477   SCM form = scm_read (port);
 478   if (SCM_EOF_OBJECT_P (form))
 479     scm_ithrow (scm_end_of_file_key, SCM_EOL, 1);
 480   return scm_eval_x (form, scm_selected_module ());
 481 }
 482 #undef FUNC_NAME
 483
 484 #endif
 485
 486 \f
 487 /* Information about the build environment.  */
 488
 489 /* Initialize the scheme variable %guile-build-info, based on data
 490    provided by the Makefile, via libpath.h.  */
 491 static void
 492 init_build_info ()
 493 {
 494   static struct { char *name; char *value; } info[] = SCM_BUILD_INFO;
 495   SCM *loc = SCM_CDRLOC (scm_sysintern ("%guile-build-info", SCM_EOL));
 496   unsigned int i;
 497
 498   for (i = 0; i < (sizeof (info) / sizeof (info[0])); i++)
 499     *loc = scm_acons (SCM_CAR (scm_intern0 (info[i].name)),
 500                       scm_makfrom0str (info[i].value),
 501                       *loc);
 502 }
 503
 504
 505 \f
 506 void
 507 scm_init_load ()
 508 {
 509   scm_listofnullstr = scm_permanent_object (SCM_LIST1 (scm_nullstr));
 510   scm_loc_load_path = SCM_CDRLOC (scm_sysintern ("%load-path", SCM_EOL));
 511   scm_loc_load_extensions
 512     = SCM_CDRLOC (scm_sysintern ("%load-extensions",
 513                                  scm_listify (scm_makfrom0str (".scm"),
 514                                               scm_makfrom0str (""),
 515                                               SCM_UNDEFINED)));
 516   scm_loc_load_hook = SCM_CDRLOC (scm_sysintern ("%load-hook", SCM_BOOL_F));
 517
 518   init_build_info ();
 519
 520 #include "libguile/load.x"
 521 }
 522
 523 /*
 524   Local Variables:
 525   c-file-style: "gnu"
 526   End:
 527 */