libguile/ioext.c

   1 /*      Copyright (C) 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2003 Free Software Foundation, Inc.
   2  *
   3  * This library is free software; you can redistribute it and/or
   4  * modify it under the terms of the GNU Lesser General Public
   5  * License as published by the Free Software Foundation; either
   6  * version 2.1 of the License, or (at your option) any later version.
   7  *
   8  * This library 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 GNU
  11  * Lesser General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU Lesser General Public
  14  * License along with this library; if not, write to the Free Software
  15  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  16  */
  17
  18
  19 \f
  20
  21 #if HAVE_CONFIG_H
  22 #  include <config.h>
  23 #endif
  24
  25 #include <stdio.h>
  26 #include <errno.h>
  27
  28 #include "libguile/_scm.h"
  29 #include "libguile/ioext.h"
  30 #include "libguile/fports.h"
  31 #include "libguile/feature.h"
  32 #include "libguile/ports.h"
  33 #include "libguile/strings.h"
  34 #include "libguile/validate.h"
  35
  36 #include <fcntl.h>
  37
  38 #ifdef HAVE_IO_H
  39 #include <io.h>
  40 #endif
  41 #ifdef HAVE_UNISTD_H
  42 #include <unistd.h>
  43 #endif
  44 \f
  45
  46 SCM_DEFINE (scm_ftell, "ftell", 1, 0, 0,
  47             (SCM fd_port),
  48             "Return an integer representing the current position of\n"
  49             "@var{fd/port}, measured from the beginning.  Equivalent to:\n"
  50             "\n"
  51             "@lisp\n"
  52             "(seek port 0 SEEK_CUR)\n"
  53             "@end lisp")
  54 #define FUNC_NAME s_scm_ftell
  55 {
  56   return scm_seek (fd_port, SCM_INUM0, SCM_I_MAKINUM (SEEK_CUR));
  57 }
  58 #undef FUNC_NAME
  59
  60 SCM_DEFINE (scm_redirect_port, "redirect-port", 2, 0, 0,
  61             (SCM old, SCM new),
  62             "This procedure takes two ports and duplicates the underlying file\n"
  63             "descriptor from @var{old-port} into @var{new-port}.  The\n"
  64             "current file descriptor in @var{new-port} will be closed.\n"
  65             "After the redirection the two ports will share a file position\n"
  66             "and file status flags.\n\n"
  67             "The return value is unspecified.\n\n"
  68             "Unexpected behaviour can result if both ports are subsequently used\n"
  69             "and the original and/or duplicate ports are buffered.\n\n"
  70             "This procedure does not have any side effects on other ports or\n"
  71             "revealed counts.")
  72 #define FUNC_NAME s_scm_redirect_port
  73 {
  74   int ans, oldfd, newfd;
  75   scm_t_fport *fp;
  76
  77   old = SCM_COERCE_OUTPORT (old);
  78   new = SCM_COERCE_OUTPORT (new);
  79
  80   SCM_VALIDATE_OPFPORT (1, old);
  81   SCM_VALIDATE_OPFPORT (2, new);
  82   oldfd = SCM_FPORT_FDES (old);
  83   fp = SCM_FSTREAM (new);
  84   newfd = fp->fdes;
  85   if (oldfd != newfd)
  86     {
  87       scm_t_port *pt = SCM_PTAB_ENTRY (new);
  88       scm_t_port *old_pt = SCM_PTAB_ENTRY (old);
  89       scm_t_ptob_descriptor *ptob = &scm_ptobs[SCM_PTOBNUM (new)];
  90
  91       /* must flush to old fdes.  */
  92       if (pt->rw_active == SCM_PORT_WRITE)
  93         ptob->flush (new);
  94       else if (pt->rw_active == SCM_PORT_READ)
  95         scm_end_input (new);
  96       ans = dup2 (oldfd, newfd);
  97       if (ans == -1)
  98         SCM_SYSERROR;
  99       pt->rw_random = old_pt->rw_random;
 100       /* continue using existing buffers, even if inappropriate.  */
 101     }
 102   return SCM_UNSPECIFIED;
 103 }
 104 #undef FUNC_NAME
 105
 106 SCM_DEFINE (scm_dup_to_fdes, "dup->fdes", 1, 1, 0,
 107             (SCM fd_or_port, SCM fd),
 108             "Return a new integer file descriptor referring to the open file\n"
 109             "designated by @var{fd_or_port}, which must be either an open\n"
 110             "file port or a file descriptor.")
 111 #define FUNC_NAME s_scm_dup_to_fdes
 112 {
 113   int oldfd, newfd, rv;
 114
 115   fd_or_port = SCM_COERCE_OUTPORT (fd_or_port);
 116
 117   if (SCM_INUMP (fd_or_port))
 118     oldfd = SCM_INUM (fd_or_port);
 119   else
 120     {
 121       SCM_VALIDATE_OPFPORT (1, fd_or_port);
 122       oldfd = SCM_FPORT_FDES (fd_or_port);
 123     }
 124
 125   if (SCM_UNBNDP (fd))
 126     {
 127       newfd = dup (oldfd);
 128       if (newfd == -1)
 129         SCM_SYSERROR;
 130       fd = SCM_I_MAKINUM (newfd);
 131     }
 132   else
 133     {
 134       SCM_VALIDATE_INUM_COPY (2, fd, newfd);
 135       if (oldfd != newfd)
 136         {
 137           scm_evict_ports (newfd);      /* see scsh manual.  */
 138           rv = dup2 (oldfd, newfd);
 139           if (rv == -1)
 140             SCM_SYSERROR;
 141         }
 142     }
 143   return fd;
 144 }
 145 #undef FUNC_NAME
 146
 147
 148 SCM_DEFINE (scm_dup2, "dup2", 2, 0, 0,
 149             (SCM oldfd, SCM newfd),
 150             "A simple wrapper for the @code{dup2} system call.\n"
 151             "Copies the file descriptor @var{oldfd} to descriptor\n"
 152             "number @var{newfd}, replacing the previous meaning\n"
 153             "of @var{newfd}.  Both @var{oldfd} and @var{newfd} must\n"
 154             "be integers.\n"
 155             "Unlike for dup->fdes or primitive-move->fdes, no attempt\n"
 156             "is made to move away ports which are using @var{newfd}.\n"
 157             "The return value is unspecified.")
 158 #define FUNC_NAME s_scm_dup2
 159 {
 160   int c_oldfd;
 161   int c_newfd;
 162   int rv;
 163
 164   SCM_VALIDATE_INUM_COPY (1, oldfd, c_oldfd);
 165   SCM_VALIDATE_INUM_COPY (2, newfd, c_newfd);
 166   rv = dup2 (c_oldfd, c_newfd);
 167   if (rv == -1)
 168     SCM_SYSERROR;
 169   return SCM_UNSPECIFIED;
 170 }
 171 #undef FUNC_NAME
 172
 173 SCM_DEFINE (scm_fileno, "fileno", 1, 0, 0,
 174             (SCM port),
 175             "Return the integer file descriptor underlying @var{port}.  Does\n"
 176             "not change its revealed count.")
 177 #define FUNC_NAME s_scm_fileno
 178 {
 179   port = SCM_COERCE_OUTPORT (port);
 180   SCM_VALIDATE_OPFPORT (1, port);
 181   return SCM_I_MAKINUM (SCM_FPORT_FDES (port));
 182 }
 183 #undef FUNC_NAME
 184
 185 /* GJB:FIXME:: why does this not throw
 186    an error if the arg is not a port?
 187    This proc as is would be better names isattyport?
 188    if it is not going to assume that the arg is a port
 189
 190    [cmm] I don't see any problem with the above.  why should a type
 191    predicate assume _anything_ about its argument?
 192 */
 193 SCM_DEFINE (scm_isatty_p, "isatty?", 1, 0, 0,
 194             (SCM port),
 195             "Return @code{#t} if @var{port} is using a serial non--file\n"
 196             "device, otherwise @code{#f}.")
 197 #define FUNC_NAME s_scm_isatty_p
 198 {
 199   int rv;
 200
 201   port = SCM_COERCE_OUTPORT (port);
 202
 203   if (!SCM_OPFPORTP (port))
 204     return SCM_BOOL_F;
 205
 206   rv = isatty (SCM_FPORT_FDES (port));
 207   return  scm_from_bool(rv);
 208 }
 209 #undef FUNC_NAME
 210
 211
 212
 213 SCM_DEFINE (scm_fdopen, "fdopen", 2, 0, 0,
 214             (SCM fdes, SCM modes),
 215             "Return a new port based on the file descriptor @var{fdes}.\n"
 216             "Modes are given by the string @var{modes}.  The revealed count\n"
 217             "of the port is initialized to zero.  The modes string is the\n"
 218             "same as that accepted by @ref{File Ports, open-file}.")
 219 #define FUNC_NAME s_scm_fdopen
 220 {
 221   SCM_VALIDATE_INUM (1, fdes);
 222   SCM_VALIDATE_STRING (2, modes);
 223
 224   return scm_fdes_to_port (SCM_INUM (fdes), SCM_STRING_CHARS (modes), SCM_BOOL_F);
 225 }
 226 #undef FUNC_NAME
 227
 228
 229
 230 /* Move a port's underlying file descriptor to a given value.
 231  * Returns  #f if fdes is already the given value.
 232  *          #t if fdes moved.
 233  * MOVE->FDES is implemented in Scheme and calls this primitive.
 234  */
 235 SCM_DEFINE (scm_primitive_move_to_fdes, "primitive-move->fdes", 2, 0, 0,
 236             (SCM port, SCM fd),
 237             "Moves the underlying file descriptor for @var{port} to the integer\n"
 238             "value @var{fdes} without changing the revealed count of @var{port}.\n"
 239             "Any other ports already using this descriptor will be automatically\n"
 240             "shifted to new descriptors and their revealed counts reset to zero.\n"
 241             "The return value is @code{#f} if the file descriptor already had the\n"
 242             "required value or @code{#t} if it was moved.")
 243 #define FUNC_NAME s_scm_primitive_move_to_fdes
 244 {
 245   scm_t_fport *stream;
 246   int old_fd;
 247   int new_fd;
 248   int rv;
 249
 250   port = SCM_COERCE_OUTPORT (port);
 251
 252   SCM_VALIDATE_OPFPORT (1, port);
 253   SCM_VALIDATE_INUM (2, fd);
 254   stream = SCM_FSTREAM (port);
 255   old_fd = stream->fdes;
 256   new_fd = SCM_INUM (fd);
 257   if  (old_fd == new_fd)
 258     {
 259       return SCM_BOOL_F;
 260     }
 261   scm_evict_ports (new_fd);
 262   rv = dup2 (old_fd, new_fd);
 263   if (rv == -1)
 264     SCM_SYSERROR;
 265   stream->fdes = new_fd;
 266   SCM_SYSCALL (close (old_fd));
 267   return SCM_BOOL_T;
 268 }
 269 #undef FUNC_NAME
 270
 271 /* Return a list of ports using a given file descriptor.  */
 272 SCM_DEFINE (scm_fdes_to_ports, "fdes->ports", 1, 0, 0,
 273            (SCM fd),
 274             "Return a list of existing ports which have @var{fdes} as an\n"
 275             "underlying file descriptor, without changing their revealed\n"
 276             "counts.")
 277 #define FUNC_NAME s_scm_fdes_to_ports
 278 {
 279   SCM result = SCM_EOL;
 280   int int_fd;
 281   long i;
 282
 283   SCM_VALIDATE_INUM_COPY (1, fd, int_fd);
 284
 285   scm_mutex_lock (&scm_i_port_table_mutex);
 286   for (i = 0; i < scm_i_port_table_size; i++)
 287     {
 288       if (SCM_OPFPORTP (scm_i_port_table[i]->port)
 289           && ((scm_t_fport *) scm_i_port_table[i]->stream)->fdes == int_fd)
 290         result = scm_cons (scm_i_port_table[i]->port, result);
 291     }
 292   scm_mutex_unlock (&scm_i_port_table_mutex);
 293   return result;
 294 }
 295 #undef FUNC_NAME
 296
 297
 298 void
 299 scm_init_ioext ()
 300 {
 301   scm_add_feature ("i/o-extensions");
 302
 303 #include "libguile/ioext.x"
 304 }
 305
 306
 307 /*
 308   Local Variables:
 309   c-file-style: "gnu"
 310   End:
 311 */