lib/ss/get_readline.c

   1 /*
   2  * Copyright 2003 by MIT Student Information Processing Board
   3  *
   4  * Permission to use, copy, modify, and distribute this software and
   5  * its documentation for any purpose is hereby granted, provided that
   6  * the names of M.I.T. and the M.I.T. S.I.P.B. not be used in
   7  * advertising or publicity pertaining to distribution of the software
   8  * without specific, written prior permission.  M.I.T. and the
   9  * M.I.T. S.I.P.B. make no representations about the suitability of
  10  * this software for any purpose.  It is provided "as is" without
  11  * express or implied warranty.
  12  */
  13
  14 #ifdef HAS_STDLIB_H
  15 #include <stdlib.h>
  16 #endif
  17 #include "ss_internal.h"
  18 #define size    sizeof(ss_data *)
  19 #ifdef HAVE_DLOPEN
  20 #include <dlfcn.h>
  21 #endif
  22
  23 static void ss_release_readline(ss_data *info)
  24 {
  25 #ifdef HAVE_DLOPEN
  26         if (!info->readline_handle)
  27                 return;
  28
  29         info->readline = 0;
  30         info->add_history = 0;
  31         info->redisplay = 0;
  32         info->rl_completion_matches = 0;
  33         dlclose(info->readline_handle);
  34         info->readline_handle = 0;
  35 #endif
  36 }
  37
  38 /* Libraries we will try to use for readline/editline functionality */
  39 #define DEFAULT_LIBPATH "libreadline.so.4:libreadline.so:libedit.so.2:libedit.so:libeditline.so.0:libeditline.so"
  40
  41 void ss_get_readline(int sci_idx)
  42 {
  43 #ifdef HAVE_DLOPEN
  44         void    *handle = NULL;
  45         ss_data *info = ss_info(sci_idx);
  46         const char **t, *libpath = 0;
  47         char    *tmp, *cp, *next;
  48         char **(**completion_func)(const char *, int, int);
  49
  50         if (info->readline_handle)
  51                 return;
  52
  53         libpath = getenv("SS_READLINE_PATH");
  54         if (!libpath)
  55                 libpath = DEFAULT_LIBPATH;
  56         if (*libpath == 0 || !strcmp(libpath, "none"))
  57                 return;
  58
  59         tmp = malloc(strlen(libpath)+1);
  60         if (!tmp)
  61                 return;
  62         strcpy(tmp, libpath);
  63         for (cp = tmp; cp; cp = next) {
  64                 next = strchr(cp, ':');
  65                 if (next)
  66                         *next++ = 0;
  67                 if (*cp == 0)
  68                         continue;
  69                 if ((handle = dlopen(cp, RTLD_NOW))) {
  70                         /* printf("Using %s for readline library\n", cp); */
  71                         break;
  72                 }
  73         }
  74         free(tmp);
  75         if (!handle)
  76                 return;
  77
  78         info->readline_handle = handle;
  79         info->readline = (char *(*)(const char *))
  80                 dlsym(handle, "readline");
  81         info->add_history = (void (*)(const char *))
  82                 dlsym(handle, "add_history");
  83         info->redisplay = (void (*)(void))
  84                 dlsym(handle, "rl_forced_update_display");
  85         info->rl_completion_matches = (char **(*)(const char *,
  86                                     char *(*)(const char *, int)))
  87                 dlsym(handle, "rl_completion_matches");
  88         if ((t = dlsym(handle, "rl_readline_name")) != NULL)
  89                 *t = info->subsystem_name;
  90         if ((completion_func =
  91              dlsym(handle, "rl_attempted_completion_function")) != NULL)
  92                 *completion_func = ss_rl_completion;
  93         info->readline_shutdown = ss_release_readline;
  94 #endif
  95 }
  96
  97