readline/callback.c

   1 /* callback.c -- functions to use readline as an X `callback' mechanism. */
   2
   3 /* Copyright (C) 1987, 1989, 1992 Free Software Foundation, Inc.
   4
   5    This file is part of the GNU Readline Library, a library for
   6    reading lines of text with interactive input and history editing.
   7
   8    The GNU Readline Library is free software; you can redistribute it
   9    and/or modify it under the terms of the GNU General Public License
  10    as published by the Free Software Foundation; either version 2, or
  11    (at your option) any later version.
  12
  13    The GNU Readline Library is distributed in the hope that it will be
  14    useful, but WITHOUT ANY WARRANTY; without even the implied warranty
  15    of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    The GNU General Public License is often shipped with GNU software, and
  19    is generally kept in a file called COPYING or LICENSE.  If you do not
  20    have a copy of the license, write to the Free Software Foundation,
  21    59 Temple Place, Suite 330, Boston, MA 02111 USA. */
  22 #define READLINE_LIBRARY
  23
  24 #if defined (HAVE_CONFIG_H)
  25 #  include <config.h>
  26 #endif
  27
  28 #include "rlconf.h"
  29
  30 #if defined (READLINE_CALLBACKS)
  31
  32 #include <sys/types.h>
  33
  34 #ifdef HAVE_STDLIB_H
  35 #  include <stdlib.h>
  36 #else
  37 #  include "ansi_stdlib.h"
  38 #endif
  39
  40 #include <stdio.h>
  41
  42 /* System-specific feature definitions and include files. */
  43 #include "rldefs.h"
  44 #include "readline.h"
  45 #include "rlprivate.h"
  46
  47 /* **************************************************************** */
  48 /*                                                                  */
  49 /*                      Callback Readline Functions                 */
  50 /*                                                                  */
  51 /* **************************************************************** */
  52
  53 /* Allow using readline in situations where a program may have multiple
  54    things to handle at once, and dispatches them via select().  Call
  55    rl_callback_handler_install() with the prompt and a function to call
  56    whenever a complete line of input is ready.  The user must then
  57    call rl_callback_read_char() every time some input is available, and
  58    rl_callback_read_char() will call the user's function with the complete
  59    text read in at each end of line.  The terminal is kept prepped and
  60    signals handled all the time, except during calls to the user's function. */
  61
  62 rl_vcpfunc_t *rl_linefunc;              /* user callback function */
  63 static int in_handler;          /* terminal_prepped and signals set? */
  64
  65 /* Make sure the terminal is set up, initialize readline, and prompt. */
  66 static void
  67 _rl_callback_newline ()
  68 {
  69   rl_initialize ();
  70
  71   if (in_handler == 0)
  72     {
  73       in_handler = 1;
  74
  75       (*rl_prep_term_function) (_rl_meta_flag);
  76
  77 #if defined (HANDLE_SIGNALS)
  78       rl_set_signals ();
  79 #endif
  80     }
  81
  82   readline_internal_setup ();
  83 }
  84
  85 /* Install a readline handler, set up the terminal, and issue the prompt. */
  86 void
  87 rl_callback_handler_install (prompt, linefunc)
  88      const char *prompt;
  89      rl_vcpfunc_t *linefunc;
  90 {
  91   rl_set_prompt (prompt);
  92   rl_linefunc = linefunc;
  93   _rl_callback_newline ();
  94 }
  95
  96 /* Read one character, and dispatch to the handler if it ends the line. */
  97 void
  98 rl_callback_read_char ()
  99 {
 100   char *line;
 101   int eof;
 102
 103   if (rl_linefunc == NULL)
 104     {
 105       fprintf (stderr, "readline: readline_callback_read_char() called with no handler!\r\n");
 106       abort ();
 107     }
 108
 109   eof = readline_internal_char ();
 110
 111   /* We loop in case some function has pushed input back with rl_execute_next. */
 112   for (;;)
 113     {
 114       if (rl_done)
 115         {
 116           line = readline_internal_teardown (eof);
 117
 118           (*rl_deprep_term_function) ();
 119 #if defined (HANDLE_SIGNALS)
 120           rl_clear_signals ();
 121 #endif
 122           in_handler = 0;
 123           (*rl_linefunc) (line);
 124
 125           /* If the user did not clear out the line, do it for him. */
 126           if (rl_line_buffer[0])
 127             _rl_init_line_state ();
 128
 129           /* Redisplay the prompt if readline_handler_{install,remove}
 130              not called. */
 131           if (in_handler == 0 && rl_linefunc)
 132             _rl_callback_newline ();
 133         }
 134       if (rl_pending_input)
 135         eof = readline_internal_char ();
 136       else
 137         break;
 138     }
 139 }
 140
 141 /* Remove the handler, and make sure the terminal is in its normal state. */
 142 void
 143 rl_callback_handler_remove ()
 144 {
 145   rl_linefunc = NULL;
 146   if (in_handler)
 147     {
 148       in_handler = 0;
 149       (*rl_deprep_term_function) ();
 150 #if defined (HANDLE_SIGNALS)
 151       rl_clear_signals ();
 152 #endif
 153     }
 154 }
 155
 156 #endif