lib/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 1, 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    675 Mass Ave, Cambridge, MA 02139, 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 #include <stdio.h>
  34
  35 /* System-specific feature definitions and include files. */
  36 #include "rldefs.h"
  37 #include "readline.h"
  38
  39 extern void readline_internal_setup ();
  40 extern char *readline_internal_teardown ();
  41 extern int readline_internal_char ();
  42 extern void _rl_init_line_state ();
  43
  44 extern int _rl_meta_flag;
  45 extern char *rl_prompt;
  46 extern int rl_visible_prompt_length;
  47
  48 /* **************************************************************** */
  49 /*                                                                  */
  50 /*                      Callback Readline Functions                 */
  51 /*                                                                  */
  52 /* **************************************************************** */
  53
  54 /* Allow using readline in situations where a program may have multiple
  55    things to handle at once, and dispatches them via select().  Call
  56    rl_callback_handler_install() with the prompt and a function to call
  57    whenever a complete line of input is ready.  The user must then
  58    call rl_callback_read_char() every time some input is available, and
  59    rl_callback_read_char() will call the user's function with the complete
  60    text read in at each end of line.  The terminal is kept prepped and
  61    signals handled all the time, except during calls to the user's function. */
  62
  63 VFunction *rl_linefunc;         /* user callback function */
  64 static int in_handler;          /* terminal_prepped and signals set? */
  65
  66 /* Make sure the terminal is set up, initialize readline, and prompt. */
  67 static void
  68 _rl_callback_newline ()
  69 {
  70   rl_initialize ();
  71
  72   if (in_handler == 0)
  73     {
  74       in_handler = 1;
  75
  76       (*rl_prep_term_function) (_rl_meta_flag);
  77
  78 #if defined (HANDLE_SIGNALS)
  79       rl_set_signals ();
  80 #endif
  81     }
  82
  83   readline_internal_setup ();
  84 }
  85
  86 /* Install a readline handler, set up the terminal, and issue the prompt. */
  87 void
  88 rl_callback_handler_install (prompt, linefunc)
  89      char *prompt;
  90      VFunction *linefunc;
  91 {
  92   rl_prompt = prompt;
  93   rl_visible_prompt_length = rl_prompt ? rl_expand_prompt (rl_prompt) : 0;
  94   rl_linefunc = linefunc;
  95   _rl_callback_newline ();
  96 }
  97
  98 /* Read one character, and dispatch to the handler if it ends the line. */
  99 void
 100 rl_callback_read_char ()
 101 {
 102   char *line;
 103   int eof;
 104
 105   if (rl_linefunc == NULL)
 106     {
 107       fprintf (stderr, "readline: readline_callback_read_char() called with no handler!\r\n");
 108       abort ();
 109     }
 110
 111   eof = readline_internal_char ();
 112
 113   if (rl_done)
 114     {
 115       line = readline_internal_teardown (eof);
 116
 117       (*rl_deprep_term_function) ();
 118 #if defined (HANDLE_SIGNALS)
 119       rl_clear_signals ();
 120 #endif
 121       in_handler = 0;
 122       (*rl_linefunc) (line);
 123
 124     /* If the user did not clear out the line, do it for him. */
 125     if (rl_line_buffer[0])
 126       _rl_init_line_state ();
 127
 128     /* Redisplay the prompt if readline_handler_{install,remove} not called. */
 129       if (in_handler == 0 && rl_linefunc)
 130         _rl_callback_newline ();
 131     }
 132 }
 133
 134 /* Remove the handler, and make sure the terminal is in its normal state. */
 135 void
 136 rl_callback_handler_remove ()
 137 {
 138   rl_linefunc = NULL;
 139   if (in_handler)
 140     {
 141       in_handler = 0;
 142       (*rl_deprep_term_function) ();
 143 #if defined (HANDLE_SIGNALS)
 144       rl_clear_signals ();
 145 #endif
 146     }
 147 }
 148
 149 #endif