Parser/myreadline.c

/***********************************************************
Copyright 1991-1995 by Stichting Mathematisch Centrum, Amsterdam,
The Netherlands.

                        All Rights Reserved

Permission to use, copy, modify, and distribute this software and its 
documentation for any purpose and without fee is hereby granted, 
provided that the above copyright notice appear in all copies and that
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Centrum or CWI not be used in advertising or publicity pertaining to
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STICHTING MATHEMATISCH CENTRUM DISCLAIMS ALL WARRANTIES WITH REGARD TO
THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
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WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

******************************************************************/

/* Readline interface for tokenizer.c.
   By default, we have a super simple my_readline function.
   Optionally, we can use the GNU readline library (to be found in the
   bash distribution).
   my_readline() has a different return value from GNU readline():
   - NULL if an interrupt occurred or if an error occurred
   - a malloc'ed empty string if EOF was read
   - a malloc'ed string ending in \n normally
*/

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <stdio.h>
#include <string.h>
#include <errno.h>

#include "myproto.h"
#include "mymalloc.h"
#include "intrcheck.h"

#ifdef WITH_READLINE

extern char *readline();

#include <setjmp.h>
#include <signal.h>

static jmp_buf jbuf;

/* ARGSUSED */
static RETSIGTYPE
onintr(sig)
	int sig;
{
	longjmp(jbuf, 1);
}

#else /* !WITH_READLINE */

/* This function restarts a fgets() after an EINTR error occurred
   except if intrcheck() returns true. */

static int
my_fgets(buf, len, fp)
	char *buf;
	int len;
	FILE *fp;
{
	char *p;
	for (;;) {
		errno = 0;
		p = fgets(buf, len, fp);
		if (p != NULL)
			return 0; /* No error */
		if (feof(fp)) {
			return -1; /* EOF */
		}
#ifdef EINTR
		if (errno == EINTR) {
			if (intrcheck()) {
				return 1; /* Interrupt */
			}
			continue;
		}
#endif
		if (intrcheck()) {
			return 1; /* Interrupt */
		}
		return -2; /* Error */
	}
	/* NOTREACHED */
}

#endif /* WITH_READLINE */


char *
my_readline(prompt)
	char *prompt;
{
	int n;
	char *p;
#ifdef WITH_READLINE
	RETSIGTYPE (*old_inthandler)();
	static int been_here;
	if (!been_here) {
		/* Force rebind of TAB to insert-tab */
		extern int rl_insert();
		rl_bind_key('\t', rl_insert);
		been_here++;
	}
	old_inthandler = signal(SIGINT, onintr);
	if (setjmp(jbuf)) {
#ifdef HAVE_SIGRELSE
		/* This seems necessary on SunOS 4.1 (Rasmus Hahn) */
		sigrelse(SIGINT);
#endif
		signal(SIGINT, old_inthandler);
		return NULL;
	}
	p = readline(prompt);
	signal(SIGINT, old_inthandler);
	if (p == NULL) {
		p = malloc(1);
		if (p != NULL)
			*p = '\0';
		return p;
	}
	n = strlen(p);
	if (n > 0)
		add_history(p);
	if ((p = realloc(p, n+2)) != NULL) {
		p[n] = '\n';
		p[n+1] = '\0';
	}
	return p;
#else /* !WITH_READLINE */
	n = 100;
	if ((p = malloc(n)) == NULL)
		return NULL;
	fflush(stdout);
	if (prompt)
		fprintf(stderr, "%s", prompt);
	fflush(stderr);
	switch (my_fgets(p, n, stdin)) {
	case 0: /* Normal case */
		break;
	case 1: /* Interrupt */
		free(p);
		return NULL;
	case -1: /* EOF */
	case -2: /* Error */
	default: /* Shouldn't happen */
		*p = '\0';
		break;
	}
#ifdef MPW
	/* Hack for MPW C where the prompt comes right back in the input */
	/* XXX (Actually this would be rather nice on most systems...) */
	n = strlen(prompt);
	if (strncmp(p, prompt, n) == 0)
		memmove(p, p + n, strlen(p) - n + 1);
#endif
	n = strlen(p);
	while (n > 0 && p[n-1] != '\n') {
		int incr = n+2;
		p = realloc(p, n + incr);
		if (p == NULL)
			return NULL;
		if (my_fgets(p+n, incr, stdin) != 0)
			break;
		n += strlen(p+n);
	}
	return realloc(p, n+1);
#endif /* !WITH_READLINE */
}