/*

 * This file is part of zsh, the Z shell.

 *

 * Copyright (c) 1992-1997 Paul Falstad

 * All rights reserved.

 *

 * Permission is hereby granted, without written agreement and without

 * license or royalty fees, to use, copy, modify, and distribute this

 * software and to distribute modified versions of this software for any

 * purpose, provided that the above copyright notice and the following

 * two paragraphs appear in all copies of this software.

 *

 * In no event shall Paul Falstad or the Zsh Development Group be liable

 * to any party for direct, indirect, special, incidental, or consequential

 * damages arising out of the use of this software and its documentation,

 * even if Paul Falstad and the Zsh Development Group have been advised of

 * the possibility of such damage.

 *

 * Paul Falstad and the Zsh Development Group specifically disclaim any

 * warranties, including, but not limited to, the implied warranties of

 * merchantability and fitness for a particular purpose.  The software

 * provided hereunder is on an "as is" basis, and Paul Falstad and the

 * Zsh Development Group have no obligation to provide maintenance,

 * support, updates, enhancements, or modifications.

 *

 */

/*

 * This file deals with input buffering, supplying characters to the

 * history expansion code a character at a time.  Input is stored on a

 * stack, which allows insertion of strings into the input, possibly with

 * flags marking the end of alias expansion, with minimal copying of

 * strings.  The same stack is used to record the fact that the input

 * is a history or alias expansion and to store the alias while it is in use.

 * 

 * Input is taken either from zle, if appropriate, or read directly from

 * the input file, or may be supplied by some other part of the shell (such

 * as `eval' or $(...) substitution).  In the last case, it should be

 * supplied by pushing a new level onto the stack, via inpush(input_string,

 * flag, alias); if the current input really needs to be altered, use

 * inputsetline(input_string, flag).  `Flag' can include or's of INP_FREE

 * (if the input string is to be freed when used), INP_CONT (if the input

 * is to continue onto what's already in the input queue), INP_ALIAS

 * (push supplied alias onto stack) or INP_HIST (ditto, but used to

 * mark history expansion).  `alias' is ignored unless INP_ALIAS or

 * INP_HIST is supplied.  INP_ALIAS is always set if INP_HIST is.

 * 

 * Note that the input string is itself used as the input buffer: it is not

 * copied, nor is it every written back to, so using a constant string

 * should work.  Consequently, when passing areas of memory from the heap

 * it is necessary that that heap last as long as the operation of reading

 * the string.  After the string is read, the stack should be popped with

 * inpop(), which effectively flushes any unread input as well as restoring

 * the previous input state.

 *

 * The internal flag INP_ALCONT shows that the stack element was pushed

 * by an alias expansion; it should not be needed elsewhere.

 *

 * The global variable inalmore is set to indicate aliases should

 * continue to be expanded because the last alias expansion ended

 * in a space.  It is only reset after a complete word was read

 * without expanding a new alias, in exalias().

 *

 * PWS 1996/12/10

 */

#ifdef HAVE_STDIO_H

#include <stdio.h>

#endif

#include "zsh.mdh"

#include "input.pro"

/* the shell input fd */

/**/

int SHIN;

/* buffered shell input for non-interactive shells */

/**/

FILE *bshin;

/* != 0 means we are reading input from a string */

/**/

int strin;

/* total # of characters waiting to be read. */

/**/

mod_export int inbufct;

/* the flags controlling the input routines in input.c: see INP_* in zsh.h */

/**/

int inbufflags;

static char *inbuf;		/* Current input buffer */

static char *inbufptr;		/* Pointer into input buffer */

static char *inbufpush;		/* Character at which to re-push alias */

static int inbufleft;		/* Characters left in current input

				   stack element */

 /* Input must be stacked since the input queue is used by

  * various different parts of the shell.

  */

struct instacks {

    char *buf, *bufptr;

    Alias alias;

    int bufleft, bufct, flags;

};

static struct instacks *instack, *instacktop;

/*

 * Input stack size.  We need to push the stack for aliases, history

 * expansion, and reading from internal strings: only if these operations

 * are nested do we need more than one extra level.  Thus we shouldn't need

 * too much space as a rule.  Initially, INSTACK_INITIAL is allocated; if

 * more is required, an extra INSTACK_EXPAND is added each time.

 */

#define INSTACK_INITIAL	4

#define INSTACK_EXPAND	4

static int instacksz = INSTACK_INITIAL;

/* Read a line from bshin.  Convert tokens and   *

 * null characters to Meta c^32 character pairs. */

/**/

mod_export char *

shingetline(void)

{

    char *line = NULL;

    int ll = 0;

    int c;

    char buf[BUFSIZ];

    char *p;

    p = buf;

    for (;;) {

	do {

	    errno = 0;

	    c = fgetc(bshin);

	} while (c < 0 && errno == EINTR);

	if (c < 0 || c == '\n') {

	    if (c == '\n')

		*p++ = '\n';

	    if (p > buf) {

		*p++ = '\0';

		line = zrealloc(line, ll + (p - buf));

		memcpy(line + ll, buf, p - buf);

	    }

	    return line;

	}

	if (imeta(c)) {

	    *p++ = Meta;

	    *p++ = c ^ 32;

	} else

	    *p++ = c;

	if (p >= buf + BUFSIZ - 1) {

	    line = zrealloc(line, ll + (p - buf) + 1);

	    memcpy(line + ll, buf, p - buf);

	    ll += p - buf;

	    line[ll] = '\0';

	    p = buf;

	}

    }

}

/* Get the next character from the input.

 * Will call inputline() to get a new line where necessary.

 */

/**/

int

ingetc(void)

{

    int lastc;

    if (lexstop)

	return ' ';

    for (;;) {

	if (inbufleft) {

	    inbufleft--;

	    inbufct--;

	    if (itok(lastc = STOUC(*inbufptr++)))

		continue;

	    if (((inbufflags & INP_LINENO) || !strin) && lastc == '\n')

		lineno++;

	    return lastc;

	}

	/* If the next element down the input stack is a continuation of

	 * this, use it.

	 */ 

	if (inbufflags & INP_CONT) {

	    inpoptop();

	    continue;

	}

	/*

	 * Otherwise, see if we have reached the end of input

	 * (due to an error, or to reading from a single string).

	 */

	if (strin || errflag) {

	    lexstop = 1;

	    return ' ';

	}

	/* As a last resort, get some more input */

	if (inputline())

	    return ' ';

    }

}

/* Read a line from the current command stream and store it as input */

/**/

static int

inputline(void)

{

    char *ingetcline, **ingetcpmptl = NULL, **ingetcpmptr = NULL;

    int context = ZLCON_LINE_START;

    /* If reading code interactively, work out the prompts. */

    if (interact && isset(SHINSTDIN)) {

	if (!isfirstln) {

	    ingetcpmptl = &prompt2;

	    if (rprompt2)

		ingetcpmptr = &rprompt2;

	    context = ZLCON_LINE_CONT;

	}

	else {

	    ingetcpmptl = &prompt;

	    if (rprompt)

		ingetcpmptr = &rprompt;

	}

    }

    if (!(interact && isset(SHINSTDIN) && SHTTY != -1 && isset(USEZLE))) {

	/*

	 * If not using zle, read the line straight from the input file.

	 * Possibly we don't get the whole line at once:  in that case,

	 * we get another chunk with the next call to inputline().

	 */

	if (interact && isset(SHINSTDIN)) {

	    /*

	     * We may still be interactive (e.g. running under emacs),

	     * so output a prompt if necessary.  We don't know enough

	     * about the input device to be able to handle an rprompt,

	     * though.

	     */

	    char *pptbuf;

	    int pptlen;

	    pptbuf = unmetafy(promptexpand(ingetcpmptl ? *ingetcpmptl : NULL,

					   0, NULL, NULL), &pptlen);

	    write(1, (WRITE_ARG_2_T)pptbuf, pptlen);

	    free(pptbuf);

	}

	ingetcline = shingetline();

    } else {

	/*

	 * Since we may have to read multiple lines before getting

	 * a complete piece of input, we tell zle not to restore the

	 * original tty settings after reading each chunk.  Instead,

	 * this is done when the history mechanism for the current input

	 * terminates, which is not until we have the whole input.

	 * This is supposed to minimise problems on systems that clobber

	 * typeahead when the terminal settings are altered.

	 *                     pws 1998/03/12

	 */

	int flags = ZLRF_HISTORY|ZLRF_NOSETTY;

	if (isset(IGNOREEOF))

	    flags |= ZLRF_IGNOREEOF;

	ingetcline = (char *)zleread(ingetcpmptl, ingetcpmptr, flags,

				     context);

	histdone |= HISTFLAG_SETTY;

    }

    if (!ingetcline) {

	return lexstop = 1;

    }

    if (errflag) {

	free(ingetcline);

	return lexstop = errflag = 1;

    }

    if (isset(VERBOSE)) {

	/* Output the whole line read so far. */

	zputs(ingetcline, stderr);

	fflush(stderr);

    }

    if (*ingetcline && ingetcline[strlen(ingetcline) - 1] == '\n' &&

	interact && isset(SUNKEYBOARDHACK) && isset(SHINSTDIN) &&

	SHTTY != -1 && *ingetcline && ingetcline[1] &&

	ingetcline[strlen(ingetcline) - 2] == '`') {

	/* Junk an unmatched "`" at the end of the line. */

	int ct;

	char *ptr;

	for (ct = 0, ptr = ingetcline; *ptr; ptr++)

	    if (*ptr == '`')

		ct++;

	if (ct & 1) {

	    ptr[-2] = '\n';

	    ptr[-1] = '\0';

	}

    }

    isfirstch = 1;

    /* Put this into the input channel. */

    inputsetline(ingetcline, INP_FREE);

    return 0;

}

/*

 * Put a string in the input queue:

 * inbuf is only freeable if the flags include INP_FREE.

 */

/**/

static void

inputsetline(char *str, int flags)

{

    if ((inbufflags & INP_FREE) && inbuf) {

	free(inbuf);

    }

    inbuf = inbufptr = str;

    inbufleft = strlen(inbuf);

    /*

     * inbufct must reflect the total number of characters left,

     * as it used by other parts of the shell, so we need to take account

     * of whether the input stack continues, and whether there

     * is an extra space to add on at the end.

     */

    if (flags & INP_CONT)

	inbufct += inbufleft;

    else

	inbufct = inbufleft;

    inbufflags = flags;

}

/*

 * Backup one character of the input.

 * The last character can always be backed up, provided we didn't just

 * expand an alias or a history reference.

 * In fact, the character is ignored and the previous character is used.

 * (If that's wrong, the bug is in the calling code.  Use the #ifdef DEBUG

 * code to check.) 

 */

/**/

void

inungetc(int c)

{

    if (!lexstop) {

	if (inbufptr != inbuf) {

#ifdef DEBUG

	    /* Just for debugging: enable only if foul play suspected. */

	    if (inbufptr[-1] != (char) c)

		fprintf(stderr, "Warning: backing up wrong character.\n");

#endif

	    /* Just decrement the pointer:  if it's not the same

	     * character being pushed back, we're in trouble anyway.

	     */

	    inbufptr--;

	    inbufct++;

	    inbufleft++;

	    if (((inbufflags & INP_LINENO) || !strin) && c == '\n')

		lineno--;

	}

#ifdef DEBUG

        else if (!(inbufflags & INP_CONT)) {

	    /* Just for debugging */

	    fprintf(stderr, "Attempt to inungetc() at start of input.\n");

	}

#endif

	else {

	    /*

	     * The character is being backed up from a previous input stack

	     * layer.  However, there was an expansion in the middle, so we

	     * can't back up where we want to.  Instead, we just push it

	     * onto the input stack as an extra character.

	     */

	    char *cback = (char *)zshcalloc(2);

	    cback[0] = (char) c;

	    inpush(cback, INP_FREE|INP_CONT, NULL);

	}

	/* If we are back at the start of a segment,

	 * we may need to restore an alias popped from the stack.

	 * Note this may be a dummy (history expansion) entry.

	 */

	if (inbufptr == inbufpush && inbufflags & INP_ALCONT) {

	    /*

	     * Go back up the stack over all entries which were alias

	     * expansions and were pushed with nothing remaining to read.

	     */

	    do {

		if (instacktop->alias)

		    instacktop->alias->inuse = 1;

		instacktop++;

	    } while ((instacktop->flags & INP_ALCONT) && !instacktop->bufleft);

	    inbufflags = INP_CONT|INP_ALIAS;

	    inbufleft = 0;

	    inbuf = inbufptr = "";

	}

    }

}

/* stuff a whole file into the input queue and print it */

/**/

int

stuff(char *fn)

{

    FILE *in;

    char *buf;

    off_t len;

    if (!(in = fopen(unmeta(fn), "r"))) {    

	zerr("can't open %s", fn, 0);

	return 1;

    }

    fseek(in, 0, 2);

    len = ftell(in);

    fseek(in, 0, 0);

    buf = (char *)zalloc(len + 1);

    if (!(fread(buf, len, 1, in))) {

	zerr("read error on %s", fn, 0);

	fclose(in);

	zfree(buf, len + 1);

	return 1;

    }

    fclose(in);

    buf[len] = '\0';

    fwrite(buf, len, 1, stderr);

    fflush(stderr);

#ifndef __SYMBIAN32__    

    inputsetline(metafy(buf, len, META_REALLOC), INP_FREE);

#endif    

    return 0;

}

/* flush input queue */

/**/

void

inerrflush(void)

{

    while (!lexstop && inbufct)

	ingetc();

}

/* Set some new input onto a new element of the input stack */

/**/

mod_export void

inpush(char *str, int flags, Alias inalias)

{

    if (!instack) {

	/* Initial stack allocation */

	instack = (struct instacks *)zalloc(instacksz*sizeof(struct instacks));

	instacktop = instack;

    }

    instacktop->buf = inbuf;

    instacktop->bufptr = inbufptr;

    instacktop->bufleft = inbufleft;

    instacktop->bufct = inbufct;

    inbufflags &= ~INP_ALCONT;

    if (flags & (INP_ALIAS|INP_HIST)) {

	/*

	 * Text is expansion for history or alias, so continue

	 * back to old level when done.  Also mark stack top

	 * as alias continuation so as to back up if necessary,

	 * and mark alias as in use.

	 */

	flags |= INP_CONT|INP_ALIAS;

	instacktop->flags = inbufflags | INP_ALCONT;

	if ((instacktop->alias = inalias))

	    inalias->inuse = 1;

    } else {

	/* If we are continuing an alias expansion, record the alias

	 * expansion in new set of flags (do we need this?)

	 */

	if (((instacktop->flags = inbufflags) & INP_ALIAS) &&

	    (flags & INP_CONT))

	    flags |= INP_ALIAS;

    }

    instacktop++;

    if (instacktop == instack + instacksz) {

	/* Expand the stack */

	instack = (struct instacks *)

	    realloc(instack,

		    (instacksz + INSTACK_EXPAND)*sizeof(struct instacks));

	instacktop = instack + instacksz;

	instacksz += INSTACK_EXPAND;

    }

    /*

     * We maintain the entry above the highest one with real

     * text as a flag to inungetc() that it can stop re-pushing the stack.

     */

    instacktop->flags = 0;

    inbufpush = inbuf = NULL;

    inputsetline(str, flags);

}