term.c

早期freebsd实现

 * if it is the result of a mapping or an abbreviation, as well as a count
 * of the number of times it has been mapped.
 */
int
term_push(sp, s, nchars, cmap, flags)
	SCR *sp;
	CHAR_T *s;			/* Characters. */
	size_t nchars;			/* Number of chars. */
	u_int cmap;			/* Map count. */
	u_int flags;			/* CH_* flags. */
{
	IBUF *tty;

	/* If we have room, stuff the keys into the buffer. */
	tty = sp->gp->tty;
	if (nchars <= tty->next ||
	    (tty->ch != NULL && tty->cnt == 0 && nchars <= tty->nelem)) {
		if (tty->cnt != 0)
			tty->next -= nchars;
		tty->cnt += nchars;
		MEMMOVE(tty->ch + tty->next, s, nchars);
		MEMSET(tty->chf + tty->next, flags, nchars);
		MEMSET(tty->cmap + tty->next, cmap, nchars);
		return (0);
	}

	/* Get enough space plus a little extra. */
	if (tty->cnt + nchars >= tty->nelem &&
	    __term_read_grow(sp, tty, MAX(nchars, 64)))
		return (1);

	/*
	 * If there are currently characters in the queue, shift them up,
	 * leaving some extra room.
	 */
#define	TERM_PUSH_SHIFT	30
	if (tty->cnt) {
		MEMMOVE(tty->ch + TERM_PUSH_SHIFT + nchars,
		    tty->ch + tty->next, tty->cnt);
		MEMMOVE(tty->chf + TERM_PUSH_SHIFT + nchars,
		    tty->chf + tty->next, tty->cnt);
		MEMMOVE(tty->cmap + TERM_PUSH_SHIFT + nchars,
		    tty->cmap + tty->next, tty->cnt);
	}

	/* Put the new characters into the queue. */
	tty->next = TERM_PUSH_SHIFT;
	tty->cnt += nchars;
	MEMMOVE(tty->ch + TERM_PUSH_SHIFT, s, nchars);
	MEMSET(tty->chf + TERM_PUSH_SHIFT, flags, nchars);
	MEMSET(tty->cmap + TERM_PUSH_SHIFT, cmap, nchars);
	return (0);
}

/*
 * Remove characters from the queue, simultaneously clearing the flag
 * and map counts.
 */
#define	QREM_HEAD(q, len) {						\
	size_t __off = (q)->next;					\
	if (len == 1) {							\
		tty->chf[__off] = 0;					\
		tty->cmap[__off] = 0;					\
	} else {							\
		MEMSET(tty->chf + __off, 0, len);			\
		MEMSET(tty->cmap + __off, 0, len);			\
	}								\
	if (((q)->cnt -= len) == 0)					\
		(q)->next = 0;						\
	else								\
		(q)->next += len;					\
}
#define	QREM_TAIL(q, len) {						\
	size_t __off = (q)->next + (q)->cnt - 1;			\
	if (len == 1) {							\
		tty->chf[__off] = 0;					\
		tty->cmap[__off] = 0;					\
	} else {							\
		MEMSET(tty->chf + __off, 0, len);			\
		MEMSET(tty->cmap + __off, 0, len);			\
	}								\
	if (((q)->cnt -= len) == 0)					\
		(q)->next = 0;						\
}

/*
 * term_key --
 *	Get the next key.
 *
 * !!!
 * The flag TXT_MAPNODIGIT probably needs some explanation.  First, the idea
 * of mapping keys is that one or more keystrokes act like a function key.
 * What's going on is that vi is reading a number, and the character following
 * the number may or may not be mapped (TXT_MAPCOMMAND).  For example, if the
 * user is entering the z command, a valid command is "z40+", and we don't want
 * to map the '+', i.e. if '+' is mapped to "xxx", we don't want to change it
 * into "z40xxx".  However, if the user enters "35x", we want to put all of the
 * characters through the mapping code.
 *
 * Historical practice is a bit muddled here.  (Surprise!)  It always permitted
 * mapping digits as long as they weren't the first character of the map, e.g.
 * ":map ^A1 xxx" was okay.  It also permitted the mapping of the digits 1-9
 * (the digit 0 was a special case as it doesn't indicate the start of a count)
 * as the first character of the map, but then ignored those mappings.  While
 * it's probably stupid to map digits, vi isn't your mother.
 *
 * The way this works is that the TXT_MAPNODIGIT causes term_key to return the
 * end-of-digit without "looking" at the next character, i.e. leaving it as the
 * user entered it.  Presumably, the next term_key call will tell us how the
 * user wants it handled.
 *
 * There is one more complication.  Users might map keys to digits, and, as
 * it's described above, the commands "map g 1G|d2g" would return the keys
 * "d2<end-of-digits>1G", when the user probably wanted "d21<end-of-digits>G".
 * So, if a map starts off with a digit we continue as before, otherwise, we
 * pretend that we haven't mapped the character and return <end-of-digits>.
 *
 * Now that that's out of the way, let's talk about Energizer Bunny macros.
 * It's easy to create macros that expand to a loop, e.g. map x 3x.  It's
 * fairly easy to detect this example, because it's all internal to term_key.
 * If we're expanding a macro and it gets big enough, at some point we can
 * assume it's looping and kill it.  The examples that are tough are the ones
 * where the parser is involved, e.g. map x "ayyx"byy.  We do an expansion
 * on 'x', and get "ayyx"byy.  We then return the first 4 characters, and then
 * find the looping macro again.  There is no way that we can detect this
 * without doing a full parse of the command, because the character that might
 * cause the loop (in this case 'x') may be a literal character, e.g. the map
 * map x "ayy"xyy"byy is perfectly legal and won't cause a loop.
 *
 * Historic vi tried to detect looping macros by disallowing obvious cases in
 * the map command, maps that that ended with the same letter as they started
 * (which wrongly disallowed "map x 'x"), and detecting macros that expanded
 * too many times before keys were returned to the command parser.  It didn't
 * get many (most?) of the tricky cases right, however, and it was certainly
 * possible to create macros that ran forever.  And, even if it did figure out
 * what was going on, the user was usually tossed into ex mode.  Finally, any
 * changes made before vi realized that the macro was recursing were left in
 * place.  This implementation counts how many times each input character has
 * been mapped.  If it reaches some arbitrary value, we flush all mapped keys
 * and return an error.
 *
 * XXX
 * The final issue is recovery.  It would be possible to undo all of the work
 * that was done by the macro if we entered a record into the log so that we
 * knew when the macro started, and, in fact, this might be worth doing at some
 * point.  Given that this might make the log grow unacceptably (consider that
 * cursor keys are done with maps), for now we leave any changes made in place.
 */
enum input
term_key(sp, chp, flags)
	SCR *sp;
	CH *chp;
	u_int flags;
{
	enum input rval;
	struct timeval t, *tp;
	CHAR_T ch;
	GS *gp;
	IBUF *tty;
	SEQ *qp;
	int cmap, ispartial, nr, itear;

	gp = sp->gp;
	tty = gp->tty;

	/*
	 * If the queue is empty, read more keys in.  Since no timeout is
	 * requested, s_key_read will either return an error or will read
	 * some number of characters.
	 */
loop:	if (tty->cnt == 0) {
		if (term_read_grow(sp, tty))
			return (INP_ERR);
		if (rval = sp->s_key_read(sp, &nr, NULL))
			return (rval);
		/*
		 * If there's something on the mode line that we wanted
		 * the user to see, they just entered a character so we
		 * can presume they saw it.
		 */
		if (F_ISSET(sp, S_UPDATE_MODE))
			F_CLR(sp, S_UPDATE_MODE);
	}

	/* If no limit on remaps, set it up so the user can interrupt. */
	itear = O_ISSET(sp, O_REMAPMAX) ? 0 : !intr_init(sp);

	/* If the key is mappable and should be mapped, look it up. */
	if (!(tty->chf[tty->next] & CH_NOMAP) &&
	    LF_ISSET(TXT_MAPCOMMAND | TXT_MAPINPUT)) {
		/* Set up timeout value. */
		if (O_ISSET(sp, O_TIMEOUT)) {
			tp = &t;
			t.tv_sec = O_VAL(sp, O_KEYTIME) / 10;
			t.tv_usec = (O_VAL(sp, O_KEYTIME) % 10) * 100000L;
		} else
			tp = NULL;

		/* Get the next key. */
newmap:		ch = tty->ch[tty->next];
		if (ch < MAX_BIT_SEQ && !bit_test(gp->seqb, ch))
			goto nomap;

		/* Search the map. */
remap:		qp = seq_find(sp, NULL, &tty->ch[tty->next], tty->cnt,
		    LF_ISSET(TXT_MAPCOMMAND) ? SEQ_COMMAND : SEQ_INPUT,
		    &ispartial);

		/*
		 * If get a partial match, read more characters and retry
		 * the map.  If no characters read, return the characters
		 * unmapped.
		 */
		if (ispartial) {
			if (term_read_grow(sp, tty)) {
				rval = INP_ERR;
				goto ret;
			}
			if (rval = sp->s_key_read(sp, &nr, tp))
				goto ret;
			if (nr)
				goto remap;
			goto nomap;
		}

		/* If no map, return the character. */
		if (qp == NULL)
			goto nomap;

		/*
		 * If looking for the end of a digit string, and the first
		 * character of the map is it, pretend we haven't seen the
		 * character.
		 */
		if (LF_ISSET(TXT_MAPNODIGIT) &&
		    qp->output != NULL && !isdigit(qp->output[0]))
			goto not_digit_ch;

		/*
		 * Only permit a character to be remapped a certain number
		 * of times before we figure that it's not going to finish.
		 */
		if (O_ISSET(sp, O_REMAPMAX)) {
			if ((cmap = tty->cmap[tty->next]) > MAX_MAP_COUNT)
				goto flush;
		} else if (F_ISSET(sp, S_INTERRUPTED)) {
flush:			term_map_flush(sp, "Character remapped too many times");
			rval = INP_ERR;
			goto ret;
		} else
			cmap = 0;

		/* Delete the mapped characters from the queue. */
		QREM_HEAD(tty, qp->ilen);

		/* If keys mapped to nothing, go get more. */
		if (qp->output == NULL)
			goto loop;

		/* If remapping characters, push the character on the queue. */
		if (O_ISSET(sp, O_REMAP)) {
			if (term_push(sp, qp->output, qp->olen, ++cmap, 0)) {
				rval = INP_ERR;
				goto ret;
			}
			goto newmap;
		}

		/* Else, push the characters on the queue and return one. */
		if (term_push(sp, qp->output, qp->olen, 0, CH_NOMAP)) {
			rval = INP_ERR;
			goto ret;
		}
	}

nomap:	ch = tty->ch[tty->next];
	if (LF_ISSET(TXT_MAPNODIGIT) && !isdigit(ch)) {
not_digit_ch:	chp->ch = CH_NOT_DIGIT;
		chp->value = 0;
		chp->flags = 0;
		rval = INP_OK;
		goto ret;
	}

	/* Fill in the return information. */
	chp->ch = ch;
	chp->flags = tty->chf[tty->next];
	chp->value = KEY_VAL(sp, ch);

	/* Delete the character from the queue. */
	QREM_HEAD(tty, 1);
	rval = INP_OK;

ret:	if (itear)
		intr_end(sp);
	return (rval);
}

/*
 * term_ab_flush --
 *	Flush any abbreviated keys.
 */
void
term_ab_flush(sp, msg)
	SCR *sp;
	char *msg;
{
	IBUF *tty;

	tty = sp->gp->tty;
	if (!tty->cnt || !(tty->chf[tty->next] & CH_ABBREVIATED))
		return;
	do {
		QREM_HEAD(tty, 1);
	} while (tty->cnt && tty->chf[tty->next] & CH_ABBREVIATED);
	msgq(sp, M_ERR, "%s: keys flushed.", msg);
}

/*
 * term_map_flush --
 *	Flush any mapped keys.
 */
void
term_map_flush(sp, msg)
	SCR *sp;
	char *msg;
{
	IBUF *tty;

	tty = sp->gp->tty;
	if (!tty->cnt || !tty->cmap[tty->next])
		return;
	do {
		QREM_HEAD(tty, 1);
	} while (tty->cnt && tty->cmap[tty->next]);
	msgq(sp, M_ERR, "%s: keys flushed.", msg);
}

/*
 * term_user_key --
 *	Get the next key, but require the user enter one.
 */
enum input
term_user_key(sp, chp)
	SCR *sp;
	CH *chp;
{
	enum input rval;
	IBUF *tty;
	int nr;

	/*
	 * Read any keys the user has waiting.  Make the race
	 * condition as short as possible.
	 */
	if (rval = term_key_queue(sp))
		return (rval);

	/* Wait and read another key. */
	if (rval = sp->s_key_read(sp, &nr, NULL))
		return (rval);

	/* Fill in the return information. */
	tty = sp->gp->tty;
	chp->ch = tty->ch[tty->next + (tty->cnt - 1)];
	chp->flags = 0;
	chp->value = KEY_VAL(sp, chp->ch);

	QREM_TAIL(tty, 1);
	return (INP_OK);
}

/*
 * term_key_queue --
 *	Read the keys off of the terminal queue until it's empty.
 */
static int
term_key_queue(sp)
	SCR *sp;
{
	enum input rval;
	struct timeval t;
	IBUF *tty;
	int nr;

	t.tv_sec = 0;
	t.tv_usec = 0;
	for (tty = sp->gp->tty;;) {
		if (term_read_grow(sp, tty))
			return (INP_ERR);
		if (rval = sp->s_key_read(sp, &nr, &t))
			return (rval);
		if (nr == 0)
			break;
	}
	return (INP_OK);
}

/*
 * __key_val --
 *	Fill in the value for a key.  This routine is the backup
 *	for the KEY_VAL() macro.
 */
int
__key_val(sp, ch)
	SCR *sp;
	ARG_CHAR_T ch;
{
	KEYLIST k, *kp;

	k.ch = ch;
	kp = bsearch(&k, keylist, nkeylist, sizeof(keylist[0]), keycmp);
	return (kp == NULL ? K_NOTUSED : kp->value);
}

/*
 * __term_read_grow --
 *	Grow the terminal queue.  This routine is the backup for
 *	the term_read_grow() macro.
 */
static int
__term_read_grow(sp, tty, add)
	SCR *sp;
	IBUF *tty;
	int add;
{
	size_t new_nelem, olen;

	new_nelem = tty->nelem + add;
	olen = tty->nelem * sizeof(tty->ch[0]);
	BINC_RET(sp, tty->ch, olen, new_nelem * sizeof(tty->ch[0]));

	olen = tty->nelem * sizeof(tty->chf[0]);
	BINC_RET(sp, tty->chf, olen, new_nelem * sizeof(tty->chf[0]));

	olen = tty->nelem * sizeof(tty->cmap[0]);
	BINC_RET(sp, tty->cmap, olen, new_nelem * sizeof(tty->cmap[0]));

	tty->nelem = new_nelem;
	return (0);
}

static int
keycmp(ap, bp)
	const void *ap, *bp;
{
	return (((KEYLIST *)ap)->ch - ((KEYLIST *)bp)->ch);
}