terminal.c

大名鼎鼎的远程登录软件putty的Symbian版源码

	    sfree(cline);
	    line->temporary = FALSE;   /* reconstituted line is now real */
	    term->tempsblines -= 1;
	    addpos234(term->screen, line, 0);
	    term->curs.y += 1;
	    term->savecurs.y += 1;
	} else {
	    /* Add a new blank line at the bottom of the screen. */
	    line = newline(term, newcols, FALSE);
	    addpos234(term->screen, line, count234(term->screen));
	}
	term->rows += 1;
    }
    /* Do this loop to shrink the screen if newrows < rows */
    while (term->rows > newrows) {
	if (term->curs.y < term->rows - 1) {
	    /* delete bottom row, unless it contains the cursor */
	    sfree(delpos234(term->screen, term->rows - 1));
	} else {
	    /* push top row to scrollback */
	    line = delpos234(term->screen, 0);
	    addpos234(term->scrollback, compressline(line), sblen++);
	    freeline(line);
	    term->tempsblines += 1;
	    term->curs.y -= 1;
	    term->savecurs.y -= 1;
	}
	term->rows -= 1;
    }
    assert(term->rows == newrows);
    assert(count234(term->screen) == newrows);

    /* Delete any excess lines from the scrollback. */
    while (sblen > newsavelines) {
	line = delpos234(term->scrollback, 0);
	sfree(line);
	sblen--;
    }
    if (sblen < term->tempsblines)
	term->tempsblines = sblen;
    assert(count234(term->scrollback) <= newsavelines);
    assert(count234(term->scrollback) >= term->tempsblines);
    term->disptop = 0;

    /* Make a new displayed text buffer. */
    newdisp = snewn(newrows, termline *);
    for (i = 0; i < newrows; i++) {
	newdisp[i] = newline(term, newcols, FALSE);
	for (j = 0; j < newcols; j++)
	    newdisp[i]->chars[i].attr = ATTR_INVALID;
    }
    if (term->disptext) {
	for (i = 0; i < oldrows; i++)
	    freeline(term->disptext[i]);
    }
    sfree(term->disptext);
    term->disptext = newdisp;
    term->dispcursx = term->dispcursy = -1;

    /* Make a new alternate screen. */
    newalt = newtree234(NULL);
    for (i = 0; i < newrows; i++) {
	line = newline(term, newcols, TRUE);
	addpos234(newalt, line, i);
    }
    if (term->alt_screen) {
	while (NULL != (line = delpos234(term->alt_screen, 0)))
	    freeline(line);
	freetree234(term->alt_screen);
    }
    term->alt_screen = newalt;
    term->alt_sblines = 0;

    term->tabs = sresize(term->tabs, newcols, unsigned char);
    {
	int i;
	for (i = (term->cols > 0 ? term->cols : 0); i < newcols; i++)
	    term->tabs[i] = (i % 8 == 0 ? TRUE : FALSE);
    }

    /* Check that the cursor positions are still valid. */
    if (term->savecurs.y < 0)
	term->savecurs.y = 0;
    if (term->savecurs.y >= newrows)
	term->savecurs.y = newrows - 1;
    if (term->curs.y < 0)
	term->curs.y = 0;
    if (term->curs.y >= newrows)
	term->curs.y = newrows - 1;
    if (term->curs.x >= newcols)
	term->curs.x = newcols - 1;
    term->alt_x = term->alt_y = 0;
    term->wrapnext = term->alt_wnext = FALSE;

    term->rows = newrows;
    term->cols = newcols;
    term->savelines = newsavelines;

    swap_screen(term, save_alt_which, FALSE, FALSE);

    update_sbar(term);
    term_update(term);
    if (term->resize_fn)
	term->resize_fn(term->resize_ctx, term->cols, term->rows);
}

/*
 * Hand a function and context pointer to the terminal which it can
 * use to notify a back end of resizes.
 */
void term_provide_resize_fn(Terminal *term,
			    void (*resize_fn)(void *, int, int),
			    void *resize_ctx)
{
    term->resize_fn = resize_fn;
    term->resize_ctx = resize_ctx;
    if (term->cols > 0 && term->rows > 0)
	resize_fn(resize_ctx, term->cols, term->rows);
}

/* Find the bottom line on the screen that has any content.
 * If only the top line has content, returns 0.
 * If no lines have content, return -1.
 */ 
static int find_last_nonempty_line(Terminal * term, tree234 * screen)
{
    int i;
    for (i = count234(screen) - 1; i >= 0; i--) {
	termline *line = index234(screen, i);
	int j;
	for (j = 0; j < line->cols; j++)
	    if (!termchars_equal(&line->chars[j], &term->erase_char))
		break;
	if (j != line->cols) break;
    }
    return i;
}

/*
 * Swap screens. If `reset' is TRUE and we have been asked to
 * switch to the alternate screen, we must bring most of its
 * configuration from the main screen and erase the contents of the
 * alternate screen completely. (This is even true if we're already
 * on it! Blame xterm.)
 */
static void swap_screen(Terminal *term, int which, int reset, int keep_cur_pos)
{
    int t;
    tree234 *ttr;

    if (!which)
	reset = FALSE;		       /* do no weird resetting if which==0 */

    if (which != term->alt_which) {
	term->alt_which = which;

	ttr = term->alt_screen;
	term->alt_screen = term->screen;
	term->screen = ttr;
	term->alt_sblines = find_last_nonempty_line(term, term->alt_screen) + 1;
	t = term->curs.x;
	if (!reset && !keep_cur_pos)
	    term->curs.x = term->alt_x;
	term->alt_x = t;
	t = term->curs.y;
	if (!reset && !keep_cur_pos)
	    term->curs.y = term->alt_y;
	term->alt_y = t;
	t = term->marg_t;
	if (!reset) term->marg_t = term->alt_t;
	term->alt_t = t;
	t = term->marg_b;
	if (!reset) term->marg_b = term->alt_b;
	term->alt_b = t;
	t = term->dec_om;
	if (!reset) term->dec_om = term->alt_om;
	term->alt_om = t;
	t = term->wrap;
	if (!reset) term->wrap = term->alt_wrap;
	term->alt_wrap = t;
	t = term->wrapnext;
	if (!reset) term->wrapnext = term->alt_wnext;
	term->alt_wnext = t;
	t = term->insert;
	if (!reset) term->insert = term->alt_ins;
	term->alt_ins = t;
	t = term->cset;
	if (!reset) term->cset = term->alt_cset;
	term->alt_cset = t;
	t = term->utf;
	if (!reset) term->utf = term->alt_utf;
	term->alt_utf = t;
	t = term->sco_acs;
	if (!reset) term->sco_acs = term->alt_sco_acs;
	term->alt_sco_acs = t;
    }

    if (reset && term->screen) {
	/*
	 * Yes, this _is_ supposed to honour background-colour-erase.
	 */
	erase_lots(term, FALSE, TRUE, TRUE);
    }
}

/*
 * Update the scroll bar.
 */
static void update_sbar(Terminal *term)
{
    int nscroll = sblines(term);
    set_sbar(term->frontend, nscroll + term->rows,
	     nscroll + term->disptop, term->rows);
}

/*
 * Check whether the region bounded by the two pointers intersects
 * the scroll region, and de-select the on-screen selection if so.
 */
static void check_selection(Terminal *term, pos from, pos to)
{
    if (poslt(from, term->selend) && poslt(term->selstart, to))
	deselect(term);
}

/*
 * Scroll the screen. (`lines' is +ve for scrolling forward, -ve
 * for backward.) `sb' is TRUE if the scrolling is permitted to
 * affect the scrollback buffer.
 */
static void scroll(Terminal *term, int topline, int botline, int lines, int sb)
{
    termline *line;
    int i, seltop, olddisptop, shift;

    if (topline != 0 || term->alt_which != 0)
	sb = FALSE;

    olddisptop = term->disptop;
    shift = lines;
    if (lines < 0) {
	while (lines < 0) {
	    line = delpos234(term->screen, botline);
            resizeline(term, line, term->cols);
	    for (i = 0; i < term->cols; i++)
		copy_termchar(line, i, &term->erase_char);
	    line->lattr = LATTR_NORM;
	    addpos234(term->screen, line, topline);

	    if (term->selstart.y >= topline && term->selstart.y <= botline) {
		term->selstart.y++;
		if (term->selstart.y > botline) {
		    term->selstart.y = botline + 1;
		    term->selstart.x = 0;
		}
	    }
	    if (term->selend.y >= topline && term->selend.y <= botline) {
		term->selend.y++;
		if (term->selend.y > botline) {
		    term->selend.y = botline + 1;
		    term->selend.x = 0;
		}
	    }

	    lines++;
	}
    } else {
	while (lines > 0) {
	    line = delpos234(term->screen, topline);
	    cc_check(line);	       /* XXX-REMOVE-BEFORE-RELEASE */
	    if (sb && term->savelines > 0) {
		int sblen = count234(term->scrollback);
		/*
		 * We must add this line to the scrollback. We'll
		 * remove a line from the top of the scrollback if
		 * the scrollback is full.
		 */
		if (sblen == term->savelines) {
		    unsigned char *cline;

		    sblen--;
		    cline = delpos234(term->scrollback, 0);
		    sfree(cline);
		} else
		    term->tempsblines += 1;

		addpos234(term->scrollback, compressline(line), sblen);

		/* now `line' itself can be reused as the bottom line */

		/*
		 * If the user is currently looking at part of the
		 * scrollback, and they haven't enabled any options
		 * that are going to reset the scrollback as a
		 * result of this movement, then the chances are
		 * they'd like to keep looking at the same line. So
		 * we move their viewpoint at the same rate as the
		 * scroll, at least until their viewpoint hits the
		 * top end of the scrollback buffer, at which point
		 * we don't have the choice any more.
		 * 
		 * Thanks to Jan Holmen Holsten for the idea and
		 * initial implementation.
		 */
		if (term->disptop > -term->savelines && term->disptop < 0)
		    term->disptop--;
	    }
            resizeline(term, line, term->cols);
	    for (i = 0; i < term->cols; i++)
		copy_termchar(line, i, &term->erase_char);
	    line->lattr = LATTR_NORM;
	    addpos234(term->screen, line, botline);

	    /*
	     * If the selection endpoints move into the scrollback,
	     * we keep them moving until they hit the top. However,
	     * of course, if the line _hasn't_ moved into the
	     * scrollback then we don't do this, and cut them off
	     * at the top of the scroll region.
	     * 
	     * This applies to selstart and selend (for an existing
	     * selection), and also selanchor (for one being
	     * selected as we speak).
	     */
	    seltop = sb ? -term->savelines : topline;

	    if (term->selstate != NO_SELECTION) {
		if (term->selstart.y >= seltop &&
		    term->selstart.y <= botline) {
		    term->selstart.y--;
		    if (term->selstart.y < seltop) {
			term->selstart.y = seltop;
			term->selstart.x = 0;
		    }
		}
		if (term->selend.y >= seltop && term->selend.y <= botline) {
		    term->selend.y--;
		    if (term->selend.y < seltop) {
			term->selend.y = seltop;
			term->selend.x = 0;
		    }
		}
		if (term->selanchor.y >= seltop &&
		    term->selanchor.y <= botline) {
		    term->selanchor.y--;
		    if (term->selanchor.y < seltop) {
			term->selanchor.y = seltop;
			term->selanchor.x = 0;
		    }
		}
	    }

	    lines--;
	}
    }
#ifdef OPTIMISE_SCROLL
    shift += term->disptop - olddisptop;
    if (shift < term->rows && shift > -term->rows && shift != 0)
	scroll_display(term, topline, botline, shift);
#endif /* OPTIMISE_SCROLL */
}

#ifdef OPTIMISE_SCROLL
/*
 * Add a scroll of a region on the screen into the pending scroll list.
 * `lines' is +ve for scrolling forward, -ve for backward.
 *
 * If the scroll is on the same area as the last scroll in the list,
 * merge them.
 */
static void save_scroll(Terminal *term, int topline, int botline, int lines)
{
    struct scrollregion *newscroll;
    if (term->scrolltail &&
	term->scrolltail->topline == topline && 
	term->scrolltail->botline == botline) {
	term->scrolltail->lines += lines;
    } else {
	newscroll = snew(struct scrollregion);
	newscroll->topline = topline;
	newscroll->botline = botline;
	newscroll->lines = lines;
	newscroll->next = NULL;

	if (!term->scrollhead)
	    term->scrollhead = newscroll;
	else
	    term->scrolltail->next = newscroll;
	term->scrolltail = newscroll;
    }
}

/*
 * Scroll the physical display, and our conception of it in disptext.
 */
static void scroll_display(Terminal *term, int topline, int botline, int lines)
{
    int distance, nlines, i, j;

    distance = lines > 0 ? lines : -lines;
    nlines = botline - topline + 1 - distance;
    if (lines > 0) {
	for (i = 0; i < nlines; i++)
	    for (j = 0; j < term->cols; j++)
		copy_termchar(term->disptext[start+i], j,
			      term->disptext[start+i+distance]->chars+j);
	if (term->dispcursy >= 0 &&
	    term->dispcursy >= topline + distance &&
	    term->dispcursy < topline + distance + nlines)
	    term->dispcursy -= distance;
	for (i = 0; i < distance; i++)
	    for (j = 0; j < term->cols; j++)
		term->disptext[start+nlines+i]->chars[j].attr |= ATTR_INVALID;
    } else {
	for (i = nlines; i-- ;)
	    for (j = 0; j < term->cols; j++)
		copy_termchar(term->disptext[start+i+distance], j,
			      term->disptext[start+i]->chars+j);
	if (term->dispcursy >= 0 &&
	    term->dispcursy >= topline &&
	    term->dispcursy < topline + nlines)
	    term->dispcursy += distance;
	for (i = 0; i < distance; i++)
	    for (j = 0; j < term->cols; j++)
		term->disptext[start+i]->chars[j].attr |= ATTR_INVALID;
    }
    save_scroll(term, topline, botline, lines);
}
#endif /* OPTIMISE_SCROLL */

/*
 * Move the cursor to a given position, clipping at boundaries. We
 * may or may not want to clip at the scroll margin: marg_clip is 0
 * not to, 1 to disallow _passing_ the margins, and 2 to disallow
 * even _being_ outside the margins.
 */
static void move(Terminal *term, int x, int y, int marg_clip)
{
    if (x < 0)
	x = 0;
    if (x >= term->cols)
	x = term->cols - 1;
    if (marg_clip) {
	if ((term->curs.y >= term->marg_t || marg_clip == 2) &&
	    y < term->marg_t)
	    y = term->marg_t;
	if ((term->curs.y <= term->marg_b || marg_clip == 2) &&
	    y > term->marg_b)
	    y = term->marg_b;
    }
    if (y < 0)
	y = 0;
    if (y >= term->rows)
	y = term->rows - 1;
    term->curs.x = x;
    term->curs.y = y;
    term->wrapnext = FALSE;
}

/*
 * Save or restore the cursor and SGR mode.
 */