X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=blobdiff_plain;f=terminal.c;h=7570a63b16743fd54b5b8f17cda4c0466ce6c10b;hb=f004bcca17a789356c32527a396b68b71a773db2;hp=ee88974b56326bca9cfcd0d602ef2761011562c6;hpb=7d394fc9e9c705770f6bde26b67df1b00ea82c64;p=PuTTY.git

diff --git a/terminal.c b/terminal.c
index ee88974b..7570a63b 100644
--- a/terminal.c
+++ b/terminal.c
@@ -98,6 +98,7 @@ const wchar_t sel_nl[] = SEL_NL;
 static void resizeline(Terminal *, termline *, int);
 static termline *lineptr(Terminal *, int, int, int);
 static void unlineptr(termline *);
+static void check_line_size(Terminal *, termline *);
 static void do_paint(Terminal *, Context, int);
 static void erase_lots(Terminal *, int, int, int);
 static int find_last_nonempty_line(Terminal *, tree234 *);
@@ -1053,8 +1054,25 @@ static termline *lineptr(Terminal *term, int y, int lineno, int screen)
     }
     assert(line != NULL);
 
-    resizeline(term, line, term->cols);
-    /* FIXME: should we sort the compressed scrollback out here? */
+    /*
+     * Here we resize lines to _at least_ the right length, but we
+     * don't truncate them. Truncation is done as a side effect of
+     * modifying the line.
+     *
+     * The point of this policy is to try to arrange that resizing the
+     * terminal window repeatedly - e.g. successive steps in an X11
+     * opaque window-resize drag, or resizing as a side effect of
+     * retiling by tiling WMs such as xmonad - does not throw away
+     * data gratuitously. Specifically, we want a sequence of resize
+     * operations with no terminal output between them to have the
+     * same effect as a single resize to the ultimate terminal size,
+     * and also (for the case in which xmonad narrows a window that's
+     * scrolling things) we want scrolling up new text at the bottom
+     * of a narrowed window to avoid truncating lines further up when
+     * the window is re-widened.
+     */
+    if (term->cols > line->cols)
+        resizeline(term, line, term->cols);
 
     return line;
 }
@@ -1062,6 +1080,22 @@ static termline *lineptr(Terminal *term, int y, int lineno, int screen)
 #define lineptr(x) (lineptr)(term,x,__LINE__,FALSE)
 #define scrlineptr(x) (lineptr)(term,x,__LINE__,TRUE)
 
+/*
+ * Coerce a termline to the terminal's current width. Unlike the
+ * optional resize in lineptr() above, this is potentially destructive
+ * of text, since it can shrink as well as grow the line.
+ *
+ * We call this whenever a termline is actually going to be modified.
+ * Helpfully, putting a single call to this function in check_boundary
+ * deals with _nearly_ all such cases, leaving only a few things like
+ * bulk erase and ESC#8 to handle separately.
+ */
+static void check_line_size(Terminal *term, termline *line)
+{
+    if (term->cols != line->cols)      /* trivial optimisation */
+        resizeline(term, line, term->cols);
+}
+
 static void term_schedule_tblink(Terminal *term);
 static void term_schedule_cblink(Terminal *term);
 
@@ -1316,7 +1350,7 @@ void term_pwron(Terminal *term, int clear)
 {
     power_on(term, clear);
     if (term->ldisc)		       /* cause ldisc to notice changes */
-	ldisc_send(term->ldisc, NULL, 0, 0);
+	ldisc_echoedit_update(term->ldisc);
     term->disptop = 0;
     deselect(term);
     term_update(term);
@@ -1493,12 +1527,44 @@ void term_reconfig(Terminal *term, Conf *conf)
 void term_clrsb(Terminal *term)
 {
     unsigned char *line;
+    int i;
+
+    /*
+     * Scroll forward to the current screen, if we were back in the
+     * scrollback somewhere until now.
+     */
     term->disptop = 0;
+
+    /*
+     * Clear the actual scrollback.
+     */
     while ((line = delpos234(term->scrollback, 0)) != NULL) {
 	sfree(line);            /* this is compressed data, not a termline */
     }
+
+    /*
+     * When clearing the scrollback, we also truncate any termlines on
+     * the current screen which have remembered data from a previous
+     * larger window size. Rationale: clearing the scrollback is
+     * sometimes done to protect privacy, so the user intention is
+     * specifically that we should not retain evidence of what
+     * previously happened in the terminal, and that ought to include
+     * evidence to the right as well as evidence above.
+     */
+    for (i = 0; i < term->rows; i++)
+        check_line_size(term, scrlineptr(i));
+
+    /*
+     * There are now no lines of real scrollback which can be pulled
+     * back into the screen by a resize, and no lines of the alternate
+     * screen which should be displayed as if part of the scrollback.
+     */
     term->tempsblines = 0;
     term->alt_sblines = 0;
+
+    /*
+     * Update the scrollbar to reflect the new state of the world.
+     */
     update_sbar(term);
 }
 
@@ -2281,6 +2347,7 @@ static void check_boundary(Terminal *term, int x, int y)
 	return;
 
     ldata = scrlineptr(y);
+    check_line_size(term, ldata);
     if (x == term->cols) {
 	ldata->lattr &= ~LATTR_WRAPPED2;
     } else {
@@ -2351,6 +2418,7 @@ static void erase_lots(Terminal *term,
     } else {
 	termline *ldata = scrlineptr(start.y);
 	while (poslt(start, end)) {
+            check_line_size(term, ldata);
 	    if (start.x == term->cols) {
 		if (!erase_lattr)
 		    ldata->lattr &= ~(LATTR_WRAPPED | LATTR_WRAPPED2);
@@ -2506,7 +2574,7 @@ static void toggle_mode(Terminal *term, int mode, int query, int state)
 	  case 10:		       /* DECEDM: set local edit mode */
 	    term->term_editing = state;
 	    if (term->ldisc)	       /* cause ldisc to notice changes */
-		ldisc_send(term->ldisc, NULL, 0, 0);
+		ldisc_echoedit_update(term->ldisc);
 	    break;
 	  case 25:		       /* DECTCEM: enable/disable cursor */
 	    compatibility2(OTHER, VT220);
@@ -2570,7 +2638,7 @@ static void toggle_mode(Terminal *term, int mode, int query, int state)
 	  case 12:		       /* SRM: set echo mode */
 	    term->term_echoing = !state;
 	    if (term->ldisc)	       /* cause ldisc to notice changes */
-		ldisc_send(term->ldisc, NULL, 0, 0);
+		ldisc_echoedit_update(term->ldisc);
 	    break;
 	  case 20:		       /* LNM: Return sends ... */
 	    term->cr_lf_return = state;
@@ -3293,7 +3361,7 @@ static void term_out(Terminal *term)
 		    compatibility(VT100);
 		    power_on(term, TRUE);
 		    if (term->ldisc)   /* cause ldisc to notice changes */
-			ldisc_send(term->ldisc, NULL, 0, 0);
+			ldisc_echoedit_update(term->ldisc);
 		    if (term->reset_132) {
 			if (!term->no_remote_resize)
 			    request_resize(term->frontend, 80, term->rows);
@@ -3317,6 +3385,7 @@ static void term_out(Terminal *term)
 
 			for (i = 0; i < term->rows; i++) {
 			    ldata = scrlineptr(i);
+                            check_line_size(term, ldata);
 			    for (j = 0; j < term->cols; j++) {
 				copy_termchar(ldata, j,
 					      &term->basic_erase_char);
@@ -3341,6 +3410,7 @@ static void term_out(Terminal *term)
 		    compatibility(VT100);
 		    {
 			int nlattr;
+			termline *ldata;
 
 			switch (ANSI(c, term->esc_query)) {
 			  case ANSI('3', '#'): /* DECDHL: 2*height, top */
@@ -3356,7 +3426,9 @@ static void term_out(Terminal *term)
 			    nlattr = LATTR_WIDE;
 			    break;
 			}
-			scrlineptr(term->curs.y)->lattr = nlattr;
+			ldata = scrlineptr(term->curs.y);
+                        check_line_size(term, ldata);
+                        ldata->lattr = nlattr;
 		    }
 		    break;
 		  /* GZD4: G0 designate 94-set */