X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=blobdiff_plain;f=terminal.c;h=ac8f5dff420489f1110f4887f3f13587ae0b5e41;hb=068b67d2f6e9b186b3107ebcb1e88a141b7b5ebc;hp=71b3bec676d59b9afe65d33637ebb7151d568c15;hpb=c29ab648b96aac90971303f57eb73a64325c178e;p=PuTTY.git

diff --git a/terminal.c b/terminal.c
index 71b3bec6..ac8f5dff 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);
 
@@ -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);
@@ -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 */
@@ -5896,7 +5968,7 @@ void term_mouse(Terminal *term, Mouse_Button braw, Mouse_Button bcooked,
      */
     if (raw_mouse &&
 	(term->selstate != ABOUT_TO) && (term->selstate != DRAGGING)) {
-	int encstate = 0, r, c;
+	int encstate = 0, r, c, wheel;
 	char abuf[32];
 	int len = 0;
 
@@ -5905,22 +5977,35 @@ void term_mouse(Terminal *term, Mouse_Button braw, Mouse_Button bcooked,
 	    switch (braw) {
 	      case MBT_LEFT:
 		encstate = 0x00;	       /* left button down */
+                wheel = FALSE;
 		break;
 	      case MBT_MIDDLE:
 		encstate = 0x01;
+                wheel = FALSE;
 		break;
 	      case MBT_RIGHT:
 		encstate = 0x02;
+                wheel = FALSE;
 		break;
 	      case MBT_WHEEL_UP:
 		encstate = 0x40;
+                wheel = TRUE;
 		break;
 	      case MBT_WHEEL_DOWN:
 		encstate = 0x41;
+                wheel = TRUE;
 		break;
-	      default: break;	       /* placate gcc warning about enum use */
+	      default:
+                return;
 	    }
-	    switch (a) {
+            if (wheel) {
+                /* For mouse wheel buttons, we only ever expect to see
+                 * MA_CLICK actions, and we don't try to keep track of
+                 * the buttons being 'pressed' (since without matching
+                 * click/release pairs that's pointless). */
+                if (a != MA_CLICK)
+                    return;
+            } else switch (a) {
 	      case MA_DRAG:
 		if (term->xterm_mouse == 1)
 		    return;
@@ -5937,7 +6022,8 @@ void term_mouse(Terminal *term, Mouse_Button braw, Mouse_Button bcooked,
 		    return;
 		term->mouse_is_down = braw;
 		break;
-	      default: break;	       /* placate gcc warning about enum use */
+              default:
+                return;
 	    }
 	    if (shift)
 		encstate += 0x04;