Fix changing colours in Change Settings.

Since ca9cd983e1, changing colour config mid-session had no effect
(until the palette was reset for some other reason). Now it does take
effect immediately (provided that the palette has not been overridden by
escape sequence -- this is new with ca9cd983e1).

This changes the semantics of palette_reset(): the only important
parameter when doing that is whether we keep escape sequence overrides
-- there's no harm in re-fetching config and platform colours whether or
not they've changed -- so that's what the parameter becomes (with a
sense that doesn't require changing the call sites). The other part of
this change is actually remembering to trigger this when the
configuration is changed.

(cherry picked from commit 1e726c94e8)

putty.h

@@ -1790,7 +1790,7 @@ void term_keyinputw(Terminal *, const wchar_t * widebuf, int len);
 void term_get_cursor_position(Terminal *term, int *x, int *y);
 void term_setup_window_titles(Terminal *term, const char *title_hostname);
 void term_notify_minimised(Terminal *term, bool minimised);
-void term_notify_palette_overrides_changed(Terminal *term);
+void term_notify_palette_changed(Terminal *term);
 void term_notify_window_pos(Terminal *term, int x, int y);
 void term_notify_window_size_pixels(Terminal *term, int x, int y);
 void term_palette_override(Terminal *term, unsigned osc4_index, rgb rgb);

terminal.c

@@ -1629,6 +1629,7 @@ void term_reconfig(Terminal *term, Conf *conf)
      * Mode, BCE, blinking text, character classes.
      */
     bool reset_wrap, reset_decom, reset_bce, reset_tblink, reset_charclass;
+    bool palette_changed = false;
     int i;
 
     reset_wrap = (conf_get_bool(term->conf, CONF_wrap_mode) !=
@@ -1674,6 +1675,29 @@ void term_reconfig(Terminal *term, Conf *conf)
         }
     }
 
+    /*
+     * Just setting conf is sufficient to cause colour setting changes
+     * to appear on the next ESC]R palette reset. But we should also
+     * check whether any colour settings have been changed, so that
+     * they can be updated immediately if they haven't been overridden
+     * by some escape sequence.
+     */
+    {
+        int i, j;
+        for (i = 0; i < CONF_NCOLOURS; i++) {
+            for (j = 0; j < 3; j++)
+                if (conf_get_int_int(term->conf, CONF_colours, i*3+j) !=
+                    conf_get_int_int(conf, CONF_colours, i*3+j))
+                    break;
+            if (j < 3) {
+                /* Actually enacting the change has to be deferred 
+                 * until the new conf is installed. */
+                palette_changed = true;
+                break;
+            }
+        }
+    }
+
     conf_free(term->conf);
     term->conf = conf_copy(conf);
 
@@ -1702,6 +1726,8 @@ void term_reconfig(Terminal *term, Conf *conf)
     if (!conf_get_str(term->conf, CONF_printer)) {
         term_print_finish(term);
     }
+    if (palette_changed)
+        term_notify_palette_changed(term);
     term_schedule_tblink(term);
     term_schedule_cblink(term);
     term_copy_stuff_from_conf(term);
@@ -1829,9 +1855,13 @@ static void palette_rebuild(Terminal *term)
     }
 }
 
-static void palette_reset(Terminal *term, bool overrides_only)
+/*
+ * Rebuild the palette from configuration and platform colours.
+ * If 'keep_overrides' set, any escape-sequence-specified overrides will
+ * remain in place.
+ */
+static void palette_reset(Terminal *term, bool keep_overrides)
 {
-    if (!overrides_only) {
     for (unsigned i = 0; i < OSC4_NCOLOURS; i++)
         term->subpalettes[SUBPAL_CONF].present[i] = true;
 
@@ -1862,13 +1892,6 @@ static void palette_reset(Terminal *term, bool overrides_only)
         col->r = col->g = col->b = shade;
     }
 
-        /*
-         * Get rid of all escape-sequence configuration.
-         */
-        for (unsigned i = 0; i < OSC4_NCOLOURS; i++)
-            term->subpalettes[SUBPAL_SESSION].present[i] = false;
-    }
-
     /*
      * Re-fetch any OS-local overrides.
      */
@@ -1876,6 +1899,14 @@ static void palette_reset(Terminal *term, bool overrides_only)
         term->subpalettes[SUBPAL_PLATFORM].present[i] = false;
     win_palette_get_overrides(term->win, term);
 
+    if (!keep_overrides) {
+        /*
+         * Get rid of all escape-sequence configuration.
+         */
+        for (unsigned i = 0; i < OSC4_NCOLOURS; i++)
+            term->subpalettes[SUBPAL_SESSION].present[i] = false;
+    }
+
     /*
      * Rebuild the composite palette.
      */
@@ -7593,7 +7624,7 @@ void term_notify_minimised(Terminal *term, bool minimised)
     term->minimised = minimised;
 }
 
-void term_notify_palette_overrides_changed(Terminal *term)
+void term_notify_palette_changed(Terminal *term)
 {
     palette_reset(term, true);
 }

windows/window.c

@@ -2394,7 +2394,7 @@ static LRESULT CALLBACK WndProc(HWND hwnd, UINT message,
 
             if (conf_get_bool(conf, CONF_system_colour) !=
                 conf_get_bool(prev_conf, CONF_system_colour))
-                term_notify_palette_overrides_changed(term);
+                term_notify_palette_changed(term);
 
             /* Pass new config data to the terminal */
             term_reconfig(term, conf);
@@ -3384,7 +3384,7 @@ static LRESULT CALLBACK WndProc(HWND hwnd, UINT message,
       case WM_SYSCOLORCHANGE:
         if (conf_get_bool(conf, CONF_system_colour)) {
             /* Refresh palette from system colours. */
-            term_notify_palette_overrides_changed(term);
+            term_notify_palette_changed(term);
             init_palette();
             /* Force a repaint of the terminal window. */
             term_invalidate(term);