implemented the ^W command for refreshing the screen in loops, for sleeping and also the CTRL+L immediate editing command

* ^W can be added to loops in order to view progress in interactive mode.
  It also sleeps for a given number of milliseconds (10ms by default).
* In batch mode it is therefore the sleep command.
* Since CTRL+W is an immediate editing command, you will usually type it Caret+W.
  ASCII 23 however will also be accepted.
* While ^W only updates the screen, you can force a complete redraw by pressing CTRL+L.
  This is what most terminal applications use for redrawing.
  It will make it harder to insert ASCII 12, but this is seldom necessary since it
  is a form feed.
  ^L (ASCII 12 and the upcaret variant ) is still a whitespace character and therefore treated as a NOP.
* DEC TECO had CTRL+W as the refresh immediate editing command.
  Video TECO uses <ET> as a regular command for refreshign in loops.
  I'd rather keep ET reserved as a potential terminal configuration command
  as in DEC TECO, though.

7 files changed, 107 insertions, 25 deletions

diff --git a/doc/sciteco.7.template b/doc/sciteco.7.template
index 965e203..3bf8d2e 100644
--- a/doc/sciteco.7.template
+++ b/doc/sciteco.7.template
@@ -680,6 +680,16 @@ work as an immediate editing command in the GUI or as a signal
 dispatched from an associated console or from another process.
 T}
 T{
+.SCITECO_TOPIC ^L redraw
+Redraw
+T};12;^L;T{
+Everywhere
+T};T{
+Enforces a complete redraw of the entire window.
+This is useful when the display becomes corrupted,
+especially when using the Curses UI.
+T}
+T{
 .SCITECO_TOPIC interrupt
 Interrupt
 T};3;^C;T{
diff --git a/src/cmdline.c b/src/cmdline.c
index 605af73..1f12c7b 100644
--- a/src/cmdline.c
+++ b/src/cmdline.c
@@ -472,6 +472,11 @@ teco_state_process_edit_cmd(teco_machine_t *ctx, teco_machine_t *parent_ctx, gun
 		raise(SIGTSTP);
 		return TRUE;
 #endif
+
+	case TECO_CTL_KEY('L'):
+		/* causes a complete screen redraw */
+		teco_interface_refresh(TRUE);
+		return TRUE;
 	}
 
 	teco_interface_popup_clear();
diff --git a/src/core-commands.c b/src/core-commands.c
index a2d3c92..c71ee95 100644
--- a/src/core-commands.c
+++ b/src/core-commands.c
@@ -1605,6 +1605,46 @@ teco_state_control_time(teco_machine_main_t *ctx, GError **error)
 	}
 }
 
+/*$ ^W refresh sleep delay wait
+ * [n]^W -- Wait and refresh screen
+ *
+ * First sleep <n> milliseconds before refreshing the view,
+ * i.e. drawing it.
+ * By default it sleeps for 10ms.
+ * This can be added to loops to make progress visible
+ * in interactive mode.
+ * In batch mode this command is useful as a sleep command.
+ * Sleeps can of course be interrupted with CTRL+C.
+ *
+ * Since CTRL+W is an immediate editing command, you may
+ * have to type this command in upcaret mode.
+ * To enforce a complete screen redraw you can also
+ * press CTRL+L.
+ */
+static void
+teco_state_control_refresh(teco_machine_main_t *ctx, GError **error)
+{
+	teco_int_t ms;
+
+	if (!teco_expressions_pop_num_calc(&ms, 10, error))
+		return;
+
+	while (ms > 0 && !teco_interface_is_interrupted()) {
+		/*
+		 * UNIX' usleep() would also be interrupted by
+		 * SIGINT, but polling for interruptions is
+		 * probably precise enough.
+		 * We need this as a fallback anyway.
+		 */
+		g_usleep(MIN(ms*1000, TECO_POLL_INTERVAL));
+		ms -= TECO_POLL_INTERVAL/1000;
+	}
+
+	teco_interface_unfold();
+	teco_interface_ssm(SCI_SCROLLCARET, 0, 0);
+	teco_interface_refresh(FALSE);
+}
+
 static teco_state_t *
 teco_state_control_input(teco_machine_main_t *ctx, gunichar chr, GError **error)
 {
@@ -1647,7 +1687,8 @@ teco_state_control_input(teco_machine_main_t *ctx, gunichar chr, GError **error)
 		['Y']  = {&teco_state_start, teco_state_control_last_range},
 		['S']  = {&teco_state_start, teco_state_control_last_length},
 		['T']  = {&teco_state_start, teco_state_control_typeout,
-		          .modifier_colon = 1}
+		          .modifier_colon = 1},
+		['W']  = {&teco_state_start, teco_state_control_refresh}
 	};
 
 	/*
diff --git a/src/interface-curses/interface.c b/src/interface-curses/interface.c
index d92eade..381c188 100644
--- a/src/interface-curses/interface.c
+++ b/src/interface-curses/interface.c
@@ -134,7 +134,6 @@ teco_console_ctrl_handler(DWORD type)
 
 static gint teco_xterm_version(void) G_GNUC_UNUSED;
 
-static void teco_interface_refresh(void);
 static gint teco_interface_blocking_getch(void);
 
 #define UNNAMED_FILE "(Unnamed)"
@@ -924,7 +923,7 @@ teco_interface_getch(gboolean widechar)
 	if (!teco_interface.cmdline_window) /* batch mode */
 		return teco_interface_stdio_getch(widechar);
 
-	teco_interface_refresh();
+	teco_interface_refresh(FALSE);
 
 	/*
 	 * Signal that we accept input by drawing a real cursor in the message bar.
@@ -1819,8 +1818,8 @@ teco_interface_is_interrupted(void)
  * filtering out CTRL+C.
  * It's currently necessary as a fallback e.g. for PDCURSES_GUI or XCurses.
  *
- * NOTE: Theoretically, this can be optimized by doing wgetch() only every X
- * microseconds like on Gtk+.
+ * NOTE: Theoretically, this can be optimized by doing wgetch() only every
+ * TECO_POLL_INTERVAL microseconds like on Gtk+.
  * But this turned out to slow things down, at least on PDCurses/WinGUI.
  */
 gboolean
@@ -1848,9 +1847,16 @@ teco_interface_is_interrupted(void)
 
 #endif
 
-static void
-teco_interface_refresh(void)
+void
+teco_interface_refresh(gboolean force)
 {
+	if (!teco_interface.cmdline_window)
+		/* batch mode */
+		return;
+
+	if (G_UNLIKELY(force))
+		clearok(curscr, TRUE);
+
 	/*
 	 * Info window is updated very often which is very
 	 * costly, especially when using PDC_set_title(),
@@ -2124,7 +2130,7 @@ teco_interface_event_loop_iter(void)
 		 * in the ^KMOUSE macro, allowing dot to be outside of the view.
 		 */
 		teco_interface_unfold();
-		teco_interface_refresh();
+		teco_interface_refresh(FALSE);
 		return;
 #endif
 
@@ -2183,7 +2189,7 @@ teco_interface_event_loop_iter(void)
 	teco_interface_unfold();
 	teco_interface_ssm(SCI_SCROLLCARET, 0, 0);
 
-	teco_interface_refresh();
+	teco_interface_refresh(FALSE);
 }
 
 gboolean
@@ -2199,7 +2205,7 @@ teco_interface_event_loop(GError **error)
 	teco_interface_cmdline_update(&empty_cmdline);
 	teco_interface_msg_clear();
 	teco_interface_ssm(SCI_SCROLLCARET, 0, 0);
-	teco_interface_refresh();
+	teco_interface_refresh(FALSE);
 
 #ifdef EMCURSES
 	PDC_emscripten_set_handler(teco_interface_event_loop_iter, TRUE);
diff --git a/src/interface-gtk/interface.c b/src/interface-gtk/interface.c
index ae1dd74..dcf3660 100644
--- a/src/interface-gtk/interface.c
+++ b/src/interface-gtk/interface.c
@@ -77,12 +77,6 @@ static gboolean teco_interface_window_delete_cb(GtkWidget *widget, GdkEventAny *
 static gboolean teco_interface_sigterm_handler(gpointer user_data) G_GNUC_UNUSED;
 static gchar teco_interface_get_ansi_key(GdkEventKey *event);
 
-/**
- * Interval between polling for keypresses.
- * In other words, this is the maximum latency to detect CTRL+C interruptions.
- */
-#define TECO_POLL_INTERVAL	100000 /* microseconds */
-
 #define UNNAMED_FILE		"(Unnamed)"
 
 #define USER_CSS_FILE		".teco_css"
@@ -437,10 +431,6 @@ teco_interface_getch_commit_cb(GtkIMContext *context, gchar *str, gpointer user_
 	gtk_main_quit();
 }
 
-/*
- * FIXME: Redundancies with teco_interface_handle_keypress()
- * FIXME: Report function keys
- */
 static gboolean
 teco_interface_getch_input_cb(GtkWidget *widget, GdkEvent *event, gpointer user_data)
 {
@@ -865,6 +855,27 @@ teco_interface_is_interrupted(void)
 	return teco_interrupted != FALSE;
 }
 
+void
+teco_interface_refresh(gboolean force)
+{
+	if (!gtk_main_level()) /* batch mode */
+		return;
+
+	if (G_UNLIKELY(force))
+		gtk_widget_queue_draw(teco_interface.window);
+
+	GdkWindow *top_window = gdk_window_get_toplevel(gtk_widget_get_window(teco_interface.window));
+	gdk_window_thaw_updates(top_window);
+
+	/*
+	 * FIXME: Why do we need two iterations to see any updates?
+	 */
+	for (gint i = 0; i < 2; i++)
+		gtk_main_iteration_do(FALSE);
+
+	gdk_window_freeze_updates(top_window);
+}
+
 static void
 teco_interface_set_css_variables(teco_view_t *view)
 {
@@ -942,7 +953,7 @@ teco_interface_set_css_variables(teco_view_t *view)
 }
 
 static void
-teco_interface_refresh(gboolean current_view_changed)
+teco_interface_update(gboolean current_view_changed)
 {
 	/*
 	 * The styles configured via Scintilla might change
@@ -1290,7 +1301,7 @@ teco_interface_event_loop(GError **error)
 	                                          GTK_STYLE_PROVIDER(user_css_provider),
 	                                          GTK_STYLE_PROVIDER_PRIORITY_USER);
 
-	teco_interface_refresh(TRUE);
+	teco_interface_update(TRUE);
 
 	gtk_widget_show_all(teco_interface.window);
 	/* don't show popup by default */
@@ -1512,7 +1523,7 @@ teco_interface_input_cb(GtkWidget *widget, GdkEvent *event, gpointer user_data)
 		}
 		teco_interrupted = FALSE;
 
-		teco_interface_refresh(teco_interface_current_view != last_view);
+		teco_interface_update(teco_interface_current_view != last_view);
 		/* always expand folds, even after mouse clicks */
 		teco_interface_unfold();
 		/*
@@ -1597,7 +1608,7 @@ teco_interface_popup_clicked_cb(GtkWidget *popup, gchar *str, gulong len, gpoint
 	teco_interface_popup_clear();
 	teco_interface_cmdline_update(&teco_cmdline);
 
-	teco_interface_refresh(teco_interface_current_view != last_view);
+	teco_interface_update(teco_interface_current_view != last_view);
 }
 
 static gboolean
diff --git a/src/interface.h b/src/interface.h
index f22c023..02af8a2 100644
--- a/src/interface.h
+++ b/src/interface.h
@@ -41,6 +41,12 @@
  * feature.
  */
 
+/**
+ * Interval between polling for keypresses (if necessary).
+ * In other words, this is the maximum latency to detect CTRL+C interruptions.
+ */
+#define TECO_POLL_INTERVAL 100000 /* microseconds */
+
 /** @protected */
 extern teco_view_t *teco_interface_current_view;
 
@@ -179,6 +185,9 @@ void teco_interface_stdio_msg(teco_msg_t type, const gchar *str, gsize len);
 /** @protected */
 teco_int_t teco_interface_stdio_getch(gboolean widechar);
 
+/** @protected */
+void teco_interface_refresh(gboolean force);
+
 /** @pure */
 void teco_interface_cleanup(void);
 
diff --git a/tests/testsuite.at b/tests/testsuite.at
index 78e6f48..7fecc45 100644
--- a/tests/testsuite.at
+++ b/tests/testsuite.at
@@ -357,7 +357,7 @@ AT_CLEANUP
 
 AT_SETUP([Timestamps])
 # TODO: Test the date (^B) and time (^H and :^H) variants as well.
-TE_CHECK([[::^HUa ::^H-Qa"<(0/0)']], 0, ignore, ignore)
+TE_CHECK([[::^HUt 100^W (::^H-Qt)-100"<(0/0)']], 0, ignore, ignore)
 AT_CLEANUP
 
 AT_SETUP([Program version])