Feature: add an option to enable/disable counter and view-cleaning

doc/manual.adoc

@@ -498,6 +498,8 @@ Prompt
 |:<sha>			|Jump to a specific commit, e.g. `:2f12bcc`.
 |:<x>			|Execute the corresponding key binding, e.g. `:q`.
 |:!<command>		|Execute a system command in a pager, e.g. `:!git log -p`.
+			 Set `show-loading` to `no` to keep the previous contents visible
+			 while waiting for output and hide the elapsed-time counter.
 |:<action>		|Execute a Tig command, e.g. `:edit`.
 |:goto <rev>		|Jump to a specific revision, e.g. `:goto %(commit)^2`
 			 to go to the current commit's 2nd parent or

doc/tigrc.5.adoc

@@ -389,6 +389,12 @@ The following variables can be set:
 	Whether to automatically scroll the pager view while loading. Move the
 	cursor out of the last line to stop scrolling and back in to resume.
 
+'show-loading' (bool)::
+
+	Whether to clear a view while waiting for its first line of output and
+	show the elapsed loading time in its title. Enabled by default. When
+	disabled, the previous contents remain visible until new output arrives.
+
 'recurse-tree' (bool)::
 
 	Whether to show all files recursively in the tree view.
@@ -736,6 +742,14 @@ console output shown (as if '!' was specified). When multiple command options
 are specified their behavior is combined, e.g. "?<git commit" will prompt the
 user whether to execute the command and will exit Tig after completion.
 
+When entered at the prompt, `:!<command>` opens a pager view. By default, the
+pager is cleared before command output is read, and its title shows the elapsed
+loading time after three seconds. Set `show-loading` to `no` to retain the
+previous contents until output arrives and hide the timer. Use
+`:exec @<command>` to avoid opening the pager by running the command silently in
+the background, or `:exec +<command>` to run it synchronously and show only its
+first output line in the status bar.
+
 Note that if you want to use pipes or redirection in your commands then you
 must run them in a subshell, i.e. embed your commands in `sh -c '<commands>'`.
 

include/tig/options.h

@@ -75,6 +75,7 @@ typedef struct view_column *view_settings;
 	_(rev_filter,			bool,			VIEW_REV_FILTER) \
 	_(send_child_enter,		bool,			VIEW_NO_FLAGS) \
 	_(show_changes,			bool,			VIEW_LOG_LIKE) \
+	_(show_loading,			bool,			VIEW_NO_FLAGS) \
 	_(show_notes,			bool,			VIEW_DIFF_LIKE | VIEW_LOG_LIKE) \
 	_(show_untracked,		bool,			VIEW_LOG_LIKE) \
 	_(split_view_height,		double,			VIEW_RESET_DISPLAY) \

src/view.c

@@ -632,7 +632,7 @@ update_view(struct view *view)
 		return true;
 
 	if (!io_can_read(view->pipe, false)) {
-		if (view->lines == 0 && view_is_displayed(view)) {
+		if (opt_show_loading && view->lines == 0 && view_is_displayed(view)) {
 			time_t secs = time(NULL) - view->start_time;
 
 			if (secs > 1 && secs > view->update_secs) {
@@ -670,6 +670,8 @@ update_view(struct view *view)
 	if (!view_is_displayed(view))
 		return true;
 
+	if (redraw && !opt_show_loading)
+		werase(view->win);
 	if (redraw || view->force_redraw)
 		redraw_view_from(view, 0);
 	else
@@ -851,7 +853,8 @@ load_view(struct view *view, struct view *prev, enum open_flags flags)
 	if (view->pipe && view->lines == 0) {
 		/* Clear the old view and let the incremental updating refill
 		 * the screen. */
-		werase(view->win);
+		if (opt_show_loading)
+			werase(view->win);
 		/* Do not clear the position if it is the first view. */
 		if (view->prev && !(flags & (OPEN_RELOAD | OPEN_REFRESH))) {
 			clear_position(&view->prev_pos);

test/tigrc/save-option-test

@@ -3,6 +3,7 @@
 . libtest.sh
 
 steps "
+	:set show-loading = no
 	:save-options saved-tigrc
 "
 

tigrc

@@ -152,6 +152,7 @@ set mouse-scroll		= 3		# Number of lines to scroll via the mouse
 set mouse-wheel-cursor		= no		# Prefer moving the cursor to scrolling the view?
 set pgrp			= no		# Make tig process-group leader?
 set pager-autoscroll		= no		# Scroll the pager view automatically while loading?
+set show-loading		= yes		# Clear empty loading views and show the loading timer?
 set recurse-tree		= no		# Show all files recursively in the tree view?
 
 # User-defined commands