perf hists browser: Add e/c hotkeys to expand/collapse callchain for current entry

Currently we allow only to expand or collapse all entries in the browser
with 'E' or 'C' keys. Allow user to expand or collapse only current
entry in the browser with e or c key.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Joe Mario <jmario@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1484904032-11040-3-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/ui/browsers/hists.c

@@ -571,6 +571,15 @@ static void hist_browser__set_folding(struct hist_browser *browser, bool unfold)
 	ui_browser__reset_index(&browser->b);
 }
 
+static void hist_browser__set_folding_selected(struct hist_browser *browser, bool unfold)
+{
+	if (!browser->he_selection)
+		return;
+
+	hist_entry__set_folding(browser->he_selection, browser, unfold);
+	browser->b.nr_entries = hist_browser__nr_entries(browser);
+}
+
 static void ui_browser__warn_lost_events(struct ui_browser *browser)
 {
 	ui_browser__warning(browser, 4,
@@ -644,10 +653,18 @@ int hist_browser__run(struct hist_browser *browser, const char *help)
 			/* Collapse the whole world. */
 			hist_browser__set_folding(browser, false);
 			break;
+		case 'c':
+			/* Collapse the selected entry. */
+			hist_browser__set_folding_selected(browser, false);
+			break;
 		case 'E':
 			/* Expand the whole world. */
 			hist_browser__set_folding(browser, true);
 			break;
+		case 'e':
+			/* Expand the selected entry. */
+			hist_browser__set_folding_selected(browser, true);
+			break;
 		case 'H':
 			browser->show_headers = !browser->show_headers;
 			hist_browser__update_rows(browser);