perf report: Enable the runtime switching of perf data file

This is for tui browser only. This patch will check the returned key of
tui hists browser, if it's K_SWITH_INPUT_DATA, then recreate a session
for the new selected data file.

V2: Move the setup_brower() before the "repeat" jump point.
Signed-off-by: Feng Tang <feng.tang@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1359873501-24541-2-git-send-email-feng.tang@intel.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/builtin-report.c

@@ -468,9 +468,17 @@ static int __cmd_report(struct perf_report *rep)
 
 	if (use_browser > 0) {
 		if (use_browser == 1) {
-			perf_evlist__tui_browse_hists(session->evlist, help,
+			ret = perf_evlist__tui_browse_hists(session->evlist,
+							help,
 							NULL,
 							&session->header.env);
+			/*
+			 * Usually "ret" is the last pressed key, and we only
+			 * care if the key notifies us to switch data file.
+			 */
+			if (ret != K_SWITCH_INPUT_DATA)
+				ret = 0;
+
 		} else if (use_browser == 2) {
 			perf_evlist__gtk_browse_hists(session->evlist, help,
 						      NULL);
@@ -708,6 +716,16 @@ int cmd_report(int argc, const char **argv, const char *prefix __maybe_unused)
 		else
 			input_name = "perf.data";
 	}
+
+	if (strcmp(input_name, "-") != 0)
+		setup_browser(true);
+	else {
+		use_browser = 0;
+		perf_hpp__column_enable(PERF_HPP__OVERHEAD);
+		perf_hpp__init();
+	}
+
+repeat:
 	session = perf_session__new(input_name, O_RDONLY,
 				    report.force, false, &report.tool);
 	if (session == NULL)
@@ -733,14 +751,6 @@ int cmd_report(int argc, const char **argv, const char *prefix __maybe_unused)
 
 	}
 
-	if (strcmp(input_name, "-") != 0)
-		setup_browser(true);
-	else {
-		use_browser = 0;
-		perf_hpp__column_enable(PERF_HPP__OVERHEAD);
-		perf_hpp__init();
-	}
-
 	setup_sorting(report_usage, options);
 
 	/*
@@ -809,6 +819,12 @@ int cmd_report(int argc, const char **argv, const char *prefix __maybe_unused)
 	}
 
 	ret = __cmd_report(&report);
+	if (ret == K_SWITCH_INPUT_DATA) {
+		perf_session__delete(session);
+		goto repeat;
+	} else
+		ret = 0;
+
 error:
 	perf_session__delete(session);
 	return ret;