perf hists: Add helper functions for hierarchy mode

The rb_hierarchy_{next,prev,last} functions are to traverse all hist
entries in a hierarchy.  They will be used by various function which
supports hierarchy output.

As the rb_hierarchy_next() is used to traverse the whole hierarchy, it
sometime needs to visit entries regardless of current folding state.  So
add enum hierarchy_move_dir and pass it to __rb_hierarchy_next() for
those cases.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Pekka Enberg <penberg@kernel.org>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1456326830-30456-5-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/util/hist.h b/tools/perf/util/hist.h
index 044419b3..5690906 100644
--- a/tools/perf/util/hist.h
+++ b/tools/perf/util/hist.h
@@ -418,4 +418,20 @@
 
 void perf_hpp_list__init(struct perf_hpp_list *list);
 
+enum hierarchy_move_dir {
+	HMD_NORMAL,
+	HMD_FORCE_SIBLING,
+	HMD_FORCE_CHILD,
+};
+
+struct rb_node *rb_hierarchy_last(struct rb_node *node);
+struct rb_node *__rb_hierarchy_next(struct rb_node *node,
+				    enum hierarchy_move_dir hmd);
+struct rb_node *rb_hierarchy_prev(struct rb_node *node);
+
+static inline struct rb_node *rb_hierarchy_next(struct rb_node *node)
+{
+	return __rb_hierarchy_next(node, HMD_NORMAL);
+}
+
 #endif	/* __PERF_HIST_H */