perf tools: Check existence of _get_comp_words_by_ref when bash completing

The '_get_comp_words_by_ref' function is available from the bash
completion v1.2 so that earlier version emits following warning:

  $ perf re<TAB>_get_comp_words_by_ref: command not found

Use older '_get_cword' method when the above function doesn't exist.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1349191294-6926-2-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 13 insertions, 2 deletions

diff --git a/tools/perf/bash_completion b/tools/perf/bash_completion
index 1958fa539d0..3d48cee1b5e 100644
--- a/tools/perf/bash_completion
+++ b/tools/perf/bash_completion
@@ -1,12 +1,23 @@
 # perf completion
 
+function_exists()
+{
+        declare -F $1 > /dev/null
+        return $?
+}
+
 have perf &&
 _perf()
 {
-        local cur cmd
+        local cur prev cmd
 
         COMPREPLY=()
-        _get_comp_words_by_ref cur prev
+        if function_exists _get_comp_words_by_ref; then
+                _get_comp_words_by_ref cur prev
+        else
+                cur=$(_get_cword)
+                prev=${COMP_WORDS[COMP_CWORD-1]}
+        fi
 
         cmd=${COMP_WORDS[0]}