perf completion: Factor out compgen stuff

compgen is a bash-builtin; factor out the invocations into a separate
function to give us a chance to override it with a zsh equivalent in
future patches.
Signed-off-by: NRamkumar Ramachandra <artagnon@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Link: http://lkml.kernel.org/r/1384704807-15779-3-git-send-email-artagnon@gmail.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/bash_completion

@@ -89,6 +89,11 @@ __ltrim_colon_completions()
 	fi
 }
 
+__perfcomp ()
+{
+	COMPREPLY=( $( compgen -W "$1" -- "$2" ) )
+}
+
 __perf_main ()
 {
 	local cmd
@@ -99,23 +104,23 @@ __perf_main ()
 	# List perf subcommands or long options
 	if [ $cword -eq 1 ]; then
 		if [[ $cur == --* ]]; then
-			COMPREPLY=( $( compgen -W '--help --version \
+			__perfcomp '--help --version \
 			--exec-path --html-path --paginate --no-pager \
-			--perf-dir --work-tree --debugfs-dir' -- "$cur" ) )
+			--perf-dir --work-tree --debugfs-dir' -- "$cur"
 		else
 			cmds=$($cmd --list-cmds)
-			COMPREPLY=( $( compgen -W '$cmds' -- "$cur" ) )
+			__perfcomp "$cmds" "$cur"
 		fi
 	# List possible events for -e option
 	elif [[ $prev == "-e" && "${words[1]}" == @(record|stat|top) ]]; then
 		evts=$($cmd list --raw-dump)
-		COMPREPLY=( $( compgen -W '$evts' -- "$cur" ) )
+		__perfcomp "$evts" "$cur"
 		__ltrim_colon_completions $cur
 	# List long option names
 	elif [[ $cur == --* ]];  then
 		subcmd=${words[1]}
 		opts=$($cmd $subcmd --list-opts)
-		COMPREPLY=( $( compgen -W '$opts' -- "$cur" ) )
+		__perfcomp "$opts" "$cur"
 	fi
 }