trace-cmd: Add bash completion for "-{e|p|l|n|g}"

"-e", "-p" and "-{l|n|g}" are frequently used parameters in many
sub-commands, adding auto-completion support for them.

It may be very slow when triggering "-{l|n|g}" auto completion. However,
it's better than nothing.

Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 46 insertions, 9 deletions

diff --git a/trace-cmd.bash b/trace-cmd.bash
index e7e4673d..3b76af2d 100644
--- a/trace-cmd.bash
+++ b/trace-cmd.bash
@@ -1,13 +1,50 @@
 _trace_cmd_complete()
 {
-    local sub_cmd_list
-    sub_cmd_list=$(trace-cmd --help 2>/dev/null | \
-                          grep " - " | sed 's/^ *//; s/ -.*//')
-    COMPREPLY=()
-    prev="${COMP_WORDS[COMP_CWORD-1]}"
-    cur="${COMP_WORDS[COMP_CWORD]}"
-    if [[ "$prev" == "trace-cmd" ]]; then
-        COMPREPLY=( $(compgen -W "${sub_cmd_list}" -- ${cur} ))
-    fi
+    local cur=""
+    local prev=""
+
+    # Not to use COMP_WORDS to avoid buggy behavior of Bash when
+    # handling with words including ":", like:
+    #
+    # prev="${COMP_WORDS[COMP_CWORD-1]}"
+    # cur="${COMP_WORDS[COMP_CWORD]}"
+    #
+    # Instead, we use _get_comp_words_by_ref() magic.
+    _get_comp_words_by_ref -n : cur prev
+
+    case "$prev" in
+        trace-cmd)
+            local cmds=$(trace-cmd --help 2>/dev/null | \
+                                grep " - " | sed 's/^ *//; s/ -.*//')
+            COMPREPLY=( $(compgen -W "${cmds}" -- "${cur}") )
+            ;;
+        -e)
+            local events=$(trace-cmd list -e)
+            local prefix=${cur%%:*}
+
+            COMPREPLY=( $(compgen -W "${events}" -- "${cur}") )
+
+            # This is still to handle the "*:*" special case
+            if [[ -n "$prefix" ]]; then
+                local reply_n=${#COMPREPLY[*]}
+                for (( i = 0; i < $reply_n; i++)); do
+                    COMPREPLY[$i]=${COMPREPLY[i]##${prefix}:}
+                done
+            fi
+            ;;
+        -p)
+            local plugins=$(trace-cmd list -p)
+            COMPREPLY=( $(compgen -W "${plugins}" -- "${cur}") )
+            ;;
+        -l|-n|-g)
+            # This is extremely slow still (may take >1sec).
+            local funcs=$(trace-cmd list -f | sed 's/ .*//')
+            COMPREPLY=( $(compgen -W "${funcs}" -- "${cur}") )
+            ;;
+        *)
+            # By default, we do not provide any hints.
+            COMPREPLY=()
+            ;;
+    esac
 }
 complete -F _trace_cmd_complete trace-cmd