From ef2c29d5d4974cc773149d368488a6d8a0fcc1fc Mon Sep 17 00:00:00 2001
From: Tomas Janousek <tomi@nomi.cz>
Date: Wed, 11 Nov 2020 14:44:47 +0000
Subject: [PATCH] [bash-completion] Optimize __fzf_orig_completion_filter
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Commit d4ad4a25 slowed loading of completion.bash significantly (on my
laptop from 10 ms to 30 ms), then 54891d11 improved that (to 20 ms) but
it still stands out as the heavy part of my .bashrc.

Rewriting __fzf_orig_completion_filter to pure bash without forking to
sed/awk brings this back under 10 ms.

before:

    $ HISTFILE=/tmp/bashhist hyperfine 'bash --rcfile shell/completion.bash -i'
    Benchmark #1: bash --rcfile shell/completion.bash -i
      Time (mean ± σ):      21.2 ms ±   0.3 ms    [User: 24.9 ms, System: 6.4 ms]
      Range (min … max):    20.7 ms …  23.3 ms    132 runs

after:

    $ HISTFILE=/tmp/bashhist hyperfine 'bash --rcfile shell/completion.bash -i'
    Benchmark #1: bash --rcfile shell/completion.bash -i
      Time (mean ± σ):       9.6 ms ±   0.3 ms    [User: 8.0 ms, System: 2.2 ms]
      Range (min … max):     9.3 ms …  11.4 ms    298 runs

Fixes: d4ad4a25db5f ("[bash-completion] Fix default alias/variable completion")
Fixes: 54891d11e09d ("[bash-completion] Minor optimization")
---
 shell/completion.bash | 24 ++++++++++++++++--------
 1 file changed, 16 insertions(+), 8 deletions(-)

diff --git a/shell/completion.bash b/shell/completion.bash
index 1af1769..b8c32ab 100644
--- a/shell/completion.bash
+++ b/shell/completion.bash
@@ -46,9 +46,19 @@ __fzf_comprun() {
   fi
 }
 
-__fzf_orig_completion_filter() {
-  sed '/ -F/!d; / _fzf/d; s/^\(.*-F\) *\([^ ]*\).* \([^ ]*\)$/export _fzf_orig_completion_\3="\1 %s \3 #\2"; [[ "\1" = *" -o nospace "* ]] \&\& [[ ! "$__fzf_nospace_commands" = *" \3 "* ]] \&\& __fzf_nospace_commands="$__fzf_nospace_commands \3 ";/' |
-  awk -F= '{OFS = FS} {gsub(/[^A-Za-z0-9_= ;]/, "_", $1);}1'
+__fzf_orig_completion() {
+  local l comp f cmd
+  while read -r l; do
+    if [[ "$l" =~ ^(.*\ -F)\ *([^ ]*).*\ ([^ ]*)$ ]]; then
+      comp="${BASH_REMATCH[1]}"
+      f="${BASH_REMATCH[2]}"
+      cmd="${BASH_REMATCH[3]}"
+      export "_fzf_orig_completion_${cmd//[^A-Za-z0-9_]/_}=${comp} %s ${cmd} #${f}"
+      if [[ "$l" = *" -o nospace "* ]] && [[ ! "$__fzf_nospace_commands" = *" $cmd "* ]]; then
+        __fzf_nospace_commands="$__fzf_nospace_commands $cmd "
+      fi
+    fi
+  done
 }
 
 _fzf_opts_completion() {
@@ -137,7 +147,7 @@ _fzf_handle_dynamic_completion() {
     ret=$?
     # _completion_loader may not have updated completion for the command
     if [ "$(complete -p "$orig_cmd" 2> /dev/null)" != "$orig_complete" ]; then
-      eval "$(complete | command grep " -F.* $orig_cmd$" | __fzf_orig_completion_filter)"
+      __fzf_orig_completion < <(complete -p "$orig_cmd" 2> /dev/null)
       if [[ "$__fzf_nospace_commands" = *" $orig_cmd "* ]]; then
         eval "${orig_complete/ -F / -o nospace -F }"
       else
@@ -306,9 +316,7 @@ a_cmds="
   svn tar unzip zip"
 
 # Preserve existing completion
-eval "$(complete |
-  sed -E "/ ($(echo $d_cmds $a_cmds | sed 's/ /|/g; s/+/\\+/g'))$/"'!d' |
-  __fzf_orig_completion_filter)"
+__fzf_orig_completion < <(complete -p $d_cmds $a_cmds 2> /dev/null)
 
 if type _completion_loader > /dev/null 2>&1; then
   _fzf_completion_loader=1
@@ -353,7 +361,7 @@ _fzf_setup_completion() {
     return 1
   fi
   shift
-  eval "$(complete -p "$@" 2> /dev/null | __fzf_orig_completion_filter)"
+  __fzf_orig_completion < <(complete -p "$@" 2> /dev/null)
   for cmd in "$@"; do
     case "$kind" in
       dir)   __fzf_defc "$cmd" "$fn" "-o nospace -o dirnames" ;;