[RFC/PATCH] completion: git: add fast mode

[Felipe Contreras <felipe.contreras@gmail.com>]

Using the official Git Bash completion script the completion is
blazingly fast.

We can optionally enable this mode if Git's official Bash completion script is
specified by the user.

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
---

This patch is just to show how merging the gitfast/git zsh
wrapper/git-completion might look like.

 Completion/Unix/Command/_git | 125 +++++++++++++++++++++++++++++++++++
 1 file changed, 125 insertions(+)

diff --git a/Completion/Unix/Command/_git b/Completion/Unix/Command/_git
index 81a060e4d..9a307faad 100644
--- a/Completion/Unix/Command/_git
+++ b/Completion/Unix/Command/_git
@@ -39,6 +39,104 @@
 
 # TODO: There is still undocumented configurability in here.
 
+zstyle -s ":completion:*:*:git:*" bash-script git_bash_script
+
+if [ -n "$git_bash_script" ]; then
+
+local old_complete="$functions[complete]"
+functions[complete]=:
+COMP_WORDBREAKS=':'
+GIT_SOURCING_ZSH_COMPLETION=y . "$git_bash_script"
+functions[complete]="$old_complete"
+
+__gitcompadd ()
+{
+	compadd -Q -p "${2-}" -S "${3- }" ${@[4,-1]} -- ${=1} && _ret=0
+}
+
+__gitcomp ()
+{
+	emulate -L zsh
+
+	local cur_="${3-$cur}"
+
+	[[ "$cur_" == *= ]] && return
+
+	local c IFS=$' \t\n' sfx
+	for c in ${=1}; do
+		if [[ $c == "--" ]]; then
+			[[ "$cur_" == --no-* ]] && continue
+			__gitcompadd "--no-..."
+			break
+		fi
+
+		if [[ -z "${4-}" ]]; then
+			case $c in
+			*=) c="${c%=}"; sfx="=" ;;
+			*.) sfx="" ;;
+			*) sfx=" " ;;
+			esac
+		else
+			sfx="$4"
+		fi
+		__gitcompadd "$c" "${2-}" "$sfx" -q
+	done
+}
+
+__gitcomp_nl ()
+{
+	emulate -L zsh
+
+	IFS=$'\n' __gitcompadd "$1" "${2-}" "${4- }"
+}
+
+__gitcomp_file ()
+{
+	emulate -L zsh
+
+	compadd -f -p "${2-}" -- ${(f)1} && _ret=0
+}
+
+__gitcomp_direct ()
+{
+	__gitcomp_nl "$1" "" "" ""
+}
+
+__gitcomp_file_direct ()
+{
+	__gitcomp_file "$1" ""
+}
+
+__gitcomp_nl_append ()
+{
+	__gitcomp_nl "$@"
+}
+
+__gitcomp_direct_append ()
+{
+	__gitcomp_direct "$@"
+}
+
+__gitbash_complete_func ()
+{
+	local _ret=1
+	local cur cword prev
+
+	cur=${words[CURRENT]}
+	prev=${words[CURRENT-1]}
+	let cword=CURRENT-1
+
+	if (( $+functions[$1] )); then
+		compset -P '*[=:]'
+		emulate ksh -c $1
+		return _ret
+	else
+		return 1
+	fi
+}
+
+fi
+
 # HIGH-LEVEL COMMANDS (PORCELAIN)
 
 # Main Porcelain Commands
@@ -768,6 +866,11 @@ _git-diff () {
 
   case $state in
     (from-to-file)
+      if [ -n "$git_bash_script" ]; then
+        __gitbash_complete_func __git_complete_revlist && ret=0
+        return ret
+      fi
+
       # If "--" is part of $opt_args, this means it was specified before any
       # $words arguments. This means that no heads are specified in front, so
       # we need to complete *changed* files only.
@@ -953,6 +1056,11 @@ _git-format-patch () {
 
   case $state in
     (commit-or-commit-range)
+      if [ -n "$git_bash_script" ]; then
+        __gitbash_complete_func __git_complete_revlist && ret=0
+        return ret
+      fi
+
       if [[ -n ${opt_args[(I)--root]} ]]; then
         __git_commits && ret=0
       else
@@ -1183,6 +1291,13 @@ _git-log () {
     '1: :->first-commit-ranges-or-files' \
     '*: :->commit-ranges-or-files' && ret=0
 
+  if [ -n "$git_bash_script" ]; then
+    if [ -n "$state" ]; then
+      __gitbash_complete_func __git_complete_revlist && ret=0
+      return ret
+    fi
+  fi
+
   case $state in
     (first-commit-ranges-or-files)
       if [[ -n ${opt_args[(I)--]} ]]; then
@@ -1676,6 +1791,11 @@ _git-shortlog () {
       fi
       ;;
     (commit-range-or-file)
+      if [ -n "$git_bash_script" ]; then
+        __gitbash_complete_func __git_complete_revlist && ret=0
+        return ret
+      fi
+
       case $CURRENT in
         (1)
           if [[ -n ${opt_args[(I)--]} ]]; then
@@ -5412,6 +5532,11 @@ _git-rev-list () {
 
   case $state in
     (commit-or-path)
+      if [ -n "$git_bash_script" ]; then
+        __gitbash_complete_func __git_complete_revlist && ret=0
+        return ret
+      fi
+
       # TODO: What paths should we be completing here?
       if [[ -n ${opt_args[(I)--]} ]]; then
         __git_cached_files && ret=0
-- 
2.29.2