bash: use for-each-ref format 'refname:short'

Using this format simplifies the code for completing refs and (in some
cases) improves performance significantly.

For repositories like the current git.git (with more than 200 refs)
there is no real performance difference, but for a repository with 2000
refs the total time needed to complete the refs is reduced by ~25% (from
around 400ms to around 305ms).

Signed-off-by: SZEDER Gábor <szeder@ira.uka.de>
Acked-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash
index d3fb6ae..fccb499 100755 (executable)
--- a/contrib/completion/git-completion.bash
+++ b/contrib/completion/git-completion.bash
@@ -154,11 +154,8 @@ __git_heads ()
 {
        local cmd i is_hash=y dir="$(__gitdir "$1")"
        if [ -d "$dir" ]; then
-               for i in $(git --git-dir="$dir" \
-                       for-each-ref --format='%(refname)' \
-                       refs/heads ); do
-                       echo "${i#refs/heads/}"
-               done
+               git --git-dir="$dir" for-each-ref --format='%(refname:short)' \
+                       refs/heads
                return
        fi
        for i in $(git ls-remote "$1" 2>/dev/null); do
@@ -175,11 +172,8 @@ __git_tags ()
 {
        local cmd i is_hash=y dir="$(__gitdir "$1")"
        if [ -d "$dir" ]; then
-               for i in $(git --git-dir="$dir" \
-                       for-each-ref --format='%(refname)' \
-                       refs/tags ); do
-                       echo "${i#refs/tags/}"
-               done
+               git --git-dir="$dir" for-each-ref --format='%(refname:short)' \
+                       refs/tags
                return
        fi
        for i in $(git ls-remote "$1" 2>/dev/null); do
@@ -197,16 +191,8 @@ __git_refs ()
        local cmd i is_hash=y dir="$(__gitdir "$1")"
        if [ -d "$dir" ]; then
                if [ -e "$dir/HEAD" ]; then echo HEAD; fi
-               for i in $(git --git-dir="$dir" \
-                       for-each-ref --format='%(refname)' \
-                       refs/tags refs/heads refs/remotes); do
-                       case "$i" in
-                               refs/tags/*)    echo "${i#refs/tags/}" ;;
-                               refs/heads/*)   echo "${i#refs/heads/}" ;;
-                               refs/remotes/*) echo "${i#refs/remotes/}" ;;
-                               *)              echo "$i" ;;
-                       esac
-               done
+               git --git-dir="$dir" for-each-ref --format='%(refname:short)' \
+                       refs/tags refs/heads refs/remotes
                return
        fi
        for i in $(git ls-remote "$dir" 2>/dev/null); do