[PATCH] optimize gitdiff-do script
- From
- Paul Jackson <pj@sgi.com>
- Date
- Apr 16, 2005, 23:28 UTC
- Message-ID
- <20050416232810.23430.78712.sendpatchset@sam.engr.sgi.com>
- In-Reply-To
- <20050416232749.23430.93360.sendpatchset@sam.engr.sgi.com>
Rewrite gitdiff-do so that it works with arbitrary whitespace (space, tab, newline, ...) in filenames.
Reduce number of subcommands execv'd by a third, by only calling 'rm' once, at end, not each loop.
Avoid using shell arrays; perhaps more portable.
Avoid 'echo -e' when displaying names; dont expand escape sequences in names.
Use shell noglob (-f) to minimize getdents() calls.
Simplify argument parsing and tmp file management.
Comment the nastier shell patterns.
This reduces the time by about 1/3 of what it was.
Signed-off-by: Paul Jackson <pj@sgi.com>
Index: git-pasky-0.4/gitdiff-do =================================================================== --- git-pasky-0.4.orig/gitdiff-do 2005-04-16 13:19:07.000000000 -0700 +++ git-pasky-0.4/gitdiff-do 2005-04-16 15:33:28.000000000 -0700 @@ -2,19 +2,22 @@ # # Make a diff between two GIT trees. # Copyright (c) Petr Baudis, 2005 +# Copyright (c) Paul Jackson, 2005 # # Takes two parameters identifying the two trees/commits to compare. # Empty string will be substitued to HEAD revision. # # Note that this is probably the most performance critical shell script -# in the whole GIT suite. That's also why I resorted to bash builtin -# features and stuff. -- pasky@ucw.cz +# in the whole GIT suite. # # Outputs a diff converting the first tree to the second one. +set -f # keep shell from scanning "." to expand wildcards -id1=$1; shift -id2=$1; shift +t=${TMPDIR:-/usr/tmp}/gitdiff.$$ +trap 'set +f; rm -fr $t.?; trap 0; exit 0' 0 1 2 3 15 + +id1=$1; id2=$2; shift 2 # Leaves the result in $label. mkbanner () { @@ -32,58 +35,55 @@ mkbanner () { [ "$labelapp" ] && label="$label ($labelapp)" } -t=${TMPDIR:-/usr/tmp}/gitdiff.$$ -trap 'rm -fr $t.?; trap 0; exit 0' 0 1 2 3 15 -diffdir=$t.1 -diffdir1="$diffdir/$id1" -diffdir2="$diffdir/$id2" -mkdir -p "$diffdir1" "$diffdir2" - -while [ "$1" ]; do - declare -a param - param=($1); - op=${param[0]:0:1} - mode=${param[0]:1} - type=${param[1]} - sha=${param[2]} - name=${param[3]} - - echo -e "Index: $name\n===================================================================" - - if [ "$type" = "tree" ]; then - # diff-tree will kindly diff the subdirs for us - # XXX: What about modes? - shift; continue - fi - - loc1="$diffdir1/$name"; dir1="${loc1%/*}" - loc2="$diffdir2/$name"; dir2="${loc2%/*}" - ([ -d "$dir1" ] && [ -d "$dir2" ]) || mkdir -p "$dir1" "$dir2" - - case $op in - "+") - mkbanner "$loc2" $id2 "$name" $mode $sha - diff -L "/dev/null (tree:$id1)" -L "$label" -u /dev/null "$loc2" - ;; - "-") - mkbanner "$loc1" $id1 "$name" $mode $sha - diff -L "$label" -L "/dev/null (tree:$id2)" -u "$loc1" /dev/null - ;; - "*") - modes=(${mode/->/ }); - mode1=${modes[0]}; mode2=${modes[1]} - shas=(${sha/->/ }); - sha1=${shas[0]}; sha2=${shas[1]} - mkbanner "$loc1" $id1 "$name" $mode1 $sha1; label1=$label - mkbanner "$loc2" $id2 "$name" $mode2 $sha2; label2=$label - diff -L "$label1" -L "$label2" -u "$loc1" "$loc2" - ;; - *) - echo "Unknown operator $op, ignoring delta: $1";; - esac - - rm -f "$loc1" "$loc2" - shift +for arg +do + IFS=' ' + set X$arg # X: don't let shell set see leading '+' in $arg + op="$1" + mode=${op#X?} # trim leading X? 1st two chars + type="$2" + sha="$3" + # if 4+ tabs, trim 1st 3 fields on 1st line with sed + case "$arg" in + *\ *\ *\ *\ *) + name=$(echo "$arg" | + /bin/sed '1s/[^ ]* [^ ]* [^ ]* //') + ;; + *) + name="$4" + ;; + esac + + echo "Index: $name" + echo =================================================================== + + test "$type" = "tree" && continue + + loc1=$t.1 + loc2=$t.2 + + case $op in + X+*) + mkbanner $loc2 $id2 "$name" $mode $sha + diff -L "/dev/null (tree:$id1)" -L "$label" -u /dev/null $loc2 + ;; + X-*) + mkbanner $loc1 $id1 "$name" $mode $sha + diff -L "$label" -L "/dev/null (tree:$id2)" -u $loc1 /dev/null + ;; + X\**) + mode1=${mode%->*} # trim '->' and after + mode2=${mode#*->} # trim up to and including '->' + sha1=${sha%->*} # trim '->' and after + sha2=${sha#*->} # trim up to and including '->' + + mkbanner $loc1 $id1 "$name" $mode1 $sha1; label1=$label + mkbanner $loc2 $id2 "$name" $mode2 $sha2; label2=$label + diff -L "$label1" -L "$label2" -u $loc1 $loc2 + ;; + *) + badop=$(echo $op | sed 's/.\(.\).*/\1/') + echo "Unknown operator $badop, ignoring delta: $1" + ;; + esac done - -rm -rf "$diffdir"
--
I won't rest till it's the best ...
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Paul Jackson <pj@sgi.com> 1.650.933.1373, 1.925.600.0401