Documentation: minor cleanups to branch/checkout wording

diff --git a/git-filter-branch.sh b/git-filter-branch.sh
old mode 100755 (executable)
new mode 100644 (file)
index 9d61b7f..a2fcebc
--- a/git-filter-branch.sh
+++ b/git-filter-branch.sh
@@ -119,6 +119,10 @@
 #      attached, the rewritten tag won't have it. Sorry. (It is by
 #      definition impossible to preserve signatures at any rate, though.)
 #
+# --subdirectory-filter DIRECTORY:: Only regard the history, as seen by
+#      the given subdirectory. The result will contain that directory as
+#      its project root.
+#
 # EXAMPLE USAGE
 # -------------
 # Suppose you want to remove a file (containing confidential information
@@ -174,6 +178,14 @@
 #
 #      git-filter-branch ... new-H C..H --not D
 #      git-filter-branch ... new-H D..H --not C
+#
+# To move the whole tree into a subdirectory, or remove it from there:
+#
+# git-filter-branch --index-filter \
+#      'git-ls-files -s | sed "s-\t-&newsubdir/-" |
+#              GIT_INDEX_FILE=$GIT_INDEX_FILE.new \
+#                      git-update-index --index-info &&
+#       mv $GIT_INDEX_FILE.new $GIT_INDEX_FILE' directorymoved
 
 # Testsuite: TODO
 
@@ -222,11 +234,6 @@ set_ident () {
        echo "[ -n \"\$GIT_${uid}_NAME\" ] || export GIT_${uid}_NAME=\"\${GIT_${uid}_EMAIL%%@*}\""
 }
 
-# list all parent's object names for a given commit
-get_parents () {
-       git-rev-list -1 --parents "$1" | sed "s/^[0-9a-f]*//"
-}
-
 tempdir=.git-rewrite
 filter_env=
 filter_tree=
@@ -235,6 +242,7 @@ filter_parent=
 filter_msg=cat
 filter_commit='git-commit-tree "$@"'
 filter_tag_name=
+filter_subdir=
 while case "$#" in 0) usage;; esac
 do
        case "$1" in
@@ -280,6 +288,9 @@ do
        --tag-name-filter)
                filter_tag_name="$OPTARG"
                ;;
+       --subdirectory-filter)
+               filter_subdir="$OPTARG"
+               ;;
        *)
                usage
                ;;
@@ -301,9 +312,10 @@ case "$GIT_DIR" in
 /*)
        ;;
 *)
-       export GIT_DIR="$(pwd)/../../$GIT_DIR"
+       GIT_DIR="$(pwd)/../../$GIT_DIR"
        ;;
 esac
+export GIT_DIR GIT_WORK_TREE=.
 
 export GIT_INDEX_FILE="$(pwd)/../index"
 git-read-tree # seed the index file
@@ -313,17 +325,31 @@ ret=0
 
 mkdir ../map # map old->new commit ids for rewriting parents
 
-git-rev-list --reverse --topo-order --default HEAD "$@" >../revs
+case "$filter_subdir" in
+"")
+       git-rev-list --reverse --topo-order --default HEAD \
+               --parents "$@"
+       ;;
+*)
+       git-rev-list --reverse --topo-order --default HEAD \
+               --parents --full-history "$@" -- "$filter_subdir"
+esac > ../revs
 commits=$(cat ../revs | wc -l | tr -d " ")
 
 test $commits -eq 0 && die "Found nothing to rewrite"
 
 i=0
-while read commit; do
+while read commit parents; do
        i=$(($i+1))
        printf "$commit ($i/$commits) "
 
-       git-read-tree -i -m $commit
+       case "$filter_subdir" in
+       "")
+               git-read-tree -i -m $commit
+               ;;
+       *)
+               git-read-tree -i -m $commit:"$filter_subdir"
+       esac
 
        export GIT_COMMIT=$commit
        git-cat-file commit "$commit" >../commit
@@ -347,7 +373,7 @@ while read commit; do
        eval "$filter_index" < /dev/null
 
        parentstr=
-       for parent in $(get_parents $commit); do
+       for parent in $parents; do
                for reparent in $(map "$parent"); do
                        parentstr="$parentstr -p $reparent"
                done
@@ -362,7 +388,7 @@ while read commit; do
                tee ../map/$commit
 done <../revs
 
-src_head=$(tail -n 1 ../revs)
+src_head=$(tail -n 1 ../revs | sed -e 's/ .*//')
 target_head=$(head -n 1 ../map/$src_head)
 case "$target_head" in
 '')