git-subtree.sh

   1 #!/bin/bash
   2 #
   3 # git-subtree.sh: split/join git repositories in subdirectories of this one
   4 #
   5 # Copyright (c) 2009 Avery Pennarun <apenwarr@gmail.com>
   6 #
   7 OPTS_SPEC="\
   8 git subtree split <revisions> -- <subdir>
   9 git subtree merge
  10
  11 git subtree does foo and bar!
  12 --
  13 h,help   show the help
  14 q        quiet
  15 v        verbose
  16 "
  17 eval $(echo "$OPTS_SPEC" | git rev-parse --parseopt -- "$@" || echo exit $?)
  18 . git-sh-setup
  19 require_work_tree
  20
  21 quiet=
  22 command=
  23
  24 debug()
  25 {
  26         if [ -z "$quiet" ]; then
  27                 echo "$@" >&2
  28         fi
  29 }
  30
  31 assert()
  32 {
  33         if "$@"; then
  34                 :
  35         else
  36                 die "assertion failed: " "$@"
  37         fi
  38 }
  39
  40
  41 #echo "Options: $*"
  42
  43 while [ $# -gt 0 ]; do
  44         opt="$1"
  45         shift
  46         case "$opt" in
  47                 -q) quiet=1 ;;
  48                 --) break ;;
  49         esac
  50 done
  51
  52 command="$1"
  53 shift
  54 case "$command" in
  55         split|merge) ;;
  56         *) die "Unknown command '$command'" ;;
  57 esac
  58
  59 revs=$(git rev-parse --default HEAD --revs-only "$@") || exit $?
  60 dirs="$(git rev-parse --sq --no-revs --no-flags "$@")" || exit $?
  61
  62 #echo "dirs is {$dirs}"
  63 eval $(echo set -- $dirs)
  64 if [ "$#" -ne 1 ]; then
  65         die "Must provide exactly one subtree dir (got $#)"
  66 fi
  67 dir="$1"
  68
  69 debug "command: {$command}"
  70 debug "quiet: {$quiet}"
  71 debug "revs: {$revs}"
  72 debug "dir: {$dir}"
  73
  74 cache_setup()
  75 {
  76         cachedir="$GIT_DIR/subtree-cache/$$"
  77         rm -rf "$cachedir" || die "Can't delete old cachedir: $cachedir"
  78         mkdir -p "$cachedir" || die "Can't create new cachedir: $cachedir"
  79         debug "Using cachedir: $cachedir" >&2
  80         echo "$cachedir"
  81 }
  82
  83 cache_get()
  84 {
  85         for oldrev in $*; do
  86                 if [ -r "$cachedir/$oldrev" ]; then
  87                         read newrev <"$cachedir/$oldrev"
  88                         echo $newrev
  89                 fi
  90         done
  91 }
  92
  93 cache_set()
  94 {
  95         oldrev="$1"
  96         newrev="$2"
  97         if [ -e "$cachedir/$oldrev" ]; then
  98                 die "cache for $oldrev already exists!"
  99         fi
 100         echo "$newrev" >"$cachedir/$oldrev"
 101 }
 102
 103 cmd_split()
 104 {
 105         debug "Splitting $dir..."
 106         cache_setup || exit $?
 107
 108         git rev-list --reverse --parents $revs -- "$dir" |
 109         while read rev parents; do
 110                 newparents=$(cache_get $parents)
 111                 debug
 112                 debug "Processing commit: $rev / $newparents"
 113
 114                 git ls-tree $rev -- "$dir" |
 115                 while read mode type tree name; do
 116                         assert [ "$name" = "$dir" ]
 117                         debug "  tree is: $tree"
 118                         p=""
 119                         for parent in $newparents; do
 120                                 p="$p -p $parent"
 121                         done
 122                         newrev=$(echo synthetic | git commit-tree $tree $p) \
 123                                 || die "Can't create new commit for $rev / $tree"
 124                         echo "  newrev is: $newrev"
 125                         cache_set $rev $newrev
 126                 done || exit $?
 127         done || exit $?
 128
 129         exit 0
 130 }
 131
 132 cmd_merge()
 133 {
 134         die "merge command not implemented yet"
 135 }
 136
 137 "cmd_$command"