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 }
  81
  82 cache_get()
  83 {
  84         for oldrev in $*; do
  85                 if [ -r "$cachedir/$oldrev" ]; then
  86                         read newrev <"$cachedir/$oldrev"
  87                         echo $newrev
  88                 fi
  89         done
  90 }
  91
  92 cache_set()
  93 {
  94         oldrev="$1"
  95         newrev="$2"
  96         if [ "$oldrev" != "latest" -a -e "$cachedir/$oldrev" ]; then
  97                 die "cache for $oldrev already exists!"
  98         fi
  99         echo "$newrev" >"$cachedir/$oldrev"
 100 }
 101
 102 copy_commit()
 103 {
 104         # We're doing to set some environment vars here, so
 105         # do it in a subshell to get rid of them safely later
 106         git log -1 --pretty=format:'%an%n%ae%n%ad%n%cn%n%ce%n%cd%n%s%n%n%b' "$1" |
 107         (
 108                 read GIT_AUTHOR_NAME
 109                 read GIT_AUTHOR_EMAIL
 110                 read GIT_AUTHOR_DATE
 111                 read GIT_COMMITTER_NAME
 112                 read GIT_COMMITTER_EMAIL
 113                 read GIT_COMMITTER_DATE
 114                 export GIT_AUTHOR_NAME GIT_AUTHOR_EMAIL GIT_AUTHOR_DATE
 115                 export GIT_COMMITTER_NAME GIT_COMMITTER_EMAIL GIT_COMMITTER_DATE
 116                 git commit-tree "$2" $3  # reads the rest of stdin
 117         ) || die "Can't copy commit $1"
 118 }
 119
 120 cmd_split()
 121 {
 122         debug "Splitting $dir..."
 123         cache_setup || exit $?
 124
 125         git rev-list --reverse --parents $revs -- "$dir" |
 126         while read rev parents; do
 127                 newparents=$(cache_get $parents)
 128                 debug
 129                 debug "Processing commit: $rev / $newparents"
 130
 131                 git ls-tree $rev -- "$dir" |
 132                 while read mode type tree name; do
 133                         assert [ "$name" = "$dir" ]
 134                         debug "  tree is: $tree"
 135                         p=""
 136                         for parent in $newparents; do
 137                                 p="$p -p $parent"
 138                         done
 139
 140                         newrev=$(copy_commit $rev $tree "$p") || exit $?
 141                         debug "  newrev is: $newrev"
 142                         cache_set $rev $newrev
 143                         cache_set latest $newrev
 144                 done || exit $?
 145         done || exit $?
 146         latest=$(cache_get latest)
 147         if [ -z "$latest" ]; then
 148                 die "No new revisions were found"
 149         fi
 150         echo $latest
 151         exit 0
 152 }
 153
 154 cmd_merge()
 155 {
 156         die "merge command not implemented yet"
 157 }
 158
 159 "cmd_$command"