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#
7OPTS_SPEC="\
8git subtree split [--rejoin] [--onto rev] <commit...> -- <path>
9git subtree merge
10
11git subtree does foo and bar!
12--
13h,help show the help
14q quiet
15v verbose
16onto= existing subtree revision to connect, if any
17rejoin merge the new branch back into HEAD
18"
19eval $(echo "$OPTS_SPEC" | git rev-parse --parseopt -- "$@" || echo exit $?)
20. git-sh-setup
21require_work_tree
22
23quiet=
24command=
25onto=
26rejoin=
27
28debug()
29{
30 if [ -z "$quiet" ]; then
31 echo "$@" >&2
32 fi
33}
34
35assert()
36{
37 if "$@"; then
38 :
39 else
40 die "assertion failed: " "$@"
41 fi
42}
43
44
45#echo "Options: $*"
46
47while [ $# -gt 0 ]; do
48 opt="$1"
49 shift
50 case "$opt" in
51 -q) quiet=1 ;;
52 --onto) onto="$1"; shift ;;
53 --rejoin) rejoin=1 ;;
54 --) break ;;
55 esac
56done
57
58command="$1"
59shift
60case "$command" in
61 split|merge) ;;
62 *) die "Unknown command '$command'" ;;
63esac
64
65revs=$(git rev-parse --default HEAD --revs-only "$@") || exit $?
66dirs="$(git rev-parse --sq --no-revs --no-flags "$@")" || exit $?
67
68#echo "dirs is {$dirs}"
69eval $(echo set -- $dirs)
70if [ "$#" -ne 1 ]; then
71 die "Must provide exactly one subtree dir (got $#)"
72fi
73dir="$1"
74
75debug "command: {$command}"
76debug "quiet: {$quiet}"
77debug "revs: {$revs}"
78debug "dir: {$dir}"
79
80cache_setup()
81{
82 cachedir="$GIT_DIR/subtree-cache/$$"
83 rm -rf "$cachedir" || die "Can't delete old cachedir: $cachedir"
84 mkdir -p "$cachedir" || die "Can't create new cachedir: $cachedir"
85 debug "Using cachedir: $cachedir" >&2
86}
87
88cache_get()
89{
90 for oldrev in $*; do
91 if [ -r "$cachedir/$oldrev" ]; then
92 read newrev <"$cachedir/$oldrev"
93 echo $newrev
94 fi
95 done
96}
97
98cache_set()
99{
100 oldrev="$1"
101 newrev="$2"
102 if [ "$oldrev" != "latest_old" \
103 -a "$oldrev" != "latest_new" \
104 -a -e "$cachedir/$oldrev" ]; then
105 die "cache for $oldrev already exists!"
106 fi
107 echo "$newrev" >"$cachedir/$oldrev"
108}
109
110find_existing_splits()
111{
112 debug "Looking for prior splits..."
113 dir="$1"
114 revs="$2"
115 git log --grep="^git-subtree-dir: $dir\$" \
116 --pretty=format:'%s%n%n%b%nEND' "$revs" |
117 while read a b junk; do
118 case "$a" in
119 git-subtree-mainline:) main="$b" ;;
120 git-subtree-split:) sub="$b" ;;
121 *)
122 if [ -n "$main" -a -n "$sub" ]; then
123 debug " Prior: $main -> $sub"
124 cache_set $main $sub
125 echo "^$main^ ^$sub^"
126 main=
127 sub=
128 fi
129 ;;
130 esac
131 done
132}
133
134copy_commit()
135{
136 # We're doing to set some environment vars here, so
137 # do it in a subshell to get rid of them safely later
138 git log -1 --pretty=format:'%an%n%ae%n%ad%n%cn%n%ce%n%cd%n%s%n%n%b' "$1" |
139 (
140 read GIT_AUTHOR_NAME
141 read GIT_AUTHOR_EMAIL
142 read GIT_AUTHOR_DATE
143 read GIT_COMMITTER_NAME
144 read GIT_COMMITTER_EMAIL
145 read GIT_COMMITTER_DATE
146 export GIT_AUTHOR_NAME \
147 GIT_AUTHOR_EMAIL \
148 GIT_AUTHOR_DATE \
149 GIT_COMMITTER_NAME \
150 GIT_COMMITTER_EMAIL \
151 GIT_COMMITTER_DATE
152 git commit-tree "$2" $3 # reads the rest of stdin
153 ) || die "Can't copy commit $1"
154}
155
156merge_msg()
157{
158 dir="$1"
159 latest_old="$2"
160 latest_new="$3"
161 cat <<-EOF
162 Split '$dir/' into commit '$latest_new'
163
164 git-subtree-dir: $dir
165 git-subtree-mainline: $latest_old
166 git-subtree-split: $latest_new
167 EOF
168}
169
170cmd_split()
171{
172 debug "Splitting $dir..."
173 cache_setup || exit $?
174
175 unrevs="$(find_existing_splits "$dir" "$revs")"
176
177 git rev-list --reverse --parents $revs $unrevs -- "$dir" |
178 while read rev parents; do
179 exists=$(cache_get $rev)
180 newparents=$(cache_get $parents)
181 debug
182 debug "Processing commit: $rev / $newparents"
183
184 if [ -n "$exists" ]; then
185 debug " prior: $exists"
186 continue
187 fi
188
189 git ls-tree $rev -- "$dir" |
190 while read mode type tree name; do
191 assert [ "$name" = "$dir" ]
192 debug " tree is: $tree"
193 p=""
194 for parent in $newparents; do
195 p="$p -p $parent"
196 done
197
198 newrev=$(copy_commit $rev $tree "$p") || exit $?
199 debug " newrev is: $newrev"
200 cache_set $rev $newrev
201 cache_set latest_new $newrev
202 cache_set latest_old $rev
203 done || exit $?
204 done || exit $?
205 latest_new=$(cache_get latest_new)
206 if [ -z "$latest_new" ]; then
207 die "No new revisions were found"
208 fi
209
210 if [ -n "$rejoin" ]; then
211 debug "Merging split branch into HEAD..."
212 latest_old=$(cache_get latest_old)
213 git merge -s ours \
214 -m "$(merge_msg $dir $latest_old $latest_new)" \
215 $latest_new
216 fi
217 echo $latest_new
218 exit 0
219}
220
221cmd_merge()
222{
223 die "merge command not implemented yet"
224}
225
226"cmd_$command"