basic options parsing and whatnot.

.gitignore

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+*~

git-subtree

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+git-subtree.sh

git-subtree.sh

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+#!/bin/bash
+#
+# git-subtree.sh: split/join git repositories in subdirectories of this one
+#
+# Copyright (c) 2009 Avery Pennarun <apenwarr@gmail.com>
+#
+OPTS_SPEC="\
+git subtree split <revisions> -- <subdir>
+git subtree merge 
+
+git subtree does foo and bar!
+--
+h,help   show the help
+q        quiet
+v        verbose
+"
+eval $(echo "$OPTS_SPEC" | git rev-parse --parseopt -- "$@" || echo exit $?)
+. git-sh-setup
+require_work_tree
+
+quiet=
+command=
+
+debug()
+{
+	if [ -z "$quiet" ]; then
+		echo "$@" >&2
+	fi
+}
+
+#echo "Options: $*"
+
+while [ $# -gt 0 ]; do
+	opt="$1"
+	shift
+	case "$opt" in
+		-q) quiet=1 ;;
+		--) break ;;
+	esac
+done
+
+command="$1"
+shift
+case "$command" in
+	split|merge) ;;
+	*) die "Unknown command '$command'" ;;
+esac
+
+revs=$(git rev-parse --default HEAD --revs-only "$@") || exit $?
+dirs="$(git rev-parse --sq --no-revs --no-flags "$@")" || exit $?
+
+#echo "dirs is {$dirs}"
+eval $(echo set -- $dirs)
+if [ "$#" -ne 1 ]; then
+	die "Must provide exactly one subtree dir (got $#)"
+fi
+dir="$1"
+
+debug "command: {$command}"
+debug "quiet: {$quiet}"
+debug "revs: {$revs}"
+debug "dir: {$dir}"
+
+cache_setup()
+{
+	cachedir="$GIT_DIR/subtree-cache/$dir"
+	rm -rf "$cachedir" || die "Can't delete old cachedir: $cachedir"
+	mkdir -p "$cachedir" || die "Can't create new cachedir: $cachedir"
+	debug "Using cachedir: $cachedir" >&2
+	echo "$cachedir"
+}
+
+cache_get()
+{
+	for oldrev in $*; do
+		if [ -r "$cachedir/$oldrev" ]; then
+			read newrev <"$cachedir/$oldrev"
+			echo $newrev
+		fi
+	done
+}
+
+cache_set()
+{
+	oldrev="$1"
+	newrev="$2"
+	if [ -e "$cachedir/$oldrev" ]; then
+		die "cache for $oldrev already exists!"
+	fi
+	echo "$newrev" >"$cachedir/$oldrev"
+}
+
+cmd_split()
+{
+	debug "Splitting $dir..."
+	cache_setup || exit $?
+	
+	git rev-list --reverse --parents $revs -- "$dir" |
+	while read rev parents; do
+		newparents=$(cache_get $parents)
+		echo "rev: $rev / $newparents"
+		
+		git ls-tree $rev -- "$dir" |
+		while read mode type tree name; do
+			p=""
+			for parent in $newparents; do
+				p="$p -p $parent"
+			done
+			newrev=$(echo synthetic | git commit-tree $tree $p) \
+				|| die "Can't create new commit for $rev / $tree"
+			cache_set $rev $newrev
+		done
+	done
+	
+	exit 0
+}
+
+cmd_merge()
+{
+	die "merge command not implemented yet"
+}
+
+"cmd_$command"

shellopts.sh

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+export PATH=$PWD:$PATH