Merge pull request #503 from Gottox/xdelta

Generates binary diffs for repository indexes.

common/hooks/post-pkg/01-xdelta_repolist.sh

@@ -0,0 +1,29 @@
+# This hook generates vcdiffs
+
+hook() {
+	set -x
+	type -P xdelta3 > /dev/null || return 0;
+
+	find $XBPS_REPOSITORY -name '*.genVcdiff' | xargs -r sha256sum | \
+		while read chk oldfile; do
+			newfile=${oldfile/.genVcdiff/}
+
+			if ! cmp -s "${newfile}" "${oldfile}"; then
+				newdiff="${newfile}.${chk}.vcdiff"
+				xdelta3 -f -e -s "${oldfile}" "${newfile}" "${newdiff}"
+				for diff in ${newfile}.*.vcdiff; do
+					[ "${diff}" = "${newdiff}" ] && continue;
+					cp -- "${diff}" "${diff}.tmp"
+					xdelta3 -f merge -m "${diff}.tmp" "${newdiff}" "${diff}"
+					rm -- "${diff}.tmp"
+				done
+			fi
+
+			# generate an empty diff to the new file
+			newchk=`sha256sum ${newfile} | awk '{ print $1 }'`
+			xdelta3 -f -e -s "${newfile}" "${newfile}" \
+				"${newfile}.${newchk}.vcdiff"
+
+			rm -- "${oldfile}"
+		done
+}

common/hooks/pre-pkg/01-xdelta_repolist.sh

@@ -0,0 +1,11 @@
+# this hook marks files which are about to change for generating vcdiffs
+
+hook() {
+	type -P xdelta3 > /dev/null || return 0;
+
+	# create links to preserve old versions of repodata
+	find $XBPS_REPOSITORY -name '*-repodata' | \
+		while read; do
+			ln "${REPLY}" "${REPLY}.genVcdiff"
+		done
+}