1 files changed, 75 insertions, 0 deletions
diff --git a/merge.sh b/merge.sh
new file mode 100755
index 0000000..6f764de
--- /dev/null
+++ b/merge.sh
@@ -0,0 +1,75 @@
+#!/bin/bash -e
+if [ $# != 1 ]; then
+	echo >&2 "usage: $0 [outfile]"
+	exit 1
+fi
+
+OUT="$1"
+MERGE_INDEXES=$(realpath nutrimatic/bin/merge-indexes)
+MAKE_INDEX=$(realpath nutrimatic/bin/make-index)
+
+# merge-indexes FDs: stdin, stdout, stderr, [in...], out
+# fatal assumption: we'll never exceed MAX_ARG
+MAXMERGE=$(($(ulimit -n)-4))
+CUTOFF=1
+TMPDIR=$(mktemp -d mergetmp.XXXXX)
+MERGEDIR=$TMPDIR/merge
+INDEXDIR=$TMPDIR/index
+mkdir -p $MERGEDIR $INDEXDIR
+
+(
+	cd $MERGEDIR
+	m=0
+	while true; do
+		eof=0
+		if [ -e EOF ]; then
+			eof=1
+		fi
+		files=($(shopt -s nullglob; ls -S *.index *.merge | tail -n $MAXMERGE))
+		if [ $eof -eq 0 -a ${#files[@]} -lt 2 ]; then
+			sleep 1
+			continue
+		fi
+		out=shard.$(printf '%05d' $m).merge
+		m=$((m+1))
+		echo $out: ${files[@]}
+		$MERGE_INDEXES $CUTOFF ${files[@]} $out && rm ${files[@]}
+		if [ $eof -eq 1 -a ${#files[@]} -lt $MAXMERGE ]; then
+			mv $out ../merged
+			exit 0
+		fi
+	done
+) &
+merge_pid=$!
+
+(
+	n=0
+	while true; do
+		cur=$INDEXDIR/shard.$(printf '%05d' $n).index
+		n=$((n+1))
+		next=$INDEXDIR/shard.$(printf '%05d' $n).index
+		eof=$INDEXDIR/EOF
+		while [ ! -e "$next" -a ! -e "$eof" ]; do
+			sleep 1
+		done
+		echo "$cur"
+		mv "$cur" "$MERGEDIR/"
+		if [ ! -e "$next" -a -e "$eof" ]; then
+			mv "$eof" "$MERGEDIR/EOF"
+			exit 0
+		fi
+	done
+) &
+copy_pid=$!
+
+trap "rm -rf '$TMPDIR'; kill 0; exit" INT TERM
+
+# consumes stdin
+$MAKE_INDEX $INDEXDIR/shard
+touch $INDEXDIR/EOF
+
+wait $copy_pid
+wait $merge_pid
+mv $TMPDIR/merged "$OUT"
+rm -r $TMPDIR
+exit 0