Add antireplay cache

antireplay/noop.go

@@ -0,0 +1,11 @@
+package antireplay
+
+import "github.com/9seconds/mtg/v2/mtglib"
+
+type noop struct{}
+
+func (n noop) SeenBefore(_ []byte) bool { return false }
+
+func NewNoop() mtglib.AntiReplayCache {
+	return noop{}
+}

antireplay/noop_test.go

@@ -0,0 +1,26 @@
+package antireplay_test
+
+import (
+	"testing"
+
+	"github.com/9seconds/mtg/v2/antireplay"
+	"github.com/stretchr/testify/suite"
+)
+
+type NoopTestSuite struct {
+	suite.Suite
+}
+
+func (suite *NoopTestSuite) TestOp() {
+	filter := antireplay.NewNoop()
+
+	suite.False(filter.SeenBefore([]byte{1, 2, 3}))
+	suite.False(filter.SeenBefore([]byte{4, 5, 6}))
+	suite.False(filter.SeenBefore([]byte{1, 2, 3}))
+	suite.False(filter.SeenBefore([]byte{4, 5, 6}))
+}
+
+func TestNoop(t *testing.T) {
+	t.Parallel()
+	suite.Run(t, &NoopTestSuite{})
+}

antireplay/stable_bloom_filter.go

@@ -0,0 +1,24 @@
+package antireplay
+
+import (
+	"github.com/9seconds/mtg/v2/mtglib"
+	"github.com/OneOfOne/xxhash"
+	boom "github.com/tylertreat/BoomFilters"
+)
+
+type stableBloomFilter struct {
+	filter boom.StableBloomFilter
+}
+
+func (s *stableBloomFilter) SeenBefore(digest []byte) bool {
+	return s.filter.TestAndAdd(digest)
+}
+
+func NewStableBloomFilter(byteSize uint, errorRate float64) mtglib.AntiReplayCache {
+	sf := boom.NewDefaultStableBloomFilter(byteSize*8, errorRate) // nolint: gomnd
+    sf.SetHash(xxhash.New64())
+
+	return &stableBloomFilter{
+		filter: *sf,
+	}
+}

antireplay/stable_bloom_filter_test.go

@@ -0,0 +1,26 @@
+package antireplay_test
+
+import (
+	"testing"
+
+	"github.com/9seconds/mtg/v2/antireplay"
+	"github.com/stretchr/testify/suite"
+)
+
+type StableBloomFilterTestSuite struct {
+	suite.Suite
+}
+
+func (suite *StableBloomFilterTestSuite) TestOp() {
+	filter := antireplay.NewStableBloomFilter(500, 0.001)
+
+	suite.False(filter.SeenBefore([]byte{1, 2, 3}))
+	suite.False(filter.SeenBefore([]byte{4, 5, 6}))
+	suite.True(filter.SeenBefore([]byte{1, 2, 3}))
+	suite.True(filter.SeenBefore([]byte{4, 5, 6}))
+}
+
+func TestStableBloomFilter(t *testing.T) {
+	t.Parallel()
+	suite.Run(t, &StableBloomFilterTestSuite{})
+}