[#3] signature: Add buffer pool

Signed-off-by: Dmitrii Stepanov <d.stepanov@yadro.com>

util/signature/buffer.go

@@ -0,0 +1,29 @@
+package signature
+
+import "sync"
+
+const poolSliceMaxSize = 64 * 1024
+
+var buffersPool = sync.Pool{
+	New: func() any {
+		return make([]byte, 0)
+	},
+}
+
+func newBufferFromPool(size int) []byte {
+	result := buffersPool.Get().([]byte)
+	if cap(result) < size {
+		result = make([]byte, size)
+	} else {
+		result = result[:size]
+	}
+	return result
+}
+
+func returnBufferToPool(buf []byte) {
+	if cap(buf) > poolSliceMaxSize {
+		return
+	}
+	buf = buf[:0]
+	buffersPool.Put(buf)
+}

util/signature/data.go

@@ -35,7 +35,10 @@ func SignDataWithHandler(key *ecdsa.PrivateKey, src DataSource, handler KeySigna
 		opts[i](cfg)
 	}
 
-	data, err := readSignedData(cfg, src)
+	buffer := newBufferFromPool(src.SignedDataSize())
+	defer returnBufferToPool(buffer)
+
+	data, err := src.ReadSignedData(buffer)
 	if err != nil {
 		return err
 	}
@@ -61,7 +64,10 @@ func VerifyDataWithSource(dataSrc DataSource, sigSrc KeySignatureSource, opts ..
 		opts[i](cfg)
 	}
 
-	data, err := readSignedData(cfg, dataSrc)
+	buffer := newBufferFromPool(dataSrc.SignedDataSize())
+	defer returnBufferToPool(buffer)
+
+	data, err := dataSrc.ReadSignedData(buffer)
 	if err != nil {
 		return err
 	}
@@ -76,13 +82,3 @@ func SignData(key *ecdsa.PrivateKey, v DataWithSignature, opts ...SignOption) er
 func VerifyData(src DataWithSignature, opts ...SignOption) error {
 	return VerifyDataWithSource(src, src.GetSignature, opts...)
 }
-
-func readSignedData(cfg *cfg, src DataSource) ([]byte, error) {
-	size := src.SignedDataSize()
-	if cfg.buffer == nil || cap(cfg.buffer) < size {
-		cfg.buffer = make([]byte, size)
-	} else {
-		cfg.buffer = cfg.buffer[:size]
-	}
-	return src.ReadSignedData(cfg.buffer)
-}

util/signature/options.go

@@ -13,7 +13,6 @@ import (
 type cfg struct {
 	schemeFixed bool
 	scheme      refs.SignatureScheme
-	buffer      []byte
 }
 
 func defaultCfg() *cfg {
@@ -36,9 +35,10 @@ func verify(cfg *cfg, data []byte, sig *refs.Signature) error {
 	case refs.ECDSA_RFC6979_SHA256:
 		return crypto.VerifyRFC6979(pub, data, sig.GetSign())
 	case refs.ECDSA_RFC6979_SHA256_WALLET_CONNECT:
-		buf := make([]byte, base64.StdEncoding.EncodedLen(len(data)))
-		base64.StdEncoding.Encode(buf, data)
-		if !walletconnect.Verify(pub, buf, sig.GetSign()) {
+		buffer := newBufferFromPool(base64.StdEncoding.EncodedLen(len(data)))
+		defer returnBufferToPool(buffer)
+		base64.StdEncoding.Encode(buffer, data)
+		if !walletconnect.Verify(pub, buffer, sig.GetSign()) {
 			return crypto.ErrInvalidSignature
 		}
 		return nil
@@ -54,9 +54,10 @@ func sign(cfg *cfg, key *ecdsa.PrivateKey, data []byte) ([]byte, error) {
 	case refs.ECDSA_RFC6979_SHA256:
 		return crypto.SignRFC6979(key, data)
 	case refs.ECDSA_RFC6979_SHA256_WALLET_CONNECT:
-		buf := make([]byte, base64.StdEncoding.EncodedLen(len(data)))
-		base64.StdEncoding.Encode(buf, data)
-		return walletconnect.Sign(key, buf)
+		buffer := newBufferFromPool(base64.StdEncoding.EncodedLen(len(data)))
+		defer returnBufferToPool(buffer)
+		base64.StdEncoding.Encode(buffer, data)
+		return walletconnect.Sign(key, buffer)
 	default:
 		panic(fmt.Sprintf("unsupported scheme %s", cfg.scheme))
 	}
@@ -69,13 +70,6 @@ func SignWithRFC6979() SignOption {
 	}
 }
 
-// WithBuffer allows providing pre-allocated buffer for signature verification.
-func WithBuffer(buf []byte) SignOption {
-	return func(c *cfg) {
-		c.buffer = buf
-	}
-}
-
 func SignWithWalletConnect() SignOption {
 	return func(c *cfg) {
 		c.scheme = refs.ECDSA_RFC6979_SHA256_WALLET_CONNECT