3 files changed, 30 insertions, 9 deletions

diff --git a/vendor/github.com/klauspost/compress/zstd/decoder.go b/vendor/github.com/klauspost/compress/zstd/decoder.go
index cdda0de58..62fd37324 100644
--- a/vendor/github.com/klauspost/compress/zstd/decoder.go
+++ b/vendor/github.com/klauspost/compress/zstd/decoder.go
@@ -85,6 +85,10 @@ func NewReader(r io.Reader, opts ...DOption) (*Decoder, error) {
 	d.current.output = make(chan decodeOutput, d.o.concurrent)
 	d.current.flushed = true
 
+	if r == nil {
+		d.current.err = ErrDecoderNilInput
+	}
+
 	// Transfer option dicts.
 	d.dicts = make(map[uint32]dict, len(d.o.dicts))
 	for _, dc := range d.o.dicts {
@@ -111,7 +115,7 @@ func NewReader(r io.Reader, opts ...DOption) (*Decoder, error) {
 // When the stream is done, io.EOF will be returned.
 func (d *Decoder) Read(p []byte) (int, error) {
 	if d.stream == nil {
-		return 0, errors.New("no input has been initialized")
+		return 0, ErrDecoderNilInput
 	}
 	var n int
 	for {
@@ -152,12 +156,20 @@ func (d *Decoder) Read(p []byte) (int, error) {
 
 // Reset will reset the decoder the supplied stream after the current has finished processing.
 // Note that this functionality cannot be used after Close has been called.
+// Reset can be called with a nil reader to release references to the previous reader.
+// After being called with a nil reader, no other operations than Reset or DecodeAll or Close
+// should be used.
 func (d *Decoder) Reset(r io.Reader) error {
 	if d.current.err == ErrDecoderClosed {
 		return d.current.err
 	}
+
+	d.drainOutput()
+
 	if r == nil {
-		return errors.New("nil Reader sent as input")
+		d.current.err = ErrDecoderNilInput
+		d.current.flushed = true
+		return nil
 	}
 
 	if d.stream == nil {
@@ -166,8 +178,6 @@ func (d *Decoder) Reset(r io.Reader) error {
 		go d.startStreamDecoder(d.stream)
 	}
 
-	d.drainOutput()
-
 	// If bytes buffer and < 1MB, do sync decoding anyway.
 	if bb, ok := r.(*bytes.Buffer); ok && bb.Len() < 1<<20 {
 		if debug {
@@ -249,7 +259,7 @@ func (d *Decoder) drainOutput() {
 // Any error encountered during the write is also returned.
 func (d *Decoder) WriteTo(w io.Writer) (int64, error) {
 	if d.stream == nil {
-		return 0, errors.New("no input has been initialized")
+		return 0, ErrDecoderNilInput
 	}
 	var n int64
 	for {
diff --git a/vendor/github.com/klauspost/compress/zstd/seqdec.go b/vendor/github.com/klauspost/compress/zstd/seqdec.go
index b5c8ef133..1dd39e63b 100644
--- a/vendor/github.com/klauspost/compress/zstd/seqdec.go
+++ b/vendor/github.com/klauspost/compress/zstd/seqdec.go
@@ -181,11 +181,18 @@ func (s *sequenceDecs) decode(seqs int, br *bitReader, hist []byte) error {
 			return fmt.Errorf("output (%d) bigger than max block size", size)
 		}
 		if size > cap(s.out) {
-			// Not enough size, will be extremely rarely triggered,
+			// Not enough size, which can happen under high volume block streaming conditions
 			// but could be if destination slice is too small for sync operations.
-			// We add maxBlockSize to the capacity.
-			s.out = append(s.out, make([]byte, maxBlockSize)...)
-			s.out = s.out[:len(s.out)-maxBlockSize]
+			// over-allocating here can create a large amount of GC pressure so we try to keep
+			// it as contained as possible
+			used := len(s.out) - startSize
+			addBytes := 256 + ll + ml + used>>2
+			// Clamp to max block size.
+			if used+addBytes > maxBlockSize {
+				addBytes = maxBlockSize - used
+			}
+			s.out = append(s.out, make([]byte, addBytes)...)
+			s.out = s.out[:len(s.out)-addBytes]
 		}
 		if ml > maxMatchLen {
 			return fmt.Errorf("match len (%d) bigger than max allowed length", ml)
diff --git a/vendor/github.com/klauspost/compress/zstd/zstd.go b/vendor/github.com/klauspost/compress/zstd/zstd.go
index 0807719c8..0c761dd62 100644
--- a/vendor/github.com/klauspost/compress/zstd/zstd.go
+++ b/vendor/github.com/klauspost/compress/zstd/zstd.go
@@ -73,6 +73,10 @@ var (
 	// ErrDecoderClosed will be returned if the Decoder was used after
 	// Close has been called.
 	ErrDecoderClosed = errors.New("decoder used after Close")
+
+	// ErrDecoderNilInput is returned when a nil Reader was provided
+	// and an operation other than Reset/DecodeAll/Close was attempted.
+	ErrDecoderNilInput = errors.New("nil input provided as reader")
 )
 
 func println(a ...interface{}) {