Bump github.com/mattermost/mattermost-server/v6 from 6.1.0 to 6.3.0 (#1686)

Bumps [github.com/mattermost/mattermost-server/v6](https://github.com/mattermost/mattermost-server) from 6.1.0 to 6.3.0.
- [Release notes](https://github.com/mattermost/mattermost-server/releases)
- [Changelog](https://github.com/mattermost/mattermost-server/blob/master/CHANGELOG.md)
- [Commits](https://github.com/mattermost/mattermost-server/compare/v6.1.0...v6.3.0)

---
updated-dependencies:
- dependency-name: github.com/mattermost/mattermost-server/v6
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

1 files changed, 565 insertions, 0 deletions

diff --git a/vendor/github.com/klauspost/compress/s2/decode.go b/vendor/github.com/klauspost/compress/s2/decode.go
new file mode 100644
index 00000000..d0ae5304
--- /dev/null
+++ b/vendor/github.com/klauspost/compress/s2/decode.go
@@ -0,0 +1,565 @@
+// Copyright 2011 The Snappy-Go Authors. All rights reserved.
+// Copyright (c) 2019 Klaus Post. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package s2
+
+import (
+	"encoding/binary"
+	"errors"
+	"io"
+)
+
+var (
+	// ErrCorrupt reports that the input is invalid.
+	ErrCorrupt = errors.New("s2: corrupt input")
+	// ErrCRC reports that the input failed CRC validation (streams only)
+	ErrCRC = errors.New("s2: corrupt input, crc mismatch")
+	// ErrTooLarge reports that the uncompressed length is too large.
+	ErrTooLarge = errors.New("s2: decoded block is too large")
+	// ErrUnsupported reports that the input isn't supported.
+	ErrUnsupported = errors.New("s2: unsupported input")
+)
+
+// DecodedLen returns the length of the decoded block.
+func DecodedLen(src []byte) (int, error) {
+	v, _, err := decodedLen(src)
+	return v, err
+}
+
+// decodedLen returns the length of the decoded block and the number of bytes
+// that the length header occupied.
+func decodedLen(src []byte) (blockLen, headerLen int, err error) {
+	v, n := binary.Uvarint(src)
+	if n <= 0 || v > 0xffffffff {
+		return 0, 0, ErrCorrupt
+	}
+
+	const wordSize = 32 << (^uint(0) >> 32 & 1)
+	if wordSize == 32 && v > 0x7fffffff {
+		return 0, 0, ErrTooLarge
+	}
+	return int(v), n, nil
+}
+
+const (
+	decodeErrCodeCorrupt = 1
+)
+
+// Decode returns the decoded form of src. The returned slice may be a sub-
+// slice of dst if dst was large enough to hold the entire decoded block.
+// Otherwise, a newly allocated slice will be returned.
+//
+// The dst and src must not overlap. It is valid to pass a nil dst.
+func Decode(dst, src []byte) ([]byte, error) {
+	dLen, s, err := decodedLen(src)
+	if err != nil {
+		return nil, err
+	}
+	if dLen <= cap(dst) {
+		dst = dst[:dLen]
+	} else {
+		dst = make([]byte, dLen)
+	}
+	if s2Decode(dst, src[s:]) != 0 {
+		return nil, ErrCorrupt
+	}
+	return dst, nil
+}
+
+// NewReader returns a new Reader that decompresses from r, using the framing
+// format described at
+// https://github.com/google/snappy/blob/master/framing_format.txt with S2 changes.
+func NewReader(r io.Reader, opts ...ReaderOption) *Reader {
+	nr := Reader{
+		r:        r,
+		maxBlock: maxBlockSize,
+	}
+	for _, opt := range opts {
+		if err := opt(&nr); err != nil {
+			nr.err = err
+			return &nr
+		}
+	}
+	nr.maxBufSize = MaxEncodedLen(nr.maxBlock) + checksumSize
+	if nr.lazyBuf > 0 {
+		nr.buf = make([]byte, MaxEncodedLen(nr.lazyBuf)+checksumSize)
+	} else {
+		nr.buf = make([]byte, MaxEncodedLen(defaultBlockSize)+checksumSize)
+	}
+	nr.paramsOK = true
+	return &nr
+}
+
+// ReaderOption is an option for creating a decoder.
+type ReaderOption func(*Reader) error
+
+// ReaderMaxBlockSize allows to control allocations if the stream
+// has been compressed with a smaller WriterBlockSize, or with the default 1MB.
+// Blocks must be this size or smaller to decompress,
+// otherwise the decoder will return ErrUnsupported.
+//
+// For streams compressed with Snappy this can safely be set to 64KB (64 << 10).
+//
+// Default is the maximum limit of 4MB.
+func ReaderMaxBlockSize(blockSize int) ReaderOption {
+	return func(r *Reader) error {
+		if blockSize > maxBlockSize || blockSize <= 0 {
+			return errors.New("s2: block size too large. Must be <= 4MB and > 0")
+		}
+		if r.lazyBuf == 0 && blockSize < defaultBlockSize {
+			r.lazyBuf = blockSize
+		}
+		r.maxBlock = blockSize
+		return nil
+	}
+}
+
+// ReaderAllocBlock allows to control upfront stream allocations
+// and not allocate for frames bigger than this initially.
+// If frames bigger than this is seen a bigger buffer will be allocated.
+//
+// Default is 1MB, which is default output size.
+func ReaderAllocBlock(blockSize int) ReaderOption {
+	return func(r *Reader) error {
+		if blockSize > maxBlockSize || blockSize < 1024 {
+			return errors.New("s2: invalid ReaderAllocBlock. Must be <= 4MB and >= 1024")
+		}
+		r.lazyBuf = blockSize
+		return nil
+	}
+}
+
+// Reader is an io.Reader that can read Snappy-compressed bytes.
+type Reader struct {
+	r       io.Reader
+	err     error
+	decoded []byte
+	buf     []byte
+	// decoded[i:j] contains decoded bytes that have not yet been passed on.
+	i, j int
+	// maximum block size allowed.
+	maxBlock int
+	// maximum expected buffer size.
+	maxBufSize int
+	// alloc a buffer this size if > 0.
+	lazyBuf     int
+	readHeader  bool
+	paramsOK    bool
+	snappyFrame bool
+}
+
+// ensureBufferSize will ensure that the buffer can take at least n bytes.
+// If false is returned the buffer exceeds maximum allowed size.
+func (r *Reader) ensureBufferSize(n int) bool {
+	if len(r.buf) >= n {
+		return true
+	}
+	if n > r.maxBufSize {
+		r.err = ErrCorrupt
+		return false
+	}
+	// Realloc buffer.
+	r.buf = make([]byte, n)
+	return true
+}
+
+// Reset discards any buffered data, resets all state, and switches the Snappy
+// reader to read from r. This permits reusing a Reader rather than allocating
+// a new one.
+func (r *Reader) Reset(reader io.Reader) {
+	if !r.paramsOK {
+		return
+	}
+	r.r = reader
+	r.err = nil
+	r.i = 0
+	r.j = 0
+	r.readHeader = false
+}
+
+func (r *Reader) readFull(p []byte, allowEOF bool) (ok bool) {
+	if _, r.err = io.ReadFull(r.r, p); r.err != nil {
+		if r.err == io.ErrUnexpectedEOF || (r.err == io.EOF && !allowEOF) {
+			r.err = ErrCorrupt
+		}
+		return false
+	}
+	return true
+}
+
+// skipN will skip n bytes.
+// If the supplied reader supports seeking that is used.
+// tmp is used as a temporary buffer for reading.
+// The supplied slice does not need to be the size of the read.
+func (r *Reader) skipN(tmp []byte, n int, allowEOF bool) (ok bool) {
+	if rs, ok := r.r.(io.ReadSeeker); ok {
+		_, err := rs.Seek(int64(n), io.SeekCurrent)
+		if err == nil {
+			return true
+		}
+		if err == io.ErrUnexpectedEOF || (r.err == io.EOF && !allowEOF) {
+			r.err = ErrCorrupt
+			return false
+		}
+	}
+	for n > 0 {
+		if n < len(tmp) {
+			tmp = tmp[:n]
+		}
+		if _, r.err = io.ReadFull(r.r, tmp); r.err != nil {
+			if r.err == io.ErrUnexpectedEOF || (r.err == io.EOF && !allowEOF) {
+				r.err = ErrCorrupt
+			}
+			return false
+		}
+		n -= len(tmp)
+	}
+	return true
+}
+
+// Read satisfies the io.Reader interface.
+func (r *Reader) Read(p []byte) (int, error) {
+	if r.err != nil {
+		return 0, r.err
+	}
+	for {
+		if r.i < r.j {
+			n := copy(p, r.decoded[r.i:r.j])
+			r.i += n
+			return n, nil
+		}
+		if !r.readFull(r.buf[:4], true) {
+			return 0, r.err
+		}
+		chunkType := r.buf[0]
+		if !r.readHeader {
+			if chunkType != chunkTypeStreamIdentifier {
+				r.err = ErrCorrupt
+				return 0, r.err
+			}
+			r.readHeader = true
+		}
+		chunkLen := int(r.buf[1]) | int(r.buf[2])<<8 | int(r.buf[3])<<16
+
+		// The chunk types are specified at
+		// https://github.com/google/snappy/blob/master/framing_format.txt
+		switch chunkType {
+		case chunkTypeCompressedData:
+			// Section 4.2. Compressed data (chunk type 0x00).
+			if chunkLen < checksumSize {
+				r.err = ErrCorrupt
+				return 0, r.err
+			}
+			if !r.ensureBufferSize(chunkLen) {
+				if r.err == nil {
+					r.err = ErrUnsupported
+				}
+				return 0, r.err
+			}
+			buf := r.buf[:chunkLen]
+			if !r.readFull(buf, false) {
+				return 0, r.err
+			}
+			checksum := uint32(buf[0]) | uint32(buf[1])<<8 | uint32(buf[2])<<16 | uint32(buf[3])<<24
+			buf = buf[checksumSize:]
+
+			n, err := DecodedLen(buf)
+			if err != nil {
+				r.err = err
+				return 0, r.err
+			}
+			if r.snappyFrame && n > maxSnappyBlockSize {
+				r.err = ErrCorrupt
+				return 0, r.err
+			}
+
+			if n > len(r.decoded) {
+				if n > r.maxBlock {
+					r.err = ErrCorrupt
+					return 0, r.err
+				}
+				r.decoded = make([]byte, n)
+			}
+			if _, err := Decode(r.decoded, buf); err != nil {
+				r.err = err
+				return 0, r.err
+			}
+			if crc(r.decoded[:n]) != checksum {
+				r.err = ErrCRC
+				return 0, r.err
+			}
+			r.i, r.j = 0, n
+			continue
+
+		case chunkTypeUncompressedData:
+			// Section 4.3. Uncompressed data (chunk type 0x01).
+			if chunkLen < checksumSize {
+				r.err = ErrCorrupt
+				return 0, r.err
+			}
+			if !r.ensureBufferSize(chunkLen) {
+				if r.err == nil {
+					r.err = ErrUnsupported
+				}
+				return 0, r.err
+			}
+			buf := r.buf[:checksumSize]
+			if !r.readFull(buf, false) {
+				return 0, r.err
+			}
+			checksum := uint32(buf[0]) | uint32(buf[1])<<8 | uint32(buf[2])<<16 | uint32(buf[3])<<24
+			// Read directly into r.decoded instead of via r.buf.
+			n := chunkLen - checksumSize
+			if r.snappyFrame && n > maxSnappyBlockSize {
+				r.err = ErrCorrupt
+				return 0, r.err
+			}
+			if n > len(r.decoded) {
+				if n > r.maxBlock {
+					r.err = ErrCorrupt
+					return 0, r.err
+				}
+				r.decoded = make([]byte, n)
+			}
+			if !r.readFull(r.decoded[:n], false) {
+				return 0, r.err
+			}
+			if crc(r.decoded[:n]) != checksum {
+				r.err = ErrCRC
+				return 0, r.err
+			}
+			r.i, r.j = 0, n
+			continue
+
+		case chunkTypeStreamIdentifier:
+			// Section 4.1. Stream identifier (chunk type 0xff).
+			if chunkLen != len(magicBody) {
+				r.err = ErrCorrupt
+				return 0, r.err
+			}
+			if !r.readFull(r.buf[:len(magicBody)], false) {
+				return 0, r.err
+			}
+			if string(r.buf[:len(magicBody)]) != magicBody {
+				if string(r.buf[:len(magicBody)]) != magicBodySnappy {
+					r.err = ErrCorrupt
+					return 0, r.err
+				} else {
+					r.snappyFrame = true
+				}
+			} else {
+				r.snappyFrame = false
+			}
+			continue
+		}
+
+		if chunkType <= 0x7f {
+			// Section 4.5. Reserved unskippable chunks (chunk types 0x02-0x7f).
+			r.err = ErrUnsupported
+			return 0, r.err
+		}
+		// Section 4.4 Padding (chunk type 0xfe).
+		// Section 4.6. Reserved skippable chunks (chunk types 0x80-0xfd).
+		if chunkLen > maxBlockSize {
+			r.err = ErrUnsupported
+			return 0, r.err
+		}
+
+		if !r.skipN(r.buf, chunkLen, false) {
+			return 0, r.err
+		}
+	}
+}
+
+// Skip will skip n bytes forward in the decompressed output.
+// For larger skips this consumes less CPU and is faster than reading output and discarding it.
+// CRC is not checked on skipped blocks.
+// io.ErrUnexpectedEOF is returned if the stream ends before all bytes have been skipped.
+// If a decoding error is encountered subsequent calls to Read will also fail.
+func (r *Reader) Skip(n int64) error {
+	if n < 0 {
+		return errors.New("attempted negative skip")
+	}
+	if r.err != nil {
+		return r.err
+	}
+
+	for n > 0 {
+		if r.i < r.j {
+			// Skip in buffer.
+			// decoded[i:j] contains decoded bytes that have not yet been passed on.
+			left := int64(r.j - r.i)
+			if left >= n {
+				r.i += int(n)
+				return nil
+			}
+			n -= int64(r.j - r.i)
+			r.i, r.j = 0, 0
+		}
+
+		// Buffer empty; read blocks until we have content.
+		if !r.readFull(r.buf[:4], true) {
+			if r.err == io.EOF {
+				r.err = io.ErrUnexpectedEOF
+			}
+			return r.err
+		}
+		chunkType := r.buf[0]
+		if !r.readHeader {
+			if chunkType != chunkTypeStreamIdentifier {
+				r.err = ErrCorrupt
+				return r.err
+			}
+			r.readHeader = true
+		}
+		chunkLen := int(r.buf[1]) | int(r.buf[2])<<8 | int(r.buf[3])<<16
+
+		// The chunk types are specified at
+		// https://github.com/google/snappy/blob/master/framing_format.txt
+		switch chunkType {
+		case chunkTypeCompressedData:
+			// Section 4.2. Compressed data (chunk type 0x00).
+			if chunkLen < checksumSize {
+				r.err = ErrCorrupt
+				return r.err
+			}
+			if !r.ensureBufferSize(chunkLen) {
+				if r.err == nil {
+					r.err = ErrUnsupported
+				}
+				return r.err
+			}
+			buf := r.buf[:chunkLen]
+			if !r.readFull(buf, false) {
+				return r.err
+			}
+			checksum := uint32(buf[0]) | uint32(buf[1])<<8 | uint32(buf[2])<<16 | uint32(buf[3])<<24
+			buf = buf[checksumSize:]
+
+			dLen, err := DecodedLen(buf)
+			if err != nil {
+				r.err = err
+				return r.err
+			}
+			if dLen > r.maxBlock {
+				r.err = ErrCorrupt
+				return r.err
+			}
+			// Check if destination is within this block
+			if int64(dLen) > n {
+				if len(r.decoded) < dLen {
+					r.decoded = make([]byte, dLen)
+				}
+				if _, err := Decode(r.decoded, buf); err != nil {
+					r.err = err
+					return r.err
+				}
+				if crc(r.decoded[:dLen]) != checksum {
+					r.err = ErrCorrupt
+					return r.err
+				}
+			} else {
+				// Skip block completely
+				n -= int64(dLen)
+				dLen = 0
+			}
+			r.i, r.j = 0, dLen
+			continue
+		case chunkTypeUncompressedData:
+			// Section 4.3. Uncompressed data (chunk type 0x01).
+			if chunkLen < checksumSize {
+				r.err = ErrCorrupt
+				return r.err
+			}
+			if !r.ensureBufferSize(chunkLen) {
+				if r.err != nil {
+					r.err = ErrUnsupported
+				}
+				return r.err
+			}
+			buf := r.buf[:checksumSize]
+			if !r.readFull(buf, false) {
+				return r.err
+			}
+			checksum := uint32(buf[0]) | uint32(buf[1])<<8 | uint32(buf[2])<<16 | uint32(buf[3])<<24
+			// Read directly into r.decoded instead of via r.buf.
+			n2 := chunkLen - checksumSize
+			if n2 > len(r.decoded) {
+				if n2 > r.maxBlock {
+					r.err = ErrCorrupt
+					return r.err
+				}
+				r.decoded = make([]byte, n2)
+			}
+			if !r.readFull(r.decoded[:n2], false) {
+				return r.err
+			}
+			if int64(n2) < n {
+				if crc(r.decoded[:n2]) != checksum {
+					r.err = ErrCorrupt
+					return r.err
+				}
+			}
+			r.i, r.j = 0, n2
+			continue
+		case chunkTypeStreamIdentifier:
+			// Section 4.1. Stream identifier (chunk type 0xff).
+			if chunkLen != len(magicBody) {
+				r.err = ErrCorrupt
+				return r.err
+			}
+			if !r.readFull(r.buf[:len(magicBody)], false) {
+				return r.err
+			}
+			if string(r.buf[:len(magicBody)]) != magicBody {
+				if string(r.buf[:len(magicBody)]) != magicBodySnappy {
+					r.err = ErrCorrupt
+					return r.err
+				}
+			}
+
+			continue
+		}
+
+		if chunkType <= 0x7f {
+			// Section 4.5. Reserved unskippable chunks (chunk types 0x02-0x7f).
+			r.err = ErrUnsupported
+			return r.err
+		}
+		if chunkLen > maxBlockSize {
+			r.err = ErrUnsupported
+			return r.err
+		}
+		// Section 4.4 Padding (chunk type 0xfe).
+		// Section 4.6. Reserved skippable chunks (chunk types 0x80-0xfd).
+		if !r.skipN(r.buf, chunkLen, false) {
+			return r.err
+		}
+	}
+	return nil
+}
+
+// ReadByte satisfies the io.ByteReader interface.
+func (r *Reader) ReadByte() (byte, error) {
+	if r.err != nil {
+		return 0, r.err
+	}
+	if r.i < r.j {
+		c := r.decoded[r.i]
+		r.i++
+		return c, nil
+	}
+	var tmp [1]byte
+	for i := 0; i < 10; i++ {
+		n, err := r.Read(tmp[:])
+		if err != nil {
+			return 0, err
+		}
+		if n == 1 {
+			return tmp[0], nil
+		}
+	}
+	return 0, io.ErrNoProgress
+}