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, 431 insertions, 0 deletions

diff --git a/vendor/github.com/klauspost/compress/s2/encode_better.go b/vendor/github.com/klauspost/compress/s2/encode_better.go
new file mode 100644
index 00000000..943215b8
--- /dev/null
+++ b/vendor/github.com/klauspost/compress/s2/encode_better.go
@@ -0,0 +1,431 @@
+// Copyright 2016 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 (
+	"math/bits"
+)
+
+// hash4 returns the hash of the lowest 4 bytes of u to fit in a hash table with h bits.
+// Preferably h should be a constant and should always be <32.
+func hash4(u uint64, h uint8) uint32 {
+	const prime4bytes = 2654435761
+	return (uint32(u) * prime4bytes) >> ((32 - h) & 31)
+}
+
+// hash5 returns the hash of the lowest 5 bytes of u to fit in a hash table with h bits.
+// Preferably h should be a constant and should always be <64.
+func hash5(u uint64, h uint8) uint32 {
+	const prime5bytes = 889523592379
+	return uint32(((u << (64 - 40)) * prime5bytes) >> ((64 - h) & 63))
+}
+
+// hash7 returns the hash of the lowest 7 bytes of u to fit in a hash table with h bits.
+// Preferably h should be a constant and should always be <64.
+func hash7(u uint64, h uint8) uint32 {
+	const prime7bytes = 58295818150454627
+	return uint32(((u << (64 - 56)) * prime7bytes) >> ((64 - h) & 63))
+}
+
+// hash8 returns the hash of u to fit in a hash table with h bits.
+// Preferably h should be a constant and should always be <64.
+func hash8(u uint64, h uint8) uint32 {
+	const prime8bytes = 0xcf1bbcdcb7a56463
+	return uint32((u * prime8bytes) >> ((64 - h) & 63))
+}
+
+// encodeBlockBetter encodes a non-empty src to a guaranteed-large-enough dst. It
+// assumes that the varint-encoded length of the decompressed bytes has already
+// been written.
+//
+// It also assumes that:
+//	len(dst) >= MaxEncodedLen(len(src)) &&
+// 	minNonLiteralBlockSize <= len(src) && len(src) <= maxBlockSize
+func encodeBlockBetterGo(dst, src []byte) (d int) {
+	// sLimit is when to stop looking for offset/length copies. The inputMargin
+	// lets us use a fast path for emitLiteral in the main loop, while we are
+	// looking for copies.
+	sLimit := len(src) - inputMargin
+	if len(src) < minNonLiteralBlockSize {
+		return 0
+	}
+
+	// Initialize the hash tables.
+	const (
+		// Long hash matches.
+		lTableBits    = 16
+		maxLTableSize = 1 << lTableBits
+
+		// Short hash matches.
+		sTableBits    = 14
+		maxSTableSize = 1 << sTableBits
+	)
+
+	var lTable [maxLTableSize]uint32
+	var sTable [maxSTableSize]uint32
+
+	// Bail if we can't compress to at least this.
+	dstLimit := len(src) - len(src)>>5 - 6
+
+	// nextEmit is where in src the next emitLiteral should start from.
+	nextEmit := 0
+
+	// The encoded form must start with a literal, as there are no previous
+	// bytes to copy, so we start looking for hash matches at s == 1.
+	s := 1
+	cv := load64(src, s)
+
+	// We initialize repeat to 0, so we never match on first attempt
+	repeat := 0
+
+	for {
+		candidateL := 0
+		nextS := 0
+		for {
+			// Next src position to check
+			nextS = s + (s-nextEmit)>>7 + 1
+			if nextS > sLimit {
+				goto emitRemainder
+			}
+			hashL := hash7(cv, lTableBits)
+			hashS := hash4(cv, sTableBits)
+			candidateL = int(lTable[hashL])
+			candidateS := int(sTable[hashS])
+			lTable[hashL] = uint32(s)
+			sTable[hashS] = uint32(s)
+
+			// Check repeat at offset checkRep.
+			const checkRep = 1
+			if false && uint32(cv>>(checkRep*8)) == load32(src, s-repeat+checkRep) {
+				base := s + checkRep
+				// Extend back
+				for i := base - repeat; base > nextEmit && i > 0 && src[i-1] == src[base-1]; {
+					i--
+					base--
+				}
+				d += emitLiteral(dst[d:], src[nextEmit:base])
+
+				// Extend forward
+				candidate := s - repeat + 4 + checkRep
+				s += 4 + checkRep
+				for s < len(src) {
+					if len(src)-s < 8 {
+						if src[s] == src[candidate] {
+							s++
+							candidate++
+							continue
+						}
+						break
+					}
+					if diff := load64(src, s) ^ load64(src, candidate); diff != 0 {
+						s += bits.TrailingZeros64(diff) >> 3
+						break
+					}
+					s += 8
+					candidate += 8
+				}
+				if nextEmit > 0 {
+					// same as `add := emitCopy(dst[d:], repeat, s-base)` but skips storing offset.
+					d += emitRepeat(dst[d:], repeat, s-base)
+				} else {
+					// First match, cannot be repeat.
+					d += emitCopy(dst[d:], repeat, s-base)
+				}
+				nextEmit = s
+				if s >= sLimit {
+					goto emitRemainder
+				}
+
+				cv = load64(src, s)
+				continue
+			}
+
+			if uint32(cv) == load32(src, candidateL) {
+				break
+			}
+
+			// Check our short candidate
+			if uint32(cv) == load32(src, candidateS) {
+				// Try a long candidate at s+1
+				hashL = hash7(cv>>8, lTableBits)
+				candidateL = int(lTable[hashL])
+				lTable[hashL] = uint32(s + 1)
+				if uint32(cv>>8) == load32(src, candidateL) {
+					s++
+					break
+				}
+				// Use our short candidate.
+				candidateL = candidateS
+				break
+			}
+
+			cv = load64(src, nextS)
+			s = nextS
+		}
+
+		// Extend backwards
+		for candidateL > 0 && s > nextEmit && src[candidateL-1] == src[s-1] {
+			candidateL--
+			s--
+		}
+
+		// Bail if we exceed the maximum size.
+		if d+(s-nextEmit) > dstLimit {
+			return 0
+		}
+
+		base := s
+		offset := base - candidateL
+
+		// Extend the 4-byte match as long as possible.
+		s += 4
+		candidateL += 4
+		for s < len(src) {
+			if len(src)-s < 8 {
+				if src[s] == src[candidateL] {
+					s++
+					candidateL++
+					continue
+				}
+				break
+			}
+			if diff := load64(src, s) ^ load64(src, candidateL); diff != 0 {
+				s += bits.TrailingZeros64(diff) >> 3
+				break
+			}
+			s += 8
+			candidateL += 8
+		}
+
+		if offset > 65535 && s-base <= 5 && repeat != offset {
+			// Bail if the match is equal or worse to the encoding.
+			s = nextS + 1
+			if s >= sLimit {
+				goto emitRemainder
+			}
+			cv = load64(src, s)
+			continue
+		}
+
+		d += emitLiteral(dst[d:], src[nextEmit:base])
+		if repeat == offset {
+			d += emitRepeat(dst[d:], offset, s-base)
+		} else {
+			d += emitCopy(dst[d:], offset, s-base)
+			repeat = offset
+		}
+
+		nextEmit = s
+		if s >= sLimit {
+			goto emitRemainder
+		}
+
+		if d > dstLimit {
+			// Do we have space for more, if not bail.
+			return 0
+		}
+		// Index match start+1 (long) and start+2 (short)
+		index0 := base + 1
+		// Index match end-2 (long) and end-1 (short)
+		index1 := s - 2
+
+		cv0 := load64(src, index0)
+		cv1 := load64(src, index1)
+		cv = load64(src, s)
+		lTable[hash7(cv0, lTableBits)] = uint32(index0)
+		lTable[hash7(cv0>>8, lTableBits)] = uint32(index0 + 1)
+		lTable[hash7(cv1, lTableBits)] = uint32(index1)
+		lTable[hash7(cv1>>8, lTableBits)] = uint32(index1 + 1)
+		sTable[hash4(cv0>>8, sTableBits)] = uint32(index0 + 1)
+		sTable[hash4(cv0>>16, sTableBits)] = uint32(index0 + 2)
+		sTable[hash4(cv1>>8, sTableBits)] = uint32(index1 + 1)
+	}
+
+emitRemainder:
+	if nextEmit < len(src) {
+		// Bail if we exceed the maximum size.
+		if d+len(src)-nextEmit > dstLimit {
+			return 0
+		}
+		d += emitLiteral(dst[d:], src[nextEmit:])
+	}
+	return d
+}
+
+// encodeBlockBetterSnappyGo encodes a non-empty src to a guaranteed-large-enough dst. It
+// assumes that the varint-encoded length of the decompressed bytes has already
+// been written.
+//
+// It also assumes that:
+//	len(dst) >= MaxEncodedLen(len(src)) &&
+// 	minNonLiteralBlockSize <= len(src) && len(src) <= maxBlockSize
+func encodeBlockBetterSnappyGo(dst, src []byte) (d int) {
+	// sLimit is when to stop looking for offset/length copies. The inputMargin
+	// lets us use a fast path for emitLiteral in the main loop, while we are
+	// looking for copies.
+	sLimit := len(src) - inputMargin
+	if len(src) < minNonLiteralBlockSize {
+		return 0
+	}
+
+	// Initialize the hash tables.
+	const (
+		// Long hash matches.
+		lTableBits    = 16
+		maxLTableSize = 1 << lTableBits
+
+		// Short hash matches.
+		sTableBits    = 14
+		maxSTableSize = 1 << sTableBits
+	)
+
+	var lTable [maxLTableSize]uint32
+	var sTable [maxSTableSize]uint32
+
+	// Bail if we can't compress to at least this.
+	dstLimit := len(src) - len(src)>>5 - 6
+
+	// nextEmit is where in src the next emitLiteral should start from.
+	nextEmit := 0
+
+	// The encoded form must start with a literal, as there are no previous
+	// bytes to copy, so we start looking for hash matches at s == 1.
+	s := 1
+	cv := load64(src, s)
+
+	// We initialize repeat to 0, so we never match on first attempt
+	repeat := 0
+	const maxSkip = 100
+
+	for {
+		candidateL := 0
+		nextS := 0
+		for {
+			// Next src position to check
+			nextS = (s-nextEmit)>>7 + 1
+			if nextS > maxSkip {
+				nextS = s + maxSkip
+			} else {
+				nextS += s
+			}
+
+			if nextS > sLimit {
+				goto emitRemainder
+			}
+			hashL := hash7(cv, lTableBits)
+			hashS := hash4(cv, sTableBits)
+			candidateL = int(lTable[hashL])
+			candidateS := int(sTable[hashS])
+			lTable[hashL] = uint32(s)
+			sTable[hashS] = uint32(s)
+
+			if uint32(cv) == load32(src, candidateL) {
+				break
+			}
+
+			// Check our short candidate
+			if uint32(cv) == load32(src, candidateS) {
+				// Try a long candidate at s+1
+				hashL = hash7(cv>>8, lTableBits)
+				candidateL = int(lTable[hashL])
+				lTable[hashL] = uint32(s + 1)
+				if uint32(cv>>8) == load32(src, candidateL) {
+					s++
+					break
+				}
+				// Use our short candidate.
+				candidateL = candidateS
+				break
+			}
+
+			cv = load64(src, nextS)
+			s = nextS
+		}
+
+		// Extend backwards
+		for candidateL > 0 && s > nextEmit && src[candidateL-1] == src[s-1] {
+			candidateL--
+			s--
+		}
+
+		// Bail if we exceed the maximum size.
+		if d+(s-nextEmit) > dstLimit {
+			return 0
+		}
+
+		base := s
+		offset := base - candidateL
+
+		// Extend the 4-byte match as long as possible.
+		s += 4
+		candidateL += 4
+		for s < len(src) {
+			if len(src)-s < 8 {
+				if src[s] == src[candidateL] {
+					s++
+					candidateL++
+					continue
+				}
+				break
+			}
+			if diff := load64(src, s) ^ load64(src, candidateL); diff != 0 {
+				s += bits.TrailingZeros64(diff) >> 3
+				break
+			}
+			s += 8
+			candidateL += 8
+		}
+
+		if offset > 65535 && s-base <= 5 && repeat != offset {
+			// Bail if the match is equal or worse to the encoding.
+			s = nextS + 1
+			if s >= sLimit {
+				goto emitRemainder
+			}
+			cv = load64(src, s)
+			continue
+		}
+
+		d += emitLiteral(dst[d:], src[nextEmit:base])
+		d += emitCopyNoRepeat(dst[d:], offset, s-base)
+		repeat = offset
+
+		nextEmit = s
+		if s >= sLimit {
+			goto emitRemainder
+		}
+
+		if d > dstLimit {
+			// Do we have space for more, if not bail.
+			return 0
+		}
+		// Index match start+1 (long) and start+2 (short)
+		index0 := base + 1
+		// Index match end-2 (long) and end-1 (short)
+		index1 := s - 2
+
+		cv0 := load64(src, index0)
+		cv1 := load64(src, index1)
+		cv = load64(src, s)
+		lTable[hash7(cv0, lTableBits)] = uint32(index0)
+		lTable[hash7(cv0>>8, lTableBits)] = uint32(index0 + 1)
+		lTable[hash7(cv1, lTableBits)] = uint32(index1)
+		lTable[hash7(cv1>>8, lTableBits)] = uint32(index1 + 1)
+		sTable[hash4(cv0>>8, sTableBits)] = uint32(index0 + 1)
+		sTable[hash4(cv0>>16, sTableBits)] = uint32(index0 + 2)
+		sTable[hash4(cv1>>8, sTableBits)] = uint32(index1 + 1)
+	}
+
+emitRemainder:
+	if nextEmit < len(src) {
+		// Bail if we exceed the maximum size.
+		if d+len(src)-nextEmit > dstLimit {
+			return 0
+		}
+		d += emitLiteral(dst[d:], src[nextEmit:])
+	}
+	return d
+}