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Work on adding overall checksum support

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This commit is contained in:
Kovid Goyal
2023-07-08 10:41:56 +05:30
parent d676886ab8
commit e125f803b3
2 changed files with 74 additions and 10 deletions
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39
tools/rsync/api.go
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@@ -1,15 +1,26 @@
// License: GPLv3 Copyright: 2023, Kovid Goyal, <kovid at kovidgoyal.net>
// First create a patcher with:
// p = NewPatcher()
// Create a signature for the file you want to update using
// p.CreateSignatureIterator(file_to_update)
// Now create a Differ with the created signature
// d = NewDiffer()
// d.AddSignatureData(signature_data_from_previous_step)
// Now create a delta based on the signature and the reference file
// d.CreateDelta(reference_file)
// Finally, apply this delta using the patcher to produce a file identical to reference_file
// based ont he delta data and file_to_update
// p.StartDelta(output_file, file_to_update)
// p.UpdateDelta(...)
// p.FinishDelta()
package rsync
import (
"fmt"
"hash"
"io"
"math"
"github.com/zeebo/xxh3"
"kitty/tools/utils"
)
@@ -19,10 +30,14 @@ const MaxBlockSize int = 1024 * 1024 // sqrt of 1TB
type StrongHashType uint16
type WeakHashType uint16
type ChecksumType uint16
const (
XXH3 StrongHashType = iota
)
const (
XXH3128Sum ChecksumType = iota
)
const (
Rsync WeakHashType = iota
)
@@ -33,6 +48,7 @@ type Api struct {
rsync rsync
signature []BlockHash
Checksum_type ChecksumType
Strong_hash_type StrongHashType
Weak_hash_type WeakHashType
Grow_buffer_func GrowBufferFunction
@@ -57,13 +73,20 @@ func (self *Api) read_signature_header(data []byte) (consumed int, err error) {
if len(data) < 12 {
return -1, io.ErrShortBuffer
}
if version := bin.Uint32(data); version != 0 {
if version := bin.Uint16(data); version != 0 {
return consumed, fmt.Errorf("Invalid version in signature header: %d", version)
}
switch csum := ChecksumType(bin.Uint16(data[2:])); csum {
case XXH3128Sum:
self.Checksum_type = XXH3128Sum
self.rsync.SetChecksummer(new_xxh3_128)
default:
return consumed, fmt.Errorf("Invalid checksum_type in signature header: %d", csum)
}
switch strong_hash := StrongHashType(bin.Uint16(data[4:])); strong_hash {
case XXH3:
self.Strong_hash_type = strong_hash
self.rsync.SetHasher(func() hash.Hash64 { return xxh3.New() })
self.rsync.SetHasher(new_xxh3_64)
default:
return consumed, fmt.Errorf("Invalid strong_hash in signature header: %d", strong_hash)
}
@@ -206,7 +229,8 @@ func (self *Patcher) CreateSignatureIterator(src io.Reader) OutputIterator {
var b []byte
it = self.rsync.CreateSignatureIterator(src)
output, b = ensure_size(output, 12, gbf)
bin.PutUint32(b, 0)
bin.PutUint16(b, 0)
bin.PutUint16(b[2:], uint16(self.Checksum_type))
bin.PutUint16(b[4:], uint16(self.Strong_hash_type))
bin.PutUint16(b[6:], uint16(self.Weak_hash_type))
bin.PutUint32(b[8:], uint32(self.rsync.BlockSize))
@@ -288,7 +312,8 @@ func NewPatcher(expected_input_size int64) (ans *Patcher) {
}
ans = &Patcher{}
ans.rsync.BlockSize = utils.Min(bs, MaxBlockSize)
ans.rsync.SetHasher(func() hash.Hash64 { return xxh3.New() })
ans.rsync.SetHasher(new_xxh3_64)
ans.rsync.SetChecksummer(new_xxh3_128)
if ans.rsync.HashBlockSize() > 0 && ans.rsync.HashBlockSize() < ans.rsync.BlockSize {
ans.rsync.BlockSize = (ans.rsync.BlockSize / ans.rsync.HashBlockSize()) * ans.rsync.HashBlockSize()