Files
dolt/go/store/nbs/util.go

105 lines
2.3 KiB
Go

// Copyright 2021 Dolthub, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package nbs
import (
"context"
"io"
"math"
"github.com/dolthub/dolt/go/libraries/utils/iohelp"
"github.com/dolthub/dolt/go/store/chunks"
"github.com/dolthub/dolt/go/store/hash"
)
func IterChunks(ctx context.Context, rd io.ReadSeeker, cb func(chunk chunks.Chunk) (stop bool, err error)) error {
idx, err := readTableIndexByCopy(ctx, rd, &UnlimitedQuotaProvider{})
if err != nil {
return err
}
defer idx.Close()
seen := make(map[addr]bool)
for i := uint32(0); i < idx.chunkCount(); i++ {
var a addr
ie, err := idx.indexEntry(i, &a)
if err != nil {
return err
}
if _, ok := seen[a]; !ok {
seen[a] = true
chunkBytes, err := readNFrom(rd, ie.Offset(), ie.Length())
if err != nil {
return err
}
cmpChnk, err := NewCompressedChunk(hash.Hash(a), chunkBytes)
if err != nil {
return err
}
chunk, err := cmpChnk.ToChunk()
if err != nil {
return err
}
stop, err := cb(chunk)
if err != nil {
return err
} else if stop {
break
}
}
}
return nil
}
func GetTableIndexPrefixes(ctx context.Context, rd io.ReadSeeker) (prefixes []uint64, err error) {
idx, err := readTableIndexByCopy(ctx, rd, &UnlimitedQuotaProvider{})
if err != nil {
return nil, err
}
defer func() {
cerr := idx.Close()
if err == nil {
err = cerr
}
}()
prefixes, err = idx.prefixes()
if err != nil {
return nil, err
}
return
}
func GuessPrefixOrdinal(prefix uint64, n uint32) int {
hi := prefix >> 32
return int((hi * uint64(n)) / uint64(math.MaxUint32))
}
func readNFrom(rd io.ReadSeeker, offset uint64, length uint32) ([]byte, error) {
_, err := rd.Seek(int64(offset), io.SeekStart)
if err != nil {
return nil, err
}
return iohelp.ReadNBytes(rd, int(length))
}