78 lines
1.5 KiB
Go
78 lines
1.5 KiB
Go
package splitstore
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import (
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"crypto/rand"
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"golang.org/x/xerrors"
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bbloom "github.com/ipfs/bbloom"
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cid "github.com/ipfs/go-cid"
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blake2b "github.com/minio/blake2b-simd"
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)
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const (
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BloomFilterMinSize = 10_000_000
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BloomFilterProbability = 0.01
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)
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type BloomMarkSetEnv struct{}
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var _ MarkSetEnv = (*BloomMarkSetEnv)(nil)
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type BloomMarkSet struct {
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salt []byte
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bf *bbloom.Bloom
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}
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var _ MarkSet = (*BloomMarkSet)(nil)
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func NewBloomMarkSetEnv() (*BloomMarkSetEnv, error) {
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return &BloomMarkSetEnv{}, nil
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}
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func (e *BloomMarkSetEnv) Create(name string, sizeHint int64) (MarkSet, error) {
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size := int64(BloomFilterMinSize)
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for size < sizeHint {
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size += BloomFilterMinSize
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}
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salt := make([]byte, 4)
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_, err := rand.Read(salt)
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if err != nil {
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return nil, xerrors.Errorf("error reading salt: %w", err)
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}
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bf, err := bbloom.New(float64(size), BloomFilterProbability)
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if err != nil {
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return nil, xerrors.Errorf("error creating bloom filter: %w", err)
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}
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return &BloomMarkSet{salt: salt, bf: bf}, nil
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}
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func (e *BloomMarkSetEnv) Close() error {
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return nil
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}
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func (s *BloomMarkSet) saltedKey(cid cid.Cid) []byte {
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hash := cid.Hash()
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key := make([]byte, len(s.salt)+len(hash))
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n := copy(key, s.salt)
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copy(key[n:], hash)
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rehash := blake2b.Sum256(key)
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return rehash[:]
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}
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func (s *BloomMarkSet) Mark(cid cid.Cid) error {
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s.bf.Add(s.saltedKey(cid))
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return nil
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}
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func (s *BloomMarkSet) Has(cid cid.Cid) (bool, error) {
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return s.bf.Has(s.saltedKey(cid)), nil
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}
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func (s *BloomMarkSet) Close() error {
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return nil
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}
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