70 lines
1.4 KiB
Go
70 lines
1.4 KiB
Go
package ormkv
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import (
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"bytes"
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"encoding/binary"
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"github.com/cosmos/cosmos-sdk/orm/types/ormerrors"
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"google.golang.org/protobuf/reflect/protoreflect"
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)
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// SeqCodec is the codec for auto-incrementing uint64 primary key sequences.
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type SeqCodec struct {
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tableName protoreflect.FullName
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prefix []byte
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}
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// NewSeqCodec creates a new SeqCodec.
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func NewSeqCodec(tableName protoreflect.FullName, prefix []byte) *SeqCodec {
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return &SeqCodec{tableName: tableName, prefix: prefix}
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}
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var _ EntryCodec = &SeqCodec{}
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func (s SeqCodec) DecodeEntry(k, v []byte) (Entry, error) {
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if !bytes.Equal(k, s.prefix) {
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return nil, ormerrors.UnexpectedDecodePrefix
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}
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x, err := s.DecodeValue(v)
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if err != nil {
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return nil, err
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}
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return &SeqEntry{
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TableName: s.tableName,
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Value: x,
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}, nil
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}
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func (s SeqCodec) EncodeEntry(entry Entry) (k, v []byte, err error) {
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seqEntry, ok := entry.(*SeqEntry)
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if !ok {
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return nil, nil, ormerrors.BadDecodeEntry
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}
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if seqEntry.TableName != s.tableName {
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return nil, nil, ormerrors.BadDecodeEntry
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}
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return s.prefix, s.EncodeValue(seqEntry.Value), nil
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}
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func (s SeqCodec) Prefix() []byte {
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return s.prefix
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}
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func (s SeqCodec) EncodeValue(seq uint64) (v []byte) {
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bz := make([]byte, binary.MaxVarintLen64)
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n := binary.PutUvarint(bz, seq)
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return bz[:n]
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}
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func (s SeqCodec) DecodeValue(v []byte) (uint64, error) {
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if len(v) == 0 {
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return 0, nil
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}
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return binary.ReadUvarint(bytes.NewReader(v))
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}
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