99 lines
2.7 KiB
Go
99 lines
2.7 KiB
Go
package orm
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import (
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"encoding/binary"
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storetypes "cosmossdk.io/core/store"
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errorsmod "cosmossdk.io/errors"
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"cosmossdk.io/x/group/errors"
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"cosmossdk.io/x/group/internal/orm/prefixstore"
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)
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// sequenceStorageKey is a fix key to read/ write data on the storage layer
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var sequenceStorageKey = []byte{0x1}
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// sequence is a persistent unique key generator based on a counter.
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type Sequence struct {
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prefix byte
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}
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func NewSequence(prefix byte) Sequence {
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return Sequence{
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prefix: prefix,
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}
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}
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// NextVal increments and persists the counter by one and returns the value.
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func (s Sequence) NextVal(store storetypes.KVStore) uint64 {
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pStore := prefixstore.New(store, []byte{s.prefix})
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v, err := pStore.Get(sequenceStorageKey)
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if err != nil {
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panic(err)
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}
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seq := DecodeSequence(v)
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seq++
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err = pStore.Set(sequenceStorageKey, EncodeSequence(seq))
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if err != nil {
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panic(err)
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}
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return seq
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}
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// CurVal returns the last value used. 0 if none.
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func (s Sequence) CurVal(store storetypes.KVStore) uint64 {
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pStore := prefixstore.New(store, []byte{s.prefix})
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v, err := pStore.Get(sequenceStorageKey)
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if err != nil {
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panic(err)
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}
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return DecodeSequence(v)
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}
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// PeekNextVal returns the CurVal + increment step. Not persistent.
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func (s Sequence) PeekNextVal(store storetypes.KVStore) uint64 {
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pStore := prefixstore.New(store, []byte{s.prefix})
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v, err := pStore.Get(sequenceStorageKey)
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if err != nil {
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panic(err)
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}
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return DecodeSequence(v) + 1
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}
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// InitVal sets the start value for the sequence. It must be called only once on an empty DB.
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// Otherwise an error is returned when the key exists. The given start value is stored as current
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// value.
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//
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// It is recommended to call this method only for a sequence start value other than `1` as the
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// method consumes unnecessary gas otherwise. A scenario would be an import from genesis.
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func (s Sequence) InitVal(store storetypes.KVStore, seq uint64) error {
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pStore := prefixstore.New(store, []byte{s.prefix})
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has, err := pStore.Has(sequenceStorageKey)
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if err != nil {
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return err
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}
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if has {
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return errorsmod.Wrap(errors.ErrORMUniqueConstraint, "already initialized")
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}
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return pStore.Set(sequenceStorageKey, EncodeSequence(seq))
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}
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// DecodeSequence converts the binary representation into an Uint64 value.
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func DecodeSequence(bz []byte) uint64 {
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if bz == nil {
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return 0
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}
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val := binary.BigEndian.Uint64(bz)
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return val
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}
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// EncodedSeqLength number of bytes used for the binary representation of a sequence value.
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const EncodedSeqLength = 8
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// EncodeSequence converts the sequence value into the binary representation.
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func EncodeSequence(val uint64) []byte {
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bz := make([]byte, EncodedSeqLength)
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binary.BigEndian.PutUint64(bz, val)
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return bz
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}
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