109 lines
1.8 KiB
Go
109 lines
1.8 KiB
Go
package cachekv
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import (
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"container/list"
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"errors"
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dbm "github.com/tendermint/tm-db"
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"github.com/cosmos/cosmos-sdk/types/kv"
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)
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// Iterates over iterKVCache items.
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// if key is nil, means it was deleted.
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// Implements Iterator.
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type memIterator struct {
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start, end []byte
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items []*kv.Pair
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ascending bool
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}
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func newMemIterator(start, end []byte, items *list.List, ascending bool) *memIterator {
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itemsInDomain := make([]*kv.Pair, 0)
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var entered bool
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for e := items.Front(); e != nil; e = e.Next() {
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item := e.Value.(*kv.Pair)
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if !dbm.IsKeyInDomain(item.Key, start, end) {
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if entered {
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break
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}
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continue
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}
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itemsInDomain = append(itemsInDomain, item)
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entered = true
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}
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return &memIterator{
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start: start,
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end: end,
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items: itemsInDomain,
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ascending: ascending,
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}
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}
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func (mi *memIterator) Domain() ([]byte, []byte) {
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return mi.start, mi.end
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}
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func (mi *memIterator) Valid() bool {
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return len(mi.items) > 0
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}
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func (mi *memIterator) assertValid() {
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if err := mi.Error(); err != nil {
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panic(err)
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}
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}
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func (mi *memIterator) Next() {
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mi.assertValid()
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if mi.ascending {
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mi.items = mi.items[1:]
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} else {
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mi.items = mi.items[:len(mi.items)-1]
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}
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}
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func (mi *memIterator) Key() []byte {
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mi.assertValid()
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if mi.ascending {
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return mi.items[0].Key
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}
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return mi.items[len(mi.items)-1].Key
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}
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func (mi *memIterator) Value() []byte {
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mi.assertValid()
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if mi.ascending {
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return mi.items[0].Value
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}
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return mi.items[len(mi.items)-1].Value
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}
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func (mi *memIterator) Close() error {
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mi.start = nil
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mi.end = nil
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mi.items = nil
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return nil
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}
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// Error returns an error if the memIterator is invalid defined by the Valid
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// method.
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func (mi *memIterator) Error() error {
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if !mi.Valid() {
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return errors.New("invalid memIterator")
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}
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return nil
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}
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