forked from TrueCloudLab/neoneo-go
82 lines
2 KiB
Go
82 lines
2 KiB
Go
package storage
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import (
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"github.com/nspcc-dev/neo-go/pkg/core/storage"
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"github.com/nspcc-dev/neo-go/pkg/util/slice"
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"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
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)
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// Storage iterator options.
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const (
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FindDefault = 0
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FindKeysOnly = 1 << 0
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FindRemovePrefix = 1 << 1
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FindValuesOnly = 1 << 2
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FindDeserialize = 1 << 3
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FindPick0 = 1 << 4
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FindPick1 = 1 << 5
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FindAll = FindDefault | FindKeysOnly | FindRemovePrefix | FindValuesOnly |
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FindDeserialize | FindPick0 | FindPick1
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)
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// Iterator is an iterator state representation.
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type Iterator struct {
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seekCh chan storage.KeyValue
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curr storage.KeyValue
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next bool
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opts int64
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prefix []byte
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}
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// NewIterator creates a new Iterator with the given options for the given channel of store.Seek results.
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func NewIterator(seekCh chan storage.KeyValue, prefix []byte, opts int64) *Iterator {
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return &Iterator{
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seekCh: seekCh,
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opts: opts,
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prefix: slice.Copy(prefix),
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}
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}
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// Next advances the iterator and returns true if Value can be called at the
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// current position.
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func (s *Iterator) Next() bool {
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s.curr, s.next = <-s.seekCh
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return s.next
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}
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// Value returns current iterators value (exact type depends on options this
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// iterator was created with).
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func (s *Iterator) Value() stackitem.Item {
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if !s.next {
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panic("iterator index out of range")
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}
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key := s.curr.Key
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if s.opts&FindRemovePrefix == 0 {
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key = append(s.prefix, key...)
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}
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if s.opts&FindKeysOnly != 0 {
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return stackitem.NewByteArray(key)
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}
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value := stackitem.Item(stackitem.NewByteArray(s.curr.Value))
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if s.opts&FindDeserialize != 0 {
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bs := s.curr.Value
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var err error
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value, err = stackitem.Deserialize(bs)
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if err != nil {
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panic(err)
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}
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}
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if s.opts&FindPick0 != 0 {
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value = value.Value().([]stackitem.Item)[0]
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} else if s.opts&FindPick1 != 0 {
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value = value.Value().([]stackitem.Item)[1]
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}
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if s.opts&FindValuesOnly != 0 {
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return value
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}
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return stackitem.NewStruct([]stackitem.Item{
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stackitem.NewByteArray(key),
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value,
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})
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}
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