67 lines
1.6 KiB
Go
67 lines
1.6 KiB
Go
package storage
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import "fmt"
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var (
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ErrorNotFound = fmt.Errorf("not found in DB")
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)
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type Storage interface {
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Write
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// Get retrieves the object `value` named by `key`.
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// Get will return nil if the key is not mapped to a value.
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Get(key []byte) []byte
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// Has returns whether the `key` is mapped to a `value`.
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Has(key []byte) bool
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// Iterator iterates over a DB's key/value pairs in key order.
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Iterator(start, end []byte) Iterator
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// QueryByPrefix iterates over a DB's key/value pairs in key order including prefix.
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Prefix(prefix []byte) Iterator
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NewBatch() Batch
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Close() error
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}
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// Write is the write-side of the storage interface.
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type Write interface {
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// Put stores the object `value` named by `key`.
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Put(key, value []byte)
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// Delete removes the value for given `key`.
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Delete(key []byte)
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}
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type Iterator interface {
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// Next moves the iterator to the next key/value pair.
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// It returns false if the iterator is exhausted.
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Next() bool
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// Prev moves the iterator to the previous key/value pair.
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// It returns false if the iterator is exhausted.
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Prev() bool
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// Seek moves the iterator to the first key/value pair whose key is greater
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// than or equal to the given key.
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// It returns whether such pair exist.
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//
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// It is safe to modify the contents of the argument after Seek returns.
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Seek(key []byte) bool
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// Key returns the key of the current key/value pair, or nil if done.
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Key() []byte
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// Value returns the value of the current key/value pair, or nil if done.
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Value() []byte
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}
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type Batch interface {
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Put(key, value []byte)
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Delete(key []byte)
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Commit()
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}
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