kv

type ByKey []Key

type Getter interface {
	// Get fetches a value for a single key from the database.
	// It return ErrNotFound if key does not exists.
	Get(ctx context.Context, key Key) (Value, error)
}

type Iterator interface {
	base.Iterator
	// Reset the iterator to the starting state. Closed iterator can not reset.
	Reset()
	// Key return current key. Returned value will become invalid on Next or Close.
	// Caller should not modify or store the value - use Clone.
	Key() Key
	// Val return current value. Returned value will become invalid on Next or Close.
	// Caller should not modify or store the value - use Clone.
	Val() Value
}

type IteratorOption interface {
	// ApplyKV applies option to the KV iterator. Implementation may wrap or replace the iterator.
	ApplyKV(it Iterator) Iterator
}

type IteratorOptionFunc func(it Iterator) Iterator

type KV interface {
	base.DB
	Tx(ctx context.Context, rw bool) (Tx, error)
	View(ctx context.Context, fn func(tx Tx) error) error
	Update(ctx context.Context, fn func(tx Tx) error) error
}

type Key [][]byte

type OpenPathFunc func(path string) (KV, error)

type Pair struct {
	Key Key
	Val Value
}

type PrefixIterator interface {
	Iterator
	// WithPrefix implements WithPrefix iterator option.
	// Current iterator will be replaced with a new one and must not be used after this call.
	WithPrefix(pref Key) Iterator
}

type Registration struct {
	base.Registration
	OpenPath OpenPathFunc
}

type Seeker interface {
	Iterator
	// Seek the iterator to a given key. If the key does not exist, the next key is used.
	// Function returns false if there is no key greater or equal to a given one.
	Seek(ctx context.Context, key Key) bool
}

type Tx interface {
	base.Tx
	Getter
	// GetBatch fetches values for multiple keys from the database.
	// Nil element in the slice indicates that key does not exists.
	GetBatch(ctx context.Context, keys []Key) ([]Value, error)
	// Put writes a key-value pair to the database.
	// New value will immediately be visible by Get on the same Tx,
	// but implementation might buffer the write until transaction is committed.
	Put(ctx context.Context, k Key, v Value) error
	// Del removes the key from the database. See Put for consistency guaranties.
	Del(ctx context.Context, k Key) error
	// Scan starts iteration over key-value pairs. Returned results are affected by IteratorOption.
	Scan(ctx context.Context, opts ...IteratorOption) Iterator
}

type Value []byte