db

type BackendType string

type Batch interface {
	SetDeleter

	// Write writes the batch, possibly without flushing to disk. Only Close() can be called after,
	// other methods will panic.
	Write() error

	// WriteSync writes the batch and flushes it to disk. Only Close() can be called after, other
	// methods will panic.
	WriteSync() error

	// Close closes the batch. It is idempotent, but any other calls afterwards will panic.
	Close()
}

type DB interface {

	// Get returns nil if key doesn't exist.
	// A nil key is interpreted as an empty byteslice.
	// CONTRACT: key, value readonly []byte
	Get([]byte) ([]byte, error)

	// Has checks if a key exists.
	// A nil key is interpreted as an empty byteslice.
	// CONTRACT: key, value readonly []byte
	Has(key []byte) (bool, error)

	// Set sets the key.
	// A nil key is interpreted as an empty byteslice.
	// CONTRACT: key, value readonly []byte
	Set([]byte, []byte) error
	SetSync([]byte, []byte) error

	// Delete deletes the key.
	// A nil key is interpreted as an empty byteslice.
	// CONTRACT: key readonly []byte
	Delete([]byte) error
	DeleteSync([]byte) error

	// Iterate over a domain of keys in ascending order. End is exclusive.
	// Start must be less than end, or the Iterator is invalid.
	// A nil start is interpreted as an empty byteslice.
	// If end is nil, iterates up to the last item (inclusive).
	// CONTRACT: No writes may happen within a domain while an iterator exists over it.
	// CONTRACT: start, end readonly []byte
	Iterator(start, end []byte) (Iterator, error)

	// Iterate over a domain of keys in descending order. End is exclusive.
	// Start must be less than end, or the Iterator is invalid.
	// If start is nil, iterates up to the first/least item (inclusive).
	// If end is nil, iterates from the last/greatest item (inclusive).
	// CONTRACT: No writes may happen within a domain while an iterator exists over it.
	// CONTRACT: start, end readonly []byte
	ReverseIterator(start, end []byte) (Iterator, error)

	// Closes the connection.
	Close() error

	// Creates a batch for atomic updates. The caller must call Batch.Close.
	NewBatch() Batch

	// For debugging
	Print() error

	// Stats returns a map of property values for all keys and the size of the cache.
	Stats() map[string]string
}

type GoLevelDB struct {
	// contains filtered or unexported fields
}

type Iterator interface {

	// The start & end (exclusive) limits to iterate over.
	// If end < start, then the Iterator goes in reverse order.
	//
	// A domain of ([]byte{12, 13}, []byte{12, 14}) will iterate
	// over anything with the prefix []byte{12, 13}.
	//
	// The smallest key is the empty byte array []byte{} - see BeginningKey().
	// The largest key is the nil byte array []byte(nil) - see EndingKey().
	// CONTRACT: start, end readonly []byte
	Domain() (start []byte, end []byte)

	// Valid returns whether the current position is valid.
	// Once invalid, an Iterator is forever invalid.
	Valid() bool

	// Next moves the iterator to the next sequential key in the database, as
	// defined by order of iteration.
	// If Valid returns false, this method will panic.
	Next()

	// Key returns the key of the cursor.
	// If Valid returns false, this method will panic.
	// CONTRACT: key readonly []byte
	Key() (key []byte)

	// Value returns the value of the cursor.
	// If Valid returns false, this method will panic.
	// CONTRACT: value readonly []byte
	Value() (value []byte)

	Error() error

	// Close releases the Iterator.
	Close()
}

type MemDB struct {
	// contains filtered or unexported fields
}

type PrefixDB struct {
	// contains filtered or unexported fields
}

type SetDeleter interface {
	// Set sets a key/value pair.
	// CONTRACT: key, value readonly []byte
	Set(key, value []byte)

	// Delete deletes a key/value pair.
	// CONTRACT: key readonly []byte
	Delete(key []byte)
}