statemgmt

type ChaincodeStateDelta struct {
	ChaincodeID string
	UpdatedKVs  map[string]*UpdatedValue
}

type HashableState interface {

	// Initialize this gives a chance to initialize. For instance, state implementation can load some data from DB
	Initialize(configs map[string]interface{}) error

	// Get get the value from DB
	Get(chaincodeID string, key string) ([]byte, error)

	// PrepareWorkingSet passes a stateDelta that captures the changes that needs to be applied to the state
	PrepareWorkingSet(stateDelta *StateDelta) error

	// ComputeCryptoHash state implementation to compute crypto-hash of state
	// assuming the stateDelta (passed in PrepareWorkingSet method) is to be applied
	ComputeCryptoHash() ([]byte, error)

	// AddChangesForPersistence state implementation to add all the key-value pair that it needs
	// to persist for committing the  stateDelta (passed in PrepareWorkingSet method) to DB.
	// In addition to the information in the StateDelta, the implementation may also want to
	// persist intermediate results for faster crypto-hash computation
	AddChangesForPersistence(writeBatch *gorocksdb.WriteBatch) error

	// ClearWorkingSet state implementation may clear any data structures that it may have constructed
	// for computing cryptoHash and persisting the changes for the stateDelta (passed in PrepareWorkingSet method)
	ClearWorkingSet(changesPersisted bool)

	// GetStateSnapshotIterator state implementation to provide an iterator that is supposed to give
	// All the key-value of global state. A particular implementation may need to remove additional information
	// that the implementation keeps for faster crypto-hash computation. For instance, filter a few of the
	// key-values or remove some data from particular key-values.
	GetStateSnapshotIterator(snapshot *gorocksdb.Snapshot) (StateSnapshotIterator, error)

	// GetRangeScanIterator - state implementation to provide an iterator that is supposed to give
	// All the key-values for a given chaincodeID such that a return key should be lexically greater than or
	// equal to startKey and less than or equal to endKey. If the value for startKey parameter is an empty string
	// startKey is assumed to be the smallest key available in the db for the chaincodeID. Similarly, an empty string
	// for endKey parameter assumes the endKey to be the greatest key available in the db for the chaincodeID
	GetRangeScanIterator(chaincodeID string, startKey string, endKey string) (RangeScanIterator, error)

	// PerfHintKeyChanged state implementation may be provided with some hints before (e.g., during tx execution)
	// the StateDelta is prepared and passed in PrepareWorkingSet method.
	// A state implementation may use this hint for prefetching relevant data so as if this could improve
	// the performance of ComputeCryptoHash method (when gets called at a later time)
	PerfHintKeyChanged(chaincodeID string, key string)
}

type RangeScanIterator interface {

	// Next moves to next key-value. Returns true if next key-value exists
	Next() bool

	// GetKeyValue returns next key-value
	GetKeyValue() (string, []byte)

	// Close releases resources occupied by the iterator
	Close()
}

type StateDelta struct {
	ChaincodeStateDeltas map[string]*ChaincodeStateDelta
	// RollBackwards allows one to contol whether this delta will roll the state
	// forwards or backwards.
	RollBackwards bool
}

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

type StateSnapshotIterator interface {

	// Next moves to next key-value. Returns true if next key-value exists
	Next() bool

	// GetRawKeyValue returns next key-value
	GetRawKeyValue() ([]byte, []byte)

	// Close releases resources occupied by the iterator
	Close()
}

type UpdatedValue struct {
	Value         []byte
	PreviousValue []byte
}