checkpoint

type BlockListener interface {
	// OnBlockSaved is an event fired after block saved to chain db,
	// which means block has been settled in block chain.
	OnBlockSaved(block *types.DposBlock)

	// OnRollbackTo is an event fired during the block chain rollback,
	// since we only tolerance 6 blocks rollback so out max rollback support
	// can be 6 blocks by default.
	OnRollbackTo(height uint32) error
}

type Config struct {
	// EnableHistory is a switch about recording history of snapshots of
	// checkpoints.
	EnableHistory bool

	// HistoryStartHeight defines the height manager should start to record
	// snapshots of checkpoints.
	HistoryStartHeight uint32

	// DataPath defines root directory path of all checkpoint related files.
	DataPath string
}

type ICheckPoint interface {
	common.Serializable
	BlockListener

	// Key is the unique id in manager to identity checkpoints.
	Key() string

	// Snapshot take a snapshot of current state, this should be a deep copy
	// because we are in a async environment.
	Snapshot() ICheckPoint

	// GetHeight returns current height of checkpoint by which determines how to
	// choose between multi-history checkpoints.
	GetHeight() uint32

	// SetHeight set current height of checkpoint by which determines how to
	// choose between multi-history checkpoints.
	SetHeight(uint32)

	// SavePeriod defines how long should we save the checkpoint.
	SavePeriod() uint32

	// EffectivePeriod defines the legal height a checkpoint can take
	// effect.
	EffectivePeriod() uint32

	// DataExtension defines extension of checkpoint related data files.
	DataExtension() string

	// Generator returns a generator to create a checkpoint by a data buffer.
	Generator() func(buf []byte) ICheckPoint

	// LogError will output the specify error with custom log format.
	LogError(err error)

	// Priority defines the priority by which we decide the order when
	// process block and rollback block.
	Priority() Priority

	// OnInit fired after manager successfully loaded default checkpoint.
	OnInit()

	// GetHeight returns initial height checkpoint should start with.
	StartHeight() uint32
}

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

type Priority byte