storage

type CommonTaskRequest struct {
	PeerID      string `json:"peerID,omitempty"`
	TaskID      string `json:"taskID,omitempty"`
	Destination string
}

type GCCallback func(request CommonTaskRequest)

type Manager interface {
	TaskStorageDriver
	// KeepAlive tests if storage is used in given time duration
	util.KeepAlive
	// RegisterTask registers a task in storage driver
	RegisterTask(ctx context.Context, req *RegisterTaskRequest) (TaskStorageDriver, error)
	// RegisterSubTask registers a subtask in storage driver
	RegisterSubTask(ctx context.Context, req *RegisterSubTaskRequest) (TaskStorageDriver, error)
	// UnregisterTask unregisters a task in storage driver
	UnregisterTask(ctx context.Context, req CommonTaskRequest) error
	// FindCompletedTask try to find a completed task for fast path
	FindCompletedTask(taskID string) *ReusePeerTask
	// FindCompletedSubTask try to find a completed subtask for fast path
	FindCompletedSubTask(taskID string) *ReusePeerTask
	// FindPartialCompletedTask try to find a partial completed task for fast path
	FindPartialCompletedTask(taskID string, rg *nethttp.Range) *ReusePeerTask
	// CleanUp cleans all storage data
	CleanUp()
}

type PeerTaskMetadata struct {
	PeerID string `json:"peerID,omitempty"`
	TaskID string `json:"taskID,omitempty"`
}

type PieceMetadata struct {
	Num    int32               `json:"num,omitempty"`
	Md5    string              `json:"md5,omitempty"`
	Offset uint64              `json:"offset,omitempty"`
	Range  http.Range          `json:"range,omitempty"`
	Style  commonv1.PieceStyle `json:"style,omitempty"`
	// time(nanosecond) consumed
	Cost uint64 `json:"cost,omitempty"`
}

type ReadAllPiecesRequest struct {
	PeerTaskMetadata
	Range *http.Range
}

type ReadPieceRequest struct {
	PeerTaskMetadata
	PieceMetadata
}

type Reclaimer interface {
	// CanReclaim indicates whether the storage can be reclaimed
	CanReclaim() bool

	// MarkReclaim marks the storage which will be reclaimed
	MarkReclaim()

	// Reclaim reclaims the storage
	Reclaim() error
}

type RegisterSubTaskRequest struct {
	Parent  PeerTaskMetadata
	SubTask PeerTaskMetadata
	Range   *http.Range
}

type RegisterTaskRequest struct {
	PeerTaskMetadata
	DesiredLocation string
	ContentLength   int64
	TotalPieces     int32
	PieceMd5Sign    string
}

type ReusePeerTask struct {
	PeerTaskMetadata
	ContentLength int64
	TotalPieces   int32
	PieceMd5Sign  string
	Header        *source.Header
	Storage       TaskStorageDriver
}

type StoreRequest struct {
	CommonTaskRequest
	MetadataOnly bool
	// StoreDataOnly stands save file only without save metadata, used in reuse cases
	StoreDataOnly bool
	TotalPieces   int32
	// OriginalOffset stands keep original offset in the target file, if the target file is not original file, return error
	OriginalOffset bool
}

type TaskStorageDriver interface {
	// WritePiece put a piece of a task to storage
	WritePiece(ctx context.Context, req *WritePieceRequest) (int64, error)

	// ReadPiece get a piece data reader of a task from storage
	// return a Reader and a Closer from task data with sought, caller should read bytes and close it.
	// If req.Num is equal to -1, range has a fixed value.
	ReadPiece(ctx context.Context, req *ReadPieceRequest) (io.Reader, io.Closer, error)

	ReadAllPieces(ctx context.Context, req *ReadAllPiecesRequest) (io.ReadCloser, error)

	GetPieces(ctx context.Context, req *commonv1.PieceTaskRequest) (*commonv1.PiecePacket, error)

	GetTotalPieces(ctx context.Context, req *PeerTaskMetadata) (int32, error)

	GetExtendAttribute(ctx context.Context, req *PeerTaskMetadata) (*commonv1.ExtendAttribute, error)

	UpdateTask(ctx context.Context, req *UpdateTaskRequest) error

	// Store stores task data to the target path
	Store(ctx context.Context, req *StoreRequest) error

	ValidateDigest(req *PeerTaskMetadata) error

	IsInvalid(req *PeerTaskMetadata) (bool, error)
}

type UpdateTaskRequest struct {
	PeerTaskMetadata
	ContentLength int64
	TotalPieces   int32
	PieceMd5Sign  string
	Header        *source.Header
}

type WritePieceRequest struct {
	PeerTaskMetadata
	PieceMetadata
	UnknownLength bool
	Reader        io.Reader
	// GenMetadata is used after the last piece in back source case
	GenMetadata func(n int64) (total int32, contentLength int64, gen bool)
}