import "storj.io/drpc/drpcwire"

Package drpcwire provides low level helpers for the drpc wire protocol.

func AppendFrame(buf []byte, fr Frame) []byte

AppendFrame appends a marshaled form of the frame to the provided buffer.

func AppendVarint(buf []byte, x uint64) []byte

AppendVarint appends the varint encoding of x to the buffer and returns it.

func MarshalError(err error) []byte

MarshalError returns a byte form of the error with any error code incorporated.

func ReadVarint(buf []byte) (rem []byte, out uint64, ok bool, err error)

ReadVarint reads a varint encoded integer from the front of buf, returning the remaining bytes, the value, and if there was a success. if ok is false, the returned buffer is the same as the passed in buffer.

func SplitData(buf []byte, n int) (prefix, suffix []byte)

SplitData is used to split a buffer if it is larger than n bytes. If n is zero, a reasonable default is used. If n is less than zero then it does not split.

func SplitN(pkt Packet, n int, cb func(fr Frame) error) error

SplitN splits the marshaled form of the Packet into a number of frames such that each frame is at most n bytes. It calls the callback with every such frame. If n is zero, a reasonable default is used.

func UnmarshalError(data []byte) error

UnmarshalError unmarshals the marshaled error to one with a code.

type Frame struct {
	// Data is the payload of bytes.
	Data []byte

	// ID is used so that the frame can be reconstructed.
	ID ID

	// Kind is the kind of the payload.
	Kind Kind

	// Done is true if this is the last frame for the ID.
	Done bool

	// Control is true if the frame has the control bit set.
	Control bool
}

Frame is a split data frame on the wire.

func ParseFrame(buf []byte) (rem []byte, fr Frame, ok bool, err error)

ParseFrame attempts to parse a frame at the beginning of buf. If successful then rem contains the unparsed data, fr contains the parsed frame, ok will be true, and err will be nil. If there is not enough data for a frame, ok will be false and err will be nil. If the data in the buf is malformed, then an error is returned.

func (fr Frame) String() string

String returns a human readable form of the packet.

type ID struct {
	// Stream is the stream identifier.
	Stream uint64

	// Message is the message identifier.
	Message uint64
}

ID represents a packet id.

func (i ID) Less(j ID) bool

Less returns true if the id is less than the provided one. An ID is less than another if the Stream is less, and if the stream is equal, if the Message is less.

func (i ID) String() string

String returns a human readable form of the ID.

type Kind uint8

Kind is the enumeration of all the different kinds of messages drpc sends.

const (

	// KindInvoke is used to invoke an rpc. The body is the name of the rpc.
	KindInvoke Kind = 1

	// KindMessage is used to send messages. The body is an encoded message.
	KindMessage Kind = 2

	// KindError is used to inform that an error happened. The body is an error
	// with a code attached.
	KindError Kind = 3

	// KindCancel is sent to notify the remote that we have soft canceled.
	KindCancel Kind = 4

	// KindClose is used to inform that the rpc is dead. It has no body.
	KindClose Kind = 5

	// KindCloseSend is used to inform that no more messages will be sent.
	// It has no body.
	KindCloseSend Kind = 6 // body must be empty

	// KindInvokeMetadata includes metadata about the next Invoke packet.
	KindInvokeMetadata Kind = 7
)

func (i Kind) String() string

type Packet struct {
	// Data is the payload of the packet.
	Data []byte

	// ID is the identifier for the packet.
	ID ID

	// Kind is the kind of the packet.
	Kind Kind

	// Control is set to true for packets that are
	// forwards compatible. Unknown or invalid packets
	// with the control bool set should be ignored
	// instead of triggering any errors.
	Control bool
}

Packet is a single message sent by drpc.

func (p Packet) String() string

String returns a human readable form of the packet.

type Reader struct {
}

Reader reconstructs packets from frames read from an io.Reader.

func NewReader(r io.Reader) *Reader

NewReader constructs a Reader to read Packets from the io.Reader.

func NewReaderWithOptions(r io.Reader, opts ReaderOptions) *Reader

NewReaderWithOptions constructs a Reader to read Packets from the io.Reader. It uses the provided options to manage buffering.

func (r *Reader) ReadPacket() (pkt Packet, err error)

ReadPacket reads a packet from the io.Reader. It is equivalent to calling ReadPacketUsing(nil).

func (r *Reader) ReadPacketUsing(buf []byte) (pkt Packet, err error)

ReadPacketUsing reads a packet from the io.Reader. IDs read from frames must be monotonically increasing. When a new ID is read, the old data is discarded. This allows for easier asynchronous interrupts. If the amount of data in the Packet becomes too large, an error is returned. The returned packet's Data field is constructed by appending to the provided buf after it has been resliced to be zero length.

type ReaderOptions struct {
	// MaximumBufferSize controls the maximum size of buffered
	// packet data.
	MaximumBufferSize int
}

ReaderOptions controls configuration settings for a reader.

type Writer struct {
}

Writer is a helper to buffer and write packets and frames to an io.Writer.

func NewWriter(w io.Writer, size int) *Writer

NewWriter returns a Writer that will attempt to buffer size data before sending it to the io.Writer.

func (b *Writer) Empty() bool

Empty returns true if there are no bytes buffered in the writer.

func (b *Writer) Flush() (err error)

Flush forces a flush of any buffered data to the io.Writer. It is a no-op if there is no data in the buffer.

func (b *Writer) Reset() *Writer

Reset clears any pending data in the buffer.

func (b *Writer) WriteFrame(fr Frame) (err error)

WriteFrame appends the frame into the buffer, and if the buffer is larger than the configured size, flushes it.

func (b *Writer) WritePacket(pkt Packet) (err error)

WritePacket writes the packet as a single frame, ignoring any size constraints.