rclone/vendor/storj.io/drpc/drpcwire

package drpcwire

import "storj.io/drpc/drpcwire"

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

Usage

func AppendFrame

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

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

func AppendVarint

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

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

func MarshalError

func MarshalError(err error) []byte

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

func ReadVarint

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 SplitFrame

func SplitFrame(data []byte, atEOF bool) (int, []byte, error)

SplitFrame is used by bufio.Scanner to split frames out of a stream of bytes.

func SplitN

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 default of 1024 is used.

func UnmarshalError

func UnmarshalError(data []byte) error

UnmarshalError unmarshals the marshaled error to one with a code.

type Frame

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

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.

type ID

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

	// Message is the message identifier.
	Message uint64
}

ID represents a packet id.

func (ID) Less

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 (ID) String

func (i ID) String() string

String returns a human readable form of the ID.

type Kind

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 a protobuf.
	KindMessage Kind = 2

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

	// 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 (Kind) String

func (i Kind) String() string

type Packet

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
}

Packet is a single message sent by drpc.

func (Packet) String

func (p Packet) String() string

String returns a human readable form of the packet.

type Reader

type Reader struct {
}

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

func NewReader

func NewReader(r io.Reader) *Reader

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

func (*Reader) ReadPacket

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

ReadPacket 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.

type Writer

type Writer struct {
}

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

func NewWriter

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 (*Writer) Flush

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 (*Writer) WriteFrame

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 (*Writer) WritePacket

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

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