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¶
Overview ¶
Package extio contains extended io strategies
Index ¶
Constants ¶
const ( // DefaultBufferSize is the default size used for internal buffers (8kb) DefaultBufferSize = 8 << 10 // DefaultReadChanLength is the default size of channels used to buffer communication DefaultReadChanLength = 32 // DefaultWriteChanLength is the default size of channels used to buffer communication DefaultWriteChanLength = 32 )
Variables ¶
var ( // ErrAborted indicates an abort was initiated ErrAborted = errors.New("aborted") // ErrClosed indicates the requested service is closed ErrClosed = errors.New("closed") )
Functions ¶
This section is empty.
Types ¶
type AsyncReader ¶
type AsyncReader struct {
BufferSize int
ChannelSize int
// contains filtered or unexported fields
}
An AsyncReader takes an io.Reader and buffers it in a goroutine subsequent Read([]byte) calls are populated from buffers sent over an internal channel.
func NewAsyncReader ¶
func NewAsyncReader(r io.Reader) *AsyncReader
NewAsyncReader creates a new AsyncReader from the supplied io.Reader and populates it with defaults
func (*AsyncReader) Close ¶
func (ar *AsyncReader) Close() error
Close aborts the buffering goroutine and emits no more data on subsequent Read([]byte) calls
func (*AsyncReader) Read ¶
func (ar *AsyncReader) Read(b []byte) (int, error)
Read takes a byte slice and copies bytes into it and returns number of bytes read and any error encountered. Will emit io.EOF at completion.
func (*AsyncReader) Start ¶
func (ar *AsyncReader) Start()
Start initializes the goroutine that buffers data from the io.Reader
type Broadcaster ¶
type Broadcaster struct {
// ReadChanLength is the size of the channel that each
// BroadcasterReader receives reads from. This allows
// parallel broadcasting without requiring lock-step
// synchronization. This must be set before calling
// NewReader(). (default: 32)
ReadChanLength int
// ReadBufferSize controls the size in bytes of the buffer
// allocated for each read by the Broadcaster. It accomplishes
// buffered reading, as a bufio.ReaderSize does. This must
// not be set after calling Broadcast(). (default: 32kb)
ReadBufferSize int
// contains filtered or unexported fields
}
A Broadcaster takes a single io.Reader and broadcasts reads from it in parallel to all BroadcasterReaders.
func NewBroadcaster ¶
func NewBroadcaster(r io.Reader) *Broadcaster
NewBroadcaster creates a new Broadcaster from the supplied io.Reader and sets ReadChanLength and ReadBufferSize to default values.
func (*Broadcaster) Abort ¶
func (b *Broadcaster) Abort()
Abort aborts the broadcast. Causes the Broadcaster and all BroadcasterReaders to stop reading and return ErrAborted.
func (*Broadcaster) Broadcast ¶
func (b *Broadcaster) Broadcast() error
Broadcast initiates reads from the supplied io.Reader and sends them to the BroadcasterReaders. The bytes read from the io.Reader are sent over channels so the entire sequence is safely concurrent. It returns any error returned by from the underlying io.Reader, except io.EOF. If Abort() was called, returns ErrAborted. All errors are passed to all the BroadcasterReaders. Broadcast will block until all BroadcasterReaders close.
func (*Broadcaster) NewReader ¶
func (b *Broadcaster) NewReader() *BroadcasterReader
NewReader creates a new BroadcasterReader that can be consumed as though it were the original io.Reader supplied to the Broadcaster.
type BroadcasterReader ¶
type BroadcasterReader struct {
// contains filtered or unexported fields
}
A BroadcasterReader satisfies the io.ReadCloser interface and receives it's bytes from the Broadcaster's io.Reader
func (*BroadcasterReader) Close ¶
func (br *BroadcasterReader) Close() error
Close removes the BroadcasterReader from the broadcast stream and causes ErrClosed to be returned on subsequent reads. Close will not block until complete.
type MultiWriter ¶
type MultiWriter struct {
WriteChanLength int
// contains filtered or unexported fields
}
A MultiWriter satisfies the io.WriteCloser interface and allows for multiple io.Writers to be written to concurrently from a single write. The functionality is similar to the io.MultiWriter except that each io.Writer receives it's data in a separate goroutine.
func NewMultiWriter ¶
func NewMultiWriter(ws ...io.Writer) *MultiWriter
NewMultiWriter creates a MultiWriter from the io.Writer(s) specified as args. This only creates the data structure and does not initialize any goroutines.
func (*MultiWriter) Close ¶
func (mw *MultiWriter) Close() error
Close closes each data channel. After the remaining data is drained from the data channels, each io.Writer is checked for a `Close() error` method. If the method is found it is called. This method blocks until all io.Writers have completed consuming their data channels, and optionally closed. The first error encountered is returned, or nil if none.
func (*MultiWriter) Write ¶
func (mw *MultiWriter) Write(data []byte) (int, error)
Write takes a byte slice and writes it to each io.Writer of the MultiWriter. This happens through channels to allow each io.Writer to process the data concurrently. Any alteration of the byte slice by any io.Writers will produce undefined behavior. Write returns the number of bytes written and any error returned by an io.Writer since the first Write. Due to the buffering of channels, this error is not guaranteed to be present for the write that it fails on.
type ScannerWriter ¶
type ScannerWriter struct {
// contains filtered or unexported fields
}
ScannerWriter satisfies the io.WriteCloser interface and turns a series of writes into a stream of tokens that can be processed by a callback.
func NewScannerWriter ¶
func NewScannerWriter(splitFunc bufio.SplitFunc, maxBufSize int, tokenFunc func([]byte) error) *ScannerWriter
NewScannerWriter creates a new ScannerWriter. Arguments are a function that satifies the bufio.SplitFunc type. This is used to parse the incoming byte stream. A maxBufSize, which determines how far to read into the byte stream without finding a token, before throwing an io.ErrShortBuffer. And a tokenFunc that takes the next token identified by splitFunc, and returns an error. An error returned by a splitFunc is returned to the caller of Write().
func (*ScannerWriter) Close ¶
func (sc *ScannerWriter) Close() error
Close closes the ScannerWriter after calling Flush(). Any subsequent writes will return ErrClosed.
func (*ScannerWriter) Flush ¶
func (sc *ScannerWriter) Flush() error
Flush fluses the contents of the buffer to the splitFunc signalling EOF.
func (*ScannerWriter) Write ¶
func (sc *ScannerWriter) Write(data []byte) (int, error)
Write writes the contents of data to the buffer and immediately parses the buffer for as many tokens as splitFunc identifies. Any remaining data is left in the buffer until the next Write or Flush. Returns number of bytes written and any error.
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