ioutils

Documentation

Index

• Variables
• func AtomicWriteFile(filename string, data []byte, perm os.FileMode) error
• func FprintfIfNotEmpty(w io.Writer, format, value string) (int, error)
• func FprintfIfTrue(w io.Writer, format string, ok bool) (int, error)
• func HashData(src io.Reader) (string, error)
• func MultiReadSeeker(readers ...io.ReadSeeker) io.ReadSeeker
• func NewAtomicFileWriter(filename string, perm os.FileMode) (io.WriteCloser, error)
• func NewCancelReadCloser(ctx context.Context, in io.ReadCloser) io.ReadCloser
• func NewReadCloserWrapper(r io.Reader, closer func() error) io.ReadCloser
• func NewReaderErrWrapper(r io.Reader, closer func()) io.Reader
• func NewWriteCloserWrapper(r io.Writer, closer func() error) io.WriteCloser
• func NopWriteCloser(w io.Writer) io.WriteCloser
• func TempDir(dir, prefix string) (string, error)
• type BytesPipe
  • func NewBytesPipe() *BytesPipe
  • func (bp *BytesPipe) Close() error
  • func (bp *BytesPipe) CloseWithError(err error) error
  • func (bp *BytesPipe) Read(p []byte) (n int, err error)
  • func (bp *BytesPipe) Write(p []byte) (int, error)
• type NopFlusher
  • func (f *NopFlusher) Flush()
• type NopWriter
  • func (*NopWriter) Write(buf []byte) (int, error)
• type OnEOFReader
  • func (r *OnEOFReader) Close() error
  • func (r *OnEOFReader) Read(p []byte) (n int, err error)
• type WriteCounter
  • func NewWriteCounter(w io.Writer) *WriteCounter
  • func (wc *WriteCounter) Write(p []byte) (count int, err error)
• type WriteFlusher
  • func NewWriteFlusher(w io.Writer) *WriteFlusher
  • func (wf *WriteFlusher) Close() error
  • func (wf *WriteFlusher) Flush()
  • func (wf *WriteFlusher) Flushed() bool
  • func (wf *WriteFlusher) Write(b []byte) (n int, err error)
• Bugs

Variables

var (
	// ErrClosed is returned when Write is called on a closed BytesPipe.
	ErrClosed = errors.New("write to closed BytesPipe")
)

Functions

func AtomicWriteFile

func AtomicWriteFile(filename string, data []byte, perm os.FileMode) error

AtomicWriteFile atomically writes data to a file named by filename.

func FprintfIfNotEmpty

func FprintfIfNotEmpty(w io.Writer, format, value string) (int, error)

FprintfIfNotEmpty prints the string value if it's not empty

func FprintfIfTrue

func FprintfIfTrue(w io.Writer, format string, ok bool) (int, error)

FprintfIfTrue prints the boolean value if it's true

func HashData

func HashData(src io.Reader) (string, error)

HashData returns the sha256 sum of src.

func MultiReadSeeker

func MultiReadSeeker(readers ...io.ReadSeeker) io.ReadSeeker

MultiReadSeeker returns a ReadSeeker that's the logical concatenation of the provided input readseekers. After calling this method the initial position is set to the beginning of the first ReadSeeker. At the end of a ReadSeeker, Read always advances to the beginning of the next ReadSeeker and returns EOF at the end of the last ReadSeeker. Seek can be used over the sum of lengths of all readseekers.

When a MultiReadSeeker is used, no Read and Seek operations should be made on its ReadSeeker components. Also, users should make no assumption on the state of individual readseekers while the MultiReadSeeker is used.

func NewAtomicFileWriter

func NewAtomicFileWriter(filename string, perm os.FileMode) (io.WriteCloser, error)

NewAtomicFileWriter returns WriteCloser so that writing to it writes to a temporary file and closing it atomically changes the temporary file to destination path. Writing and closing concurrently is not allowed.

func NewCancelReadCloser

func NewCancelReadCloser(ctx context.Context, in io.ReadCloser) io.ReadCloser

NewCancelReadCloser creates a wrapper that closes the ReadCloser when the context is cancelled. The returned io.ReadCloser must be closed when it is no longer needed.

func NewReadCloserWrapper

func NewReadCloserWrapper(r io.Reader, closer func() error) io.ReadCloser

NewReadCloserWrapper returns a new io.ReadCloser.

func NewReaderErrWrapper

func NewReaderErrWrapper(r io.Reader, closer func()) io.Reader

NewReaderErrWrapper returns a new io.Reader.

func NewWriteCloserWrapper

func NewWriteCloserWrapper(r io.Writer, closer func() error) io.WriteCloser

NewWriteCloserWrapper returns a new io.WriteCloser.

func NopWriteCloser

func NopWriteCloser(w io.Writer) io.WriteCloser

NopWriteCloser returns a nopWriteCloser.

func TempDir

func TempDir(dir, prefix string) (string, error)

TempDir on Unix systems is equivalent to ioutil.TempDir.

Types

type BytesPipe

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

BytesPipe is io.ReadWriteCloser which works similarly to pipe(queue). All written data may be read at most once. Also, BytesPipe allocates and releases new byte slices to adjust to current needs, so the buffer won't be overgrown after peak loads.

func NewBytesPipe

func NewBytesPipe() *BytesPipe

NewBytesPipe creates new BytesPipe, initialized by specified slice. If buf is nil, then it will be initialized with slice which cap is 64. buf will be adjusted in a way that len(buf) == 0, cap(buf) == cap(buf).

func (*BytesPipe) Close

func (bp *BytesPipe) Close() error

Close causes further reads from a BytesPipe to return immediately.

func (*BytesPipe) CloseWithError

func (bp *BytesPipe) CloseWithError(err error) error

CloseWithError causes further reads from a BytesPipe to return immediately.

func (*BytesPipe) Read

func (bp *BytesPipe) Read(p []byte) (n int, err error)

Read reads bytes from BytesPipe. Data could be read only once.

func (*BytesPipe) Write

func (bp *BytesPipe) Write(p []byte) (int, error)

Write writes p to BytesPipe. It can allocate new []byte slices in a process of writing.

type NopFlusher

type NopFlusher struct{}

NopFlusher represents a type which flush operation is nop.

func (*NopFlusher) Flush

func (f *NopFlusher) Flush()

Flush is a nop operation.

type NopWriter

type NopWriter struct{}

NopWriter represents a type which write operation is nop.

func (*NopWriter) Write

func (*NopWriter) Write(buf []byte) (int, error)

type OnEOFReader

type OnEOFReader struct {
	Rc io.ReadCloser
	Fn func()
}

OnEOFReader wraps an io.ReadCloser and a function the function will run at the end of file or close the file.

func (*OnEOFReader) Close

func (r *OnEOFReader) Close() error

Close closes the file and run the function.

func (*OnEOFReader) Read

func (r *OnEOFReader) Read(p []byte) (n int, err error)

type WriteCounter

type WriteCounter struct {
	Count  int64
	Writer io.Writer
}

WriteCounter wraps a concrete io.Writer and hold a count of the number of bytes written to the writer during a "session". This can be convenient when write return is masked (e.g., json.Encoder.Encode())

func NewWriteCounter

func NewWriteCounter(w io.Writer) *WriteCounter

NewWriteCounter returns a new WriteCounter.

func (*WriteCounter) Write

func (wc *WriteCounter) Write(p []byte) (count int, err error)

type WriteFlusher

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

WriteFlusher wraps the Write and Flush operation ensuring that every write is a flush. In addition, the Close method can be called to intercept Read/Write calls if the targets lifecycle has already ended.

func NewWriteFlusher

func NewWriteFlusher(w io.Writer) *WriteFlusher

NewWriteFlusher returns a new WriteFlusher.

func (*WriteFlusher) Close

func (wf *WriteFlusher) Close() error

Close closes the write flusher, disallowing any further writes to the target. After the flusher is closed, all calls to write or flush will result in an error.

func (*WriteFlusher) Flush

func (wf *WriteFlusher) Flush()

Flush the stream immediately.

func (*WriteFlusher) Flushed

func (wf *WriteFlusher) Flushed() bool

Flushed returns the state of flushed. If it's flushed, return true, or else it return false.

func (*WriteFlusher) Write

func (wf *WriteFlusher) Write(b []byte) (n int, err error)

Notes

Bugs

• Remove this method. Its use is inherently racy. Seems to be used to detect whether or a response code has been issued or not. Another hook should be used instead.