buffer

Documentation

Index

• Constants
• type InMessage
  • func (m *InMessage) Consume(n uintptr) unsafe.Pointer
  • func (m *InMessage) ConsumeBytes(n uintptr) []byte
  • func (m *InMessage) Header() *fusekernel.InHeader
  • func (m *InMessage) Init(r io.Reader) error
  • func (m *InMessage) Len() uintptr
• type OutMessage
  • func (m *OutMessage) Append(src []byte)
  • func (m *OutMessage) AppendString(src string)
  • func (m *OutMessage) Bytes() []byte
  • func (m *OutMessage) Grow(n int) unsafe.Pointer
  • func (m *OutMessage) GrowNoZero(n int) unsafe.Pointer
  • func (m *OutMessage) Len() int
  • func (m *OutMessage) OutHeader() *fusekernel.OutHeader
  • func (m *OutMessage) Reset()
  • func (m *OutMessage) ShrinkTo(n int)

Constants

const MaxReadSize = 1 << 20

The maximum read size that we expect to ever see from the kernel, used for calculating the size of out messages.

For 4 KiB pages, this is 1024 KiB (cf. https://github.com/torvalds/linux/blob/15db16837a35d8007cb8563358787412213db25e/fs/fuse/fuse_i.h#L38-L40)

const MaxWriteSize = 1 << 20

The maximum fuse write request size that InMessage can acommodate.

As of kernel 4.20 Linux accepts writes up to 256 pages or 1MiB

const OutMessageHeaderSize = int(unsafe.Sizeof(fusekernel.OutHeader{}))

OutMessageHeaderSize is the size of the leading header in every properly-constructed OutMessage. Reset brings the message back to this size.

Types

type InMessage

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

An incoming message from the kernel, including leading fusekernel.InHeader struct. Provides storage for messages and convenient access to their contents.

func (*InMessage) Consume

func (m *InMessage) Consume(n uintptr) unsafe.Pointer

Consume the next n bytes from the message, returning a nil pointer if there are fewer than n bytes available.

func (*InMessage) ConsumeBytes

func (m *InMessage) ConsumeBytes(n uintptr) []byte

Equivalent to Consume, except returns a slice of bytes. The result will be nil if Consume would fail.

func (*InMessage) Header

func (m *InMessage) Header() *fusekernel.InHeader

Return a reference to the header read in the most recent call to Init.

func (*InMessage) Init

func (m *InMessage) Init(r io.Reader) error

Initialize with the data read by a single call to r.Read. The first call to Consume will consume the bytes directly after the fusekernel.InHeader struct.

func (*InMessage) Len

func (m *InMessage) Len() uintptr

Return the number of bytes left to consume.

type OutMessage

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

OutMessage provides a mechanism for constructing a single contiguous fuse message from multiple segments, where the first segment is always a fusekernel.OutHeader message.

Must be initialized with Reset.

func (*OutMessage) Append

func (m *OutMessage) Append(src []byte)

Append is equivalent to growing by len(src), then copying src over the new segment. Int panics if there is not enough room available.

func (*OutMessage) AppendString

func (m *OutMessage) AppendString(src string)

AppendString is like Append, but accepts string input.

func (*OutMessage) Bytes

func (m *OutMessage) Bytes() []byte

Bytes returns a reference to the current contents of the buffer, including the leading header.

func (*OutMessage) Grow

func (m *OutMessage) Grow(n int) unsafe.Pointer

Grow grows m's buffer by the given number of bytes, returning a pointer to the start of the new segment, which is guaranteed to be zeroed. If there is insufficient space, it returns nil.

func (*OutMessage) GrowNoZero

func (m *OutMessage) GrowNoZero(n int) unsafe.Pointer

GrowNoZero is equivalent to Grow, except the new segment is not zeroed. Use with caution!

func (*OutMessage) Len

func (m *OutMessage) Len() int

Len returns the current size of the message, including the leading header.

func (*OutMessage) OutHeader

func (m *OutMessage) OutHeader() *fusekernel.OutHeader

OutHeader returns a pointer to the header at the start of the message.

func (*OutMessage) Reset

func (m *OutMessage) Reset()

Reset resets m so that it's ready to be used again. Afterward, the contents are solely a zeroed fusekernel.OutHeader struct.

func (*OutMessage) ShrinkTo

func (m *OutMessage) ShrinkTo(n int)

ShrinkTo shrinks m to the given size. It panics if the size is greater than Len() or less than OutMessageHeaderSize.