Package io.netty.channel.unix

Class IovArray

java.lang.Object

io.netty.channel.unix.IovArray

All Implemented Interfaces:

ChannelOutboundBuffer.MessageProcessor

public final class IovArray
extends java.lang.Object
implements ChannelOutboundBuffer.MessageProcessor

Represent an array of struct array and so can be passed directly over via JNI without the need to do any more array copies. The buffers are written out directly into direct memory to match the struct iov. See also man writev.

 struct iovec {
   void  *iov_base;
   size_t iov_len;
 };
 

See also Efficient JNI programming IV: Wrapping native data objects.

Field Summary

Fields

Modifier and Type	Field	Description
private static int	ADDRESS_SIZE	The size of an address which should be 8 for 64 bits and 4 for 32 bits.
private int	count
static int	IOV_SIZE	The size of an iovec struct in bytes.
private static int	MAX_CAPACITY	The needed memory to hold up to IOV_MAX iov entries, where IOV_MAX signified the maximum number of iovec structs that can be passed to writev(...).
private long	maxBytes
private ByteBuf	memory
private long	memoryAddress
private long	size

Constructor Summary

Constructors

Constructor	Description
IovArray()
IovArray(ByteBuf memory)

Method Summary

Modifier and Type	Method	Description
private boolean	add(long memoryAddress, long addr, int len)
boolean	add(ByteBuf buf)	Deprecated. Use add(ByteBuf, int, int)
boolean	add(ByteBuf buf, int offset, int len)
void	clear()
int	count()	Returns the number if iov entries.
private static int	idx(int index)
long	maxBytes()	Get the maximum amount of bytes that can be added to this IovArray.
void	maxBytes(long maxBytes)	Set the maximum amount of bytes that can be added to this IovArray via add(ByteBuf, int, int)
long	memoryAddress(int offset)	Returns the memoryAddress for the given offset.
boolean	processMessage(java.lang.Object msg)	Will be called for each flushed message until it either there are no more flushed messages or this method returns false.
void	release()	Release the IovArray.
long	size()	Returns the size in bytes

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

ADDRESS_SIZE

private static final int ADDRESS_SIZE

The size of an address which should be 8 for 64 bits and 4 for 32 bits.

IOV_SIZE

public static final int IOV_SIZE

The size of an iovec struct in bytes. This is calculated as we have 2 entries each of the size of the address.

MAX_CAPACITY

private static final int MAX_CAPACITY

The needed memory to hold up to IOV_MAX iov entries, where IOV_MAX signified the maximum number of iovec structs that can be passed to writev(...).

memoryAddress

private final long memoryAddress

memory

private final ByteBuf memory

count

private int count

size

private long size

maxBytes

private long maxBytes

Constructor Detail

IovArray

public IovArray()

IovArray

public IovArray(ByteBuf memory)

Method Detail

clear

public void clear()

add

@Deprecated
public boolean add(ByteBuf buf)

Deprecated.

Use add(ByteBuf, int, int)

add

public boolean add(ByteBuf buf,
                   int offset,
                   int len)

add

private boolean add(long memoryAddress,
                    long addr,
                    int len)

count

public int count()

Returns the number if iov entries.

size

public long size()

Returns the size in bytes

maxBytes

public void maxBytes(long maxBytes)

Set the maximum amount of bytes that can be added to this IovArray via add(ByteBuf, int, int)

This will not impact the existing state of the IovArray, and only applies to subsequent calls to add(ByteBuf).

In order to ensure some progress is made at least one ByteBuf will be accepted even if it's size exceeds this value.

Parameters:

maxBytes - the maximum amount of bytes that can be added to this IovArray.

maxBytes

public long maxBytes()

Get the maximum amount of bytes that can be added to this IovArray.

Returns:

the maximum amount of bytes that can be added to this IovArray.

memoryAddress

public long memoryAddress(int offset)

Returns the memoryAddress for the given offset.

release

public void release()

Release the IovArray. Once release further using of it may crash the JVM!

processMessage

public boolean processMessage(java.lang.Object msg)
                       throws java.lang.Exception

Description copied from interface: ChannelOutboundBuffer.MessageProcessor

Will be called for each flushed message until it either there are no more flushed messages or this method returns false.

Specified by:

processMessage in interface ChannelOutboundBuffer.MessageProcessor

Throws:

java.lang.Exception

idx

private static int idx(int index)