Package org.apache.flink.runtime.io.network.buffer

Class FileRegionBuffer

java.lang.Object
org.apache.flink.shaded.netty4.io.netty.util.AbstractReferenceCounted
org.apache.flink.shaded.netty4.io.netty.channel.DefaultFileRegion
org.apache.flink.runtime.io.network.buffer.FileRegionBuffer
All Implemented Interfaces:
Buffer, org.apache.flink.shaded.netty4.io.netty.channel.FileRegion, org.apache.flink.shaded.netty4.io.netty.util.ReferenceCounted
public class FileRegionBuffer extends org.apache.flink.shaded.netty4.io.netty.channel.DefaultFileRegion implements Buffer
This class represents a chunk of data in a file channel. Its purpose is to be passed to the netty code and to be written to the socket via the zero-copy direct transfer capabilities of FileChannel.transferTo(long, long, WritableByteChannel).

This class implements Buffer mainly for compatible with existing usages. It can be thought of as a "lazy buffer" that does not hold the data directly, although the data can be fetches as a read-only ByteBuffer when needed, for example in local input channels. See readInto(MemorySegment) and getNioBufferReadable(). Because this buffer is read-only, the modification methods (and methods that give a writable buffer) throw UnsupportedOperationException.

This class extends from Netty's DefaultFileRegion, similar as the NetworkBuffer extends from Netty's ByteBuf. That way we can pass both of them to Netty in the same way, and Netty will internally treat them appropriately.

  • Constructor Details

    • FileRegionBuffer

      public FileRegionBuffer(FileChannel fileChannel, long fileChannelPosition, int bufferSize, Buffer.DataType dataType, boolean isCompressed)

  • Method Details

    • isBuffer

      public boolean isBuffer()
      Description copied from interface: Buffer
      Returns whether this buffer represents a buffer or an event.
      Specified by:
      isBuffer in interface Buffer
      Returns:
      true if this is a real buffer, false if this is an event

    • getMemorySegment

      public org.apache.flink.core.memory.MemorySegment getMemorySegment()
      Description copied from interface: Buffer
      Returns the underlying memory segment. This method is dangerous since it ignores read only protections and omits slices. Use it only along the Buffer.getMemorySegmentOffset().

      This method will be removed in the future. For writing use BufferBuilder.

      Specified by:
      getMemorySegment in interface Buffer
      Returns:
      the memory segment backing this buffer

    • getMemorySegmentOffset

      public int getMemorySegmentOffset()
      Description copied from interface: Buffer
      This method will be removed in the future. For writing use BufferBuilder.
      Specified by:
      getMemorySegmentOffset in interface Buffer
      Returns:
      the offset where this (potential slice) Buffer's data start in the underlying memory segment.

    • readOnlySlice

      public ReadOnlySlicedNetworkBuffer readOnlySlice()
      Description copied from interface: Buffer
      Returns a read-only slice of this buffer's readable bytes, i.e. between Buffer.getReaderIndex() and Buffer.getSize().

      Reader and writer indices as well as markers are not shared. Reference counters are shared but the slice is not retained automatically.

      Specified by:
      readOnlySlice in interface Buffer
      Returns:
      a read-only sliced buffer

    • readOnlySlice

      public ReadOnlySlicedNetworkBuffer readOnlySlice(int index, int length)
      Description copied from interface: Buffer
      Returns a read-only slice of this buffer.

      Reader and writer indices as well as markers are not shared. Reference counters are shared but the slice is not retained automatically.

      Specified by:
      readOnlySlice in interface Buffer
      Parameters:
      index - the index to start from
      length - the length of the slice
      Returns:
      a read-only sliced buffer

    • getMaxCapacity

      public int getMaxCapacity()
      Description copied from interface: Buffer
      Returns the maximum size of the buffer, i.e. the capacity of the underlying MemorySegment.
      Specified by:
      getMaxCapacity in interface Buffer
      Returns:
      size of the buffer

    • getReaderIndex

      public int getReaderIndex()
      Description copied from interface: Buffer
      Returns the reader index of this buffer.

      This is where readable (unconsumed) bytes start in the backing memory segment.

      Specified by:
      getReaderIndex in interface Buffer
      Returns:
      reader index (from 0 (inclusive) to the size of the backing MemorySegment (inclusive))

    • setReaderIndex

      public void setReaderIndex(int readerIndex) throws IndexOutOfBoundsException
      Description copied from interface: Buffer
      Sets the reader index of this buffer.
      Specified by:
      setReaderIndex in interface Buffer
      Throws:
      IndexOutOfBoundsException - if the index is less than 0 or greater than Buffer.getSize()

    • getNioBufferReadable

      public ByteBuffer getNioBufferReadable()
      This method is only called by tests and by event-deserialization, like checkpoint barriers. Because such events are not used for bounded intermediate results, this method currently executes only in tests.
      Specified by:
      getNioBufferReadable in interface Buffer
      Returns:
      byte buffer sharing the contents of the underlying memory segment

    • getNioBuffer

      public ByteBuffer getNioBuffer(int index, int length) throws IndexOutOfBoundsException
      Description copied from interface: Buffer
      Gets a new ByteBuffer instance wrapping this buffer's bytes.

      Please note that neither read nor write index are updated by the returned buffer.

      Specified by:
      getNioBuffer in interface Buffer
      Returns:
      byte buffer sharing the contents of the underlying memory segment
      Throws:
      IndexOutOfBoundsException - if the indexes are not without the buffer's bounds
      See Also:

    • asByteBuf

      public org.apache.flink.shaded.netty4.io.netty.buffer.ByteBuf asByteBuf()
      Specified by:
      asByteBuf in interface Buffer
      Returns:
      self as ByteBuf implementation.

    • setSize

      public void setSize(int writerIndex)
      Description copied from interface: Buffer
      Sets the size of the written data, i.e. the writer index, of this buffer.
      Specified by:
      setSize in interface Buffer

    • getSize

      public int getSize()
      Description copied from interface: Buffer
      Returns the size of the written data, i.e. the writer index, of this buffer.

      This is where writable bytes start in the backing memory segment.

      Specified by:
      getSize in interface Buffer
      Returns:
      writer index (from 0 (inclusive) to the size of the backing MemorySegment (inclusive))

    • readableBytes

      public int readableBytes()
      Description copied from interface: Buffer
      Returns the number of readable bytes (same as Buffer.getSize() - Buffer.getReaderIndex()).
      Specified by:
      readableBytes in interface Buffer

    • setAllocator

      public void setAllocator(org.apache.flink.shaded.netty4.io.netty.buffer.ByteBufAllocator allocator)
      Description copied from interface: Buffer
      Sets the buffer allocator for use in netty.
      Specified by:
      setAllocator in interface Buffer
      Parameters:
      allocator - netty buffer allocator

    • getRecycler

      public BufferRecycler getRecycler()
      Description copied from interface: Buffer
      Gets the buffer's recycler.
      Specified by:
      getRecycler in interface Buffer
      Returns:
      buffer recycler

    • setRecycler

      public void setRecycler(BufferRecycler bufferRecycler)
      Description copied from interface: Buffer
      Sets the buffer's recycler.

      Note that updating the recycler is an unsafe operation and this method cannot guarantee thread safety. It is important for the caller to fully understand the consequences of calling this method. Incorrectly updating the buffer recycler can result in a leak of the buffer due to using a wrong recycler to recycle buffer. Therefore, be careful when calling this method.

      Specified by:
      setRecycler in interface Buffer
      Parameters:
      bufferRecycler - the new buffer recycler

    • recycleBuffer

      public void recycleBuffer()
      Description copied from interface: Buffer
      Releases this buffer once, i.e. reduces the reference count and recycles the buffer if the reference count reaches 0.
      Specified by:
      recycleBuffer in interface Buffer
      See Also:

    • isRecycled

      public boolean isRecycled()
      Description copied from interface: Buffer
      Returns whether this buffer has been recycled or not.
      Specified by:
      isRecycled in interface Buffer
      Returns:
      true if already recycled, false otherwise

    • retainBuffer

      public FileRegionBuffer retainBuffer()
      Description copied from interface: Buffer
      Retains this buffer for further use, increasing the reference counter by 1.
      Specified by:
      retainBuffer in interface Buffer
      Returns:
      this instance (for chained calls)
      See Also:

    • isCompressed

      public boolean isCompressed()
      Specified by:
      isCompressed in interface Buffer
      Returns:
      whether the buffer is compressed or not.

    • setCompressed

      public void setCompressed(boolean isCompressed)
      Description copied from interface: Buffer
      Tags the buffer as compressed or uncompressed.
      Specified by:
      setCompressed in interface Buffer

    • getDataType

      public Buffer.DataType getDataType()
      Description copied from interface: Buffer
      Gets the type of data this buffer represents.
      Specified by:
      getDataType in interface Buffer

    • setDataType

      public void setDataType(Buffer.DataType dataType)
      Description copied from interface: Buffer
      Sets the type of data this buffer represents.
      Specified by:
      setDataType in interface Buffer

    • deallocate

      public void deallocate()
      Overrides:
      deallocate in class org.apache.flink.shaded.netty4.io.netty.channel.DefaultFileRegion

    • readInto

      public Buffer readInto(org.apache.flink.core.memory.MemorySegment segment) throws IOException
      Throws:
      IOException