cassandra-commits mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Joshua McKenzie (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (CASSANDRA-13680) readBytes needs to clone its data
Date Tue, 25 Jul 2017 13:56:00 GMT

     [ https://issues.apache.org/jira/browse/CASSANDRA-13680?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Joshua McKenzie updated CASSANDRA-13680:
----------------------------------------
    Component/s: Core

> readBytes needs to clone its data
> ---------------------------------
>
>                 Key: CASSANDRA-13680
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-13680
>             Project: Cassandra
>          Issue Type: Bug
>          Components: Core
>            Reporter: Hao Zhong
>
> The code of the ByteBufferUtil_readBytes method is as follow:
> {code}
>  public static ByteBuffer readBytes(ByteBuffer bb, int length)
>     {
>         ByteBuffer copy = bb.duplicate();
>         copy.limit(copy.position() + length);
>         bb.position(bb.position() + length);
>         return copy;
>     }
> {code}
> I found that CASSANDRA-3179 fixed a related bug. The buggy code is as follow:
> {code}
>  public synchronized ByteBuffer readBytes(int length) throws IOException
>     {
>         int remaining = buffer.remaining() - position;
>         if (length > remaining)
>             throw new IOException(String.format("mmap segment underflow; remaining is
%d but %d requested",
>                                                 remaining, length));
>         ByteBuffer bytes = buffer.duplicate();
>         bytes.position(buffer.position() + position).limit(buffer.position() + position
+ length);
>         position += length;
>         return bytes;
>     }
> {code}
> The fixed code is:
> {code}
>  public synchronized ByteBuffer readBytes(int length) throws IOException
>     {
>         int remaining = buffer.remaining() - position;
>         if (length > remaining)
>             throw new IOException(String.format("mmap segment underflow; remaining is
%d but %d requested",
>                                                 remaining, length));
>         if (length == 0)
>             return ByteBufferUtil.EMPTY_BYTE_BUFFER;
>         ByteBuffer bytes = buffer.duplicate();
>         bytes.position(buffer.position() + position).limit(buffer.position() + position
+ length);
>         position += length;
>         // we have to copy the data in case we unreference the underlying sstable.  See
CASSANDRA-3179
>         ByteBuffer clone = ByteBuffer.allocate(bytes.remaining());
>         clone.put(bytes);
>         clone.flip();
>         return clone;
>     }
> {code}
> The ByteBufferUtil_readBytes method may be modified in the same way to handle the similar
problem. 



--
This message was sent by Atlassian JIRA
(v6.4.14#64029)

---------------------------------------------------------------------
To unsubscribe, e-mail: commits-unsubscribe@cassandra.apache.org
For additional commands, e-mail: commits-help@cassandra.apache.org


Mime
View raw message