[jboss-jira] [JBoss JIRA] Commented: (JBCACHE-1289) VersionAwareMarshalle.objectFromStream implemention uses unreliable InputStream.available

[Elias Ross (JIRA)]

    [ http://jira.jboss.com/jira/browse/JBCACHE-1289?page=comments#action_12398835 ] 
            
Elias Ross commented on JBCACHE-1289:
-------------------------------------


The following change seems to work ok:

Index: C:/src/workspace/JBossCacheSvn/src/main/java/org/jboss/cache/marshall/VersionAwareMarshaller.java
===================================================================
--- C:/src/workspace/JBossCacheSvn/src/main/java/org/jboss/cache/marshall/VersionAwareMarshaller.java	(revision 5309)
+++ C:/src/workspace/JBossCacheSvn/src/main/java/org/jboss/cache/marshall/VersionAwareMarshaller.java	(working copy)
@@ -16,10 +16,16 @@
 import org.jboss.cache.marshall.io.ObjectStreamPool;
 import org.jboss.cache.marshall.io.ReusableObjectOutputStream;
 import org.jboss.cache.util.Util;
+import org.jboss.util.stream.MarshalledValueInputStream;
 
+import static java.io.ObjectStreamConstants.STREAM_MAGIC;
+import static java.io.ObjectStreamConstants.STREAM_VERSION;
+import static java.io.ObjectStreamConstants.TC_BLOCKDATA;
+
 import java.io.InputStream;
 import java.io.ObjectInputStream;
 import java.io.ObjectOutputStream;
+import java.io.PushbackInputStream;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.StringTokenizer;
@@ -207,12 +213,27 @@
       }
    }
 
+   private final static byte[] INIT_BYTES = {(byte) ((STREAM_MAGIC >>> 8) & 0xFF),
+       (byte) ((STREAM_MAGIC) & 0xFF),
+       (byte) ((STREAM_VERSION >>> 8)),
+       (byte) ((STREAM_VERSION) & 0xFF),
+       TC_BLOCKDATA, 0};
+   
+   @Override
    public Object objectFromStream(InputStream is) throws Exception
    {
+	  /* available() may return < really available!
       int avbl = is.available();
       byte[] bytes = new byte[avbl];
       is.read(bytes, 0, avbl);
       return objectFromByteBuffer(bytes);
+      */
+	  PushbackInputStream pis = new PushbackInputStream(is, 100);
+	  pis.unread(INIT_BYTES);
+	  ObjectInputStream ois = new MarshalledValueInputStream(pis);
+	  short versionId = ois.readShort();
+      Marshaller marshaller = getMarshaller(versionId);
+      return marshaller.objectFromObjectStream(ois);
    }
 
    public void objectToObjectStream(Object obj, ObjectOutputStream out, Fqn region) throws Exception


> VersionAwareMarshalle.objectFromStream implemention uses unreliable InputStream.available
> -----------------------------------------------------------------------------------------
>
>                 Key: JBCACHE-1289
>                 URL: http://jira.jboss.com/jira/browse/JBCACHE-1289
>             Project: JBoss Cache
>          Issue Type: Bug
>      Security Level: Public(Everyone can see) 
>            Reporter: Elias Ross
>         Assigned To: Manik Surtani
>
> InputStream.available() may return less than the complete number of bytes available on the stream. The following does not work:
>    @Override
>    public Object objectFromStream(InputStream is) throws Exception
>    {
>       int avbl = is.available(); // MAY RETURN 1 !
>       byte[] bytes = new byte[avbl];
>       is.read(bytes, 0, avbl);
>       return objectFromByteBuffer(bytes);
>    }
> I want to be able to stream objects from the Amazon S3 service. The following does not work either:
> 	  ObjectInputStream ois = new MarshalledValueInputStream(is);
> 	  short versionId = ois.readShort();
>       Marshaller marshaller = getMarshaller(versionId);
>       return marshaller.objectFromObjectStream(ois);
> I'm guessing ReusableObjectInputStream needs to be used and changed to actually support streams, not byte arrays! But I'm not too familiar with the mechanics.

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