objectinputstream.java

来自「kaffe Java 解释器语言,源码,Java的子集系统,开放源代码」· Java 代码 · 共 1,847 行 · 第 1/4 页

	  class_name = (String)readObject();
	else
	  class_name = String.valueOf(type_code);
		  
	fields[i] =
	  new ObjectStreamField(field_name, class_name, currentLoader);
      }
	      
    /* Now that fields have been read we may resolve the class
     * (and read annotation if needed). */
    Class clazz = resolveClass(osc);

    boolean oldmode = setBlockDataMode(true);
    osc.setClass(clazz, lookupClass(clazz.getSuperclass()));
    classLookupTable.put(clazz, osc);
    setBlockDataMode(oldmode);

    // find the first non-serializable, non-abstract
    // class in clazz's inheritance hierarchy
    Class first_nonserial = clazz.getSuperclass();
    while (Serializable.class.isAssignableFrom(first_nonserial)
	|| Modifier.isAbstract(first_nonserial.getModifiers()))
	first_nonserial = first_nonserial.getSuperclass();

    osc.firstNonSerializableParent = first_nonserial;
    osc.realClassIsSerializable = Serializable.class.isAssignableFrom(clazz);
    osc.realClassIsExternalizable = Externalizable.class.isAssignableFrom(clazz);

    ObjectStreamField[] stream_fields = osc.fields;
    ObjectStreamField[] real_fields = ObjectStreamClass.lookup(clazz).fields;
    ObjectStreamField[] fieldmapping = new ObjectStreamField[2 * Math.max(stream_fields.length, real_fields.length)];

    int stream_idx = 0;
    int real_idx = 0;
    int map_idx = 0;

    while (stream_idx < stream_fields.length
	   || real_idx < real_fields.length)
      {
	ObjectStreamField stream_field = null;
	ObjectStreamField real_field = null;

	if (stream_idx == stream_fields.length)
	  {
	    real_field = real_fields[real_idx++];
	  }
	else if (real_idx == real_fields.length)
	  {
	    stream_field = stream_fields[stream_idx++];
	  }
	else
	  {
	    int comp_val =
		real_fields[real_idx].compareTo (stream_fields[stream_idx]);

	    if (comp_val < 0)
	      {
		real_field = real_fields[real_idx++];
	      }
	    else if (comp_val > 0)
	      {
		stream_field = stream_fields[stream_idx++];
	      }
	    else
	      {
		stream_field = stream_fields[stream_idx++];
		real_field = real_fields[real_idx++];
		if(stream_field.getType() != real_field.getType())
		    throw new InvalidClassException
			("invalid field type for " + real_field.getName() +
			" in class " + name);
	      }
	  }
	if (stream_field != null)
	  {
	    if (stream_field.getOffset() < 0)
		stream_field = null;
	    else if (!stream_field.isToSet())
		real_field = null;
	  }
	if (real_field != null && !real_field.isToSet())
	    real_field = null;
	/* If some of stream_fields does not correspond to any of real_fields,
	 * or the opposite, then fieldmapping will go short.
	 */
	if (map_idx == fieldmapping.length)
	  {
	    ObjectStreamField[] newfieldmapping =
	      new ObjectStreamField[fieldmapping.length + 2];
	    System.arraycopy(fieldmapping, 0,
	      newfieldmapping, 0, fieldmapping.length);
	    fieldmapping = newfieldmapping;
	  }
	fieldmapping[map_idx++] = stream_field;
	fieldmapping[map_idx++] = real_field;
      }
    osc.fieldMapping = fieldmapping;

    return osc;
  }

  /**
   * Reads the current objects non-transient, non-static fields from
   * the current class from the underlying output stream.
   *
   * This method is intended to be called from within a object's
   * <code>private void readObject (ObjectInputStream)</code>
   * method.
   *
   * @exception ClassNotFoundException The class that an object being
   * read in belongs to cannot be found.
   *
   * @exception NotActiveException This method was called from a
   * context other than from the current object's and current class's
   * <code>private void readObject (ObjectInputStream)</code>
   * method.
   *
   * @exception IOException Exception from underlying
   * <code>OutputStream</code>.
   */
  public void defaultReadObject()
    throws ClassNotFoundException, IOException, NotActiveException
  {
    if (this.currentObject == null || this.currentObjectStreamClass == null)
      throw new NotActiveException("defaultReadObject called by non-active"
				   + " class and/or object");

    if (fieldsAlreadyRead)
      throw new NotActiveException("defaultReadObject called but fields "
				   + "already read from stream (by "
				   + "defaultReadObject or readFields)");

    boolean oldmode = setBlockDataMode(false);
    readFields(this.currentObject, this.currentObjectStreamClass);
    setBlockDataMode(oldmode);

    fieldsAlreadyRead = true;
  }


  /**
   * Registers a <code>ObjectInputValidation</code> to be carried out
   * on the object graph currently being deserialized before it is
   * returned to the original caller of <code>readObject ()</code>.
   * The order of validation for multiple
   * <code>ObjectInputValidation</code>s can be controled using
   * <code>priority</code>.  Validators with higher priorities are
   * called first.
   *
   * @see java.io.ObjectInputValidation
   *
   * @exception InvalidObjectException <code>validator</code> is
   * <code>null</code>
   *
   * @exception NotActiveException an attempt was made to add a
   * validator outside of the <code>readObject</code> method of the
   * object currently being deserialized
   */
  public void registerValidation(ObjectInputValidation validator,
				 int priority)
    throws InvalidObjectException, NotActiveException
  {
    if (this.currentObject == null || this.currentObjectStreamClass == null)
      throw new NotActiveException("registerValidation called by non-active "
				   + "class and/or object");

    if (validator == null)
      throw new InvalidObjectException("attempt to add a null "
				       + "ObjectInputValidation object");

    this.validators.addElement(new ValidatorAndPriority (validator,
							 priority));
  }


  /**
   * Called when a class is being deserialized.  This is a hook to
   * allow subclasses to read in information written by the
   * <code>annotateClass (Class)</code> method of an
   * <code>ObjectOutputStream</code>.
   *
   * This implementation looks up the active call stack for a
   * <code>ClassLoader</code>; if a <code>ClassLoader</code> is found,
   * it is used to load the class associated with <code>osc</code>,
   * otherwise, the default system <code>ClassLoader</code> is used.
   *
   * @exception IOException Exception from underlying
   * <code>OutputStream</code>.
   *
   * @see java.io.ObjectOutputStream#annotateClass (java.lang.Class)
   */
  protected Class resolveClass(ObjectStreamClass osc)
    throws ClassNotFoundException, IOException
  {
    return Class.forName(osc.getName(), true, currentLoader());
  }

  /**
   * This method invokes the method currentClassLoader for the
   * current security manager (or build an empty one if it is not
   * present).
   *
   * @return The most recent non-system ClassLoader on the execution stack.
   * @see java.lang.SecurityManager#currentClassLoader()
   */
  private ClassLoader currentLoader()
  {
    SecurityManager sm = System.getSecurityManager();
    if (sm == null)
      sm = new SecurityManager () {};
    
    return currentClassLoader(sm);
  }

  /**
   * Lookup a class stored in the local hashtable. If it is not
   * use the global lookup function in ObjectStreamClass to build
   * the ObjectStreamClass. This method is requested according to
   * the behaviour detected in the JDK by Kaffe's team.
   *
   * @param clazz Class to lookup in the hash table or for which
   * we must build a descriptor.
   * @return A valid instance of ObjectStreamClass corresponding
   * to the specified class.
   */
  private ObjectStreamClass lookupClass(Class clazz)
  {
    ObjectStreamClass oclazz;

    oclazz = (ObjectStreamClass)classLookupTable.get(clazz);
    if (oclazz == null)
      return ObjectStreamClass.lookup(clazz);
    else
      return oclazz;
  }

  /**
   * Reconstruct class hierarchy the same way
   * {@link java.io.ObjectStreamClass.getObjectStreamClasses(java.lang.Class)} does
   * but using lookupClass instead of ObjectStreamClass.lookup. This
   * dup is necessary localize the lookup table. Hopefully some future
   * rewritings will be able to prevent this.
   *
   * @param clazz This is the class for which we want the hierarchy.
   *
   * @return An array of valid {@link java.io.ObjectStreamClass} instances which
   * represent the class hierarchy for clazz.
   */
  private ObjectStreamClass[] inputGetObjectStreamClasses(Class clazz)
  {
    ObjectStreamClass osc = lookupClass(clazz);

    if (osc == null)
      return new ObjectStreamClass[0];
    else
      {
        Vector oscs = new Vector();

        while (osc != null)
          {
            oscs.addElement(osc);
            osc = osc.getSuper();
	  }

        int count = oscs.size();
	ObjectStreamClass[] sorted_oscs = new ObjectStreamClass[count];

        for (int i = count - 1; i >= 0; i--)
          sorted_oscs[count - i - 1] = (ObjectStreamClass) oscs.elementAt(i);

        return sorted_oscs;
      }
  }

  /**
   * Allows subclasses to resolve objects that are read from the
   * stream with other objects to be returned in their place.  This
   * method is called the first time each object is encountered.
   *
   * This method must be enabled before it will be called in the
   * serialization process.
   *
   * @exception IOException Exception from underlying
   * <code>OutputStream</code>.
   *
   * @see #enableResolveObject(boolean)
   */
  protected Object resolveObject(Object obj) throws IOException
  {
    return obj;
  }


  protected Class resolveProxyClass(String[] intfs)
    throws IOException, ClassNotFoundException
  {
    SecurityManager sm = System.getSecurityManager();
    
    if (sm == null)
      sm = new SecurityManager() {};
    
    ClassLoader cl = currentClassLoader(sm);
    
    Class[] clss = new Class[intfs.length];
    if(cl == null)
      {
	for (int i = 0; i < intfs.length; i++)
	  clss[i] = Class.forName(intfs[i]);
	cl = ClassLoader.getSystemClassLoader();
      }
    else
      for (int i = 0; i < intfs.length; i++)
	clss[i] = cl.loadClass(intfs[i]);
    try 
      {
	return Proxy.getProxyClass(cl, clss);
      } 
    catch (IllegalArgumentException e) 
      {
	throw new ClassNotFoundException(null, e);
      }
  }
  
  /**
   * If <code>enable</code> is <code>true</code> and this object is
   * trusted, then <code>resolveObject (Object)</code> will be called
   * in subsequent calls to <code>readObject (Object)</code>.
   * Otherwise, <code>resolveObject (Object)</code> will not be called.
   *
   * @exception SecurityException This class is not trusted.
   */
  protected boolean enableResolveObject (boolean enable)
    throws SecurityException
  {
    if (enable)
      {
	SecurityManager sm = System.getSecurityManager();
	if (sm != null)
	  sm.checkPermission(new SerializablePermission("enableSubstitution"));
      }

    boolean old_val = this.resolveEnabled;
    this.resolveEnabled = enable;
    return old_val;
  }

  /**
   * Reads stream magic and stream version information from the
   * underlying stream.
   *
   * @exception IOException Exception from underlying stream.
   *
   * @exception StreamCorruptedException An invalid stream magic
   * number or stream version was read from the stream.
   */
  protected void readStreamHeader()
    throws IOException, StreamCorruptedException
  {
    if(dump) dumpElement("STREAM MAGIC ");
    if (this.realInputStream.readShort() != STREAM_MAGIC)
      throw new StreamCorruptedException("Invalid stream magic number");

    if(dump) dumpElementln("STREAM VERSION ");
    if (this.realInputStream.readShort() != STREAM_VERSION)
      throw new StreamCorruptedException("Invalid stream version number");
  }

  public int read() throws IOException
  {
    if (this.readDataFromBlock)
      {
	if (this.blockDataPosition >= this.blockDataBytes)
	  readNextBlock();
	return (this.blockData[this.blockDataPosition++] & 0xff);
      }
    else
      return this.realInputStream.read();
  }

  public int read(byte[] data, int offset, int length) throws IOException
  {
    if (this.readDataFromBlock)
      {
	if (this.blockDataPosition + length > this.blockDataBytes)
	  {
	    int remain = this.blockDataBytes - this.blockDataPosition;
	    if (remain != 0)
	      {
		System.arraycopy(this.blockData, this.blockDataPosition,
				 data, offset, remain);
		offset += remain;
		length -= remain;
	      }
	    readNextBlock ();
	  }

	System.arraycopy(this.blockData, this.blockDataPosition,
			 data, offset, length);
	this.blockDataPosition += length;

	return length;
      }
    else
      return this.realInputStream.read(data, offset, length);
  }

  public int available() throws IOException
  {
    if (this.readDataFromBlock)
      {
	if (this.blockDataPosition >= this.blockDataBytes)
	  readNextBlock ();

	return this.blockDataBytes - this.blockDataPosition;
      }
    else
      return this.realInputStream.available();
  }

  public void close() throws IOException
  {
    this.realInputStream.close();
  }

  public boolean readBoolean() throws IOException
  {
    boolean switchmode = true;
    boolean oldmode = this.readDataFromBlock;
    if (!oldmode || this.blockDataBytes - this.blockDataPosition >= 1)
      switchmode = false;
    if (switchmode)
      oldmode = setBlockDataMode (true);
    boolean value = this.dataInputStream.readBoolean ();
    if (switchmode)
      setBlockDataMode (oldmode);
    return value;
  }

  public byte readByte() throws IOException
  {
    boolean switchmode = true;
    boolean oldmode = this.readDataFromBlock;
    if (!oldmode || this.blockDataBytes - this.blockDataPosition >= 1)
      switchmode = false;
    if (switchmode)
      oldmode = setBlockDataMode(true);
    byte value = this.dataInputStream.readByte();
    if (switchmode)
      setBlockDataMode(oldmode);
    return value;
  }

  public int readUnsignedByte() throws IOException
  {
    boolean switchmode = true;
    boolean oldmode = this.readDataFromBlock;
    if (!oldmode || this.blockDataBytes - this.blockDataPosition >= 1)
      switchmode = false;
    if (switchmode)
      oldmode = setBlockDataMode(true);
    int value = this.dataInputStream.readUnsignedByte();
    if (switchmode)