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/* Copyright (c) 2008-2018, Nathan Sweet
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following
* conditions are met:
*
* - Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
* - Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials provided with the distribution.
* - Neither the name of Esoteric Software nor the names of its contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,
* BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
* SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */
package com.esotericsoftware.kryo.serializers;
import static com.esotericsoftware.kryo.util.Util.*;
import static com.esotericsoftware.minlog.Log.*;
import com.esotericsoftware.kryo.Kryo;
import com.esotericsoftware.kryo.KryoException;
import com.esotericsoftware.kryo.Registration;
import com.esotericsoftware.kryo.io.Input;
import com.esotericsoftware.kryo.io.InputChunked;
import com.esotericsoftware.kryo.io.Output;
import com.esotericsoftware.kryo.io.OutputChunked;
import com.esotericsoftware.kryo.util.ObjectMap;
/** Serializes objects using direct field assignment, providing both forward and backward compatibility. This means fields can be
* added or removed without invalidating previously serialized bytes. Renaming or changing the type of a field is not supported.
* Like {@link FieldSerializer}, it can serialize most classes without needing annotations.
*
* The forward and backward compatibility and serialization performance depend on
* {@link CompatibleFieldSerializerConfig#setReadUnknownFieldData(boolean)} and
* {@link CompatibleFieldSerializerConfig#setChunkedEncoding(boolean)}. Additionally, the first time the class is encountered in
* the serialized bytes, a simple schema is written containing the field name strings.
*
* Note that the field data is identified by name. If a super class has a field with the same name as a subclass,
* {@link CompatibleFieldSerializerConfig#setExtendedFieldNames(boolean)} must be true.
* @author Nathan Sweet */
public class CompatibleFieldSerializer extends FieldSerializer {
static private final int binarySearchThreshold = 32;
private CompatibleFieldSerializerConfig config;
public CompatibleFieldSerializer (Kryo kryo, Class type) {
this(kryo, type, new CompatibleFieldSerializerConfig());
}
public CompatibleFieldSerializer (Kryo kryo, Class type, CompatibleFieldSerializerConfig config) {
super(kryo, type, config);
this.config = config;
}
public void write (Kryo kryo, Output output, T object) {
int pop = pushTypeVariables();
CachedField[] fields = cachedFields.fields;
ObjectMap context = kryo.getGraphContext();
if (!context.containsKey(this)) {
if (TRACE) trace("kryo", "Write fields for class: " + type.getName());
context.put(this, null);
output.writeVarInt(fields.length, true);
for (int i = 0, n = fields.length; i < n; i++) {
if (TRACE) trace("kryo", "Write field name: " + fields[i].name + pos(output.position()));
output.writeString(fields[i].name);
}
}
boolean chunked = config.chunked, readUnknownTagData = config.readUnknownFieldData;
Output fieldOutput;
OutputChunked outputChunked = null;
if (chunked)
fieldOutput = outputChunked = new OutputChunked(output, config.chunkSize);
else
fieldOutput = output;
for (int i = 0, n = fields.length; i < n; i++) {
CachedField cachedField = fields[i];
if (TRACE) log("Write", cachedField, output.position());
// Write the value class so the field data can be read even if the field is removed.
if (readUnknownTagData) {
Class valueClass = null;
try {
if (object != null) {
Object value = cachedField.field.get(object);
if (value != null) valueClass = value.getClass();
}
} catch (IllegalAccessException ex) {
}
kryo.writeClass(fieldOutput, valueClass);
if (valueClass == null) {
if (chunked) outputChunked.endChunk();
continue;
}
cachedField.setCanBeNull(false);
cachedField.setValueClass(valueClass);
}
cachedField.write(fieldOutput, object);
if (chunked) outputChunked.endChunk();
}
if (pop > 0) popTypeVariables(pop);
}
public T read (Kryo kryo, Input input, Class type) {
int pop = pushTypeVariables();
T object = create(kryo, input, type);
kryo.reference(object);
CachedField[] fields = (CachedField[])kryo.getGraphContext().get(this);
if (fields == null) fields = readFields(kryo, input);
boolean chunked = config.chunked, readUnknownTagData = config.readUnknownFieldData;
Input fieldInput;
InputChunked inputChunked = null;
if (chunked)
fieldInput = inputChunked = new InputChunked(input, config.chunkSize);
else
fieldInput = input;
for (int i = 0, n = fields.length; i < n; i++) {
CachedField cachedField = fields[i];
if (readUnknownTagData) {
Registration registration;
try {
registration = kryo.readClass(fieldInput);
} catch (KryoException ex) {
if (!chunked)
throw new KryoException("Unable to read unknown data (unknown type). (" + getType().getName() + ")", ex);
if (DEBUG) debug("kryo", "Unable to read unknown data (unknown type).", ex);
inputChunked.nextChunk();
continue;
}
if (registration == null) {
if (chunked) inputChunked.nextChunk();
continue;
}
Class valueClass = registration.getType();
if (cachedField == null) {
// Read unknown data in case it is a reference.
if (TRACE) trace("kryo", "Read unknown data, type: " + className(valueClass) + pos(input.position()));
try {
kryo.readObject(fieldInput, valueClass);
} catch (KryoException ex) {
if (!chunked) throw new KryoException(
"Unable to read unknown data, type: " + className(valueClass) + " (" + getType().getName() + ")", ex);
if (DEBUG) debug("kryo", "Unable to read unknown data, type: " + className(valueClass), ex);
}
if (chunked) inputChunked.nextChunk();
continue;
}
cachedField.setCanBeNull(false);
cachedField.setValueClass(valueClass);
} else if (cachedField == null) {
if (!chunked) throw new KryoException("Unknown field. (" + getType().getName() + ")");
if (TRACE) trace("kryo", "Skip unknown field.");
inputChunked.nextChunk();
continue;
}
if (TRACE) log("Read", cachedField, input.position());
cachedField.read(fieldInput, object);
if (chunked) inputChunked.nextChunk();
}
if (pop > 0) popTypeVariables(pop);
return object;
}
private CachedField[] readFields (Kryo kryo, Input input) {
if (TRACE) trace("kryo", "Read fields for class: " + type.getName());
int length = input.readVarInt(true);
String[] names = new String[length];
for (int i = 0; i < length; i++) {
names[i] = input.readString();
if (TRACE) trace("kryo", "Read field name: " + names[i]);
}
CachedField[] fields = new CachedField[length];
CachedField[] allFields = cachedFields.fields;
if (length < binarySearchThreshold) {
outer:
for (int i = 0; i < length; i++) {
String schemaName = names[i];
for (int ii = 0, nn = allFields.length; ii < nn; ii++) {
if (allFields[ii].name.equals(schemaName)) {
fields[i] = allFields[ii];
continue outer;
}
}
if (TRACE) trace("kryo", "Unknown field will be skipped: " + schemaName);
}
} else {
int low, mid, high, compare;
int lastFieldIndex = allFields.length;
outer:
for (int i = 0; i < length; i++) {
String schemaName = names[i];
low = 0;
high = lastFieldIndex;
while (low <= high) {
mid = (low + high) >>> 1;
compare = schemaName.compareTo(allFields[mid].name);
if (compare < 0)
high = mid - 1;
else if (compare > 0)
low = mid + 1;
else {
fields[i] = allFields[mid];
continue outer;
}
}
if (TRACE) trace("kryo", "Unknown field will be skipped: " + schemaName);
}
}
kryo.getGraphContext().put(this, fields);
return fields;
}
public CompatibleFieldSerializerConfig getCompatibleFieldSerializerConfig () {
return config;
}
/** Configuration for CompatibleFieldSerializer instances. */
static public class CompatibleFieldSerializerConfig extends FieldSerializerConfig {
boolean readUnknownFieldData = true, chunked;
int chunkSize = 1024;
public CompatibleFieldSerializerConfig clone () {
return (CompatibleFieldSerializerConfig)super.clone(); // Clone is ok as we have only primitive fields.
}
/** When false and encountering an unknown field, an exception is thrown or, if {@link #setChunkedEncoding(boolean) chunked
* encoding} is enabled, the data is skipped.
*
* When true, the type of each field value is written before the value. When an unknown field is encountered, an attempt to
* read the data is made so if it is a reference then any other values in the object graph referencing that data can be
* deserialized. If reading the data fails (eg the class is unknown or has been removed) then an exception is thrown or, if
* {@link #setChunkedEncoding(boolean) chunked encoding} is enabled, the data is skipped.
*
* In either case, if the data is skipped and {@link Kryo#setReferences(boolean) references} are enabled, then any
* references in the skipped data are not read and further deserialization receive the wrong references and fail.
*
* Default is true. */
public void setReadUnknownFieldData (boolean readUnknownTagData) {
this.readUnknownFieldData = readUnknownTagData;
}
public boolean getReadUnknownTagData () {
return readUnknownFieldData;
}
/** When true, fields are written with chunked encoding to allow unknown field data to be skipped. Default is false.
* @see #setReadUnknownFieldData(boolean) */
public void setChunkedEncoding (boolean chunked) {
this.chunked = chunked;
if (TRACE) trace("kryo", "CompatibleFieldSerializerConfig setChunked: " + chunked);
}
public boolean getChunkedEncoding () {
return chunked;
}
/** The maximum size of each chunk for chunked encoding. Default is 1024. */
public void setChunkSize (int chunkSize) {
this.chunkSize = chunkSize;
if (TRACE) trace("kryo", "CompatibleFieldSerializerConfig setChunkSize: " + chunkSize);
}
public int getChunkSize () {
return chunkSize;
}
}
}