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Revert to core reflection (#815)
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Restores Android API <= 26 compatibility
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Julia Boes committed Apr 1, 2021
1 parent 4a4cb18 commit c422852
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Showing 2 changed files with 31 additions and 45 deletions.
74 changes: 30 additions & 44 deletions src/com/esotericsoftware/kryo/serializers/RecordSerializer.java
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Original file line number Diff line number Diff line change
Expand Up @@ -21,16 +21,14 @@

import static com.esotericsoftware.minlog.Log.TRACE;
import static com.esotericsoftware.minlog.Log.trace;
import static java.lang.invoke.MethodType.methodType;

import com.esotericsoftware.kryo.Kryo;
import com.esotericsoftware.kryo.KryoException;
import com.esotericsoftware.kryo.io.Input;
import com.esotericsoftware.kryo.io.Output;

import java.lang.invoke.MethodHandle;
import java.lang.invoke.MethodHandles;
import java.lang.reflect.Array;
import java.lang.reflect.Constructor;
import java.lang.reflect.Method;
import java.util.Arrays;
import java.util.Comparator;

Expand All @@ -39,45 +37,37 @@
* @author Chris Hegarty <chris.hegarty@oracle.com>
*/
public class RecordSerializer<T> extends ImmutableSerializer<T> {
private static final MethodHandle MH_IS_RECORD;
private static final MethodHandle MH_GET_RECORD_COMPONENTS;
private static final MethodHandle MH_GET_NAME;
private static final MethodHandle MH_GET_TYPE;
private static final MethodHandles.Lookup LOOKUP;
private static final Method IS_RECORD;
private static final Method GET_RECORD_COMPONENTS;
private static final Method GET_NAME;
private static final Method GET_TYPE;

static {
MethodHandle MH_isRecord;
MethodHandle MH_getRecordComponents;
MethodHandle MH_getName;
MethodHandle MH_getType;
LOOKUP = MethodHandles.lookup();
Method isRecord;
Method getRecordComponents;
Method getName;
Method getType;

try {
// reflective machinery required to access the record components
// without a static dependency on Java SE 14 APIs
Class<?> c = Class.forName("java.lang.reflect.RecordComponent");
MH_isRecord = LOOKUP.findVirtual(Class.class, "isRecord", methodType(boolean.class));
MH_getRecordComponents = LOOKUP.findVirtual(Class.class, "getRecordComponents",
methodType(Array.newInstance(c, 0).getClass()))
.asType(methodType(Object[].class, Class.class));
MH_getName = LOOKUP.findVirtual(c, "getName", methodType(String.class))
.asType(methodType(String.class, Object.class));
MH_getType = LOOKUP.findVirtual(c, "getType", methodType(Class.class))
.asType(methodType(Class.class, Object.class));
isRecord = Class.class.getDeclaredMethod("isRecord");
getRecordComponents = Class.class.getMethod("getRecordComponents");
getName = c.getMethod("getName");
getType = c.getMethod("getType");
} catch (ClassNotFoundException | NoSuchMethodException e) {
// pre-Java-14
MH_isRecord = null;
MH_getRecordComponents = null;
MH_getName = null;
MH_getType = null;
} catch (IllegalAccessException unexpected) {
throw new AssertionError(unexpected);
isRecord = null;
getRecordComponents = null;
getName = null;
getType = null;
}

MH_IS_RECORD = MH_isRecord;
MH_GET_RECORD_COMPONENTS = MH_getRecordComponents;
MH_GET_NAME = MH_getName;
MH_GET_TYPE = MH_getType;
IS_RECORD = isRecord;
GET_RECORD_COMPONENTS = getRecordComponents;
GET_NAME = getName;
GET_TYPE = getType;
}

public RecordSerializer() {
Expand Down Expand Up @@ -142,7 +132,7 @@ public T read(Kryo kryo, Input input, Class<? extends T> type) {
/** Returns true if, and only if, the given class is a record class. */
private boolean isRecord(Class<?> type) {
try {
return (boolean) MH_IS_RECORD.invokeExact(type);
return (boolean) IS_RECORD.invoke(type);
} catch (Throwable t) {
throw new KryoException("Could not determine type (" + type + ")");
}
Expand Down Expand Up @@ -176,13 +166,13 @@ final static class RecordComponent {
private static <T> RecordComponent[] recordComponents(Class<T> type,
Comparator<RecordComponent> comparator) {
try {
Object[] rawComponents = (Object[]) MH_GET_RECORD_COMPONENTS.invokeExact(type);
Object[] rawComponents = (Object[]) GET_RECORD_COMPONENTS.invoke(type);
RecordComponent[] recordComponents = new RecordComponent[rawComponents.length];
for (int i = 0; i < rawComponents.length; i++) {
final Object comp = rawComponents[i];
recordComponents[i] = new RecordComponent(
(String) MH_GET_NAME.invokeExact(comp),
(Class<?>) MH_GET_TYPE.invokeExact(comp), i);
(String) GET_NAME.invoke(comp),
(Class<?>) GET_TYPE.invoke(comp), i);
}
if (comparator != null) Arrays.sort(recordComponents, comparator);
return recordComponents;
Expand All @@ -197,10 +187,8 @@ private static <T> RecordComponent[] recordComponents(Class<T> type,
private static Object componentValue(Object recordObject,
RecordComponent recordComponent) {
try {
MethodHandle MH_get = LOOKUP.findVirtual(recordObject.getClass(),
recordComponent.name(),
methodType(recordComponent.type()));
return (Object) MH_get.invoke(recordObject);
Method get = recordObject.getClass().getDeclaredMethod(recordComponent.name());
return get.invoke(recordObject);
} catch (Throwable t) {
KryoException ex = new KryoException(t);
ex.addTrace("Could not retrieve record components ("
Expand All @@ -220,10 +208,8 @@ private static <T> T invokeCanonicalConstructor(Class<T> recordType,
Class<?>[] paramTypes = Arrays.stream(recordComponents)
.map(RecordComponent::type)
.toArray(Class<?>[]::new);
MethodHandle MH_canonicalConstructor =
LOOKUP.findConstructor(recordType, methodType(void.class, paramTypes))
.asType(methodType(Object.class, paramTypes));
return (T)MH_canonicalConstructor.invokeWithArguments(args);
Constructor<T> canonicalConstructor = recordType.getConstructor(paramTypes);
return canonicalConstructor.newInstance(args);
} catch (Throwable t) {
KryoException ex = new KryoException(t);
ex.addTrace("Could not construct type (" + recordType.getName() + ")");
Expand Down
2 changes: 1 addition & 1 deletion test-jdk14/com/esotericsoftware/kryo/serializers/RecordSerializerTest.java
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Original file line number Diff line number Diff line change
Expand Up @@ -258,7 +258,7 @@ static <T extends Throwable> T expectThrows(Class<T> throwableClass, Runnable ta
task.run();
throw new AssertionError("Exception not thrown");
} catch (KryoException ce) {
Throwable cause = ce.getCause();
Throwable cause = ce.getCause().getCause();
if (!throwableClass.isInstance(cause)) {
throw new RuntimeException("expected: " + throwableClass + ", actual: " + cause);
}
Expand Down

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