MethodHandleUtil.java
/*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.facebook.presto.common.block;
import com.facebook.presto.common.GenericInternalException;
import com.facebook.presto.common.type.Type;
import io.airlift.slice.Slice;
import java.lang.invoke.MethodHandle;
import java.lang.invoke.MethodHandles;
import java.lang.invoke.MethodType;
import static java.lang.String.format;
import static java.lang.invoke.MethodType.methodType;
public final class MethodHandleUtil
{
private static final MethodHandle GET_LONG = methodHandle(Type.class, "getLong", Block.class, int.class);
private static final MethodHandle GET_DOUBLE = methodHandle(Type.class, "getDouble", Block.class, int.class);
private static final MethodHandle GET_BOOLEAN = methodHandle(Type.class, "getBoolean", Block.class, int.class);
private static final MethodHandle GET_SLICE = methodHandle(Type.class, "getSlice", Block.class, int.class);
private static final MethodHandle GET_BLOCK = methodHandle(Type.class, "getObject", Block.class, int.class).asType(methodType(Block.class, Type.class, Block.class, int.class));
private static final MethodHandle WRITE_LONG = methodHandle(Type.class, "writeLong", BlockBuilder.class, long.class);
private static final MethodHandle WRITE_DOUBLE = methodHandle(Type.class, "writeDouble", BlockBuilder.class, double.class);
private static final MethodHandle WRITE_BOOLEAN = methodHandle(Type.class, "writeBoolean", BlockBuilder.class, boolean.class);
private static final MethodHandle WRITE_SLICE = methodHandle(Type.class, "writeSlice", BlockBuilder.class, Slice.class);
private static final MethodHandle WRITE_BLOCK = methodHandle(Type.class, "writeObject", BlockBuilder.class, Object.class).asType(methodType(void.class, Type.class, BlockBuilder.class, Block.class));
private MethodHandleUtil()
{
}
/**
* @param f (U, S1, S2, ..., Sm)R
* @param g (T1, T2, ..., Tn)U
* @return (T1, T2, ..., Tn, S1, S2, ..., Sm)R
*/
public static MethodHandle compose(MethodHandle f, MethodHandle g)
{
if (f.type().parameterType(0) != g.type().returnType()) {
throw new IllegalArgumentException(format("f.parameter(0) != g.return(). f: %s g: %s", f.type(), g.type()));
}
// Semantics: f => f
// Type: (U, S1, S2, ..., Sn)R => (U, T1, T2, ..., Tm, S1, S2, ..., Sn)R
MethodHandle fUTS = MethodHandles.dropArguments(f, 1, g.type().parameterList());
// Semantics: f => fg
// Type: (U, T1, T2, ..., Tm, S1, S2, ..., Sn)R => (T1, T2, ..., Tm, S1, S2, ..., Sn)R
return MethodHandles.foldArguments(fUTS, g);
}
/**
* @param f (U, V)R
* @param g (S1, S2, ..., Sm)U
* @param h (T1, T2, ..., Tn)V
* @return (S1, S2, ..., Sm, T1, T2, ..., Tn)R
*/
public static MethodHandle compose(MethodHandle f, MethodHandle g, MethodHandle h)
{
if (f.type().parameterCount() != 2) {
throw new IllegalArgumentException(format("f.parameterCount != 2. f: %s", f.type()));
}
if (f.type().parameterType(0) != g.type().returnType()) {
throw new IllegalArgumentException(format("f.parameter(0) != g.return. f: %s g: %s", f.type(), g.type()));
}
if (f.type().parameterType(1) != h.type().returnType()) {
throw new IllegalArgumentException(format("f.parameter(0) != h.return. f: %s h: %s", f.type(), h.type()));
}
// (V, T1, T2, ..., Tn, U)R
MethodType typeVTU = f.type().dropParameterTypes(0, 1).appendParameterTypes(h.type().parameterList()).appendParameterTypes(f.type().parameterType(0));
// Semantics: f => f
// Type: (U, V)R => (V, T1, T2, ..., Tn, U)R
MethodHandle fVTU = MethodHandles.permuteArguments(f, typeVTU, h.type().parameterCount() + 1, 0);
// Semantics: f => fh
// Type: (V, T1, T2, ..., Tn, U)R => (T1, T2, ..., Tn, U)R
MethodHandle fhTU = MethodHandles.foldArguments(fVTU, h);
// reorder: [m+1, m+2, ..., m+n, 0]
int[] reorder = new int[fhTU.type().parameterCount()];
for (int i = 0; i < reorder.length - 1; i++) {
reorder[i] = i + 1 + g.type().parameterCount();
}
reorder[reorder.length - 1] = 0;
// (U, S1, S2, ..., Sm, T1, T2, ..., Tn)R
MethodType typeUST = f.type().dropParameterTypes(1, 2).appendParameterTypes(g.type().parameterList()).appendParameterTypes(h.type().parameterList());
// Semantics: f.h => f.h
// Type: (T1, T2, ..., Tn, U)R => (U, S1, S2, ..., Sm, T1, T2, ..., Tn)R
MethodHandle fhUST = MethodHandles.permuteArguments(fhTU, typeUST, reorder);
// Semantics: fh => fgh
// Type: (U, S1, S2, ..., Sm, T1, T2, ..., Tn)R => (S1, S2, ..., Sm, T1, T2, ..., Tn)R
return MethodHandles.foldArguments(fhUST, g);
}
/**
* Returns a MethodHandle corresponding to the specified method.
* <p>
* Warning: The way Oracle JVM implements producing MethodHandle for a method involves creating
* JNI global weak references. G1 processes such references serially. As a result, calling this
* method in a tight loop can create significant GC pressure and significantly increase
* application pause time.
*/
public static MethodHandle methodHandle(Class<?> clazz, String name, Class<?>... parameterTypes)
{
try {
return MethodHandles.lookup().unreflect(clazz.getMethod(name, parameterTypes));
}
catch (IllegalAccessException | NoSuchMethodException e) {
throw new GenericInternalException(e);
}
}
public static MethodHandle nativeValueGetter(Type type)
{
Class<?> javaType = type.getJavaType();
MethodHandle methodHandle;
if (javaType == long.class) {
methodHandle = GET_LONG;
}
else if (javaType == double.class) {
methodHandle = GET_DOUBLE;
}
else if (javaType == boolean.class) {
methodHandle = GET_BOOLEAN;
}
else if (javaType == Slice.class) {
methodHandle = GET_SLICE;
}
else if (javaType == Block.class) {
methodHandle = GET_BLOCK;
}
else {
throw new IllegalArgumentException("Unknown java type " + javaType + " from type " + type);
}
return methodHandle.bindTo(type);
}
public static MethodHandle nativeValueWriter(Type type)
{
Class<?> javaType = type.getJavaType();
MethodHandle methodHandle;
if (javaType == long.class) {
methodHandle = WRITE_LONG;
}
else if (javaType == double.class) {
methodHandle = WRITE_DOUBLE;
}
else if (javaType == boolean.class) {
methodHandle = WRITE_BOOLEAN;
}
else if (javaType == Slice.class) {
methodHandle = WRITE_SLICE;
}
else if (javaType == Block.class) {
methodHandle = WRITE_BLOCK;
}
else {
throw new IllegalArgumentException("Unknown java type " + javaType + " from type " + type);
}
return methodHandle.bindTo(type);
}
}