/*
* 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.operator.scalar;
import com.facebook.presto.annotation.UsedByGeneratedCode;
import com.facebook.presto.metadata.BoundVariables;
import com.facebook.presto.metadata.FunctionKind;
import com.facebook.presto.metadata.FunctionRegistry;
import com.facebook.presto.metadata.Signature;
import com.facebook.presto.metadata.SqlScalarFunction;
import com.facebook.presto.spi.PrestoException;
import com.facebook.presto.spi.block.Block;
import com.facebook.presto.spi.function.OperatorType;
import com.facebook.presto.spi.type.BooleanType;
import com.facebook.presto.spi.type.Type;
import com.facebook.presto.spi.type.TypeManager;
import com.google.common.base.Throwables;
import com.google.common.collect.ImmutableList;
import com.google.common.primitives.Primitives;
import io.airlift.slice.Slice;
import java.lang.invoke.MethodHandle;
import static com.facebook.presto.metadata.Signature.internalOperator;
import static com.facebook.presto.metadata.Signature.typeVariable;
import static com.facebook.presto.spi.StandardErrorCode.GENERIC_INTERNAL_ERROR;
import static com.facebook.presto.spi.type.TypeSignature.parseTypeSignature;
import static com.facebook.presto.spi.type.TypeUtils.readNativeValue;
import static com.facebook.presto.util.Reflection.methodHandle;
public class MapElementAtFunction
extends SqlScalarFunction
{
public static final MapElementAtFunction MAP_ELEMENT_AT = new MapElementAtFunction();
private static final MethodHandle METHOD_HANDLE_BOOLEAN = methodHandle(MapElementAtFunction.class, "elementAt", MethodHandle.class, Type.class, Type.class, Block.class, boolean.class);
private static final MethodHandle METHOD_HANDLE_LONG = methodHandle(MapElementAtFunction.class, "elementAt", MethodHandle.class, Type.class, Type.class, Block.class, long.class);
private static final MethodHandle METHOD_HANDLE_DOUBLE = methodHandle(MapElementAtFunction.class, "elementAt", MethodHandle.class, Type.class, Type.class, Block.class, double.class);
private static final MethodHandle METHOD_HANDLE_SLICE = methodHandle(MapElementAtFunction.class, "elementAt", MethodHandle.class, Type.class, Type.class, Block.class, Slice.class);
private static final MethodHandle METHOD_HANDLE_OBJECT = methodHandle(MapElementAtFunction.class, "elementAt", MethodHandle.class, Type.class, Type.class, Block.class, Object.class);
protected MapElementAtFunction()
{
super(new Signature(
"element_at",
FunctionKind.SCALAR,
ImmutableList.of(typeVariable("K"), typeVariable("V")),
ImmutableList.of(),
parseTypeSignature("V"),
ImmutableList.of(parseTypeSignature("map(K,V)"), parseTypeSignature("K")),
false));
}
@Override
public boolean isHidden()
{
return false;
}
@Override
public boolean isDeterministic()
{
return true;
}
@Override
public String getDescription()
{
return "Get value for the given key, or null if it does not exist";
}
@Override
public ScalarFunctionImplementation specialize(BoundVariables boundVariables, int arity, TypeManager typeManager, FunctionRegistry functionRegistry)
{
Type keyType = boundVariables.getTypeVariable("K");
Type valueType = boundVariables.getTypeVariable("V");
MethodHandle keyEqualsMethod = functionRegistry.getScalarFunctionImplementation(internalOperator(OperatorType.EQUAL, BooleanType.BOOLEAN, ImmutableList.of(keyType, keyType))).getMethodHandle();
MethodHandle methodHandle;
if (keyType.getJavaType() == boolean.class) {
methodHandle = METHOD_HANDLE_BOOLEAN;
}
else if (keyType.getJavaType() == long.class) {
methodHandle = METHOD_HANDLE_LONG;
}
else if (keyType.getJavaType() == double.class) {
methodHandle = METHOD_HANDLE_DOUBLE;
}
else if (keyType.getJavaType() == Slice.class) {
methodHandle = METHOD_HANDLE_SLICE;
}
else {
methodHandle = METHOD_HANDLE_OBJECT;
}
methodHandle = methodHandle.bindTo(keyEqualsMethod).bindTo(keyType).bindTo(valueType);
// this casting is necessary because otherwise presto byte code generator will generate illegal byte code
if (valueType.getJavaType() == void.class) {
methodHandle = methodHandle.asType(methodHandle.type().changeReturnType(void.class));
}
else {
methodHandle = methodHandle.asType(methodHandle.type().changeReturnType(Primitives.wrap(valueType.getJavaType())));
}
return new ScalarFunctionImplementation(true, ImmutableList.of(false, false), methodHandle, isDeterministic());
}
@UsedByGeneratedCode
public static Object elementAt(MethodHandle keyEqualsMethod, Type keyType, Type valueType, Block map, boolean key)
{
for (int position = 0; position < map.getPositionCount(); position += 2) {
try {
if ((boolean) keyEqualsMethod.invokeExact(keyType.getBoolean(map, position), key)) {
return readNativeValue(valueType, map, position + 1); // position + 1: value position
}
}
catch (Throwable t) {
Throwables.propagateIfInstanceOf(t, Error.class);
Throwables.propagateIfInstanceOf(t, PrestoException.class);
throw new PrestoException(GENERIC_INTERNAL_ERROR, t);
}
}
return null;
}
@UsedByGeneratedCode
public static Object elementAt(MethodHandle keyEqualsMethod, Type keyType, Type valueType, Block map, long key)
{
for (int position = 0; position < map.getPositionCount(); position += 2) {
try {
if ((boolean) keyEqualsMethod.invokeExact(keyType.getLong(map, position), key)) {
return readNativeValue(valueType, map, position + 1); // position + 1: value position
}
}
catch (Throwable t) {
Throwables.propagateIfInstanceOf(t, Error.class);
Throwables.propagateIfInstanceOf(t, PrestoException.class);
throw new PrestoException(GENERIC_INTERNAL_ERROR, t);
}
}
return null;
}
@UsedByGeneratedCode
public static Object elementAt(MethodHandle keyEqualsMethod, Type keyType, Type valueType, Block map, double key)
{
for (int position = 0; position < map.getPositionCount(); position += 2) {
try {
if ((boolean) keyEqualsMethod.invokeExact(keyType.getDouble(map, position), key)) {
return readNativeValue(valueType, map, position + 1); // position + 1: value position
}
}
catch (Throwable t) {
Throwables.propagateIfInstanceOf(t, Error.class);
Throwables.propagateIfInstanceOf(t, PrestoException.class);
throw new PrestoException(GENERIC_INTERNAL_ERROR, t);
}
}
return null;
}
@UsedByGeneratedCode
public static Object elementAt(MethodHandle keyEqualsMethod, Type keyType, Type valueType, Block map, Slice key)
{
for (int position = 0; position < map.getPositionCount(); position += 2) {
try {
if ((boolean) keyEqualsMethod.invokeExact(keyType.getSlice(map, position), key)) {
return readNativeValue(valueType, map, position + 1); // position + 1: value position
}
}
catch (Throwable t) {
Throwables.propagateIfInstanceOf(t, Error.class);
Throwables.propagateIfInstanceOf(t, PrestoException.class);
throw new PrestoException(GENERIC_INTERNAL_ERROR, t);
}
}
return null;
}
@UsedByGeneratedCode
public static Object elementAt(MethodHandle keyEqualsMethod, Type keyType, Type valueType, Block map, Object key)
{
for (int position = 0; position < map.getPositionCount(); position += 2) {
try {
if ((boolean) keyEqualsMethod.invokeExact(keyType.getObject(map, position), key)) {
return readNativeValue(valueType, map, position + 1); // position + 1: value position
}
}
catch (Throwable t) {
Throwables.propagateIfInstanceOf(t, Error.class);
Throwables.propagateIfInstanceOf(t, PrestoException.class);
throw new PrestoException(GENERIC_INTERNAL_ERROR, t);
}
}
return null;
}
}