/*
* 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.bytecode.BytecodeBlock;
import com.facebook.presto.bytecode.ClassDefinition;
import com.facebook.presto.bytecode.CompilerUtils;
import com.facebook.presto.bytecode.MethodDefinition;
import com.facebook.presto.bytecode.Parameter;
import com.facebook.presto.bytecode.Scope;
import com.facebook.presto.bytecode.Variable;
import com.facebook.presto.metadata.BoundVariables;
import com.facebook.presto.metadata.FunctionRegistry;
import com.facebook.presto.metadata.Signature;
import com.facebook.presto.metadata.SqlOperator;
import com.facebook.presto.spi.ConnectorSession;
import com.facebook.presto.spi.block.Block;
import com.facebook.presto.spi.type.Type;
import com.facebook.presto.spi.type.TypeManager;
import com.facebook.presto.sql.gen.ArrayGeneratorUtils;
import com.facebook.presto.sql.gen.ArrayMapBytecodeExpression;
import com.facebook.presto.sql.gen.CachedInstanceBinder;
import com.facebook.presto.sql.gen.CallSiteBinder;
import com.google.common.base.Joiner;
import com.google.common.collect.ImmutableList;
import java.lang.invoke.MethodHandle;
import static com.facebook.presto.bytecode.Access.FINAL;
import static com.facebook.presto.bytecode.Access.PUBLIC;
import static com.facebook.presto.bytecode.Access.STATIC;
import static com.facebook.presto.bytecode.Access.a;
import static com.facebook.presto.bytecode.CompilerUtils.defineClass;
import static com.facebook.presto.bytecode.Parameter.arg;
import static com.facebook.presto.bytecode.ParameterizedType.type;
import static com.facebook.presto.bytecode.expression.BytecodeExpressions.constantBoolean;
import static com.facebook.presto.metadata.Signature.internalOperator;
import static com.facebook.presto.metadata.Signature.typeVariable;
import static com.facebook.presto.spi.function.OperatorType.CAST;
import static com.facebook.presto.spi.type.TypeSignature.parseTypeSignature;
import static com.facebook.presto.util.Reflection.methodHandle;
import static com.google.common.base.Preconditions.checkArgument;
public class ArrayToArrayCast
extends SqlOperator
{
public static final ArrayToArrayCast ARRAY_TO_ARRAY_CAST = new ArrayToArrayCast();
private ArrayToArrayCast()
{
super(CAST,
ImmutableList.of(typeVariable("F"), typeVariable("T")),
ImmutableList.of(),
parseTypeSignature("array(T)"),
ImmutableList.of(parseTypeSignature("array(F)")));
}
@Override
public ScalarFunctionImplementation specialize(BoundVariables boundVariables, int arity, TypeManager typeManager, FunctionRegistry functionRegistry)
{
checkArgument(arity == 1, "Expected arity to be 1");
Type fromType = boundVariables.getTypeVariable("F");
Type toType = boundVariables.getTypeVariable("T");
Signature signature = internalOperator(CAST.name(), toType.getTypeSignature(), ImmutableList.of(fromType.getTypeSignature()));
ScalarFunctionImplementation function = functionRegistry.getScalarFunctionImplementation(signature);
Class<?> castOperatorClass = generateArrayCast(typeManager, signature, function);
MethodHandle methodHandle = methodHandle(castOperatorClass, "castArray", ConnectorSession.class, Block.class);
return new ScalarFunctionImplementation(false, ImmutableList.of(false), methodHandle, isDeterministic());
}
private static Class<?> generateArrayCast(TypeManager typeManager, Signature elementCastSignature, ScalarFunctionImplementation elementCast)
{
CallSiteBinder binder = new CallSiteBinder();
ClassDefinition definition = new ClassDefinition(
a(PUBLIC, FINAL),
CompilerUtils.makeClassName(Joiner.on("$").join("ArrayCast", elementCastSignature.getArgumentTypes().get(0), elementCastSignature.getReturnType())),
type(Object.class));
Parameter session = arg("session", ConnectorSession.class);
Parameter value = arg("value", Block.class);
MethodDefinition method = definition.declareMethod(
a(PUBLIC, STATIC),
"castArray",
type(Block.class),
session,
value);
Scope scope = method.getScope();
BytecodeBlock body = method.getBody();
Variable wasNull = scope.declareVariable(boolean.class, "wasNull");
body.append(wasNull.set(constantBoolean(false)));
// cast map elements
Type fromElementType = typeManager.getType(elementCastSignature.getArgumentTypes().get(0));
Type toElementType = typeManager.getType(elementCastSignature.getReturnType());
CachedInstanceBinder cachedInstanceBinder = new CachedInstanceBinder(definition, binder);
ArrayMapBytecodeExpression newArray = ArrayGeneratorUtils.map(scope, cachedInstanceBinder, fromElementType, toElementType, value, elementCastSignature.getName(), elementCast);
// return the block
body.append(newArray.ret());
MethodDefinition constructorDefinition = definition.declareConstructor(a(PUBLIC));
BytecodeBlock constructorBody = constructorDefinition.getBody();
Variable thisVariable = constructorDefinition.getThis();
constructorBody.comment("super();")
.append(thisVariable)
.invokeConstructor(Object.class);
cachedInstanceBinder.generateInitializations(thisVariable, constructorBody);
constructorBody.ret();
return defineClass(definition, Object.class, binder.getBindings(), ArrayToArrayCast.class.getClassLoader());
}
}