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/*
* 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 io.trino.sql.gen;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Maps;
import io.airlift.bytecode.BytecodeBlock;
import io.airlift.bytecode.ClassDefinition;
import io.airlift.bytecode.DynamicClassLoader;
import io.airlift.bytecode.MethodDefinition;
import io.airlift.bytecode.Parameter;
import io.airlift.bytecode.Variable;
import io.trino.util.Reflection;
import java.lang.invoke.MethodHandle;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.function.Function;
import static io.airlift.bytecode.Access.FINAL;
import static io.airlift.bytecode.Access.PUBLIC;
import static io.airlift.bytecode.Access.STATIC;
import static io.airlift.bytecode.Access.a;
import static io.airlift.bytecode.Parameter.arg;
import static io.airlift.bytecode.ParameterizedType.type;
import static io.airlift.bytecode.expression.BytecodeExpressions.constantInt;
import static io.airlift.bytecode.expression.BytecodeExpressions.constantString;
import static io.airlift.bytecode.expression.BytecodeExpressions.invokeStatic;
import static io.trino.spi.StandardErrorCode.NOT_SUPPORTED;
import static io.trino.sql.gen.BytecodeUtils.loadConstant;
import static io.trino.util.CompilerUtils.defineClass;
import static io.trino.util.CompilerUtils.makeClassName;
import static io.trino.util.Failures.checkCondition;
public final class VarArgsToMapAdapterGenerator
{
private VarArgsToMapAdapterGenerator() {}
/**
* Generate byte code that
*
*
takes a specified number of variables as arguments (types of the arguments are provided in {@code javaTypes})
*
put the variables in a map (keys of the map are provided in {@code names})
*
invoke the provided {@code function} with the map
*
return with the result of the function call (type must match {@code returnType})
*
*/
public static MethodHandle generateVarArgsToMapAdapter(Class returnType, List> javaTypes, List names, Function, Object> function)
{
checkCondition(javaTypes.size() <= 254, NOT_SUPPORTED, "Too many arguments for vararg function");
CallSiteBinder callSiteBinder = new CallSiteBinder();
ClassDefinition classDefinition = new ClassDefinition(a(PUBLIC, FINAL), makeClassName("VarArgsToMapAdapter"), type(Object.class));
ImmutableList.Builder parameterListBuilder = ImmutableList.builder();
for (int i = 0; i < javaTypes.size(); i++) {
Class javaType = javaTypes.get(i);
parameterListBuilder.add(arg("input_" + i, javaType));
}
ImmutableList parameterList = parameterListBuilder.build();
MethodDefinition methodDefinition = classDefinition.declareMethod(a(PUBLIC, STATIC), "varArgsToMap", type(returnType), parameterList);
BytecodeBlock body = methodDefinition.getBody();
// ImmutableMap.Builder cannot be used here because it doesn't allow nulls.
Variable map = methodDefinition.getScope().declareVariable(
"map",
methodDefinition.getBody(),
invokeStatic(Maps.class, "newHashMapWithExpectedSize", HashMap.class, constantInt(javaTypes.size())));
for (int i = 0; i < javaTypes.size(); i++) {
body.append(map.invoke("put", Object.class, constantString(names.get(i)).cast(Object.class), parameterList.get(i).cast(Object.class)));
}
body.append(
loadConstant(callSiteBinder, function, Function.class)
.invoke("apply", Object.class, map.cast(Object.class))
.cast(returnType)
.ret());
Class generatedClass = defineClass(classDefinition, Object.class, callSiteBinder.getBindings(), new DynamicClassLoader(VarArgsToMapAdapterGenerator.class.getClassLoader()));
return Reflection.methodHandle(generatedClass, "varArgsToMap", javaTypes.toArray(new Class[javaTypes.size()]));
}
}
