gradle-master/subprojects/workers/src/main/java/org/gradle/workers/internal/DefaultWorkerServer.java
/*
 * Copyright 2017 the original author or authors.
 *
 * 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 org.gradle.workers.internal;

import org.gradle.api.specs.Spec;
import org.gradle.internal.Cast;
import org.gradle.internal.instantiation.InstantiatorFactory;
import org.gradle.internal.isolated.IsolationScheme;
import org.gradle.internal.reflect.Instantiator;
import org.gradle.internal.service.ServiceLookup;
import org.gradle.internal.service.ServiceRegistry;
import org.gradle.workers.WorkAction;
import org.gradle.workers.WorkParameters;

import java.util.Collection;

public class DefaultWorkerServer implements Worker {
    private final ServiceRegistry internalServices;
    private final InstantiatorFactory instantiatorFactory;
    private final IsolationScheme<WorkAction<?>, WorkParameters> isolationScheme;
    private final Collection<? extends Class<?>> additionalWhitelistedServices;

    public DefaultWorkerServer(ServiceRegistry internalServices, InstantiatorFactory instantiatorFactory, IsolationScheme<WorkAction<?>, WorkParameters> isolationScheme, Collection<? extends Class<?>> additionalWhitelistedServices) {
        this.internalServices = internalServices;
        this.instantiatorFactory = instantiatorFactory;
        this.isolationScheme = isolationScheme;
        this.additionalWhitelistedServices = additionalWhitelistedServices;
    }

    @Override
    public DefaultWorkResult execute(SimpleActionExecutionSpec<?> spec) {
        try {
            Class<? extends WorkAction<?>> implementationClass = Cast.uncheckedCast(spec.getImplementationClass());
            // Exceptions to services available for injection
            Spec<Class<?>> whiteListPolicy;
            if (spec.isInternalServicesRequired()) {
                whiteListPolicy = element -> true;
            } else {
                whiteListPolicy = element -> false;
            }
            ServiceLookup instantiationServices = isolationScheme.servicesForImplementation(spec.getParameters(), internalServices, additionalWhitelistedServices, whiteListPolicy);
            Instantiator instantiator = instantiatorFactory.inject(instantiationServices);
            WorkAction<?> execution;
            if (ProvidesWorkResult.class.isAssignableFrom(implementationClass)) {
                execution = instantiator.newInstance(implementationClass, spec.getParameters(), instantiator);
            } else {
                execution = instantiator.newInstance(implementationClass);
            }
            execution.execute();
            if (execution instanceof ProvidesWorkResult) {
                return ((ProvidesWorkResult) execution).getWorkResult();
            } else {
                return DefaultWorkResult.SUCCESS;
            }
        } catch (Throwable t) {
            return new DefaultWorkResult(true, t);
        }
    }

    @Override
    public String toString() {
        return "DefaultWorkerServer{}";
    }
}
