gradle-master/subprojects/launcher/src/main/java/org/gradle/launcher/daemon/client/DaemonGreeter.java
/*
 * Copyright 2018 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.launcher.daemon.client;

import com.google.common.base.Joiner;
import org.gradle.api.GradleException;
import org.gradle.api.internal.DocumentationRegistry;
import org.gradle.launcher.daemon.bootstrap.DaemonStartupCommunication;
import org.gradle.launcher.daemon.diagnostics.DaemonStartupInfo;
import org.gradle.launcher.daemon.logging.DaemonMessages;

import java.util.List;

public class DaemonGreeter {
    private final DocumentationRegistry documentationRegistry;

    public DaemonGreeter(DocumentationRegistry documentationRegistry) {
        this.documentationRegistry = documentationRegistry;
    }

    public DaemonStartupInfo parseDaemonOutput(String output, List<String> startupArgs) {
        DaemonStartupCommunication startupCommunication = new DaemonStartupCommunication();
        if (!startupCommunication.containsGreeting(output)) {
            throw new GradleException(prepareMessage(output, startupArgs));
        }
        String[] lines = output.split("\n");
        //Assuming that the diagnostics were printed out to the last line. It's not bullet-proof but seems to be doing fine.
        String lastLine = lines[lines.length - 1];
        return startupCommunication.readDiagnostics(lastLine);
    }

    private String prepareMessage(String output, List<String> startupArgs) {
        return DaemonMessages.UNABLE_TO_START_DAEMON +
            "\nThis problem might be caused by incorrect configuration of the daemon." +
            "\nFor example, an unrecognized jvm option is used." +
            documentationRegistry.getDocumentationRecommendationFor("details on the daemon", "gradle_daemon") +
            "\nProcess command line: " + Joiner.on(" ").join(startupArgs) +
            "\nPlease read the following process output to find out more:" +
            "\n-----------------------\n" +
            output;
    }
}
