/*
 * Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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 */

package jdk.internal.misc;

import java.util.Arrays;
import java.util.Map;
import java.util.Objects;
import java.util.stream.Stream;

import jdk.internal.access.JavaLangInvokeAccess;
import jdk.internal.access.SharedSecrets;

public class CDS {
    private static final boolean isDumpingClassList;
    private static final boolean isDumpingArchive;
    private static final boolean isSharingEnabled;
    static {
        isDumpingClassList = isDumpingClassList0();
        isDumpingArchive = isDumpingArchive0();
        isSharingEnabled = isSharingEnabled0();
    }

    
indicator for dumping class list.
/**
      * indicator for dumping class list.
      */
    public static boolean isDumpingClassList() {
        return isDumpingClassList;
    }

    
Is the VM writing to a (static or dynamic) CDS archive.
/**
      * Is the VM writing to a (static or dynamic) CDS archive.
      */
    public static boolean isDumpingArchive() {
        return isDumpingArchive;
    }

    
Is sharing enabled via the UseSharedSpaces flag.
/**
      * Is sharing enabled via the UseSharedSpaces flag.
      */
    public static boolean isSharingEnabled() {
        return isSharingEnabled;
    }
    private static native boolean isDumpingClassList0();
    private static native boolean isDumpingArchive0();
    private static native boolean isSharingEnabled0();
    private static native void logLambdaFormInvoker(String line);

    
Initialize archived static fields in the given Class using archived
values from CDS dump time. Also initialize the classes of objects in
the archived graph referenced by those fields.
Those static fields remain as uninitialized if there is no mapped CDS
java heap data or there is any error during initialization of the
object class in the archived graph.
/**
     * Initialize archived static fields in the given Class using archived
     * values from CDS dump time. Also initialize the classes of objects in
     * the archived graph referenced by those fields.
     *
     * Those static fields remain as uninitialized if there is no mapped CDS
     * java heap data or there is any error during initialization of the
     * object class in the archived graph.
     */
    public static native void initializeFromArchive(Class<?> c);

    
Ensure that the native representation of all archived java.lang.Module objects
are properly restored.
/**
     * Ensure that the native representation of all archived java.lang.Module objects
     * are properly restored.
     */
    public static native void defineArchivedModules(ClassLoader platformLoader, ClassLoader systemLoader);

    
Returns a predictable "random" seed derived from the VM's build ID and version,
to be used by java.util.ImmutableCollections to ensure that archived
ImmutableCollections are always sorted the same order for the same VM build.
/**
     * Returns a predictable "random" seed derived from the VM's build ID and version,
     * to be used by java.util.ImmutableCollections to ensure that archived
     * ImmutableCollections are always sorted the same order for the same VM build.
     */
    public static native long getRandomSeedForDumping();

    
log lambda form invoker holder, name and method type
/**
     * log lambda form invoker holder, name and method type
     */
    public static void traceLambdaFormInvoker(String prefix, String holder, String name, String type) {
        if (isDumpingClassList) {
            logLambdaFormInvoker(prefix + " " + holder + " " + name + " " + type);
        }
    }

    
log species
/**
      * log species
      */
    public static void traceSpeciesType(String prefix, String cn) {
        if (isDumpingClassList) {
            logLambdaFormInvoker(prefix + " " + cn);
        }
    }

    static final String DIRECT_HOLDER_CLASS_NAME  = "java.lang.invoke.DirectMethodHandle$Holder";
    static final String DELEGATING_HOLDER_CLASS_NAME = "java.lang.invoke.DelegatingMethodHandle$Holder";
    static final String BASIC_FORMS_HOLDER_CLASS_NAME = "java.lang.invoke.LambdaForm$Holder";
    static final String INVOKERS_HOLDER_CLASS_NAME = "java.lang.invoke.Invokers$Holder";

    private static boolean isValidHolderName(String name) {
        return name.equals(DIRECT_HOLDER_CLASS_NAME)      ||
               name.equals(DELEGATING_HOLDER_CLASS_NAME)  ||
               name.equals(BASIC_FORMS_HOLDER_CLASS_NAME) ||
               name.equals(INVOKERS_HOLDER_CLASS_NAME);
    }

    private static boolean isBasicTypeChar(char c) {
         return "LIJFDV".indexOf(c) >= 0;
    }

    private static boolean isValidMethodType(String type) {
        String[] typeParts = type.split("_");
        // check return type (second part)
        if (typeParts.length != 2 || typeParts[1].length() != 1
                || !isBasicTypeChar(typeParts[1].charAt(0))) {
            return false;
        }
        // first part
        if (!isBasicTypeChar(typeParts[0].charAt(0))) {
            return false;
        }
        for (int i = 1; i < typeParts[0].length(); i++) {
            char c = typeParts[0].charAt(i);
            if (!isBasicTypeChar(c)) {
                if (!(c >= '0' && c <= '9')) {
                    return false;
                }
            }
        }
        return true;
    }

    // Throw exception on invalid input
    private static void validateInputLines(String[] lines) {
        for (String s: lines) {
            if (!s.startsWith("[LF_RESOLVE]") && !s.startsWith("[SPECIES_RESOLVE]")) {
                throw new IllegalArgumentException("Wrong prefix: " + s);
            }

            String[] parts = s.split(" ");
            boolean isLF = s.startsWith("[LF_RESOLVE]");

            if (isLF) {
                if (parts.length != 4) {
                    throw new IllegalArgumentException("Incorrect number of items in the line: " + parts.length);
                }
                if (!isValidHolderName(parts[1])) {
                    throw new IllegalArgumentException("Invalid holder class name: " + parts[1]);
                }
                if (!isValidMethodType(parts[3])) {
                    throw new IllegalArgumentException("Invalid method type: " + parts[3]);
                }
            } else {
                if (parts.length != 2) {
                   throw new IllegalArgumentException("Incorrect number of items in the line: " + parts.length);
                }
           }
      }
    }

    
called from vm to generate MethodHandle holder classes
Params:
lines – in format of LF_RESOLVE or SPECIES_RESOLVE output
Returns:
Object[] if holder classes can be generated./**
     * called from vm to generate MethodHandle holder classes
     * @return {@code Object[]} if holder classes can be generated.
     * @param lines in format of LF_RESOLVE or SPECIES_RESOLVE output
     */
    private static Object[] generateLambdaFormHolderClasses(String[] lines) {
        Objects.requireNonNull(lines);
        validateInputLines(lines);
        Stream<String> lineStream = Arrays.stream(lines);
        Map<String, byte[]> result = SharedSecrets.getJavaLangInvokeAccess().generateHolderClasses(lineStream);
        int size = result.size();
        Object[] retArray = new Object[size * 2];
        int index = 0;
        for (Map.Entry<String, byte[]> entry : result.entrySet()) {
            retArray[index++] = entry.getKey();
            retArray[index++] = entry.getValue();
        };
        return retArray;
    }
}