/*

 * Copyright (c) 2012, 2014, 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.

 *

 * 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

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 *

 */

package sun.hotspot;

import java.lang.reflect.Executable;

import java.util.Arrays;

import java.util.List;

import java.util.function.Function;

import java.util.stream.Stream;

import java.security.BasicPermission;

import sun.hotspot.parser.DiagnosticCommand;

public class WhiteBox {

  @SuppressWarnings("serial")

  public static class WhiteBoxPermission extends BasicPermission {

    public WhiteBoxPermission(String s) {

      super(s);

    }

  }

  private WhiteBox() {}

  private static final WhiteBox instance = new WhiteBox();

  private static native void registerNatives();

  /**

   * Returns the singleton WhiteBox instance.

   *

   * The returned WhiteBox object should be carefully guarded

   * by the caller, since it can be used to read and write data

   * at arbitrary memory addresses. It must never be passed to

   * untrusted code.

   */

  public synchronized static WhiteBox getWhiteBox() {

    SecurityManager sm = System.getSecurityManager();

    if (sm != null) {

      sm.checkPermission(new WhiteBoxPermission("getInstance"));

    }

    return instance;

  }

  static {

    registerNatives();

  }

  // Get the maximum heap size supporting COOPs

  public native long getCompressedOopsMaxHeapSize();

  // Arguments

  public native void printHeapSizes();

  // Memory

  public native long getObjectAddress(Object o);

  public native int  getHeapOopSize();

  public native boolean isObjectInOldGen(Object o);

  public native long getObjectSize(Object o);

  // Runtime

  // Make sure class name is in the correct format

  public boolean isClassAlive(String name) {

    return isClassAlive0(name.replace('.', '/'));

  }

  private native boolean isClassAlive0(String name);

  // G1

  public native boolean g1InConcurrentMark();

  public native boolean g1IsHumongous(Object o);

  public native long    g1NumFreeRegions();

  public native int     g1RegionSize();

  public native Object[]    parseCommandLine(String commandline, DiagnosticCommand[] args);

  // NMT

  public native long NMTMalloc(long size);

  public native void NMTFree(long mem);

  public native long NMTReserveMemory(long size);

  public native void NMTCommitMemory(long addr, long size);

  public native void NMTUncommitMemory(long addr, long size);

  public native void NMTReleaseMemory(long addr, long size);

  public native long NMTMallocWithPseudoStack(long size, int index);

  public native boolean NMTIsDetailSupported();

  public native boolean NMTChangeTrackingLevel();

  // Compiler

  public native void    deoptimizeAll();

  public        boolean isMethodCompiled(Executable method) {

    return isMethodCompiled(method, false /*not osr*/);

  }

  public native boolean isMethodCompiled(Executable method, boolean isOsr);

  public        boolean isMethodCompilable(Executable method) {

    return isMethodCompilable(method, -1 /*any*/);

  }

  public        boolean isMethodCompilable(Executable method, int compLevel) {

    return isMethodCompilable(method, compLevel, false /*not osr*/);

  }

  public native boolean isMethodCompilable(Executable method, int compLevel, boolean isOsr);

  public native boolean isMethodQueuedForCompilation(Executable method);

  public        int     deoptimizeMethod(Executable method) {

    return deoptimizeMethod(method, false /*not osr*/);

  }

  public native int     deoptimizeMethod(Executable method, boolean isOsr);

  public        void    makeMethodNotCompilable(Executable method) {

    makeMethodNotCompilable(method, -1 /*any*/);

  }

  public        void    makeMethodNotCompilable(Executable method, int compLevel) {

    makeMethodNotCompilable(method, compLevel, false /*not osr*/);

  }

  public native void    makeMethodNotCompilable(Executable method, int compLevel, boolean isOsr);

  public        int     getMethodCompilationLevel(Executable method) {

    return getMethodCompilationLevel(method, false /*not ost*/);

  }

  public native int     getMethodCompilationLevel(Executable method, boolean isOsr);

  public native boolean testSetDontInlineMethod(Executable method, boolean value);

  public        int     getCompileQueuesSize() {

    return getCompileQueueSize(-1 /*any*/);

  }

  public native int     getCompileQueueSize(int compLevel);

  public native boolean testSetForceInlineMethod(Executable method, boolean value);

  public        boolean enqueueMethodForCompilation(Executable method, int compLevel) {

    return enqueueMethodForCompilation(method, compLevel, -1 /*InvocationEntryBci*/);

  }

  public native boolean enqueueMethodForCompilation(Executable method, int compLevel, int entry_bci);

  public native void    clearMethodState(Executable method);

  public native int     getMethodEntryBci(Executable method);

  public native Object[] getNMethod(Executable method, boolean isOsr);

  // Intered strings

  public native boolean isInStringTable(String str);

  // Memory

  public native void readReservedMemory();

  public native long allocateMetaspace(ClassLoader classLoader, long size);

  public native void freeMetaspace(ClassLoader classLoader, long addr, long size);

  public native long incMetaspaceCapacityUntilGC(long increment);

  public native long metaspaceCapacityUntilGC();

  // force Young GC

  public native void youngGC();

  // force Full GC

  public native void fullGC();

  // Tests on ReservedSpace/VirtualSpace classes

  public native int stressVirtualSpaceResize(long reservedSpaceSize, long magnitude, long iterations);

  public native void runMemoryUnitTests();

  public native void readFromNoaccessArea();

  public native long getThreadStackSize();

  public native long getThreadRemainingStackSize();

  // CPU features

  public native String getCPUFeatures();

  // Native extensions

  public native long getHeapUsageForContext(int context);

  public native long getHeapRegionCountForContext(int context);

  public native int getContextForObject(Object obj);

  public native void printRegionInfo(int context);

  // VM flags

  public native boolean isConstantVMFlag(String name);

  public native boolean isLockedVMFlag(String name);

  public native void    setBooleanVMFlag(String name, boolean value);

  public native void    setIntxVMFlag(String name, long value);

  public native void    setUintxVMFlag(String name, long value);

  public native void    setUint64VMFlag(String name, long value);

  public native void    setSizeTVMFlag(String name, long value);

  public native void    setStringVMFlag(String name, String value);

  public native void    setDoubleVMFlag(String name, double value);

  public native Boolean getBooleanVMFlag(String name);

  public native Long    getIntxVMFlag(String name);

  public native Long    getUintxVMFlag(String name);

  public native Long    getUint64VMFlag(String name);

  public native Long    getSizeTVMFlag(String name);

  public native String  getStringVMFlag(String name);

  public native Double  getDoubleVMFlag(String name);

  private final List<Function<String,Object>> flagsGetters = Arrays.asList(

    this::getBooleanVMFlag, this::getIntxVMFlag, this::getUintxVMFlag,

    this::getUint64VMFlag, this::getSizeTVMFlag, this::getStringVMFlag,

    this::getDoubleVMFlag);

  public Object getVMFlag(String name) {

    return flagsGetters.stream()

                       .map(f -> f.apply(name))

                       .filter(x -> x != null)

                       .findAny()

                       .orElse(null);

  }

}