/*

 * 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 com.sun.tools.jdi;

import com.sun.jdi.*;

import com.sun.jdi.connect.spi.Connection;

import com.sun.jdi.request.EventRequestManager;

import com.sun.jdi.request.EventRequest;

import com.sun.jdi.request.BreakpointRequest;

import com.sun.jdi.event.EventQueue;

import java.util.*;

import java.text.MessageFormat;

import java.lang.ref.ReferenceQueue;

import java.lang.ref.Reference;

import java.lang.ref.SoftReference;

import java.lang.ref.WeakReference;

class VirtualMachineImpl extends MirrorImpl

             implements PathSearchingVirtualMachine, ThreadListener {

    // VM Level exported variables, these

    // are unique to a given vm

    public final int sizeofFieldRef;

    public final int sizeofMethodRef;

    public final int sizeofObjectRef;

    public final int sizeofClassRef;

    public final int sizeofFrameRef;

    final int sequenceNumber;

    private final TargetVM target;

    private final EventQueueImpl eventQueue;

    private final EventRequestManagerImpl internalEventRequestManager;

    private final EventRequestManagerImpl eventRequestManager;

    final VirtualMachineManagerImpl vmManager;

    private final ThreadGroup threadGroupForJDI;

    // Allow direct access to this field so that that tracing code slows down

    // JDI as little as possible when not enabled.

    int traceFlags = TRACE_NONE;

    static int TRACE_RAW_SENDS     = 0x01000000;

    static int TRACE_RAW_RECEIVES  = 0x02000000;

    boolean traceReceives = false;   // pre-compute because of frequency

    // ReferenceType access - updated with class prepare and unload events

    // Protected by "synchronized(this)". "retrievedAllTypes" may be

    // tested unsynchronized (since once true, it stays true), but must

    // be set synchronously

    private Map<Long, ReferenceType> typesByID;

    private TreeSet<ReferenceType> typesBySignature;

    private boolean retrievedAllTypes = false;

    // For other languages support

    private String defaultStratum = null;

    // ObjectReference cache

    // "objectsByID" protected by "synchronized(this)".

    private final Map<Long, SoftObjectReference> objectsByID = new HashMap<Long, SoftObjectReference>();

    private final ReferenceQueue<ObjectReferenceImpl> referenceQueue = new ReferenceQueue<ObjectReferenceImpl>();

    static private final int DISPOSE_THRESHOLD = 50;

    private final List<SoftObjectReference> batchedDisposeRequests =

            Collections.synchronizedList(new ArrayList<SoftObjectReference>(DISPOSE_THRESHOLD + 10));

    // These are cached once for the life of the VM

    private JDWP.VirtualMachine.Version versionInfo;

    private JDWP.VirtualMachine.ClassPaths pathInfo;

    private JDWP.VirtualMachine.Capabilities capabilities = null;

    private JDWP.VirtualMachine.CapabilitiesNew capabilitiesNew = null;

    // Per-vm singletons for primitive types and for void.

    // singleton-ness protected by "synchronized(this)".

    private BooleanType theBooleanType;

    private ByteType    theByteType;

    private CharType    theCharType;

    private ShortType   theShortType;

    private IntegerType theIntegerType;

    private LongType    theLongType;

    private FloatType   theFloatType;

    private DoubleType  theDoubleType;

    private VoidType    theVoidType;

    private VoidValue voidVal;

    // Launched debuggee process

    private Process process;

    // coordinates state changes and corresponding listener notifications

    private VMState state = new VMState(this);

    private Object initMonitor = new Object();

    private boolean initComplete = false;

    private boolean shutdown = false;

    private void notifyInitCompletion() {

        synchronized(initMonitor) {

            initComplete = true;

            initMonitor.notifyAll();

        }

    }

    void waitInitCompletion() {

        synchronized(initMonitor) {

            while (!initComplete) {

                try {

                    initMonitor.wait();

                } catch (InterruptedException e) {

                    // ignore

                }

            }

        }

    }

    VMState state() {

        return state;

    }

    /*

     * ThreadListener implementation

     */

    public boolean threadResumable(ThreadAction action) {

        /*

         * If any thread is resumed, the VM is considered not suspended.

         * Just one thread is being resumed so pass it to thaw.

         */

        state.thaw(action.thread());

        return true;

    }

    VirtualMachineImpl(VirtualMachineManager manager,

                       Connection connection, Process process,

                       int sequenceNumber) {

        super(null);  // Can't use super(this)

        vm = this;

        this.vmManager = (VirtualMachineManagerImpl)manager;

        this.process = process;

        this.sequenceNumber = sequenceNumber;

        /* Create ThreadGroup to be used by all threads servicing

         * this VM.

         */

        threadGroupForJDI = new ThreadGroup(vmManager.mainGroupForJDI(),

                                            "JDI [" +

                                            this.hashCode() + "]");

        /*

         * Set up a thread to communicate with the target VM over

         * the specified transport.

         */

        target = new TargetVM(this, connection);

        /*

         * Set up a thread to handle events processed internally

         * the JDI implementation.

         */

        EventQueueImpl internalEventQueue = new EventQueueImpl(this, target);

        new InternalEventHandler(this, internalEventQueue);

        /*

         * Initialize client access to event setting and handling

         */

        eventQueue = new EventQueueImpl(this, target);

        eventRequestManager = new EventRequestManagerImpl(this);

        target.start();

        /*

         * Many ids are variably sized, depending on target VM.

         * Find out the sizes right away.

         */

        JDWP.VirtualMachine.IDSizes idSizes;

        try {

            idSizes = JDWP.VirtualMachine.IDSizes.process(vm);

        } catch (JDWPException exc) {

            throw exc.toJDIException();

        }

        sizeofFieldRef  = idSizes.fieldIDSize;

        sizeofMethodRef = idSizes.methodIDSize;

        sizeofObjectRef = idSizes.objectIDSize;

        sizeofClassRef = idSizes.referenceTypeIDSize;

        sizeofFrameRef  = idSizes.frameIDSize;

        /**

         * Set up requests needed by internal event handler.

         * Make sure they are distinguished by creating them with

         * an internal event request manager.

         *

         * Warning: create events only with SUSPEND_NONE policy.

         * In the current implementation other policies will not

         * be handled correctly when the event comes in. (notfiySuspend()

         * will not be properly called, and if the event is combined

         * with external events in the same set, suspend policy is not

         * correctly determined for the internal vs. external event sets)

         */

        internalEventRequestManager = new EventRequestManagerImpl(this);

        EventRequest er = internalEventRequestManager.createClassPrepareRequest();

        er.setSuspendPolicy(EventRequest.SUSPEND_NONE);

        er.enable();

        er = internalEventRequestManager.createClassUnloadRequest();

        er.setSuspendPolicy(EventRequest.SUSPEND_NONE);

        er.enable();

        /*

         * Tell other threads, notably TargetVM, that initialization

         * is complete.

         */

        notifyInitCompletion();

    }

    EventRequestManagerImpl getInternalEventRequestManager() {

        return internalEventRequestManager;

    }

    void validateVM() {

        /*

         * We no longer need to do this.  The spec now says

         * that a VMDisconnected _may_ be thrown in these

         * cases, not that it _will_ be thrown.

         * So, to simplify things we will just let the

         * caller's of this method proceed with their business.

         * If the debuggee is disconnected, either because it

         * crashed or finished or something, or because the

         * debugger called exit() or dispose(), then if

         * we end up trying to communicate with the debuggee,

         * code in TargetVM will throw a VMDisconnectedException.

         * This means that if we can satisfy a request without

         * talking to the debuggee, (eg, with cached data) then

         * VMDisconnectedException will _not_ be thrown.

         * if (shutdown) {

         *    throw new VMDisconnectedException();

         * }

         */

    }

    public boolean equals(Object obj) {

        return this == obj;

    }

    public int hashCode() {

        return System.identityHashCode(this);

    }

    public List<ReferenceType> classesByName(String className) {

        validateVM();

        String signature = JNITypeParser.typeNameToSignature(className);

        List<ReferenceType> list;

        if (retrievedAllTypes) {

           list = findReferenceTypes(signature);

        } else {

           list = retrieveClassesBySignature(signature);

        }

        return Collections.unmodifiableList(list);

    }

    public List<ReferenceType> allClasses() {

        validateVM();

        if (!retrievedAllTypes) {

            retrieveAllClasses();

        }

        ArrayList<ReferenceType> a;

        synchronized (this) {

            a = new ArrayList<ReferenceType>(typesBySignature);

        }

        return Collections.unmodifiableList(a);

    }

    public void

        redefineClasses(Map<? extends ReferenceType,byte[]> classToBytes)

    {

        int cnt = classToBytes.size();

        JDWP.VirtualMachine.RedefineClasses.ClassDef[] defs =

            new JDWP.VirtualMachine.RedefineClasses.ClassDef[cnt];

        validateVM();

        if (!canRedefineClasses()) {

            throw new UnsupportedOperationException();

        }

        Iterator<?> it = classToBytes.entrySet().iterator();

        for (int i = 0; it.hasNext(); i++) {

            Map.Entry<?,?> entry = (Map.Entry)it.next();

            ReferenceTypeImpl refType = (ReferenceTypeImpl)entry.getKey();

            validateMirror(refType);

            defs[i] = new JDWP.VirtualMachine.RedefineClasses

                       .ClassDef(refType, (byte[])entry.getValue());

        }

        // flush caches and disable caching until the next suspend

        vm.state().thaw();

        try {

            JDWP.VirtualMachine.RedefineClasses.

                process(vm, defs);

        } catch (JDWPException exc) {

            switch (exc.errorCode()) {

            case JDWP.Error.INVALID_CLASS_FORMAT :

                throw new ClassFormatError(

                        "class not in class file format");

            case JDWP.Error.CIRCULAR_CLASS_DEFINITION :

                throw new ClassCircularityError(

       "circularity has been detected while initializing a class");

            case JDWP.Error.FAILS_VERIFICATION :

                throw new VerifyError(

   "verifier detected internal inconsistency or security problem");

            case JDWP.Error.UNSUPPORTED_VERSION :

                throw new UnsupportedClassVersionError(

                    "version numbers of class are not supported");

            case JDWP.Error.ADD_METHOD_NOT_IMPLEMENTED:

                throw new UnsupportedOperationException(

                              "add method not implemented");

            case JDWP.Error.SCHEMA_CHANGE_NOT_IMPLEMENTED :

                throw new UnsupportedOperationException(

                              "schema change not implemented");

            case JDWP.Error.HIERARCHY_CHANGE_NOT_IMPLEMENTED:

                throw new UnsupportedOperationException(

                              "hierarchy change not implemented");

            case JDWP.Error.DELETE_METHOD_NOT_IMPLEMENTED :

                throw new UnsupportedOperationException(

                              "delete method not implemented");

            case JDWP.Error.CLASS_MODIFIERS_CHANGE_NOT_IMPLEMENTED:

                throw new UnsupportedOperationException(

                       "changes to class modifiers not implemented");

            case JDWP.Error.METHOD_MODIFIERS_CHANGE_NOT_IMPLEMENTED :

                throw new UnsupportedOperationException(

                       "changes to method modifiers not implemented");

            case JDWP.Error.NAMES_DONT_MATCH :

                throw new NoClassDefFoundError(

                              "class names do not match");

            default:

                throw exc.toJDIException();

            }

        }

        // Delete any record of the breakpoints

        List<BreakpointRequest> toDelete = new ArrayList<BreakpointRequest>();

        EventRequestManager erm = eventRequestManager();

        it = erm.breakpointRequests().iterator();

        while (it.hasNext()) {

            BreakpointRequest req = (BreakpointRequest)it.next();

            if (classToBytes.containsKey(req.location().declaringType())) {

                toDelete.add(req);

            }

        }

        erm.deleteEventRequests(toDelete);

        // Invalidate any information cached for the classes just redefined.

        it = classToBytes.keySet().iterator();

        while (it.hasNext()) {

            ReferenceTypeImpl rti = (ReferenceTypeImpl)it.next();

            rti.noticeRedefineClass();

        }

    }

    public List<ThreadReference> allThreads() {

        validateVM();

        return state.allThreads();

    }

    public List<ThreadGroupReference> topLevelThreadGroups() {

        validateVM();

        return state.topLevelThreadGroups();

    }

    /*

     * Sends a command to the back end which is defined to do an

     * implicit vm-wide resume. The VM can no longer be considered

     * suspended, so certain cached data must be invalidated.

     */

    PacketStream sendResumingCommand(CommandSender sender) {

        return state.thawCommand(sender);

    }

    /*

     * The VM has been suspended. Additional caching can be done

     * as long as there are no pending resumes.

     */

    void notifySuspend() {

        state.freeze();

    }

    public void suspend() {

        validateVM();

        try {

            JDWP.VirtualMachine.Suspend.process(vm);

        } catch (JDWPException exc) {

            throw exc.toJDIException();

        }

        notifySuspend();

    }

    public void resume() {

        validateVM();

        CommandSender sender =

            new CommandSender() {

                public PacketStream send() {

                    return JDWP.VirtualMachine.Resume.enqueueCommand(vm);

                }

        };

        try {

            PacketStream stream = state.thawCommand(sender);

            JDWP.VirtualMachine.Resume.waitForReply(vm, stream);

        } catch (VMDisconnectedException exc) {

            /*

             * If the debugger makes a VMDeathRequest with SUSPEND_ALL,

             * then when it does an EventSet.resume after getting the

             * VMDeathEvent, the normal flow of events is that the

             * BE shuts down, but the waitForReply comes back ok.  In this

             * case, the run loop in TargetVM that is waiting for a packet

             * gets an EOF because the socket closes. It generates a

             * VMDisconnectedEvent and everyone is happy.

             * However, sometimes, the BE gets shutdown before this

             * waitForReply completes.  In this case, TargetVM.waitForReply

             * gets awakened with no reply and so gens a VMDisconnectedException

             * which is not what we want.  It might be possible to fix this

             * in the BE, but it is ok to just ignore the VMDisconnectedException

             * here.  This will allow the VMDisconnectedEvent to be generated

             * correctly.  And, if the debugger should happen to make another

             * request, it will get a VMDisconnectedException at that time.

             */

        } catch (JDWPException exc) {

            switch (exc.errorCode()) {

                case JDWP.Error.VM_DEAD:

                    return;

                default:

                    throw exc.toJDIException();

            }

        }

    }

    public EventQueue eventQueue() {

        /*

         * No VM validation here. We allow access to the event queue

         * after disconnection, so that there is access to the terminating

         * events.

         */

        return eventQueue;

    }

    public EventRequestManager eventRequestManager() {

        validateVM();

        return eventRequestManager;

    }

    EventRequestManagerImpl eventRequestManagerImpl() {

        return eventRequestManager;

    }

    public BooleanValue mirrorOf(boolean value) {

        validateVM();

        return new BooleanValueImpl(this,value);

    }

    public ByteValue mirrorOf(byte value) {

        validateVM();

        return new ByteValueImpl(this,value);

    }

    public CharValue mirrorOf(char value) {

        validateVM();

        return new CharValueImpl(this,value);

    }

    public ShortValue mirrorOf(short value) {

        validateVM();

        return new ShortValueImpl(this,value);

    }

    public IntegerValue mirrorOf(int value) {

        validateVM();

        return new IntegerValueImpl(this,value);

    }

    public LongValue mirrorOf(long value) {

        validateVM();

        return new LongValueImpl(this,value);

    }

    public FloatValue mirrorOf(float value) {

        validateVM();

        return new FloatValueImpl(this,value);

    }

    public DoubleValue mirrorOf(double value) {

        validateVM();

        return new DoubleValueImpl(this,value);

    }

    public StringReference mirrorOf(String value) {

        validateVM();

        try {

            return (StringReference)JDWP.VirtualMachine.CreateString.

                             process(vm, value).stringObject;

        } catch (JDWPException exc) {

            throw exc.toJDIException();

        }

    }

    public VoidValue mirrorOfVoid() {

        if (voidVal == null) {

            voidVal = new VoidValueImpl(this);

        }

        return voidVal;

    }