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package com.oracle.graal.python.builtins.objects.cext.capi;

import static com.oracle.graal.python.builtins.objects.cext.capi.DynamicObjectNativeWrapper.GP_OBJECT;
import static com.oracle.graal.python.builtins.objects.cext.capi.NativeMember.OB_BASE;
import static com.oracle.graal.python.builtins.objects.cext.capi.NativeMember.OB_REFCNT;
import static com.oracle.graal.python.builtins.objects.cext.capi.NativeMember.OB_TYPE;

import com.oracle.graal.python.builtins.objects.cext.capi.CExtNodes.IsPointerNode;
import com.oracle.graal.python.builtins.objects.cext.capi.DynamicObjectNativeWrapper.PAsPointerNode;
import com.oracle.graal.python.builtins.objects.cext.capi.DynamicObjectNativeWrapper.ReadNativeMemberDispatchNode;
import com.oracle.graal.python.builtins.objects.cext.capi.DynamicObjectNativeWrapper.ToNativeNode;
import com.oracle.graal.python.builtins.objects.cext.capi.DynamicObjectNativeWrapper.WriteNativeMemberNode;
import com.oracle.graal.python.runtime.GilNode;
import com.oracle.graal.python.runtime.interop.InteropArray;
import com.oracle.truffle.api.CompilerDirectives;
import com.oracle.truffle.api.CompilerDirectives.CompilationFinal;
import com.oracle.truffle.api.dsl.Cached;
import com.oracle.truffle.api.dsl.Cached.Exclusive;
import com.oracle.truffle.api.dsl.Specialization;
import com.oracle.truffle.api.interop.InteropLibrary;
import com.oracle.truffle.api.interop.UnknownIdentifierException;
import com.oracle.truffle.api.interop.UnsupportedMessageException;
import com.oracle.truffle.api.interop.UnsupportedTypeException;
import com.oracle.truffle.api.library.CachedLibrary;
import com.oracle.truffle.api.library.ExportLibrary;
import com.oracle.truffle.api.library.ExportMessage;
import com.oracle.truffle.api.nodes.ExplodeLoop;
import com.oracle.truffle.llvm.spi.NativeTypeLibrary;

@ExportLibrary(InteropLibrary.class)
@ExportLibrary(value = NativeTypeLibrary.class, useForAOT = false)
public class TruffleObjectNativeWrapper extends PythonNativeWrapper {

    // every 'PyObject *' provides 'ob_base', 'ob_type', and 'ob_refcnt'
    @CompilationFinal(dimensions = 1) private static final String[] MEMBERS = {GP_OBJECT, OB_BASE.getMemberName(), OB_TYPE.getMemberName(), OB_REFCNT.getMemberName()};

    public TruffleObjectNativeWrapper(Object foreignObject) {
        super(foreignObject);
    }

    public static TruffleObjectNativeWrapper wrap(Object foreignObject) {
        assert !CApiGuards.isNativeWrapper(foreignObject) : "attempting to wrap a native wrapper";
        return new TruffleObjectNativeWrapper(foreignObject);
    }

    @ExplodeLoop
    private static int indexOf(String member) {
        for (int i = 0; i < MEMBERS.length; i++) {
            if (MEMBERS[i].equals(member)) {
                return i;
            }
        }
        return -1;
    }

    @ExportMessage
    boolean hasMembers() {
        return true;
    }

    @ExportMessage
    @ExplodeLoop
    boolean isMemberReadable(String member) {
        return indexOf(member) != -1;
    }

    @ExportMessage
    boolean isMemberModifiable(String member) {
        // we only allow to write to 'ob_refcnt'
        return OB_REFCNT.getMemberName().equals(member);
    }

    @ExportMessage
    boolean isMemberInsertable(@SuppressWarnings("unused") String member) {
        return false;
    }

    @ExportMessage
    Object getMembers(@SuppressWarnings("unused") boolean includeInternal) {
        return new InteropArray(MEMBERS);
    }

    @ExportMessage(name = "readMember")
    abstract static class ReadNode {

        @Specialization(guards = {"key == cachedObBase", "isObBase(cachedObBase)"}, limit = "1")
        static Object doObBaseCached(TruffleObjectNativeWrapper object, @SuppressWarnings("unused") String key,
                        @Cached("key") @SuppressWarnings("unused") String cachedObBase) {
            return object;
        }

        @Specialization
        static Object execute(TruffleObjectNativeWrapper object, String key,
                        @CachedLibrary("object") PythonNativeWrapperLibrary lib,
                        @Cached ReadNativeMemberDispatchNode readNativeMemberNode,
                        @Exclusive @Cached GilNode gil) throws UnsupportedMessageException, UnknownIdentifierException {
            boolean mustRelease = gil.acquire();
            try {
                Object delegate = lib.getDelegate(object);

                // special key for the debugger
                if (GP_OBJECT.equals(key)) {
                    return delegate;
                }
                return readNativeMemberNode.execute(delegate, object, key);
            } finally {
                gil.release(mustRelease);
            }
        }

        protected static boolean isObBase(String key) {
            return OB_BASE.getMemberName().equals(key);
        }
    }

    @ExportMessage
    void writeMember(String member, Object value,
                    @CachedLibrary("this") PythonNativeWrapperLibrary lib,
                    @Cached WriteNativeMemberNode writeNativeMemberNode,
                    @Exclusive @Cached GilNode gil) throws UnknownIdentifierException, UnsupportedMessageException, UnsupportedTypeException {
        boolean mustRelease = gil.acquire();
        try {
            if (OB_REFCNT.getMemberName().equals(member)) {
                Object delegate = lib.getDelegate(this);
                writeNativeMemberNode.execute(delegate, this, member, value);
            } else {
                CompilerDirectives.transferToInterpreter();
                if (indexOf(member) == -1) {
                    throw UnknownIdentifierException.create(member);
                }
                throw UnsupportedMessageException.create();
            }
        } finally {
            gil.release(mustRelease);
        }
    }

    @ExportMessage
    boolean isPointer(
                    @Cached IsPointerNode pIsPointerNode) {
        return pIsPointerNode.execute(this);
    }

    @ExportMessage
    long asPointer(
                    @Cached PAsPointerNode pAsPointerNode) {
        return pAsPointerNode.execute(this);
    }

    @ExportMessage
    void toNative(
                    @Cached ToNativeNode toNativeNode) {
        toNativeNode.execute(this);
    }

    @ExportMessage
    boolean hasNativeType() {
        return true;
    }

    @ExportMessage
    Object getNativeType(
                    @Cached PGetDynamicTypeNode getDynamicTypeNode) {
        return getDynamicTypeNode.execute(this);
    }
}
