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package com.oracle.graal.python.nodes.attributes;

import com.oracle.graal.python.PythonLanguage;
import com.oracle.graal.python.builtins.Python3Core;
import com.oracle.graal.python.builtins.PythonBuiltinClassType;
import com.oracle.graal.python.builtins.objects.PNone;
import com.oracle.graal.python.builtins.objects.cext.PythonAbstractNativeObject;
import com.oracle.graal.python.builtins.objects.cext.capi.CExtNodes;
import com.oracle.graal.python.builtins.objects.cext.capi.NativeMember;
import com.oracle.graal.python.builtins.objects.common.HashingStorageLibrary;
import com.oracle.graal.python.builtins.objects.dict.PDict;
import com.oracle.graal.python.builtins.objects.type.MroShape;
import com.oracle.graal.python.builtins.objects.type.MroShape.MroShapeLookupResult;
import com.oracle.graal.python.builtins.objects.type.PythonClass;
import com.oracle.graal.python.builtins.objects.type.TypeNodes;
import com.oracle.graal.python.builtins.objects.type.TypeNodes.GetMroStorageNode;
import com.oracle.graal.python.builtins.objects.type.TypeNodesFactory.IsSameTypeNodeGen;
import com.oracle.graal.python.nodes.PNodeWithContext;
import com.oracle.graal.python.nodes.object.GetDictIfExistsNode;
import com.oracle.graal.python.runtime.PythonContext;
import com.oracle.graal.python.runtime.PythonOptions;
import com.oracle.graal.python.runtime.sequence.storage.MroSequenceStorage;
import com.oracle.truffle.api.Assumption;
import com.oracle.truffle.api.CompilerAsserts;
import com.oracle.truffle.api.CompilerDirectives;
import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
import com.oracle.truffle.api.dsl.Bind;
import com.oracle.truffle.api.dsl.Cached;
import com.oracle.truffle.api.dsl.GenerateUncached;
import com.oracle.truffle.api.dsl.ImportStatic;
import com.oracle.truffle.api.dsl.ReportPolymorphism.Megamorphic;
import com.oracle.truffle.api.dsl.Specialization;
import com.oracle.truffle.api.nodes.ExplodeLoop;

@ImportStatic(PythonOptions.class)
public abstract class LookupAttributeInMRONode extends LookupInMROBaseNode {
    @GenerateUncached
    public abstract static class Dynamic extends PNodeWithContext {
        public abstract Object execute(Object klass, Object key);

        protected static boolean compareStrings(String key, String cachedKey) {
            return cachedKey.equals(key);
        }

        @Specialization(guards = "compareStrings(key, cachedKey)", limit = "2")
        protected static Object lookupConstantMRO(Object klass, @SuppressWarnings("unused") String key,
                        @Cached("key") @SuppressWarnings("unused") String cachedKey,
                        @Cached("create(key)") LookupAttributeInMRONode lookup) {
            return lookup.execute(klass);
        }

        @Specialization(replaces = "lookupConstantMRO")
        protected Object lookupInBuiltinType(PythonBuiltinClassType klass, Object key,
                        @Cached ReadAttributeFromDynamicObjectNode readAttrNode) {
            return findAttr(PythonContext.get(this), klass, key, readAttrNode);
        }

        @Specialization(replaces = "lookupConstantMRO")
        protected static Object lookupGeneric(Object klass, Object key,
                        @Cached GetMroStorageNode getMroNode,
                        @Cached(value = "createForceType()", uncached = "getUncachedForceType()") ReadAttributeFromObjectNode readAttrNode) {
            return lookup(klass, key, getMroNode, readAttrNode, false);
        }

        public static LookupAttributeInMRONode.Dynamic create() {
            return LookupAttributeInMRONodeGen.DynamicNodeGen.create();
        }

        public static LookupAttributeInMRONode.Dynamic getUncached() {
            return LookupAttributeInMRONodeGen.DynamicNodeGen.getUncached();
        }
    }

    private final boolean skipPythonClasses;
    protected final String key;
    @Child private TypeNodes.IsSameTypeNode isSameTypeNode = IsSameTypeNodeGen.create();
    @Child private GetMroStorageNode getMroNode;

    public LookupAttributeInMRONode(String key, boolean skipPythonClasses) {
        this.key = key;
        this.skipPythonClasses = skipPythonClasses;
    }

    public static LookupAttributeInMRONode create(String key) {
        return LookupAttributeInMRONodeGen.create(key, false);
    }

    /**
     * Specific case to facilitate lookup on native and built-in classes only. This is useful for
     * certain slot wrappers.
     */
    public static LookupAttributeInMRONode createForLookupOfUnmanagedClasses(String key) {
        return LookupAttributeInMRONodeGen.create(key, true);
    }

    protected static Object findAttr(Python3Core core, PythonBuiltinClassType klass, Object key) {
        return findAttr(core, klass, key, ReadAttributeFromDynamicObjectNode.getUncached());
    }

    public static Object findAttr(Python3Core core, PythonBuiltinClassType klass, Object key, ReadAttributeFromDynamicObjectNode readAttrNode) {
        PythonBuiltinClassType current = klass;
        Object value = PNone.NO_VALUE;
        while (current != null) {
            value = readAttrNode.execute(core.lookupType(current), key);
            if (value != PNone.NO_VALUE) {
                return value;
            }
            current = current.getBase();
        }
        return value;
    }

    @Specialization(guards = {"klass == cachedKlass"}, limit = "getAttributeAccessInlineCacheMaxDepth()", assumptions = "singleContextAssumption()")
    protected static Object lookupPBCTCached(@SuppressWarnings("unused") PythonBuiltinClassType klass,
                    @Cached("klass") @SuppressWarnings("unused") PythonBuiltinClassType cachedKlass,
                    @Cached("findAttr(getContext(), cachedKlass, key)") Object cachedValue) {
        return cachedValue;
    }

    protected static boolean canCache(Object value) {
        return value instanceof Long ||
                        value instanceof Integer ||
                        value instanceof Boolean ||
                        value instanceof Double ||
                        value instanceof PNone;
    }

    @Specialization(guards = {"klass == cachedKlass", "canCache(cachedValue)"}, limit = "getAttributeAccessInlineCacheMaxDepth()")
    protected static Object lookupPBCTCachedMulti(@SuppressWarnings("unused") PythonBuiltinClassType klass,
                    @Cached("klass") @SuppressWarnings("unused") PythonBuiltinClassType cachedKlass,
                    @Cached("findAttr(getContext(), cachedKlass, key)") Object cachedValue) {
        return cachedValue;
    }

    public static PythonBuiltinClassType findOwnerInMro(Python3Core core, PythonBuiltinClassType klass, Object key) {
        PythonBuiltinClassType current = klass;
        ReadAttributeFromDynamicObjectNode readNode = ReadAttributeFromDynamicObjectNode.getUncached();
        while (current != null) {
            if (readNode.execute(core.lookupType(current), key) != PNone.NO_VALUE) {
                return current;
            }
            current = current.getBase();
        }
        return null;
    }

    @Specialization(replaces = "lookupPBCTCached", guards = "klass == cachedKlass", limit = "getAttributeAccessInlineCacheMaxDepth()")
    protected Object lookupPBCTCachedOwner(@SuppressWarnings("unused") PythonBuiltinClassType klass,
                    @Cached("klass") @SuppressWarnings("unused") PythonBuiltinClassType cachedKlass,
                    @Cached("findOwnerInMro(getContext(), cachedKlass, key)") PythonBuiltinClassType ownerKlass,
                    @Cached ReadAttributeFromDynamicObjectNode readAttrNode) {
        if (ownerKlass == null) {
            return PNone.NO_VALUE;
        } else {
            return readAttrNode.execute(PythonContext.get(this).lookupType(ownerKlass), key);
        }
    }

    @Specialization(replaces = "lookupPBCTCachedOwner")
    protected Object lookupPBCTGeneric(PythonBuiltinClassType klass,
                    @Cached ReadAttributeFromDynamicObjectNode readAttrNode) {
        return findAttr(PythonContext.get(this), klass, key, readAttrNode);
    }

    // PythonClass specializations:

    static final class AttributeAssumptionPair {
        public final Assumption assumption;
        public final Object value;

        AttributeAssumptionPair(Assumption assumption, Object value) {
            this.assumption = assumption;
            this.value = value;
        }
    }

    protected AttributeAssumptionPair findAttrAndAssumptionInMRO(Object klass) {
        CompilerAsserts.neverPartOfCompilation();
        // - avoid cases when attributes are stored in a dict containing elements
        // with a potential MRO sideeffect on access.
        // Also note that attr should not be read more than once.
        // - assuming that keys/elements can't be added or replaced in a class dict.
        // (PythonMangedClass returns MappingProxy, which is read-only). Native classes could
        // possibly do so, but for now leaving it as it is.
        PDict dict;
        if (klass instanceof PythonAbstractNativeObject) {
            Object nativedict = CExtNodes.GetTypeMemberNode.getUncached().execute(klass, NativeMember.TP_DICT);
            dict = nativedict == PNone.NO_VALUE ? null : (PDict) nativedict;
        } else {
            dict = GetDictIfExistsNode.getUncached().execute(klass);
        }
        if (dict != null && HashingStorageLibrary.getUncached().hasSideEffect(dict.getDictStorage())) {
            return null;
        }
        MroSequenceStorage mro = getMro(klass);
        Assumption attrAssumption = mro.createAttributeInMROFinalAssumption(key);
        for (int i = 0; i < mro.length(); i++) {
            Object clsObj = mro.getItemNormalized(i);
            if (i > 0) {
                assert clsObj != klass : "MRO chain is incorrect: '" + klass + "' was found at position " + i;
                getMro(clsObj).addAttributeInMROFinalAssumption(key, attrAssumption);
            }
            if (skipPythonClasses && clsObj instanceof PythonClass) {
                continue;
            }
            Object value = ReadAttributeFromObjectNode.getUncachedForceType().execute(clsObj, key);
            if (value != PNone.NO_VALUE) {
                return new AttributeAssumptionPair(attrAssumption, value);
            }
        }
        return new AttributeAssumptionPair(attrAssumption, PNone.NO_VALUE);
    }

    @Specialization(guards = {"isSameType(cachedKlass, klass)", "cachedAttrInMROInfo != null"}, //
                    limit = "getAttributeAccessInlineCacheMaxDepth()", //
                    assumptions = {"cachedAttrInMROInfo.assumption", "singleContextAssumption()"})
    protected static Object lookupConstantMROCached(@SuppressWarnings("unused") Object klass,
                    @Cached("klass") @SuppressWarnings("unused") Object cachedKlass,
                    @Cached("findAttrAndAssumptionInMRO(cachedKlass)") AttributeAssumptionPair cachedAttrInMROInfo) {
        return cachedAttrInMROInfo.value;
    }

    public MroShapeLookupResult lookupInMroShape(MroShape shape, Object klass) {
        assert MroShape.validate(klass, PythonLanguage.get(this));
        return shape.lookup(key);
    }

    // This specialization works well only for multi-context mode
    // Note: MroShape creation and updates are disabled in multi-context mode, see
    // PythonClass#initializeMroShape
    @Specialization(guards = {"!singleContextAssumption().isValid()", "cachedMroShape != null", "klass.getMroShape() == cachedMroShape"}, //
                    limit = "getAttributeAccessInlineCacheMaxDepth()")
    protected Object lookupConstantMROShape(PythonClass klass,
                    @SuppressWarnings("unused") @Cached("klass.getMroShape()") MroShape cachedMroShape,
                    @Cached("lookupInMroShape(cachedMroShape, klass)") MroShapeLookupResult lookupResult) {
        return lookupResult.getFromMro(getMro(klass), key);
    }

    protected static ReadAttributeFromObjectNode[] create(int size) {
        ReadAttributeFromObjectNode[] nodes = new ReadAttributeFromObjectNode[size];
        for (int i = 0; i < size; i++) {
            nodes[i] = ReadAttributeFromObjectNode.createForceType();
        }
        return nodes;
    }

    @Specialization(guards = {"isSameType(cachedKlass, klass)", "mroLength < 32"}, //
                    limit = "getAttributeAccessInlineCacheMaxDepth()", //
                    replaces = "lookupConstantMROShape", //
                    assumptions = {"lookupStable", "singleContextAssumption()"})
    @ExplodeLoop(kind = ExplodeLoop.LoopExplosionKind.FULL_UNROLL_UNTIL_RETURN)
    protected Object lookupConstantMRO(@SuppressWarnings("unused") Object klass,
                    @Cached("klass") @SuppressWarnings("unused") Object cachedKlass,
                    @Cached("getMro(cachedKlass)") MroSequenceStorage mro,
                    @Cached("mro.getLookupStableAssumption()") @SuppressWarnings("unused") Assumption lookupStable,
                    @Cached("mro.length()") int mroLength,
                    @Cached("create(mroLength)") ReadAttributeFromObjectNode[] readAttrNodes) {
        for (int i = 0; i < mroLength; i++) {
            Object kls = mro.getItemNormalized(i);
            if (skipPythonClasses && kls instanceof PythonClass) {
                continue;
            }
            Object value = readAttrNodes[i].execute(kls, key);
            if (value != PNone.NO_VALUE) {
                return value;
            }
        }
        return PNone.NO_VALUE;
    }

    @Specialization(guards = {"mroLength == cachedMroLength", "cachedMroLength < 32"}, //
                    replaces = {"lookupConstantMROCached", "lookupConstantMRO"}, //
                    limit = "getAttributeAccessInlineCacheMaxDepth()")
    @ExplodeLoop(kind = ExplodeLoop.LoopExplosionKind.FULL_UNROLL_UNTIL_RETURN)
    protected Object lookupCachedLen(@SuppressWarnings("unused") Object klass,
                    @Bind("getMro(klass)") MroSequenceStorage mro,
                    @Bind("mro.length()") @SuppressWarnings("unused") int mroLength,
                    @Cached("mro.length()") int cachedMroLength,
                    @Cached("create(cachedMroLength)") ReadAttributeFromObjectNode[] readAttrNodes) {
        for (int i = 0; i < cachedMroLength; i++) {
            Object kls = mro.getItemNormalized(i);
            if (skipPythonClasses && kls instanceof PythonClass) {
                continue;
            }
            Object value = readAttrNodes[i].execute(kls, key);
            if (value != PNone.NO_VALUE) {
                return value;
            }
        }
        return PNone.NO_VALUE;
    }

    @Specialization(replaces = {"lookupConstantMROCached", "lookupConstantMRO", "lookupCachedLen"})
    @Megamorphic
    protected Object lookupGeneric(Object klass,
                    @Cached("createForceType()") ReadAttributeFromObjectNode readAttrNode) {
        return lookup(klass, key, ensureGetMroNode(), readAttrNode, skipPythonClasses);
    }

    protected GetMroStorageNode ensureGetMroNode() {
        if (getMroNode == null) {
            CompilerDirectives.transferToInterpreterAndInvalidate();
            getMroNode = insert(GetMroStorageNode.create());
        }
        return getMroNode;
    }

    protected MroSequenceStorage getMro(Object clazz) {
        return ensureGetMroNode().execute(clazz);
    }

    @TruffleBoundary
    public static Object lookupSlowPath(Object klass, Object key) {
        return lookup(klass, key, GetMroStorageNode.getUncached(), ReadAttributeFromObjectNode.getUncachedForceType(), false);
    }

    public static Object lookup(Object klass, Object key, GetMroStorageNode getMroNode, ReadAttributeFromObjectNode readAttrNode, boolean skipPythonClasses) {
        MroSequenceStorage mro = getMroNode.execute(klass);
        for (int i = 0; i < mro.length(); i++) {
            Object kls = mro.getItemNormalized(i);
            if (skipPythonClasses && kls instanceof PythonClass) {
                continue;
            }
            Object value = readAttrNode.execute(kls, key);
            if (value != PNone.NO_VALUE) {
                return value;
            }
        }
        return PNone.NO_VALUE;
    }

    protected boolean isSameType(Object cachedKlass, Object klass) {
        return isSameTypeNode.execute(cachedKlass, klass);
    }
}
