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 * (b) any piece of software and/or hardware listed in the lrgrwrks.txt file if
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 * Software and the Larger Work(s), and to sublicense the foregoing rights on
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package com.oracle.graal.python.lib;

import static com.oracle.graal.python.runtime.exception.PythonErrorType.AttributeError;

import com.oracle.graal.python.builtins.PythonBuiltinClassType;
import com.oracle.graal.python.builtins.objects.PNone;
import com.oracle.graal.python.builtins.objects.PythonAbstractObject;
import com.oracle.graal.python.builtins.objects.function.BuiltinMethodDescriptors;
import com.oracle.graal.python.builtins.objects.type.PythonManagedClass;
import com.oracle.graal.python.builtins.objects.type.SpecialMethodSlot;
import com.oracle.graal.python.nodes.ErrorMessages;
import com.oracle.graal.python.nodes.PRaiseNode;
import com.oracle.graal.python.nodes.attributes.LookupAttributeInMRONode;
import com.oracle.graal.python.nodes.attributes.LookupCallableSlotInMRONode;
import com.oracle.graal.python.nodes.attributes.ReadAttributeFromObjectNode;
import com.oracle.graal.python.nodes.call.special.CallTernaryMethodNode;
import com.oracle.graal.python.nodes.call.special.MaybeBindDescriptorNode;
import com.oracle.graal.python.nodes.call.special.MaybeBindDescriptorNode.BoundDescriptor;
import com.oracle.graal.python.nodes.object.GetClassNode;
import com.oracle.truffle.api.dsl.Bind;
import com.oracle.truffle.api.dsl.Cached;
import com.oracle.truffle.api.dsl.Cached.Shared;
import com.oracle.truffle.api.dsl.GenerateUncached;
import com.oracle.truffle.api.dsl.ImportStatic;
import com.oracle.truffle.api.dsl.Specialization;
import com.oracle.truffle.api.frame.Frame;
import com.oracle.truffle.api.frame.VirtualFrame;
import com.oracle.truffle.api.nodes.Node;
import com.oracle.truffle.api.profiles.BranchProfile;

/**
 * Equivalent of _PyObject_GetMethod. Like CPython, the node uses {@link PyObjectGetAttr} for any
 * object that does not have the generic {@code object.__getattribute__}. For the generic {@code
 * object.__getattribute__} the node inlines the default logic but without binding methods, and
 * falls back to looking into the object dict. Returns something that can be handled by our
 * CallSpecial nodes.
 */
@GenerateUncached
@ImportStatic(SpecialMethodSlot.class)
public abstract class PyObjectGetMethod extends Node {

    public abstract Object execute(Frame frame, Object receiver, String name);

    protected static boolean isObjectGetAttribute(Object lazyClass) {
        Object getattributeSlot = null;
        Object getattrSlot = null;
        if (lazyClass instanceof PythonBuiltinClassType) {
            PythonBuiltinClassType type = (PythonBuiltinClassType) lazyClass;
            getattributeSlot = SpecialMethodSlot.GetAttribute.getValue(type);
            getattrSlot = SpecialMethodSlot.GetAttr.getValue(type);
        } else if (lazyClass instanceof PythonManagedClass) {
            PythonManagedClass type = (PythonManagedClass) lazyClass;
            getattributeSlot = SpecialMethodSlot.GetAttribute.getValue(type);
            getattrSlot = SpecialMethodSlot.GetAttr.getValue(type);
        }
        return getattributeSlot == BuiltinMethodDescriptors.OBJ_GET_ATTRIBUTE && getattrSlot == PNone.NO_VALUE;
    }

    @Specialization(guards = "!isObjectGetAttribute(lazyClass)", limit = "1")
    static Object getGenericAttr(Frame frame, Object receiver, String name,
                    @SuppressWarnings("unused") @Shared("getClassNode") @Cached GetClassNode getClass,
                    @SuppressWarnings("unused") @Bind("getClass.execute(receiver)") Object lazyClass,
                    @Cached PyObjectGetAttr getAttr) {
        return new BoundDescriptor(getAttr.execute(frame, receiver, name));
    }

    @Specialization(guards = {"isObjectGetAttribute(lazyClass)", "name == cachedName"}, limit = "1")
    static Object getFixedAttr(VirtualFrame frame, Object receiver, @SuppressWarnings("unused") String name,
                    @SuppressWarnings("unused") @Shared("getClassNode") @Cached GetClassNode getClass,
                    @Bind("getClass.execute(receiver)") Object lazyClass,
                    @SuppressWarnings("unused") @Cached("name") String cachedName,
                    @Cached("create(name)") LookupAttributeInMRONode lookupNode,
                    @Shared("getDescrClass") @Cached GetClassNode getDescrClass,
                    @Shared("lookupGet") @Cached(parameters = "Get") LookupCallableSlotInMRONode lookupGet,
                    @Shared("lookupSet") @Cached(parameters = "Set") LookupCallableSlotInMRONode lookupSet,
                    @Shared("callGet") @Cached CallTernaryMethodNode callGet,
                    @Shared("readAttr") @Cached ReadAttributeFromObjectNode readAttr,
                    @Shared("raiseNode") @Cached PRaiseNode raiseNode,
                    @Cached BranchProfile hasDescr,
                    @Cached BranchProfile returnDataDescr,
                    @Cached BranchProfile returnAttr,
                    @Cached BranchProfile returnUnboundMethod,
                    @Cached BranchProfile returnBoundDescr) {
        boolean methodFound = false;
        Object descr = lookupNode.execute(lazyClass);
        Object getMethod = PNone.NO_VALUE;
        if (descr != PNone.NO_VALUE) {
            hasDescr.enter();
            if (MaybeBindDescriptorNode.isMethodDescriptor(descr)) {
                methodFound = true;
            } else {
                // lookupGet acts as branch profile for this branch
                Object descrType = getDescrClass.execute(descr);
                getMethod = lookupGet.execute(descrType);
                if (getMethod != PNone.NO_VALUE && lookupSet.execute(descrType) != PNone.NO_VALUE) {
                    returnDataDescr.enter();
                    return new BoundDescriptor(callGet.execute(frame, getMethod, descr, receiver, lazyClass));
                }
            }
        }
        if (receiver instanceof PythonAbstractObject) {
            // readAttr acts as branch profile here
            Object attr = readAttr.execute(receiver, name);
            if (attr != PNone.NO_VALUE) {
                returnAttr.enter();
                return new BoundDescriptor(attr);
            }
        }
        if (methodFound) {
            returnUnboundMethod.enter();
            return descr;
        }
        if (getMethod != PNone.NO_VALUE) {
            // callGet is used twice, and cannot act as the profile here
            returnBoundDescr.enter();
            return new BoundDescriptor(callGet.execute(frame, getMethod, descr, receiver, lazyClass));
        }
        if (descr != PNone.NO_VALUE) {
            return new BoundDescriptor(descr);
        }
        throw raiseNode.raise(AttributeError, ErrorMessages.OBJ_P_HAS_NO_ATTR_S, receiver, name);
    }

    // No explicit branch profiling when we're looking up multiple things
    @Specialization(guards = "isObjectGetAttribute(lazyClass)", replaces = "getFixedAttr", limit = "1")
    static Object getDynamicAttr(Frame frame, Object receiver, String name,
                    @SuppressWarnings("unused") @Shared("getClassNode") @Cached GetClassNode getClass,
                    @Bind("getClass.execute(receiver)") Object lazyClass,
                    @Cached LookupAttributeInMRONode.Dynamic lookupNode,
                    @Shared("getDescrClass") @Cached GetClassNode getDescrClass,
                    @Shared("lookupGet") @Cached(parameters = "Get") LookupCallableSlotInMRONode lookupGet,
                    @Shared("lookupSet") @Cached(parameters = "Set") LookupCallableSlotInMRONode lookupSet,
                    @Shared("callGet") @Cached CallTernaryMethodNode callGet,
                    @Shared("readAttr") @Cached ReadAttributeFromObjectNode readAttr,
                    @Shared("raiseNode") @Cached PRaiseNode raiseNode) {
        boolean methodFound = false;
        Object descr = lookupNode.execute(lazyClass, name);
        Object getMethod = PNone.NO_VALUE;
        if (descr != PNone.NO_VALUE) {
            if (MaybeBindDescriptorNode.isMethodDescriptor(descr)) {
                methodFound = true;
            } else {
                Object descrType = getDescrClass.execute(descr);
                getMethod = lookupGet.execute(descrType);
                if (getMethod != PNone.NO_VALUE && lookupSet.execute(descrType) != PNone.NO_VALUE) {
                    return new BoundDescriptor(callGet.execute(frame, getMethod, descr, receiver, lazyClass));
                }
            }
        }
        if (receiver instanceof PythonAbstractObject) {
            Object attr = readAttr.execute(receiver, name);
            if (attr != PNone.NO_VALUE) {
                return new BoundDescriptor(attr);
            }
        }
        if (methodFound) {
            return descr;
        }
        if (getMethod != PNone.NO_VALUE) {
            return new BoundDescriptor(callGet.execute(frame, getMethod, descr, receiver, lazyClass));
        }
        if (descr != PNone.NO_VALUE) {
            return new BoundDescriptor(descr);
        }
        throw raiseNode.raise(AttributeError, ErrorMessages.OBJ_P_HAS_NO_ATTR_S, receiver, name);
    }
}
