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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * The Universal Permissive License (UPL), Version 1.0
 *
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 * (a) the Software, and
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 * (b) any piece of software and/or hardware listed in the lrgrwrks.txt file if
 * one is included with the Software each a "Larger Work" to which the Software
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 * without restriction, including without limitation the rights to copy, create
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 * Software and the Larger Work(s), and to sublicense the foregoing rights on
 * either these or other terms.
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 * This license is subject to the following condition:
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 * The above copyright notice and either this complete permission notice or at a
 * minimum a reference to the UPL must be included in all copies or substantial
 * portions of the Software.
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package com.oracle.graal.python.lib;

import static com.oracle.graal.python.builtins.PythonBuiltinClassType.DeprecationWarning;
import static com.oracle.graal.python.builtins.PythonBuiltinClassType.TypeError;
import static com.oracle.graal.python.nodes.SpecialMethodNames.T___INDEX__;

import com.oracle.graal.python.builtins.PythonBuiltinClassType;
import com.oracle.graal.python.builtins.modules.WarningsModuleBuiltins;
import com.oracle.graal.python.builtins.objects.PNone;
import com.oracle.graal.python.builtins.objects.cext.PythonAbstractNativeObject;
import com.oracle.graal.python.builtins.objects.ints.PInt;
import com.oracle.graal.python.builtins.objects.type.SpecialMethodSlot;
import com.oracle.graal.python.nodes.ErrorMessages;
import com.oracle.graal.python.nodes.PGuards;
import com.oracle.graal.python.nodes.PNodeWithContext;
import com.oracle.graal.python.nodes.PRaiseNode;
import com.oracle.graal.python.nodes.call.special.CallUnaryMethodNode;
import com.oracle.graal.python.nodes.call.special.LookupSpecialMethodSlotNode;
import com.oracle.graal.python.nodes.classes.IsSubtypeNode;
import com.oracle.graal.python.nodes.object.GetClassNode;
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.EncapsulatingNodeReference;
import com.oracle.truffle.api.nodes.Node;
import com.oracle.truffle.api.nodes.UnexpectedResultException;

/**
 * Equivalent of CPython's {@code PyNumber_Index}. Converts objects to Python integral types (can be
 * {@code int}, {@code long}, {@code boolean}, {@link PInt} or a native integer (
 * {@link PythonAbstractNativeObject}) using their {@code __index__} method. Raises
 * {@code TypeError} if they don't have any.
 */
@ImportStatic(SpecialMethodSlot.class)
@GenerateUncached
public abstract class PyNumberIndexNode extends PNodeWithContext {
    public abstract Object execute(Frame frame, Object object);

    public abstract int executeInt(Frame frame, Object object) throws UnexpectedResultException;

    public abstract long executeLong(Frame frame, Object object) throws UnexpectedResultException;

    @Specialization
    static int doInt(int object) {
        return object;
    }

    @Specialization
    static long doLong(long object) {
        return object;
    }

    @Specialization
    static PInt doPInt(PInt object) {
        return object;
    }

    @Specialization(rewriteOn = UnexpectedResultException.class)
    int doCallIndexInt(VirtualFrame frame, Object object,
                    @Shared("getClass") @Cached GetClassNode getClassNode,
                    @Shared("lookupIndex") @Cached(parameters = "Index") LookupSpecialMethodSlotNode lookupIndex,
                    @Shared("callIndex") @Cached CallUnaryMethodNode callIndex,
                    @Shared("isSubtype") @Cached IsSubtypeNode isSubtype,
                    @Shared("raiseNode") @Cached PRaiseNode raiseNode) throws UnexpectedResultException {
        Object type = getClassNode.execute(object);
        if (isSubtype.execute(type, PythonBuiltinClassType.PInt)) {
            throw new UnexpectedResultException(object);
        }
        Object indexDescr = lookupIndex.execute(frame, type, object);
        if (indexDescr == PNone.NO_VALUE) {
            throw raiseNode.raise(TypeError, ErrorMessages.OBJ_CANNOT_BE_INTERPRETED_AS_INTEGER, object);
        }
        try {
            return PGuards.expectInteger(callIndex.executeObject(frame, indexDescr, object));
        } catch (UnexpectedResultException e) {
            // Implicit CompilerDirectives.transferToInterpreterAndInvalidate()
            EncapsulatingNodeReference nodeRef = EncapsulatingNodeReference.getCurrent();
            Node outerNode = nodeRef.set(this);
            try {
                checkResult(frame, object, e.getResult(), GetClassNode.getUncached(), IsSubtypeNode.getUncached(), PyLongCheckExactNode.getUncached(), PRaiseNode.getUncached(),
                                WarningsModuleBuiltins.WarnNode.getUncached());
                throw e;
            } finally {
                nodeRef.set(outerNode);
            }
        }
    }

    @Specialization(replaces = "doCallIndexInt")
    static Object doCallIndex(VirtualFrame frame, Object object,
                    @Shared("getClass") @Cached GetClassNode getClassNode,
                    @Shared("lookupIndex") @Cached(parameters = "Index") LookupSpecialMethodSlotNode lookupIndex,
                    @Shared("callIndex") @Cached CallUnaryMethodNode callIndex,
                    @Shared("isSubtype") @Cached IsSubtypeNode isSubtype,
                    @Shared("raiseNode") @Cached PRaiseNode raiseNode,
                    @Cached GetClassNode resultClassNode,
                    @Cached IsSubtypeNode resultSubtype,
                    @Cached PyLongCheckExactNode isInt,
                    @Cached WarningsModuleBuiltins.WarnNode warnNode) {
        Object type = getClassNode.execute(object);
        if (isSubtype.execute(type, PythonBuiltinClassType.PInt)) {
            return object;
        }
        Object indexDescr = lookupIndex.execute(frame, type, object);
        if (indexDescr == PNone.NO_VALUE) {
            throw raiseNode.raise(TypeError, ErrorMessages.OBJ_CANNOT_BE_INTERPRETED_AS_INTEGER, object);
        }
        Object result = callIndex.executeObject(frame, indexDescr, object);
        checkResult(frame, object, result, resultClassNode, resultSubtype, isInt, raiseNode, warnNode);
        return result;
    }

    private static void checkResult(VirtualFrame frame, Object originalObject, Object result, GetClassNode getClassNode, IsSubtypeNode isSubtype, PyLongCheckExactNode isInt, PRaiseNode raiseNode,
                    WarningsModuleBuiltins.WarnNode warnNode) {
        if (!isInt.execute(result)) {
            if (!isSubtype.execute(getClassNode.execute(result), PythonBuiltinClassType.PInt)) {
                throw raiseNode.raise(PythonBuiltinClassType.TypeError, ErrorMessages.INDEX_RETURNED_NON_INT, result);
            }
            warnNode.warnFormat(frame, null, DeprecationWarning, 1,
                            ErrorMessages.WARN_P_RETURNED_NON_P, originalObject, T___INDEX__, "int", result, "int");
        }
    }
}
