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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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 * 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
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 * portions of the Software.
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package com.oracle.graal.python.lib;

import static com.oracle.graal.python.builtins.PythonBuiltinClassType.TypeError;
import static com.oracle.graal.python.builtins.PythonBuiltinClassType.ValueError;
import static com.oracle.graal.python.util.PythonUtils.TS_ENCODING;

import com.oracle.graal.python.builtins.objects.PNone;
import com.oracle.graal.python.builtins.objects.common.HashingStorageLibrary;
import com.oracle.graal.python.builtins.objects.common.SequenceStorageNodes;
import com.oracle.graal.python.builtins.objects.dict.PDict;
import com.oracle.graal.python.builtins.objects.list.PList;
import com.oracle.graal.python.builtins.objects.set.PSet;
import com.oracle.graal.python.builtins.objects.str.PString;
import com.oracle.graal.python.builtins.objects.str.StringNodes;
import com.oracle.graal.python.builtins.objects.tuple.PTuple;
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.object.GetClassNode;
import com.oracle.graal.python.nodes.util.CastToJavaIntLossyNode;
import com.oracle.graal.python.runtime.exception.PException;
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.library.CachedLibrary;
import com.oracle.truffle.api.nodes.UnexpectedResultException;
import com.oracle.truffle.api.strings.TruffleString;

/**
 * Equivalent of CPython's {@code PyObject_Size} and {@code PyObject_Length} (alias of the former).
 * Returns length of objects by calling their {@code __len__}. Throws an exception if they don't
 * have any. Coerces the result to size integer using {@link PyNumberAsSizeNode}.
 */
@ImportStatic(SpecialMethodSlot.class)
@GenerateUncached
public abstract class PyObjectSizeNode extends PNodeWithContext {
    public abstract int execute(Frame frame, Object object);

    public abstract int execute(Frame frame, PTuple object);

    protected abstract Object executeObject(Frame frame, Object object);

    @Specialization
    static int doTruffleString(TruffleString str,
                    @Cached TruffleString.CodePointLengthNode codePointLengthNode) {
        return codePointLengthNode.execute(str, TS_ENCODING);
    }

    @Specialization(guards = "cannotBeOverridden(object, getClassNode)", limit = "1")
    static int doList(PList object,
                    @SuppressWarnings("unused") @Cached GetClassNode getClassNode,
                    @Cached SequenceStorageNodes.LenNode lenNode) {
        return lenNode.execute(object.getSequenceStorage());
    }

    @Specialization(guards = "cannotBeOverridden(object, getClassNode)", limit = "1")
    static int doTuple(PTuple object,
                    @SuppressWarnings("unused") @Cached GetClassNode getClassNode,
                    @Cached SequenceStorageNodes.LenNode lenNode) {
        return lenNode.execute(object.getSequenceStorage());
    }

    @Specialization(guards = "cannotBeOverridden(object, getClassNode)", limit = "3")
    static int doDict(PDict object,
                    @SuppressWarnings("unused") @Cached GetClassNode getClassNode,
                    @CachedLibrary("object.getDictStorage()") HashingStorageLibrary lib) {
        return lib.length(object.getDictStorage());
    }

    @Specialization(guards = "cannotBeOverridden(object, getClassNode)", limit = "3")
    static int doSet(PSet object,
                    @SuppressWarnings("unused") @Cached GetClassNode getClassNode,
                    @CachedLibrary("object.getDictStorage()") HashingStorageLibrary lib) {
        return lib.length(object.getDictStorage());
    }

    @Specialization(guards = "cannotBeOverridden(object, getClassNode)", limit = "1")
    static int doPString(PString object,
                    @SuppressWarnings("unused") @Cached GetClassNode getClassNode,
                    @Cached StringNodes.StringLenNode lenNode) {
        return lenNode.execute(object);
    }

    @Specialization(rewriteOn = UnexpectedResultException.class)
    static int doInt(VirtualFrame frame, Object object,
                    @Shared("getClass") @Cached GetClassNode getClassNode,
                    @Shared("lookupLen") @Cached(parameters = "Len") LookupSpecialMethodSlotNode lookupLen,
                    @Shared("callLen") @Cached CallUnaryMethodNode callLen,
                    @Shared("index") @Cached PyNumberIndexNode indexNode,
                    @Shared("castLossy") @Cached CastToJavaIntLossyNode castLossy,
                    @Shared("asSize") @Cached PyNumberAsSizeNode asSizeNode,
                    @Shared("raise") @Cached PRaiseNode raiseNode) throws UnexpectedResultException {
        Object lenDescr = lookupLen.execute(frame, getClassNode.execute(object), object);
        if (lenDescr == PNone.NO_VALUE) {
            throw raiseNode.raise(TypeError, ErrorMessages.OBJ_HAS_NO_LEN, object);
        }
        try {
            return checkLen(raiseNode, PGuards.expectInteger(callLen.executeObject(frame, lenDescr, object)));
        } catch (UnexpectedResultException e) {
            int len = PyObjectSizeNode.convertAndCheckLen(frame, e.getResult(), indexNode, castLossy, asSizeNode, raiseNode);
            throw new UnexpectedResultException(len);
        }
    }

    @Specialization(replaces = "doInt")
    static int doObject(VirtualFrame frame, Object object,
                    @Shared("getClass") @Cached GetClassNode getClassNode,
                    @Shared("lookupLen") @Cached(parameters = "Len") LookupSpecialMethodSlotNode lookupLen,
                    @Shared("callLen") @Cached CallUnaryMethodNode callLen,
                    @Shared("index") @Cached PyNumberIndexNode indexNode,
                    @Shared("castLossy") @Cached CastToJavaIntLossyNode castLossy,
                    @Shared("asSize") @Cached PyNumberAsSizeNode asSizeNode,
                    @Shared("raise") @Cached PRaiseNode raiseNode) {
        Object lenDescr = lookupLen.execute(frame, getClassNode.execute(object), object);
        if (lenDescr == PNone.NO_VALUE) {
            throw raiseNode.raise(TypeError, ErrorMessages.OBJ_HAS_NO_LEN, object);
        }
        Object result = callLen.executeObject(frame, lenDescr, object);
        return PyObjectSizeNode.convertAndCheckLen(frame, result, indexNode, castLossy, asSizeNode, raiseNode);
    }

    static int checkLen(PRaiseNode raiseNode, int len) {
        if (len < 0) {
            throw raiseNode.raise(ValueError, ErrorMessages.LEN_SHOULD_RETURN_GT_ZERO);
        }
        return len;
    }

    public static int convertAndCheckLen(VirtualFrame frame, Object result, PyNumberIndexNode indexNode, CastToJavaIntLossyNode castLossy, PyNumberAsSizeNode asSizeNode, PRaiseNode raiseNode) {
        int len;
        Object index = indexNode.execute(frame, result);
        try {
            len = asSizeNode.executeExact(frame, index);
        } catch (PException e) {
            /*
             * CPython first checks whether the number is negative before converting it to an
             * integer. Comparing PInts is not cheap for us, so we do the conversion first. If the
             * conversion overflowed, we need to do the negativity check before raising the overflow
             * error.
             */
            len = castLossy.execute(index);
            checkLen(raiseNode, len);
            throw e;
        }
        return checkLen(raiseNode, len);
    }

    public static PyObjectSizeNode create() {
        return PyObjectSizeNodeGen.create();
    }

    public static PyObjectSizeNode getUncached() {
        return PyObjectSizeNodeGen.getUncached();
    }
}
