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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
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package com.oracle.graal.python.lib;

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.buffer.PythonBufferAccessLibrary;
import com.oracle.graal.python.builtins.objects.bytes.PBytes;
import com.oracle.graal.python.builtins.objects.str.PString;
import com.oracle.graal.python.nodes.ErrorMessages;
import com.oracle.graal.python.nodes.PNodeWithContext;
import com.oracle.graal.python.nodes.PRaiseNode;
import com.oracle.graal.python.nodes.util.CastToTruffleStringNode;
import com.oracle.truffle.api.dsl.Cached;
import com.oracle.truffle.api.dsl.Cached.Shared;
import com.oracle.truffle.api.dsl.Fallback;
import com.oracle.truffle.api.dsl.GenerateUncached;
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.strings.TruffleString;
import com.oracle.truffle.api.strings.TruffleString.Encoding;

/**
 * Equivalent of CPython's {@code PyUnicode_FSDecoder}. Converts a string, bytes or path-like object
 * to a TruffleString path.
 */
@GenerateUncached
public abstract class PyUnicodeFSDecoderNode extends PNodeWithContext {
    public abstract TruffleString execute(Frame frame, Object object);

    @Specialization
    TruffleString doString(TruffleString object,
                    @Shared("byteIndexOfCP") @Cached TruffleString.ByteIndexOfCodePointNode byteIndexOfCodePointNode) {
        return checkString(object, byteIndexOfCodePointNode);
    }

    @Specialization
    TruffleString doPString(PString object,
                    @Cached CastToTruffleStringNode cast,
                    @Shared("byteIndexOfCP") @Cached TruffleString.ByteIndexOfCodePointNode byteIndexOfCodePointNode) {
        return checkString(cast.execute(object), byteIndexOfCodePointNode);
    }

    @Specialization(limit = "1")
    TruffleString doBytes(PBytes object,
                    @CachedLibrary("object") PythonBufferAccessLibrary bufferLib,
                    @Cached TruffleString.FromByteArrayNode fromByteArrayNode,
                    @Cached TruffleString.SwitchEncodingNode switchEncodingNode,
                    @Shared("byteIndexOfCP") @Cached TruffleString.ByteIndexOfCodePointNode byteIndexOfCodePointNode) {
        // TODO PyUnicode_DecodeFSDefault
        TruffleString utf8 = fromByteArrayNode.execute(bufferLib.getCopiedByteArray(object), Encoding.UTF_8, false);
        return checkString(switchEncodingNode.execute(utf8, TS_ENCODING), byteIndexOfCodePointNode);
    }

    @Fallback
    TruffleString doPathLike(VirtualFrame frame, Object object,
                    @Cached PyOSFSPathNode fspathNode,
                    @Cached PyUnicodeFSDecoderNode recursive) {
        Object path = fspathNode.execute(frame, object);
        assert path instanceof TruffleString || path instanceof PString || path instanceof PBytes;
        return recursive.execute(frame, path);
    }

    private TruffleString checkString(TruffleString str, TruffleString.ByteIndexOfCodePointNode byteIndexOfCodePointNode) {
        if (byteIndexOfCodePointNode.execute(str, 0, 0, str.byteLength(TS_ENCODING), TS_ENCODING) >= 0) {
            throw PRaiseNode.raiseUncached(this, ValueError, ErrorMessages.EMBEDDED_NULL_BYTE);
        }
        return str;
    }
}
