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 * The Universal Permissive License (UPL), Version 1.0
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 * person obtaining a copy of this software, associated documentation and/or
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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
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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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package com.oracle.truffle.js.runtime;

import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
import com.oracle.truffle.api.exception.AbstractTruffleException;
import com.oracle.truffle.api.interop.ExceptionType;
import com.oracle.truffle.api.interop.InteropLibrary;
import com.oracle.truffle.api.interop.UnsupportedMessageException;
import com.oracle.truffle.js.runtime.util.TRegexUtil;

public final class RegexCompilerInterface {
    private static final String REPEATED_REG_EXP_FLAG_MSG = "Repeated RegExp flag: %c";
    private static final String UNSUPPORTED_REG_EXP_FLAG_MSG = "Invalid regular expression flags";
    private static final String UNSUPPORTED_REG_EXP_FLAG_MSG_NASHORN = "Unsupported RegExp flag: %c";

    private RegexCompilerInterface() {
    }

    public static Object compile(String pattern, String flags, JSContext context, TRegexUtil.CompileRegexNode compileRegexNode) {
        // RegexLanguage does its own validation of the flags. This call to validateFlags only
        // serves the purpose of mimicking the error messages of Nashorn and V8.
        validateFlags(flags, context.getEcmaScriptVersion(), context.isOptionNashornCompatibilityMode());
        try {
            return compileRegexNode.execute(context.getRegexEngine(), pattern, flags);
        } catch (AbstractTruffleException e) {
            throw rethrowAsSyntaxError(e);
        }
    }

    @TruffleBoundary
    public static void validate(JSContext context, String pattern, String flags, int ecmaScriptVersion) {
        if (context.isOptionNashornCompatibilityMode() && !flags.isEmpty()) {
            validateFlags(flags, ecmaScriptVersion, true);
        }
        try {
            TRegexUtil.ValidateRegexNode.getUncached().execute(context.getRegexEngine(), pattern, flags);
        } catch (AbstractTruffleException e) {
            throw rethrowAsSyntaxError(e);
        }
    }

    @SuppressWarnings("fallthrough")
    @TruffleBoundary
    public static void validateFlags(String flags, int ecmaScriptVersion, boolean nashornCompat) {
        boolean ignoreCase = false;
        boolean multiline = false;
        boolean global = false;
        boolean sticky = false;
        boolean unicode = false;
        boolean dotAll = false;

        for (int i = 0; i < flags.length(); i++) {
            char ch = flags.charAt(i);
            boolean repeated;
            switch (ch) {
                case 'i':
                    repeated = ignoreCase;
                    ignoreCase = true;
                    break;
                case 'm':
                    repeated = multiline;
                    multiline = true;
                    break;
                case 'g':
                    repeated = global;
                    global = true;
                    break;
                case 'y':
                    if (ecmaScriptVersion >= 6) {
                        repeated = sticky;
                        sticky = true;
                        break;
                    }
                    // fallthrough
                case 'u':
                    if (ecmaScriptVersion >= 6) {
                        repeated = unicode;
                        unicode = true;
                        break;
                    }
                    // fallthrough
                case 's':
                    if (ecmaScriptVersion >= 9) {
                        repeated = dotAll;
                        dotAll = true;
                        break;
                    }
                    // fallthrough
                default:
                    if (nashornCompat) {
                        throw throwFlagError(UNSUPPORTED_REG_EXP_FLAG_MSG_NASHORN, ch);
                    } else {
                        throw throwFlagError(UNSUPPORTED_REG_EXP_FLAG_MSG);
                    }
            }
            if (repeated) {
                throw throwFlagError(REPEATED_REG_EXP_FLAG_MSG, ch);
            }
        }
    }

    @TruffleBoundary
    private static RuntimeException throwFlagError(String msg, char flag) {
        throw Errors.createSyntaxError(String.format(msg, flag));
    }

    @TruffleBoundary
    private static RuntimeException throwFlagError(String msg) {
        throw Errors.createSyntaxError(msg);
    }

    @TruffleBoundary
    private static AbstractTruffleException rethrowAsSyntaxError(AbstractTruffleException e) {
        ExceptionType exceptionType;
        try {
            exceptionType = InteropLibrary.getUncached().getExceptionType(e);
        } catch (UnsupportedMessageException ume) {
            throw Errors.shouldNotReachHere();
        }
        if (exceptionType == ExceptionType.PARSE_ERROR) {
            throw Errors.createSyntaxError(e.getMessage());
        }
        throw e;
    }
}