GroupHead.java

/*
 * Copyright (C) 2008, Florian Köberle <florianskarten@web.de> and others
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Distribution License v. 1.0 which is available at
 * https://www.eclipse.org/org/documents/edl-v10.php.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

package org.eclipse.jgit.fnmatch;

import java.text.MessageFormat;
import java.util.ArrayList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.eclipse.jgit.errors.InvalidPatternException;
import org.eclipse.jgit.internal.JGitText;

final class GroupHead extends AbstractHead {
    private final List<CharacterPattern> characterClasses;

    private static final Pattern REGEX_PATTERN = Pattern
            .compile("([^-][-][^-]|\\[[.:=].*?[.:=]\\])"); //$NON-NLS-1$

    private final boolean inverse;

    GroupHead(String pattern, String wholePattern)
            throws InvalidPatternException {
        super(false);
        this.characterClasses = new ArrayList<>();
        this.inverse = pattern.startsWith("!"); //$NON-NLS-1$
        if (inverse) {
            pattern = pattern.substring(1);
        }
        final Matcher matcher = REGEX_PATTERN.matcher(pattern);
        while (matcher.find()) {
            final String characterClass = matcher.group(0);
            if (characterClass.length() == 3 && characterClass.charAt(1) == '-') {
                final char start = characterClass.charAt(0);
                final char end = characterClass.charAt(2);
                characterClasses.add(new CharacterRange(start, end));
            } else if (characterClass.equals("[:alnum:]")) { //$NON-NLS-1$
                characterClasses.add(LetterPattern.INSTANCE);
                characterClasses.add(DigitPattern.INSTANCE);
            } else if (characterClass.equals("[:alpha:]")) { //$NON-NLS-1$
                characterClasses.add(LetterPattern.INSTANCE);
            } else if (characterClass.equals("[:blank:]")) { //$NON-NLS-1$
                characterClasses.add(new OneCharacterPattern(' '));
                characterClasses.add(new OneCharacterPattern('\t'));
            } else if (characterClass.equals("[:cntrl:]")) { //$NON-NLS-1$
                characterClasses.add(new CharacterRange('\u0000', '\u001F'));
                characterClasses.add(new OneCharacterPattern('\u007F'));
            } else if (characterClass.equals("[:digit:]")) { //$NON-NLS-1$
                characterClasses.add(DigitPattern.INSTANCE);
            } else if (characterClass.equals("[:graph:]")) { //$NON-NLS-1$
                characterClasses.add(new CharacterRange('\u0021', '\u007E'));
                characterClasses.add(LetterPattern.INSTANCE);
                characterClasses.add(DigitPattern.INSTANCE);
            } else if (characterClass.equals("[:lower:]")) { //$NON-NLS-1$
                characterClasses.add(LowerPattern.INSTANCE);
            } else if (characterClass.equals("[:print:]")) { //$NON-NLS-1$
                characterClasses.add(new CharacterRange('\u0020', '\u007E'));
                characterClasses.add(LetterPattern.INSTANCE);
                characterClasses.add(DigitPattern.INSTANCE);
            } else if (characterClass.equals("[:punct:]")) { //$NON-NLS-1$
                characterClasses.add(PunctPattern.INSTANCE);
            } else if (characterClass.equals("[:space:]")) { //$NON-NLS-1$
                characterClasses.add(WhitespacePattern.INSTANCE);
            } else if (characterClass.equals("[:upper:]")) { //$NON-NLS-1$
                characterClasses.add(UpperPattern.INSTANCE);
            } else if (characterClass.equals("[:xdigit:]")) { //$NON-NLS-1$
                characterClasses.add(new CharacterRange('0', '9'));
                characterClasses.add(new CharacterRange('a', 'f'));
                characterClasses.add(new CharacterRange('A', 'F'));
            } else if (characterClass.equals("[:word:]")) { //$NON-NLS-1$
                characterClasses.add(new OneCharacterPattern('_'));
                characterClasses.add(LetterPattern.INSTANCE);
                characterClasses.add(DigitPattern.INSTANCE);
            } else {
                final String message = MessageFormat.format(
                        JGitText.get().characterClassIsNotSupported,
                        characterClass);
                throw new InvalidPatternException(message, wholePattern);
            }

            pattern = matcher.replaceFirst(""); //$NON-NLS-1$
            matcher.reset(pattern);
        }
        // pattern contains now no ranges
        for (int i = 0; i < pattern.length(); i++) {
            final char c = pattern.charAt(i);
            characterClasses.add(new OneCharacterPattern(c));
        }
    }

    /** {@inheritDoc} */
    @Override
    protected final boolean matches(char c) {
        for (CharacterPattern pattern : characterClasses) {
            if (pattern.matches(c)) {
                return !inverse;
            }
        }
        return inverse;
    }

    private interface CharacterPattern {
        /**
         * @param c
         *            the character to test
         * @return returns true if the character matches a pattern.
         */
        boolean matches(char c);
    }

    private static final class CharacterRange implements CharacterPattern {
        private final char start;

        private final char end;

        CharacterRange(char start, char end) {
            this.start = start;
            this.end = end;
        }

        @Override
        public final boolean matches(char c) {
            return start <= c && c <= end;
        }
    }

    private static final class DigitPattern implements CharacterPattern {
        static final GroupHead.DigitPattern INSTANCE = new DigitPattern();

        @Override
        public final boolean matches(char c) {
            return Character.isDigit(c);
        }
    }

    private static final class LetterPattern implements CharacterPattern {
        static final GroupHead.LetterPattern INSTANCE = new LetterPattern();

        @Override
        public final boolean matches(char c) {
            return Character.isLetter(c);
        }
    }

    private static final class LowerPattern implements CharacterPattern {
        static final GroupHead.LowerPattern INSTANCE = new LowerPattern();

        @Override
        public final boolean matches(char c) {
            return Character.isLowerCase(c);
        }
    }

    private static final class UpperPattern implements CharacterPattern {
        static final GroupHead.UpperPattern INSTANCE = new UpperPattern();

        @Override
        public final boolean matches(char c) {
            return Character.isUpperCase(c);
        }
    }

    private static final class WhitespacePattern implements CharacterPattern {
        static final GroupHead.WhitespacePattern INSTANCE = new WhitespacePattern();

        @Override
        public final boolean matches(char c) {
            return Character.isWhitespace(c);
        }
    }

    private static final class OneCharacterPattern implements CharacterPattern {
        private char expectedCharacter;

        OneCharacterPattern(char c) {
            this.expectedCharacter = c;
        }

        @Override
        public final boolean matches(char c) {
            return this.expectedCharacter == c;
        }
    }

    private static final class PunctPattern implements CharacterPattern {
        static final GroupHead.PunctPattern INSTANCE = new PunctPattern();

        private static String punctCharacters = "-!\"#$%&'()*+,./:;<=>?@[\\]_`{|}~"; //$NON-NLS-1$

        @Override
        public boolean matches(char c) {
            return punctCharacters.indexOf(c) != -1;
        }
    }

}