FastIgnoreRule.java

/*
 * Copyright (C) 2014, 2021 Andrey Loskutov <loskutov@gmx.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.ignore;

import static org.eclipse.jgit.ignore.IMatcher.NO_MATCH;
import static org.eclipse.jgit.ignore.internal.Strings.isDirectoryPattern;
import static org.eclipse.jgit.ignore.internal.Strings.stripTrailing;
import static org.eclipse.jgit.ignore.internal.Strings.stripTrailingWhitespace;

import java.text.MessageFormat;

import org.eclipse.jgit.errors.InvalidPatternException;
import org.eclipse.jgit.ignore.internal.PathMatcher;
import org.eclipse.jgit.internal.JGitText;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * "Fast" (compared with IgnoreRule) git ignore rule implementation supporting
 * also double star {@code **} pattern.
 * <p>
 * This class is immutable and thread safe.
 *
 * @since 3.6
 */
public class FastIgnoreRule {
    private static final Logger LOG = LoggerFactory
            .getLogger(FastIgnoreRule.class);

    /**
     * Character used as default path separator for ignore entries
     */
    public static final char PATH_SEPARATOR = '/';

    private IMatcher matcher;

    private boolean inverse;

    private boolean dirOnly;

    /**
     * Constructor for FastIgnoreRule
     *
     * @param pattern
     *            ignore pattern as described in <a href=
     *            "https://www.kernel.org/pub/software/scm/git/docs/gitignore.html"
     *            >git manual</a>. If pattern is invalid or is not a pattern
     *            (comment), this rule doesn't match anything.
     */
    public FastIgnoreRule(String pattern) {
        this();
        try {
            parse(pattern);
        } catch (InvalidPatternException e) {
            LOG.error(MessageFormat.format(JGitText.get().badIgnorePattern,
                    e.getPattern()), e);
        }
    }

    FastIgnoreRule() {
        matcher = IMatcher.NO_MATCH;
    }

    void parse(String pattern) throws InvalidPatternException {
        if (pattern == null) {
            throw new IllegalArgumentException("Pattern must not be null!"); //$NON-NLS-1$
        }
        if (pattern.length() == 0) {
            dirOnly = false;
            inverse = false;
            this.matcher = NO_MATCH;
            return;
        }
        inverse = pattern.charAt(0) == '!';
        if (inverse) {
            pattern = pattern.substring(1);
            if (pattern.length() == 0) {
                dirOnly = false;
                this.matcher = NO_MATCH;
                return;
            }
        }
        if (pattern.charAt(0) == '#') {
            this.matcher = NO_MATCH;
            dirOnly = false;
            return;
        }
        if (pattern.charAt(0) == '\\' && pattern.length() > 1) {
            char next = pattern.charAt(1);
            if (next == '!' || next == '#') {
                // remove backslash escaping first special characters
                pattern = pattern.substring(1);
            }
        }
        dirOnly = isDirectoryPattern(pattern);
        if (dirOnly) {
            pattern = stripTrailingWhitespace(pattern);
            pattern = stripTrailing(pattern, PATH_SEPARATOR);
            if (pattern.length() == 0) {
                this.matcher = NO_MATCH;
                return;
            }
        }
        this.matcher = PathMatcher.createPathMatcher(pattern,
                Character.valueOf(PATH_SEPARATOR), dirOnly);
    }

    /**
     * Returns true if a match was made. <br>
     * This function does NOT return the actual ignore status of the target!
     * Please consult {@link #getResult()} for the negation status. The actual
     * ignore status may be true or false depending on whether this rule is an
     * ignore rule or a negation rule.
     *
     * @param path
     *            Name pattern of the file, relative to the base directory of
     *            this rule
     * @param directory
     *            Whether the target file is a directory or not
     * @return True if a match was made. This does not necessarily mean that the
     *         target is ignored. Call {@link #getResult() getResult()} for the
     *         result.
     */
    public boolean isMatch(String path, boolean directory) {
        return isMatch(path, directory, false);
    }

    /**
     * Returns true if a match was made. <br>
     * This function does NOT return the actual ignore status of the target!
     * Please consult {@link #getResult()} for the negation status. The actual
     * ignore status may be true or false depending on whether this rule is an
     * ignore rule or a negation rule.
     *
     * @param path
     *            Name pattern of the file, relative to the base directory of
     *            this rule
     * @param directory
     *            Whether the target file is a directory or not
     * @param pathMatch
     *            {@code true} if the match is for the full path: see
     *            {@link IMatcher#matches(String, int, int)}
     * @return True if a match was made. This does not necessarily mean that the
     *         target is ignored. Call {@link #getResult() getResult()} for the
     *         result.
     * @since 4.11
     */
    public boolean isMatch(String path, boolean directory, boolean pathMatch) {
        if (path == null)
            return false;
        if (path.length() == 0)
            return false;
        boolean match = matcher.matches(path, directory, pathMatch);
        return match;
    }

    /**
     * Whether the pattern is just a file name and not a path
     *
     * @return {@code true} if the pattern is just a file name and not a path
     */
    public boolean getNameOnly() {
        return !(matcher instanceof PathMatcher);
    }

    /**
     * Whether the pattern should match directories only
     *
     * @return {@code true} if the pattern should match directories only
     */
    public boolean dirOnly() {
        return dirOnly;
    }

    /**
     * Indicates whether the rule is non-negation or negation.
     *
     * @return True if the pattern had a "!" in front of it
     */
    public boolean getNegation() {
        return inverse;
    }

    /**
     * Indicates whether the rule is non-negation or negation.
     *
     * @return True if the target is to be ignored, false otherwise.
     */
    public boolean getResult() {
        return !inverse;
    }

    /**
     * Whether the rule never matches
     *
     * @return {@code true} if the rule never matches (comment line or broken
     *         pattern)
     * @since 4.1
     */
    public boolean isEmpty() {
        return matcher == NO_MATCH;
    }

    /** {@inheritDoc} */
    @Override
    public String toString() {
        StringBuilder sb = new StringBuilder();
        if (inverse)
            sb.append('!');
        sb.append(matcher);
        if (dirOnly)
            sb.append(PATH_SEPARATOR);
        return sb.toString();

    }

    /** {@inheritDoc} */
    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + (inverse ? 1231 : 1237);
        result = prime * result + (dirOnly ? 1231 : 1237);
        result = prime * result + ((matcher == null) ? 0 : matcher.hashCode());
        return result;
    }

    /** {@inheritDoc} */
    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (!(obj instanceof FastIgnoreRule))
            return false;

        FastIgnoreRule other = (FastIgnoreRule) obj;
        if (inverse != other.inverse)
            return false;
        if (dirOnly != other.dirOnly)
            return false;
        return matcher.equals(other.matcher);
    }
}