001/*
002 * Copyright (c) 2010, 2022, Oracle and/or its affiliates. All rights reserved.
003 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
004 *
005 * This code is free software; you can redistribute it and/or modify it
006 * under the terms of the GNU General Public License version 2 only, as
007 * published by the Free Software Foundation.  Oracle designates this
008 * particular file as subject to the "Classpath" exception as provided
009 * by Oracle in the LICENSE file that accompanied this code.
010 *
011 * This code is distributed in the hope that it will be useful, but WITHOUT
012 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
013 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
014 * version 2 for more details (a copy is included in the LICENSE file that
015 * accompanied this code).
016 *
017 * You should have received a copy of the GNU General Public License version
018 * 2 along with this work; if not, write to the Free Software Foundation,
019 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
020 *
021 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
022 * or visit www.oracle.com if you need additional information or have any
023 * questions.
024 */
025
026package org.jdrupes.mdoclet.internal.doclets.formats.html.markup;
027
028import java.io.IOException;
029import java.io.Writer;
030
031import org.jdrupes.mdoclet.internal.doclets.toolkit.Content;
032
033/**
034 * Class for containing immutable string content for HTML tags of javadoc output.
035 * Newlines are always represented by {@code \n}.
036 * Any special HTML characters will be escaped if and when the content is written out.
037 */
038public class Text extends Content {
039
040    private final String string;
041
042    public static final Text EMPTY = Text.of("");
043
044    /**
045     * Creates a new object containing immutable text.
046     *
047     * @param content the text content
048     * @return the object
049     */
050    public static Text of(CharSequence content) {
051        return new Text(content);
052    }
053
054    /**
055     * Constructs an immutable text object.
056     *
057     * @param content content for the object
058     */
059    private Text(CharSequence content) {
060        assert checkNewlines(content);
061        string = content.toString();
062    }
063
064    @Override
065    public boolean isEmpty() {
066        return string.isEmpty();
067    }
068
069    @Override
070    public int charCount() {
071        return charCount(string);
072    }
073
074    static int charCount(CharSequence cs) {
075        return cs.length();
076    }
077
078    @Override
079    public String toString() {
080        return string;
081    }
082
083    @Override
084    public boolean write(Writer out, String newline, boolean atNewline)
085            throws IOException {
086        out.write(Entity.escapeHtmlChars(string).replace("\n", newline));
087        return string.endsWith("\n");
088    }
089
090    /**
091     * The newline character, to be used when creating {@code Content} nodes.
092     */
093    public static final String NL = "\n";
094
095    /**
096     * Returns a given string with all newlines in the form {@code \n}.
097     *
098     * The sequences of interest are {@code \n}, {@code \r\n}, and {@code \r}.
099     * {@code \n} is already in the right form, so can be ignored,
100     * leaving code to handle {@code \r\n}, and {@code \r}.
101     *
102     * @param text the string
103     * @return the string with newlines in the form {@code \n}
104     */
105    public static CharSequence normalizeNewlines(CharSequence text) {
106        // fast-track when the input is a string with no \r characters
107        if (text instanceof String s && s.indexOf('\r') != -1) {
108            return text;
109        } else {
110            var sb = new StringBuilder();
111            var s = text.toString();
112            int sLen = s.length();
113            int start = 0;
114            int pos;
115            while ((pos = s.indexOf('\r', start)) != -1) {
116                sb.append(s, start, pos);
117                sb.append('\n');
118                pos++;
119                if (pos < sLen && s.charAt(pos) == '\n') {
120                    pos++;
121                }
122                start = pos;
123            }
124            sb.append(s.substring(start));
125            return sb;
126        }
127    }
128
129    /**
130     * Check for the absence of {@code \r} characters.
131     * @param cs the characters to be checked
132     * @return {@code true} if there are no {@code \r} characters, and {@code false} otherwise
133     */
134    static boolean checkNewlines(CharSequence cs) {
135        return !cs.toString().contains("\r");
136    }
137
138}