    001/*
    002 * Licensed to the Apache Software Foundation (ASF) under one or more
    003 * contributor license agreements.  See the NOTICE file distributed with
    004 * this work for additional information regarding copyright ownership.
    005 * The ASF licenses this file to You under the Apache License, Version 2.0
    006 * (the "License"); you may not use this file except in compliance with
    007 * the License.  You may obtain a copy of the License at
    008 *
    009 *     http://www.apache.org/licenses/LICENSE-2.0
    010 *
    011 * Unless required by applicable law or agreed to in writing, software
    012 * distributed under the License is distributed on an "AS IS" BASIS,
    013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    014 * See the License for the specific language governing permissions and
    015 * limitations under the License.
    016 */
    017package org.apache.commons.configuration2;
    018
    019import java.io.BufferedReader;
    020import java.io.IOException;
    021import java.io.PrintWriter;
    022import java.io.Reader;
    023import java.io.Writer;
    024import java.util.LinkedHashMap;
    025import java.util.LinkedHashSet;
    026import java.util.List;
    027import java.util.Map;
    028import java.util.Set;
    029import java.util.stream.Collectors;
    030
    031import org.apache.commons.configuration2.convert.ListDelimiterHandler;
    032import org.apache.commons.configuration2.ex.ConfigurationException;
    033import org.apache.commons.configuration2.ex.ConfigurationRuntimeException;
    034import org.apache.commons.configuration2.tree.ImmutableNode;
    035import org.apache.commons.configuration2.tree.InMemoryNodeModel;
    036import org.apache.commons.configuration2.tree.InMemoryNodeModelSupport;
    037import org.apache.commons.configuration2.tree.NodeHandler;
    038import org.apache.commons.configuration2.tree.NodeHandlerDecorator;
    039import org.apache.commons.configuration2.tree.NodeSelector;
    040import org.apache.commons.configuration2.tree.TrackedNodeModel;
    041
    042/**
    043 * <p>
    044 * A specialized hierarchical configuration implementation for parsing ini files.
    045 * </p>
    046 * <p>
    047 * An initialization or ini file is a configuration file typically found on Microsoft's Windows operating system and
    048 * contains data for Windows based applications.
    049 * </p>
    050 * <p>
    051 * Although popularized by Windows, ini files can be used on any system or platform due to the fact that they are merely
    052 * text files that can easily be parsed and modified by both humans and computers.
    053 * </p>
    054 * <p>
    055 * A typical ini file could look something like:
    056 * </p>
    057 *
    058 * <pre>
    059 * [section1]
    060 * ; this is a comment!
    061 * var1 = foo
    062 * var2 = bar
    063 *
    064 * [section2]
    065 * var1 = doo
    066 * </pre>
    067 * <p>
    068 * The format of ini files is fairly straight forward and is composed of three components:
    069 * </p>
    070 * <ul>
    071 * <li><b>Sections:</b> Ini files are split into sections, each section starting with a section declaration. A section
    072 * declaration starts with a '[' and ends with a ']'. Sections occur on one line only.</li>
    073 * <li><b>Parameters:</b> Items in a section are known as parameters. Parameters have a typical {@code key = value}
    074 * format.</li>
    075 * <li><b>Comments:</b> Lines starting with a ';' are assumed to be comments.</li>
    076 * </ul>
    077 * <p>
    078 * There are various implementations of the ini file format by various vendors which has caused a number of differences
    079 * to appear. As far as possible this configuration tries to be lenient and support most of the differences.
    080 * </p>
    081 * <p>
    082 * Some of the differences supported are as follows:
    083 * </p>
    084 * <ul>
    085 * <li><b>Comments:</b> The '#' character is also accepted as a comment signifier.</li>
    086 * <li><b>Key value separator:</b> The ':' character is also accepted in place of '=' to separate keys and values in
    087 * parameters, for example {@code var1 : foo}.</li>
    088 * <li><b>Duplicate sections:</b> Typically duplicate sections are not allowed, this configuration does however support
    089 * this feature. In the event of a duplicate section, the two section's values are merged so that there is only a single
    090 * section. <strong>Note</strong>: This also affects the internal data of the configuration. If it is saved, only a
    091 * single section is written!</li>
    092 * <li><b>Duplicate parameters:</b> Typically duplicate parameters are only allowed if they are in two different
    093 * sections, thus they are local to sections; this configuration simply merges duplicates; if a section has a duplicate
    094 * parameter the values are then added to the key as a list.</li>
    095 * </ul>
    096 * <p>
    097 * Global parameters are also allowed; any parameters declared before a section is declared are added to a global
    098 * section. It is important to note that this global section does not have a name.
    099 * </p>
    100 * <p>
    101 * In all instances, a parameter's key is prepended with its section name and a '.' (period). Thus a parameter named
    102 * "var1" in "section1" will have the key {@code section1.var1} in this configuration. (This is the default behavior.
    103 * Because this is a hierarchical configuration you can change this by setting a different
    104 * {@link org.apache.commons.configuration2.tree.ExpressionEngine}.)
    105 * </p>
    106 * <p>
    107 * <strong>Implementation Details:</strong> Consider the following ini file:
    108 * </p>
    109 * <pre>
    110 *  default = ok
    111 *
    112 *  [section1]
    113 *  var1 = foo
    114 *  var2 = doodle
    115 *
    116 *  [section2]
    117 *  ; a comment
    118 *  var1 = baz
    119 *  var2 = shoodle
    120 *  bad =
    121 *  = worse
    122 *
    123 *  [section3]
    124 *  # another comment
    125 *  var1 : foo
    126 *  var2 : bar
    127 *  var5 : test1
    128 *
    129 *  [section3]
    130 *  var3 = foo
    131 *  var4 = bar
    132 *  var5 = test2
    133 *
    134 *  [sectionSeparators]
    135 *  passwd : abc=def
    136 *  a:b = "value"
    137 * </pre>
    138 * <p>
    139 * This ini file will be parsed without error. Note:
    140 * </p>
    141 * <ul>
    142 * <li>The parameter named "default" is added to the global section, it's value is accessed simply using
    143 * {@code getProperty("default")}.</li>
    144 * <li>Section 1's parameters can be accessed using {@code getProperty("section1.var1")}.</li>
    145 * <li>The parameter named "bad" simply adds the parameter with an empty value.</li>
    146 * <li>The empty key with value "= worse" is added using a key consisting of a single space character. This key is still
    147 * added to section 2 and the value can be accessed using {@code getProperty("section2. ")}, notice the period '.' and
    148 * the space following the section name.</li>
    149 * <li>Section three uses both '=' and ':' to separate keys and values.</li>
    150 * <li>Section 3 has a duplicate key named "var5". The value for this key is [test1, test2], and is represented as a
    151 * List.</li>
    152 * <li>The section called <em>sectionSeparators</em> demonstrates how the configuration deals with multiple occurrences
    153 * of separator characters. Per default the first separator character in a line is detected and used to split the key
    154 * from the value. Therefore the first property definition in this section has the key {@code passwd} and the value
    155 * {@code abc=def}. This default behavior can be changed by using quotes. If there is a separator character before the
    156 * first quote character (ignoring whitespace), this character is used as separator. Thus the second property definition
    157 * in the section has the key {@code a:b} and the value {@code value}.</li>
    158 * </ul>
    159 * <p>
    160 * Internally, this configuration maps the content of the represented ini file to its node structure in the following
    161 * way:
    162 * </p>
    163 * <ul>
    164 * <li>Sections are represented by direct child nodes of the root node.</li>
    165 * <li>For the content of a section, corresponding nodes are created as children of the section node.</li>
    166 * </ul>
    167 * <p>
    168 * This explains how the keys for the properties can be constructed. You can also use other methods of
    169 * {@link HierarchicalConfiguration} for querying or manipulating the hierarchy of configuration nodes, for instance the
    170 * {@code configurationAt()} method for obtaining the data of a specific section. However, be careful that the storage
    171 * scheme described above is not violated (e.g. by adding multiple levels of nodes or inserting duplicate section
    172 * nodes). Otherwise, the special methods for ini configurations may not work correctly!
    173 * </p>
    174 * <p>
    175 * The set of sections in this configuration can be retrieved using the {@code getSections()} method. For obtaining a
    176 * {@code SubnodeConfiguration} with the content of a specific section the {@code getSection()} method can be used.
    177 * </p>
    178 * <p>
    179 * Like other {@code Configuration} implementations, this class uses a {@code Synchronizer} object to control concurrent
    180 * access. By choosing a suitable implementation of the {@code Synchronizer} interface, an instance can be made
    181 * thread-safe or not. Note that access to most of the properties typically set through a builder is not protected by
    182 * the {@code Synchronizer}. The intended usage is that these properties are set once at construction time through the
    183 * builder and after that remain constant. If you wish to change such properties during life time of an instance, you
    184 * have to use the {@code lock()} and {@code unlock()} methods manually to ensure that other threads see your changes.
    185 * </p>
    186 * <p>
    187 * As this class extends {@link AbstractConfiguration}, all basic features like variable interpolation, list handling,
    188 * or data type conversions are available as well. This is described in the chapter
    189 * <a href="https://commons.apache.org/proper/commons-configuration/userguide/howto_basicfeatures.html"> Basic features
    190 * and AbstractConfiguration</a> of the user's guide.
    191 * </p>
    192 * <p>
    193 * Note that this configuration does not support properties with null values. Such properties are considered to be
    194 * section nodes.
    195 * </p>
    196 *
    197 * @since 1.6
    198 */
    199public class INIConfiguration extends BaseHierarchicalConfiguration implements FileBasedConfiguration {
    200
    201    /**
    202     * The default characters that signal the start of a comment line.
    203     */
    204    protected static final String COMMENT_CHARS = "#;";
    205
    206    /**
    207     * The default characters used to separate keys from values.
    208     */
    209    protected static final String SEPARATOR_CHARS = "=:";
    210
    211    /**
    212     * Constant for the line separator.
    213     */
    214    private static final String LINE_SEPARATOR = System.lineSeparator();
    215
    216    /**
    217     * The characters used for quoting values.
    218     */
    219    private static final String QUOTE_CHARACTERS = "\"'";
    220
    221    /**
    222     * The line continuation character.
    223     */
    224    private static final String LINE_CONT = "\\";
    225
    226    /**
    227     * The separator used when writing an INI file.
    228     */
    229    private String separatorUsedInOutput = " = ";
    230
    231    /**
    232     * The separator used when reading an INI file.
    233     */
    234    private String separatorUsedInInput = SEPARATOR_CHARS;
    235
    236    /**
    237     * The characters used to separate keys from values when reading an INI file.
    238     */
    239    private String commentCharsUsedInInput = COMMENT_CHARS;
    240
    241    /**
    242     * The flag for decision, whether inline comments on the section line are allowed.
    243     */
    244    private boolean sectionInLineCommentsAllowed;
    245
    246    /**
    247     * Create a new empty INI Configuration.
    248     */
    249    public INIConfiguration() {
    250    }
    251
    252    /**
    253     * Creates a new instance of {@code INIConfiguration} with the content of the specified
    254     * {@code HierarchicalConfiguration}.
    255     *
    256     * @param c the configuration to be copied
    257     * @since 2.0
    258     */
    259    public INIConfiguration(final HierarchicalConfiguration<ImmutableNode> c) {
    260        super(c);
    261    }
    262
    263    /**
    264     * Create a new empty INI Configuration with option to allow inline comments on the section line.
    265     *
    266     * @param sectionInLineCommentsAllowed when true inline comments on the section line are allowed
    267     */
    268    private INIConfiguration(final boolean sectionInLineCommentsAllowed) {
    269        this.sectionInLineCommentsAllowed = sectionInLineCommentsAllowed;
    270    }
    271
    272    /**
    273     * Creates a new builder.
    274     *
    275     * @return a new builder.
    276     * @since 2.9.0
    277     */
    278    public static Builder builder() {
    279        return new Builder();
    280    }
    281
    282    /**
    283     * Builds instances of INIConfiguration.
    284     *
    285     * @since 2.9.0
    286     */
    287    public static class Builder {
    288
    289        /**
    290         * The flag for decision, whether inline comments on the section line are allowed.
    291         */
    292        private boolean sectionInLineCommentsAllowed;
    293
    294        public Builder setSectionInLineCommentsAllowed(final boolean sectionInLineCommentsAllowed) {
    295            this.sectionInLineCommentsAllowed = sectionInLineCommentsAllowed;
    296            return this;
    297        }
    298
    299        public INIConfiguration build() {
    300            return new INIConfiguration(sectionInLineCommentsAllowed);
    301        }
    302
    303    }
    304
    305    /**
    306     * Gets separator used in INI output. see {@code setSeparatorUsedInOutput} for further explanation
    307     *
    308     * @return the current separator for writing the INI output
    309     * @since 2.2
    310     */
    311    public String getSeparatorUsedInOutput() {
    312        beginRead(false);
    313        try {
    314            return separatorUsedInOutput;
    315        } finally {
    316            endRead();
    317        }
    318    }
    319
    320    /**
    321     * Allows setting the key and value separator which is used for the creation of the resulting INI output
    322     *
    323     * @param separator String of the new separator for INI output
    324     * @since 2.2
    325     */
    326    public void setSeparatorUsedInOutput(final String separator) {
    327        beginWrite(false);
    328        try {
    329            this.separatorUsedInOutput = separator;
    330        } finally {
    331            endWrite();
    332        }
    333    }
    334
    335    /**
    336     * Gets separator used in INI reading. see {@code setSeparatorUsedInInput} for further explanation
    337     *
    338     * @return the current separator for reading the INI input
    339     * @since 2.5
    340     */
    341    public String getSeparatorUsedInInput() {
    342        beginRead(false);
    343        try {
    344            return separatorUsedInInput;
    345        } finally {
    346            endRead();
    347        }
    348    }
    349
    350    /**
    351     * Allows setting the key and value separator which is used in reading an INI file
    352     *
    353     * @param separator String of the new separator for INI reading
    354     * @since 2.5
    355     */
    356    public void setSeparatorUsedInInput(final String separator) {
    357        beginRead(false);
    358        try {
    359            this.separatorUsedInInput = separator;
    360        } finally {
    361            endRead();
    362        }
    363    }
    364
    365    /**
    366     * Gets comment leading separator used in INI reading. see {@code setCommentLeadingCharsUsedInInput} for further
    367     * explanation
    368     *
    369     * @return the current separator for reading the INI input
    370     * @since 2.5
    371     */
    372    public String getCommentLeadingCharsUsedInInput() {
    373        beginRead(false);
    374        try {
    375            return commentCharsUsedInInput;
    376        } finally {
    377            endRead();
    378        }
    379    }
    380
    381    /**
    382     * Allows setting the leading comment separator which is used in reading an INI file
    383     *
    384     * @param separator String of the new separator for INI reading
    385     * @since 2.5
    386     */
    387    public void setCommentLeadingCharsUsedInInput(final String separator) {
    388        beginRead(false);
    389        try {
    390            this.commentCharsUsedInInput = separator;
    391        } finally {
    392            endRead();
    393        }
    394    }
    395
    396    /**
    397     * Save the configuration to the specified writer.
    398     *
    399     * @param writer - The writer to save the configuration to.
    400     * @throws ConfigurationException If an error occurs while writing the configuration
    401     * @throws IOException if an I/O error occurs.
    402     */
    403    @Override
    404    public void write(final Writer writer) throws ConfigurationException, IOException {
    405        final PrintWriter out = new PrintWriter(writer);
    406        boolean first = true;
    407        final String separator = getSeparatorUsedInOutput();
    408
    409        beginRead(false);
    410        try {
    411            for (final ImmutableNode node : getModel().getNodeHandler().getRootNode().getChildren()) {
    412                if (isSectionNode(node)) {
    413                    if (!first) {
    414                        out.println();
    415                    }
    416                    out.print("[");
    417                    out.print(node.getNodeName());
    418                    out.print("]");
    419                    out.println();
    420
    421                    node.forEach(child -> writeProperty(out, child.getNodeName(), child.getValue(), separator));
    422                } else {
    423                    writeProperty(out, node.getNodeName(), node.getValue(), separator);
    424                }
    425                first = false;
    426            }
    427            out.println();
    428            out.flush();
    429        } finally {
    430            endRead();
    431        }
    432    }
    433
    434    /**
    435     * Load the configuration from the given reader. Note that the {@code clear()} method is not called so the configuration
    436     * read in will be merged with the current configuration.
    437     *
    438     * @param in the reader to read the configuration from.
    439     * @throws ConfigurationException If an error occurs while reading the configuration
    440     * @throws IOException if an I/O error occurs.
    441     */
    442    @Override
    443    public void read(final Reader in) throws ConfigurationException, IOException {
    444        final BufferedReader bufferedReader = new BufferedReader(in);
    445        final Map<String, ImmutableNode.Builder> sectionBuilders = new LinkedHashMap<>();
    446        final ImmutableNode.Builder rootBuilder = new ImmutableNode.Builder();
    447
    448        createNodeBuilders(bufferedReader, rootBuilder, sectionBuilders);
    449        final ImmutableNode rootNode = createNewRootNode(rootBuilder, sectionBuilders);
    450        addNodes(null, rootNode.getChildren());
    451    }
    452
    453    /**
    454     * Creates a new root node from the builders constructed while reading the configuration file.
    455     *
    456     * @param rootBuilder the builder for the top-level section
    457     * @param sectionBuilders a map storing the section builders
    458     * @return the root node of the newly created hierarchy
    459     */
    460    private static ImmutableNode createNewRootNode(final ImmutableNode.Builder rootBuilder, final Map<String, ImmutableNode.Builder> sectionBuilders) {
    461        sectionBuilders.forEach((k, v) -> rootBuilder.addChild(v.name(k).create()));
    462        return rootBuilder.create();
    463    }
    464
    465    /**
    466     * Reads the content of an INI file from the passed in reader and creates a structure of builders for constructing the
    467     * {@code ImmutableNode} objects representing the data.
    468     *
    469     * @param in the reader
    470     * @param rootBuilder the builder for the top-level section
    471     * @param sectionBuilders a map storing the section builders
    472     * @throws IOException if an I/O error occurs.
    473     */
    474    private void createNodeBuilders(final BufferedReader in, final ImmutableNode.Builder rootBuilder, final Map<String, ImmutableNode.Builder> sectionBuilders)
    475        throws IOException {
    476        ImmutableNode.Builder sectionBuilder = rootBuilder;
    477        String line = in.readLine();
    478        while (line != null) {
    479            line = line.trim();
    480            if (!isCommentLine(line)) {
    481                if (isSectionLine(line)) {
    482                    final int length = sectionInLineCommentsAllowed ? line.indexOf("]") : line.length() - 1;
    483                    final String section = line.substring(1, length);
    484                    sectionBuilder = sectionBuilders.computeIfAbsent(section, k -> new ImmutableNode.Builder());
    485                } else {
    486                    String key;
    487                    String value = "";
    488                    final int index = findSeparator(line);
    489                    if (index >= 0) {
    490                        key = line.substring(0, index);
    491                        value = parseValue(line.substring(index + 1), in);
    492                    } else {
    493                        key = line;
    494                    }
    495                    key = key.trim();
    496                    if (key.isEmpty()) {
    497                        // use space for properties with no key
    498                        key = " ";
    499                    }
    500                    createValueNodes(sectionBuilder, key, value);
    501                }
    502            }
    503
    504            line = in.readLine();
    505        }
    506    }
    507
    508    /**
    509     * Creates the node(s) for the given key value-pair. If delimiter parsing is enabled, the value string is split if
    510     * possible, and for each single value a node is created. Otherwise only a single node is added to the section.
    511     *
    512     * @param sectionBuilder the section builder for adding new nodes
    513     * @param key the key
    514     * @param value the value string
    515     */
    516    private void createValueNodes(final ImmutableNode.Builder sectionBuilder, final String key, final String value) {
    517        getListDelimiterHandler().split(value, false).forEach(v -> sectionBuilder.addChild(new ImmutableNode.Builder().name(key).value(v).create()));
    518    }
    519
    520    /**
    521     * Writes data about a property into the given stream.
    522     *
    523     * @param out the output stream
    524     * @param key the key
    525     * @param value the value
    526     */
    527    private void writeProperty(final PrintWriter out, final String key, final Object value, final String separator) {
    528        out.print(key);
    529        out.print(separator);
    530        out.print(escapeValue(value.toString()));
    531        out.println();
    532    }
    533
    534    /**
    535     * Parse the value to remove the quotes and ignoring the comment. Example:
    536     *
    537     * <pre>
    538     * &quot;value&quot; ; comment -&gt; value
    539     * </pre>
    540     *
    541     * <pre>
    542     * 'value' ; comment -&gt; value
    543     * </pre>
    544     *
    545     * Note that a comment character is only recognized if there is at least one whitespace character before it. So it can
    546     * appear in the property value, e.g.:
    547     *
    548     * <pre>
    549     * C:\\Windows;C:\\Windows\\system32
    550     * </pre>
    551     *
    552     * @param val the value to be parsed
    553     * @param reader the reader (needed if multiple lines have to be read)
    554     * @throws IOException if an IO error occurs
    555     */
    556    private String parseValue(final String val, final BufferedReader reader) throws IOException {
    557        final StringBuilder propertyValue = new StringBuilder();
    558        boolean lineContinues;
    559        String value = val.trim();
    560
    561        do {
    562            final boolean quoted = value.startsWith("\"") || value.startsWith("'");
    563            boolean stop = false;
    564            boolean escape = false;
    565
    566            final char quote = quoted ? value.charAt(0) : 0;
    567
    568            int i = quoted ? 1 : 0;
    569
    570            final StringBuilder result = new StringBuilder();
    571            char lastChar = 0;
    572            while (i < value.length() && !stop) {
    573                final char c = value.charAt(i);
    574
    575                if (quoted) {
    576                    if ('\\' == c && !escape) {
    577                        escape = true;
    578                    } else if (!escape && quote == c) {
    579                        stop = true;
    580                    } else {
    581                        if (escape && quote == c) {
    582                            escape = false;
    583                        } else if (escape) {
    584                            escape = false;
    585                            result.append('\\');
    586                        }
    587                        result.append(c);
    588                    }
    589                } else if (isCommentChar(c) && Character.isWhitespace(lastChar)) {
    590                    stop = true;
    591                } else {
    592                    result.append(c);
    593                }
    594
    595                i++;
    596                lastChar = c;
    597            }
    598
    599            String v = result.toString();
    600            if (!quoted) {
    601                v = v.trim();
    602                lineContinues = lineContinues(v);
    603                if (lineContinues) {
    604                    // remove trailing "\"
    605                    v = v.substring(0, v.length() - 1).trim();
    606                }
    607            } else {
    608                lineContinues = lineContinues(value, i);
    609            }
    610            propertyValue.append(v);
    611
    612            if (lineContinues) {
    613                propertyValue.append(LINE_SEPARATOR);
    614                value = reader.readLine();
    615            }
    616        } while (lineContinues && value != null);
    617
    618        return propertyValue.toString();
    619    }
    620
    621    /**
    622     * Tests whether the specified string contains a line continuation marker.
    623     *
    624     * @param line the string to check
    625     * @return a flag whether this line continues
    626     */
    627    private static boolean lineContinues(final String line) {
    628        final String s = line.trim();
    629        return s.equals(LINE_CONT) || s.length() > 2 && s.endsWith(LINE_CONT) && Character.isWhitespace(s.charAt(s.length() - 2));
    630    }
    631
    632    /**
    633     * Tests whether the specified string contains a line continuation marker after the specified position. This method
    634     * parses the string to remove a comment that might be present. Then it checks whether a line continuation marker can be
    635     * found at the end.
    636     *
    637     * @param line the line to check
    638     * @param pos the start position
    639     * @return a flag whether this line continues
    640     */
    641    private boolean lineContinues(final String line, final int pos) {
    642        final String s;
    643
    644        if (pos >= line.length()) {
    645            s = line;
    646        } else {
    647            int end = pos;
    648            while (end < line.length() && !isCommentChar(line.charAt(end))) {
    649                end++;
    650            }
    651            s = line.substring(pos, end);
    652        }
    653
    654        return lineContinues(s);
    655    }
    656
    657    /**
    658     * Tests whether the specified character is a comment character.
    659     *
    660     * @param c the character
    661     * @return a flag whether this character starts a comment
    662     */
    663    private boolean isCommentChar(final char c) {
    664        return getCommentLeadingCharsUsedInInput().indexOf(c) >= 0;
    665    }
    666
    667    /**
    668     * Tries to find the index of the separator character in the given string. This method checks for the presence of
    669     * separator characters in the given string. If multiple characters are found, the first one is assumed to be the
    670     * correct separator. If there are quoting characters, they are taken into account, too.
    671     *
    672     * @param line the line to be checked
    673     * @return the index of the separator character or -1 if none is found
    674     */
    675    private int findSeparator(final String line) {
    676        int index = findSeparatorBeforeQuote(line, findFirstOccurrence(line, QUOTE_CHARACTERS));
    677        if (index < 0) {
    678            index = findFirstOccurrence(line, getSeparatorUsedInInput());
    679        }
    680        return index;
    681    }
    682
    683    /**
    684     * Checks for the occurrence of the specified separators in the given line. The index of the first separator is
    685     * returned.
    686     *
    687     * @param line the line to be investigated
    688     * @param separators a string with the separator characters to look for
    689     * @return the lowest index of a separator character or -1 if no separator is found
    690     */
    691    private static int findFirstOccurrence(final String line, final String separators) {
    692        int index = -1;
    693
    694        for (int i = 0; i < separators.length(); i++) {
    695            final char sep = separators.charAt(i);
    696            final int pos = line.indexOf(sep);
    697            if (pos >= 0 && (index < 0 || pos < index)) {
    698                index = pos;
    699            }
    700        }
    701
    702        return index;
    703    }
    704
    705    /**
    706     * Searches for a separator character directly before a quoting character. If the first non-whitespace character before
    707     * a quote character is a separator, it is considered the "real" separator in this line - even if there are other
    708     * separators before.
    709     *
    710     * @param line the line to be investigated
    711     * @param quoteIndex the index of the quote character
    712     * @return the index of the separator before the quote or &lt; 0 if there is none
    713     */
    714    private static int findSeparatorBeforeQuote(final String line, final int quoteIndex) {
    715        int index = quoteIndex - 1;
    716        while (index >= 0 && Character.isWhitespace(line.charAt(index))) {
    717            index--;
    718        }
    719
    720        if (index >= 0 && SEPARATOR_CHARS.indexOf(line.charAt(index)) < 0) {
    721            index = -1;
    722        }
    723
    724        return index;
    725    }
    726
    727    /**
    728     * Escapes the given property value before it is written. This method add quotes around the specified value if it
    729     * contains a comment character and handles list delimiter characters.
    730     *
    731     * @param value the string to be escaped
    732     */
    733    private String escapeValue(final String value) {
    734        return String.valueOf(getListDelimiterHandler().escape(escapeComments(value), ListDelimiterHandler.NOOP_TRANSFORMER));
    735    }
    736
    737    /**
    738     * Escapes comment characters in the given value.
    739     *
    740     * @param value the value to be escaped
    741     * @return the value with comment characters escaped
    742     */
    743    private String escapeComments(final String value) {
    744        final String commentChars = getCommentLeadingCharsUsedInInput();
    745        boolean quoted = false;
    746
    747        for (int i = 0; i < commentChars.length(); i++) {
    748            final char c = commentChars.charAt(i);
    749            if (value.indexOf(c) != -1) {
    750                quoted = true;
    751                break;
    752            }
    753        }
    754
    755        if (quoted) {
    756            return '"' + value.replace("\"", "\\\"") + '"';
    757        }
    758        return value;
    759    }
    760
    761    /**
    762     * Determine if the given line is a comment line.
    763     *
    764     * @param line The line to check.
    765     * @return true if the line is empty or starts with one of the comment characters
    766     */
    767    protected boolean isCommentLine(final String line) {
    768        if (line == null) {
    769            return false;
    770        }
    771        // blank lines are also treated as comment lines
    772        return line.isEmpty() || getCommentLeadingCharsUsedInInput().indexOf(line.charAt(0)) >= 0;
    773    }
    774
    775    /**
    776     * Determine if the given line is a section.
    777     *
    778     * @param line The line to check.
    779     * @return true if the line contains a section
    780     */
    781    protected boolean isSectionLine(final String line) {
    782        if (line == null) {
    783            return false;
    784        }
    785        return sectionInLineCommentsAllowed ? isNonStrictSection(line) : isStrictSection(line);
    786    }
    787
    788    /**
    789     * Determine if the entire given line is a section - inline comments are not allowed.
    790     *
    791     * @param line The line to check.
    792     * @return true if the entire line is a section
    793     */
    794    private static boolean isStrictSection(final String line) {
    795        return line.startsWith("[") && line.endsWith("]");
    796    }
    797
    798    /**
    799     * Determine if the given line contains a section - inline comments are allowed.
    800     *
    801     * @param line The line to check.
    802     * @return true if the line contains a section
    803     */
    804    private static boolean isNonStrictSection(final String line) {
    805        return line.startsWith("[") && line.contains("]");
    806    }
    807
    808    /**
    809     * Gets a set containing the sections in this ini configuration. Note that changes to this set do not affect the
    810     * configuration.
    811     *
    812     * @return a set containing the sections.
    813     */
    814    public Set<String> getSections() {
    815        final Set<String> sections = new LinkedHashSet<>();
    816        boolean globalSection = false;
    817        boolean inSection = false;
    818
    819        beginRead(false);
    820        try {
    821            for (final ImmutableNode node : getModel().getNodeHandler().getRootNode().getChildren()) {
    822                if (isSectionNode(node)) {
    823                    inSection = true;
    824                    sections.add(node.getNodeName());
    825                } else if (!inSection && !globalSection) {
    826                    globalSection = true;
    827                    sections.add(null);
    828                }
    829            }
    830        } finally {
    831            endRead();
    832        }
    833
    834        return sections;
    835    }
    836
    837    /**
    838     * Gets a configuration with the content of the specified section. This provides an easy way of working with a single
    839     * section only. The way this configuration is structured internally, this method is very similar to calling
    840     * {@link HierarchicalConfiguration#configurationAt(String)} with the name of the section in question. There are the
    841     * following differences however:
    842     * <ul>
    843     * <li>This method never throws an exception. If the section does not exist, it is created now. The configuration
    844     * returned in this case is empty.</li>
    845     * <li>If section is contained multiple times in the configuration, the configuration returned by this method is
    846     * initialized with the first occurrence of the section. (This can only happen if {@code addProperty()} has been used in
    847     * a way that does not conform to the storage scheme used by {@code INIConfiguration}. If used correctly, there will not
    848     * be duplicate sections.)</li>
    849     * <li>There is special support for the global section: Passing in <b>null</b> as section name returns a configuration
    850     * with the content of the global section (which may also be empty).</li>
    851     * </ul>
    852     *
    853     * @param name the name of the section in question; <b>null</b> represents the global section
    854     * @return a configuration containing only the properties of the specified section
    855     */
    856    public SubnodeConfiguration getSection(final String name) {
    857        if (name == null) {
    858            return getGlobalSection();
    859        }
    860        try {
    861            return (SubnodeConfiguration) configurationAt(name, true);
    862        } catch (final ConfigurationRuntimeException iex) {
    863            // the passed in key does not map to exactly one node
    864            // obtain the node for the section, create it on demand
    865            final InMemoryNodeModel parentModel = getSubConfigurationParentModel();
    866            final NodeSelector selector = parentModel.trackChildNodeWithCreation(null, name, this);
    867            return createSubConfigurationForTrackedNode(selector, this);
    868        }
    869    }
    870
    871    /**
    872     * Creates a sub configuration for the global section of the represented INI configuration.
    873     *
    874     * @return the sub configuration for the global section
    875     */
    876    private SubnodeConfiguration getGlobalSection() {
    877        final InMemoryNodeModel parentModel = getSubConfigurationParentModel();
    878        final NodeSelector selector = new NodeSelector(null); // selects parent
    879        parentModel.trackNode(selector, this);
    880        final GlobalSectionNodeModel model = new GlobalSectionNodeModel(this, selector);
    881        final SubnodeConfiguration sub = new SubnodeConfiguration(this, model);
    882        initSubConfigurationForThisParent(sub);
    883        return sub;
    884    }
    885
    886    /**
    887     * Checks whether the specified configuration node represents a section.
    888     *
    889     * @param node the node in question
    890     * @return a flag whether this node represents a section
    891     */
    892    private static boolean isSectionNode(final ImmutableNode node) {
    893        return node.getValue() == null;
    894    }
    895
    896    /**
    897     * A specialized node model implementation for the sub configuration representing the global section of the INI file.
    898     * This is a regular {@code TrackedNodeModel} with one exception: The {@code NodeHandler} used by this model applies a
    899     * filter on the children of the root node so that only nodes are visible that are no sub sections.
    900     */
    901    private static final class GlobalSectionNodeModel extends TrackedNodeModel {
    902        /**
    903         * Creates a new instance of {@code GlobalSectionNodeModel} and initializes it with the given underlying model.
    904         *
    905         * @param modelSupport the underlying {@code InMemoryNodeModel}
    906         * @param selector the {@code NodeSelector}
    907         */
    908        public GlobalSectionNodeModel(final InMemoryNodeModelSupport modelSupport, final NodeSelector selector) {
    909            super(modelSupport, selector, true);
    910        }
    911
    912        @Override
    913        public NodeHandler<ImmutableNode> getNodeHandler() {
    914            return new NodeHandlerDecorator<ImmutableNode>() {
    915                @Override
    916                public List<ImmutableNode> getChildren(final ImmutableNode node) {
    917                    final List<ImmutableNode> children = super.getChildren(node);
    918                    return filterChildrenOfGlobalSection(node, children);
    919                }
    920
    921                @Override
    922                public List<ImmutableNode> getChildren(final ImmutableNode node, final String name) {
    923                    final List<ImmutableNode> children = super.getChildren(node, name);
    924                    return filterChildrenOfGlobalSection(node, children);
    925                }
    926
    927                @Override
    928                public int getChildrenCount(final ImmutableNode node, final String name) {
    929                    final List<ImmutableNode> children = name != null ? super.getChildren(node, name) : super.getChildren(node);
    930                    return filterChildrenOfGlobalSection(node, children).size();
    931                }
    932
    933                @Override
    934                public ImmutableNode getChild(final ImmutableNode node, final int index) {
    935                    final List<ImmutableNode> children = super.getChildren(node);
    936                    return filterChildrenOfGlobalSection(node, children).get(index);
    937                }
    938
    939                @Override
    940                public int indexOfChild(final ImmutableNode parent, final ImmutableNode child) {
    941                    final List<ImmutableNode> children = super.getChildren(parent);
    942                    return filterChildrenOfGlobalSection(parent, children).indexOf(child);
    943                }
    944
    945                @Override
    946                protected NodeHandler<ImmutableNode> getDecoratedNodeHandler() {
    947                    return GlobalSectionNodeModel.super.getNodeHandler();
    948                }
    949
    950                /**
    951                 * Filters the child nodes of the global section. This method checks whether the passed in node is the root node of the
    952                 * configuration. If so, from the list of children all nodes are filtered which are section nodes.
    953                 *
    954                 * @param node the node in question
    955                 * @param children the children of this node
    956                 * @return a list with the filtered children
    957                 */
    958                private List<ImmutableNode> filterChildrenOfGlobalSection(final ImmutableNode node, final List<ImmutableNode> children) {
    959                    final List<ImmutableNode> filteredList;
    960                    if (node == getRootNode()) {
    961                        filteredList = children.stream().filter(child -> !isSectionNode(child)).collect(Collectors.toList());
    962                    } else {
    963                        filteredList = children;
    964                    }
    965
    966                    return filteredList;
    967                }
    968            };
    969        }
    970    }
    971}