Rely upon Constants.CHARSET over Constants.CHARACTER_ENCODING

[egit/zawir.git] / org.spearce.jgit / src / org / spearce / jgit / lib / RepositoryConfig.java

/*
 * Copyright (C) 2007, Dave Watson <dwatson@mimvista.com>
 * Copyright (C) 2008, Robin Rosenberg <robin.rosenberg@dewire.com>
 * Copyright (C) 2008, Shawn O. Pearce <spearce@spearce.org>
 * Copyright (C) 2008, Thad Hughes <thadh@thad.corp.google.com>
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or
 * without modification, are permitted provided that the following
 * conditions are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 *
 * - Redistributions in binary form must reproduce the above
 *   copyright notice, this list of conditions and the following
 *   disclaimer in the documentation and/or other materials provided
 *   with the distribution.
 *
 * - Neither the name of the Git Development Community nor the
 *   names of its contributors may be used to endorse or promote
 *   products derived from this software without specific prior
 *   written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package org.spearce.jgit.lib;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

import org.spearce.jgit.util.FS;

/**
 * An object representing the Git config file.
 *
 * This can be either the repository specific file or the user global
 * file depending on how it is instantiated.
 */
public class RepositoryConfig {
        /**
         * Obtain a new configuration instance for ~/.gitconfig.
         * 
         * @return a new configuration instance to read the user's global
         *         configuration file from their home directory.
         */
        public static RepositoryConfig openUserConfig() {
                return new RepositoryConfig(null, new File(FS.userHome(), ".gitconfig"));
        }

        private final RepositoryConfig baseConfig;

        /** Section name for a remote configuration */
        public static final String REMOTE_SECTION = "remote";

        /** Section name for a branch configuration. */
        public static final String BRANCH_SECTION = "branch";

        private final File configFile;

        private boolean readFile;

        private CoreConfig core;

        private List<Entry> entries;

        private Map<String, Object> byName;

        private static final String MAGIC_EMPTY_VALUE = "%%magic%%empty%%";

        RepositoryConfig(final Repository repo) {
                this(openUserConfig(), FS.resolve(repo.getDirectory(), "config"));
        }

        /**
         * Create a Git configuration file reader/writer/cache for a specific file.
         *
         * @param base
         *            configuration that provides default values if this file does
         *            not set/override a particular key. Often this is the user's
         *            global configuration file, or the system level configuration.
         * @param cfgLocation
         *            path of the file to load (or save).
         */
        public RepositoryConfig(final RepositoryConfig base, final File cfgLocation) {
                baseConfig = base;
                configFile = cfgLocation;
                clear();
        }

        /**
         * @return Core configuration values
         */
        public CoreConfig getCore() {
                return core;
        }

        /**
         * Obtain an integer value from the configuration.
         *
         * @param section
         *            section the key is grouped within.
         * @param name
         *            name of the key to get.
         * @param defaultValue
         *            default value to return if no value was present.
         * @return an integer value from the configuration, or defaultValue.
         */
        public int getInt(final String section, final String name,
                        final int defaultValue) {
                return getInt(section, null, name, defaultValue);
        }

        /**
         * Obtain an integer value from the configuration.
         *
         * @param section
         *            section the key is grouped within.
         * @param subsection
         *            subsection name, such a remote or branch name.
         * @param name
         *            name of the key to get.
         * @param defaultValue
         *            default value to return if no value was present.
         * @return an integer value from the configuration, or defaultValue.
         */
        public int getInt(final String section, String subsection,
                        final String name, final int defaultValue) {
                final String str = getString(section, subsection, name);
                if (str == null)
                        return defaultValue;

                String n = str.trim();
                if (n.length() == 0)
                        return defaultValue;

                int mul = 1;
                switch (Character.toLowerCase(n.charAt(n.length() - 1))) {
                case 'g':
                        mul = 1024 * 1024 * 1024;
                        break;
                case 'm':
                        mul = 1024 * 1024;
                        break;
                case 'k':
                        mul = 1024;
                        break;
                }
                if (mul > 1)
                        n = n.substring(0, n.length() - 1).trim();
                if (n.length() == 0)
                        return defaultValue;

                try {
                        return mul * Integer.parseInt(n);
                } catch (NumberFormatException nfe) {
                        throw new IllegalArgumentException("Invalid integer value: "
                                        + section + "." + name + "=" + str);
                }
        }

        /**
         * Get a boolean value from the git config
         *
         * @param section
         *            section the key is grouped within.
         * @param name
         *            name of the key to get.
         * @param defaultValue
         *            default value to return if no value was present.
         * @return true if any value or defaultValue is true, false for missing or
         *         explicit false
         */
        protected boolean getBoolean(final String section, final String name,
                        final boolean defaultValue) {
                return getBoolean(section, null, name, defaultValue);
        }

        /**
         * Get a boolean value from the git config
         *
         * @param section
         *            section the key is grouped within.
         * @param subsection
         *            subsection name, such a remote or branch name.
         * @param name
         *            name of the key to get.
         * @param defaultValue
         *            default value to return if no value was present.
         * @return true if any value or defaultValue is true, false for missing or
         *         explicit false
         */
        protected boolean getBoolean(final String section, String subsection,
                        final String name, final boolean defaultValue) {
                String n = getRawString(section, subsection, name);
                if (n == null)
                        return defaultValue;

                n = n.toLowerCase();
                if (MAGIC_EMPTY_VALUE.equals(n) || "yes".equals(n) || "true".equals(n) || "1".equals(n)) {
                        return true;
                } else if ("no".equals(n) || "false".equals(n) || "0".equals(n)) {
                        return false;
                } else {
                        throw new IllegalArgumentException("Invalid boolean value: "
                                        + section + "." + name + "=" + n);
                }
        }

        /**
         * @param section
         * @param subsection
         * @param name
         * @return a String value from git config.
         */
        public String getString(final String section, String subsection, final String name) {
                String val = getRawString(section, subsection, name);
                if (MAGIC_EMPTY_VALUE.equals(val)) {
                        return "";
                }
                return val;
        }

        /**
         * @param section
         * @param subsection
         * @param name
         * @return array of zero or more values from the configuration.
         */
        public String[] getStringList(final String section, String subsection,
                        final String name) {
                final Object o = getRawEntry(section, subsection, name);
                if (o instanceof List) {
                        final List lst = (List) o;
                        final String[] r = new String[lst.size()];
                        for (int i = 0; i < r.length; i++) {
                                final String val = ((Entry) lst.get(i)).value;
                                r[i] = MAGIC_EMPTY_VALUE.equals(val) ? "" : val;
                        }
                        return r;
                }

                if (o instanceof Entry) {
                        final String val = ((Entry) o).value;
                        return new String[] { MAGIC_EMPTY_VALUE.equals(val) ? "" : val };
                }

                if (baseConfig != null)
                        return baseConfig.getStringList(section, subsection, name);
                return new String[0];
        }

        private String getRawString(final String section, final String subsection,
                        final String name) {
                final Object o = getRawEntry(section, subsection, name);
                if (o instanceof List) {
                        return ((Entry) ((List) o).get(0)).value;
                } else if (o instanceof Entry) {
                        return ((Entry) o).value;
                } else if (baseConfig != null)
                        return baseConfig.getRawString(section, subsection, name);
                else
                        return null;
        }

        private Object getRawEntry(final String section, final String subsection,
                        final String name) {
                if (!readFile) {
                        try {
                                load();
                        } catch (FileNotFoundException err) {
                                // Oh well. No sense in complaining about it.
                                //
                        } catch (IOException err) {
                                err.printStackTrace();
                        }
                }

                String ss;
                if (subsection != null)
                        ss = "."+subsection.toLowerCase();
                else
                        ss = "";
                final Object o;
                o = byName.get(section.toLowerCase() + ss + "." + name.toLowerCase());
                return o;
        }

        /**
         * Add or modify a configuration value. The parameters will result in a
         * configuration entry like this.
         *
         * <pre>
         * [section &quot;subsection&quot;]
         *         name = value
         * </pre>
         *
         * @param section
         *            section name, e.g "branch"
         * @param subsection
         *            optional subsection value, e.g. a branch name
         * @param name
         *            parameter name, e.g. "filemode"
         * @param value
         *            parameter value, e.g. "true"
         */
        public void setString(final String section, final String subsection,
                        final String name, final String value) {
                setStringList(section, subsection, name, Collections
                                .singletonList(value));
        }

        /**
         * Remove a configuration value.
         * 
         * @param section
         *            section name, e.g "branch"
         * @param subsection
         *            optional subsection value, e.g. a branch name
         * @param name
         *            parameter name, e.g. "filemode"
         */
        public void unsetString(final String section, final String subsection,
                        final String name) {
                setStringList(section, subsection, name, Collections
                                .<String> emptyList());
        }

        /**
         * Set a configuration value.
         * 
         * <pre>
         * [section &quot;subsection&quot;]
         *         name = value
         * </pre>
         * 
         * @param section
         *            section name, e.g "branch"
         * @param subsection
         *            optional subsection value, e.g. a branch name
         * @param name
         *            parameter name, e.g. "filemode"
         * @param values
         *            list of zero or more values for this key.
         */
        public void setStringList(final String section, final String subsection,
                        final String name, final List<String> values) {
                // Update our parsed cache of values for future reference.
                //
                String key = section.toLowerCase();
                if (subsection != null)
                        key += "." + subsection.toLowerCase();
                key += "." + name.toLowerCase();
                if (values.size() == 0)
                        byName.remove(key);
                else if (values.size() == 1) {
                        final Entry e = new Entry();
                        e.base = section;
                        e.extendedBase = subsection;
                        e.name = name;
                        e.value = values.get(0);
                        byName.put(key, e);
                } else {
                        final ArrayList<Entry> eList = new ArrayList<Entry>(values.size());
                        for (final String v : values) {
                                final Entry e = new Entry();
                                e.base = section;
                                e.extendedBase = subsection;
                                e.name = name;
                                e.value = v;
                                eList.add(e);
                        }
                        byName.put(key, eList);
                }

                int entryIndex = 0;
                int valueIndex = 0;
                int insertPosition = -1;

                // Reset the first n Entry objects that match this input name.
                //
                while (entryIndex < entries.size() && valueIndex < values.size()) {
                        final Entry e = entries.get(entryIndex++);
                        if (e.match(section, subsection, name)) {
                                e.value = values.get(valueIndex++);
                                insertPosition = entryIndex;
                        }
                }

                // Remove any extra Entry objects that we no longer need.
                //
                if (valueIndex == values.size() && entryIndex < entries.size()) {
                        while (entryIndex < entries.size()) {
                                final Entry e = entries.get(entryIndex++);
                                if (e.match(section, subsection, name))
                                        entries.remove(--entryIndex);
                        }
                }

                // Insert new Entry objects for additional/new values.
                //
                if (valueIndex < values.size() && entryIndex == entries.size()){
                        if (insertPosition < 0) {
                                // We didn't find a matching key above, but maybe there
                                // is already a section available that matches.  Insert
                                // after the last key of that section.
                                //
                                insertPosition = findSectionEnd(section, subsection);
                        }
                        if (insertPosition < 0) {
                                // We didn't find any matching section header for this key,
                                // so we must create a new section header at the end.
                                //
                                final Entry e = new Entry();
                                e.prefix = null;
                                e.suffix = null;
                                e.base = section;
                                e.extendedBase = subsection;
                                entries.add(e);
                                insertPosition = entries.size();
                        }
                        while (valueIndex < values.size()) {
                                final Entry e = new Entry();
                                e.prefix = null;
                                e.suffix = null;
                                e.base = section;
                                e.extendedBase = subsection;
                                e.name = name;
                                e.value = values.get(valueIndex++);
                                entries.add(insertPosition++, e);
                        }
                }
        }

        private int findSectionEnd(final String section, final String subsection) {
                for (int i = 0; i < entries.size(); i++) {
                        Entry e = entries.get(i);
                        if (e.match(section, subsection, null)) {
                                i++;
                                while (i < entries.size()) {
                                        e = entries.get(i);
                                        if (e.match(section, subsection, e.name))
                                                i++;
                                        else
                                                break;
                                }
                                return i;
                        }
                }
                return -1;
        }

        /**
         * Create a new default config
         */
        public void create() {
                Entry e;

                clear();
                readFile = true;

                e = new Entry();
                e.base = "core";
                add(e);

                e = new Entry();
                e.base = "core";
                e.name = "repositoryformatversion";
                e.value = "0";
                add(e);

                e = new Entry();
                e.base = "core";
                e.name = "filemode";
                e.value = "true";
                add(e);

                core = new CoreConfig(this);
        }

        /**
         * Save config data to the git config file
         *
         * @throws IOException
         */
        public void save() throws IOException {
                final File tmp = new File(configFile.getParentFile(), configFile
                                .getName()
                                + ".lock");
                final PrintWriter r = new PrintWriter(new BufferedWriter(
                                new OutputStreamWriter(new FileOutputStream(tmp),
                                                Constants.CHARSET))) {
                        @Override
                        public void println() {
                                print('\n');
                        }
                };
                boolean ok = false;
                try {
                        final Iterator<Entry> i = entries.iterator();
                        while (i.hasNext()) {
                                final Entry e = i.next();
                                if (e.prefix != null) {
                                        r.print(e.prefix);
                                }
                                if (e.base != null && e.name == null) {
                                        r.print('[');
                                        r.print(e.base);
                                        if (e.extendedBase != null) {
                                                r.print(' ');
                                                r.print('"');
                                                r.print(escapeValue(e.extendedBase));
                                                r.print('"');
                                        }
                                        r.print(']');
                                } else if (e.base != null && e.name != null) {
                                        if (e.prefix == null || "".equals(e.prefix)) {
                                                r.print('\t');
                                        }
                                        r.print(e.name);
                                        if (e.value != null) {
                                                if (!MAGIC_EMPTY_VALUE.equals(e.value)) {
                                                        r.print(" = ");
                                                        r.print(escapeValue(e.value));
                                                }
                                        }
                                        if (e.suffix != null) {
                                                r.print(' ');
                                        }
                                }
                                if (e.suffix != null) {
                                        r.print(e.suffix);
                                }
                                r.println();
                        }
                        ok = true;
                        r.close();
                        if (!tmp.renameTo(configFile)) {
                                configFile.delete();
                                if (!tmp.renameTo(configFile))
                                        throw new IOException("Cannot save config file " + configFile + ", rename failed");
                        }
                } finally {
                        r.close();
                        if (tmp.exists() && !tmp.delete()) {
                                System.err.println("(warning) failed to delete tmp config file: " + tmp);
                        }
                }
                readFile = ok;
        }

        /**
         * Read the config file
         * @throws IOException
         */
        public void load() throws IOException {
                clear();
                readFile = true;
                final BufferedReader r = new BufferedReader(new InputStreamReader(
                                new FileInputStream(configFile), Constants.CHARSET));
                try {
                        Entry last = null;
                        Entry e = new Entry();
                        for (;;) {
                                r.mark(1);
                                int input = r.read();
                                final char in = (char) input;
                                if (-1 == input) {
                                        break;
                                } else if ('\n' == in) {
                                        // End of this entry.
                                        add(e);
                                        if (e.base != null) {
                                                last = e;
                                        }
                                        e = new Entry();
                                } else if (e.suffix != null) {
                                        // Everything up until the end-of-line is in the suffix.
                                        e.suffix += in;
                                } else if (';' == in || '#' == in) {
                                        // The rest of this line is a comment; put into suffix.
                                        e.suffix = String.valueOf(in);
                                } else if (e.base == null && Character.isWhitespace(in)) {
                                        // Save the leading whitespace (if any).
                                        if (e.prefix == null) {
                                                e.prefix = "";
                                        }
                                        e.prefix += in;
                                } else if ('[' == in) {
                                        // This is a group header line.
                                        e.base = readBase(r);
                                        input = r.read();
                                        if ('"' == input) {
                                                e.extendedBase = readValue(r, true, '"');
                                                input = r.read();
                                        }
                                        if (']' != input) {
                                                throw new IOException("Bad group header.");
                                        }
                                        e.suffix = "";
                                } else if (last != null) {
                                        // Read a value.
                                        e.base = last.base;
                                        e.extendedBase = last.extendedBase;
                                        r.reset();
                                        e.name = readName(r);
                                        if (e.name.endsWith("\n")) {
                                                e.name = e.name.substring(0, e.name.length()-1);
                                                e.value = MAGIC_EMPTY_VALUE;
                                        } else 
                                                e.value = readValue(r, false, -1);
                                } else {
                                        throw new IOException("Invalid line in config file.");
                                }
                        }
                } finally {
                        r.close();
                }

                core = new CoreConfig(this);
        }

        private void clear() {
                entries = new ArrayList<Entry>();
                byName = new HashMap<String, Object>();
        }

        @SuppressWarnings("unchecked")
        private void add(final Entry e) {
                entries.add(e);
                if (e.base != null) {
                        final String b = e.base.toLowerCase();
                        final String group;
                        if (e.extendedBase != null) {
                                group = b + "." + e.extendedBase;
                        } else {
                                group = b;
                        }
                        if (e.name != null) {
                                final String n = e.name.toLowerCase();
                                final String key = group + "." + n;
                                final Object o = byName.get(key);
                                if (o == null) {
                                        byName.put(key, e);
                                } else if (o instanceof Entry) {
                                        final ArrayList<Object> l = new ArrayList<Object>();
                                        l.add(o);
                                        l.add(e);
                                        byName.put(key, l);
                                } else if (o instanceof List) {
                                        ((List<Entry>) o).add(e);
                                }
                        }
                }
        }

        private static String escapeValue(final String x) {
                boolean inquote = false;
                int lineStart = 0;
                final StringBuffer r = new StringBuffer(x.length());
                for (int k = 0; k < x.length(); k++) {
                        final char c = x.charAt(k);
                        switch (c) {
                        case '\n':
                                if (inquote) {
                                        r.append('"');
                                        inquote = false;
                                }
                                r.append("\\n\\\n");
                                lineStart = r.length();
                                break;

                        case '\t':
                                r.append("\\t");
                                break;

                        case '\b':
                                r.append("\\b");
                                break;

                        case '\\':
                                r.append("\\\\");
                                break;

                        case '"':
                                r.append("\\\"");
                                break;

                        case ';':
                        case '#':
                                if (!inquote) {
                                        r.insert(lineStart, '"');
                                        inquote = true;
                                }
                                r.append(c);
                                break;

                        case ' ':
                                if (!inquote && r.length() > 0
                                                && r.charAt(r.length() - 1) == ' ') {
                                        r.insert(lineStart, '"');
                                        inquote = true;
                                }
                                r.append(' ');
                                break;

                        default:
                                r.append(c);
                                break;
                        }
                }
                if (inquote) {
                        r.append('"');
                }
                return r.toString();
        }

        private static String readBase(final BufferedReader r) throws IOException {
                final StringBuffer base = new StringBuffer();
                for (;;) {
                        r.mark(1);
                        int c = r.read();
                        if (c < 0) {
                                throw new IOException("Unexpected end of config file.");
                        } else if (']' == c) {
                                r.reset();
                                break;
                        } else if (' ' == c || '\t' == c) {
                                for (;;) {
                                        r.mark(1);
                                        c = r.read();
                                        if (c < 0) {
                                                throw new IOException("Unexpected end of config file.");
                                        } else if ('"' == c) {
                                                r.reset();
                                                break;
                                        } else if (' ' == c || '\t' == c) {
                                                // Skipped...
                                        } else {
                                                throw new IOException("Bad base entry. : " + base + "," + c);
                                        }
                                }
                                break;
                        } else if (Character.isLetterOrDigit((char) c) || '.' == c || '-' == c) {
                                base.append((char) c);
                        } else {
                                throw new IOException("Bad base entry. : " + base + ", " + c);
                        }
                }
                return base.toString();
        }

        private static String readName(final BufferedReader r) throws IOException {
                final StringBuffer name = new StringBuffer();
                for (;;) {
                        r.mark(1);
                        int c = r.read();
                        if (c < 0) {
                                throw new IOException("Unexpected end of config file.");
                        } else if ('=' == c) {
                                break;
                        } else if (' ' == c || '\t' == c) {
                                for (;;) {
                                        r.mark(1);
                                        c = r.read();
                                        if (c < 0) {
                                                throw new IOException("Unexpected end of config file.");
                                        } else if ('=' == c) {
                                                break;
                                        } else if (';' == c || '#' == c || '\n' == c) {
                                                r.reset();
                                                break;
                                        } else if (' ' == c || '\t' == c) {
                                                // Skipped...
                                        } else {
                                                throw new IOException("Bad entry delimiter.");
                                        }
                                }
                                break;
                        } else if (Character.isLetterOrDigit((char) c) || c == '-') {
                                // From the git-config man page:
                                //     The variable names are case-insensitive and only
                                //     alphanumeric characters and - are allowed.
                                name.append((char) c);
                        } else if ('\n' == c) {
                                r.reset();
                                name.append((char) c);
                                break;
                        } else {
                                throw new IOException("Bad config entry name: " + name + (char) c);
                        }
                }
                return name.toString();
        }

        private static String readValue(final BufferedReader r, boolean quote,
                        final int eol) throws IOException {
                final StringBuffer value = new StringBuffer();
                boolean space = false;
                for (;;) {
                        r.mark(1);
                        int c = r.read();
                        if (c < 0) {
                                if (value.length() == 0)
                                        throw new IOException("Unexpected end of config file.");
                                break;
                        }
                        if ('\n' == c) {
                                if (quote) {
                                        throw new IOException("Newline in quotes not allowed.");
                                }
                                r.reset();
                                break;
                        }
                        if (eol == c) {
                                break;
                        }
                        if (!quote) {
                                if (Character.isWhitespace((char) c)) {
                                        space = true;
                                        continue;
                                }
                                if (';' == c || '#' == c) {
                                        r.reset();
                                        break;
                                }
                        }
                        if (space) {
                                if (value.length() > 0) {
                                        value.append(' ');
                                }
                                space = false;
                        }
                        if ('\\' == c) {
                                c = r.read();
                                switch (c) {
                                case -1:
                                        throw new IOException("End of file in escape.");
                                case '\n':
                                        continue;
                                case 't':
                                        value.append('\t');
                                        continue;
                                case 'b':
                                        value.append('\b');
                                        continue;
                                case 'n':
                                        value.append('\n');
                                        continue;
                                case '\\':
                                        value.append('\\');
                                        continue;
                                case '"':
                                        value.append('"');
                                        continue;
                                default:
                                        throw new IOException("Bad escape: " + ((char) c));
                                }
                        }
                        if ('"' == c) {
                                quote = !quote;
                                continue;
                        }
                        value.append((char) c);
                }
                return value.length() > 0 ? value.toString() : null;
        }

        public String toString() {
                return "RepositoryConfig[" + configFile.getPath() + "]";
        }

        static class Entry {
                String prefix;

                String base;

                String extendedBase;

                String name;

                String value;

                String suffix;

                boolean match(final String aBase, final String aExtendedBase,
                                final String aName) {
                        return eq(base, aBase) && eq(extendedBase, aExtendedBase)
                                        && eq(name, aName);
                }

                private static boolean eq(final String a, final String b) {
                        if (a == b)
                                return true;
                        if (a == null || b == null)
                                return false;
                        return a.equals(b);
                }
        }
}