com.github.fge.uritemplate.parse.VariableSpecParser Maven / Gradle / Ivy

Go to download
/*
 * Copyright (c) 2014, Francis Galiegue ([email protected])
 *
 * This software is dual-licensed under:
 *
 * - the Lesser General Public License (LGPL) version 3.0 or, at your option, any
 *   later version;
 * - the Apache Software License (ASL) version 2.0.
 *
 * The text of this file and of both licenses is available at the root of this
 * project or, if you have the jar distribution, in directory META-INF/, under
 * the names LGPL-3.0.txt and ASL-2.0.txt respectively.
 *
 * Direct link to the sources:
 *
 * - LGPL 3.0: https://www.gnu.org/licenses/lgpl-3.0.txt
 * - ASL 2.0: http://www.apache.org/licenses/LICENSE-2.0.txt
 */

package com.github.fge.uritemplate.parse;

import com.github.fge.msgsimple.bundle.MessageBundle;
import com.github.fge.msgsimple.load.MessageBundles;
import com.github.fge.uritemplate.URITemplateMessageBundle;
import com.github.fge.uritemplate.URITemplateParseException;
import com.github.fge.uritemplate.vars.specs.ExplodedVariable;
import com.github.fge.uritemplate.vars.specs.PrefixVariable;
import com.github.fge.uritemplate.vars.specs.SimpleVariable;
import com.github.fge.uritemplate.vars.specs.VariableSpec;
import com.google.common.base.CharMatcher;
import com.google.common.base.Joiner;
import com.google.common.collect.Lists;

import java.nio.CharBuffer;
import java.util.List;

final class VariableSpecParser
{
    private static final MessageBundle BUNDLE
        = MessageBundles.getBundle(URITemplateMessageBundle.class);

    private static final Joiner JOINER = Joiner.on('.');

    private static final CharMatcher VARCHAR = CharMatcher.inRange('0', '9')
        .or(CharMatcher.inRange('a', 'z')).or(CharMatcher.inRange('A', 'Z'))
        .or(CharMatcher.is('_')).or(CharMatchers.PERCENT).precomputed();
    private static final CharMatcher DOT = CharMatcher.is('.');
    private static final CharMatcher COLON = CharMatcher.is(':');
    private static final CharMatcher STAR = CharMatcher.is('*');
    private static final CharMatcher DIGIT = CharMatcher.inRange('0', '9')
        .precomputed();

    private VariableSpecParser()
    {
    }

    public static VariableSpec parse(final CharBuffer buffer)
        throws URITemplateParseException
    {
        final String name = parseFullName(buffer);

        if (!buffer.hasRemaining())
            return new SimpleVariable(name);

        final char c = buffer.charAt(0);
        if (STAR.matches(c)) {
            buffer.get();
            return new ExplodedVariable(name);
        }

        if (COLON.matches(c)) {
            buffer.get();
            return new PrefixVariable(name, getPrefixLength(buffer));
        }

        return new SimpleVariable(name);
    }

    private static String parseFullName(final CharBuffer buffer)
        throws URITemplateParseException
    {
        final List components = Lists.newArrayList();

        while (true) {
            components.add(readName(buffer));
            if (!buffer.hasRemaining())
                break;
            if (!DOT.matches(buffer.charAt(0)))
                break;
            buffer.get(); // Read the dot
        }

        return JOINER.join(components);
    }

    private static String readName(final CharBuffer buffer)
        throws URITemplateParseException
    {
        final StringBuilder sb = new StringBuilder();

        char c;
        while (buffer.hasRemaining()) {
            c = buffer.charAt(0);
            if (!VARCHAR.matches(c))
                break;
            sb.append(buffer.get());
            if (CharMatchers.PERCENT.matches(c))
                parsePercentEncoded(buffer, sb);
        }

        final String ret = sb.toString();
        if (ret.isEmpty())
            throw new URITemplateParseException(
                BUNDLE.getMessage("parse.emptyVarname"), buffer);
        return ret;
    }

    private static void parsePercentEncoded(final CharBuffer buffer,
        final StringBuilder sb)
        throws URITemplateParseException
    {
        if (buffer.remaining() < 2)
            throw new URITemplateParseException(
                BUNDLE.getMessage("paser.percentShortRead"), buffer, true);

        final char first = buffer.get();
        if (!CharMatchers.HEXDIGIT.matches(first))
            throw new URITemplateParseException(
                BUNDLE.getMessage("parse.percentIllegal"), buffer, true);

        final char second = buffer.get();
        if (!CharMatchers.HEXDIGIT.matches(second))
            throw new URITemplateParseException(
                BUNDLE.getMessage("parse.percentIllegal"), buffer, true);

        sb.append(first).append(second);
    }

    private static int getPrefixLength(final CharBuffer buffer)
        throws URITemplateParseException
    {
        final StringBuilder sb = new StringBuilder();

        char c;
        while (buffer.hasRemaining()) {
            c = buffer.charAt(0);
            if (!DIGIT.matches(c))
                break;
            sb.append(buffer.get());
        }

        final String s = sb.toString();
        if (s.isEmpty())
            throw new URITemplateParseException(
                BUNDLE.getMessage("parse.emptyPrefix"), buffer, true);
        final int ret;
        try {
            ret = Integer.parseInt(s);
            if (ret > 10000)
                throw new NumberFormatException();
            return ret;
        } catch (NumberFormatException ignored) {
            throw new URITemplateParseException(
                BUNDLE.getMessage("parse.prefixTooLarge"), buffer, true);
        }
    }
}