src/main/java/org/apache/sling/fsprovider/internal/parser/ContentFileParserUtil.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.sling.fsprovider.internal.parser;

import static org.apache.jackrabbit.vault.util.Constants.DOT_CONTENT_XML;
import static org.apache.sling.fsprovider.internal.parser.ContentFileTypes.JCR_XML_SUFFIX;
import static org.apache.sling.fsprovider.internal.parser.ContentFileTypes.XML_SUFFIX;
import static org.apache.sling.fsprovider.internal.parser.ContentFileTypes.JSON_SUFFIX;

import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.EnumSet;

import org.apache.commons.lang3.StringUtils;
import org.apache.sling.jcr.contentparser.ContentParser;
import org.apache.sling.jcr.contentparser.ContentParserFactory;
import org.apache.sling.jcr.contentparser.ContentType;
import org.apache.sling.jcr.contentparser.JsonParserFeature;
import org.apache.sling.jcr.contentparser.ParserOptions;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Parses files that contains content fragments (e.g. JSON, JCR XML).
 */
class ContentFileParserUtil {
    
    private static final Logger log = LoggerFactory.getLogger(ContentFileParserUtil.class);
    
    private static final ContentParser JSON_PARSER;
    static {
        // workaround for JsonProvider classloader issue until https://issues.apache.org/jira/browse/GERONIMO-6560 is fixed
        ClassLoader oldClassLoader = Thread.currentThread().getContextClassLoader();
        try {
            Thread.currentThread().setContextClassLoader(ContentFileParserUtil.class.getClassLoader());
            // support comments and tick quotes for JSON parsing - same as in JCR content loader 
            JSON_PARSER = ContentParserFactory.create(ContentType.JSON, new ParserOptions()
                    .jsonParserFeatures(EnumSet.of(JsonParserFeature.COMMENTS, JsonParserFeature.QUOTE_TICK)));
        }
        finally {
            Thread.currentThread().setContextClassLoader(oldClassLoader);
        }
    }
    private static final ContentParser JCR_XML_PARSER = ContentParserFactory.create(ContentType.JCR_XML);
    private static final ContentParser XML_PARSER = ContentParserFactory.create(ContentType.XML);
    
    private ContentFileParserUtil() {
        // static methods only
    }
    
    /**
     * Parse content from file.
     * @param file File. Type is detected automatically.
     * @return Content or null if content could not be parsed.
     */
    public static ContentElement parse(File file) {
        if (!file.exists()) {
            return null;
        }
        if (StringUtils.endsWith(file.getName(), JSON_SUFFIX)) {
            return parse(file, ContentType.JSON);
        }
        else if (StringUtils.equals(file.getName(), DOT_CONTENT_XML) || StringUtils.endsWith(file.getName(), JCR_XML_SUFFIX)) {
            return parse(file, ContentType.JCR_XML);
        }
        else if (StringUtils.endsWith(file.getName(), XML_SUFFIX) && !StringUtils.endsWith(file.getName(), JCR_XML_SUFFIX)) {
            return parse(file, ContentType.XML);
        }
        return null;
    }
    
    /**
     * Parse content from file.
     * @param file File. Type is detected automatically.
     * @param contentType Content type
     * @return Content or null if content could not be parsed.
     */
    public static ContentElement parse(File file, ContentType contentType) {
        if (!file.exists()) {
            return null;
        }
        try {
            switch (contentType) {
            case JSON:
                return parse(JSON_PARSER, file);
            case XML:
                return parse(XML_PARSER, file);
            case JCR_XML:
                return parse(JCR_XML_PARSER, file);
               default:
                    throw new IllegalArgumentException("Unexpected content type: " + contentType);
            }
        }
        catch (Throwable ex) {
            log.warn("Error parsing content from " + file.getPath(), ex);
        }
        return null;
    }
    
    private static ContentElement parse(ContentParser contentParser, File file) throws IOException {
        try (FileInputStream fis = new FileInputStream(file);
                BufferedInputStream bis = new BufferedInputStream(fis)) {
            ContentElementHandler handler = new ContentElementHandler();
            contentParser.parse(handler, bis);
            return handler.getRoot();
        }
    }

}