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 * reserved comment block

 * DO NOT REMOVE OR ALTER!

 */

/**

 * 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 com.sun.org.apache.xml.internal.security.utils.resolver.implementations;

import java.io.InputStream;

import java.net.URI;

import java.net.URISyntaxException;

import java.nio.file.Files;

import java.nio.file.Paths;

import com.sun.org.apache.xml.internal.security.signature.XMLSignatureInput;

import com.sun.org.apache.xml.internal.security.utils.resolver.ResourceResolverContext;

import com.sun.org.apache.xml.internal.security.utils.resolver.ResourceResolverException;

import com.sun.org.apache.xml.internal.security.utils.resolver.ResourceResolverSpi;

/**

 * A simple ResourceResolver for requests into the local filesystem.

 */

public class ResolverLocalFilesystem extends ResourceResolverSpi {

    private static final int FILE_URI_LENGTH = "file:/".length();

    private static final com.sun.org.slf4j.internal.Logger LOG =

        com.sun.org.slf4j.internal.LoggerFactory.getLogger(ResolverLocalFilesystem.class);

    @Override

    public boolean engineIsThreadSafe() {

        return true;

    }

    /**

     * {@inheritDoc}

     */

    @Override

    public XMLSignatureInput engineResolveURI(ResourceResolverContext context)

        throws ResourceResolverException {

        try {

            // calculate new URI

            URI uriNew = getNewURI(context.uriToResolve, context.baseUri);

            String fileName =

                ResolverLocalFilesystem.translateUriToFilename(uriNew.toString());

            InputStream inputStream = Files.newInputStream(Paths.get(fileName));

            XMLSignatureInput result = new XMLSignatureInput(inputStream);

            result.setSecureValidation(context.secureValidation);

            result.setSourceURI(uriNew.toString());

            return result;

        } catch (Exception e) {

            throw new ResourceResolverException(e, context.uriToResolve, context.baseUri, "generic.EmptyMessage");

        }

    }

    /**

     * Method translateUriToFilename

     *

     * @param uri

     * @return the string of the filename

     */

    private static String translateUriToFilename(String uri) {

        String subStr = uri.substring(FILE_URI_LENGTH);

        if (subStr.indexOf("%20") > -1) {

            int offset = 0;

            int index = 0;

            StringBuilder temp = new StringBuilder(subStr.length());

            do {

                index = subStr.indexOf("%20",offset);

                if (index == -1) {

                    temp.append(subStr.substring(offset));

                } else {

                    temp.append(subStr.substring(offset, index));

                    temp.append(' ');

                    offset = index + 3;

                }

            } while(index != -1);

            subStr = temp.toString();

        }

        if (subStr.charAt(1) == ':') {

            // we're running M$ Windows, so this works fine

            return subStr;

        }

        // we're running some UNIX, so we have to prepend a slash

        return "/" + subStr;

    }

    /**

     * {@inheritDoc}

     */

    public boolean engineCanResolveURI(ResourceResolverContext context) {

        if (context.uriToResolve == null) {

            return false;

        }

        if (context.uriToResolve.equals("") || context.uriToResolve.charAt(0) == '#' ||

            context.uriToResolve.startsWith("http:")) {

            return false;

        }

        try {

            LOG.debug("I was asked whether I can resolve {}", context.uriToResolve);

            if (context.uriToResolve.startsWith("file:") || context.baseUri.startsWith("file:")) {

                LOG.debug("I state that I can resolve {}", context.uriToResolve);

                return true;

            }

        } catch (Exception e) {

            LOG.debug(e.getMessage(), e);

        }

        LOG.debug("But I can't");

        return false;

    }

    private static URI getNewURI(String uri, String baseURI) throws URISyntaxException {

        URI newUri = null;

        if (baseURI == null || "".equals(baseURI)) {

            newUri = new URI(uri);

        } else {

            newUri = new URI(baseURI).resolve(uri);

        }

        // if the URI contains a fragment, ignore it

        if (newUri.getFragment() != null) {

            URI uriNewNoFrag =

                new URI(newUri.getScheme(), newUri.getSchemeSpecificPart(), null);

            return uriNewNoFrag;

        }

        return newUri;

    }

}