com.guardtime.asn1.ContentInfo.java Source code

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Here is the source code for com.guardtime.asn1.ContentInfo.java

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/*
 * $Id: ContentInfo.java 268 2012-08-27 18:31:08Z ahto.truu $
 *
 *
 *
 * Copyright 2008-2011 GuardTime AS
 *
 * This file is part of the GuardTime client SDK.
 *
 * Licensed 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.guardtime.asn1;

import java.io.IOException;
import java.io.InputStream;

import org.bouncycastle.asn1.ASN1Encodable;
import org.bouncycastle.asn1.ASN1Encoding;
import org.bouncycastle.asn1.ASN1InputStream;
import org.bouncycastle.asn1.ASN1Object;

/**
 * <a target="_blank" href="http://www.ietf.org/rfc/rfc2630.txt">RFC 2630</a> structure
 * {@code ContentInfo}.
 * <p>
 * Timestamp token created by timestamping service is internally a content info
 * structure.
 *
 * <pre>
 * ContentInfo ::= SEQUENCE {
 *    contentType     OBJECT IDENTIFIER,
 *    content [0]     EXPLICIT ANY DEFINED BY contentType
 * }
 * </pre>
 *
 * @since 0.4
 */
public final class ContentInfo extends Asn1Wrapper {
    public static final String CONTENT_TYPE = "1.2.840.113549.1.7.2";

    private org.bouncycastle.asn1.cms.ContentInfo contentInfo;
    private String contentType;
    private SignedData content;

    /**
     * Parses a DER-encoded {@code ContentInfo} out from the given input stream.
     *
     * @param in
     *            the input stream to read data from.
     * @return the {@code ContentInfo} object.
     * @throws Asn1FormatException
     *             if the data read from {@code in} does not represent a valid
     *             {@code ContentInfo} object.
     * @throws IOException
     *             if {@code in} throws one.
     */
    public static ContentInfo getInstance(InputStream in) throws Asn1FormatException, IOException {
        if (in == null) {
            throw new IllegalArgumentException("invalid input stream: null");
        }

        try {
            ASN1Object obj = new ASN1InputStream(in).readObject();
            return new ContentInfo(obj);
        } catch (IOException e) {
            if (isAsnParserException(e)) {
                throw new Asn1FormatException("content info has invalid format", e);
            } else {
                throw e;
            }
        } catch (IllegalArgumentException e) {
            if (isAsnParserException(e)) {
                throw new Asn1FormatException("content info has invalid format", e);
            } else {
                throw e;
            }
        }
    }

    /**
     * Returns the DER representation of the {@code ContentInfo}.
     *
     * @return a DER byte array, or {@code null} on error.
     */
    public byte[] getDerEncoded() {
        try {
            return contentInfo.getEncoded(ASN1Encoding.DER);
        } catch (IOException e) {
            return null;
        }
    }

    /**
     * Returns the identifier of the type of the embedded content.
     * <p>
     * It must be equal to {@link #CONTENT_TYPE} for timestamps.
     *
     * @return the content type OID.
     */
    public String getContentType() {
        return contentType;
    }

    /**
     * Returns the actual content embedded in this object.
     * <p>
     * This must be a {@code SignedData} object for timestamps.
     *
     * @return the content.
     */
    public SignedData getContent() {
        return content;
    }

    /**
     * Creates extended timestamp from this timestamp using data from the
     * given certification token.
     *
     * @see CertToken
     *
     * @param certToken
     *            the {@code CertToken} from the GuardTime online verification
     *            service.
     * @return a new updated (extended) timestamp.
     */
    public ContentInfo extend(CertToken certToken) throws Asn1FormatException {
        if (certToken == null) {
            throw new IllegalArgumentException("invalid cert token: null");
        }

        return new ContentInfo(Asn1Util.extend(contentInfo, certToken.getAsn1Token()));
    }

    /**
     * Checks whether the timestamp is extended.
     * <p>
     * An extended timestamp is traceable to a control publication without any
     * extra information. An unextended timestamp needs additional information
     * from the online verification service.
     *
     * @see CertToken
     *
     * @return {@code true} if the timestamp is extended, {@code false}
     *         otherwise.
     */
    public boolean isExtended() {
        return content.isExtended();
    }

    /**
     * Class constructor.
     *
     * @param obj ASN.1 representation of content info.
     *
     * @throws Asn1FormatException if provided ASN.1 object has invalid format.
     */
    ContentInfo(ASN1Encodable obj) throws Asn1FormatException {
        try {
            contentInfo = org.bouncycastle.asn1.cms.ContentInfo.getInstance(obj);

            contentType = contentInfo.getContentType().toString();
            if (!contentType.equals(CONTENT_TYPE)) {
                throw new Asn1FormatException("invalid content type: " + contentType);
            }

            content = new SignedData(contentInfo.getContent());
        } catch (Asn1FormatException e) {
            throw e;
        } catch (Exception e) {
            throw new Asn1FormatException("content info has invalid format", e);
        }
    }
}