/*

 * Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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 * questions.

 */

package java.security;

import java.io.IOException;

import java.math.BigInteger;

import java.util.Arrays;

import java.util.regex.Pattern;

import sun.security.util.*;

/**

 * An attribute associated with a PKCS12 keystore entry.

 * The attribute name is an ASN.1 Object Identifier and the attribute

 * value is a set of ASN.1 types.

 *

 * @since 1.8

 */

public final class PKCS12Attribute implements KeyStore.Entry.Attribute {

    private static final Pattern COLON_SEPARATED_HEX_PAIRS =

        Pattern.compile("^[0-9a-fA-F]{2}(:[0-9a-fA-F]{2})+$");

    private String name;

    private String value;

    private byte[] encoded;

    private int hashValue = -1;

    /**

     * Constructs a PKCS12 attribute from its name and value.

     * The name is an ASN.1 Object Identifier represented as a list of

     * dot-separated integers.

     * A string value is represented as the string itself.

     * A binary value is represented as a string of colon-separated

     * pairs of hexadecimal digits.

     * Multi-valued attributes are represented as a comma-separated

     * list of values, enclosed in square brackets. See

     * {@link Arrays#toString(java.lang.Object[])}.

     * <p>

     * A string value will be DER-encoded as an ASN.1 UTF8String and a

     * binary value will be DER-encoded as an ASN.1 Octet String.

     *

     * @param name the attribute's identifier

     * @param value the attribute's value

     *

     * @exception NullPointerException if {@code name} or {@code value}

     *     is {@code null}

     * @exception IllegalArgumentException if {@code name} or

     *     {@code value} is incorrectly formatted

     */

    public PKCS12Attribute(String name, String value) {

        if (name == null || value == null) {

            throw new NullPointerException();

        }

        // Validate name

        ObjectIdentifier type;

        try {

            type = new ObjectIdentifier(name);

        } catch (IOException e) {

            throw new IllegalArgumentException("Incorrect format: name", e);

        }

        this.name = name;

        // Validate value

        int length = value.length();

        String[] values;

        if (value.charAt(0) == '[' && value.charAt(length - 1) == ']') {

            values = value.substring(1, length - 1).split(", ");

        } else {

            values = new String[]{ value };

        }

        this.value = value;

        try {

            this.encoded = encode(type, values);

        } catch (IOException e) {

            throw new IllegalArgumentException("Incorrect format: value", e);

        }

    }

    /**

     * Constructs a PKCS12 attribute from its ASN.1 DER encoding.

     * The DER encoding is specified by the following ASN.1 definition:

     * <pre>

     *

     * Attribute ::= SEQUENCE {

     *     type   AttributeType,

     *     values SET OF AttributeValue

     * }

     * AttributeType ::= OBJECT IDENTIFIER

     * AttributeValue ::= ANY defined by type

     *

     * </pre>

     *

     * @param encoded the attribute's ASN.1 DER encoding. It is cloned

     *     to prevent subsequent modificaion.

     *

     * @exception NullPointerException if {@code encoded} is

     *     {@code null}

     * @exception IllegalArgumentException if {@code encoded} is

     *     incorrectly formatted

     */

    public PKCS12Attribute(byte[] encoded) {

        if (encoded == null) {

            throw new NullPointerException();

        }

        this.encoded = encoded.clone();

        try {

            parse(encoded);

        } catch (IOException e) {

            throw new IllegalArgumentException("Incorrect format: encoded", e);

        }

    }

    /**

     * Returns the attribute's ASN.1 Object Identifier represented as a

     * list of dot-separated integers.

     *

     * @return the attribute's identifier

     */

    @Override

    public String getName() {

        return name;

    }

    /**

     * Returns the attribute's ASN.1 DER-encoded value as a string.

     * An ASN.1 DER-encoded value is returned in one of the following

     * {@code String} formats:

     * <ul>

     * <li> the DER encoding of a basic ASN.1 type that has a natural

     *      string representation is returned as the string itself.

     *      Such types are currently limited to BOOLEAN, INTEGER,

     *      OBJECT IDENTIFIER, UTCTime, GeneralizedTime and the

     *      following six ASN.1 string types: UTF8String,

     *      PrintableString, T61String, IA5String, BMPString and

     *      GeneralString.

     * <li> the DER encoding of any other ASN.1 type is not decoded but

     *      returned as a binary string of colon-separated pairs of

     *      hexadecimal digits.

     * </ul>

     * Multi-valued attributes are represented as a comma-separated

     * list of values, enclosed in square brackets. See

     * {@link Arrays#toString(java.lang.Object[])}.

     *

     * @return the attribute value's string encoding

     */

    @Override

    public String getValue() {

        return value;

    }

    /**

     * Returns the attribute's ASN.1 DER encoding.

     *

     * @return a clone of the attribute's DER encoding

     */

    public byte[] getEncoded() {

        return encoded.clone();

    }

    /**

     * Compares this {@code PKCS12Attribute} and a specified object for

     * equality.

     *

     * @param obj the comparison object

     *

     * @return true if {@code obj} is a {@code PKCS12Attribute} and

     * their DER encodings are equal.

     */

    @Override

    public boolean equals(Object obj) {

        if (this == obj) {

            return true;

        }

        if (!(obj instanceof PKCS12Attribute)) {

            return false;

        }

        return Arrays.equals(encoded, ((PKCS12Attribute) obj).getEncoded());

    }

    /**

     * Returns the hashcode for this {@code PKCS12Attribute}.

     * The hash code is computed from its DER encoding.

     *

     * @return the hash code

     */

    @Override

    public int hashCode() {

        if (hashValue == -1) {

            Arrays.hashCode(encoded);

        }

        return hashValue;

    }

    /**

     * Returns a string representation of this {@code PKCS12Attribute}.

     *

     * @return a name/value pair separated by an 'equals' symbol

     */

    @Override

    public String toString() {

        return (name + "=" + value);

    }

    private byte[] encode(ObjectIdentifier type, String[] values)

            throws IOException {

        DerOutputStream attribute = new DerOutputStream();

        attribute.putOID(type);

        DerOutputStream attrContent = new DerOutputStream();

        for (String value : values) {

            if (COLON_SEPARATED_HEX_PAIRS.matcher(value).matches()) {

                byte[] bytes =

                    new BigInteger(value.replace(":", ""), 16).toByteArray();

                if (bytes[0] == 0) {

                    bytes = Arrays.copyOfRange(bytes, 1, bytes.length);

                }

                attrContent.putOctetString(bytes);

            } else {

                attrContent.putUTF8String(value);

            }

        }

        attribute.write(DerValue.tag_Set, attrContent);

        DerOutputStream attributeValue = new DerOutputStream();

        attributeValue.write(DerValue.tag_Sequence, attribute);

        return attributeValue.toByteArray();

    }

    private void parse(byte[] encoded) throws IOException {

        DerInputStream attributeValue = new DerInputStream(encoded);

        DerValue[] attrSeq = attributeValue.getSequence(2);

        ObjectIdentifier type = attrSeq[0].getOID();

        DerInputStream attrContent =

            new DerInputStream(attrSeq[1].toByteArray());

        DerValue[] attrValueSet = attrContent.getSet(1);

        String[] values = new String[attrValueSet.length];

        String printableString;

        for (int i = 0; i < attrValueSet.length; i++) {

            if (attrValueSet[i].tag == DerValue.tag_OctetString) {

                values[i] = Debug.toString(attrValueSet[i].getOctetString());

            } else if ((printableString = attrValueSet[i].getAsString())

                != null) {

                values[i] = printableString;

            } else if (attrValueSet[i].tag == DerValue.tag_ObjectId) {

                values[i] = attrValueSet[i].getOID().toString();

            } else if (attrValueSet[i].tag == DerValue.tag_GeneralizedTime) {

                values[i] = attrValueSet[i].getGeneralizedTime().toString();

            } else if (attrValueSet[i].tag == DerValue.tag_UtcTime) {

                values[i] = attrValueSet[i].getUTCTime().toString();

            } else if (attrValueSet[i].tag == DerValue.tag_Integer) {

                values[i] = attrValueSet[i].getBigInteger().toString();

            } else if (attrValueSet[i].tag == DerValue.tag_Boolean) {

                values[i] = String.valueOf(attrValueSet[i].getBoolean());

            } else {

                values[i] = Debug.toString(attrValueSet[i].getDataBytes());

            }

        }

        this.name = type.toString();

        this.value = values.length == 1 ? values[0] : Arrays.toString(values);

    }

}