/*
 * @(#)KeyStoreSpi.java	1.22 06/04/07
 *
 * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

package java.security;

import java.io.*;
import java.util.*;

import java.security.KeyStore.*;
import java.security.cert.Certificate;
import java.security.cert.CertificateException;

import javax.crypto.SecretKey;

import javax.security.auth.callback.*;

/**
 * This class defines the <i>Service Provider Interface</i> (<b>SPI</b>)
 * for the <code>KeyStore</code> class.
 * All the abstract methods in this class must be implemented by each
 * cryptographic service provider who wishes to supply the implementation
 * of a keystore for a particular keystore type.
 *
 * @author Jan Luehe
 *
 * @version 1.22, 04/07/06
 *
 * @see KeyStore
 *
 * @since 1.2
 */

public abstract class KeyStoreSpi {

    /**
     * Returns the key associated with the given alias, using the given
     * password to recover it.  The key must have been associated with
     * the alias by a call to <code>setKeyEntry</code>,
     * or by a call to <code>setEntry</code> with a
     * <code>PrivateKeyEntry</code> or <code>SecretKeyEntry</code>.
     *
     * @param alias the alias name
     * @param password the password for recovering the key
     *
     * @return the requested key, or null if the given alias does not exist
     * or does not identify a key-related entry.
     *
     * @exception NoSuchAlgorithmException if the algorithm for recovering the
     * key cannot be found
     * @exception UnrecoverableKeyException if the key cannot be recovered
     * (e.g., the given password is wrong).
     */
    public abstract Key engineGetKey(String alias, char[] password)
	throws NoSuchAlgorithmException, UnrecoverableKeyException;

    /**
     * Returns the certificate chain associated with the given alias.
     * The certificate chain must have been associated with the alias
     * by a call to <code>setKeyEntry</code>,
     * or by a call to <code>setEntry</code> with a
     * <code>PrivateKeyEntry</code>.
     *
     * @param alias the alias name
     *
     * @return the certificate chain (ordered with the user's certificate first
     * and the root certificate authority last), or null if the given alias
     * does not exist or does not contain a certificate chain
     */
    public abstract Certificate[] engineGetCertificateChain(String alias);

    /**
     * Returns the certificate associated with the given alias.
     *
     * <p> If the given alias name identifies an entry
     * created by a call to <code>setCertificateEntry</code>,
     * or created by a call to <code>setEntry</code> with a
     * <code>TrustedCertificateEntry</code>,
     * then the trusted certificate contained in that entry is returned.
     *
     * <p> If the given alias name identifies an entry
     * created by a call to <code>setKeyEntry</code>,
     * or created by a call to <code>setEntry</code> with a
     * <code>PrivateKeyEntry</code>,
     * then the first element of the certificate chain in that entry
     * (if a chain exists) is returned.
     *
     * @param alias the alias name
     *
     * @return the certificate, or null if the given alias does not exist or
     * does not contain a certificate.
     */
    public abstract Certificate engineGetCertificate(String alias);

    /**
     * Returns the creation date of the entry identified by the given alias.
     *
     * @param alias the alias name
     *
     * @return the creation date of this entry, or null if the given alias does
     * not exist
     */
    public abstract Date engineGetCreationDate(String alias);

    /**
     * Assigns the given key to the given alias, protecting it with the given
     * password.
     *
     * <p>If the given key is of type <code>java.security.PrivateKey</code>,
     * it must be accompanied by a certificate chain certifying the
     * corresponding public key.
     *
     * <p>If the given alias already exists, the keystore information
     * associated with it is overridden by the given key (and possibly
     * certificate chain).
     *
     * @param alias the alias name
     * @param key the key to be associated with the alias
     * @param password the password to protect the key
     * @param chain the certificate chain for the corresponding public
     * key (only required if the given key is of type
     * <code>java.security.PrivateKey</code>).
     *
     * @exception KeyStoreException if the given key cannot be protected, or
     * this operation fails for some other reason
     */
    public abstract void engineSetKeyEntry(String alias, Key key,
					   char[] password,
					   Certificate[] chain)
	throws KeyStoreException;

    /**
     * Assigns the given key (that has already been protected) to the given
     * alias.
     *
     * <p>If the protected key is of type
     * <code>java.security.PrivateKey</code>,
     * it must be accompanied by a certificate chain certifying the
     * corresponding public key.
     *
     * <p>If the given alias already exists, the keystore information
     * associated with it is overridden by the given key (and possibly
     * certificate chain).
     *
     * @param alias the alias name
     * @param key the key (in protected format) to be associated with the alias
     * @param chain the certificate chain for the corresponding public
     * key (only useful if the protected key is of type
     * <code>java.security.PrivateKey</code>).
     *
     * @exception KeyStoreException if this operation fails.
     */
    public abstract void engineSetKeyEntry(String alias, byte[] key,
					   Certificate[] chain)
	throws KeyStoreException;

    /**
     * Assigns the given certificate to the given alias.
     *
     * <p> If the given alias identifies an existing entry
     * created by a call to <code>setCertificateEntry</code>,
     * or created by a call to <code>setEntry</code> with a
     * <code>TrustedCertificateEntry</code>,
     * the trusted certificate in the existing entry
     * is overridden by the given certificate.
     *
     * @param alias the alias name
     * @param cert the certificate
     *
     * @exception KeyStoreException if the given alias already exists and does
     * not identify an entry containing a trusted certificate,
     * or this operation fails for some other reason.
     */
    public abstract void engineSetCertificateEntry(String alias,
						   Certificate cert)
	throws KeyStoreException;

    /**
     * Deletes the entry identified by the given alias from this keystore.
     *
     * @param alias the alias name
     *
     * @exception KeyStoreException if the entry cannot be removed.
     */
    public abstract void engineDeleteEntry(String alias)
	throws KeyStoreException;

    /**
     * Lists all the alias names of this keystore.
     *
     * @return enumeration of the alias names
     */
    public abstract Enumeration<String> engineAliases();

    /**
     * Checks if the given alias exists in this keystore.
     *
     * @param alias the alias name
     *
     * @return true if the alias exists, false otherwise
     */
    public abstract boolean engineContainsAlias(String alias);

    /**
     * Retrieves the number of entries in this keystore.
     *
     * @return the number of entries in this keystore
     */
    public abstract int engineSize();

    /**
     * Returns true if the entry identified by the given alias
     * was created by a call to <code>setKeyEntry</code>,
     * or created by a call to <code>setEntry</code> with a
     * <code>PrivateKeyEntry</code> or a <code>SecretKeyEntry</code>.
     *
     * @param alias the alias for the keystore entry to be checked
     *
     * @return true if the entry identified by the given alias is a
     * key-related, false otherwise.
     */
    public abstract boolean engineIsKeyEntry(String alias);

    /**
     * Returns true if the entry identified by the given alias
     * was created by a call to <code>setCertificateEntry</code>,
     * or created by a call to <code>setEntry</code> with a
     * <code>TrustedCertificateEntry</code>.
     *
     * @param alias the alias for the keystore entry to be checked
     *
     * @return true if the entry identified by the given alias contains a
     * trusted certificate, false otherwise.
     */
    public abstract boolean engineIsCertificateEntry(String alias);

    /**
     * Returns the (alias) name of the first keystore entry whose certificate
     * matches the given certificate.
     *
     * <p>This method attempts to match the given certificate with each
     * keystore entry. If the entry being considered was
     * created by a call to <code>setCertificateEntry</code>,
     * or created by a call to <code>setEntry</code> with a
     * <code>TrustedCertificateEntry</code>,
     * then the given certificate is compared to that entry's certificate.
     *
     * <p> If the entry being considered was
     * created by a call to <code>setKeyEntry</code>,
     * or created by a call to <code>setEntry</code> with a
     * <code>PrivateKeyEntry</code>,
     * then the given certificate is compared to the first
     * element of that entry's certificate chain.
     *
     * @param cert the certificate to match with.
     *
     * @return the alias name of the first entry with matching certificate,
     * or null if no such entry exists in this keystore.
     */
    public abstract String engineGetCertificateAlias(Certificate cert);

    /**
     * Stores this keystore to the given output stream, and protects its
     * integrity with the given password.
     *
     * @param stream the output stream to which this keystore is written.
     * @param password the password to generate the keystore integrity check
     *
     * @exception IOException if there was an I/O problem with data
     * @exception NoSuchAlgorithmException if the appropriate data integrity
     * algorithm could not be found
     * @exception CertificateException if any of the certificates included in
     * the keystore data could not be stored
     */
    public abstract void engineStore(OutputStream stream, char[] password)
	throws IOException, NoSuchAlgorithmException, CertificateException;

    /**
     * Stores this keystore using the given
     * <code>KeyStore.LoadStoreParmeter</code>.
     *
     * @param param the <code>KeyStore.LoadStoreParmeter</code>
     *		that specifies how to store the keystore,
     *		which may be <code>null</code>
     *
     * @exception IllegalArgumentException if the given
     *		<code>KeyStore.LoadStoreParmeter</code>
     *		input is not recognized
     * @exception IOException if there was an I/O problem with data
     * @exception NoSuchAlgorithmException if the appropriate data integrity
     *		algorithm could not be found
     * @exception CertificateException if any of the certificates included in
     *		the keystore data could not be stored
     *
     * @since 1.5
     */
    public void engineStore(KeyStore.LoadStoreParameter param)
		throws IOException, NoSuchAlgorithmException,
		CertificateException {
	throw new UnsupportedOperationException();
    }

    /**
     * Loads the keystore from the given input stream.
     *
     * <p>A password may be given to unlock the keystore
     * (e.g. the keystore resides on a hardware token device),
     * or to check the integrity of the keystore data.
     * If a password is not given for integrity checking,
     * then integrity checking is not performed.
     *
     * @param stream the input stream from which the keystore is loaded,
     * or <code>null</code>
     * @param password the password used to check the integrity of
     * the keystore, the password used to unlock the keystore,
     * or <code>null</code>
     *
     * @exception IOException if there is an I/O or format problem with the
     * keystore data, if a password is required but not given,
     * or if the given password was incorrect. If the error is due to a
     * wrong password, the {@link Throwable#getCause cause} of the 
     * <code>IOException</code> should be an 
     * <code>UnrecoverableKeyException</code>
     * @exception NoSuchAlgorithmException if the algorithm used to check
     * the integrity of the keystore cannot be found
     * @exception CertificateException if any of the certificates in the
     * keystore could not be loaded
     */
    public abstract void engineLoad(InputStream stream, char[] password)
	throws IOException, NoSuchAlgorithmException, CertificateException;

    /**
     * Loads the keystore using the given
     * <code>KeyStore.LoadStoreParameter</code>.
     *
     * <p> Note that if this KeyStore has already been loaded, it is
     * reinitialized and loaded again from the given parameter.
     *
     * @param param the <code>KeyStore.LoadStoreParameter</code>
     *		that specifies how to load the keystore,
     *		which may be <code>null</code>
     *
     * @exception IllegalArgumentException if the given
     *		<code>KeyStore.LoadStoreParameter</code>
     *		input is not recognized
     * @exception IOException if there is an I/O or format problem with the
     *		keystore data. If the error is due to an incorrect 
     *         <code>ProtectionParameter</code> (e.g. wrong password)
     *         the {@link Throwable#getCause cause} of the 
     *         <code>IOException</code> should be an 
     *         <code>UnrecoverableKeyException</code>
     * @exception NoSuchAlgorithmException if the algorithm used to check
     *		the integrity of the keystore cannot be found
     * @exception CertificateException if any of the certificates in the
     *		keystore could not be loaded
     *
     * @since 1.5
     */
    public void engineLoad(KeyStore.LoadStoreParameter param)
		throws IOException, NoSuchAlgorithmException,
		CertificateException {

	if (param == null) {
	    engineLoad((InputStream)null, (char[])null);
	    return;
	}
	
	if (param instanceof KeyStore.SimpleLoadStoreParameter) {
	    ProtectionParameter protection = param.getProtectionParameter();
	    char[] password;
	    if (protection instanceof PasswordProtection) {
		password = ((PasswordProtection)protection).getPassword();
	    } else if (protection instanceof CallbackHandlerProtection) {
		CallbackHandler handler = 
		    ((CallbackHandlerProtection)protection).getCallbackHandler();
		PasswordCallback callback = 
		    new PasswordCallback("Password: ", false);
		try {
		    handler.handle(new Callback[] {callback});
		} catch (UnsupportedCallbackException e) {
		    throw new NoSuchAlgorithmException
			("Could not obtain password", e);
		}
		password = callback.getPassword();
		callback.clearPassword();
		if (password == null) {
		    throw new NoSuchAlgorithmException
			("No password provided");
		}
	    } else {
		throw new NoSuchAlgorithmException("ProtectionParameter must"
		    + " be PasswordProtection or CallbackHandlerProtection");
	    }
	    engineLoad(null, password);
	    return;
	}

	throw new UnsupportedOperationException();
    }

    /**
     * Gets a <code>KeyStore.Entry</code> for the specified alias
     * with the specified protection parameter.
     *
     * @param alias get the <code>KeyStore.Entry</code> for this alias
     * @param protParam the <code>ProtectionParameter</code>
     *		used to protect the <code>Entry</code>,
     *		which may be <code>null</code>
     *
     * @return the <code>KeyStore.Entry</code> for the specified alias,
     *		or <code>null</code> if there is no such entry
     *
     * @exception KeyStoreException if the operation failed
     * @exception NoSuchAlgorithmException if the algorithm for recovering the
     *		entry cannot be found
     * @exception UnrecoverableEntryException if the specified
     *		<code>protParam</code> were insufficient or invalid
     * @exception UnrecoverableKeyException if the entry is a 
     *          <code>PrivateKeyEntry</code> or <code>SecretKeyEntry</code>
     *          and the specified <code>protParam</code> does not contain
     *          the information needed to recover the key (e.g. wrong password)
     *
     * @since 1.5
     */
    public KeyStore.Entry engineGetEntry(String alias,
			KeyStore.ProtectionParameter protParam)
		throws KeyStoreException, NoSuchAlgorithmException,
		UnrecoverableEntryException {

	if (!engineContainsAlias(alias)) {
	    return null;
	}

	if (protParam == null) {
	    if (engineIsCertificateEntry(alias)) {
		return new KeyStore.TrustedCertificateEntry
				(engineGetCertificate(alias));
	    } else {
		throw new UnrecoverableKeyException
			("requested entry requires a password");
	    }
	}

	if (protParam instanceof KeyStore.PasswordProtection) {
	    if (engineIsCertificateEntry(alias)) {
		throw new UnsupportedOperationException
		    ("trusted certificate entries are not password-protected");
	    } else if (engineIsKeyEntry(alias)) {
		KeyStore.PasswordProtection pp =
			(KeyStore.PasswordProtection)protParam;
		char[] password = pp.getPassword();
		
		Key key = engineGetKey(alias, password);
		if (key instanceof PrivateKey) {
		    Certificate[] chain = engineGetCertificateChain(alias);
		    return new KeyStore.PrivateKeyEntry((PrivateKey)key, chain);
		} else if (key instanceof SecretKey) {
		    return new KeyStore.SecretKeyEntry((SecretKey)key);
		}
	    }
	}

	throw new UnsupportedOperationException();
    }

    /**
     * Saves a <code>KeyStore.Entry</code> under the specified alias.
     * The specified protection parameter is used to protect the
     * <code>Entry</code>.
     *
     * <p> If an entry already exists for the specified alias,
     * it is overridden.
     *
     * @param alias save the <code>KeyStore.Entry</code> under this alias
     * @param entry the <code>Entry</code> to save
     * @param protParam the <code>ProtectionParameter</code>
     *		used to protect the <code>Entry</code>,
     *		which may be <code>null</code>
     *
     * @exception KeyStoreException if this operation fails
     *
     * @since 1.5
     */
    public void engineSetEntry(String alias, KeyStore.Entry entry,
			KeyStore.ProtectionParameter protParam)
		throws KeyStoreException {

	// get password
	if (protParam != null &&
	    !(protParam instanceof KeyStore.PasswordProtection)) {
	    throw new KeyStoreException("unsupported protection parameter");
	}
	KeyStore.PasswordProtection pProtect = null;
	if (protParam != null) {
	    pProtect = (KeyStore.PasswordProtection)protParam;
	}

	// set entry
	if (entry instanceof KeyStore.TrustedCertificateEntry) {
	    if (protParam != null && pProtect.getPassword() != null) {
		// pre-1.5 style setCertificateEntry did not allow password
		throw new KeyStoreException
		    ("trusted certificate entries are not password-protected");
	    } else {
		KeyStore.TrustedCertificateEntry tce =
			(KeyStore.TrustedCertificateEntry)entry;
		engineSetCertificateEntry(alias, tce.getTrustedCertificate());
		return;
	    }
	} else if (entry instanceof KeyStore.PrivateKeyEntry) {
	    if (pProtect == null || pProtect.getPassword() == null) {
		// pre-1.5 style setKeyEntry required password
		throw new KeyStoreException
		    ("non-null password required to create PrivateKeyEntry");
	    } else {
		engineSetKeyEntry
		    (alias,
		    ((KeyStore.PrivateKeyEntry)entry).getPrivateKey(),
		    pProtect.getPassword(),
		    ((KeyStore.PrivateKeyEntry)entry).getCertificateChain());
		return;
	    }
	} else if (entry instanceof KeyStore.SecretKeyEntry) {
	    if (pProtect == null || pProtect.getPassword() == null) {
		// pre-1.5 style setKeyEntry required password
		throw new KeyStoreException
		    ("non-null password required to create SecretKeyEntry");
	    } else {
		engineSetKeyEntry
		    (alias,
		    ((KeyStore.SecretKeyEntry)entry).getSecretKey(),
		    pProtect.getPassword(),
		    (Certificate[])null);
		return;
	    }
	}

	throw new KeyStoreException
		("unsupported entry type: " + entry.getClass().getName());
    }

    /**
     * Determines if the keystore <code>Entry</code> for the specified
     * <code>alias</code> is an instance or subclass of the specified
     * <code>entryClass</code>.
     *
     * @param alias the alias name
     * @param entryClass the entry class
     *
     * @return true if the keystore <code>Entry</code> for the specified
     *		<code>alias</code> is an instance or subclass of the
     *		specified <code>entryClass</code>, false otherwise
     *
     * @since 1.5
     */
    public boolean
	engineEntryInstanceOf(String alias,
			      Class<? extends KeyStore.Entry> entryClass)
    {
	if (entryClass == KeyStore.TrustedCertificateEntry.class) {
	    return engineIsCertificateEntry(alias);
	}
	if (entryClass == KeyStore.PrivateKeyEntry.class) {
	    return engineIsKeyEntry(alias) &&
			engineGetCertificate(alias) != null;
	} 
	if (entryClass == KeyStore.SecretKeyEntry.class) {
	    return engineIsKeyEntry(alias) &&
			engineGetCertificate(alias) == null;
	}
	return false;
    }
}