de.schlichtherle.key.passwd.console.PromptingKeyProviderUI Maven / Gradle / Ivy

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TrueZIP is a Java based Virtual File System (VFS) to enable transparent, multi-threaded read/write access to archive files (ZIP, TAR etc.) as if they were directories. Archive files may be arbitrarily nested and the nesting level is only limited by heap and file system size.
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/*
 * Copyright (C) 2006-2010 Schlichtherle IT Services
 *
 * 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 de.schlichtherle.key.passwd.console;

import de.schlichtherle.key.*;

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

/**
 * A out I/O based user interface to prompt for passwords.
 * This class is thread safe.
 * 
 * @author Christian Schlichtherle
 * @version $Id$
 * @since TrueZIP 6.4
 */
public class PromptingKeyProviderUI
        implements de.schlichtherle.key.PromptingKeyProviderUI {

    private static final String CLASS_NAME
            = "de.schlichtherle.key.passwd.console.PromptingKeyProviderUI";
    protected static final ResourceBundle resources
            = ResourceBundle.getBundle(CLASS_NAME);

    /**
     * The console to use for I/O.
     * If {@code null}, the prompt methods are never called, so it's
     * safe to assume that it's not {@code null} in these methods.
     */
    protected static final Console con = System.console();

    /**
     * Used to lock out prompting by multiple threads.
     */
    private static final PromptingLock lock = new PromptingLock();

    /** The minimum acceptable length of a password. */
    private static final int MIN_PASSWD_LEN = 6;

    /**
     * The last resource ID used when prompting.
     * Initialized to the empty string.
     */
    private static String lastResourceID = "";

    public final void promptCreateKey(final PromptingKeyProvider provider) {
        synchronized (lock) {
            final String resourceID = provider.getResourceID();
            if (!resourceID.equals(lastResourceID))
                printf(resources.getString("createKey.banner"),
                        provider.getResourceID());
            lastResourceID = resourceID;

            while (true) {
                char[] newPasswd1 = readPassword(
                        resources.getString("createKey.newPasswd1"));
                if (newPasswd1 == null || newPasswd1.length <= 0)
                    return;

                char[] newPasswd2 = readPassword(
                        resources.getString("createKey.newPasswd2"));
                if (newPasswd2 == null)
                    return;

                if (!Arrays.equals(newPasswd1, newPasswd2)) {
                    printf(resources.getString("createKey.passwd.noMatch"));
                    continue;
                }

                if (newPasswd1.length < MIN_PASSWD_LEN) {
                    printf(resources.getString("createKey.passwd.tooShort"));
                    continue;
                }

                provider.setKey(newPasswd1);
                break;
            }

            promptExtraData(provider);
        }
    }

    protected void promptExtraData(PromptingKeyProvider provider)
    {
    }

    public final boolean promptUnknownOpenKey(PromptingKeyProvider provider) {
        synchronized (lock) {
            return promptOpenKey(provider, false);
        }
    }

    public final boolean promptInvalidOpenKey(PromptingKeyProvider provider) {
        synchronized (lock) {
            return promptOpenKey(provider, true);
        }
    }

    private boolean promptOpenKey(final PromptingKeyProvider provider, final boolean invalid) {
        if (invalid)
            printf(resources.getString("openKey.invalid"));

        final String resourceID = provider.getResourceID();
        if (!resourceID.equals(lastResourceID))
            printf(resources.getString("openKey.banner"),
                    provider.getResourceID());
        lastResourceID = resourceID;

        char[] passwd = readPassword(resources.getString("openKey.passwd"));
        if (passwd == null || passwd.length <= 0) {
            provider.setKey(null);
            return false;
        }

        provider.setKey(passwd);

        while (true) {
            String changeKey = readLine(resources.getString("openKey.change"));
            if (changeKey == null)
                return false;
            changeKey = changeKey.toLowerCase();
            if (changeKey.length() <= 0 || changeKey.equals(resources.getString("no")))
                return false;
            else if (changeKey.equals(resources.getString("yes")))
                return true;
        }
    }

    //
    // TrueZIP 6.4 is still Java source level 1.4, so we need these helpers
    // as a substitute for the varargs calls.
    //

    protected final Console printf(String format) {
        return con.printf(format, null);
    }

    protected final Console printf(String format, Object arg) {
        return con.printf(format, new Object[] { arg });
    }

    protected final String readLine(String format) {
        return con.readLine(format, null);
    }

    protected final String readLine(String format, Object arg) {
        return con.readLine(format, new Object[] { arg });
    }

    protected final char[] readPassword(String format) {
        return con.readPassword(format, null);
    }

    //
    // Miscellaneous.
    //

    private static class PromptingLock { }
}