CredentialItem.java

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package org.eclipse.jgit.transport;

import java.util.Arrays;

import org.eclipse.jgit.internal.JGitText;

/**
 * A credential requested from a
 * {@link org.eclipse.jgit.transport.CredentialsProvider}.
 *
 * Most users should work with the specialized subclasses:
 * <ul>
 * <li>{@link org.eclipse.jgit.transport.CredentialItem.Username} for
 * usernames</li>
 * <li>{@link org.eclipse.jgit.transport.CredentialItem.Password} for
 * passwords</li>
 * <li>{@link org.eclipse.jgit.transport.CredentialItem.StringType} for other
 * general string information</li>
 * <li>{@link org.eclipse.jgit.transport.CredentialItem.CharArrayType} for other
 * general secret information</li>
 * </ul>
 *
 * This class is not thread-safe. Applications should construct their own
 * instance for each use, as the value is held within the CredentialItem object.
 */
public abstract class CredentialItem {
    private final String promptText;

    private final boolean valueSecure;

    /**
     * Initialize a prompt.
     *
     * @param promptText
     *            prompt to display to the user alongside of the input field.
     *            Should be sufficient text to indicate what to supply for this
     *            item.
     * @param maskValue
     *            true if the value should be masked from displaying during
     *            input. This should be true for passwords and other secrets,
     *            false for names and other public data.
     */
    public CredentialItem(String promptText, boolean maskValue) {
        this.promptText = promptText;
        this.valueSecure = maskValue;
    }

    /**
     * Get prompt to display to the user.
     *
     * @return prompt to display to the user.
     */
    public String getPromptText() {
        return promptText;
    }

    /**
     * Whether the value should be masked when entered.
     *
     * @return true if the value should be masked when entered.
     */
    public boolean isValueSecure() {
        return valueSecure;
    }

    /**
     * Clear the stored value, destroying it as much as possible.
     */
    public abstract void clear();

    /**
     * An item whose value is stored as a string.
     *
     * When working with secret data, consider {@link CharArrayType} instead, as
     * the internal members of the array can be cleared, reducing the chances
     * that the password is left in memory after authentication is completed.
     */
    public static class StringType extends CredentialItem {
        private String value;

        /**
         * Initialize a prompt for a single string.
         *
         * @param promptText
         *            prompt to display to the user alongside of the input
         *            field. Should be sufficient text to indicate what to
         *            supply for this item.
         * @param maskValue
         *            true if the value should be masked from displaying during
         *            input. This should be true for passwords and other
         *            secrets, false for names and other public data.
         */
        public StringType(String promptText, boolean maskValue) {
            super(promptText, maskValue);
        }

        @Override
        public void clear() {
            value = null;
        }

        /** @return the current value */
        public String getValue() {
            return value;
        }

        /**
         *
         * @param newValue
         */
        public void setValue(String newValue) {
            value = newValue;
        }
    }

    /** An item whose value is stored as a char[] and is therefore clearable. */
    public static class CharArrayType extends CredentialItem {
        private char[] value;

        /**
         * Initialize a prompt for a secure value stored in a character array.
         *
         * @param promptText
         *            prompt to display to the user alongside of the input
         *            field. Should be sufficient text to indicate what to
         *            supply for this item.
         * @param maskValue
         *            true if the value should be masked from displaying during
         *            input. This should be true for passwords and other
         *            secrets, false for names and other public data.
         */
        public CharArrayType(String promptText, boolean maskValue) {
            super(promptText, maskValue);
        }

        /** Destroys the current value, clearing the internal array. */
        @Override
        public void clear() {
            if (value != null) {
                Arrays.fill(value, (char) 0);
                value = null;
            }
        }

        /**
         * Get the current value.
         *
         * The returned array will be cleared out when {@link #clear()} is
         * called. Callers that need the array elements to survive should delay
         * invoking {@code clear()} until the value is no longer necessary.
         *
         * @return the current value array. The actual internal array is
         *         returned, reducing the number of copies present in memory.
         */
        public char[] getValue() {
            return value;
        }

        /**
         * Set the new value, clearing the old value array.
         *
         * @param newValue
         *            if not null, the array is copied.
         */
        public void setValue(char[] newValue) {
            clear();

            if (newValue != null) {
                value = new char[newValue.length];
                System.arraycopy(newValue, 0, value, 0, newValue.length);
            }
        }

        /**
         * Set the new value, clearing the old value array.
         *
         * @param newValue
         *            the new internal array. The array is <b>NOT</b> copied.
         */
        public void setValueNoCopy(char[] newValue) {
            clear();
            value = newValue;
        }
    }

    /** An item whose value is a boolean choice, presented as Yes/No. */
    public static class YesNoType extends CredentialItem {
        private boolean value;

        /**
         * Initialize a prompt for a single boolean answer.
         *
         * @param promptText
         *            prompt to display to the user alongside of the input
         *            field. Should be sufficient text to indicate what to
         *            supply for this item.
         */
        public YesNoType(String promptText) {
            super(promptText, false);
        }

        @Override
        public void clear() {
            value = false;
        }

        /** @return the current value */
        public boolean getValue() {
            return value;
        }

        /**
         * Set the new value.
         *
         * @param newValue
         */
        public void setValue(boolean newValue) {
            value = newValue;
        }
    }

    /** An advice message presented to the user, with no response required. */
    public static class InformationalMessage extends CredentialItem {
        /**
         * Initialize an informational message.
         *
         * @param messageText
         *            message to display to the user.
         */
        public InformationalMessage(String messageText) {
            super(messageText, false);
        }

        @Override
        public void clear() {
            // Nothing to clear.
        }
    }

    /** Prompt for a username, which is not masked on input. */
    public static class Username extends StringType {
        /** Initialize a new username item, with a default username prompt. */
        public Username() {
            super(JGitText.get().credentialUsername, false);
        }
    }

    /** Prompt for a password, which is masked on input. */
    public static class Password extends CharArrayType {
        /** Initialize a new password item, with a default password prompt. */
        public Password() {
            super(JGitText.get().credentialPassword, true);
        }

        /**
         * Initialize a new password item, with given prompt.
         *
         * @param msg
         *            prompt message
         */
        public Password(String msg) {
            super(msg, true);
        }
    }
}