FtpChannel.java

/*
 * Copyright (C) 2018, Thomas Wolf <thomas.wolf@paranor.ch> and others
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Distribution License v. 1.0 which is available at
 * https://www.eclipse.org/org/documents/edl-v10.php.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */
package org.eclipse.jgit.transport;

import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Collection;
import java.util.concurrent.TimeUnit;

/**
 * An interface providing FTP operations over a {@link RemoteSession}. All
 * operations are supposed to throw {@link FtpException} for remote file system
 * errors and other IOExceptions on connection errors.
 *
 * @since 5.2
 */
public interface FtpChannel {

    /**
     * An {@link Exception} for reporting SFTP errors.
     */
    static class FtpException extends IOException {

        private static final long serialVersionUID = 7176525179280330876L;

        public static final int OK = 0;

        public static final int EOF = 1;

        public static final int NO_SUCH_FILE = 2;

        public static final int NO_PERMISSION = 3;

        public static final int UNSPECIFIED_FAILURE = 4;

        public static final int PROTOCOL_ERROR = 5;

        public static final int UNSUPPORTED = 8;

        private final int status;

        public FtpException(String message, int status) {
            super(message);
            this.status = status;
        }

        public FtpException(String message, int status, Throwable cause) {
            super(message, cause);
            this.status = status;
        }

        public int getStatus() {
            return status;
        }
    }

    /**
     * Connects the {@link FtpChannel} to the remote end.
     *
     * @param timeout
     *            for establishing the FTP connection
     * @param unit
     *            of the {@code timeout}
     * @throws IOException
     */
    void connect(int timeout, TimeUnit unit) throws IOException;

    /**
     * Disconnects and {@link FtpChannel}.
     */
    void disconnect();

    /**
     * @return whether the {@link FtpChannel} is connected
     */
    boolean isConnected();

    /**
     * Changes the current remote directory.
     *
     * @param path
     *            target directory
     * @throws IOException
     *             if the operation could not be performed remotely
     */
    void cd(String path) throws IOException;

    /**
     * @return the current remote directory path
     * @throws IOException
     */
    String pwd() throws IOException;

    /**
     * Simplified remote directory entry.
     */
    interface DirEntry {
        String getFilename();

        long getModifiedTime();

        boolean isDirectory();
    }

    /**
     * Lists contents of a remote directory
     *
     * @param path
     *            of the directory to list
     * @return the directory entries
     * @throws IOException
     */
    Collection<DirEntry> ls(String path) throws IOException;

    /**
     * Deletes a directory on the remote file system. The directory must be
     * empty.
     *
     * @param path
     *            to delete
     * @throws IOException
     */
    void rmdir(String path) throws IOException;

    /**
     * Creates a directory on the remote file system.
     *
     * @param path
     *            to create
     * @throws IOException
     */
    void mkdir(String path) throws IOException;

    /**
     * Obtain an {@link InputStream} to read the contents of a remote file.
     *
     * @param path
     *            of the file to read
     *
     * @return the stream to read from
     * @throws IOException
     */
    InputStream get(String path) throws IOException;

    /**
     * Obtain an {@link OutputStream} to write to a remote file. If the file
     * exists already, it will be overwritten.
     *
     * @param path
     *            of the file to read
     *
     * @return the stream to read from
     * @throws IOException
     */
    OutputStream put(String path) throws IOException;

    /**
     * Deletes a file on the remote file system.
     *
     * @param path
     *            to delete
     * @throws IOException
     *             if the file does not exist or could otherwise not be deleted
     */
    void rm(String path) throws IOException;

    /**
     * Deletes a file on the remote file system. If the file does not exist, no
     * exception is thrown.
     *
     * @param path
     *            to delete
     * @throws IOException
     *             if the file exist but could not be deleted
     */
    default void delete(String path) throws IOException {
        try {
            rm(path);
        } catch (FileNotFoundException e) {
            // Ignore; it's OK if the file doesn't exist
        } catch (FtpException f) {
            if (f.getStatus() == FtpException.NO_SUCH_FILE) {
                return;
            }
            throw f;
        }
    }

    /**
     * Renames a file on the remote file system. If {@code to} exists, it is
     * replaced by {@code from}. (POSIX rename() semantics)
     *
     * @param from
     *            original name of the file
     * @param to
     *            new name of the file
     * @throws IOException
     * @see <a href=
     *      "http://pubs.opengroup.org/onlinepubs/9699919799/functions/rename.html">stdio.h:
     *      rename()</a>
     */
    void rename(String from, String to) throws IOException;

}