TransportSftp: eliminate dependency on Jsch

Introduce an FtpChannel abstraction, which can be obtained from a
RemoteSession. In JSchSession, wrap a JSch ChannelSftp as such an
FtpChannel. The JSch-specific SftpException is also mapped to a
generic FtpException. Rewrite TransportSftp to use only the new
abstraction layer.

This makes it possible to provide alternate ssh/sftp implementations.

Bug: 520927
Change-Id: I379026f7d4122f34931df909a28e73c02cd8a1da
Signed-off-by: Thomas Wolf <thomas.wolf@paranor.ch>

1 files changed, 218 insertions, 0 deletions

diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/transport/FtpChannel.java b/org.eclipse.jgit/src/org/eclipse/jgit/transport/FtpChannel.java
new file mode 100644
index 0000000000..162a1dcee5
--- /dev/null
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/transport/FtpChannel.java
@@ -0,0 +1,218 @@
+/*
+ * Copyright (C) 2018, Thomas Wolf <thomas.wolf@paranor.ch>
+ * and other copyright owners as documented in the project's IP log.
+ *
+ * This program and the accompanying materials are made available
+ * under the terms of the Eclipse Distribution License v1.0 which
+ * accompanies this distribution, is reproduced below, and is
+ * available at http://www.eclipse.org/org/documents/edl-v10.php
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or
+ * without modification, are permitted provided that the following
+ * conditions are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above
+ *   copyright notice, this list of conditions and the following
+ *   disclaimer in the documentation and/or other materials provided
+ *   with the distribution.
+ *
+ * - Neither the name of the Eclipse Foundation, Inc. nor the
+ *   names of its contributors may be used to endorse or promote
+ *   products derived from this software without specific prior
+ *   written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+ * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+package org.eclipse.jgit.transport;
+
+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
+	 */
+	void rm(String path) throws IOException;
+
+	/**
+	 * Renames a file on the remote file system.
+	 *
+	 * @param from
+	 *            original name of the file
+	 * @param to
+	 *            new name of the file
+	 * @throws IOException
+	 */
+	void rename(String from, String to) throws IOException;
+
+}