/*
 * Copyright (C) 2007, Dave Watson <dwatson@mimvista.com>
 * Copyright (C) 2008-2010, Google Inc.
 * Copyright (C) 2008, Marek Zawirski <marek.zawirski@gmail.com>
 * Copyright (C) 2008, Robin Rosenberg <robin.rosenberg@dewire.com>
 * Copyright (C) 2008, Shawn O. Pearce <spearce@spearce.org>
 * 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.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Collections;
import java.util.Map;
import java.util.Set;

import org.eclipse.jgit.errors.NoRemoteRepositoryException;
import org.eclipse.jgit.errors.NotSupportedException;
import org.eclipse.jgit.errors.TransportException;
import org.eclipse.jgit.internal.JGitText;
import org.eclipse.jgit.lib.Repository;
import org.eclipse.jgit.lib.RepositoryBuilder;
import org.eclipse.jgit.lib.RepositoryCache;
import org.eclipse.jgit.transport.resolver.ReceivePackFactory;
import org.eclipse.jgit.transport.resolver.UploadPackFactory;
import org.eclipse.jgit.util.FS;
import org.eclipse.jgit.util.io.MessageWriter;
import org.eclipse.jgit.util.io.StreamCopyThread;

Transport to access a local directory as though it were a remote peer.

This transport is suitable for use on the local system, where the caller has
direct read or write access to the "remote" repository.

By default this transport works by spawning a helper thread within the same
JVM, and processes the data transfer using a shared memory buffer between the
calling thread and the helper thread. This is a pure-Java implementation
which does not require forking an external process.
 However, during openFetch(), if the Transport has configured Transport.getOptionUploadPack() to be anything other than "git-upload-pack" or "git upload-pack", this
implementation will fork and execute the external process, using an operating
system pipe to transfer data.
 Similarly, during openPush(), if the Transport has configured Transport.getOptionReceivePack() to be anything other than "git-receive-pack" or "git receive-pack", this
implementation will fork and execute the external process, using an operating
system pipe to transfer data.
/**
 * Transport to access a local directory as though it were a remote peer.
 * <p>
 * This transport is suitable for use on the local system, where the caller has
 * direct read or write access to the "remote" repository.
 * <p>
 * By default this transport works by spawning a helper thread within the same
 * JVM, and processes the data transfer using a shared memory buffer between the
 * calling thread and the helper thread. This is a pure-Java implementation
 * which does not require forking an external process.
 * <p>
 * However, during {@link #openFetch()}, if the Transport has configured
 * {@link Transport#getOptionUploadPack()} to be anything other than
 * <code>"git-upload-pack"</code> or <code>"git upload-pack"</code>, this
 * implementation will fork and execute the external process, using an operating
 * system pipe to transfer data.
 * <p>
 * Similarly, during {@link #openPush()}, if the Transport has configured
 * {@link Transport#getOptionReceivePack()} to be anything other than
 * <code>"git-receive-pack"</code> or <code>"git receive-pack"</code>, this
 * implementation will fork and execute the external process, using an operating
 * system pipe to transfer data.
 */
class TransportLocal extends Transport implements PackTransport {
	static final TransportProtocol PROTO_LOCAL = new TransportProtocol() {
		@Override
		public String getName() {
			return JGitText.get().transportProtoLocal;
		}

		@Override
		public Set<String> getSchemes() {
			return Collections.singleton("file"); //$NON-NLS-1$
		}

		@Override
		public boolean canHandle(URIish uri, Repository local, String remoteName) {
			if (uri.getPath() == null
					|| uri.getPort() > 0
					|| uri.getUser() != null
					|| uri.getPass() != null
					|| uri.getHost() != null
					|| (uri.getScheme() != null && !getSchemes().contains(uri.getScheme())))
				return false;
			return true;
		}

		@Override
		public Transport open(URIish uri, Repository local, String remoteName)
				throws NoRemoteRepositoryException {
			File localPath = local.isBare() ? local.getDirectory() : local.getWorkTree();
			File path = local.getFS().resolve(localPath, uri.getPath());
			// If the reference is to a local file, C Git behavior says
			// assume this is a bundle, since repositories are directories.
			if (path.isFile())
				return new TransportBundleFile(local, uri, path);

			File gitDir = RepositoryCache.FileKey.resolve(path, local.getFS());
			if (gitDir == null)
				throw new NoRemoteRepositoryException(uri, JGitText.get().notFound);
			return new TransportLocal(local, uri, gitDir);
		}

		@Override
		public Transport open(URIish uri) throws NotSupportedException,
				TransportException {
			File path = FS.DETECTED.resolve(new File("."), uri.getPath()); //$NON-NLS-1$
			// If the reference is to a local file, C Git behavior says
			// assume this is a bundle, since repositories are directories.
			if (path.isFile())
				return new TransportBundleFile(uri, path);

			File gitDir = RepositoryCache.FileKey.resolve(path, FS.DETECTED);
			if (gitDir == null)
				throw new NoRemoteRepositoryException(uri,
						JGitText.get().notFound);
			return new TransportLocal(uri, gitDir);
		}
	};

	private final File remoteGitDir;

	TransportLocal(Repository local, URIish uri, File gitDir) {
		super(local, uri);
		remoteGitDir = gitDir;
	}

	TransportLocal(URIish uri, File gitDir) {
		super(uri);
		remoteGitDir = gitDir;
	}

	UploadPack createUploadPack(Repository dst) {
		return new UploadPack(dst);
	}

	ReceivePack createReceivePack(Repository dst) {
		return new ReceivePack(dst);
	}

	private Repository openRepo() throws TransportException {
		try {
			return new RepositoryBuilder()
					.setFS(local != null ? local.getFS() : FS.DETECTED)
					.setGitDir(remoteGitDir).build();
		} catch (IOException err) {
			throw new TransportException(uri, JGitText.get().notAGitDirectory);
		}
	}

	
{@inheritDoc} /** {@inheritDoc} */
	@Override
	public FetchConnection openFetch() throws TransportException {
		final String up = getOptionUploadPack();
		if (!"git-upload-pack".equals(up) //$NON-NLS-1$
				&& !"git upload-pack".equals(up)) //$NON-NLS-1$
			return new ForkLocalFetchConnection();

		UploadPackFactory<Void> upf = (Void req,
				Repository db) -> createUploadPack(db);
		return new InternalFetchConnection<>(this, upf, null, openRepo());
	}

	
{@inheritDoc} /** {@inheritDoc} */
	@Override
	public PushConnection openPush() throws TransportException {
		final String rp = getOptionReceivePack();
		if (!"git-receive-pack".equals(rp) //$NON-NLS-1$
				&& !"git receive-pack".equals(rp)) //$NON-NLS-1$
			return new ForkLocalPushConnection();

		ReceivePackFactory<Void> rpf = (Void req,
				Repository db) -> createReceivePack(db);
		return new InternalPushConnection<>(this, rpf, null, openRepo());
	}

	
{@inheritDoc} /** {@inheritDoc} */
	@Override
	public void close() {
		// Resources must be established per-connection.
	}

	
Spawn process
Params:
cmd – 
           command
Throws:
TransportException – 
            if any.
Returns:
a Process object./**
	 * Spawn process
	 *
	 * @param cmd
	 *            command
	 * @return a {@link java.lang.Process} object.
	 * @throws org.eclipse.jgit.errors.TransportException
	 *             if any.
	 */
	protected Process spawn(String cmd)
			throws TransportException {
		try {
			String[] args = { "." }; //$NON-NLS-1$
			ProcessBuilder proc = local.getFS().runInShell(cmd, args);
			proc.directory(remoteGitDir);

			// Remove the same variables CGit does.
			Map<String, String> env = proc.environment();
			env.remove("GIT_ALTERNATE_OBJECT_DIRECTORIES"); //$NON-NLS-1$
			env.remove("GIT_CONFIG"); //$NON-NLS-1$
			env.remove("GIT_CONFIG_PARAMETERS"); //$NON-NLS-1$
			env.remove("GIT_DIR"); //$NON-NLS-1$
			env.remove("GIT_WORK_TREE"); //$NON-NLS-1$
			env.remove("GIT_GRAFT_FILE"); //$NON-NLS-1$
			env.remove("GIT_INDEX_FILE"); //$NON-NLS-1$
			env.remove("GIT_NO_REPLACE_OBJECTS"); //$NON-NLS-1$

			return proc.start();
		} catch (IOException err) {
			throw new TransportException(uri, err.getMessage(), err);
		}
	}

	class ForkLocalFetchConnection extends BasePackFetchConnection {
		private Process uploadPack;

		private Thread errorReaderThread;

		ForkLocalFetchConnection() throws TransportException {
			super(TransportLocal.this);

			final MessageWriter msg = new MessageWriter();
			setMessageWriter(msg);

			uploadPack = spawn(getOptionUploadPack());

			final InputStream upErr = uploadPack.getErrorStream();
			errorReaderThread = new StreamCopyThread(upErr, msg.getRawStream());
			errorReaderThread.start();

			InputStream upIn = uploadPack.getInputStream();
			OutputStream upOut = uploadPack.getOutputStream();

			upIn = new BufferedInputStream(upIn);
			upOut = new BufferedOutputStream(upOut);

			init(upIn, upOut);
			readAdvertisedRefs();
		}

		@Override
		public void close() {
			super.close();

			if (uploadPack != null) {
				try {
					uploadPack.waitFor();
				} catch (InterruptedException ie) {
					// Stop waiting and return anyway.
				} finally {
					uploadPack = null;
				}
			}

			if (errorReaderThread != null) {
				try {
					errorReaderThread.join();
				} catch (InterruptedException e) {
					// Stop waiting and return anyway.
				} finally {
					errorReaderThread = null;
				}
			}
		}
	}

	class ForkLocalPushConnection extends BasePackPushConnection {
		private Process receivePack;

		private Thread errorReaderThread;

		ForkLocalPushConnection() throws TransportException {
			super(TransportLocal.this);

			final MessageWriter msg = new MessageWriter();
			setMessageWriter(msg);

			receivePack = spawn(getOptionReceivePack());

			final InputStream rpErr = receivePack.getErrorStream();
			errorReaderThread = new StreamCopyThread(rpErr, msg.getRawStream());
			errorReaderThread.start();

			InputStream rpIn = receivePack.getInputStream();
			OutputStream rpOut = receivePack.getOutputStream();

			rpIn = new BufferedInputStream(rpIn);
			rpOut = new BufferedOutputStream(rpOut);

			init(rpIn, rpOut);
			readAdvertisedRefs();
		}

		@Override
		public void close() {
			super.close();

			if (receivePack != null) {
				try {
					receivePack.waitFor();
				} catch (InterruptedException ie) {
					// Stop waiting and return anyway.
				} finally {
					receivePack = null;
				}
			}

			if (errorReaderThread != null) {
				try {
					errorReaderThread.join();
				} catch (InterruptedException e) {
					// Stop waiting and return anyway.
				} finally {
					errorReaderThread = null;
				}
			}
		}
	}
}