/*
    * 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 static org.eclipse.jgit.transport.GitProtocolConstants.OPTION_AGENT;
  
  import java.io.EOFException;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.OutputStream;
  import java.text.MessageFormat;
  import java.util.Arrays;
  import java.util.HashSet;
  import java.util.LinkedHashMap;
  import java.util.Set;
  
  import org.eclipse.jgit.errors.InvalidObjectIdException;
  import org.eclipse.jgit.errors.NoRemoteRepositoryException;
  import org.eclipse.jgit.errors.PackProtocolException;
  import org.eclipse.jgit.errors.RemoteRepositoryException;
  import org.eclipse.jgit.errors.TransportException;
  import org.eclipse.jgit.internal.JGitText;
  import org.eclipse.jgit.lib.ObjectId;
  import org.eclipse.jgit.lib.ObjectIdRef;
  import org.eclipse.jgit.lib.Ref;
  import org.eclipse.jgit.lib.Repository;
  import org.eclipse.jgit.util.io.InterruptTimer;
  import org.eclipse.jgit.util.io.TimeoutInputStream;
  import org.eclipse.jgit.util.io.TimeoutOutputStream;
  
  /**
   * Base helper class for pack-based operations implementations. Provides partial
   * implementation of pack-protocol - refs advertising and capabilities support,
   * and some other helper methods.
   *
   * @see BasePackFetchConnection
   * @see BasePackPushConnection
   */
  abstract class BasePackConnection extends BaseConnection {
  
  	/** The repository this transport fetches into, or pushes out of. */
  	protected final Repository local;
  
  	/** Remote repository location. */
  	protected final URIish uri;
  
  	/** A transport connected to {@link #uri}. */
  	protected final Transport transport;
  
  	/** Low-level input stream, if a timeout was configured. */
  	protected TimeoutInputStream timeoutIn;
  
  	/** Low-level output stream, if a timeout was configured. */
  	protected TimeoutOutputStream timeoutOut;
  
 	/** Timer to manage {@link #timeoutIn} and {@link #timeoutOut}. */
 	private InterruptTimer myTimer;
 
 	/** Input stream reading from the remote. */
 	protected InputStream in;
 
 	/** Output stream sending to the remote. */
 	protected OutputStream out;
 
 	/** Packet line decoder around {@link #in}. */
 	protected PacketLineIn pckIn;
 
 	/** Packet line encoder around {@link #out}. */
 	protected PacketLineOut pckOut;
 
 	/** Send {@link PacketLineOut#end()} before closing {@link #out}? */
 	protected boolean outNeedsEnd;
 
 	/** True if this is a stateless RPC connection. */
 	protected boolean statelessRPC;
 
 	/** Capability tokens advertised by the remote side. */
 	private final Set<String> remoteCapablities = new HashSet<>();
 
 	/** Extra objects the remote has, but which aren't offered as refs. */
 	protected final Set<ObjectId> additionalHaves = new HashSet<>();
 
 	BasePackConnection(PackTransport packTransport) {
 		transport = (Transport) packTransport;
 		local = transport.local;
 		uri = transport.uri;
 	}
 
 	/**
 	 * Configure this connection with the directional pipes.
 	 *
 	 * @param myIn
 	 *            input stream to receive data from the peer. Caller must ensure
 	 *            the input is buffered, otherwise read performance may suffer.
 	 * @param myOut
 	 *            output stream to transmit data to the peer. Caller must ensure
 	 *            the output is buffered, otherwise write performance may
 	 *            suffer.
 	 */
 	protected final void init(InputStream myIn, OutputStream myOut) {
 		final int timeout = transport.getTimeout();
 		if (timeout > 0) {
 			final Thread caller = Thread.currentThread();
 			if (myTimer == null) {
 				myTimer = new InterruptTimer(caller.getName() + "-Timer"); //$NON-NLS-1$
 			}
 			timeoutIn = new TimeoutInputStream(myIn, myTimer);
 			timeoutOut = new TimeoutOutputStream(myOut, myTimer);
 			timeoutIn.setTimeout(timeout * 1000);
 			timeoutOut.setTimeout(timeout * 1000);
 			myIn = timeoutIn;
 			myOut = timeoutOut;
 		}
 
 		in = myIn;
 		out = myOut;
 
 		pckIn = new PacketLineIn(in);
 		pckOut = new PacketLineOut(out);
 		outNeedsEnd = true;
 	}
 
 	/**
 	 * Reads the advertised references through the initialized stream.
 	 * <p>
 	 * Subclass implementations may call this method only after setting up the
 	 * input and output streams with {@link #init(InputStream, OutputStream)}.
 	 * <p>
 	 * If any errors occur, this connection is automatically closed by invoking
 	 * {@link #close()} and the exception is wrapped (if necessary) and thrown
 	 * as a {@link org.eclipse.jgit.errors.TransportException}.
 	 *
 	 * @throws org.eclipse.jgit.errors.TransportException
 	 *             the reference list could not be scanned.
 	 */
 	protected void readAdvertisedRefs() throws TransportException {
 		try {
 			readAdvertisedRefsImpl();
 		} catch (TransportException err) {
 			close();
 			throw err;
 		} catch (IOException | RuntimeException err) {
 			close();
 			throw new TransportException(err.getMessage(), err);
 		}
 	}
 
 	private void readAdvertisedRefsImpl() throws IOException {
 		final LinkedHashMap<String, Ref> avail = new LinkedHashMap<>();
 		for (;;) {
 			String line;
 
 			try {
 				line = pckIn.readString();
 			} catch (EOFException eof) {
 				if (avail.isEmpty())
 					throw noRepository();
 				throw eof;
 			}
 			if (PacketLineIn.isEnd(line))
 				break;
 
 			if (line.startsWith("ERR ")) { //$NON-NLS-1$
 				// This is a customized remote service error.
 				// Users should be informed about it.
 				throw new RemoteRepositoryException(uri, line.substring(4));
 			}
 
 			if (avail.isEmpty()) {
 				final int nul = line.indexOf('\0');
 				if (nul >= 0) {
 					// The first line (if any) may contain "hidden"
 					// capability values after a NUL byte.
 					remoteCapablities.addAll(
 							Arrays.asList(line.substring(nul + 1).split(" "))); //$NON-NLS-1$
 					line = line.substring(0, nul);
 				}
 			}
 
 			// Expecting to get a line in the form "sha1 refname"
 			if (line.length() < 41 || line.charAt(40) != ' ') {
 				throw invalidRefAdvertisementLine(line);
 			}
 			String name = line.substring(41, line.length());
 			if (avail.isEmpty() && name.equals("capabilities^{}")) { //$NON-NLS-1$
 				// special line from git-receive-pack to show
 				// capabilities when there are no refs to advertise
 				continue;
 			}
 
 			final ObjectId id;
 			try {
 				id  = ObjectId.fromString(line.substring(0, 40));
 			} catch (InvalidObjectIdException e) {
 				throw invalidRefAdvertisementLine(line);
 			}
 			if (name.equals(".have")) { //$NON-NLS-1$
 				additionalHaves.add(id);
 			} else if (name.endsWith("^{}")) { //$NON-NLS-1$
 				name = name.substring(0, name.length() - 3);
 				final Ref prior = avail.get(name);
 				if (prior == null)
 					throw new PackProtocolException(uri, MessageFormat.format(
 							JGitText.get().advertisementCameBefore, name, name));
 
 				if (prior.getPeeledObjectId() != null)
 					throw duplicateAdvertisement(name + "^{}"); //$NON-NLS-1$
 
 				avail.put(name, new ObjectIdRef.PeeledTag(
 						Ref.Storage.NETWORK, name, prior.getObjectId(), id));
 			} else {
 				final Ref prior = avail.put(name, new ObjectIdRef.PeeledNonTag(
 						Ref.Storage.NETWORK, name, id));
 				if (prior != null)
 					throw duplicateAdvertisement(name);
 			}
 		}
 		available(avail);
 	}
 
 	/**
 	 * Create an exception to indicate problems finding a remote repository. The
 	 * caller is expected to throw the returned exception.
 	 *
 	 * Subclasses may override this method to provide better diagnostics.
 	 *
 	 * @return a TransportException saying a repository cannot be found and
 	 *         possibly why.
 	 */
 	protected TransportException noRepository() {
 		return new NoRemoteRepositoryException(uri, JGitText.get().notFound);
 	}
 
 	/**
 	 * Whether this option is supported
 	 *
 	 * @param option
 	 *            option string
 	 * @return whether this option is supported
 	 */
 	protected boolean isCapableOf(String option) {
 		return remoteCapablities.contains(option);
 	}
 
 	/**
 	 * Request capability
 	 *
 	 * @param b
 	 *            buffer
 	 * @param option
 	 *            option we want
 	 * @return {@code true} if the requested option is supported
 	 */
 	protected boolean wantCapability(StringBuilder b, String option) {
 		if (!isCapableOf(option))
 			return false;
 		b.append(' ');
 		b.append(option);
 		return true;
 	}
 
 	/**
 	 * Add user agent capability
 	 *
 	 * @param b
 	 *            a {@link java.lang.StringBuilder} object.
 	 */
 	protected void addUserAgentCapability(StringBuilder b) {
 		String a = UserAgent.get();
 		if (a != null && UserAgent.hasAgent(remoteCapablities)) {
 			b.append(' ').append(OPTION_AGENT).append('=').append(a);
 		}
 	}
 
 	/** {@inheritDoc} */
 	@Override
 	public String getPeerUserAgent() {
 		return UserAgent.getAgent(remoteCapablities, super.getPeerUserAgent());
 	}
 
 	private PackProtocolException duplicateAdvertisement(String name) {
 		return new PackProtocolException(uri, MessageFormat.format(JGitText.get().duplicateAdvertisementsOf, name));
 	}
 
 	private PackProtocolException invalidRefAdvertisementLine(String line) {
 		return new PackProtocolException(uri, MessageFormat.format(JGitText.get().invalidRefAdvertisementLine, line));
 	}
 
 	/** {@inheritDoc} */
 	@Override
 	public void close() {
 		if (out != null) {
 			try {
 				if (outNeedsEnd) {
 					outNeedsEnd = false;
 					pckOut.end();
 				}
 				out.close();
 			} catch (IOException err) {
 				// Ignore any close errors.
 			} finally {
 				out = null;
 				pckOut = null;
 			}
 		}
 
 		if (in != null) {
 			try {
 				in.close();
 			} catch (IOException err) {
 				// Ignore any close errors.
 			} finally {
 				in = null;
 				pckIn = null;
 			}
 		}
 
 		if (myTimer != null) {
 			try {
 				myTimer.terminate();
 			} finally {
 				myTimer = null;
 				timeoutIn = null;
 				timeoutOut = null;
 			}
 		}
 	}
 
 	/**
 	 * Tell the peer we are disconnecting, if it cares to know.
 	 */
 	protected void endOut() {
 		if (outNeedsEnd && out != null) {
 			try {
 				outNeedsEnd = false;
 				pckOut.end();
 			} catch (IOException e) {
 				try {
 					out.close();
 				} catch (IOException err) {
 					// Ignore any close errors.
 				} finally {
 					out = null;
 					pckOut = null;
 				}
 			}
 		}
 	}
 }