/*
 * Copyright (C) 2008-2010, Google Inc.
 * 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.lib.Constants.HEAD;
import static org.eclipse.jgit.transport.GitProtocolConstants.CAPABILITY_ATOMIC;
import static org.eclipse.jgit.transport.GitProtocolConstants.CAPABILITY_PUSH_OPTIONS;
import static org.eclipse.jgit.transport.GitProtocolConstants.CAPABILITY_REPORT_STATUS;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.Set;

import org.eclipse.jgit.annotations.Nullable;
import org.eclipse.jgit.errors.UnpackException;
import org.eclipse.jgit.lib.ConfigConstants;
import org.eclipse.jgit.lib.Constants;
import org.eclipse.jgit.lib.NullProgressMonitor;
import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.lib.Ref;
import org.eclipse.jgit.lib.Repository;
import org.eclipse.jgit.revwalk.RevWalk;
import org.eclipse.jgit.transport.ReceiveCommand.Result;
import org.eclipse.jgit.transport.RefAdvertiser.PacketLineOutRefAdvertiser;

/**
 * Implements the server side of a push connection, receiving objects.
 */
public class ReceivePack extends BaseReceivePack {
	/** Hook to validate the update commands before execution. */
	private PreReceiveHook preReceive;

	/** Hook to report on the commands after execution. */
	private PostReceiveHook postReceive;

	/** If {@link BasePackPushConnection#CAPABILITY_REPORT_STATUS} is enabled. */
	private boolean reportStatus;

	/** Whether the client intends to use push options. */
	private boolean usePushOptions;
	private List<String> pushOptions;

	/**
	 * Create a new pack receive for an open repository.
	 *
	 * @param into
	 *            the destination repository.
	 */
	public ReceivePack(Repository into) {
		super(into);
		preReceive = PreReceiveHook.NULL;
		postReceive = PostReceiveHook.NULL;
	}

	/**
	 * Get the repository this receive completes into.
	 *
	 * @return the repository this receive completes into.
	 */
	@Override
	public final Repository getRepository() {
		return db;
	}

	/**
	 * Get the RevWalk instance used by this connection.
	 *
	 * @return the RevWalk instance used by this connection.
	 */
	@Override
	public final RevWalk getRevWalk() {
		return walk;
	}

	/**
	 * Get refs which were advertised to the client.
	 *
	 * @return all refs which were advertised to the client, or null if
	 *         {@link #setAdvertisedRefs(Map, Set)} has not been called yet.
	 */
	@Override
	public final Map<String, Ref> getAdvertisedRefs() {
		return refs;
	}

	/**
	 * Set the refs advertised by this ReceivePack.
	 * <p>
	 * Intended to be called from a
	 * {@link org.eclipse.jgit.transport.PreReceiveHook}.
	 *
	 * @param allRefs
	 *            explicit set of references to claim as advertised by this
	 *            ReceivePack instance. This overrides any references that may
	 *            exist in the source repository. The map is passed to the
	 *            configured {@link #getRefFilter()}. If null, assumes all refs
	 *            were advertised.
	 * @param additionalHaves
	 *            explicit set of additional haves to claim as advertised. If
	 *            null, assumes the default set of additional haves from the
	 *            repository.
	 */
	@Override
	public void setAdvertisedRefs(Map<String, Ref> allRefs, Set<ObjectId> additionalHaves) {
		refs = allRefs != null ? allRefs : db.getAllRefs();
		refs = refFilter.filter(refs);
		advertisedHaves.clear();

		Ref head = refs.get(HEAD);
		if (head != null && head.isSymbolic()) {
			refs.remove(HEAD);
		}

		for (Ref ref : refs.values()) {
			if (ref.getObjectId() != null) {
				advertisedHaves.add(ref.getObjectId());
			}
		}
		if (additionalHaves != null) {
			advertisedHaves.addAll(additionalHaves);
		} else {
			advertisedHaves.addAll(db.getAdditionalHaves());
		}
	}

	/**
	 * Get the push certificate used to verify the pusher's identity.
	 * <p>
	 * Only valid after commands are read from the wire.
	 *
	 * @return the parsed certificate, or null if push certificates are disabled
	 *         or no cert was presented by the client.
	 * @since 4.1
	 */
	@Override
	public PushCertificate getPushCertificate() {
		return pushCert;
	}

	/**
	 * Set the push certificate used to verify the pusher's identity.
	 * <p>
	 * Should only be called if reconstructing an instance without going through
	 * the normal {@link #recvCommands()} flow.
	 *
	 * @param cert
	 *            the push certificate to set.
	 * @since 4.1
	 */
	@Override
	public void setPushCertificate(PushCertificate cert) {
		pushCert = cert;
	}

	/**
	 * Gets an unmodifiable view of the option strings associated with the push.
	 *
	 * @return an unmodifiable view of pushOptions, or null (if pushOptions is).
	 * @since 4.5
	 */
	@Nullable
	public List<String> getPushOptions() {
		if (isAllowPushOptions() && usePushOptions) {
			return Collections.unmodifiableList(pushOptions);
		}

		// The client doesn't support push options. Return null to
		// distinguish this from the case where the client declared support
		// for push options and sent an empty list of them.
		return null;
	}

	/**
	 * Set the push options supplied by the client.
	 * <p>
	 * Should only be called if reconstructing an instance without going through
	 * the normal {@link #recvCommands()} flow.
	 *
	 * @param options
	 *            the list of options supplied by the client. The
	 *            {@code ReceivePack} instance takes ownership of this list.
	 *            Callers are encouraged to first create a copy if the list may
	 *            be modified later.
	 * @since 4.5
	 */
	public void setPushOptions(@Nullable List<String> options) {
		usePushOptions = options != null;
		pushOptions = options;
	}

	/**
	 * Get the hook invoked before updates occur.
	 *
	 * @return the hook invoked before updates occur.
	 */
	public PreReceiveHook getPreReceiveHook() {
		return preReceive;
	}

	/**
	 * Set the hook which is invoked prior to commands being executed.
	 * <p>
	 * Only valid commands (those which have no obvious errors according to the
	 * received input and this instance's configuration) are passed into the
	 * hook. The hook may mark a command with a result of any value other than
	 * {@link org.eclipse.jgit.transport.ReceiveCommand.Result#NOT_ATTEMPTED} to
	 * block its execution.
	 * <p>
	 * The hook may be called with an empty command collection if the current
	 * set is completely invalid.
	 *
	 * @param h
	 *            the hook instance; may be null to disable the hook.
	 */
	public void setPreReceiveHook(PreReceiveHook h) {
		preReceive = h != null ? h : PreReceiveHook.NULL;
	}

	/**
	 * Get the hook invoked after updates occur.
	 *
	 * @return the hook invoked after updates occur.
	 */
	public PostReceiveHook getPostReceiveHook() {
		return postReceive;
	}

	/**
	 * Set the hook which is invoked after commands are executed.
	 * <p>
	 * Only successful commands (type is
	 * {@link org.eclipse.jgit.transport.ReceiveCommand.Result#OK}) are passed
	 * into the hook. The hook may be called with an empty command collection if
	 * the current set all resulted in an error.
	 *
	 * @param h
	 *            the hook instance; may be null to disable the hook.
	 */
	public void setPostReceiveHook(PostReceiveHook h) {
		postReceive = h != null ? h : PostReceiveHook.NULL;
	}

	/**
	 * Set whether this class will report command failures as warning messages
	 * before sending the command results.
	 *
	 * @param echo
	 *            if true this class will report command failures as warning
	 *            messages before sending the command results. This is usually
	 *            not necessary, but may help buggy Git clients that discard the
	 *            errors when all branches fail.
	 * @deprecated no widely used Git versions need this any more
	 */
	@Deprecated
	public void setEchoCommandFailures(boolean echo) {
		// No-op.
	}

	/**
	 * Execute the receive task on the socket.
	 *
	 * @param input
	 *            raw input to read client commands and pack data from. Caller
	 *            must ensure the input is buffered, otherwise read performance
	 *            may suffer.
	 * @param output
	 *            response back to the Git network client. Caller must ensure
	 *            the output is buffered, otherwise write performance may
	 *            suffer.
	 * @param messages
	 *            secondary "notice" channel to send additional messages out
	 *            through. When run over SSH this should be tied back to the
	 *            standard error channel of the command execution. For most
	 *            other network connections this should be null.
	 * @throws java.io.IOException
	 */
	public void receive(final InputStream input, final OutputStream output,
			final OutputStream messages) throws IOException {
		init(input, output, messages);
		try {
			service();
		} finally {
			try {
				close();
			} finally {
				release();
			}
		}
	}

	/** {@inheritDoc} */
	@Override
	protected void enableCapabilities() {
		reportStatus = isCapabilityEnabled(CAPABILITY_REPORT_STATUS);
		usePushOptions = isCapabilityEnabled(CAPABILITY_PUSH_OPTIONS);
		super.enableCapabilities();
	}

	@Override
	void readPostCommands(PacketLineIn in) throws IOException {
		if (usePushOptions) {
			pushOptions = new ArrayList<>(4);
			for (;;) {
				String option = in.readString();
				if (option == PacketLineIn.END) {
					break;
				}
				pushOptions.add(option);
			}
		}
	}

	private void service() throws IOException {
		if (isBiDirectionalPipe()) {
			sendAdvertisedRefs(new PacketLineOutRefAdvertiser(pckOut));
			pckOut.flush();
		} else
			getAdvertisedOrDefaultRefs();
		if (hasError())
			return;
		recvCommands();
		if (hasCommands()) {
			Throwable unpackError = null;
			if (needPack()) {
				try {
					receivePackAndCheckConnectivity();
				} catch (IOException | RuntimeException | Error err) {
					unpackError = err;
				}
			}

			try {
				if (unpackError == null) {
					boolean atomic = isCapabilityEnabled(CAPABILITY_ATOMIC);
					setAtomic(atomic);

					validateCommands();
					if (atomic && anyRejects()) {
						failPendingCommands();
					}

					preReceive.onPreReceive(
							this, filterCommands(Result.NOT_ATTEMPTED));
					if (atomic && anyRejects()) {
						failPendingCommands();
					}
					executeCommands();
				}
			} finally {
				unlockPack();
			}

			if (reportStatus) {
				sendStatusReport(true, unpackError, new Reporter() {
					@Override
					void sendString(String s) throws IOException {
						pckOut.writeString(s + "\n"); //$NON-NLS-1$
					}
				});
				pckOut.end();
			} else if (msgOut != null) {
				sendStatusReport(false, unpackError, new Reporter() {
					@Override
					void sendString(String s) throws IOException {
						msgOut.write(Constants.encode(s + "\n")); //$NON-NLS-1$
					}
				});
			}

			if (unpackError != null) {
				// we already know which exception to throw. Ignore
				// potential additional exceptions raised in postReceiveHooks
				try {
					postReceive.onPostReceive(this, filterCommands(Result.OK));
				} catch (Throwable e) {
					// empty
				}
				throw new UnpackException(unpackError);
			}
			postReceive.onPostReceive(this, filterCommands(Result.OK));
			autoGc();
		}
	}

	private void autoGc() {
		Repository repo = getRepository();
		if (!repo.getConfig().getBoolean(ConfigConstants.CONFIG_RECEIVE_SECTION,
				ConfigConstants.CONFIG_KEY_AUTOGC, true)) {
			return;
		}
		repo.autoGC(NullProgressMonitor.INSTANCE);
	}

	/** {@inheritDoc} */
	@Override
	protected String getLockMessageProcessName() {
		return "jgit receive-pack"; //$NON-NLS-1$
	}
}