/*
 * Copyright (C) 2008, 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;
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 * 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
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 */

package org.eclipse.jgit.transport;

import static org.eclipse.jgit.transport.ReceiveCommand.Result.NOT_ATTEMPTED;
import static org.eclipse.jgit.transport.ReceiveCommand.Result.REJECTED_OTHER_REASON;

import java.io.IOException;
import java.text.MessageFormat;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;

import org.eclipse.jgit.annotations.NonNull;
import org.eclipse.jgit.annotations.Nullable;
import org.eclipse.jgit.internal.JGitText;
import org.eclipse.jgit.lib.AnyObjectId;
import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.lib.Ref;
import org.eclipse.jgit.lib.RefUpdate;
import org.eclipse.jgit.revwalk.RevCommit;
import org.eclipse.jgit.revwalk.RevObject;
import org.eclipse.jgit.revwalk.RevWalk;

A command being processed by BaseReceivePack. 
 This command instance roughly translates to the server side representation of the RemoteRefUpdate created by the client. /**
 * A command being processed by
 * {@link org.eclipse.jgit.transport.BaseReceivePack}.
 * <p>
 * This command instance roughly translates to the server side representation of
 * the {@link org.eclipse.jgit.transport.RemoteRefUpdate} created by the client.
 */
public class ReceiveCommand {
	
Type of operation requested. /** Type of operation requested. */
	public static enum Type {
		
Create a new ref; the ref must not already exist. /** Create a new ref; the ref must not already exist. */
		CREATE,

		
Update an existing ref with a fast-forward update.

During a fast-forward update no changes will be lost; only new
commits are inserted into the ref.
/**
		 * Update an existing ref with a fast-forward update.
		 * <p>
		 * During a fast-forward update no changes will be lost; only new
		 * commits are inserted into the ref.
		 */
		UPDATE,

		
Update an existing ref by potentially discarding objects.

The current value of the ref is not fully reachable from the new
value of the ref, so a successful command may result in one or more
objects becoming unreachable.
/**
		 * Update an existing ref by potentially discarding objects.
		 * <p>
		 * The current value of the ref is not fully reachable from the new
		 * value of the ref, so a successful command may result in one or more
		 * objects becoming unreachable.
		 */
		UPDATE_NONFASTFORWARD,

		
Delete an existing ref; the ref should already exist. /** Delete an existing ref; the ref should already exist. */
		DELETE;
	}

	
Result of the update command. /** Result of the update command. */
	public static enum Result {
		
The command has not yet been attempted by the server. /** The command has not yet been attempted by the server. */
		NOT_ATTEMPTED,

		
The server is configured to deny creation of this ref. /** The server is configured to deny creation of this ref. */
		REJECTED_NOCREATE,

		
The server is configured to deny deletion of this ref. /** The server is configured to deny deletion of this ref. */
		REJECTED_NODELETE,

		
The update is a non-fast-forward update and isn't permitted. /** The update is a non-fast-forward update and isn't permitted. */
		REJECTED_NONFASTFORWARD,

		
The update affects HEAD and cannot be permitted. /** The update affects <code>HEAD</code> and cannot be permitted. */
		REJECTED_CURRENT_BRANCH,

		
One or more objects aren't in the repository.

This is severe indication of either repository corruption on the
server side, or a bug in the client wherein the client did not supply
all required objects during the pack transfer.
/**
		 * One or more objects aren't in the repository.
		 * <p>
		 * This is severe indication of either repository corruption on the
		 * server side, or a bug in the client wherein the client did not supply
		 * all required objects during the pack transfer.
		 */
		REJECTED_MISSING_OBJECT,

		
Other failure; see ReceiveCommand.getMessage(). /** Other failure; see {@link ReceiveCommand#getMessage()}. */
		REJECTED_OTHER_REASON,

		
The ref could not be locked and updated atomically; try again. /** The ref could not be locked and updated atomically; try again. */
		LOCK_FAILURE,

		
The change was completed successfully. /** The change was completed successfully. */
		OK;
	}

	
Filter a collection of commands according to result.
Params:
in – 
           commands to filter.
want – 
           desired status to filter by.
Returns:
a copy of the command list containing only those commands with
        the desired status.
Since:
4.2/**
	 * Filter a collection of commands according to result.
	 *
	 * @param in
	 *            commands to filter.
	 * @param want
	 *            desired status to filter by.
	 * @return a copy of the command list containing only those commands with
	 *         the desired status.
	 * @since 4.2
	 */
	public static List<ReceiveCommand> filter(Iterable<ReceiveCommand> in,
			Result want) {
		List<ReceiveCommand> r;
		if (in instanceof Collection)
			r = new ArrayList<>(((Collection<?>) in).size());
		else
			r = new ArrayList<>();
		for (ReceiveCommand cmd : in) {
			if (cmd.getResult() == want)
				r.add(cmd);
		}
		return r;
	}

	
Filter a list of commands according to result.
Params:
commands – 
           commands to filter.
want – 
           desired status to filter by.
Returns:
a copy of the command list containing only those commands with
        the desired status.
Since:
2.0/**
	 * Filter a list of commands according to result.
	 *
	 * @param commands
	 *            commands to filter.
	 * @param want
	 *            desired status to filter by.
	 * @return a copy of the command list containing only those commands with
	 *         the desired status.
	 * @since 2.0
	 */
	public static List<ReceiveCommand> filter(List<ReceiveCommand> commands,
			Result want) {
		return filter((Iterable<ReceiveCommand>) commands, want);
	}

	
Set unprocessed commands as failed due to transaction aborted.
 If a command is still Result.NOT_ATTEMPTED it will be set to Result.REJECTED_OTHER_REASON. 
Params:
commands – 
           commands to mark as failed.
Since:
4.2/**
	 * Set unprocessed commands as failed due to transaction aborted.
	 * <p>
	 * If a command is still
	 * {@link org.eclipse.jgit.transport.ReceiveCommand.Result#NOT_ATTEMPTED} it
	 * will be set to
	 * {@link org.eclipse.jgit.transport.ReceiveCommand.Result#REJECTED_OTHER_REASON}.
	 *
	 * @param commands
	 *            commands to mark as failed.
	 * @since 4.2
	 */
	public static void abort(Iterable<ReceiveCommand> commands) {
		for (ReceiveCommand c : commands) {
			if (c.getResult() == NOT_ATTEMPTED) {
				c.setResult(REJECTED_OTHER_REASON,
						JGitText.get().transactionAborted);
			}
		}
	}

	
Check whether a command failed due to transaction aborted.
Params:
cmd – 
           command.
Returns:
whether the command failed due to transaction aborted, as in abort(Iterable<ReceiveCommand>).
Since:
4.9/**
	 * Check whether a command failed due to transaction aborted.
	 *
	 * @param cmd
	 *            command.
	 * @return whether the command failed due to transaction aborted, as in
	 *         {@link #abort(Iterable)}.
	 * @since 4.9
	 */
	public static boolean isTransactionAborted(ReceiveCommand cmd) {
		return cmd.getResult() == REJECTED_OTHER_REASON
				&& cmd.getMessage().equals(JGitText.get().transactionAborted);
	}

	
Create a command to switch a reference from object to symbolic.
Params:
oldId –  expected oldId. May be zeroId to create.
newTarget –  new target; must begin with "refs/".
name – 
           name of the reference to make symbolic.
Returns:
command instance.
Since:
4.10/**
	 * Create a command to switch a reference from object to symbolic.
	 *
	 * @param oldId
	 *            expected oldId. May be {@code zeroId} to create.
	 * @param newTarget
	 *            new target; must begin with {@code "refs/"}.
	 * @param name
	 *            name of the reference to make symbolic.
	 * @return command instance.
	 * @since 4.10
	 */
	public static ReceiveCommand link(@NonNull ObjectId oldId,
			@NonNull String newTarget, @NonNull String name) {
		return new ReceiveCommand(oldId, newTarget, name);
	}

	
Create a command to switch a symbolic reference's target.
Params:
oldTarget – 
           expected old target. May be null to create.
newTarget –  new target; must begin with "refs/".
name – 
           name of the reference to make symbolic.
Returns:
command instance.
Since:
4.10/**
	 * Create a command to switch a symbolic reference's target.
	 *
	 * @param oldTarget
	 *            expected old target. May be null to create.
	 * @param newTarget
	 *            new target; must begin with {@code "refs/"}.
	 * @param name
	 *            name of the reference to make symbolic.
	 * @return command instance.
	 * @since 4.10
	 */
	public static ReceiveCommand link(@Nullable String oldTarget,
			@NonNull String newTarget, @NonNull String name) {
		return new ReceiveCommand(oldTarget, newTarget, name);
	}

	
Create a command to switch a reference from symbolic to object.
Params:
oldTarget – 
           expected old target.
newId –  new object identifier. May be zeroId() to delete.
name – 
           name of the reference to convert from symbolic.
Returns:
command instance.
Since:
4.10/**
	 * Create a command to switch a reference from symbolic to object.
	 *
	 * @param oldTarget
	 *            expected old target.
	 * @param newId
	 *            new object identifier. May be {@code zeroId()} to delete.
	 * @param name
	 *            name of the reference to convert from symbolic.
	 * @return command instance.
	 * @since 4.10
	 */
	public static ReceiveCommand unlink(@NonNull String oldTarget,
			@NonNull ObjectId newId, @NonNull String name) {
		return new ReceiveCommand(oldTarget, newId, name);
	}

	private final ObjectId oldId;

	private final String oldSymref;

	private final ObjectId newId;

	private final String newSymref;

	private final String name;

	private Type type;

	private boolean typeIsCorrect;

	private Ref ref;

	private Result status = Result.NOT_ATTEMPTED;

	private String message;

	private boolean customRefLog;

	private String refLogMessage;

	private boolean refLogIncludeResult;

	private Boolean forceRefLog;

	
Create a new command for BaseReceivePack. 
Params:
oldId –  the expected old object id; must not be null. Use ObjectId.zeroId() to indicate a ref creation.
newId –  the new object id; must not be null. Use ObjectId.zeroId() to indicate a ref deletion.
name – 
           name of the ref being affected./**
	 * Create a new command for
	 * {@link org.eclipse.jgit.transport.BaseReceivePack}.
	 *
	 * @param oldId
	 *            the expected old object id; must not be null. Use
	 *            {@link org.eclipse.jgit.lib.ObjectId#zeroId()} to indicate a
	 *            ref creation.
	 * @param newId
	 *            the new object id; must not be null. Use
	 *            {@link org.eclipse.jgit.lib.ObjectId#zeroId()} to indicate a
	 *            ref deletion.
	 * @param name
	 *            name of the ref being affected.
	 */
	public ReceiveCommand(final ObjectId oldId, final ObjectId newId,
			final String name) {
		if (oldId == null) {
			throw new IllegalArgumentException(
					JGitText.get().oldIdMustNotBeNull);
		}
		if (newId == null) {
			throw new IllegalArgumentException(
					JGitText.get().newIdMustNotBeNull);
		}
		if (name == null || name.isEmpty()) {
			throw new IllegalArgumentException(
					JGitText.get().nameMustNotBeNullOrEmpty);
		}
		this.oldId = oldId;
		this.oldSymref = null;
		this.newId = newId;
		this.newSymref = null;
		this.name = name;

		type = Type.UPDATE;
		if (ObjectId.zeroId().equals(oldId)) {
			type = Type.CREATE;
		}
		if (ObjectId.zeroId().equals(newId)) {
			type = Type.DELETE;
		}
	}

	
Create a new command for BaseReceivePack. 
Params:
oldId –  the old object id; must not be null. Use ObjectId.zeroId() to indicate a ref creation.
newId –  the new object id; must not be null. Use ObjectId.zeroId() to indicate a ref deletion.
name – 
           name of the ref being affected.
type –  type of the command. Must be Type.CREATE if 
           oldId is zero, or Type.DELETE if newId is zero.
Since:
2.0/**
	 * Create a new command for
	 * {@link org.eclipse.jgit.transport.BaseReceivePack}.
	 *
	 * @param oldId
	 *            the old object id; must not be null. Use
	 *            {@link org.eclipse.jgit.lib.ObjectId#zeroId()} to indicate a
	 *            ref creation.
	 * @param newId
	 *            the new object id; must not be null. Use
	 *            {@link org.eclipse.jgit.lib.ObjectId#zeroId()} to indicate a
	 *            ref deletion.
	 * @param name
	 *            name of the ref being affected.
	 * @param type
	 *            type of the command. Must be
	 *            {@link org.eclipse.jgit.transport.ReceiveCommand.Type#CREATE}
	 *            if {@code
	 *            oldId} is zero, or
	 *            {@link org.eclipse.jgit.transport.ReceiveCommand.Type#DELETE}
	 *            if {@code newId} is zero.
	 * @since 2.0
	 */
	public ReceiveCommand(final ObjectId oldId, final ObjectId newId,
			final String name, final Type type) {
		if (oldId == null) {
			throw new IllegalArgumentException(
					JGitText.get().oldIdMustNotBeNull);
		}
		if (newId == null) {
			throw new IllegalArgumentException(
					JGitText.get().newIdMustNotBeNull);
		}
		if (name == null || name.isEmpty()) {
			throw new IllegalArgumentException(
					JGitText.get().nameMustNotBeNullOrEmpty);
		}
		this.oldId = oldId;
		this.oldSymref = null;
		this.newId = newId;
		this.newSymref = null;
		this.name = name;
		switch (type) {
		case CREATE:
			if (!ObjectId.zeroId().equals(oldId)) {
				throw new IllegalArgumentException(
						JGitText.get().createRequiresZeroOldId);
			}
			break;
		case DELETE:
			if (!ObjectId.zeroId().equals(newId)) {
				throw new IllegalArgumentException(
						JGitText.get().deleteRequiresZeroNewId);
			}
			break;
		case UPDATE:
		case UPDATE_NONFASTFORWARD:
			if (ObjectId.zeroId().equals(newId)
					|| ObjectId.zeroId().equals(oldId)) {
				throw new IllegalArgumentException(
						JGitText.get().updateRequiresOldIdAndNewId);
			}
			break;
		default:
			throw new IllegalStateException(
					JGitText.get().enumValueNotSupported0);
		}
		this.type = type;
	}

	
Create a command to switch a reference from object to symbolic.
Params:
oldId –  the old object id; must not be null. Use ObjectId.zeroId() to indicate a ref creation.
newSymref –  new target, must begin with "refs/". Use null to indicate a ref deletion.
name – 
           name of the reference to make symbolic.
Since:
4.10/**
	 * Create a command to switch a reference from object to symbolic.
	 *
	 * @param oldId
	 *            the old object id; must not be null. Use
	 *            {@link ObjectId#zeroId()} to indicate a ref creation.
	 * @param newSymref
	 *            new target, must begin with {@code "refs/"}. Use {@code null}
	 *            to indicate a ref deletion.
	 * @param name
	 *            name of the reference to make symbolic.
	 * @since 4.10
	 */
	private ReceiveCommand(ObjectId oldId, String newSymref, String name) {
		if (oldId == null) {
			throw new IllegalArgumentException(
					JGitText.get().oldIdMustNotBeNull);
		}
		if (name == null || name.isEmpty()) {
			throw new IllegalArgumentException(
					JGitText.get().nameMustNotBeNullOrEmpty);
		}
		this.oldId = oldId;
		this.oldSymref = null;
		this.newId = ObjectId.zeroId();
		this.newSymref = newSymref;
		this.name = name;
		if (AnyObjectId.isEqual(ObjectId.zeroId(), oldId)) {
			type = Type.CREATE;
		} else if (newSymref != null) {
			type = Type.UPDATE;
		} else {
			type = Type.DELETE;
		}
		typeIsCorrect = true;
	}

	
Create a command to switch a reference from symbolic to object.
Params:
oldSymref –  expected old target. Use null to indicate a ref creation.
newId –  the new object id; must not be null. Use ObjectId.zeroId() to indicate a ref deletion.
name – 
           name of the reference to convert from symbolic.
Since:
4.10/**
	 * Create a command to switch a reference from symbolic to object.
	 *
	 * @param oldSymref
	 *            expected old target. Use {@code null} to indicate a ref
	 *            creation.
	 * @param newId
	 *            the new object id; must not be null. Use
	 *            {@link ObjectId#zeroId()} to indicate a ref deletion.
	 * @param name
	 *            name of the reference to convert from symbolic.
	 * @since 4.10
	 */
	private ReceiveCommand(String oldSymref, ObjectId newId, String name) {
		if (newId == null) {
			throw new IllegalArgumentException(
					JGitText.get().newIdMustNotBeNull);
		}
		if (name == null || name.isEmpty()) {
			throw new IllegalArgumentException(
					JGitText.get().nameMustNotBeNullOrEmpty);
		}
		this.oldId = ObjectId.zeroId();
		this.oldSymref = oldSymref;
		this.newId = newId;
		this.newSymref = null;
		this.name = name;
		if (oldSymref == null) {
			type = Type.CREATE;
		} else if (!AnyObjectId.isEqual(ObjectId.zeroId(), newId)) {
			type = Type.UPDATE;
		} else {
			type = Type.DELETE;
		}
		typeIsCorrect = true;
	}

	
Create a command to switch a symbolic reference's target.
Params:
oldTarget –  expected old target. Use null to indicate a ref creation.
newTarget –  new target. Use null to indicate a ref deletion.
name – 
           name of the reference to make symbolic.
Since:
4.10/**
	 * Create a command to switch a symbolic reference's target.
	 *
	 * @param oldTarget
	 *            expected old target. Use {@code null} to indicate a ref
	 *            creation.
	 * @param newTarget
	 *            new target. Use {@code null} to indicate a ref deletion.
	 * @param name
	 *            name of the reference to make symbolic.
	 * @since 4.10
	 */
	private ReceiveCommand(@Nullable String oldTarget, String newTarget, String name) {
		if (name == null || name.isEmpty()) {
			throw new IllegalArgumentException(
					JGitText.get().nameMustNotBeNullOrEmpty);
		}
		this.oldId = ObjectId.zeroId();
		this.oldSymref = oldTarget;
		this.newId = ObjectId.zeroId();
		this.newSymref = newTarget;
		this.name = name;
		if (oldTarget == null) {
			if (newTarget == null) {
				throw new IllegalArgumentException(
						JGitText.get().bothRefTargetsMustNotBeNull);
			}
			type = Type.CREATE;
		} else if (newTarget != null) {
			type = Type.UPDATE;
		} else {
			type = Type.DELETE;
		}
		typeIsCorrect = true;
	}

	
Get the old value the client thinks the ref has.
Returns:
the old value the client thinks the ref has./**
	 * Get the old value the client thinks the ref has.
	 *
	 * @return the old value the client thinks the ref has.
	 */
	public ObjectId getOldId() {
		return oldId;
	}

	
Get expected old target for a symbolic reference.
Returns:
expected old target for a symbolic reference.
Since:
4.10/**
	 * Get expected old target for a symbolic reference.
	 *
	 * @return expected old target for a symbolic reference.
	 * @since 4.10
	 */
	@Nullable
	public String getOldSymref() {
		return oldSymref;
	}

	
Get the requested new value for this ref.
Returns:
the requested new value for this ref./**
	 * Get the requested new value for this ref.
	 *
	 * @return the requested new value for this ref.
	 */
	public ObjectId getNewId() {
		return newId;
	}

	
Get requested new target for a symbolic reference.
Returns:
requested new target for a symbolic reference.
Since:
4.10/**
	 * Get requested new target for a symbolic reference.
	 *
	 * @return requested new target for a symbolic reference.
	 * @since 4.10
	 */
	@Nullable
	public String getNewSymref() {
		return newSymref;
	}

	
Get the name of the ref being updated.
Returns:
the name of the ref being updated./**
	 * Get the name of the ref being updated.
	 *
	 * @return the name of the ref being updated.
	 */
	public String getRefName() {
		return name;
	}

	
Get the type of this command; see Type. 
Returns:
the type of this command; see Type./**
	 * Get the type of this command; see {@link Type}.
	 *
	 * @return the type of this command; see {@link Type}.
	 */
	public Type getType() {
		return type;
	}

	
Get the ref, if this was advertised by the connection.
Returns:
the ref, if this was advertised by the connection./**
	 * Get the ref, if this was advertised by the connection.
	 *
	 * @return the ref, if this was advertised by the connection.
	 */
	public Ref getRef() {
		return ref;
	}

	
Get the current status code of this command.
Returns:
the current status code of this command./**
	 * Get the current status code of this command.
	 *
	 * @return the current status code of this command.
	 */
	public Result getResult() {
		return status;
	}

	
Get the message associated with a failure status.
Returns:
the message associated with a failure status./**
	 * Get the message associated with a failure status.
	 *
	 * @return the message associated with a failure status.
	 */
	public String getMessage() {
		return message;
	}

	
Set the message to include in the reflog.
 Overrides the default set by setRefLogMessage on any containing BatchRefUpdate. 
Params:
msg – 
           the message to describe this change. If null and appendStatus is
           false, the reflog will not be updated.
appendStatus – 
           true if the status of the ref change (fast-forward or
           forced-update) should be appended to the user supplied message.
Since:
4.9/**
	 * Set the message to include in the reflog.
	 * <p>
	 * Overrides the default set by {@code setRefLogMessage} on any containing
	 * {@link org.eclipse.jgit.lib.BatchRefUpdate}.
	 *
	 * @param msg
	 *            the message to describe this change. If null and appendStatus is
	 *            false, the reflog will not be updated.
	 * @param appendStatus
	 *            true if the status of the ref change (fast-forward or
	 *            forced-update) should be appended to the user supplied message.
	 * @since 4.9
	 */
	public void setRefLogMessage(String msg, boolean appendStatus) {
		customRefLog = true;
		if (msg == null && !appendStatus) {
			disableRefLog();
		} else if (msg == null && appendStatus) {
			refLogMessage = ""; //$NON-NLS-1$
			refLogIncludeResult = true;
		} else {
			refLogMessage = msg;
			refLogIncludeResult = appendStatus;
		}
	}

	
Don't record this update in the ref's associated reflog.
 Equivalent to setRefLogMessage(null, false). 
Since:
4.9/**
	 * Don't record this update in the ref's associated reflog.
	 * <p>
	 * Equivalent to {@code setRefLogMessage(null, false)}.
	 *
	 * @since 4.9
	 */
	public void disableRefLog() {
		customRefLog = true;
		refLogMessage = null;
		refLogIncludeResult = false;
	}

	
Force writing a reflog for the updated ref.
Params:
force – whether to force.
Since:
4.9/**
	 * Force writing a reflog for the updated ref.
	 *
	 * @param force whether to force.
	 * @since 4.9
	 */
	public void setForceRefLog(boolean force) {
		forceRefLog = Boolean.valueOf(force);
	}

	
Check whether this command has a custom reflog message setting that should override defaults in any containing BatchRefUpdate. 
 Does not take into account whether #setForceRefLog(boolean) has been called. 
Returns:
whether a custom reflog is set.
Since:
4.9/**
	 * Check whether this command has a custom reflog message setting that should
	 * override defaults in any containing
	 * {@link org.eclipse.jgit.lib.BatchRefUpdate}.
	 * <p>
	 * Does not take into account whether {@code #setForceRefLog(boolean)} has
	 * been called.
	 *
	 * @return whether a custom reflog is set.
	 * @since 4.9
	 */
	public boolean hasCustomRefLog() {
		return customRefLog;
	}

	
Check whether log has been disabled by disableRefLog(). 
Returns:
true if disabled.
Since:
4.9/**
	 * Check whether log has been disabled by {@link #disableRefLog()}.
	 *
	 * @return true if disabled.
	 * @since 4.9
	 */
	public boolean isRefLogDisabled() {
		return refLogMessage == null;
	}

	
Get the message to include in the reflog.
Returns:
message the caller wants to include in the reflog; null if the
        update should not be logged.
Since:
4.9/**
	 * Get the message to include in the reflog.
	 *
	 * @return message the caller wants to include in the reflog; null if the
	 *         update should not be logged.
	 * @since 4.9
	 */
	@Nullable
	public String getRefLogMessage() {
		return refLogMessage;
	}

	
Check whether the reflog message should include the result of the update,
such as fast-forward or force-update.
Returns:
true if the message should include the result.
Since:
4.9/**
	 * Check whether the reflog message should include the result of the update,
	 * such as fast-forward or force-update.
	 *
	 * @return true if the message should include the result.
	 * @since 4.9
	 */
	public boolean isRefLogIncludingResult() {
		return refLogIncludeResult;
	}

	
Check whether the reflog should be written regardless of repo defaults.
Returns:
whether force writing is enabled; null if #setForceRefLog(boolean) was never called.
Since:
4.9/**
	 * Check whether the reflog should be written regardless of repo defaults.
	 *
	 * @return whether force writing is enabled; {@code null} if
	 *         {@code #setForceRefLog(boolean)} was never called.
	 * @since 4.9
	 */
	@Nullable
	public Boolean isForceRefLog() {
		return forceRefLog;
	}

	
Set the status of this command.
Params:
s – 
           the new status code for this command./**
	 * Set the status of this command.
	 *
	 * @param s
	 *            the new status code for this command.
	 */
	public void setResult(Result s) {
		setResult(s, null);
	}

	
Set the status of this command.
Params:
s – 
           new status code for this command.
m – 
           optional message explaining the new status./**
	 * Set the status of this command.
	 *
	 * @param s
	 *            new status code for this command.
	 * @param m
	 *            optional message explaining the new status.
	 */
	public void setResult(Result s, String m) {
		status = s;
		message = m;
	}

	
Update the type of this command by checking for fast-forward.
 If the command's current type is UPDATE, a merge test will be performed using the supplied RevWalk to determine if getOldId() is fully merged into getNewId(). If some commits are not merged the update type is changed to Type.UPDATE_NONFASTFORWARD. 
Params:
walk – 
           an instance to perform the merge test with. The caller must
           allocate and release this object.
Throws:
IOException – 
            either oldId or newId is not accessible in the repository
            used by the RevWalk. This usually indicates data corruption,
            and the command cannot be processed./**
	 * Update the type of this command by checking for fast-forward.
	 * <p>
	 * If the command's current type is UPDATE, a merge test will be performed
	 * using the supplied RevWalk to determine if {@link #getOldId()} is fully
	 * merged into {@link #getNewId()}. If some commits are not merged the
	 * update type is changed to
	 * {@link org.eclipse.jgit.transport.ReceiveCommand.Type#UPDATE_NONFASTFORWARD}.
	 *
	 * @param walk
	 *            an instance to perform the merge test with. The caller must
	 *            allocate and release this object.
	 * @throws java.io.IOException
	 *             either oldId or newId is not accessible in the repository
	 *             used by the RevWalk. This usually indicates data corruption,
	 *             and the command cannot be processed.
	 */
	public void updateType(RevWalk walk) throws IOException {
		if (typeIsCorrect)
			return;
		if (type == Type.UPDATE && !AnyObjectId.isEqual(oldId, newId)) {
			RevObject o = walk.parseAny(oldId);
			RevObject n = walk.parseAny(newId);
			if (!(o instanceof RevCommit)
					|| !(n instanceof RevCommit)
					|| !walk.isMergedInto((RevCommit) o, (RevCommit) n))
				setType(Type.UPDATE_NONFASTFORWARD);
		}
		typeIsCorrect = true;
	}

	
Execute this command during a receive-pack session.

Sets the status of the command as a side effect.
Params:
rp – 
           receive-pack session.
Since:
2.0/**
	 * Execute this command during a receive-pack session.
	 * <p>
	 * Sets the status of the command as a side effect.
	 *
	 * @param rp
	 *            receive-pack session.
	 * @since 2.0
	 */
	public void execute(BaseReceivePack rp) {
		try {
			String expTarget = getOldSymref();
			boolean detach = getNewSymref() != null
					|| (type == Type.DELETE && expTarget != null);
			RefUpdate ru = rp.getRepository().updateRef(getRefName(), detach);
			if (expTarget != null) {
				if (!ru.getRef().isSymbolic() || !ru.getRef().getTarget()
						.getName().equals(expTarget)) {
					setResult(Result.LOCK_FAILURE);
					return;
				}
			}

			ru.setRefLogIdent(rp.getRefLogIdent());
			ru.setRefLogMessage(refLogMessage, refLogIncludeResult);
			switch (getType()) {
			case DELETE:
				if (!ObjectId.zeroId().equals(getOldId())) {
					// We can only do a CAS style delete if the client
					// didn't bork its delete request by sending the
					// wrong zero id rather than the advertised one.
					//
					ru.setExpectedOldObjectId(getOldId());
				}
				ru.setForceUpdate(true);
				setResult(ru.delete(rp.getRevWalk()));
				break;

			case CREATE:
			case UPDATE:
			case UPDATE_NONFASTFORWARD:
				ru.setForceUpdate(rp.isAllowNonFastForwards());
				ru.setExpectedOldObjectId(getOldId());
				ru.setRefLogMessage("push", true); //$NON-NLS-1$
				if (getNewSymref() != null) {
					setResult(ru.link(getNewSymref()));
				} else {
					ru.setNewObjectId(getNewId());
					setResult(ru.update(rp.getRevWalk()));
				}
				break;
			}
		} catch (IOException err) {
			reject(err);
		}
	}

	void setRef(Ref r) {
		ref = r;
	}

	void setType(Type t) {
		type = t;
	}

	void setTypeFastForwardUpdate() {
		type = Type.UPDATE;
		typeIsCorrect = true;
	}

	
Set the result of this command.
Params:
r – 
           the new result code for this command./**
	 * Set the result of this command.
	 *
	 * @param r
	 *            the new result code for this command.
	 */
	public void setResult(RefUpdate.Result r) {
		switch (r) {
		case NOT_ATTEMPTED:
			setResult(Result.NOT_ATTEMPTED);
			break;

		case LOCK_FAILURE:
		case IO_FAILURE:
			setResult(Result.LOCK_FAILURE);
			break;

		case NO_CHANGE:
		case NEW:
		case FORCED:
		case FAST_FORWARD:
			setResult(Result.OK);
			break;

		case REJECTED:
			setResult(Result.REJECTED_NONFASTFORWARD);
			break;

		case REJECTED_CURRENT_BRANCH:
			setResult(Result.REJECTED_CURRENT_BRANCH);
			break;

		case REJECTED_MISSING_OBJECT:
			setResult(Result.REJECTED_MISSING_OBJECT);
			break;

		case REJECTED_OTHER_REASON:
			setResult(Result.REJECTED_OTHER_REASON);
			break;

		default:
			setResult(Result.REJECTED_OTHER_REASON, r.name());
			break;
		}
	}

	void reject(IOException err) {
		setResult(Result.REJECTED_OTHER_REASON, MessageFormat.format(
				JGitText.get().lockError, err.getMessage()));
	}

	
{@inheritDoc} /** {@inheritDoc} */
	@SuppressWarnings("nls")
	@Override
	public String toString() {
		return getType().name() + ": " + getOldId().name() + " "
				+ getNewId().name() + " " + getRefName();
	}
}