org.eclipse.jgit/src/org/eclipse/jgit/transport/PreReceiveHook.java

/*
 * 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
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package org.eclipse.jgit.transport;

import java.util.Collection;

/**
 * Hook invoked by {@link ReceivePack} before any updates are executed.
 * <p>
 * The hook is called with any commands that are deemed valid after parsing them
 * from the client and applying the standard receive configuration options to
 * them:
 * <ul>
 * <li><code>receive.denyDenyDeletes</code></li>
 * <li><code>receive.denyNonFastForwards</code></li>
 * </ul>
 * This means the hook will not receive a non-fast-forward update command if
 * denyNonFastForwards is set to true in the configuration file. To get all
 * commands within the hook, see {@link ReceivePack#getAllCommands()}.
 * <p>
 * As the hook is invoked prior to the commands being executed, the hook may
 * choose to block any command by setting its result status with
 * {@link ReceiveCommand#setResult(ReceiveCommand.Result)}.
 * <p>
 * The hook may also choose to perform the command itself (or merely pretend
 * that it has performed the command), by setting the result status to
 * {@link ReceiveCommand.Result#OK}.
 * <p>
 * Hooks should run quickly, as they block the caller thread and the client
 * process from completing.
 * <p>
 * Hooks may send optional messages back to the client via methods on
 * {@link ReceivePack}. Implementors should be aware that not all network
 * transports support this output, so some (or all) messages may simply be
 * discarded. These messages should be advisory only.
 */
public interface PreReceiveHook {
	/** A simple no-op hook. */
	public static final PreReceiveHook NULL = new PreReceiveHook() {
		@Override
		public void onPreReceive(final ReceivePack rp,
				final Collection<ReceiveCommand> commands) {
			// Do nothing.
		}
	};

	/**
	 * Invoked just before commands are executed.
	 * <p>
	 * See the class description for how this method can impact execution.
	 *
	 * @param rp
	 *            the process handling the current receive. Hooks may obtain
	 *            details about the destination repository through this handle.
	 * @param commands
	 *            unmodifiable set of valid commands still pending execution.
	 *            May be the empty set.
	 */
	public void onPreReceive(ReceivePack rp, Collection<ReceiveCommand> commands);
}