/*
    * Copyright (C) 2008, 2013 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
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   * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
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   * 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,
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  package org.eclipse.jgit.transport;
  
  import java.io.Serializable;
  import java.text.MessageFormat;
  
  import org.eclipse.jgit.internal.JGitText;
  import org.eclipse.jgit.lib.Constants;
  import org.eclipse.jgit.lib.Ref;
  
  /**
   * Describes how refs in one repository copy into another repository.
   * <p>
   * A ref specification provides matching support and limited rules to rewrite a
   * reference in one repository to another reference in another repository.
   */
  public class RefSpec implements Serializable {
  	private static final long serialVersionUID = 1L;
  
  	/**
  	 * Suffix for wildcard ref spec component, that indicate matching all refs
  	 * with specified prefix.
  	 */
  	public static final String WILDCARD_SUFFIX = "/*"; //$NON-NLS-1$
  
  	/**
  	 * Check whether provided string is a wildcard ref spec component.
  	 *
  	 * @param s
  	 *            ref spec component - string to test. Can be null.
  	 * @return true if provided string is a wildcard ref spec component.
  	 */
  	public static boolean isWildcard(final String s) {
  		return s != null && s.contains("*"); //$NON-NLS-1$
  	}
  
  	/** Does this specification ask for forced updated (rewind/reset)? */
  	private boolean force;
  
  	/** Is this specification actually a wildcard match? */
  	private boolean wildcard;
  
  	/** Name of the ref(s) we would copy from. */
  	private String srcName;
  
  	/** Name of the ref(s) we would copy into. */
  	private String dstName;
  
  	/**
  	 * Construct an empty RefSpec.
  	 * <p>
  	 * A newly created empty RefSpec is not suitable for use in most
  	 * applications, as at least one field must be set to match a source name.
  	 */
  	public RefSpec() {
  		force = false;
  		wildcard = false;
 		srcName = Constants.HEAD;
 		dstName = null;
 	}
 
 	/**
 	 * Parse a ref specification for use during transport operations.
 	 * <p>
 	 * Specifications are typically one of the following forms:
 	 * <ul>
 	 * <li><code>refs/heads/master</code></li>
 	 * <li><code>refs/heads/master:refs/remotes/origin/master</code></li>
 	 * <li><code>refs/heads/*:refs/remotes/origin/*</code></li>
 	 * <li><code>+refs/heads/master</code></li>
 	 * <li><code>+refs/heads/master:refs/remotes/origin/master</code></li>
 	 * <li><code>+refs/heads/*:refs/remotes/origin/*</code></li>
 	 * <li><code>+refs/pull/&#42;/head:refs/remotes/origin/pr/*</code></li>
 	 * <li><code>:refs/heads/master</code></li>
 	 * </ul>
 	 *
 	 * @param spec
 	 *            string describing the specification.
 	 * @throws IllegalArgumentException
 	 *             the specification is invalid.
 	 */
 	public RefSpec(final String spec) {
 		String s = spec;
 		if (s.startsWith("+")) { //$NON-NLS-1$
 			force = true;
 			s = s.substring(1);
 		}
 
 		final int c = s.lastIndexOf(':');
 		if (c == 0) {
 			s = s.substring(1);
 			if (isWildcard(s))
 				throw new IllegalArgumentException(MessageFormat.format(JGitText.get().invalidWildcards, spec));
 			dstName = checkValid(s);
 		} else if (c > 0) {
 			String src = s.substring(0, c);
 			String dst = s.substring(c + 1);
 			if (isWildcard(src) && isWildcard(dst)) {
 				// Both contain wildcard
 				wildcard = true;
 			} else if (isWildcard(src) || isWildcard(dst)) {
 				// If either source or destination has wildcard, the other one
 				// must have as well.
 				throw new IllegalArgumentException(MessageFormat.format(JGitText.get().invalidWildcards, spec));
 			}
 			srcName = checkValid(src);
 			dstName = checkValid(dst);
 		} else {
 			if (isWildcard(s))
 				throw new IllegalArgumentException(MessageFormat.format(JGitText.get().invalidWildcards, spec));
 			srcName = checkValid(s);
 		}
 	}
 
 	private RefSpec(final RefSpec p) {
 		force = p.isForceUpdate();
 		wildcard = p.isWildcard();
 		srcName = p.getSource();
 		dstName = p.getDestination();
 	}
 
 	/**
 	 * Check if this specification wants to forcefully update the destination.
 	 *
 	 * @return true if this specification asks for updates without merge tests.
 	 */
 	public boolean isForceUpdate() {
 		return force;
 	}
 
 	/**
 	 * Create a new RefSpec with a different force update setting.
 	 *
 	 * @param forceUpdate
 	 *            new value for force update in the returned instance.
 	 * @return a new RefSpec with force update as specified.
 	 */
 	public RefSpec setForceUpdate(final boolean forceUpdate) {
 		final RefSpec r = new RefSpec(this);
 		r.force = forceUpdate;
 		return r;
 	}
 
 	/**
 	 * Check if this specification is actually a wildcard pattern.
 	 * <p>
 	 * If this is a wildcard pattern then the source and destination names
 	 * returned by {@link #getSource()} and {@link #getDestination()} will not
 	 * be actual ref names, but instead will be patterns.
 	 *
 	 * @return true if this specification could match more than one ref.
 	 */
 	public boolean isWildcard() {
 		return wildcard;
 	}
 
 	/**
 	 * Get the source ref description.
 	 * <p>
 	 * During a fetch this is the name of the ref on the remote repository we
 	 * are fetching from. During a push this is the name of the ref on the local
 	 * repository we are pushing out from.
 	 *
 	 * @return name (or wildcard pattern) to match the source ref.
 	 */
 	public String getSource() {
 		return srcName;
 	}
 
 	/**
 	 * Create a new RefSpec with a different source name setting.
 	 *
 	 * @param source
 	 *            new value for source in the returned instance.
 	 * @return a new RefSpec with source as specified.
 	 * @throws IllegalStateException
 	 *             There is already a destination configured, and the wildcard
 	 *             status of the existing destination disagrees with the
 	 *             wildcard status of the new source.
 	 */
 	public RefSpec setSource(final String source) {
 		final RefSpec r = new RefSpec(this);
 		r.srcName = checkValid(source);
 		if (isWildcard(r.srcName) && r.dstName == null)
 			throw new IllegalStateException(JGitText.get().destinationIsNotAWildcard);
 		if (isWildcard(r.srcName) != isWildcard(r.dstName))
 			throw new IllegalStateException(JGitText.get().sourceDestinationMustMatch);
 		return r;
 	}
 
 	/**
 	 * Get the destination ref description.
 	 * <p>
 	 * During a fetch this is the local tracking branch that will be updated
 	 * with the new ObjectId after fetching is complete. During a push this is
 	 * the remote ref that will be updated by the remote's receive-pack process.
 	 * <p>
 	 * If null during a fetch no tracking branch should be updated and the
 	 * ObjectId should be stored transiently in order to prepare a merge.
 	 * <p>
 	 * If null during a push, use {@link #getSource()} instead.
 	 *
 	 * @return name (or wildcard) pattern to match the destination ref.
 	 */
 	public String getDestination() {
 		return dstName;
 	}
 
 	/**
 	 * Create a new RefSpec with a different destination name setting.
 	 *
 	 * @param destination
 	 *            new value for destination in the returned instance.
 	 * @return a new RefSpec with destination as specified.
 	 * @throws IllegalStateException
 	 *             There is already a source configured, and the wildcard status
 	 *             of the existing source disagrees with the wildcard status of
 	 *             the new destination.
 	 */
 	public RefSpec setDestination(final String destination) {
 		final RefSpec r = new RefSpec(this);
 		r.dstName = checkValid(destination);
 		if (isWildcard(r.dstName) && r.srcName == null)
 			throw new IllegalStateException(JGitText.get().sourceIsNotAWildcard);
 		if (isWildcard(r.srcName) != isWildcard(r.dstName))
 			throw new IllegalStateException(JGitText.get().sourceDestinationMustMatch);
 		return r;
 	}
 
 	/**
 	 * Create a new RefSpec with a different source/destination name setting.
 	 *
 	 * @param source
 	 *            new value for source in the returned instance.
 	 * @param destination
 	 *            new value for destination in the returned instance.
 	 * @return a new RefSpec with destination as specified.
 	 * @throws IllegalArgumentException
 	 *             The wildcard status of the new source disagrees with the
 	 *             wildcard status of the new destination.
 	 */
 	public RefSpec setSourceDestination(final String source,
 			final String destination) {
 		if (isWildcard(source) != isWildcard(destination))
 			throw new IllegalStateException(JGitText.get().sourceDestinationMustMatch);
 		final RefSpec r = new RefSpec(this);
 		r.wildcard = isWildcard(source);
 		r.srcName = source;
 		r.dstName = destination;
 		return r;
 	}
 
 	/**
 	 * Does this specification's source description match the ref name?
 	 *
 	 * @param r
 	 *            ref name that should be tested.
 	 * @return true if the names match; false otherwise.
 	 */
 	public boolean matchSource(final String r) {
 		return match(r, getSource());
 	}
 
 	/**
 	 * Does this specification's source description match the ref?
 	 *
 	 * @param r
 	 *            ref whose name should be tested.
 	 * @return true if the names match; false otherwise.
 	 */
 	public boolean matchSource(final Ref r) {
 		return match(r.getName(), getSource());
 	}
 
 	/**
 	 * Does this specification's destination description match the ref name?
 	 *
 	 * @param r
 	 *            ref name that should be tested.
 	 * @return true if the names match; false otherwise.
 	 */
 	public boolean matchDestination(final String r) {
 		return match(r, getDestination());
 	}
 
 	/**
 	 * Does this specification's destination description match the ref?
 	 *
 	 * @param r
 	 *            ref whose name should be tested.
 	 * @return true if the names match; false otherwise.
 	 */
 	public boolean matchDestination(final Ref r) {
 		return match(r.getName(), getDestination());
 	}
 
 	/**
 	 * Expand this specification to exactly match a ref name.
 	 * <p>
 	 * Callers must first verify the passed ref name matches this specification,
 	 * otherwise expansion results may be unpredictable.
 	 *
 	 * @param r
 	 *            a ref name that matched our source specification. Could be a
 	 *            wildcard also.
 	 * @return a new specification expanded from provided ref name. Result
 	 *         specification is wildcard if and only if provided ref name is
 	 *         wildcard.
 	 */
 	public RefSpec expandFromSource(final String r) {
 		return isWildcard() ? new RefSpec(this).expandFromSourceImp(r) : this;
 	}
 
 	private RefSpec expandFromSourceImp(final String name) {
 		final String psrc = srcName, pdst = dstName;
 		wildcard = false;
 		srcName = name;
 		dstName = expandWildcard(name, psrc, pdst);
 		return this;
 	}
 
 	/**
 	 * Expand this specification to exactly match a ref.
 	 * <p>
 	 * Callers must first verify the passed ref matches this specification,
 	 * otherwise expansion results may be unpredictable.
 	 *
 	 * @param r
 	 *            a ref that matched our source specification. Could be a
 	 *            wildcard also.
 	 * @return a new specification expanded from provided ref name. Result
 	 *         specification is wildcard if and only if provided ref name is
 	 *         wildcard.
 	 */
 	public RefSpec expandFromSource(final Ref r) {
 		return expandFromSource(r.getName());
 	}
 
 	/**
 	 * Expand this specification to exactly match a ref name.
 	 * <p>
 	 * Callers must first verify the passed ref name matches this specification,
 	 * otherwise expansion results may be unpredictable.
 	 *
 	 * @param r
 	 *            a ref name that matched our destination specification. Could
 	 *            be a wildcard also.
 	 * @return a new specification expanded from provided ref name. Result
 	 *         specification is wildcard if and only if provided ref name is
 	 *         wildcard.
 	 */
 	public RefSpec expandFromDestination(final String r) {
 		return isWildcard() ? new RefSpec(this).expandFromDstImp(r) : this;
 	}
 
 	private RefSpec expandFromDstImp(final String name) {
 		final String psrc = srcName, pdst = dstName;
 		wildcard = false;
 		srcName = expandWildcard(name, pdst, psrc);
 		dstName = name;
 		return this;
 	}
 
 	/**
 	 * Expand this specification to exactly match a ref.
 	 * <p>
 	 * Callers must first verify the passed ref matches this specification,
 	 * otherwise expansion results may be unpredictable.
 	 *
 	 * @param r
 	 *            a ref that matched our destination specification.
 	 * @return a new specification expanded from provided ref name. Result
 	 *         specification is wildcard if and only if provided ref name is
 	 *         wildcard.
 	 */
 	public RefSpec expandFromDestination(final Ref r) {
 		return expandFromDestination(r.getName());
 	}
 
 	private boolean match(final String name, final String s) {
 		if (s == null)
 			return false;
 		if (isWildcard()) {
 			int wildcardIndex = s.indexOf('*');
 			String prefix = s.substring(0, wildcardIndex);
 			String suffix = s.substring(wildcardIndex + 1);
 			return name.length() > prefix.length() + suffix.length()
 					&& name.startsWith(prefix) && name.endsWith(suffix);
 		}
 		return name.equals(s);
 	}
 
 	private static String expandWildcard(String name, String patternA,
 			String patternB) {
 		int a = patternA.indexOf('*');
 		int trailingA = patternA.length() - (a + 1);
 		int b = patternB.indexOf('*');
 		String match = name.substring(a, name.length() - trailingA);
 		return patternB.substring(0, b) + match + patternB.substring(b + 1);
 	}
 
 	private static String checkValid(String spec) {
 		if (spec != null && !isValid(spec))
 			throw new IllegalArgumentException(MessageFormat.format(
 					JGitText.get().invalidRefSpec, spec));
 		return spec;
 	}
 
 	private static boolean isValid(final String s) {
 		if (s.startsWith("/")) //$NON-NLS-1$
 			return false;
 		if (s.contains("//")) //$NON-NLS-1$
 			return false;
 		int i = s.indexOf('*');
 		if (i != -1) {
 			if (s.indexOf('*', i + 1) > i)
 				return false;
 			if (i > 0 && s.charAt(i - 1) != '/')
 				return false;
 			if (i < s.length() - 1 && s.charAt(i + 1) != '/')
 				return false;
 		}
 		return true;
 	}
 
 	public int hashCode() {
 		int hc = 0;
 		if (getSource() != null)
 			hc = hc * 31 + getSource().hashCode();
 		if (getDestination() != null)
 			hc = hc * 31 + getDestination().hashCode();
 		return hc;
 	}
 
 	public boolean equals(final Object obj) {
 		if (!(obj instanceof RefSpec))
 			return false;
 		final RefSpec b = (RefSpec) obj;
 		if (isForceUpdate() != b.isForceUpdate())
 			return false;
 		if (isWildcard() != b.isWildcard())
 			return false;
 		if (!eq(getSource(), b.getSource()))
 			return false;
 		if (!eq(getDestination(), b.getDestination()))
 			return false;
 		return true;
 	}
 
 	private static boolean eq(final String a, final String b) {
 		if (a == b)
 			return true;
 		if (a == null || b == null)
 			return false;
 		return a.equals(b);
 	}
 
 	public String toString() {
 		final StringBuilder r = new StringBuilder();
 		if (isForceUpdate())
 			r.append('+');
 		if (getSource() != null)
 			r.append(getSource());
 		if (getDestination() != null) {
 			r.append(':');
 			r.append(getDestination());
 		}
 		return r.toString();
 	}
 }