Java tutorial
/******************************************************************************* * Copyright (c) 2010 SAP AG. * All rights reserved. This program and the accompanying materials * are made available under the terms of the Eclipse Public License v1.0 * which accompanies this distribution, and is available at * http://www.eclipse.org/legal/epl-v10.html * * Contributors: * Mathias Kinzler (SAP AG) - initial implementation *******************************************************************************/ package org.eclipse.egit.ui; import java.io.File; import java.io.IOException; import java.util.Date; import java.util.HashMap; import java.util.Map; import java.util.Set; import java.util.TreeSet; import org.eclipse.jgit.lib.Constants; import org.eclipse.jgit.lib.ObjectId; import org.eclipse.jgit.lib.Ref; import org.eclipse.jgit.lib.Repository; import org.eclipse.jgit.lib.Tag; /** * Utility class for handling Repositories in the UI. */ public class RepositoryUtil { private final Map<String, Map<String, String>> commitMappingCache = new HashMap<String, Map<String, String>>(); private final Map<String, String> repositoryNameCache = new HashMap<String, String>(); /** * Clients should obtain an instance from {@link Activator} */ RepositoryUtil() { // nothing } /** * Used by {@link Activator} */ void dispose() { commitMappingCache.clear(); repositoryNameCache.clear(); } /** * Tries to map a commit to a symbolic reference. * <p> * This value will be cached for the given commit ID unless refresh is * specified. The return value will be the full name, e.g. * "refs/remotes/someBranch", "refs/tags/v.1.0" * <p> * Since this mapping is not unique, the following precedence rules are * used: * <ul> * <li>Tags take precedence over branches</li> * <li>Local branches take preference over remote branches</li> * <li>Newer references take precedence over older ones where time stamps * are available</li> * <li>If there are still ambiguities, the reference name with the highest * lexicographic value will be returned</li> * </ul> * * @param repository * the {@link Repository} * @param commitId * a commit * @param refresh * if true, the cache will be invalidated * @return the symbolic reference, or <code>null</code> if no such reference * can be found */ public String mapCommitToRef(Repository repository, String commitId, boolean refresh) { synchronized (commitMappingCache) { if (!ObjectId.isId(commitId)) { return null; } Map<String, String> cacheEntry = commitMappingCache.get(repository.getDirectory().toString()); if (!refresh && cacheEntry != null && cacheEntry.containsKey(commitId)) { // this may be null in fact return cacheEntry.get(commitId); } if (cacheEntry == null) { cacheEntry = new HashMap<String, String>(); commitMappingCache.put(repository.getDirectory().getPath(), cacheEntry); } else { cacheEntry.clear(); } Map<String, Date> tagMap = new HashMap<String, Date>(); try { Map<String, Ref> tags = repository.getRefDatabase().getRefs(Constants.R_TAGS); for (Ref tagRef : tags.values()) { Tag tag = repository.mapTag(tagRef.getName()); if (tag.getObjId().name().equals(commitId)) { Date timestamp; if (tag.getTagger() != null) { timestamp = tag.getTagger().getWhen(); } else { timestamp = null; } tagMap.put(tagRef.getName(), timestamp); } } } catch (IOException e) { // ignore here } String cacheValue = null; if (!tagMap.isEmpty()) { // we try to obtain the "latest" tag Date compareDate = new Date(0); for (Map.Entry<String, Date> tagEntry : tagMap.entrySet()) { if (tagEntry.getValue() != null && tagEntry.getValue().after(compareDate)) { compareDate = tagEntry.getValue(); cacheValue = tagEntry.getKey(); } } // if we don't have time stamps, we sort if (cacheValue == null) { String compareString = ""; //$NON-NLS-1$ for (String tagName : tagMap.keySet()) { if (tagName.compareTo(compareString) >= 0) { cacheValue = tagName; compareString = tagName; } } } } if (cacheValue == null) { // we didnt't find a tag, so let's look for local branches Set<String> branchNames = new TreeSet<String>(); // put this into a sorted set try { Map<String, Ref> remoteBranches = repository.getRefDatabase().getRefs(Constants.R_HEADS); for (Ref branch : remoteBranches.values()) { if (branch.getObjectId().name().equals(commitId)) { branchNames.add(branch.getName()); } } } catch (IOException e) { // ignore here } if (!branchNames.isEmpty()) { // get the last (sorted) entry cacheValue = branchNames.toArray(new String[branchNames.size()])[branchNames.size() - 1]; } } if (cacheValue == null) { // last try: remote branches Set<String> branchNames = new TreeSet<String>(); // put this into a sorted set try { Map<String, Ref> remoteBranches = repository.getRefDatabase().getRefs(Constants.R_REMOTES); for (Ref branch : remoteBranches.values()) { if (branch.getObjectId().name().equals(commitId)) { branchNames.add(branch.getName()); } } if (!branchNames.isEmpty()) { // get the last (sorted) entry cacheValue = branchNames.toArray(new String[branchNames.size()])[branchNames.size() - 1]; } } catch (IOException e) { // ignore here } } cacheEntry.put(commitId, cacheValue); return cacheValue; } } /** * Return a cached UI "name" for a Repository * <p> * This uses the name of the parent of the repository's directory. * * @param repository * @return the name */ public String getRepositoryName(Repository repository) { synchronized (repositoryNameCache) { File gitDir = repository.getDirectory(); if (gitDir != null) { String name = repositoryNameCache.get(gitDir.getPath().toString()); if (name != null) { return name; } name = gitDir.getParentFile().getName(); repositoryNameCache.put(gitDir.getPath().toString(), name); return name; } } return ""; //$NON-NLS-1$ } }