org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/FileRepository.java - jgit/jgit - Git at Google

 /*
  * Copyright (C) 2007, Dave Watson <dwatson@mimvista.com>
  * Copyright (C) 2008-2010, Google Inc.
  * Copyright (C) 2006-2010, Robin Rosenberg <robin.rosenberg@dewire.com>
  * Copyright (C) 2006-2008, 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
  * 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.internal.storage.file;

 import static org.eclipse.jgit.lib.RefDatabase.ALL;

 import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.text.MessageFormat;
 import java.text.ParseException;
 import java.util.HashSet;
 import java.util.Locale;
 import java.util.Objects;
 import java.util.Set;

 import org.eclipse.jgit.annotations.Nullable;
 import org.eclipse.jgit.api.errors.JGitInternalException;
 import org.eclipse.jgit.attributes.AttributesNode;
 import org.eclipse.jgit.attributes.AttributesNodeProvider;
 import org.eclipse.jgit.errors.ConfigInvalidException;
 import org.eclipse.jgit.events.ConfigChangedEvent;
 import org.eclipse.jgit.events.ConfigChangedListener;
 import org.eclipse.jgit.events.IndexChangedEvent;
 import org.eclipse.jgit.internal.JGitText;
 import org.eclipse.jgit.internal.storage.file.ObjectDirectory.AlternateHandle;
 import org.eclipse.jgit.internal.storage.file.ObjectDirectory.AlternateRepository;
 import org.eclipse.jgit.internal.storage.reftree.RefTreeDatabase;
 import org.eclipse.jgit.lib.BaseRepositoryBuilder;
 import org.eclipse.jgit.lib.ConfigConstants;
 import org.eclipse.jgit.lib.Constants;
 import org.eclipse.jgit.lib.CoreConfig.HideDotFiles;
 import org.eclipse.jgit.lib.CoreConfig.SymLinks;
 import org.eclipse.jgit.lib.ObjectId;
 import org.eclipse.jgit.lib.ProgressMonitor;
 import org.eclipse.jgit.lib.Ref;
 import org.eclipse.jgit.lib.RefDatabase;
 import org.eclipse.jgit.lib.RefUpdate;
 import org.eclipse.jgit.lib.ReflogReader;
 import org.eclipse.jgit.lib.Repository;
 import org.eclipse.jgit.storage.file.FileBasedConfig;
 import org.eclipse.jgit.storage.file.FileRepositoryBuilder;
 import org.eclipse.jgit.storage.pack.PackConfig;
 import org.eclipse.jgit.util.FS;
 import org.eclipse.jgit.util.FileUtils;
 import org.eclipse.jgit.util.IO;
 import org.eclipse.jgit.util.RawParseUtils;
 import org.eclipse.jgit.util.StringUtils;
 import org.eclipse.jgit.util.SystemReader;

 /**
  * Represents a Git repository. A repository holds all objects and refs used for
  * managing source code (could by any type of file, but source code is what
  * SCM's are typically used for).
  *
  * In Git terms all data is stored in GIT_DIR, typically a directory called
  * .git. A work tree is maintained unless the repository is a bare repository.
  * Typically the .git directory is located at the root of the work dir.
  *
  * <ul>
  * <li>GIT_DIR
  * 	<ul>
  * 		<li>objects/ - objects</li>
  * 		<li>refs/ - tags and heads</li>
  * 		<li>config - configuration</li>
  * 		<li>info/ - more configurations</li>
  * 	</ul>
  * </li>
  * </ul>
  * <p>
  * This class is thread-safe.
  * <p>
  * This implementation only handles a subtly undocumented subset of git features.
  *
  */
 public class FileRepository extends Repository {
 	private static final String UNNAMED = "Unnamed repository; edit this file to name it for gitweb."; //$NON-NLS-1$

 	private final FileBasedConfig systemConfig;
 	private final FileBasedConfig userConfig;
 	private final FileBasedConfig repoConfig;
 	private final RefDatabase refs;
 	private final ObjectDirectory objectDatabase;
 	private FileSnapshot snapshot;

 	/**
 	 * Construct a representation of a Git repository.
 	 * <p>
 	 * The work tree, object directory, alternate object directories and index
 	 * file locations are deduced from the given git directory and the default
 	 * rules by running {@link FileRepositoryBuilder}. This constructor is the
 	 * same as saying:
 	 *
 	 * <pre>
 	 * new FileRepositoryBuilder().setGitDir(gitDir).build()
 	 * </pre>
 	 *
 	 * @param gitDir
 	 *            GIT_DIR (the location of the repository metadata).
 	 * @throws IOException
 	 *             the repository appears to already exist but cannot be
 	 *             accessed.
 	 * @see FileRepositoryBuilder
 	 */
 	public FileRepository(final File gitDir) throws IOException {
 		this(new FileRepositoryBuilder().setGitDir(gitDir).setup());
 	}

 	/**
 	 * A convenience API for {@link #FileRepository(File)}.
 	 *
 	 * @param gitDir
 	 *            GIT_DIR (the location of the repository metadata).
 	 * @throws IOException
 	 *             the repository appears to already exist but cannot be
 	 *             accessed.
 	 * @see FileRepositoryBuilder
 	 */
 	public FileRepository(final String gitDir) throws IOException {
 		this(new File(gitDir));
 	}

 	/**
 	 * Create a repository using the local file system.
 	 *
 	 * @param options
 	 *            description of the repository's important paths.
 	 * @throws IOException
 	 *             the user configuration file or repository configuration file
 	 *             cannot be accessed.
 	 */
 	public FileRepository(final BaseRepositoryBuilder options) throws IOException {
 		super(options);

 		if (StringUtils.isEmptyOrNull(SystemReader.getInstance().getenv(
 				Constants.GIT_CONFIG_NOSYSTEM_KEY)))
 			systemConfig = SystemReader.getInstance().openSystemConfig(null,
 					getFS());
 		else
 			systemConfig = new FileBasedConfig(null, FS.DETECTED) {
 				@Override
 				public void load() {
 					// empty, do not load
 				}

 				@Override
 				public boolean isOutdated() {
 					// regular class would bomb here
 					return false;
 				}
 			};
 		userConfig = SystemReader.getInstance().openUserConfig(systemConfig,
 				getFS());
 		repoConfig = new FileBasedConfig(userConfig, getFS().resolve(
 				getDirectory(), Constants.CONFIG),
 				getFS());

 		loadSystemConfig();
 		loadUserConfig();
 		loadRepoConfig();

 		repoConfig.addChangeListener(new ConfigChangedListener() {
 			@Override
 			public void onConfigChanged(ConfigChangedEvent event) {
 				fireEvent(event);
 			}
 		});

 		final long repositoryFormatVersion = getConfig().getLong(
 				ConfigConstants.CONFIG_CORE_SECTION, null,
 				ConfigConstants.CONFIG_KEY_REPO_FORMAT_VERSION, 0);

 		String reftype = repoConfig.getString(
 				"extensions", null, "refsStorage"); //$NON-NLS-1$ //$NON-NLS-2$
 		if (repositoryFormatVersion >= 1 && reftype != null) {
 			if (StringUtils.equalsIgnoreCase(reftype, "reftree")) { //$NON-NLS-1$
 				refs = new RefTreeDatabase(this, new RefDirectory(this));
 			} else {
 				throw new IOException(JGitText.get().unknownRepositoryFormat);
 			}
 		} else {
 			refs = new RefDirectory(this);
 		}

 		objectDatabase = new ObjectDirectory(repoConfig, //
 				options.getObjectDirectory(), //
 				options.getAlternateObjectDirectories(), //
 				getFS(), //
 				new File(getDirectory(), Constants.SHALLOW));

 		if (objectDatabase.exists()) {
 			if (repositoryFormatVersion > 1)
 				throw new IOException(MessageFormat.format(
 						JGitText.get().unknownRepositoryFormat2,
 						Long.valueOf(repositoryFormatVersion)));
 		}

 		if (!isBare())
 			snapshot = FileSnapshot.save(getIndexFile());
 	}

 	private void loadSystemConfig() throws IOException {
 		try {
 			systemConfig.load();
 		} catch (ConfigInvalidException e1) {
 			IOException e2 = new IOException(MessageFormat.format(JGitText
 					.get().systemConfigFileInvalid, systemConfig.getFile()
 					.getAbsolutePath(), e1));
 			e2.initCause(e1);
 			throw e2;
 		}
 	}

 	private void loadUserConfig() throws IOException {
 		try {
 			userConfig.load();
 		} catch (ConfigInvalidException e1) {
 			IOException e2 = new IOException(MessageFormat.format(JGitText
 					.get().userConfigFileInvalid, userConfig.getFile()
 					.getAbsolutePath(), e1));
 			e2.initCause(e1);
 			throw e2;
 		}
 	}

 	private void loadRepoConfig() throws IOException {
 		try {
 			repoConfig.load();
 		} catch (ConfigInvalidException e1) {
 			IOException e2 = new IOException(JGitText.get().unknownRepositoryFormat);
 			e2.initCause(e1);
 			throw e2;
 		}
 	}

 	/**
 	 * Create a new Git repository initializing the necessary files and
 	 * directories.
 	 *
 	 * @param bare
 	 *            if true, a bare repository is created.
 	 *
 	 * @throws IOException
 	 *             in case of IO problem
 	 */
 	@Override
 	public void create(boolean bare) throws IOException {
 		final FileBasedConfig cfg = getConfig();
 		if (cfg.getFile().exists()) {
 			throw new IllegalStateException(MessageFormat.format(
 					JGitText.get().repositoryAlreadyExists, getDirectory()));
 		}
 		FileUtils.mkdirs(getDirectory(), true);
 		HideDotFiles hideDotFiles = getConfig().getEnum(
 				ConfigConstants.CONFIG_CORE_SECTION, null,
 				ConfigConstants.CONFIG_KEY_HIDEDOTFILES,
 				HideDotFiles.DOTGITONLY);
 		if (hideDotFiles != HideDotFiles.FALSE && !isBare()
 				&& getDirectory().getName().startsWith(".")) //$NON-NLS-1$
 			getFS().setHidden(getDirectory(), true);
 		refs.create();
 		objectDatabase.create();

 		FileUtils.mkdir(new File(getDirectory(), "branches")); //$NON-NLS-1$
 		FileUtils.mkdir(new File(getDirectory(), "hooks")); //$NON-NLS-1$

 		RefUpdate head = updateRef(Constants.HEAD);
 		head.disableRefLog();
 		head.link(Constants.R_HEADS + Constants.MASTER);

 		final boolean fileMode;
 		if (getFS().supportsExecute()) {
 			File tmp = File.createTempFile("try", "execute", getDirectory()); //$NON-NLS-1$ //$NON-NLS-2$

 			getFS().setExecute(tmp, true);
 			final boolean on = getFS().canExecute(tmp);

 			getFS().setExecute(tmp, false);
 			final boolean off = getFS().canExecute(tmp);
 			FileUtils.delete(tmp);

 			fileMode = on && !off;
 		} else {
 			fileMode = false;
 		}

 		SymLinks symLinks = SymLinks.FALSE;
 		if (getFS().supportsSymlinks()) {
 			File tmp = new File(getDirectory(), "tmplink"); //$NON-NLS-1$
 			try {
 				getFS().createSymLink(tmp, "target"); //$NON-NLS-1$
 				symLinks = null;
 				FileUtils.delete(tmp);
 			} catch (IOException e) {
 				// Normally a java.nio.file.FileSystemException
 			}
 		}
 		if (symLinks != null)
 			cfg.setString(ConfigConstants.CONFIG_CORE_SECTION, null,
 					ConfigConstants.CONFIG_KEY_SYMLINKS, symLinks.name()
 							.toLowerCase(Locale.ROOT));
 		cfg.setInt(ConfigConstants.CONFIG_CORE_SECTION, null,
 				ConfigConstants.CONFIG_KEY_REPO_FORMAT_VERSION, 0);
 		cfg.setBoolean(ConfigConstants.CONFIG_CORE_SECTION, null,
 				ConfigConstants.CONFIG_KEY_FILEMODE, fileMode);
 		if (bare)
 			cfg.setBoolean(ConfigConstants.CONFIG_CORE_SECTION, null,
 					ConfigConstants.CONFIG_KEY_BARE, true);
 		cfg.setBoolean(ConfigConstants.CONFIG_CORE_SECTION, null,
 				ConfigConstants.CONFIG_KEY_LOGALLREFUPDATES, !bare);
 		if (SystemReader.getInstance().isMacOS())
 			// Java has no other way
 			cfg.setBoolean(ConfigConstants.CONFIG_CORE_SECTION, null,
 					ConfigConstants.CONFIG_KEY_PRECOMPOSEUNICODE, true);
 		if (!bare) {
 			File workTree = getWorkTree();
 			if (!getDirectory().getParentFile().equals(workTree)) {
 				cfg.setString(ConfigConstants.CONFIG_CORE_SECTION, null,
 						ConfigConstants.CONFIG_KEY_WORKTREE, getWorkTree()
 								.getAbsolutePath());
 				LockFile dotGitLockFile = new LockFile(new File(workTree,
 						Constants.DOT_GIT));
 				try {
 					if (dotGitLockFile.lock()) {
 						dotGitLockFile.write(Constants.encode(Constants.GITDIR
 								+ getDirectory().getAbsolutePath()));
 						dotGitLockFile.commit();
 					}
 				} finally {
 					dotGitLockFile.unlock();
 				}
 			}
 		}
 		cfg.save();
 	}

 	/**
 	 * @return the directory containing the objects owned by this repository.
 	 */
 	public File getObjectsDirectory() {
 		return objectDatabase.getDirectory();
 	}

 	/** @return the object database storing this repository's data. */
 	@Override
 	public ObjectDirectory getObjectDatabase() {
 		return objectDatabase;
 	}

 	/** @return the reference database which stores the reference namespace. */
 	@Override
 	public RefDatabase getRefDatabase() {
 		return refs;
 	}

 	/** @return the configuration of this repository. */
 	@Override
 	public FileBasedConfig getConfig() {
 		if (systemConfig.isOutdated()) {
 			try {
 				loadSystemConfig();
 			} catch (IOException e) {
 				throw new RuntimeException(e);
 			}
 		}
 		if (userConfig.isOutdated()) {
 			try {
 				loadUserConfig();
 			} catch (IOException e) {
 				throw new RuntimeException(e);
 			}
 		}
 		if (repoConfig.isOutdated()) {
 				try {
 					loadRepoConfig();
 				} catch (IOException e) {
 					throw new RuntimeException(e);
 				}
 		}
 		return repoConfig;
 	}

 	@Override
 	@Nullable
 	public String getGitwebDescription() throws IOException {
 		String d;
 		try {
 			d = RawParseUtils.decode(IO.readFully(descriptionFile()));
 		} catch (FileNotFoundException err) {
 			return null;
 		}
 		if (d != null) {
 			d = d.trim();
 			if (d.isEmpty() || UNNAMED.equals(d)) {
 				return null;
 			}
 		}
 		return d;
 	}

 	@Override
 	public void setGitwebDescription(@Nullable String description)
 			throws IOException {
 		String old = getGitwebDescription();
 		if (Objects.equals(old, description)) {
 			return;
 		}

 		File path = descriptionFile();
 		LockFile lock = new LockFile(path);
 		if (!lock.lock()) {
 			throw new IOException(MessageFormat.format(JGitText.get().lockError,
 					path.getAbsolutePath()));
 		}
 		try {
 			String d = description;
 			if (d != null) {
 				d = d.trim();
 				if (!d.isEmpty()) {
 					d += '\n';
 				}
 			} else {
 				d = ""; //$NON-NLS-1$
 			}
 			lock.write(Constants.encode(d));
 			lock.commit();
 		} finally {
 			lock.unlock();
 		}
 	}

 	private File descriptionFile() {
 		return new File(getDirectory(), "description"); //$NON-NLS-1$
 	}

 	/**
 	 * Objects known to exist but not expressed by {@link #getAllRefs()}.
 	 * <p>
 	 * When a repository borrows objects from another repository, it can
 	 * advertise that it safely has that other repository's references, without
 	 * exposing any other details about the other repository.  This may help
 	 * a client trying to push changes avoid pushing more than it needs to.
 	 *
 	 * @return unmodifiable collection of other known objects.
 	 */
 	@Override
 	public Set<ObjectId> getAdditionalHaves() {
 		HashSet<ObjectId> r = new HashSet<>();
 		for (AlternateHandle d : objectDatabase.myAlternates()) {
 			if (d instanceof AlternateRepository) {
 				Repository repo;

 				repo = ((AlternateRepository) d).repository;
 				for (Ref ref : repo.getAllRefs().values()) {
 					if (ref.getObjectId() != null)
 						r.add(ref.getObjectId());
 					if (ref.getPeeledObjectId() != null)
 						r.add(ref.getPeeledObjectId());
 				}
 				r.addAll(repo.getAdditionalHaves());
 			}
 		}
 		return r;
 	}

 	/**
 	 * Add a single existing pack to the list of available pack files.
 	 *
 	 * @param pack
 	 *            path of the pack file to open.
 	 * @throws IOException
 	 *             index file could not be opened, read, or is not recognized as
 	 *             a Git pack file index.
 	 */
 	public void openPack(final File pack) throws IOException {
 		objectDatabase.openPack(pack);
 	}

 	@Override
 	public void scanForRepoChanges() throws IOException {
 		getRefDatabase().getRefs(ALL); // This will look for changes to refs
 		detectIndexChanges();
 	}

 	/** Detect index changes. */
 	private void detectIndexChanges() {
 		if (isBare())
 			return;

 		File indexFile = getIndexFile();
 		if (snapshot == null)
 			snapshot = FileSnapshot.save(indexFile);
 		else if (snapshot.isModified(indexFile))
 			notifyIndexChanged();
 	}

 	@Override
 	public void notifyIndexChanged() {
 		snapshot = FileSnapshot.save(getIndexFile());
 		fireEvent(new IndexChangedEvent());
 	}

 	/**
 	 * @param refName
 	 * @return a {@link ReflogReader} for the supplied refname, or null if the
 	 *         named ref does not exist.
 	 * @throws IOException the ref could not be accessed.
 	 */
 	@Override
 	public ReflogReader getReflogReader(String refName) throws IOException {
 		Ref ref = findRef(refName);
 		if (ref != null)
 			return new ReflogReaderImpl(this, ref.getName());
 		return null;
 	}

 	@Override
 	public AttributesNodeProvider createAttributesNodeProvider() {
 		return new AttributesNodeProviderImpl(this);
 	}

 	/**
 	 * Implementation a {@link AttributesNodeProvider} for a
 	 * {@link FileRepository}.
 	 *
 	 * @author <a href="mailto:arthur.daussy@obeo.fr">Arthur Daussy</a>
 	 *
 	 */
 	static class AttributesNodeProviderImpl implements
 			AttributesNodeProvider {

 		private AttributesNode infoAttributesNode;

 		private AttributesNode globalAttributesNode;

 		/**
 		 * Constructor.
 		 *
 		 * @param repo
 		 *            {@link Repository} that will provide the attribute nodes.
 		 */
 		protected AttributesNodeProviderImpl(Repository repo) {
 			infoAttributesNode = new InfoAttributesNode(repo);
 			globalAttributesNode = new GlobalAttributesNode(repo);
 		}

 		@Override
 		public AttributesNode getInfoAttributesNode() throws IOException {
 			if (infoAttributesNode instanceof InfoAttributesNode)
 				infoAttributesNode = ((InfoAttributesNode) infoAttributesNode)
 						.load();
 			return infoAttributesNode;
 		}

 		@Override
 		public AttributesNode getGlobalAttributesNode() throws IOException {
 			if (globalAttributesNode instanceof GlobalAttributesNode)
 				globalAttributesNode = ((GlobalAttributesNode) globalAttributesNode)
 						.load();
 			return globalAttributesNode;
 		}

 		static void loadRulesFromFile(AttributesNode r, File attrs)
 				throws FileNotFoundException, IOException {
 			if (attrs.exists()) {
 				FileInputStream in = new FileInputStream(attrs);
 				try {
 					r.parse(in);
 				} finally {
 					in.close();
 				}
 			}
 		}

 	}

 	@Override
 	public void autoGC(ProgressMonitor monitor) {
 		GC gc = new GC(this);
 		gc.setPackConfig(new PackConfig(this));
 		gc.setProgressMonitor(monitor);
 		gc.setAuto(true);
 		try {
 			gc.gc();
 		} catch (ParseException | IOException e) {
 			throw new JGitInternalException(JGitText.get().gcFailed, e);
 		}
 	}
 }
	/*
	* Copyright (C) 2007, Dave Watson <dwatson@mimvista.com>
	* Copyright (C) 2008-2010, Google Inc.
	* Copyright (C) 2006-2010, Robin Rosenberg <robin.rosenberg@dewire.com>
	* Copyright (C) 2006-2008, 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
	* 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.internal.storage.file;

	import static org.eclipse.jgit.lib.RefDatabase.ALL;

	import java.io.File;
	import java.io.FileInputStream;
	import java.io.FileNotFoundException;
	import java.io.IOException;
	import java.text.MessageFormat;
	import java.text.ParseException;
	import java.util.HashSet;
	import java.util.Locale;
	import java.util.Objects;
	import java.util.Set;

	import org.eclipse.jgit.annotations.Nullable;
	import org.eclipse.jgit.api.errors.JGitInternalException;
	import org.eclipse.jgit.attributes.AttributesNode;
	import org.eclipse.jgit.attributes.AttributesNodeProvider;
	import org.eclipse.jgit.errors.ConfigInvalidException;
	import org.eclipse.jgit.events.ConfigChangedEvent;
	import org.eclipse.jgit.events.ConfigChangedListener;
	import org.eclipse.jgit.events.IndexChangedEvent;
	import org.eclipse.jgit.internal.JGitText;
	import org.eclipse.jgit.internal.storage.file.ObjectDirectory.AlternateHandle;
	import org.eclipse.jgit.internal.storage.file.ObjectDirectory.AlternateRepository;
	import org.eclipse.jgit.internal.storage.reftree.RefTreeDatabase;
	import org.eclipse.jgit.lib.BaseRepositoryBuilder;
	import org.eclipse.jgit.lib.ConfigConstants;
	import org.eclipse.jgit.lib.Constants;
	import org.eclipse.jgit.lib.CoreConfig.HideDotFiles;
	import org.eclipse.jgit.lib.CoreConfig.SymLinks;
	import org.eclipse.jgit.lib.ObjectId;
	import org.eclipse.jgit.lib.ProgressMonitor;
	import org.eclipse.jgit.lib.Ref;
	import org.eclipse.jgit.lib.RefDatabase;
	import org.eclipse.jgit.lib.RefUpdate;
	import org.eclipse.jgit.lib.ReflogReader;
	import org.eclipse.jgit.lib.Repository;
	import org.eclipse.jgit.storage.file.FileBasedConfig;
	import org.eclipse.jgit.storage.file.FileRepositoryBuilder;
	import org.eclipse.jgit.storage.pack.PackConfig;
	import org.eclipse.jgit.util.FS;
	import org.eclipse.jgit.util.FileUtils;
	import org.eclipse.jgit.util.IO;
	import org.eclipse.jgit.util.RawParseUtils;
	import org.eclipse.jgit.util.StringUtils;
	import org.eclipse.jgit.util.SystemReader;

	/**
	* Represents a Git repository. A repository holds all objects and refs used for
	* managing source code (could by any type of file, but source code is what
	* SCM's are typically used for).
	*
	* In Git terms all data is stored in GIT_DIR, typically a directory called
	* .git. A work tree is maintained unless the repository is a bare repository.
	* Typically the .git directory is located at the root of the work dir.
	*
	* <ul>
	* <li>GIT_DIR
	* <ul>
	* <li>objects/ - objects</li>
	* <li>refs/ - tags and heads</li>
	* <li>config - configuration</li>
	* <li>info/ - more configurations</li>
	* </ul>
	* </li>
	* </ul>
	* <p>
	* This class is thread-safe.
	* <p>
	* This implementation only handles a subtly undocumented subset of git features.
	*
	*/
	public class FileRepository extends Repository {
	private static final String UNNAMED = "Unnamed repository; edit this file to name it for gitweb."; //$NON-NLS-1$

	private final FileBasedConfig systemConfig;
	private final FileBasedConfig userConfig;
	private final FileBasedConfig repoConfig;
	private final RefDatabase refs;
	private final ObjectDirectory objectDatabase;
	private FileSnapshot snapshot;

	/**
	* Construct a representation of a Git repository.
	* <p>
	* The work tree, object directory, alternate object directories and index
	* file locations are deduced from the given git directory and the default
	* rules by running {@link FileRepositoryBuilder}. This constructor is the
	* same as saying:
	*
	* <pre>
	* new FileRepositoryBuilder().setGitDir(gitDir).build()
	* </pre>
	*
	* @param gitDir
	* GIT_DIR (the location of the repository metadata).
	* @throws IOException
	* the repository appears to already exist but cannot be
	* accessed.
	* @see FileRepositoryBuilder
	*/
	public FileRepository(final File gitDir) throws IOException {
	this(new FileRepositoryBuilder().setGitDir(gitDir).setup());
	}

	/**
	* A convenience API for {@link #FileRepository(File)}.
	*
	* @param gitDir
	* GIT_DIR (the location of the repository metadata).
	* @throws IOException
	* the repository appears to already exist but cannot be
	* accessed.
	* @see FileRepositoryBuilder
	*/
	public FileRepository(final String gitDir) throws IOException {
	this(new File(gitDir));
	}

	/**
	* Create a repository using the local file system.
	*
	* @param options
	* description of the repository's important paths.
	* @throws IOException
	* the user configuration file or repository configuration file
	* cannot be accessed.
	*/
	public FileRepository(final BaseRepositoryBuilder options) throws IOException {
	super(options);

	if (StringUtils.isEmptyOrNull(SystemReader.getInstance().getenv(
	Constants.GIT_CONFIG_NOSYSTEM_KEY)))
	systemConfig = SystemReader.getInstance().openSystemConfig(null,
	getFS());
	else
	systemConfig = new FileBasedConfig(null, FS.DETECTED) {
	@Override
	public void load() {
	// empty, do not load
	}

	@Override
	public boolean isOutdated() {
	// regular class would bomb here
	return false;
	}
	};
	userConfig = SystemReader.getInstance().openUserConfig(systemConfig,
	getFS());
	repoConfig = new FileBasedConfig(userConfig, getFS().resolve(
	getDirectory(), Constants.CONFIG),
	getFS());

	loadSystemConfig();
	loadUserConfig();
	loadRepoConfig();

	repoConfig.addChangeListener(new ConfigChangedListener() {
	@Override
	public void onConfigChanged(ConfigChangedEvent event) {
	fireEvent(event);
	}
	});

	final long repositoryFormatVersion = getConfig().getLong(
	ConfigConstants.CONFIG_CORE_SECTION, null,
	ConfigConstants.CONFIG_KEY_REPO_FORMAT_VERSION, 0);

	String reftype = repoConfig.getString(
	"extensions", null, "refsStorage"); //$NON-NLS-1$ //$NON-NLS-2$
	if (repositoryFormatVersion >= 1 && reftype != null) {
	if (StringUtils.equalsIgnoreCase(reftype, "reftree")) { //$NON-NLS-1$
	refs = new RefTreeDatabase(this, new RefDirectory(this));
	} else {
	throw new IOException(JGitText.get().unknownRepositoryFormat);
	}
	} else {
	refs = new RefDirectory(this);
	}

	objectDatabase = new ObjectDirectory(repoConfig, //
	options.getObjectDirectory(), //
	options.getAlternateObjectDirectories(), //
	getFS(), //
	new File(getDirectory(), Constants.SHALLOW));

	if (objectDatabase.exists()) {
	if (repositoryFormatVersion > 1)
	throw new IOException(MessageFormat.format(
	JGitText.get().unknownRepositoryFormat2,
	Long.valueOf(repositoryFormatVersion)));
	}

	if (!isBare())
	snapshot = FileSnapshot.save(getIndexFile());
	}

	private void loadSystemConfig() throws IOException {
	try {
	systemConfig.load();
	} catch (ConfigInvalidException e1) {
	IOException e2 = new IOException(MessageFormat.format(JGitText
	.get().systemConfigFileInvalid, systemConfig.getFile()
	.getAbsolutePath(), e1));
	e2.initCause(e1);
	throw e2;
	}
	}

	private void loadUserConfig() throws IOException {
	try {
	userConfig.load();
	} catch (ConfigInvalidException e1) {
	IOException e2 = new IOException(MessageFormat.format(JGitText
	.get().userConfigFileInvalid, userConfig.getFile()
	.getAbsolutePath(), e1));
	e2.initCause(e1);
	throw e2;
	}
	}

	private void loadRepoConfig() throws IOException {
	try {
	repoConfig.load();
	} catch (ConfigInvalidException e1) {
	IOException e2 = new IOException(JGitText.get().unknownRepositoryFormat);
	e2.initCause(e1);
	throw e2;
	}
	}

	/**
	* Create a new Git repository initializing the necessary files and
	* directories.
	*
	* @param bare
	* if true, a bare repository is created.
	*
	* @throws IOException
	* in case of IO problem
	*/
	@Override
	public void create(boolean bare) throws IOException {
	final FileBasedConfig cfg = getConfig();
	if (cfg.getFile().exists()) {
	throw new IllegalStateException(MessageFormat.format(
	JGitText.get().repositoryAlreadyExists, getDirectory()));
	}
	FileUtils.mkdirs(getDirectory(), true);
	HideDotFiles hideDotFiles = getConfig().getEnum(
	ConfigConstants.CONFIG_CORE_SECTION, null,
	ConfigConstants.CONFIG_KEY_HIDEDOTFILES,
	HideDotFiles.DOTGITONLY);
	if (hideDotFiles != HideDotFiles.FALSE && !isBare()
	&& getDirectory().getName().startsWith(".")) //$NON-NLS-1$
	getFS().setHidden(getDirectory(), true);
	refs.create();
	objectDatabase.create();

	FileUtils.mkdir(new File(getDirectory(), "branches")); //$NON-NLS-1$
	FileUtils.mkdir(new File(getDirectory(), "hooks")); //$NON-NLS-1$

	RefUpdate head = updateRef(Constants.HEAD);
	head.disableRefLog();
	head.link(Constants.R_HEADS + Constants.MASTER);

	final boolean fileMode;
	if (getFS().supportsExecute()) {
	File tmp = File.createTempFile("try", "execute", getDirectory()); //$NON-NLS-1$ //$NON-NLS-2$

	getFS().setExecute(tmp, true);
	final boolean on = getFS().canExecute(tmp);

	getFS().setExecute(tmp, false);
	final boolean off = getFS().canExecute(tmp);
	FileUtils.delete(tmp);

	fileMode = on && !off;
	} else {
	fileMode = false;
	}

	SymLinks symLinks = SymLinks.FALSE;
	if (getFS().supportsSymlinks()) {
	File tmp = new File(getDirectory(), "tmplink"); //$NON-NLS-1$
	try {
	getFS().createSymLink(tmp, "target"); //$NON-NLS-1$
	symLinks = null;
	FileUtils.delete(tmp);
	} catch (IOException e) {
	// Normally a java.nio.file.FileSystemException
	}
	}
	if (symLinks != null)
	cfg.setString(ConfigConstants.CONFIG_CORE_SECTION, null,
	ConfigConstants.CONFIG_KEY_SYMLINKS, symLinks.name()
	.toLowerCase(Locale.ROOT));
	cfg.setInt(ConfigConstants.CONFIG_CORE_SECTION, null,
	ConfigConstants.CONFIG_KEY_REPO_FORMAT_VERSION, 0);
	cfg.setBoolean(ConfigConstants.CONFIG_CORE_SECTION, null,
	ConfigConstants.CONFIG_KEY_FILEMODE, fileMode);
	if (bare)
	cfg.setBoolean(ConfigConstants.CONFIG_CORE_SECTION, null,
	ConfigConstants.CONFIG_KEY_BARE, true);
	cfg.setBoolean(ConfigConstants.CONFIG_CORE_SECTION, null,
	ConfigConstants.CONFIG_KEY_LOGALLREFUPDATES, !bare);
	if (SystemReader.getInstance().isMacOS())
	// Java has no other way
	cfg.setBoolean(ConfigConstants.CONFIG_CORE_SECTION, null,
	ConfigConstants.CONFIG_KEY_PRECOMPOSEUNICODE, true);
	if (!bare) {
	File workTree = getWorkTree();
	if (!getDirectory().getParentFile().equals(workTree)) {
	cfg.setString(ConfigConstants.CONFIG_CORE_SECTION, null,
	ConfigConstants.CONFIG_KEY_WORKTREE, getWorkTree()
	.getAbsolutePath());
	LockFile dotGitLockFile = new LockFile(new File(workTree,
	Constants.DOT_GIT));
	try {
	if (dotGitLockFile.lock()) {
	dotGitLockFile.write(Constants.encode(Constants.GITDIR
	+ getDirectory().getAbsolutePath()));
	dotGitLockFile.commit();
	}
	} finally {
	dotGitLockFile.unlock();
	}
	}
	}
	cfg.save();
	}

	/**
	* @return the directory containing the objects owned by this repository.
	*/
	public File getObjectsDirectory() {
	return objectDatabase.getDirectory();
	}

	/** @return the object database storing this repository's data. */
	@Override
	public ObjectDirectory getObjectDatabase() {
	return objectDatabase;
	}

	/** @return the reference database which stores the reference namespace. */
	@Override
	public RefDatabase getRefDatabase() {
	return refs;
	}

	/** @return the configuration of this repository. */
	@Override
	public FileBasedConfig getConfig() {
	if (systemConfig.isOutdated()) {
	try {
	loadSystemConfig();
	} catch (IOException e) {
	throw new RuntimeException(e);
	}
	}
	if (userConfig.isOutdated()) {
	try {
	loadUserConfig();
	} catch (IOException e) {
	throw new RuntimeException(e);
	}
	}
	if (repoConfig.isOutdated()) {
	try {
	loadRepoConfig();
	} catch (IOException e) {
	throw new RuntimeException(e);
	}
	}
	return repoConfig;
	}

	@Override
	@Nullable
	public String getGitwebDescription() throws IOException {
	String d;
	try {
	d = RawParseUtils.decode(IO.readFully(descriptionFile()));
	} catch (FileNotFoundException err) {
	return null;
	}
	if (d != null) {
	d = d.trim();
	if (d.isEmpty() \|\| UNNAMED.equals(d)) {
	return null;
	}
	}
	return d;
	}

	@Override
	public void setGitwebDescription(@Nullable String description)
	throws IOException {
	String old = getGitwebDescription();
	if (Objects.equals(old, description)) {
	return;
	}

	File path = descriptionFile();
	LockFile lock = new LockFile(path);
	if (!lock.lock()) {
	throw new IOException(MessageFormat.format(JGitText.get().lockError,
	path.getAbsolutePath()));
	}
	try {
	String d = description;
	if (d != null) {
	d = d.trim();
	if (!d.isEmpty()) {
	d += '\n';
	}
	} else {
	d = ""; //$NON-NLS-1$
	}
	lock.write(Constants.encode(d));
	lock.commit();
	} finally {
	lock.unlock();
	}
	}

	private File descriptionFile() {
	return new File(getDirectory(), "description"); //$NON-NLS-1$
	}

	/**
	* Objects known to exist but not expressed by {@link #getAllRefs()}.
	* <p>
	* When a repository borrows objects from another repository, it can
	* advertise that it safely has that other repository's references, without
	* exposing any other details about the other repository. This may help
	* a client trying to push changes avoid pushing more than it needs to.
	*
	* @return unmodifiable collection of other known objects.
	*/
	@Override
	public Set<ObjectId> getAdditionalHaves() {
	HashSet<ObjectId> r = new HashSet<>();
	for (AlternateHandle d : objectDatabase.myAlternates()) {
	if (d instanceof AlternateRepository) {
	Repository repo;

	repo = ((AlternateRepository) d).repository;
	for (Ref ref : repo.getAllRefs().values()) {
	if (ref.getObjectId() != null)
	r.add(ref.getObjectId());
	if (ref.getPeeledObjectId() != null)
	r.add(ref.getPeeledObjectId());
	}
	r.addAll(repo.getAdditionalHaves());
	}
	}
	return r;
	}

	/**
	* Add a single existing pack to the list of available pack files.
	*
	* @param pack
	* path of the pack file to open.
	* @throws IOException
	* index file could not be opened, read, or is not recognized as
	* a Git pack file index.
	*/
	public void openPack(final File pack) throws IOException {
	objectDatabase.openPack(pack);
	}

	@Override
	public void scanForRepoChanges() throws IOException {
	getRefDatabase().getRefs(ALL); // This will look for changes to refs
	detectIndexChanges();
	}

	/** Detect index changes. */
	private void detectIndexChanges() {
	if (isBare())
	return;

	File indexFile = getIndexFile();
	if (snapshot == null)
	snapshot = FileSnapshot.save(indexFile);
	else if (snapshot.isModified(indexFile))
	notifyIndexChanged();
	}

	@Override
	public void notifyIndexChanged() {
	snapshot = FileSnapshot.save(getIndexFile());
	fireEvent(new IndexChangedEvent());
	}

	/**
	* @param refName
	* @return a {@link ReflogReader} for the supplied refname, or null if the
	* named ref does not exist.
	* @throws IOException the ref could not be accessed.
	*/
	@Override
	public ReflogReader getReflogReader(String refName) throws IOException {
	Ref ref = findRef(refName);
	if (ref != null)
	return new ReflogReaderImpl(this, ref.getName());
	return null;
	}

	@Override
	public AttributesNodeProvider createAttributesNodeProvider() {
	return new AttributesNodeProviderImpl(this);
	}

	/**
	* Implementation a {@link AttributesNodeProvider} for a
	* {@link FileRepository}.
	*
	* @author <a href="mailto:arthur.daussy@obeo.fr">Arthur Daussy</a>
	*
	*/
	static class AttributesNodeProviderImpl implements
	AttributesNodeProvider {

	private AttributesNode infoAttributesNode;

	private AttributesNode globalAttributesNode;

	/**
	* Constructor.
	*
	* @param repo
	* {@link Repository} that will provide the attribute nodes.
	*/
	protected AttributesNodeProviderImpl(Repository repo) {
	infoAttributesNode = new InfoAttributesNode(repo);
	globalAttributesNode = new GlobalAttributesNode(repo);
	}

	@Override
	public AttributesNode getInfoAttributesNode() throws IOException {
	if (infoAttributesNode instanceof InfoAttributesNode)
	infoAttributesNode = ((InfoAttributesNode) infoAttributesNode)
	.load();
	return infoAttributesNode;
	}

	@Override
	public AttributesNode getGlobalAttributesNode() throws IOException {
	if (globalAttributesNode instanceof GlobalAttributesNode)
	globalAttributesNode = ((GlobalAttributesNode) globalAttributesNode)
	.load();
	return globalAttributesNode;
	}

	static void loadRulesFromFile(AttributesNode r, File attrs)
	throws FileNotFoundException, IOException {
	if (attrs.exists()) {
	FileInputStream in = new FileInputStream(attrs);
	try {
	r.parse(in);
	} finally {
	in.close();
	}
	}
	}

	}

	@Override
	public void autoGC(ProgressMonitor monitor) {
	GC gc = new GC(this);
	gc.setPackConfig(new PackConfig(this));
	gc.setProgressMonitor(monitor);
	gc.setAuto(true);
	try {
	gc.gc();
	} catch (ParseException \| IOException e) {
	throw new JGitInternalException(JGitText.get().gcFailed, e);
	}
	}
	}