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- /*
- * Copyright (C) 2017 Two Sigma Open Source
- * 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 java.nio.charset.StandardCharsets.UTF_8;
-
- import java.io.File;
- import java.io.IOException;
- import java.nio.file.Files;
- import java.nio.file.NoSuchFileException;
- import java.nio.file.attribute.FileTime;
- import java.text.ParseException;
- import java.time.Instant;
-
- import org.eclipse.jgit.api.errors.JGitInternalException;
- import org.eclipse.jgit.lib.ConfigConstants;
- import org.eclipse.jgit.util.FileUtils;
- import org.eclipse.jgit.util.GitDateParser;
- import org.eclipse.jgit.util.SystemReader;
-
- /**
- * This class manages the gc.log file for a {@link FileRepository}.
- */
- class GcLog {
- private final FileRepository repo;
-
- private final File logFile;
-
- private final LockFile lock;
-
- private Instant gcLogExpire;
-
- private static final String LOG_EXPIRY_DEFAULT = "1.day.ago"; //$NON-NLS-1$
-
- private boolean nonEmpty = false;
-
- /**
- * Construct a GcLog object for a {@link FileRepository}
- *
- * @param repo
- * the repository
- */
- GcLog(FileRepository repo) {
- this.repo = repo;
- logFile = new File(repo.getDirectory(), "gc.log"); //$NON-NLS-1$
- lock = new LockFile(logFile);
- }
-
- private Instant getLogExpiry() throws ParseException {
- if (gcLogExpire == null) {
- String logExpiryStr = repo.getConfig().getString(
- ConfigConstants.CONFIG_GC_SECTION, null,
- ConfigConstants.CONFIG_KEY_LOGEXPIRY);
- if (logExpiryStr == null) {
- logExpiryStr = LOG_EXPIRY_DEFAULT;
- }
- gcLogExpire = GitDateParser.parse(logExpiryStr, null,
- SystemReader.getInstance().getLocale()).toInstant();
- }
- return gcLogExpire;
- }
-
- private boolean autoGcBlockedByOldLockFile() {
- try {
- FileTime lastModified = Files.getLastModifiedTime(FileUtils.toPath(logFile));
- if (lastModified.toInstant().compareTo(getLogExpiry()) > 0) {
- // There is an existing log file, which is too recent to ignore
- return true;
- }
- } catch (NoSuchFileException e) {
- // No existing log file, OK.
- } catch (IOException | ParseException e) {
- throw new JGitInternalException(e.getMessage(), e);
- }
- return false;
- }
-
- /**
- * Lock the GC log file for updates
- *
- * @return {@code true} if we hold the lock
- */
- boolean lock() {
- try {
- if (!lock.lock()) {
- return false;
- }
- } catch (IOException e) {
- throw new JGitInternalException(e.getMessage(), e);
- }
- if (autoGcBlockedByOldLockFile()) {
- lock.unlock();
- return false;
- }
- return true;
- }
-
- /**
- * Unlock (roll back) the GC log lock
- */
- void unlock() {
- lock.unlock();
- }
-
- /**
- * Commit changes to the gc log, if there have been any writes. Otherwise,
- * just unlock and delete the existing file (if any)
- *
- * @return true if committing (or unlocking/deleting) succeeds.
- */
- boolean commit() {
- if (nonEmpty) {
- return lock.commit();
- } else {
- logFile.delete();
- lock.unlock();
- return true;
- }
- }
-
- /**
- * Write to the pending gc log. Content will be committed upon a call to
- * commit()
- *
- * @param content
- * The content to write
- * @throws IOException
- */
- void write(String content) throws IOException {
- if (content.length() > 0) {
- nonEmpty = true;
- }
- lock.write(content.getBytes(UTF_8));
- }
- }
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