/*
    * Copyright (C) 2012, Roberto Tyley <roberto.tyley@gmail.com>
    *
    * 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,
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  package org.eclipse.jgit.internal.storage.file;
  
  import static java.nio.charset.StandardCharsets.UTF_8;
  import static org.junit.Assert.assertFalse;
  import static org.junit.Assert.assertTrue;
  
  import java.io.File;
  import java.io.FilenameFilter;
  import java.io.IOException;
  import java.io.PrintWriter;
  import java.text.MessageFormat;
  import java.util.Collection;
  import java.util.Collections;
  import java.util.Set;
  import java.util.concurrent.Callable;
  import java.util.concurrent.ExecutorService;
  import java.util.concurrent.Executors;
  import java.util.concurrent.Future;
  
  import org.eclipse.jgit.internal.JGitText;
  import org.eclipse.jgit.junit.RepositoryTestCase;
  import org.eclipse.jgit.lib.ConfigConstants;
  import org.eclipse.jgit.lib.Constants;
  import org.eclipse.jgit.lib.ObjectId;
  import org.eclipse.jgit.revwalk.RevCommit;
  import org.eclipse.jgit.storage.file.FileBasedConfig;
  import org.eclipse.jgit.util.FS;
  import org.junit.Assume;
  import org.junit.Rule;
  import org.junit.Test;
  import org.junit.rules.ExpectedException;
  
  public class ObjectDirectoryTest extends RepositoryTestCase {
  
  	@Rule
  	public ExpectedException expectedEx = ExpectedException.none();
  
  	@Test
  	public void testConcurrentInsertionOfBlobsToTheSameNewFanOutDirectory()
  			throws Exception {
  		ExecutorService e = Executors.newCachedThreadPool();
  		for (int i=0; i < 100; ++i) {
  			ObjectDirectory dir = createBareRepository().getObjectDatabase();
  			for (Future f : e.invokeAll(blobInsertersForTheSameFanOutDir(dir))) {
  				f.get();
  			}
  		}
  	}
  
  	/**
  	 * Test packfile scanning while a gc is done from the outside (different
  	 * process or different Repository instance). This situation occurs e.g. if
  	 * a gerrit server is serving fetch requests while native git is doing a
  	 * garbage collection. The test shows that when core.trustfolderstat==true
  	 * jgit may miss to detect that a new packfile was created. This situation
  	 * is persistent until a new full rescan of the pack directory is triggered.
  	 *
 	 * The test works with two Repository instances working on the same disk
 	 * location. One (db) for all write operations (creating commits, doing gc)
 	 * and another one (receivingDB) which just reads and which in the end shows
 	 * the bug
 	 *
 	 * @throws Exception
 	 */
 	@Test
 	public void testScanningForPackfiles() throws Exception {
 		ObjectId unknownID = ObjectId
 				.fromString("c0ffee09d0b63d694bf49bc1e6847473f42d4a8c");
 		GC gc = new GC(db);
 		gc.setExpireAgeMillis(0);
 		gc.setPackExpireAgeMillis(0);
 
 		// the default repo db is used to create the objects. The receivingDB
 		// repo is used to trigger gc's
 		try (FileRepository receivingDB = new FileRepository(
 				db.getDirectory())) {
 			// set trustfolderstat to true. If set to false the test always
 			// succeeds.
 			FileBasedConfig cfg = receivingDB.getConfig();
 			cfg.setBoolean(ConfigConstants.CONFIG_CORE_SECTION, null,
 					ConfigConstants.CONFIG_KEY_TRUSTFOLDERSTAT, true);
 			cfg.save();
 
 			// setup a repo which has at least one pack file and trigger
 			// scanning of the packs directory
 			ObjectId id = commitFile("file.txt", "test", "master").getId();
 			gc.gc();
 			assertFalse(receivingDB.getObjectDatabase().has(unknownID));
 			assertTrue(receivingDB.getObjectDatabase().hasPackedObject(id));
 
 			// preparations
 			File packsFolder = receivingDB.getObjectDatabase()
 					.getPackDirectory();
 			// prepare creation of a temporary file in the pack folder. This
 			// simulates that a native git gc is happening starting to write
 			// temporary files but has not yet finished
 			File tmpFile = new File(packsFolder, "1.tmp");
 			RevCommit id2 = commitFile("file.txt", "test2", "master");
 			// wait until filesystem timer ticks. This raises probability that
 			// the next statements are executed in the same tick as the
 			// filesystem timer
 			fsTick(null);
 
 			// create a Temp file in the packs folder and trigger a rescan of
 			// the packs folder. This lets receivingDB think it has scanned the
 			// packs folder at the current fs timestamp t1. The following gc
 			// will create new files which have the same timestamp t1 but this
 			// will not update the mtime of the packs folder. Because of that
 			// JGit will not rescan the packs folder later on and fails to see
 			// the pack file created during gc.
 			assertTrue(tmpFile.createNewFile());
 			assertFalse(receivingDB.getObjectDatabase().has(unknownID));
 
 			// trigger a gc. This will create packfiles which have likely the
 			// same mtime than the packfolder
 			gc.gc();
 
 			// To deal with racy-git situations JGit's Filesnapshot class will
 			// report a file/folder potentially dirty if
 			// cachedLastReadTime-cachedLastModificationTime < filesystem
 			// timestamp resolution. This causes JGit to always rescan a file
 			// after modification. But: this was true only if the difference
 			// between current system time and cachedLastModification time was
 			// less than 2500ms. If the modification is more than 2500ms ago we
 			// may have reported a file/folder to be clean although it has not
 			// been rescanned. A bug. To show the bug we sleep for more than
 			// 2500ms
 			Thread.sleep(2600);
 
 			File[] ret = packsFolder.listFiles(new FilenameFilter() {
 				@Override
 				public boolean accept(File dir, String name) {
 					return name.endsWith(".pack");
 				}
 			});
 			assertTrue(ret != null && ret.length == 1);
 			FS fs = db.getFS();
 			Assume.assumeTrue(fs.lastModifiedInstant(tmpFile)
 					.equals(fs.lastModifiedInstant(ret[0])));
 
 			// all objects are in a new packfile but we will not detect it
 			assertFalse(receivingDB.getObjectDatabase().has(unknownID));
 			assertTrue(receivingDB.getObjectDatabase().has(id2));
 		}
 	}
 
 	@Test
 	public void testShallowFile()
 			throws Exception {
 		FileRepository repository = createBareRepository();
 		ObjectDirectory dir = repository.getObjectDatabase();
 
 		String commit = "d3148f9410b071edd4a4c85d2a43d1fa2574b0d2";
 		try (PrintWriter writer = new PrintWriter(
 				new File(repository.getDirectory(), Constants.SHALLOW),
 				UTF_8.name())) {
 			writer.println(commit);
 		}
 		Set<ObjectId> shallowCommits = dir.getShallowCommits();
 		assertTrue(shallowCommits.remove(ObjectId.fromString(commit)));
 		assertTrue(shallowCommits.isEmpty());
 	}
 
 	@Test
 	public void testShallowFileCorrupt()
 			throws Exception {
 		FileRepository repository = createBareRepository();
 		ObjectDirectory dir = repository.getObjectDatabase();
 
 		String commit = "X3148f9410b071edd4a4c85d2a43d1fa2574b0d2";
 		try (PrintWriter writer = new PrintWriter(
 				new File(repository.getDirectory(), Constants.SHALLOW),
 				UTF_8.name())) {
 			writer.println(commit);
 		}
 
 		expectedEx.expect(IOException.class);
 		expectedEx.expectMessage(MessageFormat
 				.format(JGitText.get().badShallowLine, commit));
 		dir.getShallowCommits();
 	}
 
 	private Collection<Callable<ObjectId>> blobInsertersForTheSameFanOutDir(
 			final ObjectDirectory dir) {
 		Callable<ObjectId> callable = new Callable<ObjectId>() {
 			@Override
 			public ObjectId call() throws Exception {
 				return dir.newInserter().insert(Constants.OBJ_BLOB, new byte[0]);
 			}
 		};
 		return Collections.nCopies(4, callable);
 	}
 
 }