/*
    * Copyright (C) 2008-2009, Google Inc. and others
    *
    * This program and the accompanying materials are made available under the
    * terms of the Eclipse Distribution License v. 1.0 which is available at
    * https://www.eclipse.org/org/documents/edl-v10.php.
    *
    * SPDX-License-Identifier: BSD-3-Clause
    */
  
  package org.eclipse.jgit.dircache;
  
  import static org.junit.Assert.assertEquals;
  import static org.junit.Assert.assertFalse;
  import static org.junit.Assert.assertNotNull;
  import static org.junit.Assert.assertNotSame;
  import static org.junit.Assert.assertNull;
  import static org.junit.Assert.assertSame;
  
  import java.io.IOException;
  
  import org.eclipse.jgit.errors.CorruptObjectException;
  import org.eclipse.jgit.junit.RepositoryTestCase;
  import org.eclipse.jgit.lib.FileMode;
  import org.junit.Test;
  
  public class DirCacheTreeTest extends RepositoryTestCase {
  	@Test
  	public void testEmptyCache_NoCacheTree() throws Exception {
  		final DirCache dc = db.readDirCache();
  		assertNull(dc.getCacheTree(false));
  	}
  
  	@Test
  	public void testEmptyCache_CreateEmptyCacheTree() throws Exception {
  		final DirCache dc = db.readDirCache();
  		final DirCacheTree tree = dc.getCacheTree(true);
  		assertNotNull(tree);
  		assertSame(tree, dc.getCacheTree(false));
  		assertSame(tree, dc.getCacheTree(true));
  		assertEquals("", tree.getNameString());
  		assertEquals("", tree.getPathString());
  		assertEquals(0, tree.getChildCount());
  		assertEquals(0, tree.getEntrySpan());
  		assertFalse(tree.isValid());
  	}
  
  	@Test
  	public void testEmptyCache_Clear_NoCacheTree() throws Exception {
  		final DirCache dc = db.readDirCache();
  		final DirCacheTree tree = dc.getCacheTree(true);
  		assertNotNull(tree);
  		dc.clear();
  		assertNull(dc.getCacheTree(false));
  		assertNotSame(tree, dc.getCacheTree(true));
  	}
  
  	@Test
  	public void testSingleSubtree() throws Exception {
  		final DirCache dc = db.readDirCache();
  
  		final String[] paths = { "a-", "a/b", "a/c", "a/d", "a0b" };
  		final DirCacheEntry[] ents = new DirCacheEntry[paths.length];
  		for (int i = 0; i < paths.length; i++) {
  			ents[i] = new DirCacheEntry(paths[i]);
  			ents[i].setFileMode(FileMode.REGULAR_FILE);
  		}
  		final int aFirst = 1;
  		final int aLast = 3;
  
  		final DirCacheBuilder b = dc.builder();
  		for (DirCacheEntry ent : ents) {
  			b.add(ent);
  		}
  		b.finish();
  
  		assertNull(dc.getCacheTree(false));
  		final DirCacheTree root = dc.getCacheTree(true);
  		assertNotNull(root);
  		assertSame(root, dc.getCacheTree(true));
  		assertEquals("", root.getNameString());
  		assertEquals("", root.getPathString());
  		assertEquals(1, root.getChildCount());
  		assertEquals(dc.getEntryCount(), root.getEntrySpan());
  		assertFalse(root.isValid());
  
  		final DirCacheTree aTree = root.getChild(0);
  		assertNotNull(aTree);
  		assertSame(aTree, root.getChild(0));
  		assertEquals("a", aTree.getNameString());
  		assertEquals("a/", aTree.getPathString());
  		assertEquals(0, aTree.getChildCount());
  		assertEquals(aLast - aFirst + 1, aTree.getEntrySpan());
  		assertFalse(aTree.isValid());
  	}
  
  	@Test
  	public void testTwoLevelSubtree() throws Exception {
  		final DirCache dc = db.readDirCache();
 
 		final String[] paths = { "a-", "a/b", "a/c/e", "a/c/f", "a/d", "a0b" };
 		final DirCacheEntry[] ents = new DirCacheEntry[paths.length];
 		for (int i = 0; i < paths.length; i++) {
 			ents[i] = new DirCacheEntry(paths[i]);
 			ents[i].setFileMode(FileMode.REGULAR_FILE);
 		}
 		final int aFirst = 1;
 		final int aLast = 4;
 		final int acFirst = 2;
 		final int acLast = 3;
 
 		final DirCacheBuilder b = dc.builder();
 		for (DirCacheEntry ent : ents) {
 			b.add(ent);
 		}
 		b.finish();
 
 		assertNull(dc.getCacheTree(false));
 		final DirCacheTree root = dc.getCacheTree(true);
 		assertNotNull(root);
 		assertSame(root, dc.getCacheTree(true));
 		assertEquals("", root.getNameString());
 		assertEquals("", root.getPathString());
 		assertEquals(1, root.getChildCount());
 		assertEquals(dc.getEntryCount(), root.getEntrySpan());
 		assertFalse(root.isValid());
 
 		final DirCacheTree aTree = root.getChild(0);
 		assertNotNull(aTree);
 		assertSame(aTree, root.getChild(0));
 		assertEquals("a", aTree.getNameString());
 		assertEquals("a/", aTree.getPathString());
 		assertEquals(1, aTree.getChildCount());
 		assertEquals(aLast - aFirst + 1, aTree.getEntrySpan());
 		assertFalse(aTree.isValid());
 
 		final DirCacheTree acTree = aTree.getChild(0);
 		assertNotNull(acTree);
 		assertSame(acTree, aTree.getChild(0));
 		assertEquals("c", acTree.getNameString());
 		assertEquals("a/c/", acTree.getPathString());
 		assertEquals(0, acTree.getChildCount());
 		assertEquals(acLast - acFirst + 1, acTree.getEntrySpan());
 		assertFalse(acTree.isValid());
 	}
 
 	/**
 	 * We had bugs related to buffer size in the DirCache. This test creates an
 	 * index larger than the default BufferedInputStream buffer size. This made
 	 * the DirCache unable to read the extensions when index size exceeded the
 	 * buffer size (in some cases at least).
 	 *
 	 * @throws CorruptObjectException
 	 * @throws IOException
 	 */
 	@Test
 	public void testWriteReadTree() throws CorruptObjectException, IOException {
 		final DirCache dc = db.lockDirCache();
 
 		final String A = String.format("a%2000s", "a");
 		final String B = String.format("b%2000s", "b");
 		final String[] paths = { A + "-", A + "-" + B, A + "/" + B, A + "0" + B };
 		final DirCacheEntry[] ents = new DirCacheEntry[paths.length];
 		for (int i = 0; i < paths.length; i++) {
 			ents[i] = new DirCacheEntry(paths[i]);
 			ents[i].setFileMode(FileMode.REGULAR_FILE);
 		}
 
 		final DirCacheBuilder b = dc.builder();
 		for (DirCacheEntry ent : ents) {
 			b.add(ent);
 		}
 
 		b.commit();
 		DirCache read = db.readDirCache();
 
 		assertEquals(paths.length, read.getEntryCount());
 		assertEquals(1, read.getCacheTree(true).getChildCount());
 	}
 }