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- /*
- * Copyright (C) 2010, Robin Rosenberg
- * 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.junit.JGitTestUtil.read;
- import static org.eclipse.jgit.junit.JGitTestUtil.write;
- import static org.junit.Assert.assertEquals;
- import static org.junit.Assert.assertFalse;
- import static org.junit.Assert.assertTrue;
- import static org.junit.Assert.fail;
-
- import java.io.File;
- import java.io.IOException;
- import java.io.OutputStream;
- import java.nio.file.Files;
- import java.nio.file.Path;
- import java.nio.file.StandardCopyOption;
- import java.nio.file.StandardOpenOption;
- import java.nio.file.attribute.FileTime;
- import java.time.Duration;
- import java.time.Instant;
- import java.util.ArrayList;
- import java.util.concurrent.TimeUnit;
-
- import org.eclipse.jgit.junit.MockSystemReader;
- import org.eclipse.jgit.util.FS;
- import org.eclipse.jgit.util.FS.FileStoreAttributes;
- import org.eclipse.jgit.util.FileUtils;
- import org.eclipse.jgit.util.Stats;
- import org.eclipse.jgit.util.SystemReader;
- import org.junit.After;
- import org.junit.Assume;
- import org.junit.Before;
- import org.junit.Test;
- import org.slf4j.Logger;
- import org.slf4j.LoggerFactory;
-
- public class FileSnapshotTest {
- private static final Logger LOG = LoggerFactory
- .getLogger(FileSnapshotTest.class);
-
- private Path trash;
-
- private FileStoreAttributes fsAttrCache;
-
- @Before
- public void setUp() throws Exception {
- SystemReader.setInstance(new MockSystemReader());
- trash = Files.createTempDirectory("tmp_");
- // measure timer resolution before the test to avoid time critical tests
- // are affected by time needed for measurement
- fsAttrCache = FS
- .getFileStoreAttributes(trash.getParent());
- }
-
- @Before
- @After
- public void tearDown() throws Exception {
- FileUtils.delete(trash.toFile(),
- FileUtils.RECURSIVE | FileUtils.SKIP_MISSING);
- }
-
- private static void waitNextTick(Path f) throws IOException {
- Instant initialLastModified = FS.DETECTED.lastModifiedInstant(f);
- do {
- FS.DETECTED.setLastModified(f, Instant.now());
- } while (FS.DETECTED.lastModifiedInstant(f)
- .equals(initialLastModified));
- }
-
- /**
- * Change data and time stamp.
- *
- * @throws Exception
- */
- @Test
- public void testActuallyIsModifiedTrivial() throws Exception {
- Path f1 = createFile("simple");
- waitNextTick(f1);
- FileSnapshot save = FileSnapshot.save(f1.toFile());
- append(f1, (byte) 'x');
- waitNextTick(f1);
- assertTrue(save.isModified(f1.toFile()));
- }
-
- /**
- * Create a file, but don't wait long enough for the difference between file
- * system clock and system clock to be significant. Assume the file may have
- * been modified. It may have been, but the clock alone cannot determine
- * this
- *
- * @throws Exception
- */
- @Test
- public void testNewFileWithWait() throws Exception {
- // if filesystem timestamp resolution is high the snapshot won't be
- // racily clean
- Assume.assumeTrue(
- fsAttrCache.getFsTimestampResolution()
- .compareTo(Duration.ofMillis(10)) > 0);
- Path f1 = createFile("newfile");
- waitNextTick(f1);
- FileSnapshot save = FileSnapshot.save(f1.toFile());
- TimeUnit.NANOSECONDS.sleep(
- fsAttrCache.getFsTimestampResolution().dividedBy(2).toNanos());
- assertTrue(save.isModified(f1.toFile()));
- }
-
- /**
- * Same as {@link #testNewFileWithWait()} but do not wait at all
- *
- * @throws Exception
- */
- @Test
- public void testNewFileNoWait() throws Exception {
- // if filesystem timestamp resolution is smaller than time needed to
- // create a file and FileSnapshot the snapshot won't be racily clean
- Assume.assumeTrue(fsAttrCache.getFsTimestampResolution()
- .compareTo(Duration.ofMillis(10)) > 0);
- for (int i = 0; i < 50; i++) {
- Instant start = Instant.now();
- Path f1 = createFile("newfile");
- FileSnapshot save = FileSnapshot.save(f1.toFile());
- Duration res = FS.getFileStoreAttributes(f1)
- .getFsTimestampResolution();
- Instant end = Instant.now();
- if (Duration.between(start, end)
- .compareTo(res.multipliedBy(2)) > 0) {
- // This test is racy: under load, there may be a delay between createFile() and
- // FileSnapshot.save(). This can stretch the time between the read TS and FS
- // creation TS to the point that it exceeds the FS granularity, and we
- // conclude it cannot be racily clean, and therefore must be really clean.
- //
- // This should be relatively uncommon.
- continue;
- }
- // The file wasn't really modified, but it looks just like a "maybe racily clean"
- // file.
- assertTrue(save.isModified(f1.toFile()));
- return;
- }
- fail("too much load for this test");
- }
-
- /**
- * Simulate packfile replacement in same file which may occur if set of
- * objects in the pack is the same but pack config was different. On Posix
- * filesystems this should change the inode (filekey in java.nio
- * terminology).
- *
- * @throws Exception
- */
- @Test
- public void testSimulatePackfileReplacement() throws Exception {
- Assume.assumeFalse(SystemReader.getInstance().isWindows());
- Path f1 = createFile("file"); // inode y
- Path f2 = createFile("fool"); // Guarantees new inode x
- // wait on f2 since this method resets lastModified of the file
- // and leaves lastModified of f1 untouched
- waitNextTick(f2);
- waitNextTick(f2);
- FileTime timestamp = Files.getLastModifiedTime(f1);
- FileSnapshot save = FileSnapshot.save(f1.toFile());
- Files.move(f2, f1, // Now "file" is inode x
- StandardCopyOption.REPLACE_EXISTING,
- StandardCopyOption.ATOMIC_MOVE);
- Files.setLastModifiedTime(f1, timestamp);
- assertTrue(save.isModified(f1.toFile()));
- assertTrue("unexpected change of fileKey", save.wasFileKeyChanged());
- assertFalse("unexpected size change", save.wasSizeChanged());
- assertFalse("unexpected lastModified change",
- save.wasLastModifiedChanged());
- assertFalse("lastModified was unexpectedly racily clean",
- save.wasLastModifiedRacilyClean());
- }
-
- /**
- * Append a character to a file to change its size and set original
- * lastModified
- *
- * @throws Exception
- */
- @Test
- public void testFileSizeChanged() throws Exception {
- Path f = createFile("file");
- FileTime timestamp = Files.getLastModifiedTime(f);
- FileSnapshot save = FileSnapshot.save(f.toFile());
- append(f, (byte) 'x');
- Files.setLastModifiedTime(f, timestamp);
- assertTrue(save.isModified(f.toFile()));
- assertTrue(save.wasSizeChanged());
- }
-
- @Test
- public void fileSnapshotEquals() throws Exception {
- // 0 sized FileSnapshot.
- FileSnapshot fs1 = FileSnapshot.MISSING_FILE;
- // UNKNOWN_SIZE FileSnapshot.
- FileSnapshot fs2 = FileSnapshot.save(fs1.lastModifiedInstant());
-
- assertTrue(fs1.equals(fs2));
- assertTrue(fs2.equals(fs1));
- }
-
- @SuppressWarnings("boxing")
- @Test
- public void detectFileModified() throws IOException {
- int failures = 0;
- long racyNanos = 0;
- final int COUNT = 10000;
- ArrayList<Long> deltas = new ArrayList<>();
- File f = createFile("test").toFile();
- for (int i = 0; i < COUNT; i++) {
- write(f, "a");
- FileSnapshot snapshot = FileSnapshot.save(f);
- assertEquals("file should contain 'a'", "a", read(f));
- write(f, "b");
- if (!snapshot.isModified(f)) {
- deltas.add(snapshot.lastDelta());
- racyNanos = snapshot.lastRacyThreshold();
- failures++;
- }
- assertEquals("file should contain 'b'", "b", read(f));
- }
- if (failures > 0) {
- Stats stats = new Stats();
- LOG.debug(
- "delta [ns] since modification FileSnapshot failed to detect");
- for (Long d : deltas) {
- stats.add(d);
- LOG.debug(String.format("%,d", d));
- }
- LOG.error(
- "count, failures, eff. racy threshold [ns], delta min [ns],"
- + " delta max [ns], delta avg [ns],"
- + " delta stddev [ns]");
- LOG.error(String.format(
- "%,d, %,d, %,d, %,.0f, %,.0f, %,.0f, %,.0f", COUNT,
- failures, racyNanos, stats.min(), stats.max(),
- stats.avg(), stats.stddev()));
- }
- assertTrue(
- String.format(
- "FileSnapshot: failures to detect file modifications"
- + " %d out of %d\n"
- + "timestamp resolution %d µs"
- + " min racy threshold %d µs"
- , failures, COUNT,
- fsAttrCache.getFsTimestampResolution().toNanos() / 1000,
- fsAttrCache.getMinimalRacyInterval().toNanos() / 1000),
- failures == 0);
- }
-
- private Path createFile(String string) throws IOException {
- Files.createDirectories(trash);
- return Files.createTempFile(trash, string, "tdat");
- }
-
- private static void append(Path f, byte b) throws IOException {
- try (OutputStream os = Files.newOutputStream(f,
- StandardOpenOption.APPEND)) {
- os.write(b);
- }
- }
-
- }
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