diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/storage/file/FileSnapshotTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/storage/file/FileSnapshotTest.java new file mode 100644 index 000000000..f90c447ef --- /dev/null +++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/storage/file/FileSnapshotTest.java @@ -0,0 +1,152 @@ +/* + * 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.storage.file; + +import java.io.File; +import java.io.FileOutputStream; +import java.io.IOException; +import java.util.ArrayList; +import java.util.List; + +import org.eclipse.jgit.util.FileUtils; +import org.junit.Before; +import org.junit.Test; +import static org.junit.Assert.*; + +public class FileSnapshotTest { + + private List files = new ArrayList(); + + private final File trash = new File(new File("target"), "trash"); + + @Before + public void tearDown() throws Exception { + FileUtils.delete(trash, FileUtils.RECURSIVE | FileUtils.SKIP_MISSING); + } + + private void waitNextSec(File f) { + long initialLastModified = f.lastModified(); + do { + f.setLastModified(System.currentTimeMillis()); + } while (f.lastModified() == initialLastModified); + } + + /** + * Change data and time stamp. + * + * @throws Exception + */ + @Test + public void testActuallyIsModifiedTrivial() throws Exception { + File f1 = createFile("simple"); + waitNextSec(f1); + FileSnapshot save = FileSnapshot.save(f1); + append(f1, (byte) 'x'); + waitNextSec(f1); + assertTrue(save.isModified(f1)); + } + + /** + * Create a file, wait long enough and verify that it has not been modified. + * 3.5 seconds mean any difference between file system timestamp and system + * clock should be significant. + * + * @throws Exception + */ + @Test + public void testOldFile() throws Exception { + File f1 = createFile("oldfile"); + waitNextSec(f1); + FileSnapshot save = FileSnapshot.save(f1); + Thread.sleep(3500); + assertFalse(save.isModified(f1)); + } + + /** + * 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 { + File f1 = createFile("newfile"); + waitNextSec(f1); + FileSnapshot save = FileSnapshot.save(f1); + Thread.sleep(1500); + assertTrue(save.isModified(f1)); + } + + /** + * Same as {@link #testNewFileWithWait()} but do not wait at all + * + * @throws Exception + */ + @Test + public void testNewFileNoWait() throws Exception { + File f1 = createFile("newfile"); + waitNextSec(f1); + FileSnapshot save = FileSnapshot.save(f1); + Thread.sleep(1500); + assertTrue(save.isModified(f1)); + } + + private File createFile(String string) throws IOException { + trash.mkdirs(); + File f = File.createTempFile(string, "tdat", trash); + files.add(f); + return f; + } + + private void append(File f, byte b) throws IOException { + FileOutputStream os = new FileOutputStream(f, true); + try { + os.write(b); + } finally { + os.close(); + } + } + +} diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/storage/file/FileSnapshot.java b/org.eclipse.jgit/src/org/eclipse/jgit/storage/file/FileSnapshot.java index 87ae57b82..c844404e1 100644 --- a/org.eclipse.jgit/src/org/eclipse/jgit/storage/file/FileSnapshot.java +++ b/org.eclipse.jgit/src/org/eclipse/jgit/storage/file/FileSnapshot.java @@ -45,8 +45,6 @@ import java.io.File; -import org.eclipse.jgit.util.SystemReader; - /** * Caches when a file was last read, making it possible to detect future edits. *

@@ -84,7 +82,7 @@ public class FileSnapshot { * @return the snapshot. */ public static FileSnapshot save(File path) { - final long read = SystemReader.getInstance().getCurrentTime(); + final long read = System.currentTimeMillis(); final long modified = path.lastModified(); return new FileSnapshot(read, modified); } @@ -109,8 +107,8 @@ long lastModified() { } /** - * Check if the path has been modified since the snapshot was saved. - * + * Check if the path may have been modified since the snapshot was saved. + * * @param path * the path the snapshot describes. * @return true if the path needs to be read again. @@ -203,6 +201,12 @@ private boolean isModified(final long currLastModified) { return false; } + // Our lastRead flag may be old, refresh and retry + lastRead = System.currentTimeMillis(); + if (notRacyClean(lastRead)) { + return false; + } + // We last read this path too close to its last observed // modification time. We may have missed a modification. // Scan again, to ensure we still see the same state.