@@ -76,7 +84,7 @@ public class FileSnapshot { * file, but only after {@link #isModified(File)} gets invoked. The returned * snapshot contains only invalid status information. */ - public static final FileSnapshot DIRTY = new FileSnapshot(-1, -1); + public static final FileSnapshot DIRTY = new FileSnapshot(-1, -1, UNKNOWN_SIZE); /** * A FileSnapshot that is clean if the file does not exist. @@ -85,7 +93,7 @@ public class FileSnapshot { * file to be clean. {@link #isModified(File)} will return false if the file * path does not exist. */ - public static final FileSnapshot MISSING_FILE = new FileSnapshot(0, 0) { + public static final FileSnapshot MISSING_FILE = new FileSnapshot(0, 0, 0) { @Override public boolean isModified(File path) { return FS.DETECTED.exists(path); @@ -105,12 +113,16 @@ public boolean isModified(File path) { public static FileSnapshot save(File path) { long read = System.currentTimeMillis(); long modified; + long size; try { - modified = FS.DETECTED.lastModified(path); + BasicFileAttributes fileAttributes = FS.DETECTED.fileAttributes(path); + modified = fileAttributes.lastModifiedTime().toMillis(); + size = fileAttributes.size(); } catch (IOException e) { modified = path.lastModified(); + size = path.length(); } - return new FileSnapshot(read, modified); + return new FileSnapshot(read, modified, size); } /** @@ -126,7 +138,7 @@ public static FileSnapshot save(File path) { */ public static FileSnapshot save(long modified) { final long read = System.currentTimeMillis(); - return new FileSnapshot(read, modified); + return new FileSnapshot(read, modified, -1); } /** Last observed modification time of the path. */ @@ -138,10 +150,16 @@ public static FileSnapshot save(long modified) { /** True once {@link #lastRead} is far later than {@link #lastModified}. */ private boolean cannotBeRacilyClean; - private FileSnapshot(long read, long modified) { + /** Underlying file-system size in bytes. + * + * When set to {@link #UNKNOWN_SIZE} the size is not considered for modification checks. */ + private final long size; + + private FileSnapshot(long read, long modified, long size) { this.lastRead = read; this.lastModified = modified; this.cannotBeRacilyClean = notRacyClean(read); + this.size = size; } /** @@ -151,6 +169,13 @@ public long lastModified() { return lastModified; } + /** + * @return file size in bytes of last snapshot update + */ + public long size() { + return size; + } + /** * Check if the path may have been modified since the snapshot was saved. * @@ -160,12 +185,16 @@ public long lastModified() { */ public boolean isModified(File path) { long currLastModified; + long currSize; try { - currLastModified = FS.DETECTED.lastModified(path); + BasicFileAttributes fileAttributes = FS.DETECTED.fileAttributes(path); + currLastModified = fileAttributes.lastModifiedTime().toMillis(); + currSize = fileAttributes.size(); } catch (IOException e) { currLastModified = path.lastModified(); + currSize = path.length(); } - return isModified(currLastModified); + return (currSize != UNKNOWN_SIZE && currSize != size) || isModified(currLastModified); } /** diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/ObjectDirectory.java b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/ObjectDirectory.java index 00e39533b..e1934a13d 100644 --- a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/ObjectDirectory.java +++ b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/ObjectDirectory.java @@ -841,13 +841,13 @@ private PackList scanPacksImpl(final PackList old) { } final String packName = base + PACK.getExtension(); + final File packFile = new File(packDirectory, packName); final PackFile oldPack = forReuse.remove(packName); - if (oldPack != null) { + if (oldPack != null && oldPack.getFileSnapshot().isModified(packFile)) { list.add(oldPack); continue; } - final File packFile = new File(packDirectory, packName); list.add(new PackFile(packFile, extensions)); foundNew = true; } diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/PackFile.java b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/PackFile.java index 0611d3e85..e7db11d08 100644 --- a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/PackFile.java +++ b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/PackFile.java @@ -131,6 +131,8 @@ public int compare(final PackFile a, final PackFile b) { int packLastModified; + private FileSnapshot fileSnapshot; + private volatile boolean invalid; private boolean invalidBitmap; @@ -164,7 +166,8 @@ public int compare(final PackFile a, final PackFile b) { */ public PackFile(final File packFile, int extensions) { this.packFile = packFile; - this.packLastModified = (int) (packFile.lastModified() >> 10); + this.fileSnapshot = FileSnapshot.save(packFile); + this.packLastModified = (int) (fileSnapshot.lastModified() >> 10); this.extensions = extensions; // Multiply by 31 here so we can more directly combine with another @@ -338,6 +341,16 @@ ObjectId findObjectForOffset(final long offset) throws IOException { return getReverseIdx().findObject(offset); } + /** + * Return the @{@link FileSnapshot} associated to the underlying packfile + * that has been used when the object was created. + * + * @return the packfile @{@link FileSnapshot} that the object is loaded from. + */ + FileSnapshot getFileSnapshot() { + return fileSnapshot; + } + private final byte[] decompress(final long position, final int sz, final WindowCursor curs) throws IOException, DataFormatException { byte[] dstbuf; @@ -633,9 +646,10 @@ synchronized boolean endWindowCache() { } private void doOpen() throws IOException { + if (invalid) { + throw new PackInvalidException(packFile); + } try { - if (invalid) - throw new PackInvalidException(packFile); synchronized (readLock) { fd = new RandomAccessFile(packFile, "r"); //$NON-NLS-1$ length = fd.length(); @@ -691,6 +705,14 @@ private void doClose() { ByteArrayWindow read(final long pos, int size) throws IOException { synchronized (readLock) { + if (invalid || fd == null) { + // Due to concurrency between a read and another packfile invalidation thread + // one thread could come up to this point and then fail with NPE. + // Detect the situation and throw a proper exception so that can be properly + // managed by the main packfile search loop and the Git client won't receive + // any failures. + throw new PackInvalidException(packFile); + } if (length < pos + size) size = (int) (length - pos); final byte[] buf = new byte[size]; diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/util/FS.java b/org.eclipse.jgit/src/org/eclipse/jgit/util/FS.java index 8d4e5e52a..183bf460c 100644 --- a/org.eclipse.jgit/src/org/eclipse/jgit/util/FS.java +++ b/org.eclipse.jgit/src/org/eclipse/jgit/util/FS.java @@ -55,6 +55,7 @@ import java.nio.charset.Charset; import java.nio.file.Files; import java.nio.file.Path; +import java.nio.file.attribute.BasicFileAttributes; import java.security.AccessController; import java.security.PrivilegedAction; import java.text.MessageFormat; @@ -420,6 +421,19 @@ public FS setUserHome(File path) { */ public abstract boolean retryFailedLockFileCommit(); + /** + * Return all the attributes of a file, without following symbolic links. + * + * @param file + * @return {@link BasicFileAttributes} of the file + * @throws IOException in case of any I/O errors accessing the file + * + * @since 4.5.6 + */ + public BasicFileAttributes fileAttributes(File file) throws IOException { + return FileUtils.fileAttributes(file); + } + /** * Determine the user's home directory (location where preferences are). * diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/util/FileUtils.java b/org.eclipse.jgit/src/org/eclipse/jgit/util/FileUtils.java index 1f20e9700..31cfe4245 100644 --- a/org.eclipse.jgit/src/org/eclipse/jgit/util/FileUtils.java +++ b/org.eclipse.jgit/src/org/eclipse/jgit/util/FileUtils.java @@ -586,6 +586,19 @@ static long lastModified(File file) throws IOException { .toMillis(); } + /** + * Return all the attributes of a file, without following symbolic links. + * + * @param file + * @return {@link BasicFileAttributes} of the file + * @throws IOException in case of any I/O errors accessing the file + * + * @since 4.5.6 + */ + static BasicFileAttributes fileAttributes(File file) throws IOException { + return Files.readAttributes(file.toPath(), BasicFileAttributes.class, LinkOption.NOFOLLOW_LINKS); + } + /** * @param file * @param time