Merge branch 'stable-5.5' into stable-5.6

* stable-5.5:
  Add missing @since tags
  Remove unused import in ApacheSshTest
  Update maven plugins
  Ignore missing javadoc in test bundles
  storage: file: De-duplicate File.exists()+File.isFile()
  RefDirectory.scanRef: Re-use file existence check done in snapshot creation
  FileSnapshot: Lazy load file store attributes cache
  Update eclipse-jarsigner-plugin to 1.3.2
  Fix p2 repository URLs

Change-Id: I007e92c12fde8d765b75f103e9d530aa0834b7d7

3 files changed, 35 insertions, 9 deletions

diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/FileSnapshot.java b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/FileSnapshot.java
index 8650ebfe29..e4ee53e0a1 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/FileSnapshot.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/FileSnapshot.java
@@ -218,6 +218,12 @@ public class FileSnapshot {
 	private FileStoreAttributes fileStoreAttributeCache;
 
 	/**
+	 * if {@code true} read filesystem time resolution from configuration file
+	 * otherwise use fallback resolution
+	 */
+	private boolean useConfig;
+
+	/**
 	 * Object that uniquely identifies the given file, or {@code
 	 * null} if a file key is not available
 	 */
@@ -253,9 +259,7 @@ public class FileSnapshot {
 	protected FileSnapshot(File file, boolean useConfig) {
 		this.file = file;
 		this.lastRead = Instant.now();
-		this.fileStoreAttributeCache = useConfig
-				? FS.getFileStoreAttributes(file.toPath().getParent())
-				: FALLBACK_FILESTORE_ATTRIBUTES;
+		this.useConfig = useConfig;
 		BasicFileAttributes fileAttributes = null;
 		try {
 			fileAttributes = FS.DETECTED.fileAttributes(file);
@@ -399,7 +403,7 @@ public class FileSnapshot {
 	 *             if sleep was interrupted
 	 */
 	public void waitUntilNotRacy() throws InterruptedException {
-		long timestampResolution = fileStoreAttributeCache
+		long timestampResolution = fileStoreAttributeCache()
 				.getFsTimestampResolution().toNanos();
 		while (isRacyClean(Instant.now())) {
 			TimeUnit.NANOSECONDS.sleep(timestampResolution);
@@ -436,6 +440,15 @@ public class FileSnapshot {
 		return equals(other);
 	}
 
+	/**
+	 * Check if the file exists
+	 *
+	 * @return true if the file exists
+	 */
+	public boolean fileExists() {
+		return !MISSING_FILEKEY.equals(this.fileKey);
+	}
+
 	/** {@inheritDoc} */
 	@Override
 	public int hashCode() {
@@ -520,10 +533,10 @@ public class FileSnapshot {
 	}
 
 	private long getEffectiveRacyThreshold() {
-		long timestampResolution = fileStoreAttributeCache
+		long timestampResolution = fileStoreAttributeCache()
 				.getFsTimestampResolution().toNanos();
-		long minRacyInterval = fileStoreAttributeCache.getMinimalRacyInterval()
-				.toNanos();
+		long minRacyInterval = fileStoreAttributeCache()
+				.getMinimalRacyInterval().toNanos();
 		long max = Math.max(timestampResolution, minRacyInterval);
 		// safety margin: factor 2.5 below 100ms otherwise 1.25
 		return max < 100_000_000L ? max * 5 / 2 : max * 5 / 4;
@@ -583,4 +596,13 @@ public class FileSnapshot {
 		}
 		return changed;
 	}
+
+	private FileStoreAttributes fileStoreAttributeCache() {
+		if (fileStoreAttributeCache == null) {
+			fileStoreAttributeCache = useConfig
+					? FS.getFileStoreAttributes(file.toPath().getParent())
+					: FALLBACK_FILESTORE_ATTRIBUTES;
+		}
+		return fileStoreAttributeCache;
+	}
 }
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/ObjectDirectoryPackParser.java b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/ObjectDirectoryPackParser.java
index 7d31673566..8fa683f5ee 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/ObjectDirectoryPackParser.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/ObjectDirectoryPackParser.java
@@ -184,7 +184,7 @@ public class ObjectDirectoryPackParser extends PackParser {
 		String p = pack.getAbsolutePath();
 		String i = p.substring(0, p.length() - ".pack".length()) + ".idx"; //$NON-NLS-1$ //$NON-NLS-2$
 		File idx = new File(i);
-		if (idx.exists() && idx.isFile())
+		if (idx.isFile())
 			size += idx.length();
 		return size;
 	}
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/RefDirectory.java b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/RefDirectory.java
index 9476d35475..ae8fe0f562 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/RefDirectory.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/RefDirectory.java
@@ -1122,10 +1122,14 @@ public class RefDirectory extends RefDatabase {
 		final int limit = 4096;
 		final byte[] buf;
 		FileSnapshot otherSnapshot = FileSnapshot.save(path);
+		if (!otherSnapshot.fileExists()) {
+			return null;
+		}
+
 		try {
 			buf = IO.readSome(path, limit);
 		} catch (FileNotFoundException noFile) {
-			if (path.exists() && path.isFile()) {
+			if (path.isFile()) {
 				throw noFile;
 			}
 			return null; // doesn't exist or no file; not a reference.