Add exception class for when locking a file fails

This will allows calling classes to handle lock failures
without checking against the message and will also provide
access to the file that could not be locked.

Change-Id: I95bc59e1330a7af71ae3b0485c4516299193f504

org.eclipse.jgit/resources/org/eclipse/jgit/JGitText.properties

@@ -56,7 +56,6 @@ cannotExecute=cannot execute: {0}
 cannotGet=Cannot get {0}
 cannotListRefs=cannot list refs
 cannotLock=Cannot lock {0}
-cannotLockFile=Cannot lock file {0}
 cannotLockPackIn=Cannot lock pack in {0}
 cannotMatchOnEmptyString=Cannot match on empty string.
 cannotMoveIndexTo=Cannot move index to {0}

org.eclipse.jgit/src/org/eclipse/jgit/JGitText.java

@@ -116,7 +116,6 @@ public class JGitText extends TranslationBundle {
 	/***/ public String cannotGet;
 	/***/ public String cannotListRefs;
 	/***/ public String cannotLock;
-	/***/ public String cannotLockFile;
 	/***/ public String cannotLockPackIn;
 	/***/ public String cannotMatchOnEmptyString;
 	/***/ public String cannotMoveIndexTo;

org.eclipse.jgit/src/org/eclipse/jgit/dircache/DirCache.java

@@ -62,6 +62,7 @@ import java.util.Arrays;
 import java.util.Comparator;
 
 import org.eclipse.jgit.JGitText;
+import org.eclipse.jgit.errors.LockFailedException;
 import org.eclipse.jgit.errors.CorruptObjectException;
 import org.eclipse.jgit.errors.UnmergedPathException;
 import org.eclipse.jgit.events.IndexChangedEvent;
@@ -190,7 +191,7 @@ public class DirCache {
 			throws CorruptObjectException, IOException {
 		final DirCache c = new DirCache(indexLocation, fs);
 		if (!c.lock())
-			throw new IOException(MessageFormat.format(JGitText.get().cannotLock, indexLocation));
+			throw new LockFailedException(indexLocation);
 
 		try {
 			c.read();

org.eclipse.jgit/src/org/eclipse/jgit/errors/LockFailedException.java

@@ -0,0 +1,90 @@
+/*
+ * Copyright (C) 2011, GitHub Inc.
+ * 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.errors;
+
+import java.io.File;
+import java.io.IOException;
+import java.text.MessageFormat;
+
+import org.eclipse.jgit.JGitText;
+
+/**
+ * An exception occurring when a file cannot be locked
+ */
+public class LockFailedException extends IOException {
+	private static final long serialVersionUID = 1L;
+
+	private File file;
+
+	/**
+	 * Construct a CannotLockException for the given file and message
+	 *
+	 * @param file
+	 *            file that could not be locked
+	 * @param message
+	 *            exception message
+	 */
+	public LockFailedException(File file, String message) {
+		super(message);
+		this.file = file;
+	}
+
+	/**
+	 * Construct a CannotLockException for the given file
+	 *
+	 * @param file
+	 *            file that could not be locked
+	 */
+	public LockFailedException(File file) {
+		this(file, MessageFormat.format(JGitText.get().cannotLock, file));
+	}
+
+	/**
+	 * Get the file that could not be locked
+	 *
+	 * @return file
+	 */
+	public File getFile() {
+		return file;
+	}
+}

org.eclipse.jgit/src/org/eclipse/jgit/storage/file/FileBasedConfig.java

@@ -55,6 +55,7 @@ import java.io.IOException;
 import java.text.MessageFormat;
 
 import org.eclipse.jgit.JGitText;
+import org.eclipse.jgit.errors.LockFailedException;
 import org.eclipse.jgit.errors.ConfigInvalidException;
 import org.eclipse.jgit.lib.Config;
 import org.eclipse.jgit.lib.Constants;
@@ -172,7 +173,7 @@ public class FileBasedConfig extends StoredConfig {
 		final byte[] out = Constants.encode(toText());
 		final LockFile lf = new LockFile(getFile(), fs);
 		if (!lf.lock())
-			throw new IOException(MessageFormat.format(JGitText.get().cannotLockFile, getFile()));
+			throw new LockFailedException(getFile());
 		try {
 			lf.setNeedSnapshot(true);
 			lf.write(out);

org.eclipse.jgit/src/org/eclipse/jgit/storage/file/ObjectDirectoryPackParser.java

@@ -58,6 +58,7 @@ import java.util.zip.CRC32;
 import java.util.zip.Deflater;
 
 import org.eclipse.jgit.JGitText;
+import org.eclipse.jgit.errors.LockFailedException;
 import org.eclipse.jgit.lib.AnyObjectId;
 import org.eclipse.jgit.lib.Constants;
 import org.eclipse.jgit.lib.CoreConfig;
@@ -452,8 +453,9 @@ public class ObjectDirectoryPackParser extends PackParser {
 			//
 			try {
 				if (!keep.lock(lockMessage))
-					throw new IOException(MessageFormat.format(
-							JGitText.get().cannotLockPackIn, finalPack));
+					throw new LockFailedException(finalPack,
+							MessageFormat.format(
+									JGitText.get().cannotLockPackIn, finalPack));
 			} catch (IOException e) {
 				cleanupTemporaryFiles();
 				throw e;

org.eclipse.jgit/src/org/eclipse/jgit/storage/file/RefDirectory.java

@@ -78,6 +78,7 @@ import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.atomic.AtomicReference;
 
 import org.eclipse.jgit.JGitText;
+import org.eclipse.jgit.errors.LockFailedException;
 import org.eclipse.jgit.errors.MissingObjectException;
 import org.eclipse.jgit.errors.ObjectWritingException;
 import org.eclipse.jgit.events.RefsChangedEvent;
@@ -562,8 +563,7 @@ public class RefDirectory extends RefDatabase {
 			LockFile lck = new LockFile(packedRefsFile,
 					update.getRepository().getFS());
 			if (!lck.lock())
-				throw new IOException(MessageFormat.format(
-					JGitText.get().cannotLockFile, packedRefsFile));
+				throw new LockFailedException(packedRefsFile);
 			try {
 				PackedRefList cur = readPackedRefs();
 				int idx = cur.find(name);