Add delete support to FS

Change-Id: Ib6f6fd5ef4a0c9b2062445ac4a0c9d1131e401bf

org.eclipse.jgit.java7/src/org/eclipse/jgit/util/FS_POSIX_Java7.java

@@ -106,6 +106,11 @@ public class FS_POSIX_Java7 extends FS_POSIX {
 		FileUtil.setLastModified(path, time);
 	}
 
+	@Override
+	public void delete(File path) throws IOException {
+		FileUtil.delete(path);
+	}
+
 	@Override
 	public long length(File f) throws IOException {
 		return FileUtil.getLength(f);

org.eclipse.jgit.java7/src/org/eclipse/jgit/util/FS_Win32_Java7.java

@@ -107,6 +107,11 @@ public class FS_Win32_Java7 extends FS_Win32 {
 		FileUtil.setLastModified(path, time);
 	}
 
+	@Override
+	public void delete(File path) throws IOException {
+		FileUtil.delete(path);
+	}
+
 	@Override
 	public long length(File f) throws IOException {
 		return FileUtil.getLength(f);

org.eclipse.jgit.java7/src/org/eclipse/jgit/util/FS_Win32_Java7Cygwin.java

@@ -83,6 +83,11 @@ public class FS_Win32_Java7Cygwin extends FS_Win32_Cygwin {
 		FileUtil.setLastModified(path, time);
 	}
 
+	@Override
+	public void delete(File path) throws IOException {
+		FileUtil.delete(path);
+	}
+
 	@Override
 	public long length(File f) throws IOException {
 		return FileUtil.getLength(f);

org.eclipse.jgit.java7/src/org/eclipse/jgit/util/FileUtil.java

@@ -139,4 +139,9 @@ class FileUtil {
 		return path.setExecutable(executable);
 	}
 
+	public static void delete(File path) throws IOException {
+		Path nioPath = path.toPath();
+		Files.delete(nioPath);
+	}
+
 }

org.eclipse.jgit/src/org/eclipse/jgit/util/FS.java

@@ -50,6 +50,7 @@ import java.io.InputStream;
 import java.io.InputStreamReader;
 import java.security.AccessController;
 import java.security.PrivilegedAction;
+import java.text.MessageFormat;
 import java.util.Arrays;
 import java.util.concurrent.atomic.AtomicBoolean;
 
@@ -272,6 +273,20 @@ public abstract class FS {
 		return path.length();
 	}
 
+	/**
+	 * Delete a file. Throws an exception if delete fails.
+	 *
+	 * @param f
+	 * @throws IOException
+	 *             this may be a Java7 subclass with detailed information
+	 * @since 3.3
+	 */
+	public void delete(File f) throws IOException {
+		if (!f.delete())
+			throw new IOException(MessageFormat.format(
+					JGitText.get().deleteFileFailed, f.getAbsolutePath()));
+	}
+
 	/**
 	 * Resolve this file to its actual path name that the JRE can use.
 	 * <p>