pgm: add option to configure if convert-ref-storage should create backup

Change-Id: I926f116797508a5982961dfd30c2f765d9536eee
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

org.eclipse.jgit.pgm/resources/org/eclipse/jgit/pgm/internal/CLIText.properties

@@ -5,6 +5,8 @@
 #
 # default meta variable defined in the org.kohsuke.args4j.spi.StringOptionHandler
 VAL=VAL
+# default meta variable defined in the org.kohsuke.args4j.spi.ExplicitBooleanOptionHandler
+VALUE=VAL
 # default meta variable defined in the org.kohsuke.args4j.spi.StopOptionHandler
 ARGUMENTS=ARGUMENTS
 # default meta variable defined in the org.kohsuke.args4j.spi.OneArgumentOptionHandler
@@ -327,6 +329,7 @@ usage_configLocal=use local configuration in .git/config
 usage_configSystem=use system-wide configuration in $(prefix)/etc/gitconfig
 usage_configureTheServiceInDaemonServicename=configure the service in daemon.servicename
 usage_convertRefStorage=Convert ref storage to reftable
+usage_convertRefStorageBackup=Create backup of old ref storage format
 usage_convertRefStorageFormat=Format to convert to (reftable or refdir)
 usage_createBranchAndCheckout=create branch and check out
 usage_deleteBranchEvenIfNotMerged=delete branch (even if not merged)

org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/ConvertRefStorage.java

@@ -45,6 +45,7 @@ package org.eclipse.jgit.pgm;
 
 import org.eclipse.jgit.internal.storage.file.FileRepository;
 import org.kohsuke.args4j.Option;
+import org.kohsuke.args4j.spi.ExplicitBooleanOptionHandler;
 
 @Command(common = true, usage = "usage_convertRefStorage")
 class ConvertRefStorage extends TextBuiltin {
@@ -52,9 +53,13 @@ class ConvertRefStorage extends TextBuiltin {
 	@Option(name = "--format", usage = "usage_convertRefStorageFormat")
 	private String format = "reftable"; //$NON-NLS-1$
 
+	@Option(name = "--backup", handler = ExplicitBooleanOptionHandler.class, aliases = {
+			"-b" }, usage = "usage_convertRefStorageBackup")
+	private boolean backup = true;
+
 	/** {@inheritDoc} */
 	@Override
 	protected void run() throws Exception {
-		((FileRepository) db).convertRefStorage(format, true, true);
+		((FileRepository) db).convertRefStorage(format, true, backup);
 	}
 }