Adds a callAsMap() function to LsRemoteCommand.

The call() function of LsRemoteCommand returns Collection<Ref>, while its
internal is using Map<String, Ref> all the time. Sometimes the map is much more
useful to the caller so add a callAsMap() function to keep the API
compatibility.

Change-Id: Icb96b71277d5e2de59872aa777352dedc048c4e3
Signed-off-by: Yuxuan 'fishy' Wang <fishywang@google.com>

org.eclipse.jgit/src/org/eclipse/jgit/api/LsRemoteCommand.java

@@ -46,6 +46,7 @@ import java.net.URISyntaxException;
 import java.text.MessageFormat;
 import java.util.ArrayList;
 import java.util.Collection;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.Map;
 
@@ -153,6 +154,28 @@ public class LsRemoteCommand extends
 	public Collection<Ref> call() throws GitAPIException,
 			InvalidRemoteException,
 			org.eclipse.jgit.api.errors.TransportException {
+		return execute().values();
+	}
+
+	/**
+	 * Same as {@link #call()}, but return Map instead of Collection.
+	 *
+	 * @return a map from names to references in the remote repository
+	 * @throws InvalidRemoteException
+	 *             when called with an invalid remote uri
+	 * @throws org.eclipse.jgit.api.errors.TransportException
+	 *             for errors that occurs during transport
+	 * @since 3.5
+	 */
+	public Map<String, Ref> callAsMap() throws GitAPIException,
+			InvalidRemoteException,
+			org.eclipse.jgit.api.errors.TransportException {
+		return Collections.unmodifiableMap(execute());
+	}
+
+	protected Map<String, Ref> execute() throws GitAPIException,
+			InvalidRemoteException,
+			org.eclipse.jgit.api.errors.TransportException {
 		checkCallable();
 
 		Transport transport = null;
@@ -184,7 +207,7 @@ public class LsRemoteCommand extends
 							refmap.put(r.getName(), r);
 							break;
 						}
-			return refmap.values();
+			return refmap;
 		} catch (URISyntaxException e) {
 			throw new InvalidRemoteException(MessageFormat.format(
 					JGitText.get().invalidRemote, remote));

org.eclipse.jgit/src/org/eclipse/jgit/gitrepo/RepoCommand.java

@@ -160,16 +160,10 @@ public class RepoCommand extends GitCommand<RevCommit> {
 	/** A default implementation of {@link RemoteReader} callback. */
 	public static class DefaultRemoteReader implements RemoteReader {
 		public ObjectId sha1(String uri, String ref) throws GitAPIException {
-			Collection<Ref> refs = Git
+			Map<String, Ref> map = Git
 					.lsRemoteRepository()
 					.setRemote(uri)
-					.call();
-			// Since LsRemoteCommand.call() only returned Map.values() to us, we
-			// have to rebuild the map here.
-			Map<String, Ref> map = new HashMap<String, Ref>(refs.size());
-			for (Ref r : refs)
-				map.put(r.getName(), r);
-
+					.callAsMap();
 			Ref r = RefDatabase.findRef(map, ref);
 			return r != null ? r.getObjectId() : null;
 		}