Add RefDatabase#getReflogReader methods

to fix broken abstraction in FileRepository#getReflogReader(String).
How to get a ReflogReader depends on the chosen RefDatabase
implementation, hence the #getReflogReader methods should be there.

This also fixes a bug in FileRepository#getReflogReader(Ref) which
didn't work if FileReftableDatabase was used as RefDatabase since it
always returned the implementation only suitable for RefDirectory.

Change-Id: I0859990f9390ab96596b6c344966c687dfbbf167

Author: msohn

Diff for: org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/RefDatabaseConflictingNamesTest.java

@@ -70,6 +70,11 @@ public List<Ref> getAdditionalRefs() throws IOException {
 			return null;
 		}
 
+		@Override
+		public ReflogReader getReflogReader(Ref ref) throws IOException {
+			return null;
+		}
+
 		@Override
 		public void create() throws IOException {
 			// Not needed

Diff for: org.eclipse.jgit/.settings/.api_filters

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<component id="org.eclipse.jgit" version="2">
+    <resource path="src/org/eclipse/jgit/lib/RefDatabase.java" type="org.eclipse.jgit.lib.RefDatabase">
+        <filter id="336695337">
+            <message_arguments>
+                <message_argument value="org.eclipse.jgit.lib.RefDatabase"/>
+                <message_argument value="getReflogReader(Ref)"/>
+            </message_arguments>
+        </filter>
+        <filter id="336695337">
+            <message_arguments>
+                <message_argument value="org.eclipse.jgit.lib.RefDatabase"/>
+                <message_argument value="getReflogReader(String)"/>
+            </message_arguments>
+        </filter>
+    </resource>
+</component>

Diff for: org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/dfs/DfsReftableDatabase.java

@@ -28,6 +28,7 @@
 import org.eclipse.jgit.lib.NullProgressMonitor;
 import org.eclipse.jgit.lib.ObjectId;
 import org.eclipse.jgit.lib.Ref;
+import org.eclipse.jgit.lib.ReflogReader;
 import org.eclipse.jgit.revwalk.RevWalk;
 import org.eclipse.jgit.transport.ReceiveCommand;
 import org.eclipse.jgit.util.RefList;
@@ -176,6 +177,11 @@ public List<Ref> getRefsByPrefixWithExclusions(String include, Set<String> exclu
 		return reftableDatabase.getRefsByPrefixWithExclusions(include, excludes);
 	}
 
+	@Override
+	public ReflogReader getReflogReader(Ref ref) throws IOException {
+		return reftableDatabase.getReflogReader(ref.getName());
+	}
+
 	@Override
 	public Set<Ref> getTipsWithSha1(ObjectId id) throws IOException {
 		if (!getReftableConfig().isIndexObjects()) {

Diff for: org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/FileReftableDatabase.java

@@ -90,7 +90,13 @@ public MergedReftable openMergedReftable() throws IOException {
 		};
 	}
 
-	ReflogReader getReflogReader(String refname) throws IOException {
+	@Override
+	public ReflogReader getReflogReader(Ref ref) throws IOException {
+		return reftableDatabase.getReflogReader(ref.getName());
+	}
+
+	@Override
+	public ReflogReader getReflogReader(String refname) throws IOException {
 		return reftableDatabase.getReflogReader(refname);
 	}
 

Diff for: org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/FileRepository.java

@@ -31,7 +31,6 @@
 import java.util.Objects;
 import java.util.Set;
 
-import org.eclipse.jgit.annotations.NonNull;
 import org.eclipse.jgit.annotations.Nullable;
 import org.eclipse.jgit.api.errors.GitAPIException;
 import org.eclipse.jgit.api.errors.JGitInternalException;
@@ -542,29 +541,6 @@ public void notifyIndexChanged(boolean internal) {
 		fireEvent(new IndexChangedEvent(internal));
 	}
 
-	@Override
-	public ReflogReader getReflogReader(String refName) throws IOException {
-		if (refs instanceof FileReftableDatabase) {
-			// Cannot use findRef: reftable stores log data for deleted or renamed
-			// branches.
-			return ((FileReftableDatabase)refs).getReflogReader(refName);
-		}
-
-		// TODO: use exactRef here, which offers more predictable and therefore preferable
-		// behavior.
-		Ref ref = findRef(refName);
-		if (ref == null) {
-			return null;
-		}
-		return new ReflogReaderImpl(this, ref.getName());
-	}
-
-	@Override
-	public @NonNull ReflogReader getReflogReader(@NonNull Ref ref)
-			throws IOException {
-		return new ReflogReaderImpl(this, ref.getName());
-	}
-
 	@Override
 	public AttributesNodeProvider createAttributesNodeProvider() {
 		return new AttributesNodeProviderImpl(this);
@@ -697,8 +673,8 @@ void convertToPackedRefs(boolean writeLogs, boolean backup) throws IOException {
 			}
 
 			if (writeLogs) {
-				List<ReflogEntry> logs = oldDb.getReflogReader(r.getName())
-						.getReverseEntries();
+				ReflogReader reflogReader = oldDb.getReflogReader(r);
+				List<ReflogEntry> logs = reflogReader.getReverseEntries();
 				Collections.reverse(logs);
 				for (ReflogEntry e : logs) {
 					logWriter.log(r.getName(), e);

Diff for: org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/RefDirectory.java

@@ -76,6 +76,7 @@
 import org.eclipse.jgit.lib.RefDatabase;
 import org.eclipse.jgit.lib.RefUpdate;
 import org.eclipse.jgit.lib.RefWriter;
+import org.eclipse.jgit.lib.ReflogReader;
 import org.eclipse.jgit.lib.Repository;
 import org.eclipse.jgit.lib.SymbolicRef;
 import org.eclipse.jgit.revwalk.RevObject;
@@ -456,6 +457,11 @@ public List<Ref> getAdditionalRefs() throws IOException {
 		return ret;
 	}
 
+	@Override
+	public ReflogReader getReflogReader(Ref ref) throws IOException {
+		return new ReflogReaderImpl(getRepository(), ref.getName());
+	}
+
 	@SuppressWarnings("unchecked")
 	private RefList<Ref> upcast(RefList<? extends Ref> loose) {
 		return (RefList<Ref>) loose;

Diff for: org.eclipse.jgit/src/org/eclipse/jgit/lib/RefDatabase.java

@@ -355,6 +355,42 @@ public List<Ref> getRefs() throws IOException {
 		return getRefsByPrefix(ALL);
 	}
 
+	/**
+	 * Get the reflog reader
+	 *
+	 * @param refName
+	 *            a {@link java.lang.String} object.
+	 * @return a {@link org.eclipse.jgit.lib.ReflogReader} for the supplied
+	 *         refname, or {@code null} if the named ref does not exist.
+	 * @throws java.io.IOException
+	 *             the ref could not be accessed.
+	 * @since 7.2
+	 */
+	@Nullable
+	public ReflogReader getReflogReader(String refName) throws IOException {
+		// TODO: use exactRef here, which offers more predictable and therefore
+		// preferable behavior.
+		Ref ref = findRef(refName);
+		if (ref == null) {
+			return null;
+		}
+		return getReflogReader(ref);
+	}
+
+	/**
+	 * Get the reflog reader.
+	 *
+	 * @param ref
+	 *            a Ref
+	 * @return a {@link org.eclipse.jgit.lib.ReflogReader} for the supplied ref.
+	 * @throws IOException
+	 *             if an IO error occurred
+	 * @since 7.2
+	 */
+	@NonNull
+	public abstract ReflogReader getReflogReader(@NonNull Ref ref)
+			throws IOException;
+
 	/**
 	 * Get a section of the reference namespace.
 	 *

Diff for: org.eclipse.jgit/src/org/eclipse/jgit/lib/Repository.java

@@ -1694,24 +1694,25 @@ public void setGitwebDescription(@Nullable String description)
 	 * @since 3.0
 	 */
 	@Nullable
-	public abstract ReflogReader getReflogReader(String refName)
-			throws IOException;
+	public ReflogReader getReflogReader(String refName) throws IOException {
+		return getRefDatabase().getReflogReader(refName);
+	}
 
 	/**
 	 * Get the reflog reader. Subclasses should override this method and provide
 	 * a more efficient implementation.
 	 *
 	 * @param ref
 	 *            a Ref
-	 * @return a {@link org.eclipse.jgit.lib.ReflogReader} for the supplied ref,
-	 *         or {@code null} if the ref does not exist.
+	 * @return a {@link org.eclipse.jgit.lib.ReflogReader} for the supplied ref.
 	 * @throws IOException
 	 *             if an IO error occurred
 	 * @since 5.13.2
 	 */
-	public @Nullable ReflogReader getReflogReader(@NonNull	Ref ref)
+	@NonNull
+	public ReflogReader getReflogReader(@NonNull Ref ref)
 			throws IOException {
-		return getReflogReader(ref.getName());
+		return getRefDatabase().getReflogReader(ref);
 	}
 
 	/**