DfsPackFile: Enable/disable object size index via DfsReaderOptions

DfsPackFile always uses the object size index if available. That is
the desired final state, but for a safe rollout, we should be able to
disable using the object size index.

Add an option (dfs.useObjectSizeIndex) to enable/disable the usage of
the object size index. False by default.

This changes the default from true to false. It only makes a different
for the DFS stack when writing of the index was explicitely
enabled. This is an optimization, so it shouldn't cause any
regression. Operators can restore previous behaviour setting
"dfs.useObjectSizeIndex" to true.

Change-Id: I44bf5a57e3942a4ecfe66d58bfa9175e99f96fcc

5 files changed, 8 insertions, 0 deletions

diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/dfs/DfsGarbageCollectorTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/dfs/DfsGarbageCollectorTest.java
index e193de9764..2be11d32ea 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/dfs/DfsGarbageCollectorTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/dfs/DfsGarbageCollectorTest.java
@@ -18,6 +18,7 @@ import java.io.IOException;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.concurrent.TimeUnit;
+
 import org.eclipse.jgit.internal.storage.commitgraph.CommitGraph;
 import org.eclipse.jgit.internal.storage.commitgraph.CommitGraphWriter;
 import org.eclipse.jgit.internal.storage.dfs.DfsObjDatabase.PackSource;
@@ -1171,6 +1172,7 @@ public class DfsGarbageCollectorTest {
 
 		gcWithObjectSizeIndex(10);
 
+		odb.getReaderOptions().setUseObjectSizeIndex(true);
 		DfsReader reader = odb.newReader();
 		DfsPackFile gcPack = findFirstBySource(odb.getPacks(), GC);
 		assertTrue(gcPack.hasObjectSizeIndex(reader));
@@ -1191,6 +1193,7 @@ public class DfsGarbageCollectorTest {
 
 		gcWithObjectSizeIndex(10);
 
+		odb.getReaderOptions().setUseObjectSizeIndex(true);
 		DfsReader reader = odb.newReader();
 		DfsPackFile gcPack = findFirstBySource(odb.getPacks(), GC);
 		assertTrue(gcPack.hasObjectSizeIndex(reader));
diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/dfs/DfsInserterTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/dfs/DfsInserterTest.java
index b84a0b00ae..0b558edf2c 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/dfs/DfsInserterTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/dfs/DfsInserterTest.java
@@ -295,6 +295,7 @@ public class DfsInserterTest {
 	public void testObjectSizeIndexOnInsert() throws IOException {
 		db.getConfig().setInt(CONFIG_PACK_SECTION, null,
 				CONFIG_KEY_MIN_BYTES_OBJ_SIZE_INDEX, 0);
+		db.getObjectDatabase().getReaderOptions().setUseObjectSizeIndex(true);
 
 		byte[] contents = Constants.encode("foo");
 		ObjectId fooId;
diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/dfs/DfsPackFileTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/dfs/DfsPackFileTest.java
index d21e51f276..bc851f8dde 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/dfs/DfsPackFileTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/dfs/DfsPackFileTest.java
@@ -126,6 +126,7 @@ public class DfsPackFileTest {
 		setObjectSizeIndexMinBytes(0);
 		ObjectId blobId = setupPack(512, 800);
 
+		db.getObjectDatabase().getReaderOptions().setUseObjectSizeIndex(true);
 		DfsReader reader = db.getObjectDatabase().newReader();
 		DfsPackFile pack = db.getObjectDatabase().getPacks()[0];
 		assertTrue(pack.hasObjectSizeIndex(reader));
diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/dfs/DfsPackParserTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/dfs/DfsPackParserTest.java
index 130af27773..c1cd231c66 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/dfs/DfsPackParserTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/dfs/DfsPackParserTest.java
@@ -61,6 +61,7 @@ public class DfsPackParserTest {
 			ins.flush();
 		}
 
+		repo.getObjectDatabase().getReaderOptions().setUseObjectSizeIndex(true);
 		DfsReader reader = repo.getObjectDatabase().newReader();
 		PackList packList = repo.getObjectDatabase().getPackList();
 		assertEquals(1, packList.packs.length);
diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/dfs/DfsReaderTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/dfs/DfsReaderTest.java
index 254184ee80..a0c228906e 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/dfs/DfsReaderTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/dfs/DfsReaderTest.java
@@ -37,6 +37,8 @@ public class DfsReaderTest {
 	@Before
 	public void setUp() {
 		db = new InMemoryRepository(new DfsRepositoryDescription("test"));
+		// These tests assume the object size index is enabled.
+		db.getObjectDatabase().getReaderOptions().setUseObjectSizeIndex(true);
 	}
 
 	@Test