DfsGarbageCollectorTest: add test for bitmap index creation

Change-Id: Ibb9b2f8fc0f5180728904f243bf372f8a233383d

1 files changed, 67 insertions, 1 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 05360dc052..1bff27e26a 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
@@ -18,10 +18,11 @@ 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;
+import org.eclipse.jgit.internal.storage.file.PackBitmapIndex;
+import org.eclipse.jgit.internal.storage.pack.PackExt;
 import org.eclipse.jgit.internal.storage.reftable.RefCursor;
 import org.eclipse.jgit.internal.storage.reftable.ReftableConfig;
 import org.eclipse.jgit.internal.storage.reftable.ReftableReader;
@@ -1178,6 +1179,71 @@ public class DfsGarbageCollectorTest {
 		assertFalse(gcRestPack.hasObjectSizeIndex(reader));
 	}
 
+	@Test
+	public void bitmapIndexWrittenDuringGc() throws Exception {
+		int numBranches = 2;
+		int commitsPerBranch = 50;
+
+		RevCommit commit0 = commit().message("0").create();
+		git.update("branch0", commit0);
+		RevCommit branch1 = commitChain(commit0, commitsPerBranch);
+		git.update("branch1", branch1);
+		RevCommit branch2 = commitChain(commit0, commitsPerBranch);
+		git.update("branch2", branch2);
+
+		int contiguousCommitCount = 5;
+		int recentCommitSpan = 2;
+		int recentCommitCount = 10;
+		int distantCommitSpan = 5;
+
+		PackConfig packConfig = new PackConfig();
+		packConfig.setBitmapContiguousCommitCount(contiguousCommitCount);
+		packConfig.setBitmapRecentCommitSpan(recentCommitSpan);
+		packConfig.setBitmapRecentCommitCount(recentCommitCount);
+		packConfig.setBitmapDistantCommitSpan(distantCommitSpan);
+
+		DfsGarbageCollector gc = new DfsGarbageCollector(repo);
+		gc.setPackConfig(packConfig);
+		run(gc);
+
+		DfsPackFile pack = odb.getPacks()[0];
+		PackBitmapIndex bitmapIndex = pack.getBitmapIndex(odb.newReader());
+		assertTrue("pack file has bitmap index extension",
+				pack.getPackDescription().hasFileExt(PackExt.BITMAP_INDEX));
+
+		int recentCommitsPerBranch = (recentCommitCount - contiguousCommitCount
+				- 1) / recentCommitSpan;
+		assertEquals("expected recent commits", 2, recentCommitsPerBranch);
+
+		int distantCommitsPerBranch = (commitsPerBranch - 1 - recentCommitCount)
+				/ distantCommitSpan;
+		assertEquals("expected distant commits", 7, distantCommitsPerBranch);
+
+		int branchBitmapsCount = contiguousCommitCount
+				+ numBranches
+						* (recentCommitsPerBranch
+						+ distantCommitsPerBranch);
+		assertEquals("expected bitmaps count", 23, branchBitmapsCount);
+		assertEquals("bitmap index has expected number of bitmaps",
+				branchBitmapsCount,
+				bitmapIndex.getBitmapCount());
+
+		// The count is just a function of whether any bitmaps happen to
+		// compress efficiently against the others in the index. We expect for
+		// this test that this there will be at least one like this, but the
+		// actual count is situation-specific
+		assertTrue("bitmap index has xor-compressed bitmaps",
+				bitmapIndex.getXorBitmapCount() > 0);
+	}
+
+	private RevCommit commitChain(RevCommit parent, int length)
+			throws Exception {
+		for (int i = 0; i < length; i++) {
+			parent = commit().message("" + i).parent(parent).create();
+		}
+		return parent;
+	}
+
 	private static DfsPackFile findFirstBySource(DfsPackFile[] packs, PackSource source) {
 		return Arrays.stream(packs)
 				.filter(p -> p.getPackDescription().getPackSource() == source)