refactor(repository): refactored v1 encryption overhead to be a funct…

…ion that's only invoked when actual V1 index is opened (#2300)

repo/content/committed_content_index.go

@@ -38,7 +38,7 @@ type committedContentIndex struct {
 	// +checklocks:mu
 	merged index.Merged
 
-	v1PerContentOverhead uint32
+	v1PerContentOverhead func() int
 	formatProvider       format.Provider
 
 	// fetchOne loads one index blob
@@ -354,7 +354,7 @@ func (c *committedContentIndex) missingIndexBlobs(ctx context.Context, blobs []b
 }
 
 func newCommittedContentIndex(caching *CachingOptions,
-	v1PerContentOverhead uint32,
+	v1PerContentOverhead func() int,
 	formatProvider format.Provider,
 	fetchOne func(ctx context.Context, blobID blob.ID, output *gather.WriteBuffer) error,
 	log logging.Logger,

repo/content/committed_content_index_cache_test.go

@@ -20,15 +20,15 @@ func TestCommittedContentIndexCache_Disk(t *testing.T) {
 
 	ta := faketime.NewClockTimeWithOffset(0)
 
-	testCache(t, &diskCommittedContentIndexCache{testutil.TempDirectory(t), ta.NowFunc(), 3, testlogging.Printf(t.Logf, ""), DefaultIndexCacheSweepAge}, ta)
+	testCache(t, &diskCommittedContentIndexCache{testutil.TempDirectory(t), ta.NowFunc(), func() int { return 3 }, testlogging.Printf(t.Logf, ""), DefaultIndexCacheSweepAge}, ta)
 }
 
 func TestCommittedContentIndexCache_Memory(t *testing.T) {
 	t.Parallel()
 
 	testCache(t, &memoryCommittedContentIndexCache{
 		contents:             map[blob.ID]index.Index{},
-		v1PerContentOverhead: 3,
+		v1PerContentOverhead: func() int { return 3 },
 	}, nil)
 }
 

repo/content/committed_content_index_disk_cache.go

@@ -24,7 +24,7 @@ const (
 type diskCommittedContentIndexCache struct {
 	dirname              string
 	timeNow              func() time.Time
-	v1PerContentOverhead uint32
+	v1PerContentOverhead func() int
 	log                  logging.Logger
 	minSweepAge          time.Duration
 }

repo/content/committed_content_index_mem_cache.go

@@ -17,7 +17,7 @@ type memoryCommittedContentIndexCache struct {
 	// +checklocks:mu
 	contents map[blob.ID]index.Index
 
-	v1PerContentOverhead uint32 // +checklocksignore
+	v1PerContentOverhead func() int // +checklocksignore
 }
 
 func (m *memoryCommittedContentIndexCache) hasIndexBlobID(ctx context.Context, indexBlobID blob.ID) (bool, error) {

repo/content/committed_read_manager.go

@@ -472,7 +472,7 @@ func (sm *SharedManager) setupReadManagerCaches(ctx context.Context, caching *Ca
 	sm.metadataCache = metadataCache
 	sm.indexBlobCache = indexBlobCache
 	sm.committedContents = newCommittedContentIndex(caching,
-		uint32(sm.format.Encryptor().Overhead()),
+		sm.format.Encryptor().Overhead,
 		sm.format,
 		sm.enc.getEncryptedBlob,
 		sm.namedLogger("committed-content-index"),

repo/content/content_index_recovery.go

@@ -22,7 +22,7 @@ func (bm *WriteManager) RecoverIndexFromPackBlob(ctx context.Context, packFile b
 		return nil, err
 	}
 
-	ndx, err := index.Open(localIndexBytes.Bytes().ToByteSlice(), nil, uint32(bm.format.Encryptor().Overhead()))
+	ndx, err := index.Open(localIndexBytes.Bytes().ToByteSlice(), nil, bm.format.Encryptor().Overhead)
 	if err != nil {
 		return nil, errors.Errorf("unable to open index in file %v", packFile)
 	}

repo/content/content_manager_indexes.go

@@ -88,7 +88,7 @@ func ParseIndexBlob(ctx context.Context, blobID blob.ID, encrypted gather.Bytes,
 		return nil, errors.Wrap(err, "unable to decrypt index blob")
 	}
 
-	ndx, err := index.Open(data.Bytes().ToByteSlice(), nil, uint32(crypter.Encryptor().Overhead()))
+	ndx, err := index.Open(data.Bytes().ToByteSlice(), nil, crypter.Encryptor().Overhead)
 	if err != nil {
 		return nil, errors.Wrapf(err, "unable to open index blob")
 	}

repo/content/index/index.go

@@ -25,15 +25,15 @@ type Index interface {
 }
 
 // Open reads an Index from a given reader. The caller must call Close() when the index is no longer used.
-func Open(data []byte, closer func() error, v1PerContentOverhead uint32) (Index, error) {
+func Open(data []byte, closer func() error, v1PerContentOverhead func() int) (Index, error) {
 	h, err := v1ReadHeader(data)
 	if err != nil {
 		return nil, errors.Wrap(err, "invalid header")
 	}
 
 	switch h.version {
 	case Version1:
-		return openV1PackIndex(h, data, closer, v1PerContentOverhead)
+		return openV1PackIndex(h, data, closer, uint32(v1PerContentOverhead()))
 
 	case Version2:
 		return openV2PackIndex(data, closer)

repo/content/index/merged_test.go

@@ -249,5 +249,5 @@ func indexWithItems(items ...Info) (Index, error) {
 		return nil, errors.Wrap(err, "build error")
 	}
 
-	return Open(buf.Bytes(), nil, fakeEncryptionOverhead)
+	return Open(buf.Bytes(), nil, func() int { return fakeEncryptionOverhead })
 }

repo/content/index/packindex_test.go

@@ -188,7 +188,7 @@ func testPackIndex(t *testing.T, version int) {
 		fuzzTestIndexOpen(data1)
 	})
 
-	ndx, err := Open(data1, nil, fakeEncryptionOverhead)
+	ndx, err := Open(data1, nil, func() int { return fakeEncryptionOverhead })
 	if err != nil {
 		t.Fatalf("can't open index: %v", err)
 	}
@@ -281,7 +281,7 @@ func TestPackIndexPerContentLimits(t *testing.T) {
 		if tc.errMsg == "" {
 			require.NoError(t, b.buildV2(&result))
 
-			pi, err := Open(result.Bytes(), nil, fakeEncryptionOverhead)
+			pi, err := Open(result.Bytes(), nil, func() int { return fakeEncryptionOverhead })
 			require.NoError(t, err)
 
 			got, err := pi.GetInfo(cid)
@@ -399,7 +399,7 @@ func fuzzTestIndexOpen(originalData []byte) {
 	rnd := rand.New(rand.NewSource(12345))
 
 	fuzzTest(rnd, originalData, 50000, func(d []byte) {
-		ndx, err := Open(d, nil, 0)
+		ndx, err := Open(d, nil, func() int { return 0 })
 		if err != nil {
 			return
 		}

repo/content/index_blob_manager_v0.go

@@ -554,7 +554,7 @@ func addIndexBlobsToBuilder(ctx context.Context, enc *encryptedBlobMgr, bld inde
 		return errors.Wrapf(err, "error getting index %q", indexBlobID)
 	}
 
-	ndx, err := index.Open(data.ToByteSlice(), nil, uint32(enc.crypter.Encryptor().Overhead()))
+	ndx, err := index.Open(data.ToByteSlice(), nil, enc.crypter.Encryptor().Overhead)
 	if err != nil {
 		return errors.Wrapf(err, "unable to open index blob %q", indexBlobID)
 	}

repo/ecc/ecc.go

@@ -95,5 +95,5 @@ func (e encryptorWrapper) Decrypt(cipherText gather.Bytes, contentID []byte, out
 }
 
 func (e encryptorWrapper) Overhead() int {
-	return e.impl.Overhead() + e.next.Overhead()
+	panic("Overhead() should not be called")
 }