Merge pull request #2640 from greatroar/simplify-loadblob-usage

Simplify Repository.LoadBlob usage
This commit is contained in:
MichaelEischer 2020-04-23 20:23:35 +02:00 committed by GitHub
commit d4bd32a37e
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9 changed files with 48 additions and 124 deletions

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@ -170,18 +170,15 @@ func runCat(gopts GlobalOptions, args []string) error {
case "blob":
for _, t := range []restic.BlobType{restic.DataBlob, restic.TreeBlob} {
list, found := repo.Index().Lookup(id, t)
_, found := repo.Index().Lookup(id, t)
if !found {
continue
}
blob := list[0]
buf := make([]byte, blob.Length)
n, err := repo.LoadBlob(gopts.ctx, t, id, buf)
buf, err := repo.LoadBlob(gopts.ctx, t, id, nil)
if err != nil {
return err
}
buf = buf[:n]
_, err = os.Stdout.Write(buf)
return err

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@ -171,24 +171,15 @@ func runDump(opts DumpOptions, gopts GlobalOptions, args []string) error {
}
func getNodeData(ctx context.Context, output io.Writer, repo restic.Repository, node *restic.Node) error {
var buf []byte
var (
buf []byte
err error
)
for _, id := range node.Content {
size, found := repo.LookupBlobSize(id, restic.DataBlob)
if !found {
return errors.Errorf("id %v not found in repository", id)
}
buf = buf[:cap(buf)]
if len(buf) < restic.CiphertextLength(int(size)) {
buf = restic.NewBlobBuffer(int(size))
}
n, err := repo.LoadBlob(ctx, restic.DataBlob, id, buf)
buf, err = repo.LoadBlob(ctx, restic.DataBlob, id, buf)
if err != nil {
return err
}
buf = buf[:n]
_, err = output.Write(buf)
if err != nil {

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@ -228,13 +228,13 @@ func TestEnsureFileContent(ctx context.Context, t testing.TB, repo restic.Reposi
content := make([]byte, restic.CiphertextLength(len(file.Content)))
pos := 0
for _, id := range node.Content {
n, err := repo.LoadBlob(ctx, restic.DataBlob, id, content[pos:])
part, err := repo.LoadBlob(ctx, restic.DataBlob, id, content[pos:])
if err != nil {
t.Fatalf("error loading blob %v: %v", id.Str(), err)
return
}
pos += n
pos += len(part)
}
content = content[:pos]

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@ -96,15 +96,14 @@ func (f *file) getBlobAt(ctx context.Context, i int) (blob []byte, err error) {
f.blobs[j] = nil
}
buf := restic.NewBlobBuffer(f.sizes[i])
n, err := f.root.repo.LoadBlob(ctx, restic.DataBlob, f.node.Content[i], buf)
blob, err = f.root.repo.LoadBlob(ctx, restic.DataBlob, f.node.Content[i], nil)
if err != nil {
debug.Log("LoadBlob(%v, %v) failed: %v", f.node.Name, f.node.Content[i], err)
return nil, err
}
f.blobs[i] = buf[:n]
f.blobs[i] = blob
return buf[:n], nil
return blob, nil
}
func (f *file) Read(ctx context.Context, req *fuse.ReadRequest, resp *fuse.ReadResponse) error {

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@ -94,12 +94,11 @@ func TestFuseFile(t *testing.T) {
rtest.Assert(t, found, "Expected to find blob id %v", id)
filesize += uint64(size)
buf := restic.NewBlobBuffer(int(size))
n, err := repo.LoadBlob(context.TODO(), restic.DataBlob, id, buf)
buf, err := repo.LoadBlob(context.TODO(), restic.DataBlob, id, nil)
rtest.OK(t, err)
if uint(n) != size {
t.Fatalf("not enough bytes read for id %v: want %v, got %v", id.Str(), size, n)
if len(buf) != int(size) {
t.Fatalf("not enough bytes read for id %v: want %v, got %v", id.Str(), size, len(buf))
}
if uint(len(buf)) != size {

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@ -130,17 +130,16 @@ func (r *Repository) sortCachedPacks(blobs []restic.PackedBlob) []restic.PackedB
return append(cached, noncached...)
}
// loadBlob tries to load and decrypt content identified by t and id from a
// pack from the backend, the result is stored in plaintextBuf, which must be
// large enough to hold the complete blob.
func (r *Repository) loadBlob(ctx context.Context, id restic.ID, t restic.BlobType, plaintextBuf []byte) (int, error) {
debug.Log("load %v with id %v (buf len %v, cap %d)", t, id, len(plaintextBuf), cap(plaintextBuf))
// LoadBlob loads a blob of type t from the repository.
// It may use all of buf[:cap(buf)] as scratch space.
func (r *Repository) LoadBlob(ctx context.Context, t restic.BlobType, id restic.ID, buf []byte) ([]byte, error) {
debug.Log("load %v with id %v (buf len %v, cap %d)", t, id, len(buf), cap(buf))
// lookup packs
blobs, found := r.idx.Lookup(id, t)
if !found {
debug.Log("id %v not found in index", id)
return 0, errors.Errorf("id %v not found in repository", id)
return nil, errors.Errorf("id %v not found in repository", id)
}
// try cached pack files first
@ -157,13 +156,14 @@ func (r *Repository) loadBlob(ctx context.Context, id restic.ID, t restic.BlobTy
// load blob from pack
h := restic.Handle{Type: restic.DataFile, Name: blob.PackID.String()}
if uint(cap(plaintextBuf)) < blob.Length {
return 0, errors.Errorf("buffer is too small: %v < %v", cap(plaintextBuf), blob.Length)
switch {
case cap(buf) < int(blob.Length):
buf = make([]byte, blob.Length)
case len(buf) != int(blob.Length):
buf = buf[:blob.Length]
}
plaintextBuf = plaintextBuf[:blob.Length]
n, err := restic.ReadAt(ctx, r.be, h, int64(blob.Offset), plaintextBuf)
n, err := restic.ReadAt(ctx, r.be, h, int64(blob.Offset), buf)
if err != nil {
debug.Log("error loading blob %v: %v", blob, err)
lastError = err
@ -178,7 +178,7 @@ func (r *Repository) loadBlob(ctx context.Context, id restic.ID, t restic.BlobTy
}
// decrypt
nonce, ciphertext := plaintextBuf[:r.key.NonceSize()], plaintextBuf[r.key.NonceSize():]
nonce, ciphertext := buf[:r.key.NonceSize()], buf[r.key.NonceSize():]
plaintext, err := r.key.Open(ciphertext[:0], nonce, ciphertext, nil)
if err != nil {
lastError = errors.Errorf("decrypting blob %v failed: %v", id, err)
@ -191,16 +191,16 @@ func (r *Repository) loadBlob(ctx context.Context, id restic.ID, t restic.BlobTy
continue
}
// move decrypted data to the start of the provided buffer
copy(plaintextBuf[0:], plaintext)
return len(plaintext), nil
// move decrypted data to the start of the buffer
copy(buf, plaintext)
return buf[:len(plaintext)], nil
}
if lastError != nil {
return 0, lastError
return nil, lastError
}
return 0, errors.Errorf("loading blob %v from %v packs failed", id.Str(), len(blobs))
return nil, errors.Errorf("loading blob %v from %v packs failed", id.Str(), len(blobs))
}
// LoadJSONUnpacked decrypts the data and afterwards calls json.Unmarshal on
@ -670,31 +670,6 @@ func (r *Repository) Close() error {
return r.be.Close()
}
// LoadBlob loads a blob of type t from the repository to the buffer. buf must
// be large enough to hold the encrypted blob, since it is used as scratch
// space.
func (r *Repository) LoadBlob(ctx context.Context, t restic.BlobType, id restic.ID, buf []byte) (int, error) {
debug.Log("load blob %v into buf (len %v, cap %v)", id, len(buf), cap(buf))
size, found := r.idx.LookupSize(id, t)
if !found {
return 0, errors.Errorf("id %v not found in repository", id)
}
if cap(buf) < restic.CiphertextLength(int(size)) {
return 0, errors.Errorf("buffer is too small for data blob (%d < %d)", cap(buf), restic.CiphertextLength(int(size)))
}
n, err := r.loadBlob(ctx, id, t, buf)
if err != nil {
return 0, err
}
buf = buf[:n]
debug.Log("loaded %d bytes into buf %p", len(buf), buf)
return len(buf), err
}
// SaveBlob saves a blob of type t into the repository. If id is the null id, it
// will be computed and returned.
func (r *Repository) SaveBlob(ctx context.Context, t restic.BlobType, buf []byte, id restic.ID) (restic.ID, error) {
@ -709,19 +684,10 @@ func (r *Repository) SaveBlob(ctx context.Context, t restic.BlobType, buf []byte
func (r *Repository) LoadTree(ctx context.Context, id restic.ID) (*restic.Tree, error) {
debug.Log("load tree %v", id)
size, found := r.idx.LookupSize(id, restic.TreeBlob)
if !found {
return nil, errors.Errorf("tree %v not found in repository", id)
}
debug.Log("size is %d, create buffer", size)
buf := restic.NewBlobBuffer(int(size))
n, err := r.loadBlob(ctx, id, restic.TreeBlob, buf)
buf, err := r.LoadBlob(ctx, restic.TreeBlob, id, nil)
if err != nil {
return nil, err
}
buf = buf[:n]
t := &restic.Tree{}
err = json.Unmarshal(buf, t)

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@ -43,10 +43,9 @@ func TestSave(t *testing.T) {
// rtest.OK(t, repo.SaveIndex())
// read back
buf := restic.NewBlobBuffer(size)
n, err := repo.LoadBlob(context.TODO(), restic.DataBlob, id, buf)
buf, err := repo.LoadBlob(context.TODO(), restic.DataBlob, id, nil)
rtest.OK(t, err)
rtest.Equals(t, len(buf), n)
rtest.Equals(t, size, len(buf))
rtest.Assert(t, len(buf) == len(data),
"number of bytes read back does not match: expected %d, got %d",
@ -77,10 +76,9 @@ func TestSaveFrom(t *testing.T) {
rtest.OK(t, repo.Flush(context.Background()))
// read back
buf := restic.NewBlobBuffer(size)
n, err := repo.LoadBlob(context.TODO(), restic.DataBlob, id, buf)
buf, err := repo.LoadBlob(context.TODO(), restic.DataBlob, id, nil)
rtest.OK(t, err)
rtest.Equals(t, len(buf), n)
rtest.Equals(t, size, len(buf))
rtest.Assert(t, len(buf) == len(data),
"number of bytes read back does not match: expected %d, got %d",
@ -164,33 +162,17 @@ func TestLoadBlob(t *testing.T) {
rtest.OK(t, err)
rtest.OK(t, repo.Flush(context.Background()))
// first, test with buffers that are too small
for _, testlength := range []int{length - 20, length, restic.CiphertextLength(length) - 1} {
buf = make([]byte, 0, testlength)
n, err := repo.LoadBlob(context.TODO(), restic.DataBlob, id, buf)
if err == nil {
t.Errorf("LoadBlob() did not return an error for a buffer that is too small to hold the blob")
continue
}
if n != 0 {
t.Errorf("LoadBlob() returned an error and n > 0")
continue
}
}
// then use buffers that are large enough
base := restic.CiphertextLength(length)
for _, testlength := range []int{base, base + 7, base + 15, base + 1000} {
for _, testlength := range []int{0, base - 20, base - 1, base, base + 7, base + 15, base + 1000} {
buf = make([]byte, 0, testlength)
n, err := repo.LoadBlob(context.TODO(), restic.DataBlob, id, buf)
buf, err := repo.LoadBlob(context.TODO(), restic.DataBlob, id, buf)
if err != nil {
t.Errorf("LoadBlob() returned an error for buffer size %v: %v", testlength, err)
continue
}
if n != length {
t.Errorf("LoadBlob() returned the wrong number of bytes: want %v, got %v", length, n)
if len(buf) != length {
t.Errorf("LoadBlob() returned the wrong number of bytes: want %v, got %v", length, len(buf))
continue
}
}
@ -213,13 +195,14 @@ func BenchmarkLoadBlob(b *testing.B) {
b.SetBytes(int64(length))
for i := 0; i < b.N; i++ {
n, err := repo.LoadBlob(context.TODO(), restic.DataBlob, id, buf)
var err error
buf, err = repo.LoadBlob(context.TODO(), restic.DataBlob, id, buf)
rtest.OK(b, err)
if n != length {
b.Errorf("wanted %d bytes, got %d", length, n)
if len(buf) != length {
b.Errorf("wanted %d bytes, got %d", length, len(buf))
}
id2 := restic.Hash(buf[:n])
id2 := restic.Hash(buf)
if !id.Equal(id2) {
b.Errorf("wrong data returned, wanted %v, got %v", id.Str(), id2.Str())
}

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@ -282,21 +282,10 @@ func (node Node) createFileAt(ctx context.Context, path string, repo Repository)
func (node Node) writeNodeContent(ctx context.Context, repo Repository, f *os.File) error {
var buf []byte
for _, id := range node.Content {
size, found := repo.LookupBlobSize(id, DataBlob)
if !found {
return errors.Errorf("id %v not found in repository", id)
}
buf = buf[:cap(buf)]
if len(buf) < CiphertextLength(int(size)) {
buf = NewBlobBuffer(int(size))
}
n, err := repo.LoadBlob(ctx, DataBlob, id, buf)
buf, err := repo.LoadBlob(ctx, DataBlob, id, buf)
if err != nil {
return err
}
buf = buf[:n]
_, err = f.Write(buf)
if err != nil {

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@ -45,7 +45,7 @@ type Repository interface {
// new buffer will be allocated and returned.
LoadAndDecrypt(ctx context.Context, buf []byte, t FileType, id ID) (data []byte, err error)
LoadBlob(context.Context, BlobType, ID, []byte) (int, error)
LoadBlob(context.Context, BlobType, ID, []byte) ([]byte, error)
SaveBlob(context.Context, BlobType, []byte, ID) (ID, error)
LoadTree(context.Context, ID) (*Tree, error)