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-rw-r--r--plumbing/format/packfile/decoder.go495
1 files changed, 0 insertions, 495 deletions
diff --git a/plumbing/format/packfile/decoder.go b/plumbing/format/packfile/decoder.go
deleted file mode 100644
index f706e5d..0000000
--- a/plumbing/format/packfile/decoder.go
+++ /dev/null
@@ -1,495 +0,0 @@
-package packfile
-
-import (
- "bytes"
-
- "gopkg.in/src-d/go-git.v4/plumbing"
- "gopkg.in/src-d/go-git.v4/plumbing/cache"
- "gopkg.in/src-d/go-git.v4/plumbing/storer"
-)
-
-// Format specifies if the packfile uses ref-deltas or ofs-deltas.
-type Format int
-
-// Possible values of the Format type.
-const (
- UnknownFormat Format = iota
- OFSDeltaFormat
- REFDeltaFormat
-)
-
-var (
- // ErrMaxObjectsLimitReached is returned by Decode when the number
- // of objects in the packfile is higher than
- // Decoder.MaxObjectsLimit.
- ErrMaxObjectsLimitReached = NewError("max. objects limit reached")
- // ErrInvalidObject is returned by Decode when an invalid object is
- // found in the packfile.
- ErrInvalidObject = NewError("invalid git object")
- // ErrPackEntryNotFound is returned by Decode when a reference in
- // the packfile references and unknown object.
- ErrPackEntryNotFound = NewError("can't find a pack entry")
- // ErrZLib is returned by Decode when there was an error unzipping
- // the packfile contents.
- ErrZLib = NewError("zlib reading error")
- // ErrCannotRecall is returned by RecallByOffset or RecallByHash if the object
- // to recall cannot be returned.
- ErrCannotRecall = NewError("cannot recall object")
- // ErrResolveDeltasNotSupported is returned if a NewDecoder is used with a
- // non-seekable scanner and without a plumbing.ObjectStorage
- ErrResolveDeltasNotSupported = NewError("resolve delta is not supported")
- // ErrNonSeekable is returned if a ReadObjectAt method is called without a
- // seekable scanner
- ErrNonSeekable = NewError("non-seekable scanner")
- // ErrRollback error making Rollback over a transaction after an error
- ErrRollback = NewError("rollback error, during set error")
- // ErrAlreadyDecoded is returned if NewDecoder is called for a second time
- ErrAlreadyDecoded = NewError("packfile was already decoded")
-)
-
-// Decoder reads and decodes packfiles from an input Scanner, if an ObjectStorer
-// was provided the decoded objects are store there. If not the decode object
-// is destroyed. The Offsets and CRCs are calculated whether an
-// ObjectStorer was provided or not.
-type Decoder struct {
- deltaBaseCache cache.Object
-
- s *Scanner
- o storer.EncodedObjectStorer
- tx storer.Transaction
-
- isDecoded bool
-
- // hasBuiltIndex indicates if the index is fully built or not. If it is not,
- // will be built incrementally while decoding.
- hasBuiltIndex bool
- idx *Index
-
- offsetToType map[int64]plumbing.ObjectType
- decoderType plumbing.ObjectType
-}
-
-// NewDecoder returns a new Decoder that decodes a Packfile using the given
-// Scanner and stores the objects in the provided EncodedObjectStorer. ObjectStorer can be nil, in this
-// If the passed EncodedObjectStorer is nil, objects are not stored, but
-// offsets on the Packfile and CRCs are calculated.
-//
-// If EncodedObjectStorer is nil and the Scanner is not Seekable, ErrNonSeekable is
-// returned.
-//
-// If the ObjectStorer implements storer.Transactioner, a transaction is created
-// during the Decode execution. If anything fails, Rollback is called
-func NewDecoder(s *Scanner, o storer.EncodedObjectStorer) (*Decoder, error) {
- return NewDecoderForType(s, o, plumbing.AnyObject,
- cache.NewObjectLRUDefault())
-}
-
-// NewDecoderWithCache is a version of NewDecoder where cache can be specified.
-func NewDecoderWithCache(s *Scanner, o storer.EncodedObjectStorer,
- cacheObject cache.Object) (*Decoder, error) {
-
- return NewDecoderForType(s, o, plumbing.AnyObject, cacheObject)
-}
-
-// NewDecoderForType returns a new Decoder but in this case for a specific object type.
-// When an object is read using this Decoder instance and it is not of the same type of
-// the specified one, nil will be returned. This is intended to avoid the content
-// deserialization of all the objects.
-//
-// cacheObject is a cache.Object implementation that is used to speed up the
-// process. If cache is not needed you can pass nil. To create an LRU cache
-// object with the default size you can use the helper cache.ObjectLRUDefault().
-func NewDecoderForType(s *Scanner, o storer.EncodedObjectStorer,
- t plumbing.ObjectType, cacheObject cache.Object) (*Decoder, error) {
-
- if t == plumbing.OFSDeltaObject ||
- t == plumbing.REFDeltaObject ||
- t == plumbing.InvalidObject {
- return nil, plumbing.ErrInvalidType
- }
-
- if !canResolveDeltas(s, o) {
- return nil, ErrResolveDeltasNotSupported
- }
-
- return &Decoder{
- s: s,
- o: o,
- deltaBaseCache: cacheObject,
-
- idx: NewIndex(0),
- offsetToType: make(map[int64]plumbing.ObjectType),
- decoderType: t,
- }, nil
-}
-
-func canResolveDeltas(s *Scanner, o storer.EncodedObjectStorer) bool {
- return s.IsSeekable || o != nil
-}
-
-// Decode reads a packfile and stores it in the value pointed to by s. The
-// offsets and the CRCs are calculated by this method
-func (d *Decoder) Decode() (checksum plumbing.Hash, err error) {
- defer func() { d.isDecoded = true }()
-
- if d.isDecoded {
- return plumbing.ZeroHash, ErrAlreadyDecoded
- }
-
- if err := d.doDecode(); err != nil {
- return plumbing.ZeroHash, err
- }
-
- return d.s.Checksum()
-}
-
-func (d *Decoder) doDecode() error {
- _, count, err := d.s.Header()
- if err != nil {
- return err
- }
-
- if !d.hasBuiltIndex {
- d.idx = NewIndex(int(count))
- }
- defer func() { d.hasBuiltIndex = true }()
-
- _, isTxStorer := d.o.(storer.Transactioner)
- switch {
- case d.o == nil:
- return d.decodeObjects(int(count))
- case isTxStorer:
- return d.decodeObjectsWithObjectStorerTx(int(count))
- default:
- return d.decodeObjectsWithObjectStorer(int(count))
- }
-}
-
-func (d *Decoder) decodeObjects(count int) error {
- for i := 0; i < count; i++ {
- if _, err := d.DecodeObject(); err != nil {
- return err
- }
- }
-
- return nil
-}
-
-func (d *Decoder) decodeObjectsWithObjectStorer(count int) error {
- for i := 0; i < count; i++ {
- obj, err := d.DecodeObject()
- if err != nil {
- return err
- }
-
- if _, err := d.o.SetEncodedObject(obj); err != nil {
- return err
- }
- }
-
- return nil
-}
-
-func (d *Decoder) decodeObjectsWithObjectStorerTx(count int) error {
- d.tx = d.o.(storer.Transactioner).Begin()
-
- for i := 0; i < count; i++ {
- obj, err := d.DecodeObject()
- if err != nil {
- return err
- }
-
- if _, err := d.tx.SetEncodedObject(obj); err != nil {
- if rerr := d.tx.Rollback(); rerr != nil {
- return ErrRollback.AddDetails(
- "error: %s, during tx.Set error: %s", rerr, err,
- )
- }
-
- return err
- }
-
- }
-
- return d.tx.Commit()
-}
-
-// DecodeObject reads the next object from the scanner and returns it. This
-// method can be used in replacement of the Decode method, to work in a
-// interactive way. If you created a new decoder instance using NewDecoderForType
-// constructor, if the object decoded is not equals to the specified one, nil will
-// be returned
-func (d *Decoder) DecodeObject() (plumbing.EncodedObject, error) {
- return d.doDecodeObject(d.decoderType)
-}
-
-func (d *Decoder) doDecodeObject(t plumbing.ObjectType) (plumbing.EncodedObject, error) {
- h, err := d.s.NextObjectHeader()
- if err != nil {
- return nil, err
- }
-
- if t == plumbing.AnyObject {
- return d.decodeByHeader(h)
- }
-
- return d.decodeIfSpecificType(h)
-}
-
-func (d *Decoder) decodeIfSpecificType(h *ObjectHeader) (plumbing.EncodedObject, error) {
- var (
- obj plumbing.EncodedObject
- realType plumbing.ObjectType
- err error
- )
- switch h.Type {
- case plumbing.OFSDeltaObject:
- realType, err = d.ofsDeltaType(h.OffsetReference)
- case plumbing.REFDeltaObject:
- realType, err = d.refDeltaType(h.Reference)
- if err == plumbing.ErrObjectNotFound {
- obj, err = d.decodeByHeader(h)
- if err != nil {
- realType = obj.Type()
- }
- }
- default:
- realType = h.Type
- }
-
- if err != nil {
- return nil, err
- }
-
- d.offsetToType[h.Offset] = realType
-
- if d.decoderType == realType {
- if obj != nil {
- return obj, nil
- }
-
- return d.decodeByHeader(h)
- }
-
- return nil, nil
-}
-
-func (d *Decoder) ofsDeltaType(offset int64) (plumbing.ObjectType, error) {
- t, ok := d.offsetToType[offset]
- if !ok {
- return plumbing.InvalidObject, plumbing.ErrObjectNotFound
- }
-
- return t, nil
-}
-
-func (d *Decoder) refDeltaType(ref plumbing.Hash) (plumbing.ObjectType, error) {
- e, ok := d.idx.LookupHash(ref)
- if !ok {
- return plumbing.InvalidObject, plumbing.ErrObjectNotFound
- }
-
- return d.ofsDeltaType(int64(e.Offset))
-}
-
-func (d *Decoder) decodeByHeader(h *ObjectHeader) (plumbing.EncodedObject, error) {
- obj := d.newObject()
- obj.SetSize(h.Length)
- obj.SetType(h.Type)
-
- var crc uint32
- var err error
- switch h.Type {
- case plumbing.CommitObject, plumbing.TreeObject, plumbing.BlobObject, plumbing.TagObject:
- crc, err = d.fillRegularObjectContent(obj)
- case plumbing.REFDeltaObject:
- crc, err = d.fillREFDeltaObjectContent(obj, h.Reference)
- case plumbing.OFSDeltaObject:
- crc, err = d.fillOFSDeltaObjectContent(obj, h.OffsetReference)
- default:
- err = ErrInvalidObject.AddDetails("type %q", h.Type)
- }
-
- if err != nil {
- return obj, err
- }
-
- if !d.hasBuiltIndex {
- d.idx.Add(obj.Hash(), uint64(h.Offset), crc)
- }
-
- return obj, nil
-}
-
-func (d *Decoder) newObject() plumbing.EncodedObject {
- if d.o == nil {
- return &plumbing.MemoryObject{}
- }
-
- return d.o.NewEncodedObject()
-}
-
-// DecodeObjectAt reads an object at the given location. Every EncodedObject
-// returned is added into a internal index. This is intended to be able to regenerate
-// objects from deltas (offset deltas or reference deltas) without an package index
-// (.idx file). If Decode wasn't called previously objects offset should provided
-// using the SetOffsets method. It decodes the object regardless of the Decoder
-// type.
-func (d *Decoder) DecodeObjectAt(offset int64) (plumbing.EncodedObject, error) {
- if !d.s.IsSeekable {
- return nil, ErrNonSeekable
- }
-
- beforeJump, err := d.s.SeekFromStart(offset)
- if err != nil {
- return nil, err
- }
-
- defer func() {
- _, seekErr := d.s.SeekFromStart(beforeJump)
- if err == nil {
- err = seekErr
- }
- }()
-
- return d.doDecodeObject(plumbing.AnyObject)
-}
-
-func (d *Decoder) fillRegularObjectContent(obj plumbing.EncodedObject) (uint32, error) {
- w, err := obj.Writer()
- if err != nil {
- return 0, err
- }
-
- _, crc, err := d.s.NextObject(w)
- return crc, err
-}
-
-func (d *Decoder) fillREFDeltaObjectContent(obj plumbing.EncodedObject, ref plumbing.Hash) (uint32, error) {
- buf := bufPool.Get().(*bytes.Buffer)
- buf.Reset()
- _, crc, err := d.s.NextObject(buf)
- if err != nil {
- return 0, err
- }
-
- base, ok := d.cacheGet(ref)
- if !ok {
- base, err = d.recallByHash(ref)
- if err != nil {
- return 0, err
- }
- }
-
- obj.SetType(base.Type())
- err = ApplyDelta(obj, base, buf.Bytes())
- d.cachePut(obj)
- bufPool.Put(buf)
-
- return crc, err
-}
-
-func (d *Decoder) fillOFSDeltaObjectContent(obj plumbing.EncodedObject, offset int64) (uint32, error) {
- buf := bytes.NewBuffer(nil)
- _, crc, err := d.s.NextObject(buf)
- if err != nil {
- return 0, err
- }
-
- e, ok := d.idx.LookupOffset(uint64(offset))
- var base plumbing.EncodedObject
- if ok {
- base, ok = d.cacheGet(e.Hash)
- }
-
- if !ok {
- base, err = d.recallByOffset(offset)
- if err != nil {
- return 0, err
- }
-
- d.cachePut(base)
- }
-
- obj.SetType(base.Type())
- err = ApplyDelta(obj, base, buf.Bytes())
- d.cachePut(obj)
-
- return crc, err
-}
-
-func (d *Decoder) cacheGet(h plumbing.Hash) (plumbing.EncodedObject, bool) {
- if d.deltaBaseCache == nil {
- return nil, false
- }
-
- return d.deltaBaseCache.Get(h)
-}
-
-func (d *Decoder) cachePut(obj plumbing.EncodedObject) {
- if d.deltaBaseCache == nil {
- return
- }
-
- d.deltaBaseCache.Put(obj)
-}
-
-func (d *Decoder) recallByOffset(o int64) (plumbing.EncodedObject, error) {
- if d.s.IsSeekable {
- return d.DecodeObjectAt(o)
- }
-
- if e, ok := d.idx.LookupOffset(uint64(o)); ok {
- return d.recallByHashNonSeekable(e.Hash)
- }
-
- return nil, plumbing.ErrObjectNotFound
-}
-
-func (d *Decoder) recallByHash(h plumbing.Hash) (plumbing.EncodedObject, error) {
- if d.s.IsSeekable {
- if e, ok := d.idx.LookupHash(h); ok {
- return d.DecodeObjectAt(int64(e.Offset))
- }
- }
-
- return d.recallByHashNonSeekable(h)
-}
-
-// recallByHashNonSeekable if we are in a transaction the objects are read from
-// the transaction, if not are directly read from the ObjectStorer
-func (d *Decoder) recallByHashNonSeekable(h plumbing.Hash) (obj plumbing.EncodedObject, err error) {
- if d.tx != nil {
- obj, err = d.tx.EncodedObject(plumbing.AnyObject, h)
- } else {
- obj, err = d.o.EncodedObject(plumbing.AnyObject, h)
- }
-
- if err != plumbing.ErrObjectNotFound {
- return obj, err
- }
-
- return nil, plumbing.ErrObjectNotFound
-}
-
-// SetIndex sets an index for the packfile. It is recommended to set this.
-// The index might be read from a file or reused from a previous Decoder usage
-// (see Index function).
-func (d *Decoder) SetIndex(idx *Index) {
- d.hasBuiltIndex = true
- d.idx = idx
-}
-
-// Index returns the index for the packfile. If index was set with SetIndex,
-// Index will return it. Otherwise, it will return an index that is built while
-// decoding. If neither SetIndex was called with a full index or Decode called
-// for the whole packfile, then the returned index will be incomplete.
-func (d *Decoder) Index() *Index {
- return d.idx
-}
-
-// Close closes the Scanner. usually this mean that the whole reader is read and
-// discarded
-func (d *Decoder) Close() error {
- return d.s.Close()
-}