core: new MemoryObject, move from memory.Object, packfile.Parser, base on new ObjectStorage interface

17 files changed, 199 insertions, 203 deletions

diff --git a/clients/http/common.go b/clients/http/common.go
index d375e62..e7c43d5 100644
--- a/clients/http/common.go
+++ b/clients/http/common.go
@@ -7,7 +7,6 @@ import (
 	"net/http"
 
 	"gopkg.in/src-d/go-git.v4/clients/common"
-
 	"gopkg.in/src-d/go-git.v4/core"
 )
 
diff --git a/core/memory.go b/core/memory.go
new file mode 100644
index 0000000..6477f74
--- /dev/null
+++ b/core/memory.go
@@ -0,0 +1,65 @@
+package core
+
+import (
+	"bytes"
+	"io/ioutil"
+)
+
+// MemoryObject on memory Object implementation
+type MemoryObject struct {
+	t    ObjectType
+	h    Hash
+	cont []byte
+	sz   int64
+}
+
+// NewMemoryObject creates a new MemoryObject
+func NewMemoryObject(t ObjectType, len int64, cont []byte) *MemoryObject {
+	return &MemoryObject{t: t, sz: len, cont: cont}
+}
+
+// Hash return the object Hash, the hash is calculated on-the-fly the first
+// time is called, the subsequent calls the same Hash is returned even if the
+// type or the content has changed. The Hash is only generated if the size of
+// the content is exactly the Object.Size
+func (o *MemoryObject) Hash() Hash {
+	if o.h == ZeroHash && int64(len(o.cont)) == o.sz {
+		o.h = ComputeHash(o.t, o.cont)
+	}
+
+	return o.h
+}
+
+// Type return the ObjectType
+func (o *MemoryObject) Type() ObjectType { return o.t }
+
+// SetType sets the ObjectType
+func (o *MemoryObject) SetType(t ObjectType) { o.t = t }
+
+// Size return the size of the object
+func (o *MemoryObject) Size() int64 { return o.sz }
+
+// SetSize set the object size, the given size should be written afterwards
+func (o *MemoryObject) SetSize(s int64) { o.sz = s }
+
+// Content returns the contents of the object
+func (o *MemoryObject) Content() []byte { return o.cont }
+
+// Reader returns a ObjectReader used to read the object's content.
+func (o *MemoryObject) Reader() (ObjectReader, error) {
+	return ioutil.NopCloser(bytes.NewBuffer(o.cont)), nil
+}
+
+// Writer returns a ObjectWriter used to write the object's content.
+func (o *MemoryObject) Writer() (ObjectWriter, error) {
+	return o, nil
+}
+
+func (o *MemoryObject) Write(p []byte) (n int, err error) {
+	o.cont = append(o.cont, p...)
+	return len(p), nil
+}
+
+// Close releases any resources consumed by the object when it is acting as a
+// ObjectWriter.
+func (o *MemoryObject) Close() error { return nil }
diff --git a/storage/memory/object_test.go b/core/memory_test.go
index c252626..f1c3f64 100644
--- a/storage/memory/object_test.go
+++ b/core/memory_test.go
@@ -1,22 +1,18 @@
-package memory
+package core
 
 import (
 	"io/ioutil"
-	"testing"
 
 	. "gopkg.in/check.v1"
-	"gopkg.in/src-d/go-git.v4/core"
 )
 
-func Test(t *testing.T) { TestingT(t) }
+type MemoryObjectSuite struct{}
 
-type ObjectSuite struct{}
+var _ = Suite(&MemoryObjectSuite{})
 
-var _ = Suite(&ObjectSuite{})
-
-func (s *ObjectSuite) TestHash(c *C) {
-	o := &Object{}
-	o.SetType(core.BlobObject)
+func (s *MemoryObjectSuite) TestHash(c *C) {
+	o := &MemoryObject{}
+	o.SetType(BlobObject)
 	o.SetSize(14)
 
 	_, err := o.Write([]byte("Hello, World!\n"))
@@ -24,32 +20,32 @@ func (s *ObjectSuite) TestHash(c *C) {
 
 	c.Assert(o.Hash().String(), Equals, "8ab686eafeb1f44702738c8b0f24f2567c36da6d")
 
-	o.SetType(core.CommitObject)
+	o.SetType(CommitObject)
 	c.Assert(o.Hash().String(), Equals, "8ab686eafeb1f44702738c8b0f24f2567c36da6d")
 }
 
-func (s *ObjectSuite) TestHashNotFilled(c *C) {
-	o := &Object{}
-	o.SetType(core.BlobObject)
+func (s *MemoryObjectSuite) TestHashNotFilled(c *C) {
+	o := &MemoryObject{}
+	o.SetType(BlobObject)
 	o.SetSize(14)
 
-	c.Assert(o.Hash(), Equals, core.ZeroHash)
+	c.Assert(o.Hash(), Equals, ZeroHash)
 }
 
-func (s *ObjectSuite) TestType(c *C) {
-	o := &Object{}
-	o.SetType(core.BlobObject)
-	c.Assert(o.Type(), Equals, core.BlobObject)
+func (s *MemoryObjectSuite) TestType(c *C) {
+	o := &MemoryObject{}
+	o.SetType(BlobObject)
+	c.Assert(o.Type(), Equals, BlobObject)
 }
 
-func (s *ObjectSuite) TestSize(c *C) {
-	o := &Object{}
+func (s *MemoryObjectSuite) TestSize(c *C) {
+	o := &MemoryObject{}
 	o.SetSize(42)
 	c.Assert(o.Size(), Equals, int64(42))
 }
 
-func (s *ObjectSuite) TestReader(c *C) {
-	o := &Object{cont: []byte("foo")}
+func (s *MemoryObjectSuite) TestReader(c *C) {
+	o := &MemoryObject{cont: []byte("foo")}
 
 	reader, err := o.Reader()
 	c.Assert(err, IsNil)
@@ -60,8 +56,8 @@ func (s *ObjectSuite) TestReader(c *C) {
 	c.Assert(b, DeepEquals, []byte("foo"))
 }
 
-func (s *ObjectSuite) TestWriter(c *C) {
-	o := &Object{}
+func (s *MemoryObjectSuite) TestWriter(c *C) {
+	o := &MemoryObject{}
 
 	writer, err := o.Writer()
 	c.Assert(err, IsNil)
diff --git a/core/object.go b/core/object.go
index 4610c45..01dd660 100644
--- a/core/object.go
+++ b/core/object.go
@@ -41,6 +41,7 @@ type Object interface {
 
 // ObjectStorage generic storage of objects
 type ObjectStorage interface {
+	NewObject() Object
 	Set(Object) (Hash, error)
 	Get(Hash) (Object, error)
 	Iter(ObjectType) (ObjectIter, error)
diff --git a/formats/packfile/decoder.go b/formats/packfile/decoder.go
index 2b5ef88..6d0cd8b 100644
--- a/formats/packfile/decoder.go
+++ b/formats/packfile/decoder.go
@@ -35,21 +35,8 @@ var (
 	ErrZLib = NewError("zlib reading error")
 )
 
-const (
-	// DefaultMaxObjectsLimit is the maximum amount of objects the
-	// decoder will decode before returning ErrMaxObjectsLimitReached.
-	DefaultMaxObjectsLimit = 1 << 20
-)
-
 // Decoder reads and decodes packfiles from an input stream.
 type Decoder struct {
-	// MaxObjectsLimit is the limit of objects to be load in the packfile, if
-	// a packfile excess this number an error is throw, the default value
-	// is defined by DefaultMaxObjectsLimit, usually the default limit is more
-	// than enough to work with any repository, with higher values and huge
-	// repositories you can run out of memory.
-	MaxObjectsLimit uint32
-
 	p *Parser
 	s core.ObjectStorage
 }
@@ -57,8 +44,6 @@ type Decoder struct {
 // NewDecoder returns a new Decoder that reads from r.
 func NewDecoder(r ReadRecaller) *Decoder {
 	return &Decoder{
-		MaxObjectsLimit: DefaultMaxObjectsLimit,
-
 		p: NewParser(r),
 	}
 }
@@ -72,13 +57,7 @@ func (d *Decoder) Decode(s core.ObjectStorage) error {
 		return err
 	}
 
-	if count > d.MaxObjectsLimit {
-		return ErrMaxObjectsLimitReached.AddDetails("%d", count)
-	}
-
-	err = d.readObjects(count)
-
-	return err
+	return d.readObjects(count)
 }
 
 func (d *Decoder) readObjects(count uint32) error {
@@ -92,8 +71,8 @@ func (d *Decoder) readObjects(count uint32) error {
 			return err
 		}
 
-		obj, err := d.p.ReadObject()
-		if err != nil {
+		obj := d.s.NewObject()
+		if err := d.p.FillObject(obj); err != nil {
 			if err == io.EOF {
 				break
 			}
diff --git a/formats/packfile/delta.go b/formats/packfile/delta.go
index e0bbb65..95c13d5 100644
--- a/formats/packfile/delta.go
+++ b/formats/packfile/delta.go
@@ -1,5 +1,7 @@
 package packfile
 
+import "gopkg.in/src-d/go-git.v4/core"
+
 // See https://github.com/git/git/blob/49fa3dc76179e04b0833542fa52d0f287a4955ac/delta.h
 // https://github.com/git/git/blob/c2c5f6b1e479f2c38e0e01345350620944e3527f/patch-delta.c,
 // and https://github.com/tarruda/node-git-core/blob/master/src/js/delta.js
@@ -7,6 +9,24 @@ package packfile
 
 const deltaSizeMin = 4
 
+// ApplyDelta writes to taget the result of applying the modification deltas in delta to base.
+func ApplyDelta(target, base core.Object, delta []byte) error {
+	src := base.Content()
+	w, err := target.Writer()
+	if err != nil {
+		return err
+	}
+
+	dst := PatchDelta(src, delta)
+	target.SetSize(int64(len(dst)))
+
+	if _, err := w.Write(dst); err != nil {
+		return err
+	}
+
+	return nil
+}
+
 // PatchDelta returns the result of applying the modification deltas in delta to src.
 func PatchDelta(src, delta []byte) []byte {
 	if len(delta) < deltaSizeMin {
diff --git a/formats/packfile/parser.go b/formats/packfile/parser.go
index a7c4047..8b7a692 100644
--- a/formats/packfile/parser.go
+++ b/formats/packfile/parser.go
@@ -8,7 +8,6 @@ import (
 	"io"
 
 	"gopkg.in/src-d/go-git.v4/core"
-	"gopkg.in/src-d/go-git.v4/storage/memory"
 )
 
 var (
@@ -30,6 +29,7 @@ const (
 // Values from this type are not zero-value safe. See the NewParser function bellow.
 type Parser struct {
 	ReadRecaller
+	ObjectFactory func() core.Object
 }
 
 // NewParser returns a new Parser that reads from the packfile represented by r.
@@ -174,47 +174,43 @@ func moreBytesInLength(c byte) bool {
 
 // ReadObject reads and returns a git object from an object entry in the packfile.
 // Non-deltified and deltified objects are supported.
-func (p Parser) ReadObject() (core.Object, error) {
+func (p Parser) FillObject(obj core.Object) error {
 	start, err := p.Offset()
 	if err != nil {
-		return nil, err
+		return err
 	}
 
-	var typ core.ObjectType
-	typ, _, err = p.ReadObjectTypeAndLength()
+	t, l, err := p.ReadObjectTypeAndLength()
 	if err != nil {
-		return nil, err
+		return err
 	}
 
-	var cont []byte
-	switch typ {
+	obj.SetSize(l)
+
+	switch t {
 	case core.CommitObject, core.TreeObject, core.BlobObject, core.TagObject:
-		cont, err = p.ReadNonDeltaObjectContent()
+		obj.SetType(t)
+		err = p.ReadNonDeltaObjectContent(obj)
 	case core.REFDeltaObject:
-		cont, typ, err = p.ReadREFDeltaObjectContent()
+		err = p.ReadREFDeltaObjectContent(obj)
 	case core.OFSDeltaObject:
-		cont, typ, err = p.ReadOFSDeltaObjectContent(start)
+		err = p.ReadOFSDeltaObjectContent(obj, start)
 	default:
-		err = ErrInvalidObject.AddDetails("tag %q", typ)
-	}
-	if err != nil {
-		return nil, err
+		err = ErrInvalidObject.AddDetails("tag %q", t)
 	}
 
-	return memory.NewObject(typ, int64(len(cont)), cont), nil
+	return err
 }
 
 // ReadNonDeltaObjectContent reads and returns a non-deltified object
 // from it zlib stream in an object entry in the packfile.
-func (p Parser) ReadNonDeltaObjectContent() ([]byte, error) {
-	return p.readZip()
-}
-
-func (p Parser) readZip() ([]byte, error) {
-	buf := bytes.NewBuffer(nil)
-	err := p.inflate(buf)
+func (p Parser) ReadNonDeltaObjectContent(obj core.Object) error {
+	w, err := obj.Writer()
+	if err != nil {
+		return err
+	}
 
-	return buf.Bytes(), err
+	return p.inflate(w)
 }
 
 func (p Parser) inflate(w io.Writer) (err error) {
@@ -239,23 +235,23 @@ func (p Parser) inflate(w io.Writer) (err error) {
 
 // ReadREFDeltaObjectContent reads and returns an object specified by a
 // REF-Delta entry in the packfile, form the hash onwards.
-func (p Parser) ReadREFDeltaObjectContent() ([]byte, core.ObjectType, error) {
+func (p Parser) ReadREFDeltaObjectContent(obj core.Object) error {
 	refHash, err := p.ReadHash()
 	if err != nil {
-		return nil, core.ObjectType(0), err
+		return err
 	}
 
-	refObj, err := p.RecallByHash(refHash)
+	base, err := p.RecallByHash(refHash)
 	if err != nil {
-		return nil, core.ObjectType(0), err
+		return err
 	}
 
-	content, err := p.ReadSolveDelta(refObj.Content())
-	if err != nil {
-		return nil, refObj.Type(), err
+	obj.SetType(base.Type())
+	if err := p.ReadAndApplyDelta(obj, base); err != nil {
+		return err
 	}
 
-	return content, refObj.Type(), nil
+	return nil
 }
 
 // ReadHash reads a hash.
@@ -268,41 +264,40 @@ func (p Parser) ReadHash() (core.Hash, error) {
 	return h, nil
 }
 
-// ReadSolveDelta reads and returns the base patched with the contents
+// ReadAndSolveDelta reads and returns the base patched with the contents
 // of a zlib compressed diff data in the delta portion of an object
 // entry in the packfile.
-func (p Parser) ReadSolveDelta(base []byte) ([]byte, error) {
-	diff, err := p.readZip()
-	if err != nil {
-		return nil, err
+func (p Parser) ReadAndApplyDelta(target, base core.Object) error {
+	buf := bytes.NewBuffer(nil)
+	if err := p.inflate(buf); err != nil {
+		return err
 	}
 
-	return PatchDelta(base, diff), nil
+	return ApplyDelta(target, base, buf.Bytes())
 }
 
 // ReadOFSDeltaObjectContent reads an returns an object specified by an
 // OFS-delta entry in the packfile from it negative offset onwards.  The
 // start parameter is the offset of this particular object entry (the
 // current offset minus the already processed type and length).
-func (p Parser) ReadOFSDeltaObjectContent(start int64) (
-	[]byte, core.ObjectType, error) {
+func (p Parser) ReadOFSDeltaObjectContent(obj core.Object, start int64) error {
 
 	jump, err := p.ReadNegativeOffset()
 	if err != nil {
-		return nil, core.ObjectType(0), err
+		return err
 	}
 
-	ref, err := p.RecallByOffset(start + jump)
+	base, err := p.RecallByOffset(start + jump)
 	if err != nil {
-		return nil, core.ObjectType(0), err
+		return err
 	}
 
-	content, err := p.ReadSolveDelta(ref.Content())
-	if err != nil {
-		return nil, ref.Type(), err
+	obj.SetType(base.Type())
+	if err := p.ReadAndApplyDelta(obj, base); err != nil {
+		return err
 	}
 
-	return content, ref.Type(), nil
+	return nil
 }
 
 // ReadNegativeOffset reads and returns an offset from a OFS DELTA
diff --git a/formats/packfile/parser_test.go b/formats/packfile/parser_test.go
index ec9b19a..c2b99f1 100644
--- a/formats/packfile/parser_test.go
+++ b/formats/packfile/parser_test.go
@@ -8,7 +8,6 @@ import (
 
 	. "gopkg.in/check.v1"
 	"gopkg.in/src-d/go-git.v4/core"
-	"gopkg.in/src-d/go-git.v4/storage/memory"
 )
 
 const (
@@ -238,9 +237,10 @@ func (s *ParserSuite) TestReadNonDeltaObjectContent(c *C) {
 		_, _, err = p.ReadObjectTypeAndLength()
 		c.Assert(err, IsNil, com)
 
-		cont, err := p.ReadNonDeltaObjectContent()
+		obj := &core.MemoryObject{}
+		err = p.ReadNonDeltaObjectContent(obj)
 		c.Assert(err, IsNil, com)
-		c.Assert(cont, DeepEquals, test.expected, com)
+		c.Assert(obj.Content(), DeepEquals, test.expected, com)
 	}
 }
 
@@ -293,10 +293,11 @@ func (s *ParserSuite) TestReadOFSDeltaObjectContent(c *C) {
 		err = fix.seek(beforeJumpSize)
 		c.Assert(err, IsNil, com)
 
-		cont, typ, err := p.ReadOFSDeltaObjectContent(test.offset)
+		obj := &core.MemoryObject{}
+		err = p.ReadOFSDeltaObjectContent(obj, test.offset)
 		c.Assert(err, IsNil, com)
-		c.Assert(typ, Equals, test.expType, com)
-		c.Assert(cont, DeepEquals, test.expContent, com)
+		c.Assert(obj.Type(), Equals, test.expType, com)
+		c.Assert(obj.Content(), DeepEquals, test.expContent, com)
 	}
 }
 
@@ -356,17 +357,18 @@ func (s *ParserSuite) TestReadREFDeltaObjectContent(c *C) {
 		err = fix.seek(beforeHash)
 		c.Assert(err, IsNil, com)
 
-		cont, typ, err := p.ReadREFDeltaObjectContent()
+		obj := &core.MemoryObject{}
+		err = p.ReadREFDeltaObjectContent(obj)
 		c.Assert(err, IsNil, com)
-		c.Assert(typ, Equals, test.expType, com)
-		c.Assert(cont, DeepEquals, test.expContent, com)
+		c.Assert(obj.Type(), Equals, test.expType, com)
+		c.Assert(obj.Content(), DeepEquals, test.expContent, com)
 
 		p.ForgetAll()
 	}
 }
 
-func newObject(t core.ObjectType, c []byte) *memory.Object {
-	return memory.NewObject(t, int64(len(c)), c)
+func newObject(t core.ObjectType, c []byte) core.Object {
+	return core.NewMemoryObject(t, int64(len(c)), c)
 }
 
 func (s *ParserSuite) TestReadHeaderBadSignatureError(c *C) {
diff --git a/formats/packfile/read_recaller_impl_test.go b/formats/packfile/read_recaller_impl_test.go
index 8de7e2a..f89171d 100644
--- a/formats/packfile/read_recaller_impl_test.go
+++ b/formats/packfile/read_recaller_impl_test.go
@@ -7,7 +7,6 @@ import (
 	"os"
 
 	"gopkg.in/src-d/go-git.v4/core"
-	"gopkg.in/src-d/go-git.v4/storage/memory"
 
 	. "gopkg.in/check.v1"
 )
@@ -152,20 +151,20 @@ func (s *ReadRecallerImplSuite) TestRememberRecall(c *C) {
 		}{
 			{
 				off: 12,
-				obj: newObj(core.CommitObject, []byte("tree 44a1cdf21c791867c51caad8f1b77e6baee6f462\nparent 87fe6e7c6b1b89519fe3a03a8961c5aa14d4cc68\nparent 9244ee648182b91a63d8cc4cbe4b9ac2a27c0492\nauthor Matt Duftler <duftler@google.com> 1448290941 -0500\ncommitter Matt Duftler <duftler@google.com> 1448290941 -0500\n\nMerge pull request #615 from ewiseblatt/create_dev\n\nPreserve original credentials of spinnaker-local.yml when transforming it.")),
+				obj: newObject(core.CommitObject, []byte("tree 44a1cdf21c791867c51caad8f1b77e6baee6f462\nparent 87fe6e7c6b1b89519fe3a03a8961c5aa14d4cc68\nparent 9244ee648182b91a63d8cc4cbe4b9ac2a27c0492\nauthor Matt Duftler <duftler@google.com> 1448290941 -0500\ncommitter Matt Duftler <duftler@google.com> 1448290941 -0500\n\nMerge pull request #615 from ewiseblatt/create_dev\n\nPreserve original credentials of spinnaker-local.yml when transforming it.")),
 			}, {
 				off: 3037,
-				obj: newObj(core.TagObject, []byte("object e0005f50e22140def60260960b21667f1fdfff80\ntype commit\ntag v0.10.0\ntagger cfieber <cfieber@netflix.com> 1447687536 -0800\n\nRelease of 0.10.0\n\n- e0005f50e22140def60260960b21667f1fdfff80: Merge pull request #553 from ewiseblatt/rendezvous\n- e1a2b26b784179e6903a7ae967c037c721899eba: Wait for cassandra before starting spinnaker\n- c756e09461d071e98b8660818cf42d90c90f2854: Merge pull request #552 from duftler/google-c2d-tweaks\n- 0777fadf4ca6f458d7071de414f9bd5417911037: Fix incorrect config prop names:   s/SPINNAKER_GOOGLE_PROJECT_DEFAULT_REGION/SPINNAKER_GOOGLE_DEFAULT_REGION   s/SPINNAKER_GOOGLE_PROJECT_DEFAULT_ZONE/SPINNAKER_GOOGLE_DEFAULT_ZONE Hardcode profile name in generated ~/.aws/credentials to [default]. Restart all of spinnaker after updating cassandra and reconfiguring spinnaker, instead of just restarting clouddriver.\n- d8d031c1ac45801074418c43424a6f2c0dff642c: Merge pull request #551 from kenzanmedia/fixGroup\n- 626d23075f9e92aad19015f2964c95d45f41fa3a: Put in correct block for public image. Delineate cloud provider.\n")),
+				obj: newObject(core.TagObject, []byte("object e0005f50e22140def60260960b21667f1fdfff80\ntype commit\ntag v0.10.0\ntagger cfieber <cfieber@netflix.com> 1447687536 -0800\n\nRelease of 0.10.0\n\n- e0005f50e22140def60260960b21667f1fdfff80: Merge pull request #553 from ewiseblatt/rendezvous\n- e1a2b26b784179e6903a7ae967c037c721899eba: Wait for cassandra before starting spinnaker\n- c756e09461d071e98b8660818cf42d90c90f2854: Merge pull request #552 from duftler/google-c2d-tweaks\n- 0777fadf4ca6f458d7071de414f9bd5417911037: Fix incorrect config prop names:   s/SPINNAKER_GOOGLE_PROJECT_DEFAULT_REGION/SPINNAKER_GOOGLE_DEFAULT_REGION   s/SPINNAKER_GOOGLE_PROJECT_DEFAULT_ZONE/SPINNAKER_GOOGLE_DEFAULT_ZONE Hardcode profile name in generated ~/.aws/credentials to [default]. Restart all of spinnaker after updating cassandra and reconfiguring spinnaker, instead of just restarting clouddriver.\n- d8d031c1ac45801074418c43424a6f2c0dff642c: Merge pull request #551 from kenzanmedia/fixGroup\n- 626d23075f9e92aad19015f2964c95d45f41fa3a: Put in correct block for public image. Delineate cloud provider.\n")),
 			}, {
 				off: 157625,
-				obj: newObj(core.BlobObject, []byte(".gradle\nbuild/\n*.iml\n.idea\n*.pyc\n*~\n#*\nconfig/spinnaker-local.yml\n.DS_Store\npacker/ami_table.md\npacker/ami_table.json\npacker/example_output.txt")),
+				obj: newObject(core.BlobObject, []byte(".gradle\nbuild/\n*.iml\n.idea\n*.pyc\n*~\n#*\nconfig/spinnaker-local.yml\n.DS_Store\npacker/ami_table.md\npacker/ami_table.json\npacker/example_output.txt")),
 			}, {
 				off: 1234,
-				obj: newObj(core.BlobObject, []byte(".gradle\nbuild/\n*.iml\n.idea\n*.pyc\n*~\n#*\nconfig/spinnaker-local.yml\n.DS_Store\npacker/ami_table.md\npacker/ami_table.json\npacker/example_output.txt")),
+				obj: newObject(core.BlobObject, []byte(".gradle\nbuild/\n*.iml\n.idea\n*.pyc\n*~\n#*\nconfig/spinnaker-local.yml\n.DS_Store\npacker/ami_table.md\npacker/ami_table.json\npacker/example_output.txt")),
 				err: "duplicated object: with hash .*",
 			}, {
 				off:    3037,
-				obj:    newObj(core.BlobObject, []byte("")),
+				obj:    newObject(core.BlobObject, []byte("")),
 				err:    "duplicated object: with offset 3037",
 				ignore: "seekable",
 				// seekable can not check if the offset has already been added
@@ -186,19 +185,17 @@ func (s *ReadRecallerImplSuite) TestRememberRecall(c *C) {
 
 			result, err := sr.RecallByHash(test.obj.Hash())
 			c.Assert(err, IsNil, com)
+			c.Assert(result.Hash(), Equals, test.obj.Hash())
 			c.Assert(result, DeepEquals, test.obj, com)
 
 			result, err = sr.RecallByOffset(test.off)
 			c.Assert(err, IsNil, com)
+			c.Assert(result.Hash(), Equals, test.obj.Hash())
 			c.Assert(result, DeepEquals, test.obj, com)
 		}
 	}
 }
 
-func newObj(typ core.ObjectType, cont []byte) core.Object {
-	return memory.NewObject(typ, int64(len(cont)), cont)
-}
-
 func (s *ReadRecallerImplSuite) TestRecallByHashErrors(c *C) {
 	for _, impl := range []struct {
 		id    string
@@ -209,7 +206,7 @@ func (s *ReadRecallerImplSuite) TestRecallByHashErrors(c *C) {
 	} {
 		com := Commentf("implementation %s", impl.id)
 		sr := impl.newFn([]byte{})
-		obj := newObj(core.CommitObject, []byte{})
+		obj := newObject(core.CommitObject, []byte{})
 
 		_, err := sr.RecallByHash(obj.Hash())
 		c.Assert(err, ErrorMatches, ErrCannotRecall.Error()+".*", com)
@@ -249,9 +246,9 @@ func rememberSomeObjects(sr ReadRecaller) error {
 		off int64
 		obj core.Object
 	}{
-		{off: 0, obj: newObj(core.CommitObject, []byte{'a'})},  // 93114cce67ec23976d15199514399203f69cc676
-		{off: 10, obj: newObj(core.CommitObject, []byte{'b'})}, // 2bb767097e479f668f0ebdabe88df11337bd8f19
-		{off: 20, obj: newObj(core.CommitObject, []byte{'c'})}, // 2f8096005677370e6446541a50e074299d43d468
+		{off: 0, obj: newObject(core.CommitObject, []byte{'a'})},  // 93114cce67ec23976d15199514399203f69cc676
+		{off: 10, obj: newObject(core.CommitObject, []byte{'b'})}, // 2bb767097e479f668f0ebdabe88df11337bd8f19
+		{off: 20, obj: newObject(core.CommitObject, []byte{'c'})}, // 2f8096005677370e6446541a50e074299d43d468
 	} {
 		err := sr.Remember(init.off, init.obj)
 		if err != nil {
diff --git a/formats/packfile/seekable.go b/formats/packfile/seekable.go
index 37b4ee9..65c8a69 100644
--- a/formats/packfile/seekable.go
+++ b/formats/packfile/seekable.go
@@ -104,5 +104,6 @@ func (r *Seekable) RecallByOffset(o int64) (obj core.Object, err error) {
 		return nil, err
 	}
 
-	return NewParser(r).ReadObject()
+	obj = &core.MemoryObject{}
+	return obj, NewParser(r).FillObject(obj)
 }
diff --git a/objects_test.go b/objects_test.go
index 4aa835d..80ebf7f 100644
--- a/objects_test.go
+++ b/objects_test.go
@@ -5,7 +5,6 @@ import (
 	"time"
 
 	"gopkg.in/src-d/go-git.v4/core"
-	"gopkg.in/src-d/go-git.v4/storage/memory"
 
 	. "gopkg.in/check.v1"
 )
@@ -83,7 +82,7 @@ func (s *ObjectsSuite) TestParseTree(c *C) {
 }
 
 func (s *ObjectsSuite) TestBlobHash(c *C) {
-	o := &memory.Object{}
+	o := &core.MemoryObject{}
 	o.SetType(core.BlobObject)
 	o.SetSize(3)
 
diff --git a/storage/memory/object.go b/storage/memory/object.go
deleted file mode 100644
index 8c35360..0000000
--- a/storage/memory/object.go
+++ /dev/null
@@ -1,72 +0,0 @@
-package memory
-
-import (
-	"bytes"
-	"io/ioutil"
-
-	"gopkg.in/src-d/go-git.v4/core"
-)
-
-// Object on memory core.Object implementation
-type Object struct {
-	t    core.ObjectType
-	h    core.Hash
-	cont []byte
-	sz   int64
-}
-
-// NewObject creates a new object with the given type and content
-func NewObject(typ core.ObjectType, size int64, cont []byte) *Object {
-	return &Object{
-		t:    typ,
-		h:    core.ComputeHash(typ, cont),
-		cont: cont,
-		sz:   int64(len(cont)),
-	}
-}
-
-// Hash return the object Hash, the hash is calculated on-the-fly the first
-// time is called, the subsequent calls the same Hash is returned even if the
-// type or the content has changed. The Hash is only generated if the size of
-// the content is exactly the Object.Size
-func (o *Object) Hash() core.Hash {
-	if o.h == core.ZeroHash && int64(len(o.cont)) == o.sz {
-		o.h = core.ComputeHash(o.t, o.cont)
-	}
-
-	return o.h
-}
-
-// Type return the core.ObjectType
-func (o *Object) Type() core.ObjectType { return o.t }
-
-// SetType sets the core.ObjectType
-func (o *Object) SetType(t core.ObjectType) { o.t = t }
-
-// Size return the size of the object
-func (o *Object) Size() int64 { return o.sz }
-
-// SetSize set the object size, the given size should be written afterwards
-func (o *Object) SetSize(s int64) { o.sz = s }
-
-// Content returns the contents of the object
-func (o *Object) Content() []byte { return o.cont }
-
-// Reader returns a core.ObjectReader used to read the object's content.
-func (o *Object) Reader() (core.ObjectReader, error) {
-	return ioutil.NopCloser(bytes.NewBuffer(o.cont)), nil
-}
-
-// Writer returns a core.ObjectWriter used to write the object's content.
-func (o *Object) Writer() (core.ObjectWriter, error) {
-	return o, nil
-}
-
-func (o *Object) Write(p []byte) (n int, err error) {
-	o.cont = append(o.cont, p...)
-	return len(p), nil
-}
-
-// Close releases any resources consumed by the object when it is acting as a
-// core.ObjectWriter.
-func (o *Object) Close() error { return nil }
diff --git a/storage/memory/storage.go b/storage/memory/storage.go
index 62fd1b4..c827ce0 100644
--- a/storage/memory/storage.go
+++ b/storage/memory/storage.go
@@ -28,6 +28,11 @@ func NewObjectStorage() *ObjectStorage {
 	}
 }
 
+// NewObject creates a new MemoryObject
+func (o *ObjectStorage) NewObject() core.Object {
+	return &core.MemoryObject{}
+}
+
 // Set stores an object, the object should be properly filled before set it.
 func (o *ObjectStorage) Set(obj core.Object) (core.Hash, error) {
 	h := obj.Hash()
diff --git a/storage/memory/storage_test.go b/storage/memory/storage_test.go
index 200dbba..3b6c994 100644
--- a/storage/memory/storage_test.go
+++ b/storage/memory/storage_test.go
@@ -1,10 +1,14 @@
 package memory
 
 import (
+	"testing"
+
 	. "gopkg.in/check.v1"
 	"gopkg.in/src-d/go-git.v4/core"
 )
 
+func Test(t *testing.T) { TestingT(t) }
+
 type ObjectStorageSuite struct{}
 
 var _ = Suite(&ObjectStorageSuite{})
@@ -12,7 +16,7 @@ var _ = Suite(&ObjectStorageSuite{})
 func (s *ObjectStorageSuite) TestSet(c *C) {
 	os := NewObjectStorage()
 
-	o := &Object{}
+	o := &core.MemoryObject{}
 	o.SetType(core.CommitObject)
 	o.SetSize(3)
 
@@ -30,7 +34,7 @@ func (s *ObjectStorageSuite) TestSet(c *C) {
 func (s *ObjectStorageSuite) TestGet(c *C) {
 	os := NewObjectStorage()
 
-	o := &Object{}
+	o := &core.MemoryObject{}
 	o.SetType(core.CommitObject)
 	o.SetSize(3)
 
diff --git a/storage/seekable/internal/index/index.go b/storage/seekable/internal/index/index.go
index 4282f3e..737aca6 100644
--- a/storage/seekable/internal/index/index.go
+++ b/storage/seekable/internal/index/index.go
@@ -51,8 +51,8 @@ func NewFromPackfile(rs io.ReadSeeker) (Index, error) {
 			return nil, err
 		}
 
-		obj, err := p.ReadObject()
-		if err != nil {
+		obj := &core.MemoryObject{}
+		if err := p.FillObject(obj); err != nil {
 			return nil, err
 		}
 
diff --git a/storage/seekable/storage.go b/storage/seekable/storage.go
index 9cc37ba..e056c54 100644
--- a/storage/seekable/storage.go
+++ b/storage/seekable/storage.go
@@ -90,6 +90,10 @@ func buildIndexFromIdxfile(fs fs.FS, path string) (index.Index, error) {
 	return index.NewFromIdx(f)
 }
 
+func (s *ObjectStorage) NewObject() core.Object {
+	return &core.MemoryObject{}
+}
+
 // Set adds a new object to the storage. As this functionality is not
 // yet supported, this method always returns a "not implemented yet"
 // error an zero hash.
@@ -131,7 +135,8 @@ func (s *ObjectStorage) Get(h core.Hash) (core.Object, error) {
 	r.HashToOffset = map[core.Hash]int64(s.index)
 	p := packfile.NewParser(r)
 
-	return p.ReadObject()
+	obj := s.NewObject()
+	return obj, p.FillObject(obj)
 }
 
 // Iter returns an iterator for all the objects in the packfile with the
diff --git a/storage/seekable/storage_test.go b/storage/seekable/storage_test.go
index 2002d2b..bd12ed1 100644
--- a/storage/seekable/storage_test.go
+++ b/storage/seekable/storage_test.go
@@ -321,6 +321,6 @@ func (s *FsSuite) TestSet(c *C) {
 	sto, err := seekable.New(fs, gitPath)
 	c.Assert(err, IsNil)
 
-	_, err = sto.Set(&memory.Object{})
+	_, err = sto.Set(&core.MemoryObject{})
 	c.Assert(err, ErrorMatches, "not implemented yet")
 }