plumbing, storage: add bases to the common cache

After clone only resolved deltas were added to the cache. This caused
slowdowns in small repositories where most objects can be held in cache.

It also makes packfiles reuse delta cache from the store. Previously it
created a new delta cache each time a packfile object was created. This
also slowed down a bit accessing objects and had an impact on memory
consumption when bases are added to the cache.

Signed-off-by: Javi Fontan <jfontan@gmail.com>

Author: jfontan

plumbing/format/packfile/fsobject.go

@@ -47,6 +47,16 @@ func NewFSObject(
 
 // Reader implements the plumbing.EncodedObject interface.
 func (o *FSObject) Reader() (io.ReadCloser, error) {
+	obj, ok := o.cache.Get(o.hash)
+	if ok {
+		reader, err := obj.Reader()
+		if err != nil {
+			return nil, err
+		}
+
+		return reader, nil
+	}
+
 	f, err := o.fs.Open(o.path)
 	if err != nil {
 		return nil, err

plumbing/format/packfile/packfile.go

@@ -258,6 +258,19 @@ func (p *Packfile) nextObject() (plumbing.EncodedObject, error) {
 }
 
 func (p *Packfile) getObjectContent(offset int64) (io.ReadCloser, error) {
+	ref, err := p.FindHash(offset)
+	if err == nil {
+		obj, ok := p.cacheGet(ref)
+		if ok {
+			reader, err := obj.Reader()
+			if err != nil {
+				return nil, err
+			}
+
+			return reader, nil
+		}
+	}
+
 	if _, err := p.s.SeekFromStart(offset); err != nil {
 		return nil, err
 	}
@@ -306,6 +319,8 @@ func (p *Packfile) fillRegularObjectContent(obj plumbing.EncodedObject) error {
 	}
 
 	_, _, err = p.s.NextObject(w)
+	p.cachePut(obj)
+
 	return err
 }
 

storage/filesystem/object.go

@@ -295,7 +295,14 @@ func (s *ObjectStorage) decodeObjectAt(
 		return nil, err
 	}
 
-	return packfile.NewPackfile(idx, s.dir.Fs(), f).GetByOffset(offset)
+	var p *packfile.Packfile
+	if s.deltaBaseCache != nil {
+		p = packfile.NewPackfileWithCache(idx, s.dir.Fs(), f, s.deltaBaseCache)
+	} else {
+		p = packfile.NewPackfile(idx, s.dir.Fs(), f)
+	}
+
+	return p.GetByOffset(offset)
 }
 
 func (s *ObjectStorage) decodeDeltaObjectAt(
@@ -486,7 +493,14 @@ func newPackfileIter(
 	index idxfile.Index,
 	cache cache.Object,
 ) (storer.EncodedObjectIter, error) {
-	iter, err := packfile.NewPackfile(index, fs, f).GetByType(t)
+	var p *packfile.Packfile
+	if cache != nil {
+		p = packfile.NewPackfileWithCache(index, fs, f, cache)
+	} else {
+		p = packfile.NewPackfile(index, fs, f)
+	}
+
+	iter, err := p.GetByType(t)
 	if err != nil {
 		return nil, err
 	}