From 790191ef92ec6382ce65cc30286c901863b3b7a3 Mon Sep 17 00:00:00 2001
From: Javi Fontan <jfontan@gmail.com>
Date: Wed, 22 Aug 2018 16:46:50 +0200
Subject: [PATCH] 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>
---
 plumbing/format/packfile/fsobject.go | 10 ++++++++++
 plumbing/format/packfile/packfile.go | 15 +++++++++++++++
 storage/filesystem/object.go         | 18 ++++++++++++++++--
 3 files changed, 41 insertions(+), 2 deletions(-)

diff --git a/plumbing/format/packfile/fsobject.go b/plumbing/format/packfile/fsobject.go
index 6fd3ca54d..330cb73c9 100644
--- a/plumbing/format/packfile/fsobject.go
+++ b/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
diff --git a/plumbing/format/packfile/packfile.go b/plumbing/format/packfile/packfile.go
index 18fcca7e8..852a8344b 100644
--- a/plumbing/format/packfile/packfile.go
+++ b/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
 }
 
diff --git a/storage/filesystem/object.go b/storage/filesystem/object.go
index 6958e3217..3a3a2bd97 100644
--- a/storage/filesystem/object.go
+++ b/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
 	}