storage: shallow storage (#180)

* storage: shallow storage

* changes

* changes

2 files changed, 89 insertions, 1 deletions

diff --git a/storage/filesystem/internal/dotgit/dotgit.go b/storage/filesystem/internal/dotgit/dotgit.go
index 3a6227e..3405908 100644
--- a/storage/filesystem/internal/dotgit/dotgit.go
+++ b/storage/filesystem/internal/dotgit/dotgit.go
@@ -17,6 +17,7 @@ const (
 	suffix         = ".git"
 	packedRefsPath = "packed-refs"
 	configPath     = "config"
+	shallowPath    = "shallow"
 
 	objectsPath = "objects"
 	packPath    = "pack"
@@ -60,15 +61,35 @@ func New(fs fs.Filesystem) *DotGit {
 	return &DotGit{fs: fs}
 }
 
+// ConfigWriter returns a file pointer for write to the config file
 func (d *DotGit) ConfigWriter() (fs.File, error) {
 	return d.fs.Create(configPath)
 }
 
-// Config returns the path of the config file
+// Config returns a file pointer for read to the config file
 func (d *DotGit) Config() (fs.File, error) {
 	return d.fs.Open(configPath)
 }
 
+// ShallowWriter returns a file pointer for write to the shallow file
+func (d *DotGit) ShallowWriter() (fs.File, error) {
+	return d.fs.Create(shallowPath)
+}
+
+// Shallow returns a file pointer for read to the shallow file
+func (d *DotGit) Shallow() (fs.File, error) {
+	f, err := d.fs.Open(shallowPath)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return nil, nil
+		}
+
+		return nil, err
+	}
+
+	return f, nil
+}
+
 // NewObjectPack return a writer for a new packfile, it saves the packfile to
 // disk and also generates and save the index for the given packfile.
 func (d *DotGit) NewObjectPack() (*PackWriter, error) {
diff --git a/storage/filesystem/internal/dotgit/dotgit_test.go b/storage/filesystem/internal/dotgit/dotgit_test.go
index 3a1f194..b645a85 100644
--- a/storage/filesystem/internal/dotgit/dotgit_test.go
+++ b/storage/filesystem/internal/dotgit/dotgit_test.go
@@ -130,6 +130,61 @@ func (s *SuiteDotGit) TestConfig(c *C) {
 	c.Assert(filepath.Base(file.Filename()), Equals, "config")
 }
 
+func (s *SuiteDotGit) TestConfigWriteAndConfig(c *C) {
+	tmp, err := ioutil.TempDir("", "dot-git")
+	c.Assert(err, IsNil)
+	defer os.RemoveAll(tmp)
+
+	fs := osfs.New(tmp)
+	dir := New(fs)
+
+	f, err := dir.ConfigWriter()
+	c.Assert(err, IsNil)
+
+	_, err = f.Write([]byte("foo"))
+	c.Assert(err, IsNil)
+
+	f, err = dir.Config()
+	c.Assert(err, IsNil)
+
+	cnt, err := ioutil.ReadAll(f)
+	c.Assert(err, IsNil)
+
+	c.Assert(string(cnt), Equals, "foo")
+}
+
+func (s *SuiteDotGit) TestShallow(c *C) {
+	fs := fixtures.Basic().ByTag(".git").One().DotGit()
+	dir := New(fs)
+
+	file, err := dir.Shallow()
+	c.Assert(err, IsNil)
+	c.Assert(file, IsNil)
+}
+
+func (s *SuiteDotGit) TestShallowWriteAndShallow(c *C) {
+	tmp, err := ioutil.TempDir("", "dot-git")
+	c.Assert(err, IsNil)
+	defer os.RemoveAll(tmp)
+
+	fs := osfs.New(tmp)
+	dir := New(fs)
+
+	f, err := dir.ShallowWriter()
+	c.Assert(err, IsNil)
+
+	_, err = f.Write([]byte("foo"))
+	c.Assert(err, IsNil)
+
+	f, err = dir.Shallow()
+	c.Assert(err, IsNil)
+
+	cnt, err := ioutil.ReadAll(f)
+	c.Assert(err, IsNil)
+
+	c.Assert(string(cnt), Equals, "foo")
+}
+
 func findReference(refs []*plumbing.Reference, name string) *plumbing.Reference {
 	n := plumbing.ReferenceName(name)
 	for _, ref := range refs {
@@ -222,6 +277,18 @@ func (s *SuiteDotGit) TestObjects(c *C) {
 	c.Assert(hashes[2].String(), Equals, "03db8e1fbe133a480f2867aac478fd866686d69e")
 }
 
+func (s *SuiteDotGit) TestObjectsNoFolder(c *C) {
+	tmp, err := ioutil.TempDir("", "dot-git")
+	c.Assert(err, IsNil)
+	defer os.RemoveAll(tmp)
+
+	fs := osfs.New(tmp)
+	dir := New(fs)
+	hash, err := dir.Objects()
+	c.Assert(err, IsNil)
+	c.Assert(hash, HasLen, 0)
+}
+
 func (s *SuiteDotGit) TestObject(c *C) {
 	fs := fixtures.ByTag(".git").ByTag("unpacked").One().DotGit()
 	dir := New(fs)