Refactor to use core.ObjectReader and core.ObjectWriter

* New function signatures provide the necessary interface to stream data from disk when using filesystem-based storage in the future
* New function signatures provide proper error handling
* ObjectReader and ObjectWriter interfaces added to avoid future refactoring, currently are type aliases for io.ReadCloser and io.WriteCloser respectively
* Object.Reader now returns (ObjectReader, error)
* Object.Writer now returns (ObjectWriter, error)
* File.Contents now returns (string, error)
* File.Lines now returns ([]string, error)
* Blob.Reader now returns (core.ObjectReader, error)
* Added internal close helper function for deferred calls to Close that need to check the return value

1 files changed, 9 insertions, 2 deletions

diff --git a/commit.go b/commit.go
index 492a928..4b7d918 100644
--- a/commit.go
+++ b/commit.go
@@ -50,13 +50,20 @@ func (c *Commit) File(path string) (file *File, err error) {
 }
 
 // Decode transform an core.Object into a Blob struct
-func (c *Commit) Decode(o core.Object) error {
+func (c *Commit) Decode(o core.Object) (err error) {
 	if o.Type() != core.CommitObject {
 		return ErrUnsupportedObject
 	}
 
 	c.Hash = o.Hash()
-	r := bufio.NewReader(o.Reader())
+
+	reader, err := o.Reader()
+	if err != nil {
+		return err
+	}
+	defer close(reader, &err)
+
+	r := bufio.NewReader(reader)
 
 	var message bool
 	for {