plumbing: packfile, lazy object reads with DiskObjects

Signed-off-by: Miguel Molina <miguel@erizocosmi.co>

1 files changed, 64 insertions, 0 deletions

diff --git a/plumbing/format/packfile/disk_object.go b/plumbing/format/packfile/disk_object.go
new file mode 100644
index 0000000..d3e8520
--- /dev/null
+++ b/plumbing/format/packfile/disk_object.go
@@ -0,0 +1,64 @@
+package packfile
+
+import (
+	"io"
+
+	"gopkg.in/src-d/go-git.v4/plumbing"
+)
+
+// DiskObject is an object from the packfile on disk.
+type DiskObject struct {
+	hash     plumbing.Hash
+	h        *ObjectHeader
+	offset   int64
+	size     int64
+	typ      plumbing.ObjectType
+	packfile *Packfile
+}
+
+// NewDiskObject creates a new disk object.
+func NewDiskObject(
+	hash plumbing.Hash,
+	finalType plumbing.ObjectType,
+	offset int64,
+	contentSize int64,
+	packfile *Packfile,
+) *DiskObject {
+	return &DiskObject{
+		hash:     hash,
+		offset:   offset,
+		size:     contentSize,
+		typ:      finalType,
+		packfile: packfile,
+	}
+}
+
+// Reader implements the plumbing.EncodedObject interface.
+func (o *DiskObject) Reader() (io.ReadCloser, error) {
+	return o.packfile.getObjectContent(o.offset)
+}
+
+// SetSize implements the plumbing.EncodedObject interface. This method
+// is a noop.
+func (o *DiskObject) SetSize(int64) {}
+
+// SetType implements the plumbing.EncodedObject interface. This method is
+// a noop.
+func (o *DiskObject) SetType(plumbing.ObjectType) {}
+
+// Hash implements the plumbing.EncodedObject interface.
+func (o *DiskObject) Hash() plumbing.Hash { return o.hash }
+
+// Size implements the plumbing.EncodedObject interface.
+func (o *DiskObject) Size() int64 { return o.size }
+
+// Type implements the plumbing.EncodedObject interface.
+func (o *DiskObject) Type() plumbing.ObjectType {
+	return o.typ
+}
+
+// Writer implements the plumbing.EncodedObject interface. This method always
+// returns a nil writer.
+func (o *DiskObject) Writer() (io.WriteCloser, error) {
+	return nil, nil
+}