2 files changed, 161 insertions, 1 deletions
diff --git a/plumbing/storer/reference.go b/plumbing/storer/reference.go
index d821ecf..32265fe 100644
--- a/plumbing/storer/reference.go
+++ b/plumbing/storer/reference.go
@@ -28,6 +28,67 @@ type ReferenceIter interface {
 	Close()
 }
 
+type ReferenceFilteredIter struct {
+	ff   func(r *plumbing.Reference) bool
+	iter ReferenceIter
+}
+
+// NewReferenceFilteredIter returns a reference iterator for the given reference
+// Iterator. This iterator will iterate only references that accomplish the
+// provided function.
+func NewReferenceFilteredIter(
+	ff func(r *plumbing.Reference) bool, iter ReferenceIter) ReferenceIter {
+	return &ReferenceFilteredIter{ff, iter}
+}
+
+// Next returns the next reference from the iterator. If the iterator has reached
+// the end it will return io.EOF as an error.
+func (iter *ReferenceFilteredIter) Next() (*plumbing.Reference, error) {
+	for {
+		r, err := iter.iter.Next()
+		if err != nil {
+			return nil, err
+		}
+
+		if iter.ff(r) {
+			return r, nil
+		}
+
+		continue
+	}
+}
+
+// ForEach call the cb function for each reference contained on this iter until
+// an error happens or the end of the iter is reached. If ErrStop is sent
+// the iteration is stopped but no error is returned. The iterator is closed.
+func (iter *ReferenceFilteredIter) ForEach(cb func(*plumbing.Reference) error) error {
+	defer iter.Close()
+	for {
+		r, err := iter.Next()
+		if err == io.EOF {
+			break
+		}
+		if err != nil {
+			return err
+		}
+
+		if err := cb(r); err != nil {
+			if err == ErrStop {
+				break
+			}
+
+			return err
+		}
+	}
+
+	return nil
+}
+
+// Close releases any resources used by the iterator.
+func (iter *ReferenceFilteredIter) Close() {
+	iter.iter.Close()
+}
+
 // ReferenceSliceIter implements ReferenceIter. It iterates over a series of
 // references stored in a slice and yields each one in turn when Next() is
 // called.
@@ -41,7 +102,7 @@ type ReferenceSliceIter struct {
 
 // NewReferenceSliceIter returns a reference iterator for the given slice of
 // objects.
-func NewReferenceSliceIter(series []*plumbing.Reference) *ReferenceSliceIter {
+func NewReferenceSliceIter(series []*plumbing.Reference) ReferenceIter {
 	return &ReferenceSliceIter{
 		series: series,
 	}
diff --git a/plumbing/storer/reference_test.go b/plumbing/storer/reference_test.go
index ff7bd68..a6e301b 100644
--- a/plumbing/storer/reference_test.go
+++ b/plumbing/storer/reference_test.go
@@ -89,3 +89,102 @@ func (s *ReferenceSuite) TestReferenceSliceIterForEachStop(c *C) {
 
 	c.Assert(count, Equals, 1)
 }
+
+func (s *ReferenceSuite) TestReferenceFilteredIterNext(c *C) {
+	slice := []*plumbing.Reference{
+		plumbing.NewReferenceFromStrings("foo", "foo"),
+		plumbing.NewReferenceFromStrings("bar", "bar"),
+	}
+
+	i := NewReferenceFilteredIter(func(r *plumbing.Reference) bool {
+		if r.Name() == "bar" {
+			return true
+		}
+
+		return false
+	}, NewReferenceSliceIter(slice))
+	foo, err := i.Next()
+	c.Assert(err, IsNil)
+	c.Assert(foo == slice[0], Equals, false)
+	c.Assert(foo == slice[1], Equals, true)
+
+	empty, err := i.Next()
+	c.Assert(err, Equals, io.EOF)
+	c.Assert(empty, IsNil)
+}
+
+func (s *ReferenceSuite) TestReferenceFilteredIterForEach(c *C) {
+	slice := []*plumbing.Reference{
+		plumbing.NewReferenceFromStrings("foo", "foo"),
+		plumbing.NewReferenceFromStrings("bar", "bar"),
+	}
+
+	i := NewReferenceFilteredIter(func(r *plumbing.Reference) bool {
+		if r.Name() == "bar" {
+			return true
+		}
+
+		return false
+	}, NewReferenceSliceIter(slice))
+	var count int
+	i.ForEach(func(r *plumbing.Reference) error {
+		c.Assert(r == slice[1], Equals, true)
+		count++
+		return nil
+	})
+
+	c.Assert(count, Equals, 1)
+}
+
+func (s *ReferenceSuite) TestReferenceFilteredIterError(c *C) {
+	slice := []*plumbing.Reference{
+		plumbing.NewReferenceFromStrings("foo", "foo"),
+		plumbing.NewReferenceFromStrings("bar", "bar"),
+	}
+
+	i := NewReferenceFilteredIter(func(r *plumbing.Reference) bool {
+		if r.Name() == "bar" {
+			return true
+		}
+
+		return false
+	}, NewReferenceSliceIter(slice))
+	var count int
+	exampleErr := errors.New("SOME ERROR")
+	err := i.ForEach(func(r *plumbing.Reference) error {
+		c.Assert(r == slice[1], Equals, true)
+		count++
+		if count == 1 {
+			return exampleErr
+		}
+
+		return nil
+	})
+
+	c.Assert(err, Equals, exampleErr)
+	c.Assert(count, Equals, 1)
+}
+
+func (s *ReferenceSuite) TestReferenceFilteredIterForEachStop(c *C) {
+	slice := []*plumbing.Reference{
+		plumbing.NewReferenceFromStrings("foo", "foo"),
+		plumbing.NewReferenceFromStrings("bar", "bar"),
+	}
+
+	i := NewReferenceFilteredIter(func(r *plumbing.Reference) bool {
+		if r.Name() == "bar" {
+			return true
+		}
+
+		return false
+	}, NewReferenceSliceIter(slice))
+
+	var count int
+	i.ForEach(func(r *plumbing.Reference) error {
+		c.Assert(r == slice[1], Equals, true)
+		count++
+		return ErrStop
+	})
+
+	c.Assert(count, Equals, 1)
+}