feat(dir2config): defaults

vendor/gopkg.in/src-d/go-git.v4/plumbing/storer/reference.go

@@ -0,0 +1,240 @@
+package storer
+
+import (
+	"errors"
+	"io"
+
+	"gopkg.in/src-d/go-git.v4/plumbing"
+)
+
+const MaxResolveRecursion = 1024
+
+// ErrMaxResolveRecursion is returned by ResolveReference is MaxResolveRecursion
+// is exceeded
+var ErrMaxResolveRecursion = errors.New("max. recursion level reached")
+
+// ReferenceStorer is a generic storage of references.
+type ReferenceStorer interface {
+	SetReference(*plumbing.Reference) error
+	// CheckAndSetReference sets the reference `new`, but if `old` is
+	// not `nil`, it first checks that the current stored value for
+	// `old.Name()` matches the given reference value in `old`.  If
+	// not, it returns an error and doesn't update `new`.
+	CheckAndSetReference(new, old *plumbing.Reference) error
+	Reference(plumbing.ReferenceName) (*plumbing.Reference, error)
+	IterReferences() (ReferenceIter, error)
+	RemoveReference(plumbing.ReferenceName) error
+	CountLooseRefs() (int, error)
+	PackRefs() error
+}
+
+// ReferenceIter is a generic closable interface for iterating over references.
+type ReferenceIter interface {
+	Next() (*plumbing.Reference, error)
+	ForEach(func(*plumbing.Reference) error) error
+	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.
+//
+// The ReferenceSliceIter must be closed with a call to Close() when it is no
+// longer needed.
+type ReferenceSliceIter struct {
+	series []*plumbing.Reference
+	pos    int
+}
+
+// NewReferenceSliceIter returns a reference iterator for the given slice of
+// objects.
+func NewReferenceSliceIter(series []*plumbing.Reference) ReferenceIter {
+	return &ReferenceSliceIter{
+		series: series,
+	}
+}
+
+// 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 *ReferenceSliceIter) Next() (*plumbing.Reference, error) {
+	if iter.pos >= len(iter.series) {
+		return nil, io.EOF
+	}
+
+	obj := iter.series[iter.pos]
+	iter.pos++
+	return obj, nil
+}
+
+// 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 stop but no error is returned. The iterator is closed.
+func (iter *ReferenceSliceIter) ForEach(cb func(*plumbing.Reference) error) error {
+	return forEachReferenceIter(iter, cb)
+}
+
+type bareReferenceIterator interface {
+	Next() (*plumbing.Reference, error)
+	Close()
+}
+
+func forEachReferenceIter(iter bareReferenceIterator, cb func(*plumbing.Reference) error) error {
+	defer iter.Close()
+	for {
+		obj, err := iter.Next()
+		if err != nil {
+			if err == io.EOF {
+				return nil
+			}
+
+			return err
+		}
+
+		if err := cb(obj); err != nil {
+			if err == ErrStop {
+				return nil
+			}
+
+			return err
+		}
+	}
+}
+
+// Close releases any resources used by the iterator.
+func (iter *ReferenceSliceIter) Close() {
+	iter.pos = len(iter.series)
+}
+
+// MultiReferenceIter implements ReferenceIter. It iterates over several
+// ReferenceIter,
+//
+// The MultiReferenceIter must be closed with a call to Close() when it is no
+// longer needed.
+type MultiReferenceIter struct {
+	iters []ReferenceIter
+}
+
+// NewMultiReferenceIter returns an reference iterator for the given slice of
+// EncodedObjectIters.
+func NewMultiReferenceIter(iters []ReferenceIter) ReferenceIter {
+	return &MultiReferenceIter{iters: iters}
+}
+
+// Next returns the next reference from the iterator, if one iterator reach
+// io.EOF is removed and the next one is used.
+func (iter *MultiReferenceIter) Next() (*plumbing.Reference, error) {
+	if len(iter.iters) == 0 {
+		return nil, io.EOF
+	}
+
+	obj, err := iter.iters[0].Next()
+	if err == io.EOF {
+		iter.iters[0].Close()
+		iter.iters = iter.iters[1:]
+		return iter.Next()
+	}
+
+	return obj, err
+}
+
+// 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 stop but no error is returned. The iterator is closed.
+func (iter *MultiReferenceIter) ForEach(cb func(*plumbing.Reference) error) error {
+	return forEachReferenceIter(iter, cb)
+}
+
+// Close releases any resources used by the iterator.
+func (iter *MultiReferenceIter) Close() {
+	for _, i := range iter.iters {
+		i.Close()
+	}
+}
+
+// ResolveReference resolves a SymbolicReference to a HashReference.
+func ResolveReference(s ReferenceStorer, n plumbing.ReferenceName) (*plumbing.Reference, error) {
+	r, err := s.Reference(n)
+	if err != nil || r == nil {
+		return r, err
+	}
+	return resolveReference(s, r, 0)
+}
+
+func resolveReference(s ReferenceStorer, r *plumbing.Reference, recursion int) (*plumbing.Reference, error) {
+	if r.Type() != plumbing.SymbolicReference {
+		return r, nil
+	}
+
+	if recursion > MaxResolveRecursion {
+		return nil, ErrMaxResolveRecursion
+	}
+
+	t, err := s.Reference(r.Target())
+	if err != nil {
+		return nil, err
+	}
+
+	recursion++
+	return resolveReference(s, t, recursion)
+}