feat(dir2config): defaults

vendor/gopkg.in/src-d/go-git.v4/plumbing/protocol/packp/advrefs.go

@@ -0,0 +1,203 @@
+package packp
+
+import (
+	"fmt"
+	"sort"
+	"strings"
+
+	"gopkg.in/src-d/go-git.v4/plumbing"
+	"gopkg.in/src-d/go-git.v4/plumbing/protocol/packp/capability"
+	"gopkg.in/src-d/go-git.v4/plumbing/storer"
+	"gopkg.in/src-d/go-git.v4/storage/memory"
+)
+
+// AdvRefs values represent the information transmitted on an
+// advertised-refs message.  Values from this type are not zero-value
+// safe, use the New function instead.
+type AdvRefs struct {
+	// Prefix stores prefix payloads.
+	//
+	// When using this message over (smart) HTTP, you have to add a pktline
+	// before the whole thing with the following payload:
+	//
+	// '# service=$servicename" LF
+	//
+	// Moreover, some (all) git HTTP smart servers will send a flush-pkt
+	// just after the first pkt-line.
+	//
+	// To accommodate both situations, the Prefix field allow you to store
+	// any data you want to send before the actual pktlines.  It will also
+	// be filled up with whatever is found on the line.
+	Prefix [][]byte
+	// Head stores the resolved HEAD reference if present.
+	// This can be present with git-upload-pack, not with git-receive-pack.
+	Head *plumbing.Hash
+	// Capabilities are the capabilities.
+	Capabilities *capability.List
+	// References are the hash references.
+	References map[string]plumbing.Hash
+	// Peeled are the peeled hash references.
+	Peeled map[string]plumbing.Hash
+	// Shallows are the shallow object ids.
+	Shallows []plumbing.Hash
+}
+
+// NewAdvRefs returns a pointer to a new AdvRefs value, ready to be used.
+func NewAdvRefs() *AdvRefs {
+	return &AdvRefs{
+		Prefix:       [][]byte{},
+		Capabilities: capability.NewList(),
+		References:   make(map[string]plumbing.Hash),
+		Peeled:       make(map[string]plumbing.Hash),
+		Shallows:     []plumbing.Hash{},
+	}
+}
+
+func (a *AdvRefs) AddReference(r *plumbing.Reference) error {
+	switch r.Type() {
+	case plumbing.SymbolicReference:
+		v := fmt.Sprintf("%s:%s", r.Name().String(), r.Target().String())
+		a.Capabilities.Add(capability.SymRef, v)
+	case plumbing.HashReference:
+		a.References[r.Name().String()] = r.Hash()
+	default:
+		return plumbing.ErrInvalidType
+	}
+
+	return nil
+}
+
+func (a *AdvRefs) AllReferences() (memory.ReferenceStorage, error) {
+	s := memory.ReferenceStorage{}
+	if err := a.addRefs(s); err != nil {
+		return s, plumbing.NewUnexpectedError(err)
+	}
+
+	return s, nil
+}
+
+func (a *AdvRefs) addRefs(s storer.ReferenceStorer) error {
+	for name, hash := range a.References {
+		ref := plumbing.NewReferenceFromStrings(name, hash.String())
+		if err := s.SetReference(ref); err != nil {
+			return err
+		}
+	}
+
+	if a.supportSymrefs() {
+		return a.addSymbolicRefs(s)
+	}
+
+	return a.resolveHead(s)
+}
+
+// If the server does not support symrefs capability,
+// we need to guess the reference where HEAD is pointing to.
+//
+// Git versions prior to 1.8.4.3 has an special procedure to get
+// the reference where is pointing to HEAD:
+// - Check if a reference called master exists. If exists and it
+//	 has the same hash as HEAD hash, we can say that HEAD is pointing to master
+// - If master does not exists or does not have the same hash as HEAD,
+//   order references and check in that order if that reference has the same
+//   hash than HEAD. If yes, set HEAD pointing to that branch hash
+// - If no reference is found, throw an error
+func (a *AdvRefs) resolveHead(s storer.ReferenceStorer) error {
+	if a.Head == nil {
+		return nil
+	}
+
+	ref, err := s.Reference(plumbing.ReferenceName(plumbing.Master))
+
+	// check first if HEAD is pointing to master
+	if err == nil {
+		ok, err := a.createHeadIfCorrectReference(ref, s)
+		if err != nil {
+			return err
+		}
+
+		if ok {
+			return nil
+		}
+	}
+
+	if err != nil && err != plumbing.ErrReferenceNotFound {
+		return err
+	}
+
+	// From here we are trying to guess the branch that HEAD is pointing
+	refIter, err := s.IterReferences()
+	if err != nil {
+		return err
+	}
+
+	var refNames []string
+	err = refIter.ForEach(func(r *plumbing.Reference) error {
+		refNames = append(refNames, string(r.Name()))
+		return nil
+	})
+	if err != nil {
+		return err
+	}
+
+	sort.Strings(refNames)
+
+	var headSet bool
+	for _, refName := range refNames {
+		ref, err := s.Reference(plumbing.ReferenceName(refName))
+		if err != nil {
+			return err
+		}
+		ok, err := a.createHeadIfCorrectReference(ref, s)
+		if err != nil {
+			return err
+		}
+		if ok {
+			headSet = true
+			break
+		}
+	}
+
+	if !headSet {
+		return plumbing.ErrReferenceNotFound
+	}
+
+	return nil
+}
+
+func (a *AdvRefs) createHeadIfCorrectReference(
+	reference *plumbing.Reference,
+	s storer.ReferenceStorer) (bool, error) {
+	if reference.Hash() == *a.Head {
+		headRef := plumbing.NewSymbolicReference(plumbing.HEAD, reference.Name())
+		if err := s.SetReference(headRef); err != nil {
+			return false, err
+		}
+
+		return true, nil
+	}
+
+	return false, nil
+}
+
+func (a *AdvRefs) addSymbolicRefs(s storer.ReferenceStorer) error {
+	for _, symref := range a.Capabilities.Get(capability.SymRef) {
+		chunks := strings.Split(symref, ":")
+		if len(chunks) != 2 {
+			err := fmt.Errorf("bad number of `:` in symref value (%q)", symref)
+			return plumbing.NewUnexpectedError(err)
+		}
+		name := plumbing.ReferenceName(chunks[0])
+		target := plumbing.ReferenceName(chunks[1])
+		ref := plumbing.NewSymbolicReference(name, target)
+		if err := s.SetReference(ref); err != nil {
+			return nil
+		}
+	}
+
+	return nil
+}
+
+func (a *AdvRefs) supportSymrefs() bool {
+	return a.Capabilities.Supports(capability.SymRef)
+}