package packp import ( "fmt" "sort" "strings" "github.com/go-git/go-git/v5/plumbing" "github.com/go-git/go-git/v5/plumbing/protocol/packp/capability" "github.com/go-git/go-git/v5/plumbing/storer" "github.com/go-git/go-git/v5/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.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) }