1 files changed, 219 insertions, 0 deletions
diff --git a/plumbing/client/common/common.go b/plumbing/client/common/common.go
new file mode 100644
index 0000000..97f78c4
--- /dev/null
+++ b/plumbing/client/common/common.go
@@ -0,0 +1,219 @@
+// Package common contains interfaces and non-specific protocol entities
+package common
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"net/url"
+	"regexp"
+	"strings"
+
+	"gopkg.in/src-d/go-git.v4/plumbing"
+	"gopkg.in/src-d/go-git.v4/plumbing/format/packp"
+	"gopkg.in/src-d/go-git.v4/plumbing/format/packp/advrefs"
+	"gopkg.in/src-d/go-git.v4/plumbing/format/packp/pktline"
+	"gopkg.in/src-d/go-git.v4/plumbing/storer"
+	"gopkg.in/src-d/go-git.v4/storage/memory"
+)
+
+var (
+	ErrRepositoryNotFound    = errors.New("repository not found")
+	ErrAuthorizationRequired = errors.New("authorization required")
+	ErrEmptyGitUploadPack    = errors.New("empty git-upload-pack given")
+	ErrInvalidAuthMethod     = errors.New("invalid auth method")
+)
+
+const GitUploadPackServiceName = "git-upload-pack"
+
+type GitUploadPackService interface {
+	Connect() error
+	SetAuth(AuthMethod) error
+	Info() (*GitUploadPackInfo, error)
+	Fetch(*GitUploadPackRequest) (io.ReadCloser, error)
+	Disconnect() error
+}
+
+type AuthMethod interface {
+	Name() string
+	String() string
+}
+
+type Endpoint url.URL
+
+var (
+	isSchemeRegExp   = regexp.MustCompile("^[^:]+://")
+	scpLikeUrlRegExp = regexp.MustCompile("^(?P<user>[^@]+@)?(?P<host>[^:]+):/?(?P<path>.+)$")
+)
+
+func NewEndpoint(endpoint string) (Endpoint, error) {
+	endpoint = transformSCPLikeIfNeeded(endpoint)
+
+	u, err := url.Parse(endpoint)
+	if err != nil {
+		return Endpoint{}, plumbing.NewPermanentError(err)
+	}
+
+	if !u.IsAbs() {
+		return Endpoint{}, plumbing.NewPermanentError(fmt.Errorf(
+			"invalid endpoint: %s", endpoint,
+		))
+	}
+
+	return Endpoint(*u), nil
+}
+
+func transformSCPLikeIfNeeded(endpoint string) string {
+	if !isSchemeRegExp.MatchString(endpoint) && scpLikeUrlRegExp.MatchString(endpoint) {
+		m := scpLikeUrlRegExp.FindStringSubmatch(endpoint)
+		return fmt.Sprintf("ssh://%s%s/%s", m[1], m[2], m[3])
+	}
+
+	return endpoint
+}
+
+func (e *Endpoint) String() string {
+	u := url.URL(*e)
+	return u.String()
+}
+
+type GitUploadPackInfo struct {
+	Capabilities *packp.Capabilities
+	Refs         memory.ReferenceStorage
+}
+
+func NewGitUploadPackInfo() *GitUploadPackInfo {
+	return &GitUploadPackInfo{
+		Capabilities: packp.NewCapabilities(),
+		Refs:         make(memory.ReferenceStorage, 0),
+	}
+}
+
+func (i *GitUploadPackInfo) Decode(r io.Reader) error {
+	d := advrefs.NewDecoder(r)
+	ar := advrefs.New()
+	if err := d.Decode(ar); err != nil {
+		if err == advrefs.ErrEmpty {
+			return plumbing.NewPermanentError(err)
+		}
+		return plumbing.NewUnexpectedError(err)
+	}
+
+	i.Capabilities = ar.Capabilities
+
+	if err := i.addRefs(ar); err != nil {
+		return plumbing.NewUnexpectedError(err)
+	}
+
+	return nil
+}
+
+func (i *GitUploadPackInfo) addRefs(ar *advrefs.AdvRefs) error {
+	for name, hash := range ar.References {
+		ref := plumbing.NewReferenceFromStrings(name, hash.String())
+		i.Refs.SetReference(ref)
+	}
+
+	return i.addSymbolicRefs(ar)
+}
+
+func (i *GitUploadPackInfo) addSymbolicRefs(ar *advrefs.AdvRefs) error {
+	if !hasSymrefs(ar) {
+		return nil
+	}
+
+	for _, symref := range ar.Capabilities.Get("symref").Values {
+		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)
+		i.Refs.SetReference(ref)
+	}
+
+	return nil
+}
+
+func hasSymrefs(ar *advrefs.AdvRefs) bool {
+	return ar.Capabilities.Supports("symref")
+}
+
+func (i *GitUploadPackInfo) Head() *plumbing.Reference {
+	ref, _ := storer.ResolveReference(i.Refs, plumbing.HEAD)
+	return ref
+}
+
+func (i *GitUploadPackInfo) String() string {
+	return string(i.Bytes())
+}
+
+func (i *GitUploadPackInfo) Bytes() []byte {
+	var buf bytes.Buffer
+	e := pktline.NewEncoder(&buf)
+
+	_ = e.EncodeString("# service=git-upload-pack\n")
+
+	// inserting a flush-pkt here violates the protocol spec, but some
+	// servers do it, like Github.com
+	e.Flush()
+
+	_ = e.Encodef("%s HEAD\x00%s\n", i.Head().Hash(), i.Capabilities.String())
+
+	for _, ref := range i.Refs {
+		if ref.Type() != plumbing.HashReference {
+			continue
+		}
+
+		_ = e.Encodef("%s %s\n", ref.Hash(), ref.Name())
+	}
+
+	e.Flush()
+
+	return buf.Bytes()
+}
+
+type GitUploadPackRequest struct {
+	Wants []plumbing.Hash
+	Haves []plumbing.Hash
+	Depth int
+}
+
+func (r *GitUploadPackRequest) Want(h ...plumbing.Hash) {
+	r.Wants = append(r.Wants, h...)
+}
+
+func (r *GitUploadPackRequest) Have(h ...plumbing.Hash) {
+	r.Haves = append(r.Haves, h...)
+}
+
+func (r *GitUploadPackRequest) String() string {
+	b, _ := ioutil.ReadAll(r.Reader())
+	return string(b)
+}
+
+func (r *GitUploadPackRequest) Reader() *strings.Reader {
+	var buf bytes.Buffer
+	e := pktline.NewEncoder(&buf)
+
+	for _, want := range r.Wants {
+		_ = e.Encodef("want %s\n", want)
+	}
+
+	for _, have := range r.Haves {
+		_ = e.Encodef("have %s\n", have)
+	}
+
+	if r.Depth != 0 {
+		_ = e.Encodef("deepen %d\n", r.Depth)
+	}
+
+	_ = e.Flush()
+	_ = e.EncodeString("done\n")
+
+	return strings.NewReader(buf.String())
+}