repository: partial impl of a go-git backed Repo

1 files changed, 378 insertions, 0 deletions

diff --git a/repository/gogit.go b/repository/gogit.go
new file mode 100644
index 00000000..71a7e6d0
--- /dev/null
+++ b/repository/gogit.go
@@ -0,0 +1,378 @@
+package repository
+
+import (
+	"bytes"
+	"fmt"
+	"io/ioutil"
+	"os"
+	stdpath "path"
+	"path/filepath"
+	"sync"
+
+	gogit "github.com/go-git/go-git/v5"
+	"github.com/go-git/go-git/v5/config"
+	"github.com/go-git/go-git/v5/plumbing"
+
+	"github.com/MichaelMure/git-bug/util/lamport"
+)
+
+var _ ClockedRepo = &GoGitRepo{}
+
+type GoGitRepo struct {
+	r    *gogit.Repository
+	path string
+
+	clocksMutex sync.Mutex
+	clocks      map[string]lamport.Clock
+}
+
+func NewGoGitRepo(path string, clockLoaders []ClockLoader) (*GoGitRepo, error) {
+	path, err := detectGitPath(path)
+	if err != nil {
+		return nil, err
+	}
+
+	r, err := gogit.PlainOpen(path)
+	if err != nil {
+		return nil, err
+	}
+
+	repo := &GoGitRepo{
+		r:      r,
+		path:   path,
+		clocks: make(map[string]lamport.Clock),
+	}
+
+	for _, loader := range clockLoaders {
+		allExist := true
+		for _, name := range loader.Clocks {
+			if _, err := repo.getClock(name); err != nil {
+				allExist = false
+			}
+		}
+
+		if !allExist {
+			err = loader.Witnesser(repo)
+			if err != nil {
+				return nil, err
+			}
+		}
+	}
+
+	return repo, nil
+}
+
+func detectGitPath(path string) (string, error) {
+	// normalize the path
+	path, err := filepath.Abs(path)
+	if err != nil {
+		return "", err
+	}
+
+	for {
+		fi, err := os.Stat(stdpath.Join(path, ".git"))
+		if err == nil {
+			if !fi.IsDir() {
+				return "", fmt.Errorf(".git exist but is not a directory")
+			}
+			return stdpath.Join(path, ".git"), nil
+		}
+		if !os.IsNotExist(err) {
+			// unknown error
+			return "", err
+		}
+
+		// detect bare repo
+		ok, err := isGitDir(path)
+		if err != nil {
+			return "", err
+		}
+		if ok {
+			return path, nil
+		}
+
+		if parent := filepath.Dir(path); parent == path {
+			return "", fmt.Errorf(".git not found")
+		} else {
+			path = parent
+		}
+	}
+}
+
+func isGitDir(path string) (bool, error) {
+	markers := []string{"HEAD", "objects", "refs"}
+
+	for _, marker := range markers {
+		_, err := os.Stat(stdpath.Join(path, marker))
+		if err == nil {
+			continue
+		}
+		if !os.IsNotExist(err) {
+			// unknown error
+			return false, err
+		} else {
+			return false, nil
+		}
+	}
+
+	return true, nil
+}
+
+// InitGoGitRepo create a new empty git repo at the given path
+func InitGoGitRepo(path string) (*GoGitRepo, error) {
+	r, err := gogit.PlainInit(path, false)
+	if err != nil {
+		return nil, err
+	}
+
+	return &GoGitRepo{
+		r:      r,
+		path:   path + "/.git",
+		clocks: make(map[string]lamport.Clock),
+	}, nil
+}
+
+// InitBareGoGitRepo create a new --bare empty git repo at the given path
+func InitBareGoGitRepo(path string) (*GoGitRepo, error) {
+	r, err := gogit.PlainInit(path, true)
+	if err != nil {
+		return nil, err
+	}
+
+	return &GoGitRepo{
+		r:      r,
+		path:   path,
+		clocks: make(map[string]lamport.Clock),
+	}, nil
+}
+
+func (repo *GoGitRepo) LocalConfig() Config {
+	return newGoGitConfig(repo.r)
+}
+
+func (repo *GoGitRepo) GlobalConfig() Config {
+	panic("go-git doesn't support writing global config")
+}
+
+// GetPath returns the path to the repo.
+func (repo *GoGitRepo) GetPath() string {
+	return repo.path
+}
+
+// GetUserName returns the name the the user has used to configure git
+func (repo *GoGitRepo) GetUserName() (string, error) {
+	cfg, err := repo.r.Config()
+	if err != nil {
+		return "", err
+	}
+
+	return cfg.User.Name, nil
+}
+
+// GetUserEmail returns the email address that the user has used to configure git.
+func (repo *GoGitRepo) GetUserEmail() (string, error) {
+	cfg, err := repo.r.Config()
+	if err != nil {
+		return "", err
+	}
+
+	return cfg.User.Email, nil
+}
+
+// GetCoreEditor returns the name of the editor that the user has used to configure git.
+func (repo *GoGitRepo) GetCoreEditor() (string, error) {
+
+	panic("implement me")
+}
+
+// GetRemotes returns the configured remotes repositories.
+func (repo *GoGitRepo) GetRemotes() (map[string]string, error) {
+	cfg, err := repo.r.Config()
+	if err != nil {
+		return nil, err
+	}
+
+	result := make(map[string]string, len(cfg.Remotes))
+	for name, remote := range cfg.Remotes {
+		if len(remote.URLs) > 0 {
+			result[name] = remote.URLs[0]
+		}
+	}
+
+	return result, nil
+}
+
+// FetchRefs fetch git refs from a remote
+func (repo *GoGitRepo) FetchRefs(remote string, refSpec string) (string, error) {
+	buf := bytes.NewBuffer(nil)
+
+	err := repo.r.Fetch(&gogit.FetchOptions{
+		RemoteName: remote,
+		RefSpecs:   []config.RefSpec{config.RefSpec(refSpec)},
+		Progress:   buf,
+	})
+	if err != nil {
+		return "", err
+	}
+
+	return buf.String(), nil
+}
+
+// PushRefs push git refs to a remote
+func (repo *GoGitRepo) PushRefs(remote string, refSpec string) (string, error) {
+	buf := bytes.NewBuffer(nil)
+
+	err := repo.r.Push(&gogit.PushOptions{
+		RemoteName: remote,
+		RefSpecs:   []config.RefSpec{config.RefSpec(refSpec)},
+		Progress:   buf,
+	})
+	if err != nil {
+		return "", err
+	}
+
+	return buf.String(), nil
+}
+
+// StoreData will store arbitrary data and return the corresponding hash
+func (repo *GoGitRepo) StoreData(data []byte) (Hash, error) {
+	obj := repo.r.Storer.NewEncodedObject()
+	obj.SetType(plumbing.BlobObject)
+
+	w, err := obj.Writer()
+	if err != nil {
+		return "", err
+	}
+
+	_, err = w.Write(data)
+	if err != nil {
+		return "", err
+	}
+
+	h, err := repo.r.Storer.SetEncodedObject(obj)
+	if err != nil {
+		return "", err
+	}
+
+	return Hash(h.String()), nil
+}
+
+// ReadData will attempt to read arbitrary data from the given hash
+func (repo *GoGitRepo) ReadData(hash Hash) ([]byte, error) {
+	obj, err := repo.r.BlobObject(plumbing.NewHash(hash.String()))
+	if err != nil {
+		return nil, err
+	}
+
+	r, err := obj.Reader()
+	if err != nil {
+		return nil, err
+	}
+
+	return ioutil.ReadAll(r)
+}
+
+func (repo *GoGitRepo) StoreTree(mapping []TreeEntry) (Hash, error) {
+	panic("implement me")
+}
+
+func (repo *GoGitRepo) ReadTree(hash Hash) ([]TreeEntry, error) {
+	panic("implement me")
+}
+
+func (repo *GoGitRepo) StoreCommit(treeHash Hash) (Hash, error) {
+	panic("implement me")
+}
+
+func (repo *GoGitRepo) StoreCommitWithParent(treeHash Hash, parent Hash) (Hash, error) {
+	panic("implement me")
+}
+
+func (repo *GoGitRepo) GetTreeHash(commit Hash) (Hash, error) {
+	panic("implement me")
+}
+
+func (repo *GoGitRepo) FindCommonAncestor(commit1 Hash, commit2 Hash) (Hash, error) {
+	panic("implement me")
+}
+
+func (repo *GoGitRepo) UpdateRef(ref string, hash Hash) error {
+	panic("implement me")
+}
+
+func (repo *GoGitRepo) RemoveRef(ref string) error {
+	panic("implement me")
+}
+
+func (repo *GoGitRepo) ListRefs(refspec string) ([]string, error) {
+	panic("implement me")
+}
+
+func (repo *GoGitRepo) RefExist(ref string) (bool, error) {
+	panic("implement me")
+}
+
+func (repo *GoGitRepo) CopyRef(source string, dest string) error {
+	panic("implement me")
+}
+
+func (repo *GoGitRepo) ListCommits(ref string) ([]Hash, error) {
+	panic("implement me")
+}
+
+// GetOrCreateClock return a Lamport clock stored in the Repo.
+// If the clock doesn't exist, it's created.
+func (repo *GoGitRepo) GetOrCreateClock(name string) (lamport.Clock, error) {
+	c, err := repo.getClock(name)
+	if err == nil {
+		return c, nil
+	}
+	if err != ErrClockNotExist {
+		return nil, err
+	}
+
+	repo.clocksMutex.Lock()
+	defer repo.clocksMutex.Unlock()
+
+	p := clockPath + name + "-clock"
+
+	c, err = lamport.NewPersistedClock(p)
+	if err != nil {
+		return nil, err
+	}
+
+	repo.clocks[name] = c
+	return c, nil
+}
+
+func (repo *GoGitRepo) getClock(name string) (lamport.Clock, error) {
+	repo.clocksMutex.Lock()
+	defer repo.clocksMutex.Unlock()
+
+	if c, ok := repo.clocks[name]; ok {
+		return c, nil
+	}
+
+	p := clockPath + name + "-clock"
+
+	c, err := lamport.LoadPersistedClock(p)
+	if err == nil {
+		repo.clocks[name] = c
+		return c, nil
+	}
+	if err == lamport.ErrClockNotExist {
+		return nil, ErrClockNotExist
+	}
+	return nil, err
+}
+
+// AddRemote add a new remote to the repository
+// Not in the interface because it's only used for testing
+func (repo *GoGitRepo) AddRemote(name string, url string) error {
+	_, err := repo.r.CreateRemote(&config.RemoteConfig{
+		Name: name,
+		URLs: []string{url},
+	})
+
+	return err
+}