ref: 2da7bba85f89289dd545cf967fd27efa4235c36e
dir: /repository/repository.go/
// Package repository wires object and ref storage for one Git repository.
package repository
import (
"errors"
"fmt"
"os"
"codeberg.org/lindenii/furgit/config"
"codeberg.org/lindenii/furgit/objectid"
"codeberg.org/lindenii/furgit/objectstore"
objectchain "codeberg.org/lindenii/furgit/objectstore/chain"
objectloose "codeberg.org/lindenii/furgit/objectstore/loose"
objectpacked "codeberg.org/lindenii/furgit/objectstore/packed"
"codeberg.org/lindenii/furgit/refstore"
refchain "codeberg.org/lindenii/furgit/refstore/chain"
refloose "codeberg.org/lindenii/furgit/refstore/loose"
refpacked "codeberg.org/lindenii/furgit/refstore/packed"
reftable "codeberg.org/lindenii/furgit/refstore/reftable"
)
// Repository is a thin composition root for repository-local stores.
//
// Open expects a root for the Git directory itself:
// a bare repository root or a non-bare ".git" directory.
type Repository struct {
config *config.Config
algo objectid.Algorithm
objects objectstore.Store
objectsLooseForWritingOnly *objectloose.Store
refs refstore.Store
}
// Open opens a repository and wires object/ref stores from its on-disk format.
//
// Open borrows root during construction and does not close it.
func Open(root *os.Root) (repo *Repository, err error) {
repo = &Repository{}
defer func() {
if err != nil {
_ = repo.Close()
}
}()
cfg, err := parseRepositoryConfig(root)
if err != nil {
return nil, err
}
repo.config = cfg
algo, err := detectObjectAlgorithm(cfg)
if err != nil {
return nil, err
}
repo.algo = algo
objects, objectsLooseForWritingOnly, err := openObjectStore(root, algo)
if err != nil {
return nil, err
}
repo.objects = objects
repo.objectsLooseForWritingOnly = objectsLooseForWritingOnly
refs, err := openRefStore(root, algo)
if err != nil {
return nil, err
}
repo.refs = refs
return repo, nil
}
// Algorithm returns the repository object ID algorithm.
func (repo *Repository) Algorithm() objectid.Algorithm {
return repo.algo
}
// Config returns the parsed repository configuration snapshot.
//
// The returned pointer is owned by Repository. Callers should treat it as
// read-only.
func (repo *Repository) Config() *config.Config {
return repo.config
}
// Objects returns the configured object store.
func (repo *Repository) Objects() objectstore.Store {
return repo.objects
}
// Refs returns the configured ref store.
func (repo *Repository) Refs() refstore.Store {
return repo.refs
}
// Close closes owned stores and filesystem roots.
// The behavior of the repo after Close is undefined.
func (repo *Repository) Close() error {
var errs []error
if repo.refs != nil {
err := repo.refs.Close()
if err != nil {
errs = append(errs, err)
}
}
if repo.objects != nil {
err := repo.objects.Close()
if err != nil {
errs = append(errs, err)
}
}
if repo.objectsLooseForWritingOnly != nil {
err := repo.objectsLooseForWritingOnly.Close()
if err != nil {
errs = append(errs, err)
}
}
return errors.Join(errs...)
}
func parseRepositoryConfig(root *os.Root) (*config.Config, error) {
configFile, err := root.Open("config")
if err != nil {
return nil, fmt.Errorf("repository: open config: %w", err)
}
defer func() { _ = configFile.Close() }()
cfg, err := config.ParseConfig(configFile)
if err != nil {
return nil, fmt.Errorf("repository: parse config: %w", err)
}
return cfg, nil
}
func detectObjectAlgorithm(cfg *config.Config) (objectid.Algorithm, error) {
algoName := cfg.Lookup("extensions", "", "objectformat").Value
if algoName == "" {
algoName = objectid.AlgorithmSHA1.String()
}
algo, ok := objectid.ParseAlgorithm(algoName)
if !ok {
return objectid.AlgorithmUnknown, fmt.Errorf("repository: unsupported object format %q", algoName)
}
return algo, nil
}
func openObjectStore(root *os.Root, algo objectid.Algorithm) (objectstore.Store, *objectloose.Store, error) {
objectsRoot, err := root.OpenRoot("objects")
if err != nil {
return nil, nil, fmt.Errorf("repository: open objects: %w", err)
}
looseStore, err := objectloose.New(objectsRoot, algo)
if err != nil {
return nil, nil, err
}
backends := []objectstore.Store{looseStore}
packRoot, err := objectsRoot.OpenRoot("pack")
if err == nil {
var packedStore *objectpacked.Store
packedStore, err = objectpacked.New(packRoot, algo)
if err != nil {
_ = looseStore.Close()
return nil, nil, err
}
backends = append(backends, packedStore)
} else if !errors.Is(err, os.ErrNotExist) {
_ = looseStore.Close()
return nil, nil, fmt.Errorf("repository: open objects/pack: %w", err)
}
objectsChain := objectchain.New(backends...)
objectsRootForWriting, err := root.OpenRoot("objects")
if err != nil {
_ = objectsChain.Close()
return nil, nil, fmt.Errorf("repository: open objects for loose writing: %w", err)
}
objectsLooseForWritingOnly, err := objectloose.New(objectsRootForWriting, algo)
if err != nil {
_ = objectsRootForWriting.Close()
_ = objectsChain.Close()
return nil, nil, err
}
return objectsChain, objectsLooseForWritingOnly, nil
}
func openRefStore(root *os.Root, algo objectid.Algorithm) (out refstore.Store, err error) {
hasReftable, err := hasReftableStack(root)
if err != nil {
return nil, err
}
if hasReftable {
reftableRoot, err := root.OpenRoot("reftable")
if err != nil {
return nil, fmt.Errorf("repository: open reftable: %w", err)
}
reftableStore, err := reftable.New(reftableRoot, algo)
if err != nil {
_ = reftableRoot.Close()
return nil, err
}
return reftableStore, nil
}
looseRoot, err := root.OpenRoot(".")
if err != nil {
return nil, fmt.Errorf("repository: open root for loose refs: %w", err)
}
looseStore, err := refloose.New(looseRoot, algo)
if err != nil {
_ = looseRoot.Close()
return nil, err
}
backends := []refstore.Store{looseStore}
_, err = root.Stat("packed-refs")
if err == nil {
packedStore, packedErr := refpacked.New(root, algo)
if packedErr != nil {
_ = looseStore.Close()
return nil, packedErr
}
backends = append(backends, packedStore)
} else if !errors.Is(err, os.ErrNotExist) {
_ = looseStore.Close()
return nil, fmt.Errorf("repository: stat packed-refs: %w", err)
}
return refchain.New(backends...), nil
}
func hasReftableStack(root *os.Root) (bool, error) {
_, err := root.Stat("reftable/tables.list")
if err == nil {
return true, nil
}
if errors.Is(err, os.ErrNotExist) {
return false, nil
}
return false, fmt.Errorf("repository: stat reftable/tables.list: %w", err)
}