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package furgit
import (
"crypto/sha1"
"crypto/sha256"
"encoding/hex"
"fmt"
"os"
"path/filepath"
"sync"
"git.sr.ht/~runxiyu/furgit/config"
)
// Repository represents a Git repository.
//
// It is safe to access the same Repository from multiple goroutines
// without additional synchronization.
//
// Objects derived from a Repository must not be used after the Repository
// has been closed.
type Repository struct {
rootPath string
hashSize int
packIdxOnce sync.Once
packIdx []*packIndex
packIdxErr error
midxOnce sync.Once
midx *multiPackIndex
midxErr error
packFiles map[string]*packFile
packFilesMu sync.RWMutex
closeOnce sync.Once
}
// OpenRepository opens the repository at the provided path.
//
// The path is expected to be the actual repository directory, i.e.,
// the repository itself for bare repositories, or the .git
// subdirectory for non-bare repositories.
func OpenRepository(path string) (*Repository, error) {
fi, err := os.Stat(path)
if err != nil {
return nil, err
}
if !fi.IsDir() {
return nil, ErrInvalidObject
}
cfgPath := filepath.Join(path, "config")
f, err := os.Open(cfgPath)
if err != nil {
return nil, fmt.Errorf("furgit: unable to open config: %w", err)
}
defer func() {
_ = f.Close()
}()
cfg, err := config.ParseConfig(f)
if err != nil {
return nil, fmt.Errorf("furgit: failed to parse config: %w", err)
}
algo := cfg.Get("extensions", "", "objectformat")
if algo == "" {
algo = "sha1"
}
var hashSize int
switch algo {
case "sha1":
hashSize = sha1.Size
case "sha256":
hashSize = sha256.Size
default:
return nil, fmt.Errorf("furgit: unsupported hash algorithm %q", algo)
}
if _, ok := hashFuncs[hashSize]; !ok {
return nil, fmt.Errorf("furgit: hash algorithm %q is not supported by the hash functions provided by this build", algo)
}
return &Repository{
rootPath: path,
hashSize: hashSize,
packFiles: make(map[string]*packFile),
}, nil
}
// Close closes the repository, releasing any resources associated with it.
//
// It is safe to call Close multiple times; subsequent calls will have no
// effect.
//
// Close invalidates any objects derived from the Repository as it;
// using them may cause segmentation faults or other undefined behavior.
func (repo *Repository) Close() error {
var closeErr error
repo.closeOnce.Do(func() {
repo.packFilesMu.Lock()
for key, pf := range repo.packFiles {
err := pf.Close()
if err != nil && closeErr == nil {
closeErr = err
}
delete(repo.packFiles, key)
}
repo.packFilesMu.Unlock()
if len(repo.packIdx) > 0 {
for _, idx := range repo.packIdx {
err := idx.Close()
if err != nil && closeErr == nil {
closeErr = err
}
}
}
if repo.midx != nil {
err := repo.midx.Close()
if err != nil && closeErr == nil {
closeErr = err
}
}
})
return closeErr
}
// repoPath joins the root with a relative path.
func (repo *Repository) repoPath(rel string) string {
return filepath.Join(repo.rootPath, rel)
}
// ParseHash converts a hex string into a Hash, validating
// it matches the repository's hash size.
func (repo *Repository) ParseHash(s string) (Hash, error) {
var id Hash
if len(s)%2 != 0 {
return id, fmt.Errorf("furgit: invalid hash length %d, it has to be even at the very least", len(s))
}
expectedLen := repo.hashSize * 2
if len(s) != expectedLen {
return id, fmt.Errorf("furgit: hash length mismatch: got %d chars, expected %d for hash size %d", len(s), expectedLen, repo.hashSize)
}
data, err := hex.DecodeString(s)
if err != nil {
return id, fmt.Errorf("furgit: decode hash: %w", err)
}
copy(id.data[:], data)
id.size = len(s) / 2
return id, nil
}
// computeRawHash computes a hash from raw data using the repository's hash algorithm.
func (repo *Repository) computeRawHash(data []byte) Hash {
hashFunc := hashFuncs[repo.hashSize]
return hashFunc(data)
}
// verifyRawObject verifies a raw object against its expected hash.
func (repo *Repository) verifyRawObject(buf []byte, want Hash) bool { //nolint:unused
if want.size != repo.hashSize {
return false
}
return repo.computeRawHash(buf) == want
}
// verifyTypedObject verifies a typed object against its expected hash.
func (repo *Repository) verifyTypedObject(ty ObjectType, body []byte, want Hash) bool { //nolint:unused
if want.size != repo.hashSize {
return false
}
header, err := headerForType(ty, body)
if err != nil {
return false
}
raw := make([]byte, len(header)+len(body))
copy(raw, header)
copy(raw[len(header):], body)
return repo.computeRawHash(raw) == want
}
|
