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-rw-r--r--hash.go112
-rw-r--r--hash_test.go2
-rw-r--r--obj_tree.go6
-rw-r--r--pack_idx.go6
-rw-r--r--pack_pack.go4
-rw-r--r--refs.go4
-rw-r--r--repo.go23
-rw-r--r--repo_test.go2
8 files changed, 87 insertions, 72 deletions
diff --git a/hash.go b/hash.go
index df39ac30..cbaac821 100644
--- a/hash.go
+++ b/hash.go
@@ -6,59 +6,74 @@ import (
"encoding/hex"
)
-// maxHashSize MUST be equal to (or larger than) the size of the
-// largest hash supported in hashFuncs.
+// maxHashSize MUST be >= the largest supported algorithm size.
const maxHashSize = sha256.Size
// hashAlgorithm identifies the hash algorithm used for Git object IDs.
type hashAlgorithm uint8
-// hashFuncs maps hash algorithm to hash function.
-var hashFuncs = map[hashAlgorithm]hashFunc{
- hashAlgoSHA1: func(data []byte) Hash {
- sum := sha1.Sum(data)
- var h Hash
- copy(h.data[:], sum[:])
- h.algo = hashAlgoSHA1
- return h
- },
- hashAlgoSHA256: func(data []byte) Hash {
- sum := sha256.Sum256(data)
- var h Hash
- copy(h.data[:], sum[:])
- h.algo = hashAlgoSHA256
- return h
- },
-}
-
const (
hashAlgoUnknown hashAlgorithm = iota
hashAlgoSHA1
hashAlgoSHA256
)
-// size returns the hash size in bytes.
-func (algo hashAlgorithm) size() int {
- switch algo {
- case hashAlgoSHA1:
- return sha1.Size
- case hashAlgoSHA256:
- return sha256.Size
- default:
- return 0
- }
+type hashAlgorithmDetails struct {
+ name string
+ size int
+ sum func([]byte) Hash
+}
+
+var hashAlgorithmTable = [...]hashAlgorithmDetails{
+ hashAlgoUnknown: {},
+ hashAlgoSHA1: {
+ name: "sha1",
+ size: sha1.Size,
+ sum: func(data []byte) Hash {
+ sum := sha1.Sum(data)
+ var h Hash
+ copy(h.data[:], sum[:])
+ h.algo = hashAlgoSHA1
+ return h
+ },
+ },
+ hashAlgoSHA256: {
+ name: "sha256",
+ size: sha256.Size,
+ sum: func(data []byte) Hash {
+ sum := sha256.Sum256(data)
+ var h Hash
+ copy(h.data[:], sum[:])
+ h.algo = hashAlgoSHA256
+ return h
+ },
+ },
+}
+
+func (algo hashAlgorithm) info() hashAlgorithmDetails {
+ return hashAlgorithmTable[algo]
+}
+
+// Size returns the hash size in bytes.
+func (algo hashAlgorithm) Size() int {
+ return algo.info().size
}
// String returns the canonical name of the hash algorithm.
func (algo hashAlgorithm) String() string {
- switch algo {
- case hashAlgoSHA1:
- return "sha1"
- case hashAlgoSHA256:
- return "sha256"
- default:
+ inf := algo.info()
+ if inf.name == "" {
return "unknown"
}
+ return inf.name
+}
+
+func (algo hashAlgorithm) HexLen() int {
+ return algo.Size() * 2
+}
+
+func (algo hashAlgorithm) Sum(data []byte) Hash {
+ return algo.info().sum(data)
}
// Hash represents a Git object ID.
@@ -67,12 +82,9 @@ type Hash struct {
data [maxHashSize]byte
}
-// hashFunc is a function that computes a hash from input data.
-type hashFunc func([]byte) Hash
-
// String returns a hexadecimal string representation of the hash.
func (hash Hash) String() string {
- size := hash.algo.size()
+ size := hash.algo.Size()
if size == 0 {
return ""
}
@@ -81,7 +93,7 @@ func (hash Hash) String() string {
// Bytes returns a copy of the hash's bytes.
func (hash Hash) Bytes() []byte {
- size := hash.algo.size()
+ size := hash.algo.Size()
if size == 0 {
return nil
}
@@ -90,5 +102,21 @@ func (hash Hash) Bytes() []byte {
// Size returns the hash size.
func (hash Hash) Size() int {
- return hash.algo.size()
+ return hash.algo.Size()
+}
+
+var algoByName = map[string]hashAlgorithm{}
+
+func init() {
+ for algo, info := range hashAlgorithmTable {
+ if info.name == "" {
+ continue
+ }
+ algoByName[info.name] = hashAlgorithm(algo)
+ }
+}
+
+func parseHashAlgorithm(s string) (hashAlgorithm, bool) {
+ algo, ok := algoByName[s]
+ return algo, ok
}
diff --git a/hash_test.go b/hash_test.go
index dcbd7027..0b15fd38 100644
--- a/hash_test.go
+++ b/hash_test.go
@@ -18,7 +18,7 @@ func TestHashParse(t *testing.T) {
var validHash string
var expectedSize int
- if repo.hashAlgo.size() == 32 {
+ if repo.hashAlgo.Size() == 32 {
validHash = "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef"
expectedSize = 32
} else {
diff --git a/obj_tree.go b/obj_tree.go
index 1a63d729..07c77441 100644
--- a/obj_tree.go
+++ b/obj_tree.go
@@ -78,13 +78,13 @@ func parseTree(id Hash, body []byte, repo *Repository) (*StoredTree, error) {
nameBytes := body[i : i+nul]
i += nul + 1
- if i+repo.hashAlgo.size() > len(body) {
+ if i+repo.hashAlgo.Size() > len(body) {
return nil, errors.New("furgit: tree: truncated child hash")
}
var child Hash
- copy(child.data[:], body[i:i+repo.hashAlgo.size()])
+ copy(child.data[:], body[i:i+repo.hashAlgo.Size()])
child.algo = repo.hashAlgo
- i += repo.hashAlgo.size()
+ i += repo.hashAlgo.Size()
mode, err := strconv.ParseUint(string(modeBytes), 8, 32)
if err != nil {
diff --git a/pack_idx.go b/pack_idx.go
index c4c166ef..0dbb9bcf 100644
--- a/pack_idx.go
+++ b/pack_idx.go
@@ -163,7 +163,7 @@ func (pi *packIndex) parse(buf []byte) error {
nobj := int(readBE32(pi.fanout[len(pi.fanout)-4:]))
namesStart := fanoutEnd
- namesEnd := namesStart + nobj*pi.repo.hashAlgo.size()
+ namesEnd := namesStart + nobj*pi.repo.hashAlgo.Size()
if namesEnd > len(buf) {
return ErrInvalidObject
}
@@ -183,7 +183,7 @@ func (pi *packIndex) parse(buf []byte) error {
pi.offset32 = buf[off32Start:off32End]
off64Start := off32End
- trailerStart := len(buf) - 2*pi.repo.hashAlgo.size()
+ trailerStart := len(buf) - 2*pi.repo.hashAlgo.Size()
if trailerStart < off64Start {
return ErrInvalidObject
}
@@ -253,7 +253,7 @@ func (pi *packIndex) lookup(id Hash) (packlocation, error) {
lo = int(pi.fanoutEntry(first - 1))
}
hi := int(pi.fanoutEntry(first))
- idx, found := bsearchHash(pi.names, pi.repo.hashAlgo.size(), lo, hi, id)
+ idx, found := bsearchHash(pi.names, pi.repo.hashAlgo.Size(), lo, hi, id)
if !found {
return packlocation{}, ErrNotFound
}
diff --git a/pack_pack.go b/pack_pack.go
index 6e0806b1..628fa258 100644
--- a/pack_pack.go
+++ b/pack_pack.go
@@ -176,7 +176,7 @@ func (repo *Repository) packTypeSizeWithin(pf *packFile, ofs uint64, seen map[pa
case ObjectTypeCommit, ObjectTypeTree, ObjectTypeBlob, ObjectTypeTag:
return ty, declaredSize, nil
case ObjectTypeRefDelta:
- hashEnd := dataStart + uint64(repo.hashAlgo.size())
+ hashEnd := dataStart + uint64(repo.hashAlgo.Size())
if hashEnd > uint64(len(pf.data)) {
return ObjectTypeInvalid, 0, io.ErrUnexpectedEOF
}
@@ -273,7 +273,7 @@ func (repo *Repository) packBodyResolveWithin(pf *packFile, ofs uint64) (ObjectT
resultTy = ty
resolved = true
case ObjectTypeRefDelta:
- hashEnd := dataStart + uint64(repo.hashAlgo.size())
+ hashEnd := dataStart + uint64(repo.hashAlgo.Size())
if hashEnd > uint64(len(pf.data)) {
return fail(io.ErrUnexpectedEOF)
}
diff --git a/refs.go b/refs.go
index 372d31fd..6efdf5ec 100644
--- a/refs.go
+++ b/refs.go
@@ -70,7 +70,7 @@ func (repo *Repository) resolvePackedRef(refname string) (Ref, error) {
}
sp := bytes.IndexByte(line, ' ')
- if sp != repo.hashAlgo.size()*2 {
+ if sp != repo.hashAlgo.Size()*2 {
continue
}
@@ -428,7 +428,7 @@ func (repo *Repository) ListRefs(pattern string) ([]Ref, error) {
}
sp := bytes.IndexByte(line, ' ')
- if sp != repo.hashAlgo.size()*2 {
+ if sp != repo.hashAlgo.Size()*2 {
lastIdx = -1
continue
}
diff --git a/repo.go b/repo.go
index 8c0cd95e..4a4ebcc6 100644
--- a/repo.go
+++ b/repo.go
@@ -63,23 +63,11 @@ func OpenRepository(path string) (*Repository, error) {
algo = "sha1"
}
- var hashAlgo hashAlgorithm
- switch algo {
- case "sha1":
- hashAlgo = hashAlgoSHA1
- case "sha256":
- hashAlgo = hashAlgoSHA256
- default:
+ hashAlgo, ok := parseHashAlgorithm(algo)
+ if !ok {
return nil, fmt.Errorf("furgit: unsupported hash algorithm %q", algo)
}
- if hashAlgo.size() == 0 {
- return nil, fmt.Errorf("furgit: unsupported hash algorithm %q", algo)
- }
- if _, ok := hashFuncs[hashAlgo]; !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,
hashAlgo: hashAlgo,
@@ -130,9 +118,9 @@ func (repo *Repository) ParseHash(s string) (Hash, error) {
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.hashAlgo.size() * 2
+ expectedLen := repo.hashAlgo.Size() * 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.hashAlgo.size())
+ return id, fmt.Errorf("furgit: hash length mismatch: got %d chars, expected %d for hash size %d", len(s), expectedLen, repo.hashAlgo.Size())
}
data, err := hex.DecodeString(s)
if err != nil {
@@ -145,8 +133,7 @@ func (repo *Repository) ParseHash(s string) (Hash, error) {
// computeRawHash computes a hash from raw data using the repository's hash algorithm.
func (repo *Repository) computeRawHash(data []byte) Hash {
- hashFunc := hashFuncs[repo.hashAlgo]
- return hashFunc(data)
+ return repo.hashAlgo.Sum(data)
}
// verifyRawObject verifies a raw object against its expected hash.
diff --git a/repo_test.go b/repo_test.go
index c4a0e059..3e622e37 100644
--- a/repo_test.go
+++ b/repo_test.go
@@ -17,7 +17,7 @@ func TestRepositoryOpen(t *testing.T) {
if repo.rootPath != repoPath {
t.Errorf("rootPath: got %q, want %q", repo.rootPath, repoPath)
}
- hashSize := repo.hashAlgo.size()
+ hashSize := repo.hashAlgo.Size()
if hashSize != 32 && hashSize != 20 {
t.Errorf("hashSize: got %d, want 32 (SHA-256) or 20 (SHA-1)", hashSize)
}
generated by cgit v1.3.1-10-gc9f91 (git 2.54.0) at 2026-05-25 12:58:52 +0000