From bd91bf5f3bcffe5d1023ab9a37e4a9425830aba9 Mon Sep 17 00:00:00 2001
From: Runxi Yu
Date: Sun, 16 Nov 2025 00:00:00 +0000
Subject: hash: Make fewer helper functions need explicit hash length fields

---
 loose.go | 42 +++++++++++++++++++++++++++++-------------
 1 file changed, 29 insertions(+), 13 deletions(-)

(limited to 'loose.go')

diff --git a/loose.go b/loose.go
index c1371991..d79b2f48 100644
--- a/loose.go
+++ b/loose.go
@@ -12,9 +12,13 @@ import (
 
 const looseHeaderLimit = 4096
 
-func loosePath(id Hash, hashSize int) string {
-	hex := id.StringWithSize(hashSize)
-	return filepath.Join("objects", hex[:2], hex[2:])
+// loosePath returns the path for a loose object, validating hash size.
+func (repo *Repository) loosePath(id Hash) (string, error) {
+	if id.size != repo.HashSize {
+		return "", fmt.Errorf("furgit: hash size mismatch: got %d, expected %d", id.size, repo.HashSize)
+	}
+	hex := id.String()
+	return filepath.Join("objects", hex[:2], hex[2:]), nil
 }
 
 func (repo *Repository) looseRead(id Hash) (Object, error) {
@@ -22,11 +26,15 @@ func (repo *Repository) looseRead(id Hash) (Object, error) {
 	if err != nil {
 		return nil, err
 	}
-	return parseObjectBody(ty, id, body, repo.HashSize)
+	return parseObjectBody(ty, id, body, repo)
 }
 
 func (repo *Repository) looseReadTyped(id Hash) (ObjType, []byte, error) {
-	path := repo.repoPath(loosePath(id, repo.HashSize))
+	path, err := repo.loosePath(id)
+	if err != nil {
+		return ObjInvalid, nil, err
+	}
+	path = repo.repoPath(path)
 	f, err := os.Open(path)
 	if err != nil {
 		if os.IsNotExist(err) {
@@ -62,7 +70,7 @@ func (repo *Repository) looseReadTyped(id Hash) (ObjType, []byte, error) {
 	if declaredSize != int64(len(body)) {
 		return ObjInvalid, nil, ErrInvalidObject
 	}
-	if !verifyRawObject(raw, id, repo.HashSize) {
+	if !repo.verifyRawObject(raw, id) {
 		return ObjInvalid, nil, ErrInvalidObject
 	}
 
@@ -71,7 +79,11 @@ func (repo *Repository) looseReadTyped(id Hash) (ObjType, []byte, error) {
 }
 
 func (repo *Repository) looseTypeSize(id Hash) (ObjType, int64, error) {
-	path := repo.repoPath(loosePath(id, repo.HashSize))
+	path, err := repo.loosePath(id)
+	if err != nil {
+		return ObjInvalid, 0, err
+	}
+	path = repo.repoPath(path)
 	// #nosec G304
 	f, err := os.Open(path)
 	if err != nil {
@@ -161,13 +173,13 @@ func (repo *Repository) WriteLooseObject(obj Object) (Hash, error) {
 
 	switch o := obj.(type) {
 	case *Blob:
-		raw, err = o.Serialize(repo.HashSize)
+		raw, err = o.Serialize()
 	case *Tree:
-		raw, err = o.Serialize(repo.HashSize)
+		raw, err = o.Serialize()
 	case *Commit:
-		raw, err = o.Serialize(repo.HashSize)
+		raw, err = o.Serialize()
 	case *Tag:
-		raw, err = o.Serialize(repo.HashSize)
+		raw, err = o.Serialize()
 	default:
 		return Hash{}, fmt.Errorf("furgit: unsupported object type for writing: %T", obj)
 	}
@@ -177,8 +189,12 @@ func (repo *Repository) WriteLooseObject(obj Object) (Hash, error) {
 		return Hash{}, err
 	}
 
-	id := computeRawHash(raw, repo.HashSize)
-	path := repo.repoPath(loosePath(id, repo.HashSize))
+	id := repo.computeRawHash(raw)
+	path, err := repo.loosePath(id)
+	if err != nil {
+		return Hash{}, err
+	}
+	path = repo.repoPath(path)
 
 	if err := os.MkdirAll(filepath.Dir(path), 0o755); err != nil {
 		return Hash{}, err
-- 
cgit v1.3.1-10-gc9f91