refs: new transaction related ref-store api

The transaction struct now takes a ref store at creation and will
operate on that ref store alone.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

refs.c

@@ -630,16 +630,20 @@ static int delete_pseudoref(const char *pseudoref, const unsigned char *old_sha1
 	return 0;
 }
 
-int delete_ref(const char *msg, const char *refname,
-	       const unsigned char *old_sha1, unsigned int flags)
+int refs_delete_ref(struct ref_store *refs, const char *msg,
+		    const char *refname,
+		    const unsigned char *old_sha1,
+		    unsigned int flags)
 {
 	struct ref_transaction *transaction;
 	struct strbuf err = STRBUF_INIT;
 
-	if (ref_type(refname) == REF_TYPE_PSEUDOREF)
+	if (ref_type(refname) == REF_TYPE_PSEUDOREF) {
+		assert(refs == get_main_ref_store());
 		return delete_pseudoref(refname, old_sha1);
+	}
 
-	transaction = ref_transaction_begin(&err);
+	transaction = ref_store_transaction_begin(refs, &err);
 	if (!transaction ||
 	    ref_transaction_delete(transaction, refname, old_sha1,
 				   flags, msg, &err) ||
@@ -654,6 +658,13 @@ int delete_ref(const char *msg, const char *refname,
 	return 0;
 }
 
+int delete_ref(const char *msg, const char *refname,
+	       const unsigned char *old_sha1, unsigned int flags)
+{
+	return refs_delete_ref(get_main_ref_store(), msg, refname,
+			       old_sha1, flags);
+}
+
 int copy_reflog_msg(char *buf, const char *msg)
 {
 	char *cp = buf;
@@ -813,11 +824,20 @@ int read_ref_at(const char *refname, unsigned int flags, unsigned long at_time,
 	return 1;
 }
 
-struct ref_transaction *ref_transaction_begin(struct strbuf *err)
+struct ref_transaction *ref_store_transaction_begin(struct ref_store *refs,
+						    struct strbuf *err)
 {
+	struct ref_transaction *tr;
 	assert(err);
 
-	return xcalloc(1, sizeof(struct ref_transaction));
+	tr = xcalloc(1, sizeof(struct ref_transaction));
+	tr->ref_store = refs;
+	return tr;
+}
+
+struct ref_transaction *ref_transaction_begin(struct strbuf *err)
+{
+	return ref_store_transaction_begin(get_main_ref_store(), err);
 }
 
 void ref_transaction_free(struct ref_transaction *transaction)
@@ -934,18 +954,20 @@ int update_ref_oid(const char *msg, const char *refname,
 		old_oid ? old_oid->hash : NULL, flags, onerr);
 }
 
-int update_ref(const char *msg, const char *refname,
-	       const unsigned char *new_sha1, const unsigned char *old_sha1,
-	       unsigned int flags, enum action_on_err onerr)
+int refs_update_ref(struct ref_store *refs, const char *msg,
+		    const char *refname, const unsigned char *new_sha1,
+		    const unsigned char *old_sha1, unsigned int flags,
+		    enum action_on_err onerr)
 {
 	struct ref_transaction *t = NULL;
 	struct strbuf err = STRBUF_INIT;
 	int ret = 0;
 
 	if (ref_type(refname) == REF_TYPE_PSEUDOREF) {
+		assert(refs == get_main_ref_store());
 		ret = write_pseudoref(refname, new_sha1, old_sha1, &err);
 	} else {
-		t = ref_transaction_begin(&err);
+		t = ref_store_transaction_begin(refs, &err);
 		if (!t ||
 		    ref_transaction_update(t, refname, new_sha1, old_sha1,
 					   flags, msg, &err) ||
@@ -976,6 +998,15 @@ int update_ref(const char *msg, const char *refname,
 	return 0;
 }
 
+int update_ref(const char *msg, const char *refname,
+	       const unsigned char *new_sha1,
+	       const unsigned char *old_sha1,
+	       unsigned int flags, enum action_on_err onerr)
+{
+	return refs_update_ref(get_main_ref_store(), msg, refname, new_sha1,
+			       old_sha1, flags, onerr);
+}
+
 char *shorten_unambiguous_ref(const char *refname, int strict)
 {
 	int i;
@@ -1607,7 +1638,7 @@ int create_symref(const char *ref_target, const char *refs_heads_master,
 int ref_transaction_commit(struct ref_transaction *transaction,
 			   struct strbuf *err)
 {
-	struct ref_store *refs = get_main_ref_store();
+	struct ref_store *refs = transaction->ref_store;
 
 	return refs->be->transaction_commit(refs, transaction, err);
 }
@@ -1726,7 +1757,7 @@ int reflog_expire(const char *refname, const unsigned char *sha1,
 int initial_ref_transaction_commit(struct ref_transaction *transaction,
 				   struct strbuf *err)
 {
-	struct ref_store *refs = get_main_ref_store();
+	struct ref_store *refs = transaction->ref_store;
 
 	return refs->be->initial_transaction_commit(refs, transaction, err);
 }

refs.h

@@ -333,6 +333,10 @@ int reflog_exists(const char *refname);
  * exists, regardless of its old value. It is an error for old_sha1 to
  * be NULL_SHA1. flags is passed through to ref_transaction_delete().
  */
+int refs_delete_ref(struct ref_store *refs, const char *msg,
+		    const char *refname,
+		    const unsigned char *old_sha1,
+		    unsigned int flags);
 int delete_ref(const char *msg, const char *refname,
 	       const unsigned char *old_sha1, unsigned int flags);
 
@@ -418,6 +422,8 @@ enum action_on_err {
  * Begin a reference transaction.  The reference transaction must
  * be freed by calling ref_transaction_free().
  */
+struct ref_transaction *ref_store_transaction_begin(struct ref_store *refs,
+						    struct strbuf *err);
 struct ref_transaction *ref_transaction_begin(struct strbuf *err);
 
 /*
@@ -552,6 +558,9 @@ void ref_transaction_free(struct ref_transaction *transaction);
  * ref_transaction_update(). Handle errors as requested by the `onerr`
  * argument.
  */
+int refs_update_ref(struct ref_store *refs, const char *msg, const char *refname,
+		    const unsigned char *new_sha1, const unsigned char *old_sha1,
+		    unsigned int flags, enum action_on_err onerr);
 int update_ref(const char *msg, const char *refname,
 	       const unsigned char *new_sha1, const unsigned char *old_sha1,
 	       unsigned int flags, enum action_on_err onerr);

refs/refs-internal.h

@@ -200,6 +200,7 @@ enum ref_transaction_state {
  * as atomically as possible.  This structure is opaque to callers.
  */
 struct ref_transaction {
+	struct ref_store *ref_store;
 	struct ref_update **updates;
 	size_t alloc;
 	size_t nr;