int force_write;
};
+/*
+ * A ref_transaction represents a collection of ref updates
+ * that should succeed or fail together.
+ *
+ * Calling sequence
+ * ----------------
+ * - Allocate and initialize a `struct ref_transaction` by calling
+ * `ref_transaction_begin()`.
+ *
+ * - List intended ref updates by calling functions like
+ * `ref_transaction_update()` and `ref_transaction_create()`.
+ *
+ * - Call `ref_transaction_commit()` to execute the transaction.
+ * If this succeeds, the ref updates will have taken place and
+ * the transaction cannot be rolled back.
+ *
+ * - At any time call `ref_transaction_free()` to discard the
+ * transaction and free associated resources. In particular,
+ * this rolls back the transaction if it has not been
+ * successfully committed.
+ *
+ * Error handling
+ * --------------
+ *
+ * On error, transaction functions append a message about what
+ * went wrong to the 'err' argument. The message mentions what
+ * ref was being updated (if any) when the error occurred so it
+ * can be passed to 'die' or 'error' as-is.
+ *
+ * The message is appended to err without first clearing err.
+ * err will not be '\n' terminated.
+ */
struct ref_transaction;
/*
/*
* Lock the packed-refs file for writing. Flags is passed to
* hold_lock_file_for_update(). Return 0 on success.
+ * Errno is set to something meaningful on error.
*/
extern int lock_packed_refs(int flags);
* Write the current version of the packed refs cache from memory to
* disk. The packed-refs file must already be locked for writing (see
* lock_packed_refs()). Return zero on success.
+ * Sets errno to something meaningful on error.
*/
extern int commit_packed_refs(void);
*/
int pack_refs(unsigned int flags);
-extern int repack_without_refs(const char **refnames, int n);
+extern int repack_without_refs(const char **refnames, int n,
+ struct strbuf *err);
extern int ref_exists(const char *);
+extern int is_branch(const char *refname);
+
/*
* If refname is a non-symbolic reference that refers to a tag object,
* and the tag can be (recursively) dereferenced to a non-tag object,
*/
extern int peel_ref(const char *refname, unsigned char *sha1);
-/** Locks a "refs/" ref returning the lock on success and NULL on failure. **/
-extern struct ref_lock *lock_ref_sha1(const char *refname, const unsigned char *old_sha1);
-
-/** Locks any ref (for 'HEAD' type refs). */
+/*
+ * Flags controlling lock_any_ref_for_update(), ref_transaction_update(),
+ * ref_transaction_create(), etc.
+ * REF_NODEREF: act on the ref directly, instead of dereferencing
+ * symbolic references.
+ *
+ * Flags >= 0x100 are reserved for internal use.
+ */
#define REF_NODEREF 0x01
+/*
+ * This function sets errno to something meaningful on failure.
+ */
extern struct ref_lock *lock_any_ref_for_update(const char *refname,
const unsigned char *old_sha1,
int flags, int *type_p);
/** Writes sha1 into the ref specified by the lock. **/
extern int write_ref_sha1(struct ref_lock *lock, const unsigned char *sha1, const char *msg);
-/** Setup reflog before using. **/
+/*
+ * Setup reflog before using. Set errno to something meaningful on failure.
+ */
int log_ref_setup(const char *refname, char *logfile, int bufsize);
/** Reads log for the value of ref during at_time. **/
/*
* Begin a reference transaction. The reference transaction must
- * eventually be commited using ref_transaction_commit() or rolled
- * back using ref_transaction_rollback().
+ * be freed by calling ref_transaction_free().
*/
-struct ref_transaction *ref_transaction_begin(void);
-
-/*
- * Roll back a ref_transaction and free all associated data.
- */
-void ref_transaction_rollback(struct ref_transaction *transaction);
-
+struct ref_transaction *ref_transaction_begin(struct strbuf *err);
/*
* The following functions add a reference check or update to a
* can be REF_NODEREF; it is passed to update_ref_lock().
*/
-
/*
* Add a reference update to transaction. new_sha1 is the value that
* the reference should have after the update, or zeros if it should
* be deleted. If have_old is true, then old_sha1 holds the value
* that the reference should have had before the update, or zeros if
* it must not have existed beforehand.
+ * Function returns 0 on success and non-zero on failure. A failure to update
+ * means that the transaction as a whole has failed and will need to be
+ * rolled back.
*/
-void ref_transaction_update(struct ref_transaction *transaction,
- const char *refname,
- unsigned char *new_sha1, unsigned char *old_sha1,
- int flags, int have_old);
+int ref_transaction_update(struct ref_transaction *transaction,
+ const char *refname,
+ const unsigned char *new_sha1,
+ const unsigned char *old_sha1,
+ int flags, int have_old,
+ struct strbuf *err);
/*
* Add a reference creation to transaction. new_sha1 is the value
* that the reference should have after the update; it must not be the
* null SHA-1. It is verified that the reference does not exist
* already.
+ * Function returns 0 on success and non-zero on failure. A failure to create
+ * means that the transaction as a whole has failed and will need to be
+ * rolled back.
*/
-void ref_transaction_create(struct ref_transaction *transaction,
- const char *refname,
- unsigned char *new_sha1,
- int flags);
+int ref_transaction_create(struct ref_transaction *transaction,
+ const char *refname,
+ const unsigned char *new_sha1,
+ int flags,
+ struct strbuf *err);
/*
* Add a reference deletion to transaction. If have_old is true, then
* old_sha1 holds the value that the reference should have had before
* the update (which must not be the null SHA-1).
+ * Function returns 0 on success and non-zero on failure. A failure to delete
+ * means that the transaction as a whole has failed and will need to be
+ * rolled back.
*/
-void ref_transaction_delete(struct ref_transaction *transaction,
- const char *refname,
- unsigned char *old_sha1,
- int flags, int have_old);
+int ref_transaction_delete(struct ref_transaction *transaction,
+ const char *refname,
+ const unsigned char *old_sha1,
+ int flags, int have_old,
+ struct strbuf *err);
/*
* Commit all of the changes that have been queued in transaction, as
* atomically as possible. Return a nonzero value if there is a
- * problem. The ref_transaction is freed by this function.
+ * problem.
*/
int ref_transaction_commit(struct ref_transaction *transaction,
- const char *msg, enum action_on_err onerr);
+ const char *msg, struct strbuf *err);
+
+/*
+ * Free an existing transaction and all associated data.
+ */
+void ref_transaction_free(struct ref_transaction *transaction);
/** Lock a ref and then write its file */
int update_ref(const char *action, const char *refname,