diff options
Diffstat (limited to 'refs.h')
| -rw-r--r-- | refs.h | 48 |
1 files changed, 41 insertions, 7 deletions
@@ -10,6 +10,38 @@ struct ref_lock { 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; /* @@ -248,7 +280,7 @@ struct ref_transaction *ref_transaction_begin(void); * 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. On failure the err buffer will be updated. + * rolled back. */ int ref_transaction_update(struct ref_transaction *transaction, const char *refname, @@ -262,11 +294,15 @@ int ref_transaction_update(struct ref_transaction *transaction, * 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, - const 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 @@ -282,8 +318,6 @@ void ref_transaction_delete(struct ref_transaction *transaction, * Commit all of the changes that have been queued in transaction, as * atomically as possible. Return a nonzero value if there is a * problem. - * If err is non-NULL we will add an error string to it to explain why - * the transaction failed. The string does not end in newline. */ int ref_transaction_commit(struct ref_transaction *transaction, const char *msg, struct strbuf *err); |