diff options
| -rw-r--r-- | refs.c | 99 | ||||
| -rw-r--r-- | refs.h | 65 |
2 files changed, 164 insertions, 0 deletions
@@ -3267,6 +3267,96 @@ static int update_ref_write(const char *action, const char *refname, return 0; } +/* + * Data structure for holding a reference transaction, which can + * consist of checks and updates to multiple references, carried out + * as atomically as possible. This structure is opaque to callers. + */ +struct ref_transaction { + struct ref_update **updates; + size_t alloc; + size_t nr; +}; + +struct ref_transaction *ref_transaction_begin(void) +{ + return xcalloc(1, sizeof(struct ref_transaction)); +} + +static void ref_transaction_free(struct ref_transaction *transaction) +{ + int i; + + for (i = 0; i < transaction->nr; i++) { + struct ref_update *update = transaction->updates[i]; + + free((char *)update->ref_name); + free(update); + } + + free(transaction->updates); + free(transaction); +} + +void ref_transaction_rollback(struct ref_transaction *transaction) +{ + ref_transaction_free(transaction); +} + +static struct ref_update *add_update(struct ref_transaction *transaction, + const char *refname) +{ + struct ref_update *update = xcalloc(1, sizeof(*update)); + + update->ref_name = xstrdup(refname); + ALLOC_GROW(transaction->updates, transaction->nr + 1, transaction->alloc); + transaction->updates[transaction->nr++] = update; + return update; +} + +void ref_transaction_update(struct ref_transaction *transaction, + const char *refname, + unsigned char *new_sha1, unsigned char *old_sha1, + int flags, int have_old) +{ + struct ref_update *update = add_update(transaction, refname); + + hashcpy(update->new_sha1, new_sha1); + update->flags = flags; + update->have_old = have_old; + if (have_old) + hashcpy(update->old_sha1, old_sha1); +} + +void ref_transaction_create(struct ref_transaction *transaction, + const char *refname, + unsigned char *new_sha1, + int flags) +{ + struct ref_update *update = add_update(transaction, refname); + + assert(!is_null_sha1(new_sha1)); + hashcpy(update->new_sha1, new_sha1); + hashclr(update->old_sha1); + update->flags = flags; + update->have_old = 1; +} + +void ref_transaction_delete(struct ref_transaction *transaction, + const char *refname, + unsigned char *old_sha1, + int flags, int have_old) +{ + struct ref_update *update = add_update(transaction, refname); + + update->flags = flags; + update->have_old = have_old; + if (have_old) { + assert(!is_null_sha1(old_sha1)); + hashcpy(update->old_sha1, old_sha1); + } +} + int update_ref(const char *action, const char *refname, const unsigned char *sha1, const unsigned char *oldval, int flags, enum action_on_err onerr) @@ -3378,6 +3468,15 @@ cleanup: return ret; } +int ref_transaction_commit(struct ref_transaction *transaction, + const char *msg, enum action_on_err onerr) +{ + int ret = update_refs(msg, transaction->updates, transaction->nr, + onerr); + ref_transaction_free(transaction); + return ret; +} + char *shorten_unambiguous_ref(const char *refname, int strict) { int i; @@ -24,6 +24,8 @@ struct ref_update { int have_old; /* 1 if old_sha1 is valid, 0 otherwise */ }; +struct ref_transaction; + /* * Bit values set in the flags argument passed to each_ref_fn(): */ @@ -220,6 +222,69 @@ enum action_on_err { UPDATE_REFS_QUIET_ON_ERR }; +/* + * Begin a reference transaction. The reference transaction must + * eventually be commited using ref_transaction_commit() or rolled + * back using ref_transaction_rollback(). + */ +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); + + +/* + * The following functions add a reference check or update to a + * ref_transaction. In all of them, refname is the name of the + * reference to be affected. The functions make internal copies of + * refname, so the caller retains ownership of the parameter. flags + * 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. + */ +void ref_transaction_update(struct ref_transaction *transaction, + const char *refname, + unsigned char *new_sha1, unsigned char *old_sha1, + int flags, int have_old); + +/* + * 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. + */ +void ref_transaction_create(struct ref_transaction *transaction, + const char *refname, + unsigned char *new_sha1, + int flags); + +/* + * 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). + */ +void ref_transaction_delete(struct ref_transaction *transaction, + const char *refname, + unsigned char *old_sha1, + int flags, int have_old); + +/* + * 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. + */ +int ref_transaction_commit(struct ref_transaction *transaction, + const char *msg, enum action_on_err onerr); + /** Lock a ref and then write its file */ int update_ref(const char *action, const char *refname, const unsigned char *sha1, const unsigned char *oldval, |