From b416af5bcdca3ac8426220f09efbfca2f1bec6e0 Mon Sep 17 00:00:00 2001 From: Ronnie Sahlberg Date: Wed, 16 Apr 2014 15:26:44 -0700 Subject: [PATCH] refs.c: change ref_transaction_create to do error checking and return status Do basic error checking in ref_transaction_create() and make it return non-zero on error. Update all callers to check the result of ref_transaction_create(). There are currently no conditions in _create that will return error but there will be in the future. Add an err argument that will be updated on failure. Signed-off-by: Ronnie Sahlberg Reviewed-by: Michael Haggerty Signed-off-by: Jonathan Nieder Signed-off-by: Junio C Hamano --- builtin/update-ref.c | 4 +++- refs.c | 18 ++++++++++++------ refs.h | 48 +++++++++++++++++++++++++++++++++++++++++------- 3 files changed, 56 insertions(+), 14 deletions(-) diff --git a/builtin/update-ref.c b/builtin/update-ref.c index 3067b11310..41121fa37b 100644 --- a/builtin/update-ref.c +++ b/builtin/update-ref.c @@ -226,7 +226,9 @@ static const char *parse_cmd_create(struct strbuf *input, const char *next) if (*next != line_termination) die("create %s: extra input: %s", refname, next); - ref_transaction_create(transaction, refname, new_sha1, update_flags); + if (ref_transaction_create(transaction, refname, new_sha1, + update_flags, &err)) + die("%s", err.buf); update_flags = 0; free(refname); diff --git a/refs.c b/refs.c index 3f05e88329..c49f1c609a 100644 --- a/refs.c +++ b/refs.c @@ -3449,18 +3449,24 @@ int ref_transaction_update(struct ref_transaction *transaction, return 0; } -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) { - struct ref_update *update = add_update(transaction, refname); + struct ref_update *update; + + if (!new_sha1 || is_null_sha1(new_sha1)) + die("BUG: create ref with null new_sha1"); + + 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; + return 0; } void ref_transaction_delete(struct ref_transaction *transaction, diff --git a/refs.h b/refs.h index c5376cee8d..b648819a2f 100644 --- a/refs.h +++ b/refs.h @@ -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); -- 2.11.4.GIT