From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ronnie Sahlberg Subject: [PATCH v20 20/48] refs.c: change ref_transaction_create to do error checking and return status Date: Fri, 20 Jun 2014 07:43:01 -0700 Message-ID: <1403275409-28173-21-git-send-email-sahlberg@google.com> References: <1403275409-28173-1-git-send-email-sahlberg@google.com> Cc: Ronnie Sahlberg To: git@vger.kernel.org X-From: git-owner@vger.kernel.org Fri Jun 20 16:47:08 2014 Return-path: Envelope-to: gcvg-git-2@plane.gmane.org Received: from vger.kernel.org ([209.132.180.67]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1Wy05o-0004LJ-AA for gcvg-git-2@plane.gmane.org; Fri, 20 Jun 2014 16:47:04 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754211AbaFTOqS (ORCPT ); Fri, 20 Jun 2014 10:46:18 -0400 Received: from mail-ie0-f201.google.com ([209.85.223.201]:42964 "EHLO mail-ie0-f201.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753201AbaFTOne (ORCPT ); Fri, 20 Jun 2014 10:43:34 -0400 Received: by mail-ie0-f201.google.com with SMTP id lx4so979782iec.0 for ; Fri, 20 Jun 2014 07:43:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20120113; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=kHsQBc61WX4W0Ulyx0tZg227UzOxAkI9G0XaMeYLwd0=; b=eM0EpVizpAVqKRQNixgrEXrdU0hSKc9YMkJ8s6iNUyibHAzLf8ORAuI9Am9+KWurfO kPeTzsiYbyarxRSuHq9ouEDtM1pml+WoAuX+15uPdc7USSw7Gm//lSpSAa2zq7CvQSPF U9QDk/VmlxwlBJZTgXMHTogZ3IJ59I3aawATT9L7N8PWAXYu7NXjyla7qIm4cgwE0eoe L2uunhGmsEpXla3hTNIAtPK2OfPVY2rKn0H9xM9OHbcfBOytDNMUwEl7AA5NedDOJw95 CyWjdp6A7tmAMKWbb45LL16/LE6BabtGJGGhVdZRStbVmSxxSPkD3H7w4tjn+PVp+znF aXvQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=kHsQBc61WX4W0Ulyx0tZg227UzOxAkI9G0XaMeYLwd0=; b=MHoQt8jZZ36l7RTSPMBvgT051Hevmi0rdjy2zNlFDZU1CNvvWxKGvJ1tueKpSibr37 +KgOqqeHE29z6iElZx4ethhDU51gyHf9G3JScUUtkEnd3oDSndlMdpOFmrxY/ecxF3ed s5OU0+CLIDMznekSIGmMVWFumClcjhkn3h3irbtj+XEm/NUJQSQo1iUSP9lQ8qGwbQ7O cCM9k4KP9B6ndj/vle1+yLInI/xilHcv8kKcKOIxKM80dB0s7ruObVohuKvSjErvog8V jobZ8hQ66XyQCivYm1hsa2xbCERk6SFkUjbd0q8PoBq6+NfThOPos4k1jF8GSJ7ngu9N Z6qQ== X-Gm-Message-State: ALoCoQlOd+AC2QzdSwxFb43szjAJ3DjOGJQbzo1Gl6zr0Peh4Z8PZ+WA/UTA1KEoewAQ3EhzJiyl X-Received: by 10.42.249.207 with SMTP id ml15mr1399320icb.21.1403275412898; Fri, 20 Jun 2014 07:43:32 -0700 (PDT) Received: from corp2gmr1-2.hot.corp.google.com (corp2gmr1-2.hot.corp.google.com [172.24.189.93]) by gmr-mx.google.com with ESMTPS id j43si432420yhh.5.2014.06.20.07.43.32 for (version=TLSv1.1 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Fri, 20 Jun 2014 07:43:32 -0700 (PDT) Received: from sahlberg1.mtv.corp.google.com (sahlberg1.mtv.corp.google.com [172.27.69.52]) by corp2gmr1-2.hot.corp.google.com (Postfix) with ESMTP id AB9185A44A6; Fri, 20 Jun 2014 07:43:32 -0700 (PDT) Received: by sahlberg1.mtv.corp.google.com (Postfix, from userid 177442) id 87C08E15A5; Fri, 20 Jun 2014 07:43:32 -0700 (PDT) X-Mailer: git-send-email 2.0.0.420.g181e020.dirty In-Reply-To: <1403275409-28173-1-git-send-email-sahlberg@google.com> Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Archived-At: 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. Reviewed-by: Jonathan Nieder Signed-off-by: Ronnie Sahlberg --- builtin/update-ref.c | 4 +++- refs.c | 18 +++++++++++------ refs.h | 55 +++++++++++++++++++++++++++++++++++++++++++++------- 3 files changed, 63 insertions(+), 14 deletions(-) diff --git a/builtin/update-ref.c b/builtin/update-ref.c index 3067b11..41121fa 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 3f05e88..c49f1c6 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 c5376ce..33b4383 100644 --- a/refs.h +++ b/refs.h @@ -10,6 +10,45 @@ 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. + * This allows the caller to prepare preamble text to the generated + * error message: + * + * strbuf_addf(&err, "Error while doing foo-bar: "); + * if (ref_transaction_update(..., &err)) { + * ret = error("%s", err.buf); + * goto cleanup; + * } + */ struct ref_transaction; /* @@ -248,7 +287,7 @@ 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 +301,15 @@ 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 +325,6 @@ 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); -- 2.0.0.420.g181e020.dirty