From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ronnie Sahlberg Subject: [PATCH 01/20] refs.c: change ref_transaction_create to do error checking and return status Date: Tue, 15 Jul 2014 16:33:59 -0700 Message-ID: <1405467258-24102-2-git-send-email-sahlberg@google.com> References: <1405467258-24102-1-git-send-email-sahlberg@google.com> Cc: mhagger@alum.mit.edu, Ronnie Sahlberg To: git@vger.kernel.org X-From: git-owner@vger.kernel.org Wed Jul 16 01:34:57 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 1X7CFN-0003Pj-5d for gcvg-git-2@plane.gmane.org; Wed, 16 Jul 2014 01:34:57 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934340AbaGOXef (ORCPT ); Tue, 15 Jul 2014 19:34:35 -0400 Received: from mail-pd0-f201.google.com ([209.85.192.201]:64945 "EHLO mail-pd0-f201.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934222AbaGOXeX (ORCPT ); Tue, 15 Jul 2014 19:34:23 -0400 Received: by mail-pd0-f201.google.com with SMTP id v10so40109pde.2 for ; Tue, 15 Jul 2014 16:34:23 -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=pX34y82P+M3cQmA0J3vSY70rKztdWRJwcqrjwuys0TA=; b=f/fYOg8kcTuxl1G7CRPJmaaJQLqizELGTMVJPqs8sRzl++Jx4GKb9H2TiDysusSKAI BJx4lOu1xZOmwZbERuoqgsEVoELJMccNt6fT0s5DEHB0Jsd3ld1/1wbrOr7P/AWy0i7x mIdGq2wzd+C3hWici33uWlLjrxDr5GfD3NV10TTnID1fnsyh/vliFcJZK7v8S4XL+f+B cCrHWgzAr0gEj+BjVAILcv+85fGfmu2y77ow2CeVCprp+gXs5th4ymXydD5i4M3LX8o0 J+abRTvk36lMOvBDHMo4MH5gv4rksW0QAGWT84eJoopiU7H6FmV6unrWPi1kPoIB8aEe mPeQ== 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=pX34y82P+M3cQmA0J3vSY70rKztdWRJwcqrjwuys0TA=; b=NGXMiB3x+Fn5/AiczPSesk76SPdBXwlVZewlEgml97eJeCW4j3yEfVEh1CWl9Vihkd 9FlTsKV8vVWJ1ThhlQifBBX1jC7MjjfHBwjJV2q0s4Nj2UBRpKTi5tiQEMCy2mxd6R6M xm1Ki2Dph/nirnkyGjcudTCNuMwhGXYd4KXizR4i+Acidky1UuKXR7VAizs/2CBQB3wI atq6y1c3z0JXuL5wpg0Z88QTqJjgw+/rG2CGKSbOUtTgQIW2Kz7u0REiIlREdcuuqUrs ityAm8uLL+BturSPT1IR+msft0uBlIBCsIaqIefPx9vn+kZhnmZA98yYMCO3WoloJhEJ gl2A== X-Gm-Message-State: ALoCoQn4yUkKPo2awC+vVDyNejpB3BZUgd+Zlo5MkasxsunPd7PmmThH6wC/cztyflXg0u/M/RdL X-Received: by 10.66.121.2 with SMTP id lg2mr12607583pab.43.1405467263205; Tue, 15 Jul 2014 16:34:23 -0700 (PDT) Received: from corp2gmr1-1.hot.corp.google.com (corp2gmr1-1.hot.corp.google.com [172.24.189.92]) by gmr-mx.google.com with ESMTPS id y50si1060118yhk.4.2014.07.15.16.34.23 for (version=TLSv1.1 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 15 Jul 2014 16:34:23 -0700 (PDT) Received: from sahlberg1.mtv.corp.google.com (sahlberg1.mtv.corp.google.com [172.27.69.52]) by corp2gmr1-1.hot.corp.google.com (Postfix) with ESMTP id F02A231C2EA; Tue, 15 Jul 2014 16:34:22 -0700 (PDT) Received: by sahlberg1.mtv.corp.google.com (Postfix, from userid 177442) id 99B3CE0C77; Tue, 15 Jul 2014 16:34:21 -0700 (PDT) X-Mailer: git-send-email 2.0.1.481.gb244468 In-Reply-To: <1405467258-24102-1-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 | 48 +++++++++++++++++++++++++++++++++++++++++------- 3 files changed, 56 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..b648819 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); -- 2.0.1.442.g7fe6834.dirty