From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ronnie Sahlberg Subject: [PATCH v19 20/48] refs.c: change ref_transaction_create to do error checking and return status Date: Thu, 19 Jun 2014 08:53:02 -0700 Message-ID: <1403193210-6028-21-git-send-email-sahlberg@google.com> References: <1403193210-6028-1-git-send-email-sahlberg@google.com> Cc: Ronnie Sahlberg To: git@vger.kernel.org X-From: git-owner@vger.kernel.org Thu Jun 19 17:55:58 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 1Wxegs-0000Hk-2d for gcvg-git-2@plane.gmane.org; Thu, 19 Jun 2014 17:55:54 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933585AbaFSPzq (ORCPT ); Thu, 19 Jun 2014 11:55:46 -0400 Received: from mail-oa0-f74.google.com ([209.85.219.74]:53474 "EHLO mail-oa0-f74.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757993AbaFSPxf (ORCPT ); Thu, 19 Jun 2014 11:53:35 -0400 Received: by mail-oa0-f74.google.com with SMTP id i7so694340oag.3 for ; Thu, 19 Jun 2014 08:53:33 -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=ksJtvdLzxpa4dzpg9UjuWnQTFiL8xF+ZnW1g0t91Oyw=; b=pkrW2B8r+OdwF/4U5hYUurFRRIHwUj+uARzUF69V60cYTrjEXm9SIgqzIu113lookL Wl7vS5EOcr3CMMIbsudXytVNL9niUWTETiunmSj0NBQ59J8qrBINShaOmYL6vh7g51WG 9L7xWOGLczxtvIy1EMeZxLlTeetbJ02dfgAKYKEYZpa6b8Tk3cAYCLZ5aldgQ639TmD/ wWQtlI4UI7zgFJ0jf4loUY0GEVLvRF5Rx8fOOuJwWhLA48/Fa7KL5d7REiiGcTFjWOf5 SM6vLbFo7fdKYPd+ihpm/X4Sp4YI5jUcw5Pc8yoTsvSc5RfmLJQO8pQ6+6sG6CMNQNeH trMg== 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=ksJtvdLzxpa4dzpg9UjuWnQTFiL8xF+ZnW1g0t91Oyw=; b=GPnlByQItz95DLqAT09w5qDDbexgewIhKuL5JXRDlqSj1S8L6rGj9IUKktPzTNORUc TXmU0M/itNDun+QWrjMB7ulZ7SkRmxtNtDlAZDY/PEjYc8Dm3n/SrsJdcK4TsW+F+1No 9dL1oScuBC3G4YwiDWi84WQwf+zIcavZIPJE19GgCr+ebHQmFL9Xs3OXoaYSH21w1TUt pLYJJdEFELiY1g/pvDFO6abXzcZh0MT4EXzYdblNaJJRIddez1nTc29+AqylubhEk9St 8HkPFXoFIYzJ91VdJPJjfwXFj1iYcLCVm7GlGVtHg24WIDFzjKoHbLoaPE8uw0Y38q25 X1OQ== X-Gm-Message-State: ALoCoQlx3F/UWIV8vwi5u7hfKPhW+oJhkVFXWFN0gF22pOrujgW50EuNxUce4Aqo/hxsT4Yz1pR0 X-Received: by 10.50.85.102 with SMTP id g6mr4545076igz.8.1403193213529; Thu, 19 Jun 2014 08:53:33 -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 o69si418783yhp.6.2014.06.19.08.53.33 for (version=TLSv1.1 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Thu, 19 Jun 2014 08:53:33 -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 50DE45A4435; Thu, 19 Jun 2014 08:53:33 -0700 (PDT) Received: by sahlberg1.mtv.corp.google.com (Postfix, from userid 177442) id 21204E1106; Thu, 19 Jun 2014 08:53:33 -0700 (PDT) X-Mailer: git-send-email 2.0.0.438.g337c581 In-Reply-To: <1403193210-6028-1-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); -- 2.0.0.438.g337c581