From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ronnie Sahlberg Subject: [PATCH v14 13/40] refs.c: change ref_transaction_create to do error checking and return status Date: Fri, 6 Jun 2014 15:28:51 -0700 Message-ID: <1402093758-3162-14-git-send-email-sahlberg@google.com> References: <1402093758-3162-1-git-send-email-sahlberg@google.com> Cc: Ronnie Sahlberg To: git@vger.kernel.org X-From: git-owner@vger.kernel.org Sat Jun 07 00:29:49 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 1Wt2du-0002LL-Sg for gcvg-git-2@plane.gmane.org; Sat, 07 Jun 2014 00:29:47 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752595AbaFFW3e (ORCPT ); Fri, 6 Jun 2014 18:29:34 -0400 Received: from mail-ob0-f202.google.com ([209.85.214.202]:48702 "EHLO mail-ob0-f202.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752471AbaFFW3W (ORCPT ); Fri, 6 Jun 2014 18:29:22 -0400 Received: by mail-ob0-f202.google.com with SMTP id wm4so742273obc.3 for ; Fri, 06 Jun 2014 15:29:22 -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=DaNvoHEyGyMGp0HhOfneg/yvYcnRfN7yoKwydAAjoT8=; b=XejIj0EAKKijW8hxi1Qu1G7XNx1bkdsLQacA/BytGqKFJJh1/5G7R/7fx/UXYnsnen 8kmWSr2tRqGsF3++ZZiSb+w9emE+FfNI2+8vz+phrtpK0O09laJkyHLyvuwKgrtf1IWV p/5bUlil+eb37V4NHVG3b3+jjO+wyC+sYIF2ZEoFsOZLwxdwi/9dNt1idAgIGYmYaGQh XU8K+lA0xefo7Onej0XdWX9Ak/LsCQjQ15QjfwhJYvsfIMI58AnDaRoADLrzhBWDeyI+ 5pwEeLKtM4ytK+4T3UNtcYYpZWdmmD12fyvDxX+dy+IkV4B2ywYib+YxxH51R4FuK8dF K3vg== 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=DaNvoHEyGyMGp0HhOfneg/yvYcnRfN7yoKwydAAjoT8=; b=PS75cKZPijMJLZp70p5FtiZAQRMIUuJg1BXY/wONk2NzOHd/Iz10/N22ZPJIIh4tnC 7Y/fHhcNAuxlWupl/lEhjJ0qVX/isooTnXAJYMHpT4oY8NotEVzmhklaDV3xrIZAPxUp pLD4A5noEn05VNNJuvxKZ8Zm/40xaWIZGiWffOvTTaIX47rHVPuUf+kWzhTj0CHTGeCl rto9ZPh1wPcJ7mvtUfjY0u3rnuNmCSkc3xAuc2b2EMEnKI4XHqX2YGHlRSV2PmpdyHkt oDTADUHfqbC2X3geWUwRSrZUItb6S0Q/tGgf05hAcfOOIG5O9xiw9MEV1nlIQZOhtPwn QYDQ== X-Gm-Message-State: ALoCoQkV1yrITAtvcVqXvwRQWPyI+MiN/w/dgGRhmObpNU1ZbCKGq1N5Kplru4xcPaElg/oiftwi X-Received: by 10.182.86.5 with SMTP id l5mr4567748obz.32.1402093762364; Fri, 06 Jun 2014 15:29:22 -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 pr8si750954vdb.1.2014.06.06.15.29.22 for (version=TLSv1.1 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Fri, 06 Jun 2014 15:29:22 -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 0F1855A4515; Fri, 6 Jun 2014 15:29:22 -0700 (PDT) Received: by sahlberg1.mtv.corp.google.com (Postfix, from userid 177442) id DF71BE109D; Fri, 6 Jun 2014 15:29:21 -0700 (PDT) X-Mailer: git-send-email 2.0.0.582.ge25c160 In-Reply-To: <1402093758-3162-1-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 f5e7a12..3cb99f6 100644 --- a/refs.c +++ b/refs.c @@ -3439,18 +3439,24 @@ 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 32edf3f..bda790e6 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; /* @@ -236,7 +275,7 @@ 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, @@ -250,11 +289,15 @@ 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 @@ -270,8 +313,6 @@ 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); -- 2.0.0.582.ge25c160