From nobody Sun Oct 5 19:25:53 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1519933717131266.13341504816447; Thu, 1 Mar 2018 11:48:37 -0800 (PST) Received: from localhost ([::1]:58955 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1erUBw-0004Ye-65 for importer@patchew.org; Thu, 01 Mar 2018 14:48:36 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:40481) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1erU6o-0000ot-Bs for qemu-devel@nongnu.org; Thu, 01 Mar 2018 14:43:19 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1erU6n-0007WG-G5 for qemu-devel@nongnu.org; Thu, 01 Mar 2018 14:43:18 -0500 Received: from mx1.redhat.com ([209.132.183.28]:55700) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1erU6n-0007Uh-9C for qemu-devel@nongnu.org; Thu, 01 Mar 2018 14:43:17 -0500 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 872A94E4C5 for ; Thu, 1 Mar 2018 19:43:16 +0000 (UTC) Received: from red.redhat.com (ovpn-122-122.rdu2.redhat.com [10.10.122.122]) by smtp.corp.redhat.com (Postfix) with ESMTP id EDEE0620A8; Thu, 1 Mar 2018 19:43:15 +0000 (UTC) From: Eric Blake To: qemu-devel@nongnu.org Date: Thu, 1 Mar 2018 13:42:25 -0600 Message-Id: <20180301194245.29854-11-eblake@redhat.com> In-Reply-To: <20180301194245.29854-1-eblake@redhat.com> References: <20180301194245.29854-1-eblake@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.38]); Thu, 01 Mar 2018 19:43:16 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PULL 10/30] qapi: Touch generated files only when they change X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Markus Armbruster Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" From: Markus Armbruster A massive number of objects depends on QAPI-generated headers. In my "build everything" tree, it's roughly 4800 out of 5100. This is particularly annoying when only some of the generated files change, say for a doc fix. Improve qapi-gen.py to touch its output files only if they actually change. Rebuild time for a QAPI doc fix drops from many minutes to a few seconds. Rebuilds get faster for certain code changes, too. For instance, adding a simple QMP event now recompiles less than 200 instead of 4800 objects. But adding a QAPI type is as bad as ever; we've clearly got more work to do. Signed-off-by: Markus Armbruster Reviewed-by: Eric Blake Message-Id: <20180211093607.27351-11-armbru@redhat.com> Reviewed-by: Michael Roth [eblake: fix octal constant for python3] Signed-off-by: Eric Blake --- scripts/qapi/common.py | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/scripts/qapi/common.py b/scripts/qapi/common.py index c3ae590202a..47673928dcc 100644 --- a/scripts/qapi/common.py +++ b/scripts/qapi/common.py @@ -1951,9 +1951,16 @@ class QAPIGen(object): except os.error as e: if e.errno !=3D errno.EEXIST: raise - f =3D open(os.path.join(output_dir, fname), 'w') - f.write(self._top(fname) + self._preamble + self._body + fd =3D os.open(os.path.join(output_dir, fname), + os.O_RDWR | os.O_CREAT, 0o666) + f =3D os.fdopen(fd, 'r+') + text =3D (self._top(fname) + self._preamble + self._body + self._bottom(fname)) + oldtext =3D f.read(len(text) + 1) + if text !=3D oldtext: + f.seek(0) + f.truncate(0) + f.write(text) f.close() --=20 2.14.3