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Wed, 7 Oct 2020 14:32:09 +0200 (CEST) From: Markus Armbruster To: John Snow Subject: Re: [PATCH v5 30/36] qapi/gen.py: update write() to be more idiomatic References: <20201005195158.2348217-1-jsnow@redhat.com> <20201005195158.2348217-31-jsnow@redhat.com> Date: Wed, 07 Oct 2020 14:32:09 +0200 In-Reply-To: <20201005195158.2348217-31-jsnow@redhat.com> (John Snow's message of "Mon, 5 Oct 2020 15:51:52 -0400") Message-ID: <87wo02b4ja.fsf@dusky.pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.1 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=armbru@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain Received-SPF: pass client-ip=216.205.24.124; envelope-from=armbru@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/10/07 00:54:30 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.742, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: qemu-devel@nongnu.org, Eduardo Habkost , Cleber Rosa Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" John Snow writes: > Make the file handling here just a tiny bit more idiomatic. > (I realize this is heavily subjective.) > > Use exist_ok=True for os.makedirs and remove the exception, > use fdopen() to wrap the file descriptor in a File-like object, > and use a context manager for managing the file pointer. > > Signed-off-by: John Snow > Reviewed-by: Eduardo Habkost > Reviewed-by: Cleber Rosa > --- > scripts/qapi/gen.py | 25 +++++++++++-------------- > 1 file changed, 11 insertions(+), 14 deletions(-) > > diff --git a/scripts/qapi/gen.py b/scripts/qapi/gen.py > index 3624162bb77..579ee283297 100644 > --- a/scripts/qapi/gen.py > +++ b/scripts/qapi/gen.py > @@ -14,7 +14,6 @@ > # See the COPYING file in the top-level directory. > > from contextlib import contextmanager > -import errno > import os > import re > from typing import ( > @@ -67,21 +66,19 @@ def write(self, output_dir: str) -> None: > return > pathname = os.path.join(output_dir, self.fname) > odir = os.path.dirname(pathname) > + > if odir: > - try: > - os.makedirs(odir) > - except os.error as e: > - if e.errno != errno.EEXIST: > - raise > + os.makedirs(odir, exist_ok=True) I wouldn't call this part "heavily subjective". When wrote the old code, exist_ok was still off limits (it's new in 3.2). > + > + # use os.open for O_CREAT to create and read a non-existant file > fd = os.open(pathname, os.O_RDWR | os.O_CREAT, 0o666) > - f = open(fd, 'r+', encoding='utf-8') > - text = self.get_content() > - oldtext = f.read(len(text) + 1) > - if text != oldtext: > - f.seek(0) > - f.truncate(0) > - f.write(text) > - f.close() > + with os.fdopen(fd, 'r+', encoding='utf-8') as fp: > + text = self.get_content() > + oldtext = fp.read(len(text) + 1) > + if text != oldtext: > + fp.seek(0) > + fp.truncate(0) > + fp.write(text) > > > def _wrap_ifcond(ifcond: List[str], before: str, after: str) -> str: Reviewed-by: Markus Armbruster