From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A90CEC4361B for ; Thu, 17 Dec 2020 02:18:21 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id E3CF223718 for ; Thu, 17 Dec 2020 02:18:20 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E3CF223718 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:55498 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kpis0-0002yr-0N for qemu-devel@archiver.kernel.org; Wed, 16 Dec 2020 21:18:20 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:53566) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kpia7-0002EV-9c for qemu-devel@nongnu.org; Wed, 16 Dec 2020 20:59:53 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:25017) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1kpiZx-0007Ar-V1 for qemu-devel@nongnu.org; Wed, 16 Dec 2020 20:59:51 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1608170380; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=RPyhPA0LQsrutFNs3gyJCJgOExNTaIdt0Mdj53/n+WU=; b=K0w0VsFMn2HQ8xfbLKoXbgpV/3qBcKwNHIvfPWfDKuNml9dlj6Vnb6gCu77mabzFaclLG7 E8eu2A4Y8HrKlzfbmT/jYJ9vuTyOPEMHDIjLB/NpoJRIEVujOQUhehnzyh1aE6q/hBjpdN Wd90kV/tlDmoM8gQXq9Ef/IxqjuQdyc= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-256-Jx4Vl1LSOT2kHtTVjWQq6w-1; Wed, 16 Dec 2020 20:59:38 -0500 X-MC-Unique: Jx4Vl1LSOT2kHtTVjWQq6w-1 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 mimecast-mx01.redhat.com (Postfix) with ESMTPS id E8FFC59; Thu, 17 Dec 2020 01:59:37 +0000 (UTC) Received: from scv.redhat.com (ovpn-112-131.rdu2.redhat.com [10.10.112.131]) by smtp.corp.redhat.com (Postfix) with ESMTP id 2F7751E5; Thu, 17 Dec 2020 01:59:37 +0000 (UTC) From: John Snow To: qemu-devel@nongnu.org Subject: [PATCH v2 06/12] qapi/source: Add builtin null-object sentinel Date: Wed, 16 Dec 2020 20:59:21 -0500 Message-Id: <20201217015927.197287-7-jsnow@redhat.com> In-Reply-To: <20201217015927.197287-1-jsnow@redhat.com> References: <20201217015927.197287-1-jsnow@redhat.com> 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=jsnow@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset="US-ASCII" Received-SPF: pass client-ip=63.128.21.124; envelope-from=jsnow@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, 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: Eduardo Habkost , Michael Roth , Markus Armbruster , Cleber Rosa , =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= , John Snow Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" We use None to represent an object that has no source information because it's a builtin. This complicates interface typing, since many interfaces expect that there is an info object available to print errors with. Introduce a special QAPISourceInfo that represents these built-ins so that if an error should so happen to occur relating to one of these builtins that we will be able to print its information, and interface typing becomes simpler: you will always have a source info object. This object will evaluate as False, so "if info" remains a valid idiomatic construct. NB: It was intentional to not allow empty constructors or similar to create "empty" source info objects; callers must explicitly invoke 'builtin()' to pro-actively opt into using the sentinel. This should prevent use-by-accident. Signed-off-by: John Snow --- scripts/qapi/source.py | 20 +++++++++++++++++++- 1 file changed, 19 insertions(+), 1 deletion(-) diff --git a/scripts/qapi/source.py b/scripts/qapi/source.py index d7a79a9b8ae..a049b73b57b 100644 --- a/scripts/qapi/source.py +++ b/scripts/qapi/source.py @@ -11,7 +11,12 @@ import copy import sys -from typing import List, Optional, TypeVar +from typing import ( + List, + Optional, + Type, + TypeVar, +) class QAPISchemaPragma: @@ -41,6 +46,17 @@ def __init__(self, fname: str, line: int, self.defn_meta: Optional[str] = None self.defn_name: Optional[str] = None + @classmethod + def builtin(cls: Type[T]) -> T: + """ + Create an instance corresponding to a built-in definition. + """ + return cls('', -1, None) + + def __bool__(self) -> bool: + # "if info" is false if @info corresponds to a built-in definition. + return bool(self.fname) + def set_defn(self, meta: str, name: str) -> None: self.defn_meta = meta self.defn_name = name @@ -73,4 +89,6 @@ def include_path(self) -> str: return ret def __str__(self) -> str: + if not bool(self): + return '[builtin]' return self.include_path() + self.in_defn() + self.loc() -- 2.26.2