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=-13.5 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 6D7EFC2BB40 for ; Mon, 14 Dec 2020 23:57:09 +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 1F14920732 for ; Mon, 14 Dec 2020 23:57:09 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1F14920732 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]:39408 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1koxiG-000893-42 for qemu-devel@archiver.kernel.org; Mon, 14 Dec 2020 18:57:08 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:43692) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1koxf4-0003Hj-0s for qemu-devel@nongnu.org; Mon, 14 Dec 2020 18:53:50 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:26384) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1koxf2-0000tm-97 for qemu-devel@nongnu.org; Mon, 14 Dec 2020 18:53:49 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1607990027; 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=yVunUmIG6winirkBVZemtaF3IjSeIhFGCw8J53mrOFg=; b=AAmBz/K8z79r8mm9NZB4UXSws4NCqs8CFaI9zAuuDCaFMZQ+kvJk/MgIY7LkGt/Ns7wcuJ +jNU9ir7yJCaIPoa/6QJaBGfrrzxq1RIrGFMLuZsMDN4uSjeqcPNv/OWYUuJuNXwk313c4 131xFI77sXeoEWecuVgeDPW8XO7mQm4= 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-550-9c5lhPtQOGqSjwBzM9J5MQ-1; Mon, 14 Dec 2020 18:53:45 -0500 X-MC-Unique: 9c5lhPtQOGqSjwBzM9J5MQ-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 0201F59 for ; Mon, 14 Dec 2020 23:53:45 +0000 (UTC) Received: from scv.redhat.com (ovpn-116-117.rdu2.redhat.com [10.10.116.117]) by smtp.corp.redhat.com (Postfix) with ESMTP id 43F3F13470; Mon, 14 Dec 2020 23:53:44 +0000 (UTC) From: John Snow To: qemu-devel@nongnu.org Subject: [PATCH 06/12] qapi/source: Add builtin null-object sentinel Date: Mon, 14 Dec 2020 18:53:21 -0500 Message-Id: <20201214235327.1007124-7-jsnow@redhat.com> In-Reply-To: <20201214235327.1007124-1-jsnow@redhat.com> References: <20201214235327.1007124-1-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: =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= , Cleber Rosa , John Snow , Eduardo Habkost , Markus Armbruster 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" is 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 d7a79a9b8aee..64af7318cb67 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 a SourceInfo object corresponding to a builtin definition. + """ + return cls('', -1, None) + + def __bool__(self) -> bool: + # "if info: ..." is false if info is the builtin sentinel. + 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