From patchwork Thu Jul 29 17:55:53 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eduardo Habkost X-Patchwork-Id: 12409413 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 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 54A58C4338F for ; Thu, 29 Jul 2021 18:05:03 +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 05DA860F4A for ; Thu, 29 Jul 2021 18:05:03 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 05DA860F4A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=nongnu.org Received: from localhost ([::1]:42752 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1m9AP0-0008CG-0z for qemu-devel@archiver.kernel.org; Thu, 29 Jul 2021 14:05:02 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:52510) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1m9AGU-0006nu-3l for qemu-devel@nongnu.org; Thu, 29 Jul 2021 13:56:14 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:24889) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1m9AGS-00080j-B3 for qemu-devel@nongnu.org; Thu, 29 Jul 2021 13:56:13 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1627581371; 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=PFauT1gi4Um7HvJ1OXpmVPNsZptBn73opwaZb9cI1hE=; b=NGG1+kDbmM23L1UEH7lPIKI1zp81X5VKT/p+AIDhkDcYdDjnqPLpJUyIGvZccVhXB58DLI pnSR5Ux+S/KWSm0ELVAh6HUBectlYyftabJvfiQuLabGBwT2GUQojryCb45tS2WRC1q83g sEcvYhg/QtGde/okSJtI1xLlu22V/KA= 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-544-sOrFrnvOOZS8gpLSfk_KoQ-1; Thu, 29 Jul 2021 13:56:10 -0400 X-MC-Unique: sOrFrnvOOZS8gpLSfk_KoQ-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 730861006C85 for ; Thu, 29 Jul 2021 17:56:09 +0000 (UTC) Received: from localhost (unknown [10.22.18.227]) by smtp.corp.redhat.com (Postfix) with ESMTP id 2F65D60BF1; Thu, 29 Jul 2021 17:56:09 +0000 (UTC) From: Eduardo Habkost To: qemu-devel@nongnu.org Subject: [PATCH for-6.2 09/10] docs: qom: Remove OBJECT_CHECK macro examples Date: Thu, 29 Jul 2021 13:55:53 -0400 Message-Id: <20210729175554.686474-10-ehabkost@redhat.com> In-Reply-To: <20210729175554.686474-1-ehabkost@redhat.com> References: <20210729175554.686474-1-ehabkost@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=ehabkost@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=170.10.133.124; envelope-from=ehabkost@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -34 X-Spam_score: -3.5 X-Spam_bar: --- X-Spam_report: (-3.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.717, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, 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: Paolo Bonzini , =?utf-8?q?Daniel_P=2E_Berrang=C3=A9?= , Eduardo Habkost Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" We shouldn't encourage people to keep defining typecast macros manually, when we have the OBJECT_DECLARE* macros. Remove the section showing how to define them, and replace with a section explaining how typecasting works. Signed-off-by: Eduardo Habkost Reviewed-by: Peter Maydell --- docs/devel/qom.rst | 46 +++++++++++++++++++++++++++++++--------------- 1 file changed, 31 insertions(+), 15 deletions(-) diff --git a/docs/devel/qom.rst b/docs/devel/qom.rst index 3ae6f75a1a2..0f222555019 100644 --- a/docs/devel/qom.rst +++ b/docs/devel/qom.rst @@ -69,21 +69,10 @@ are instantiated dynamically but there is only ever one instance for any given type. The `ObjectClass` typically holds a table of function pointers for the virtual methods implemented by this type. -Using `object_new()`, a new `Object` derivative will be instantiated. You can -cast an `Object` to a subclass (or base-class) type using -`object_dynamic_cast()`. You typically want to define macro wrappers around -`OBJECT_CHECK()` and `OBJECT_CLASS_CHECK()` to make it easier to convert to a -specific type: - -.. code-block:: c - :caption: Typecasting macros - - #define MY_DEVICE_GET_CLASS(obj) \ - OBJECT_GET_CLASS(MyDeviceClass, obj, TYPE_MY_DEVICE) - #define MY_DEVICE_CLASS(klass) \ - OBJECT_CLASS_CHECK(MyDeviceClass, klass, TYPE_MY_DEVICE) - #define MY_DEVICE(obj) \ - OBJECT_CHECK(MyDevice, obj, TYPE_MY_DEVICE) +Using `object_new()`, a new `Object` derivative will be +instantiated. You can cast an `Object` to a subclass (or +base-class) type using `object_dynamic_cast()` or :ref:`typecast +wrappers `. In case the ObjectClass implementation can be built as module a module_obj() line must be added to make sure qemu loads the module @@ -93,6 +82,31 @@ when the object is needed. module_obj(TYPE_MY_DEVICE); +.. _typecasting: + +Typecasting +=========== + +The `OBJECT_DECLARE macros ` automatically define +typecasting functions having signatures like these: + +.. code-block:: c + + static inline MyDevice *MY_DEVICE(const void *obj); + static inline MyDeviceClass *MY_DEVICE_GET_CLASS(const void *obj); + static inline MyDeviceClass *MY_DEVICE_CLASS(const void *klass); + +These typecasting functions are wrappers around `OBJECT_CHECK`, +`OBJECT_GET_CLASS`, and `OBJECT_CLASS_CHECK`. Example usage: + +.. code-block:: c + + Object *obj = object_new("my-device"); + MyDevice *my_dev = MY_DEVICE(obj); + DeviceState *dev = DEVICE(my_dev); + MyDeviceClass *mdc = MY_DEVICE_GET_CLASS(my_dev); + DeviceClass *dc = DEVICE_CLASS(mdc); + Class Initialization ==================== @@ -282,6 +296,8 @@ convention. To reduce the amount of boilerplate code that needs to be written for a new type there are two sets of macros to generate the common parts in a standard format. +.. _OBJECT_DECLARE: + Type declaration macros -----------------------