From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from eggs.gnu.org ([2001:4830:134:3::10]:47380)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <paolo.bonzini@gmail.com>) id 1XyfAs-0002iH-1J
	for qemu-devel@nongnu.org; Wed, 10 Dec 2014 06:11:27 -0500
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <paolo.bonzini@gmail.com>) id 1XyfAi-00071f-UE
	for qemu-devel@nongnu.org; Wed, 10 Dec 2014 06:11:17 -0500
Received: from mail-wi0-x231.google.com ([2a00:1450:400c:c05::231]:32816)
	by eggs.gnu.org with esmtp (Exim 4.71)
	(envelope-from <paolo.bonzini@gmail.com>) id 1XyfAi-00071b-Mf
	for qemu-devel@nongnu.org; Wed, 10 Dec 2014 06:11:08 -0500
Received: by mail-wi0-f177.google.com with SMTP id l15so4720617wiw.16
	for <qemu-devel@nongnu.org>; Wed, 10 Dec 2014 03:11:08 -0800 (PST)
Sender: Paolo Bonzini <paolo.bonzini@gmail.com>
Message-ID: <54882A43.2030607@redhat.com>
Date: Wed, 10 Dec 2014 12:10:59 +0100
From: Paolo Bonzini <pbonzini@redhat.com>
MIME-Version: 1.0
References: <522493776.4407770.1418124502655.JavaMail.yahoo@jws100120.mail.ne1.yahoo.com>
In-Reply-To: <522493776.4407770.1418124502655.JavaMail.yahoo@jws100120.mail.ne1.yahoo.com>
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 7bit
Subject: Re: [Qemu-devel] New Bee : What is the canonical path.
List-Id: <qemu-devel.nongnu.org>
List-Unsubscribe: <https://lists.nongnu.org/mailman/options/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.nongnu.org/archive/html/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <https://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: boddu pavan <boddupavan@yahoo.com>, QEMU Developers <qemu-devel@nongnu.org>



On 09/12/2014 12:28, boddu pavan wrote:
> Hi, 
> 
> I am new to qemu, And i need help in understanding a part of code,  Can
> any one tell the use of Canonical paths of the Object.

The use is mostly internal.  Every time you set a property, you go
through a "Visitor" that represents the value.  The representations
allowed by visitors are numbers, strings, booleans, etc.

When you want to set a property to an object, you actually need to set a
property to a string, because Visitors support string values.  So you
use a "path".  Typically you'll use a canonical path (though you can
also use a non-canonical path).  Canonical paths are formed by following
properties of type child<Something>.  Non-canonical paths are formed by
following properties of type child<Something> or link<Something> (where
Something is the name of a class type).

Similarly, when you read a property that has an object type, the
property's value will be a path, and the getter for that property will
always use a canonical path.

Paolo