[Qemu-devel] New Bee : What is the canonical path.

[Qemu-devel] New Bee : What is the canonical path.

[boddu pavan]

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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.
Thanks,Sai Pavan

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Re: [Qemu-devel] New Bee : What is the canonical path.

[Paolo Bonzini]

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

Re: [Qemu-devel] New Bee : What is the canonical path.

[boddu pavan]

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Thanks Poalo, This was helpful.
Regards,Sai Pavan 

     On Wednesday, December 10, 2014 6:27 PM, Paolo Bonzini <pbonzini@redhat.com> wrote:
   

 

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



   

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