Re: [PATCH 4/4] pylibfdt: add FdtRo.getprop_or_none()

[David Gibson <david-xT8FGy+AXnRB3Ne2BGzF6laj5H9X9Tb+@public.gmane.org>]

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On Sat, Dec 25, 2021 at 02:25:58PM +0100, Luca Weiss wrote:
> Add a new method that doesn't throw an exception when a property isn't
> found but returns None instead.
> 
> Also add a test for the new method.
> 
> Signed-off-by: Luca Weiss <luca-IfPCFPJWly+lVyrhU4qvOw@public.gmane.org>

I'd need a stronger rationale to apply this.  It's not really doing
anything that the existing getprop method can't, just presenting it in
a slightly different form.

> ---
>  pylibfdt/libfdt.i       | 10 ++++++++++
>  tests/pylibfdt_tests.py |  2 ++
>  2 files changed, 12 insertions(+)
> 
> diff --git a/pylibfdt/libfdt.i b/pylibfdt/libfdt.i
> index 5434d48..2c2fa5c 100644
> --- a/pylibfdt/libfdt.i
> +++ b/pylibfdt/libfdt.i
> @@ -419,6 +419,16 @@ class FdtRo(object):
>              return pdata
>          return Property(prop_name, bytearray(pdata[0]))
>  
> +    def getprop_or_none(self, nodeoffset, prop_name):
> +        """Get a property from a node, or None if it is not found
> +
> +        See getprop() for the arguments.
> +        """
> +        prop = self.getprop(nodeoffset, prop_name, [FDT_ERR_NOTFOUND])
> +        if prop == -FDT_ERR_NOTFOUND:
> +            return None
> +        return prop
> +
>      def get_phandle(self, nodeoffset):
>          """Get the phandle of a node
>  
> diff --git a/tests/pylibfdt_tests.py b/tests/pylibfdt_tests.py
> index bcd3daa..152e925 100644
> --- a/tests/pylibfdt_tests.py
> +++ b/tests/pylibfdt_tests.py
> @@ -219,6 +219,8 @@ class PyLibfdtBasicTests(unittest.TestCase):
>              self.fdt.getprop(root, 'missing')
>          self.assertEqual(e.exception.err, -libfdt.NOTFOUND)
>  
> +        self.assertIsNone(self.fdt.getprop_or_none(root, 'missing'))
> +
>          node = self.fdt.path_offset('/subnode@1/subsubnode')
>          value = self.fdt.getprop(node, "compatible")
>          self.assertEqual(value, b'subsubnode1\0subsubnode\0')

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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