[OE-core] [PATCH] oe.types: give the regex type more sane semantics
Saul Wold
sgw at linux.intel.com
Fri May 18 05:40:58 UTC 2012
On 05/16/2012 04:26 AM, Christopher Larson wrote:
> From: Christopher Larson<chris_larson at mentor.com>
>
> Currently, if a variable is unset or has an empty value, the regex type
> will return a match object which always matches. Not all variable types
> will necessarily have the same behavior for handling defaults. I believe
> that returning a match object which matches nothing when a variable is
> unset is superior to returning one which matches anything, and the user
> can always explicitly request anything via '.*', if that's what they
> want.
>
> This constructs a null pattern object which will never match, and uses
> it when encountering an unset or empty variable (currently, these two
> things are one and the same, as maketype is handling the default. we may
> well want to shift that logic into the individual types, giving them
> more control over default behavior, but currently the behavior is at
> least relatively consistent -- no difference between unset and empty
> variables).
>
> Signed-off-by: Christopher Larson<chris_larson at mentor.com>
> ---
> meta/lib/oe/types.py | 31 +++++++++++++++++++++++++++++++
> 1 files changed, 31 insertions(+), 0 deletions(-)
>
> diff --git a/meta/lib/oe/types.py b/meta/lib/oe/types.py
> index ea31cf4..ea53df9 100644
> --- a/meta/lib/oe/types.py
> +++ b/meta/lib/oe/types.py
> @@ -40,6 +40,31 @@ def choice(value, choices):
> (value, choices))
> return value
>
> +class NoMatch(object):
> + """Stub python regex pattern object which never matches anything"""
> + def findall(self, string, flags=0):
> + return None
> +
> + def finditer(self, string, flags=0):
> + return None
> +
> + def match(self, flags=0):
> + return None
> +
> + def search(self, string, flags=0):
> + return None
> +
> + def split(self, string, maxsplit=0):
> + return None
> +
> + def sub(pattern, repl, string, count=0):
> + return None
> +
> + def subn(pattern, repl, string, count=0):
> + return None
> +
> +NoMatch = NoMatch()
> +
> def regex(value, regexflags=None):
> """OpenEmbedded 'regex' type
>
> @@ -59,6 +84,12 @@ def regex(value, regexflags=None):
> except AttributeError:
> raise ValueError("Invalid regex flag '%s'" % flag)
>
> + if not value:
> + # Let's ensure that the default behavior for an undefined or empty
> + # variable is to match nothing. If the user explicitly wants to match
> + # anything, they can match '.*' instead.
> + return NoMatch
> +
> try:
> return re.compile(value, flagval)
> except re.error, exc:
Merged this series of 3 patches into OE-Core
Thanks
Sau!
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