Em Fri, 04 Jul 2025 08:59:45 -0600 Jonathan Corbet <corbet@xxxxxxx> escreveu: > Mauro Carvalho Chehab <mchehab+huawei@xxxxxxxxxx> writes: > > > Em Thu, 03 Jul 2025 17:47:13 -0600 > > Jonathan Corbet <corbet@xxxxxxx> escreveu: > > > >> Mauro Carvalho Chehab <mchehab+huawei@xxxxxxxxxx> writes: > >> > >> > Em Thu, 3 Jul 2025 12:43:58 -0600 > >> > Jonathan Corbet <corbet@xxxxxxx> escreveu: > >> > > >> >> Rework _add_regex() to avoid doing the lookup twice for the (hopefully > >> >> common) cache-hit case. > >> >> > >> >> Signed-off-by: Jonathan Corbet <corbet@xxxxxxx> > >> >> --- > >> >> scripts/lib/kdoc/kdoc_re.py | 7 ++----- > >> >> 1 file changed, 2 insertions(+), 5 deletions(-) > >> >> > >> >> diff --git a/scripts/lib/kdoc/kdoc_re.py b/scripts/lib/kdoc/kdoc_re.py > >> >> index e81695b273bf..612223e1e723 100644 > >> >> --- a/scripts/lib/kdoc/kdoc_re.py > >> >> +++ b/scripts/lib/kdoc/kdoc_re.py > >> >> @@ -29,12 +29,9 @@ class KernRe: > >> >> """ > >> >> Adds a new regex or re-use it from the cache. > >> >> """ > >> >> - > >> >> - if string in re_cache: > >> >> - self.regex = re_cache[string] > >> >> - else: > >> >> + self.regex = re_cache.get(string, None) > >> > > >> > With get, None is default... > >> > > >> >> + if not self.regex: > >> >> self.regex = re.compile(string, flags=flags) > >> > > >> > ... yet, as you're using get, better to code it as: > >> > > >> > self.regex = re_cache.get(string, re.compile(string, flags=flags)) > >> > >> ...but that will recompile the regex each time, defeating the purpose of > >> the cache, no? > > > > No. It should do exactly like the previous code: > > > > - if re_cache[string] exists, it returns it. > > - Otherwise, it returns re.compile(string, flags=flags). > > > > https://www.w3schools.com/python/ref_dictionary_get.asp > > The re.compile() call is evaluated before the call to get() - just like > it would be in C. This is easy enough to prove to yourself in the REPL > if you doubt me... You're right! Tested with the small code snippet: # test.py inner called Inner will be called: True inner called Inner should not be called: False I guess I expected too much from python's optimizer ;-) My fault. Your patch looks OK to me. Reviewed-by: Mauro Carvalho Chehab <mchehab+huawei@xxxxxxxxxx> - As reference, this was the test code #!/usr/bin/env python3 def inner(): print("inner called") return True c = {} print(f"Inner will be called: {c.get('a', inner())}") c = { "a": "False"} print(f"Inner should not be called: {c.get('a', inner())}") Thanks, Mauro
