[Mesa-dev] [PATCH 21/26] python: Use key-functions when sorting containers

[Eric Engestrom]

On Thursday, 2018-07-05 09:38:19 -0700, Dylan Baker wrote:
> Quoting Mathieu Bridon (2018-07-05 06:17:52)
> > In Python 2, the traditional way to sort containers was to use a
> > comparison function (which returned either -1, 0 or 1 when passed two
> > objects) and pass that as the "cmp" argument to the container's sort()
> > method.
> > 
> > Python 2.4 introduced key-functions, which instead only operate on a
> > given item, and return a sorting key for this item.
> > 
> > In general, this runs faster, because the cmp-function has to get run
> > multiple times for each item of the container.
> > 
> > Python 3 removed the cmp-function, enforcing usage of key-functions
> > instead.
> > 
> > This change makes the script compatible with Python 2 and Python 3.
> > 
> > Signed-off-by: Mathieu Bridon <bochecha at daitauha.fr>
> > ---
> >  src/mapi/mapi_abi.py | 5 +++--
> >  1 file changed, 3 insertions(+), 2 deletions(-)
> > 
> > diff --git a/src/mapi/mapi_abi.py b/src/mapi/mapi_abi.py
> > index 67fdb10650..19fdc4572a 100644
> > --- a/src/mapi/mapi_abi.py
> > +++ b/src/mapi/mapi_abi.py
> > @@ -32,6 +32,7 @@ import os
> >  GLAPI = os.path.join(".", os.path.dirname(sys.argv[0]), "glapi/gen")
> >  sys.path.append(GLAPI)
> >  
> > +from operator import attrgetter
> >  import re
> >  from optparse import OptionParser
> >  import gl_XML
> > @@ -305,7 +306,7 @@ class ABIPrinter(object):
> >  
> >          # sort entries by their names
> >          self.entries_sorted_by_names = self.entries[:]
> > -        self.entries_sorted_by_names.sort(lambda x, y: cmp(x.name, y.name))
> > +        self.entries_sorted_by_names.sort(key=attrgetter('name'))
> 
> how about:
> self.entries_sorted_by_names = list(sorted(self.entries, key=attrgetter('name')))
> 
> To avoid the copy and in-place sort.

Good idea; with that:
Reviewed-by: Eric Engestrom <eric.engestrom at intel.com>

> 
> >  
> >          self.indent = ' ' * 3
> >          self.noop_warn = 'noop_warn'
> > @@ -455,7 +456,7 @@ class ABIPrinter(object):
> >          """Return the string pool for use by stubs."""
> >          # sort entries by their names
> >          sorted_entries = self.entries[:]
> > -        sorted_entries.sort(lambda x, y: cmp(x.name, y.name))
> > +        sorted_entries.sort(key=attrgetter('name'))
> >  
> >          pool = []
> >          offsets = {}
> > -- 
> > 2.17.1
> > 
> > _______________________________________________
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> > mesa-dev at lists.freedesktop.org
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