On Thu, Feb 18, 2016 at 08:26:44AM +0100, Markus Armbruster wrote:
> Peter Xu <pet...@redhat.com> writes:
>
> > Changes from v7:
> > - patch 8: use s->dump_info.page_size not TARGET_PAGE_SIZE
> > - patch 10: change DUMP_STATUS_MAX to DUMP_STATUS__MAX (this is to
> > fix compile error for rebasing to latest master branch, still do
> > not know why we need this change from generating "_MAX" to
> > "__MAX" for enum types...)
>
> Don't ask yourself why something was done, ask git :)
Sorry for my laziness... But it seems that it luckily brings me
another "-S" git trick. Lots of things to learn. :-)
>
> $ git-log -S__MAX
> [...]
> commit 7fb1cf1606c78c9d5b538f29176fd5a101726a9d
> Author: Eric Blake <ebl...@redhat.com>
> Date: Wed Nov 18 01:52:57 2015 -0700
>
> ---> qapi: Don't let implicit enum MAX member collide
>
> Now that we guarantee the user doesn't have any enum values
> beginning with a single underscore, we can use that for our
> own purposes. Renaming ENUM_MAX to ENUM__MAX makes it obvious
> that the sentinel is generated.
>
> This patch was mostly generated by applying a temporary patch:
>
> |diff --git a/scripts/qapi.py b/scripts/qapi.py
> |index e6d014b..b862ec9 100644
> |--- a/scripts/qapi.py
> |+++ b/scripts/qapi.py
> |@@ -1570,6 +1570,7 @@ const char *const %(c_name)s_lookup[] = {
> | max_index = c_enum_const(name, 'MAX', prefix)
> | ret += mcgen('''
> | [%(max_index)s] = NULL,
> |+// %(max_index)s
> | };
> | ''',
> | max_index=max_index)
>
> then running:
>
> $ cat qapi-{types,event}.c tests/test-qapi-types.c |
> sed -n 's,^// \(.*\)MAX,s|\1MAX|\1_MAX|g,p' > list
> $ git grep -l _MAX | xargs sed -i -f list
>
> The only things not generated are the changes in scripts/qapi.py.
>
> Rejecting enum members named 'MAX' is now useless, and will be dropped
> in the next patch.
>
> Signed-off-by: Eric Blake <ebl...@redhat.com>
> Message-Id: <1447836791-369-23-git-send-email-ebl...@redhat.com>
> Reviewed-by: Juan Quintela <quint...@redhat.com>
> [Rebased to current master, commit message tweaked]
> Signed-off-by: Markus Armbruster <arm...@redhat.com>
>
> I guess this isn't perfectly clear without more context, so let me add
> some.
>
> The implicit FOO_MAX could collide with the user's FOO_MAX for QAPI
> enumeration values 'max', or case variations thereof. Commit cf39359
> added extra code to catch that.
>
> Renaming the implict FOO_MAX to FOO__MAX removes the need for the
> special rule "you can't use 'max' as an enumeration value", because the
> general rule "names starting with '_' are reserved" suffices then.
>
> Fewer rules is better.
Yah. The commit is reasonable and explanation is clear. Thanks!
Peter
>
> [...]
