| Message ID | 20201105122808.1182973-10-marcandre.lureau@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | qapi: untie 'if' conditions from C preprocessor | expand |
On 11/5/20 6:28 AM, marcandre.lureau@redhat.com wrote: > From: Marc-André Lureau <marcandre.lureau@redhat.com> > > Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> > --- > docs/devel/qapi-code-gen.txt | 26 +++++++++++++++----------- > 1 file changed, 15 insertions(+), 11 deletions(-) > > diff --git a/docs/devel/qapi-code-gen.txt b/docs/devel/qapi-code-gen.txt > index 3d22a7ae21..c499352a74 100644 > --- a/docs/devel/qapi-code-gen.txt > +++ b/docs/devel/qapi-code-gen.txt > @@ -772,26 +772,30 @@ downstream command __com.redhat_drive-mirror. > === Configuring the schema === > > Syntax: > - COND = STRING > - | [ STRING, ... ] > + COND = CFG-ID > + | [ COND, ... ] As written, you allow recursion of [] such as: [ [ ] ] I think you meant: [ CFG-ID, ...] > + | { 'all: [ COND, ... ] } > + | { 'any: [ COND, ... ] } > + | { 'not': COND } Here, the recursion makes sense: it looks like you want to permit all of these: 'if': { 'not': { 'any': [ 'COND1', 'COND2' ] } } 'if': { 'not': [ 'COND3' ] } 'if': { 'not': 'COND4' } > > -All definitions take an optional 'if' member. Its value must be a > -string or a list of strings. A string is shorthand for a list > -containing just that string. The code generated for the definition > -will then be guarded by #if STRING for each STRING in the COND list. > + CFG-ID = STRING Does CFG-ID need its own rule? Should this rule be listed before COND? > + > +All definitions take an optional 'if' member. Its value must be a string, a list > +of strings or an object with a single member 'all', 'any' or 'not'. A string is > +shorthand for a list containing just that string. A list is a shorthand for a > +'all'-member object. The C code generated for the definition will then be guarded > +by an #if precessor expression. > > Example: a conditional struct > > { 'struct': 'IfStruct', 'data': { 'foo': 'int' }, > - 'if': ['CONFIG_FOO', 'HAVE_BAR'] } > + 'if': { 'all': [ 'CONFIG_FOO', 'HAVE_BAR' ] } } > > gets its generated code guarded like this: > > - #if defined(CONFIG_FOO) > - #if defined(HAVE_BAR) > + #if defined(CONFIG_FOO) && defined(HAVE_BAR) > ... generated code ... > - #endif /* defined(HAVE_BAR) */ > - #endif /* defined(CONFIG_FOO) */ > + #endif /* defined(HAVE_BAR) && defined(CONFIG_FOO) */ > > Individual members of complex types, commands arguments, and > event-specific data can also be made conditional. This requires the > -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3226 Virtualization: qemu.org | libvirt.org
Hi On Thu, Nov 5, 2020 at 5:43 PM Eric Blake <eblake@redhat.com> wrote: > > On 11/5/20 6:28 AM, marcandre.lureau@redhat.com wrote: > > From: Marc-André Lureau <marcandre.lureau@redhat.com> > > > > Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> > > --- > > docs/devel/qapi-code-gen.txt | 26 +++++++++++++++----------- > > 1 file changed, 15 insertions(+), 11 deletions(-) > > > > diff --git a/docs/devel/qapi-code-gen.txt b/docs/devel/qapi-code-gen.txt > > index 3d22a7ae21..c499352a74 100644 > > --- a/docs/devel/qapi-code-gen.txt > > +++ b/docs/devel/qapi-code-gen.txt > > @@ -772,26 +772,30 @@ downstream command __com.redhat_drive-mirror. > > === Configuring the schema === > > > > Syntax: > > - COND = STRING > > - | [ STRING, ... ] > > + COND = CFG-ID > > + | [ COND, ... ] > > As written, you allow recursion of [] such as: > > [ [ ] ] > > I think you meant: [ CFG-ID, ...] It's not just a CFG-ID list that is accepted though. [ {"not": COND1}, COND2 ] is accepted, and should mean All(Not(COND1), COND2). I am not sure how to improve the documentation to really mean non-empty list though. > > > > + | { 'all: [ COND, ... ] } > > + | { 'any: [ COND, ... ] } > > + | { 'not': COND } > > Here, the recursion makes sense: it looks like you want to permit all of > these: > > 'if': { 'not': { 'any': [ 'COND1', 'COND2' ] } } > 'if': { 'not': [ 'COND3' ] } > 'if': { 'not': 'COND4' } > right > > > > -All definitions take an optional 'if' member. Its value must be a > > -string or a list of strings. A string is shorthand for a list > > -containing just that string. The code generated for the definition > > -will then be guarded by #if STRING for each STRING in the COND list. > > + CFG-ID = STRING > > Does CFG-ID need its own rule? Should this rule be listed before COND? We have a couple of prior documentation with forward references like this (ENUM-VALUE, MEMBER, BRANCH, ALTERNATIVE, FEATURE..) > > > + > > +All definitions take an optional 'if' member. Its value must be a string, a list > > +of strings or an object with a single member 'all', 'any' or 'not'. A string is > > +shorthand for a list containing just that string. A list is a shorthand for a > > +'all'-member object. The C code generated for the definition will then be guarded > > +by an #if precessor expression. > > > > Example: a conditional struct > > > > { 'struct': 'IfStruct', 'data': { 'foo': 'int' }, > > - 'if': ['CONFIG_FOO', 'HAVE_BAR'] } > > + 'if': { 'all': [ 'CONFIG_FOO', 'HAVE_BAR' ] } } > > > > gets its generated code guarded like this: > > > > - #if defined(CONFIG_FOO) > > - #if defined(HAVE_BAR) > > + #if defined(CONFIG_FOO) && defined(HAVE_BAR) > > ... generated code ... > > - #endif /* defined(HAVE_BAR) */ > > - #endif /* defined(CONFIG_FOO) */ > > + #endif /* defined(HAVE_BAR) && defined(CONFIG_FOO) */ > > > > Individual members of complex types, commands arguments, and > > event-specific data can also be made conditional. This requires the > > > > -- > Eric Blake, Principal Software Engineer > Red Hat, Inc. +1-919-301-3226 > Virtualization: qemu.org | libvirt.org > thanks
diff --git a/docs/devel/qapi-code-gen.txt b/docs/devel/qapi-code-gen.txt index 3d22a7ae21..c499352a74 100644 --- a/docs/devel/qapi-code-gen.txt +++ b/docs/devel/qapi-code-gen.txt @@ -772,26 +772,30 @@ downstream command __com.redhat_drive-mirror. === Configuring the schema === Syntax: - COND = STRING - | [ STRING, ... ] + COND = CFG-ID + | [ COND, ... ] + | { 'all: [ COND, ... ] } + | { 'any: [ COND, ... ] } + | { 'not': COND } -All definitions take an optional 'if' member. Its value must be a -string or a list of strings. A string is shorthand for a list -containing just that string. The code generated for the definition -will then be guarded by #if STRING for each STRING in the COND list. + CFG-ID = STRING + +All definitions take an optional 'if' member. Its value must be a string, a list +of strings or an object with a single member 'all', 'any' or 'not'. A string is +shorthand for a list containing just that string. A list is a shorthand for a +'all'-member object. The C code generated for the definition will then be guarded +by an #if precessor expression. Example: a conditional struct { 'struct': 'IfStruct', 'data': { 'foo': 'int' }, - 'if': ['CONFIG_FOO', 'HAVE_BAR'] } + 'if': { 'all': [ 'CONFIG_FOO', 'HAVE_BAR' ] } } gets its generated code guarded like this: - #if defined(CONFIG_FOO) - #if defined(HAVE_BAR) + #if defined(CONFIG_FOO) && defined(HAVE_BAR) ... generated code ... - #endif /* defined(HAVE_BAR) */ - #endif /* defined(CONFIG_FOO) */ + #endif /* defined(HAVE_BAR) && defined(CONFIG_FOO) */ Individual members of complex types, commands arguments, and event-specific data can also be made conditional. This requires the