On 4/29/21 9:40 AM, marcandre.lureau@redhat.com wrote:
> From: Marc-André Lureau <marcandre.lureau@redhat.com>
>
> The following patches are going to express schema 'if' conditions in a
> target language agnostic way. For that, let's start building a predicate
> tree of the configuration options.
>
> This intermediary steps still uses C-preprocessor expressions as
> the predicates:
>
> "if: [STR, ..]" is translated to a "IfCond -> IfAll ->
> [IfOption, ..]" tree, which will generate "#if STR && .." C code.
>
> Once the boolean operation tree nodes are introduced, the 'if'
> expressions will be converted to replace the C syntax (no more
> !defined(), &&, ...) and based only on option identifiers.
>
> For now, the condition tree will be less expressive than a full C macro
> _expression_ as it will only support these operations: 'all', 'any' and
> 'not', the only ones needed so far.
>
> Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
> ---
> docs/sphinx/qapidoc.py | 6 +--
> scripts/qapi/common.py | 54 +++++++++++++++++++++++-
> scripts/qapi/schema.py | 42 ++++++++++++-------
> tests/qapi-schema/doc-good.out | 12 +++---
> tests/qapi-schema/qapi-schema-test.out | 58 +++++++++++++-------------
> 5 files changed, 116 insertions(+), 56 deletions(-)
>
> diff --git a/docs/sphinx/qapidoc.py b/docs/sphinx/qapidoc.py
> index b737949007..a93f3f1c4d 100644
> --- a/docs/sphinx/qapidoc.py
> +++ b/docs/sphinx/qapidoc.py
> @@ -112,12 +112,10 @@ def _make_section(self, title):
> def _nodes_for_ifcond(self, ifcond, with_if=True):
> """Return list of Text, literal nodes for the ifcond
>
> - Return a list which gives text like ' (If: cond1, cond2, cond3)', where
> - the conditions are in literal-text and the commas are not.
> + Return a list which gives text like ' (If: condition)'.
> If with_if is False, we don't return the "(If: " and ")".
> """
> - condlist = intersperse([nodes.literal('', c) for c in ifcond.ifcond],
> - nodes.Text(', '))
was this the last user of intersperse?
mm, no, there's one more.
> + condlist = [nodes.literal('', ifcond.gen_doc())]
> if not with_if:
> return condlist
>
> diff --git a/scripts/qapi/common.py b/scripts/qapi/common.py
> index b7f475a160..59a7ee2f32 100644
> --- a/scripts/qapi/common.py
> +++ b/scripts/qapi/common.py
> @@ -11,8 +11,9 @@
> # This work is licensed under the terms of the GNU GPL, version 2.
> # See the COPYING file in the top-level directory.
>
> +from abc import ABC, abstractmethod
> import re
> -from typing import Optional
> +from typing import Optional, Sequence
>
>
> #: Magic string that gets removed along with all space to its right.
> @@ -192,3 +193,54 @@ def guardend(name: str) -> str:
> #endif /* %(name)s */
> ''',
> name=c_fname(name).upper())
> +
> +
> +class IfPredicate(ABC):
> + @abstractmethod
> + def cgen(self) -> str:
Like the review to patch 2, I'm not sure we want to bake cgen stuff
directly into this class. Are you going to have cgen() and rustgen()
methods all here?
As discussed, we'll see that when we get to it, I don't remember.
> + pass
> +
I think you want raise NotImplementedError to specify a function that
the inheriting class MUST implement. Otherwise, there's little value to
allow a child class to call super() on a method that doesn't have a
default implementation.
You *could* drop the (ABC) and the @abstractmethod decorators if you do so.
Matters of taste and style.
ok
> + @abstractmethod
> + def docgen(self) -> str:
> + pass
> + > +
> +class IfOption(IfPredicate):
missing a docstring here, but I suppose I haven't written a style guide
on how to write those yet.
I assume IfOption is one single element?
e.g. X && Y && Z is
All(
Option(X),
Option(Y),
Option(Z),
)
Right?
Correct
> + def __init__(self, option: str):
> + self.option = option
> +
> + def cgen(self) -> str:
> + return self.option
> +
> + def docgen(self) -> str:
> + return self.option
> +
> + def __repr__(self) -> str:
> + return repr(self.option)
> +
type(self).__name__ + f"({self.option!r})"
or just hard-code the IfOption in there
ok
> + def __eq__(self, other: object) -> bool:
> + if not isinstance(other, IfOption):
> + return False
maybe NotImplemented?
(Admitting I don't know the FULL consequences of doing it either way,
just prompting you for an explanation.)
Apparently NotImplemented is the best thing to do, as it will fallback in other ways.
It doesn't really matter it seems, let's use NotImplemented.
> + return self.option == other.option
> +
> +
> +class IfAll(IfPredicate):
> + def __init__(self, pred_list: Sequence[IfPredicate]):
> + self.pred_list = pred_list
> +
> + def cgen(self) -> str:
> + return " && ".join([p.cgen() for p in self.pred_list])
> +
> + def docgen(self) -> str:
> + return " and ".join([p.docgen() for p in self.pred_list])
> +
> + def __bool__(self) -> bool:
> + return bool(self.pred_list)
> +
> + def __repr__(self) -> str:
> + return f"IfAll({self.pred_list})"
> +
{self.pred_list!r} to get the recursive repr.
ok
You can consider adding a __str__ method to add a kind of short-hand
that skips the class names and stuff and keeps the output less chatty.
ok
> + def __eq__(self, other: object) -> bool:
> + if not isinstance(other, IfAll):
> + return False
NotImplemented again?
> + return self.pred_list == other.pred_list
> diff --git a/scripts/qapi/schema.py b/scripts/qapi/schema.py
> index 8e6d0a5296..366a53ab64 100644
> --- a/scripts/qapi/schema.py
> +++ b/scripts/qapi/schema.py
> @@ -19,7 +19,13 @@
> import re
> from typing import Optional
>
> -from .common import POINTER_SUFFIX, c_name, mcgen
> +from .common import (
> + POINTER_SUFFIX,
> + IfAll,
> + IfOption,
> + c_name,
> + mcgen,
> +)
> from .error import QAPISemError, QAPISourceError
> from .expr import check_exprs
> from .parser import QAPISchemaParser
> @@ -27,34 +33,38 @@
>
> class QAPISchemaIfCond:
> def __init__(self, ifcond=None):
> - self.ifcond = ifcond or []
> + pred_list = [IfOption(opt) for opt in ifcond or []]
> + self.pred = IfAll(pred_list)
> +
> + def gen_doc(self):
> + if self.pred:
> + return self.pred.docgen()
> + return ""
>
pred should always be IfAll as of here, can we remove the conditional?
.join() will deform to the empty string when it's given an empty sequence
ok
> def gen_if(self):
> - ret = ''
> - for ifc in self.ifcond:
> - ret += mcgen('''
> + if self.pred:
> + return mcgen('''
> #if %(cond)s
> -''', cond=ifc)
> - return ret
> +''', cond=self.pred.cgen())
> + return ""
>
> def gen_endif(self):
> - ret = ''
> - for ifc in reversed(self.ifcond):
> - ret += mcgen('''
> -#endif /* %(cond)s */
> -''', cond=ifc)
> - return ret
> + if self.pred:
> + return mcgen('''
> +#endif // %(cond)s
> +''', cond=self.pred.cgen())
> + return ""
>
> def __bool__(self):
> - return bool(self.ifcond)
> + return bool(self.pred)
>
> def __repr__(self):
> - return repr(self.ifcond)
> + return repr(self.pred)
>
> def __eq__(self, other):
> if not isinstance(other, QAPISchemaIfCond):
> return NotImplemented
> - return self.ifcond == other.ifcond
> + return self.pred == other.pred
>
>
> class QAPISchemaEntity:
> diff --git a/tests/qapi-schema/doc-good.out b/tests/qapi-schema/doc-good.out
> index 8f54ceff2e..6bf996f539 100644
> --- a/tests/qapi-schema/doc-good.out
> +++ b/tests/qapi-schema/doc-good.out
> @@ -12,15 +12,15 @@ enum QType
> module doc-good.json
> enum Enum
> member one
> - if ['defined(IFONE)']
> + if IfAll(['defined(IFONE)'])
I suppose the test output changing, no longer representing a single
language makes sense.
> member two
> - if ['defined(IFCOND)']
> + if IfAll(['defined(IFCOND)'])
> feature enum-feat
> object Base
> member base1: Enum optional=False
> object Variant1
> member var1: str optional=False
> - if ['defined(IFSTR)']
> + if IfAll(['defined(IFSTR)'])
> feature member-feat
> feature variant1-feat
> object Variant2
> @@ -29,7 +29,7 @@ object Object
> tag base1
> case one: Variant1
> case two: Variant2
> - if ['IFTWO']
> + if IfAll(['IFTWO'])
> feature union-feat1
> object q_obj_Variant1-wrapper
> member data: Variant1 optional=False
> @@ -38,13 +38,13 @@ object q_obj_Variant2-wrapper
> enum SugaredUnionKind
> member one
> member two
> - if ['IFTWO']
> + if IfAll(['IFTWO'])
> object SugaredUnion
> member type: SugaredUnionKind optional=False
> tag type
> case one: q_obj_Variant1-wrapper
> case two: q_obj_Variant2-wrapper
> - if ['IFTWO']
> + if IfAll(['IFTWO'])
> feature union-feat2
> alternate Alternate
> tag type
> diff --git a/tests/qapi-schema/qapi-schema-test.out b/tests/qapi-schema/qapi-schema-test.out
> index e0b8a5f0b6..c2d303aa18 100644
> --- a/tests/qapi-schema/qapi-schema-test.out
> +++ b/tests/qapi-schema/qapi-schema-test.out
> @@ -298,65 +298,65 @@ command __org.qemu_x-command q_obj___org.qemu_x-command-arg -> __org.qemu_x-Unio
> object TestIfStruct
> member foo: int optional=False
> member bar: int optional=False
> - if ['defined(TEST_IF_STRUCT_BAR)']
> - if ['defined(TEST_IF_STRUCT)']
> + if IfAll(['defined(TEST_IF_STRUCT_BAR)'])
> + if IfAll(['defined(TEST_IF_STRUCT)'])
> enum TestIfEnum
> member foo
> member bar
> - if ['defined(TEST_IF_ENUM_BAR)']
> - if ['defined(TEST_IF_ENUM)']
> + if IfAll(['defined(TEST_IF_ENUM_BAR)'])
> + if IfAll(['defined(TEST_IF_ENUM)'])
> object q_obj_TestStruct-wrapper
> member data: TestStruct optional=False
> enum TestIfUnionKind
> member foo
> member bar
> - if ['defined(TEST_IF_UNION_BAR)']
> - if ['defined(TEST_IF_UNION) && defined(TEST_IF_STRUCT)']
> + if IfAll(['defined(TEST_IF_UNION_BAR)'])
> + if IfAll(['defined(TEST_IF_UNION) && defined(TEST_IF_STRUCT)'])
> object TestIfUnion
> member type: TestIfUnionKind optional=False
> tag type
> case foo: q_obj_TestStruct-wrapper
> case bar: q_obj_str-wrapper
> - if ['defined(TEST_IF_UNION_BAR)']
> - if ['defined(TEST_IF_UNION) && defined(TEST_IF_STRUCT)']
> + if IfAll(['defined(TEST_IF_UNION_BAR)'])
> + if IfAll(['defined(TEST_IF_UNION) && defined(TEST_IF_STRUCT)'])
> object q_obj_test-if-union-cmd-arg
> member union-cmd-arg: TestIfUnion optional=False
> - if ['defined(TEST_IF_UNION)']
> + if IfAll(['defined(TEST_IF_UNION)'])
> command test-if-union-cmd q_obj_test-if-union-cmd-arg -> None
> gen=True success_response=True boxed=False oob=False preconfig=False
> - if ['defined(TEST_IF_UNION)']
> + if IfAll(['defined(TEST_IF_UNION)'])
> alternate TestIfAlternate
> tag type
> case foo: int
> case bar: TestStruct
> - if ['defined(TEST_IF_ALT_BAR)']
> - if ['defined(TEST_IF_ALT) && defined(TEST_IF_STRUCT)']
> + if IfAll(['defined(TEST_IF_ALT_BAR)'])
> + if IfAll(['defined(TEST_IF_ALT) && defined(TEST_IF_STRUCT)'])
> object q_obj_test-if-alternate-cmd-arg
> member alt-cmd-arg: TestIfAlternate optional=False
> - if ['defined(TEST_IF_ALT)']
> + if IfAll(['defined(TEST_IF_ALT)'])
> command test-if-alternate-cmd q_obj_test-if-alternate-cmd-arg -> None
> gen=True success_response=True boxed=False oob=False preconfig=False
> - if ['defined(TEST_IF_ALT)']
> + if IfAll(['defined(TEST_IF_ALT)'])
> object q_obj_test-if-cmd-arg
> member foo: TestIfStruct optional=False
> member bar: TestIfEnum optional=False
> - if ['defined(TEST_IF_CMD_BAR)']
> - if ['defined(TEST_IF_CMD)', 'defined(TEST_IF_STRUCT)']
> + if IfAll(['defined(TEST_IF_CMD_BAR)'])
> + if IfAll(['defined(TEST_IF_CMD)', 'defined(TEST_IF_STRUCT)'])
> command test-if-cmd q_obj_test-if-cmd-arg -> UserDefThree
> gen=True success_response=True boxed=False oob=False preconfig=False
> - if ['defined(TEST_IF_CMD)', 'defined(TEST_IF_STRUCT)']
> + if IfAll(['defined(TEST_IF_CMD)', 'defined(TEST_IF_STRUCT)'])
> command test-cmd-return-def-three None -> UserDefThree
> gen=True success_response=True boxed=False oob=False preconfig=False
> array TestIfEnumList TestIfEnum
> - if ['defined(TEST_IF_ENUM)']
> + if IfAll(['defined(TEST_IF_ENUM)'])
> object q_obj_TEST_IF_EVENT-arg
> member foo: TestIfStruct optional=False
> member bar: TestIfEnumList optional=False
> - if ['defined(TEST_IF_EVT_BAR)']
> - if ['defined(TEST_IF_EVT) && defined(TEST_IF_STRUCT)']
> + if IfAll(['defined(TEST_IF_EVT_BAR)'])
> + if IfAll(['defined(TEST_IF_EVT) && defined(TEST_IF_STRUCT)'])
> event TEST_IF_EVENT q_obj_TEST_IF_EVENT-arg
> boxed=False
> - if ['defined(TEST_IF_EVT) && defined(TEST_IF_STRUCT)']
> + if IfAll(['defined(TEST_IF_EVT) && defined(TEST_IF_STRUCT)'])
> object FeatureStruct0
> member foo: int optional=False
> object FeatureStruct1
> @@ -379,17 +379,17 @@ object FeatureStruct4
> object CondFeatureStruct1
> member foo: int optional=False
> feature feature1
> - if ['defined(TEST_IF_FEATURE_1)']
> + if IfAll(['defined(TEST_IF_FEATURE_1)'])
> object CondFeatureStruct2
> member foo: int optional=False
> feature feature1
> - if ['defined(TEST_IF_FEATURE_1)']
> + if IfAll(['defined(TEST_IF_FEATURE_1)'])
> feature feature2
> - if ['defined(TEST_IF_FEATURE_2)']
> + if IfAll(['defined(TEST_IF_FEATURE_2)'])
> object CondFeatureStruct3
> member foo: int optional=False
> feature feature1
> - if ['defined(TEST_IF_COND_1)', 'defined(TEST_IF_COND_2)']
> + if IfAll(['defined(TEST_IF_COND_1)', 'defined(TEST_IF_COND_2)'])
> enum FeatureEnum1
> member eins
> member zwei
> @@ -429,17 +429,17 @@ command test-command-features3 None -> None
> command test-command-cond-features1 None -> None
> gen=True success_response=True boxed=False oob=False preconfig=False
> feature feature1
> - if ['defined(TEST_IF_FEATURE_1)']
> + if IfAll(['defined(TEST_IF_FEATURE_1)'])
> command test-command-cond-features2 None -> None
> gen=True success_response=True boxed=False oob=False preconfig=False
> feature feature1
> - if ['defined(TEST_IF_FEATURE_1)']
> + if IfAll(['defined(TEST_IF_FEATURE_1)'])
> feature feature2
> - if ['defined(TEST_IF_FEATURE_2)']
> + if IfAll(['defined(TEST_IF_FEATURE_2)'])
> command test-command-cond-features3 None -> None
> gen=True success_response=True boxed=False oob=False preconfig=False
> feature feature1
> - if ['defined(TEST_IF_COND_1)', 'defined(TEST_IF_COND_2)']
> + if IfAll(['defined(TEST_IF_COND_1)', 'defined(TEST_IF_COND_2)'])
> event TEST_EVENT_FEATURES0 FeatureStruct1
> boxed=False
> event TEST_EVENT_FEATURES1 None
>
Tested-by: John Snow <jsnow@redhat.com>
Seems fine again, minor style qualms about Python I am not that direly
opinionated on. More worried about the integration of cgen and docgen,
though I see why with a predicate tree it becomes *extremely* convenient
to integrate them right into the class.
Is there a way to have our cake and eat it, too ... ?
(Maybe a visitor of some kind is the right way to go?)
That's also what I thought (it was in my commit message comments). Repeating myself, I'd defer this, there is no urge to make the code more complex yet. It can easily be done in a following iteration.