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-rw-r--r--mesonbuild/interpreterbase/baseobjects.py182
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diff --git a/mesonbuild/interpreterbase/baseobjects.py b/mesonbuild/interpreterbase/baseobjects.py
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+# Copyright 2013-2021 The Meson development team
+
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+
+# http://www.apache.org/licenses/LICENSE-2.0
+
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+from __future__ import annotations
+
+from .. import mparser
+from .exceptions import InvalidCode, InvalidArguments
+from .helpers import flatten, resolve_second_level_holders
+from .operator import MesonOperator
+from ..mesonlib import HoldableObject, MesonBugException
+import textwrap
+
+import typing as T
+from abc import ABCMeta
+
+if T.TYPE_CHECKING:
+ from typing_extensions import Protocol
+
+ # Object holders need the actual interpreter
+ from ..interpreter import Interpreter
+
+ __T = T.TypeVar('__T', bound='TYPE_var', contravariant=True)
+
+ class OperatorCall(Protocol[__T]):
+ def __call__(self, other: __T) -> 'TYPE_var': ...
+
+TV_fw_var = T.Union[str, int, bool, list, dict, 'InterpreterObject']
+TV_fw_args = T.List[T.Union[mparser.BaseNode, TV_fw_var]]
+TV_fw_kwargs = T.Dict[str, T.Union[mparser.BaseNode, TV_fw_var]]
+
+TV_func = T.TypeVar('TV_func', bound=T.Callable[..., T.Any])
+
+TYPE_elementary = T.Union[str, int, bool, T.List[T.Any], T.Dict[str, T.Any]]
+TYPE_var = T.Union[TYPE_elementary, HoldableObject, 'MesonInterpreterObject']
+TYPE_nvar = T.Union[TYPE_var, mparser.BaseNode]
+TYPE_kwargs = T.Dict[str, TYPE_var]
+TYPE_nkwargs = T.Dict[str, TYPE_nvar]
+TYPE_key_resolver = T.Callable[[mparser.BaseNode], str]
+
+SubProject = T.NewType('SubProject', str)
+
+class InterpreterObject:
+ def __init__(self, *, subproject: T.Optional['SubProject'] = None) -> None:
+ self.methods: T.Dict[
+ str,
+ T.Callable[[T.List[TYPE_var], TYPE_kwargs], TYPE_var]
+ ] = {}
+ self.operators: T.Dict[MesonOperator, 'OperatorCall'] = {}
+ self.trivial_operators: T.Dict[
+ MesonOperator,
+ T.Tuple[
+ T.Union[T.Type, T.Tuple[T.Type, ...]],
+ 'OperatorCall'
+ ]
+ ] = {}
+ # Current node set during a method call. This can be used as location
+ # when printing a warning message during a method call.
+ self.current_node: mparser.BaseNode = None
+ self.subproject = subproject or SubProject('')
+
+ # Some default operators supported by all objects
+ self.operators.update({
+ MesonOperator.EQUALS: self.op_equals,
+ MesonOperator.NOT_EQUALS: self.op_not_equals,
+ })
+
+ # The type of the object that can be printed to the user
+ def display_name(self) -> str:
+ return type(self).__name__
+
+ def method_call(
+ self,
+ method_name: str,
+ args: T.List[TYPE_var],
+ kwargs: TYPE_kwargs
+ ) -> TYPE_var:
+ if method_name in self.methods:
+ method = self.methods[method_name]
+ if not getattr(method, 'no-args-flattening', False):
+ args = flatten(args)
+ if not getattr(method, 'no-second-level-holder-flattening', False):
+ args, kwargs = resolve_second_level_holders(args, kwargs)
+ return method(args, kwargs)
+ raise InvalidCode(f'Unknown method "{method_name}" in object {self} of type {type(self).__name__}.')
+
+ def operator_call(self, operator: MesonOperator, other: TYPE_var) -> TYPE_var:
+ if operator in self.trivial_operators:
+ op = self.trivial_operators[operator]
+ if op[0] is None and other is not None:
+ raise MesonBugException(f'The unary operator `{operator.value}` of {self.display_name()} was passed the object {other} of type {type(other).__name__}')
+ if op[0] is not None and not isinstance(other, op[0]):
+ raise InvalidArguments(f'The `{operator.value}` operator of {self.display_name()} does not accept objects of type {type(other).__name__} ({other})')
+ return op[1](other)
+ if operator in self.operators:
+ return self.operators[operator](other)
+ raise InvalidCode(f'Object {self} of type {self.display_name()} does not support the `{operator.value}` operator.')
+
+ # Default comparison operator support
+ def _throw_comp_exception(self, other: TYPE_var, opt_type: str) -> T.NoReturn:
+ raise InvalidArguments(textwrap.dedent(
+ f'''
+ Trying to compare values of different types ({self.display_name()}, {type(other).__name__}) using {opt_type}.
+ This was deprecated and undefined behavior previously and is as of 0.60.0 a hard error.
+ '''
+ ))
+
+ def op_equals(self, other: TYPE_var) -> bool:
+ # We use `type(...) == type(...)` here to enforce an *exact* match for comparison. We
+ # don't want comparisons to be possible where `isinstance(derived_obj, type(base_obj))`
+ # would pass because this comparison must never be true: `derived_obj == base_obj`
+ if type(self) != type(other):
+ self._throw_comp_exception(other, '==')
+ return self == other
+
+ def op_not_equals(self, other: TYPE_var) -> bool:
+ if type(self) != type(other):
+ self._throw_comp_exception(other, '!=')
+ return self != other
+
+class MesonInterpreterObject(InterpreterObject):
+ ''' All non-elementary objects and non-object-holders should be derived from this '''
+
+class MutableInterpreterObject:
+ ''' Dummy class to mark the object type as mutable '''
+
+HoldableTypes = (HoldableObject, int, bool, str, list, dict)
+TYPE_HoldableTypes = T.Union[TYPE_elementary, HoldableObject]
+InterpreterObjectTypeVar = T.TypeVar('InterpreterObjectTypeVar', bound=TYPE_HoldableTypes)
+
+class ObjectHolder(InterpreterObject, T.Generic[InterpreterObjectTypeVar]):
+ def __init__(self, obj: InterpreterObjectTypeVar, interpreter: 'Interpreter') -> None:
+ super().__init__(subproject=interpreter.subproject)
+ # This causes some type checkers to assume that obj is a base
+ # HoldableObject, not the specialized type, so only do this assert in
+ # non-type checking situations
+ if not T.TYPE_CHECKING:
+ assert isinstance(obj, HoldableTypes), f'This is a bug: Trying to hold object of type `{type(obj).__name__}` that is not in `{HoldableTypes}`'
+ self.held_object = obj
+ self.interpreter = interpreter
+ self.env = self.interpreter.environment
+
+ # Hide the object holder abstraction from the user
+ def display_name(self) -> str:
+ return type(self.held_object).__name__
+
+ # Override default comparison operators for the held object
+ def op_equals(self, other: TYPE_var) -> bool:
+ # See the comment from InterpreterObject why we are using `type()` here.
+ if type(self.held_object) != type(other):
+ self._throw_comp_exception(other, '==')
+ return self.held_object == other
+
+ def op_not_equals(self, other: TYPE_var) -> bool:
+ if type(self.held_object) != type(other):
+ self._throw_comp_exception(other, '!=')
+ return self.held_object != other
+
+ def __repr__(self) -> str:
+ return f'<[{type(self).__name__}] holds [{type(self.held_object).__name__}]: {self.held_object!r}>'
+
+class IterableObject(metaclass=ABCMeta):
+ '''Base class for all objects that can be iterated over in a foreach loop'''
+
+ def iter_tuple_size(self) -> T.Optional[int]:
+ '''Return the size of the tuple for each iteration. Returns None if only a single value is returned.'''
+ raise MesonBugException(f'iter_tuple_size not implemented for {self.__class__.__name__}')
+
+ def iter_self(self) -> T.Iterator[T.Union[TYPE_var, T.Tuple[TYPE_var, ...]]]:
+ raise MesonBugException(f'iter not implemented for {self.__class__.__name__}')
+
+ def size(self) -> int:
+ raise MesonBugException(f'size not implemented for {self.__class__.__name__}')