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# SPDX-License-Identifier: Apache-2.0
# Copyright © 2022-2023 Intel Corporation
"""Rust CFG parser.
Rust uses its `cfg()` format in cargo.
https://doc.rust-lang.org/reference/conditional-compilation.html
This may have the following functions:
- all()
- any()
- not()
And additionally is made up of `identifier [ = str]`. Where the str is optional,
so you could have examples like:
```
[target.`cfg(unix)`.dependencies]
[target.'cfg(target_arch = "x86_64")'.dependencies]
[target.'cfg(all(target_arch = "x86_64", target_arch = "x86"))'.dependencies]
```
"""
from __future__ import annotations
import dataclasses
import enum
import typing as T
from ..mesonlib import MesonBugException
if T.TYPE_CHECKING:
_T = T.TypeVar('_T')
_LEX_TOKEN = T.Tuple['TokenType', T.Optional[str]]
_LEX_STREAM = T.Iterator[_LEX_TOKEN]
_LEX_STREAM_AH = T.Iterator[T.Tuple[_LEX_TOKEN, T.Optional[_LEX_TOKEN]]]
class TokenType(enum.Enum):
LPAREN = enum.auto()
RPAREN = enum.auto()
STRING = enum.auto()
IDENTIFIER = enum.auto()
ALL = enum.auto()
ANY = enum.auto()
NOT = enum.auto()
COMMA = enum.auto()
EQUAL = enum.auto()
CFG = enum.auto()
def lexer(raw: str) -> _LEX_STREAM:
"""Lex a cfg() expression.
:param raw: The raw cfg() expression
:return: An iterable of tokens
"""
start: int = 0
is_string: bool = False
for i, s in enumerate(raw):
if s.isspace() or s in {')', '(', ',', '=', '"'}:
val = raw[start:i]
start = i + 1
if s == '"' and is_string:
yield (TokenType.STRING, val)
is_string = False
continue
elif val == 'any':
yield (TokenType.ANY, None)
elif val == 'all':
yield (TokenType.ALL, None)
elif val == 'not':
yield (TokenType.NOT, None)
elif val == 'cfg':
yield (TokenType.CFG, None)
elif val:
yield (TokenType.IDENTIFIER, val)
if s == '(':
yield (TokenType.LPAREN, None)
elif s == ')':
yield (TokenType.RPAREN, None)
elif s == ',':
yield (TokenType.COMMA, None)
elif s == '=':
yield (TokenType.EQUAL, None)
elif s == '"':
is_string = True
val = raw[start:]
if val:
# This should always be an identifier
yield (TokenType.IDENTIFIER, val)
def lookahead(iter: T.Iterator[_T]) -> T.Iterator[T.Tuple[_T, T.Optional[_T]]]:
"""Get the current value of the iterable, and the next if possible.
:param iter: The iterable to look into
:yield: A tuple of the current value, and, if possible, the next
:return: nothing
"""
current: _T
next_: T.Optional[_T]
try:
next_ = next(iter)
except StopIteration:
# This is an empty iterator, there's nothing to look ahead to
return
while True:
current = next_
try:
next_ = next(iter)
except StopIteration:
next_ = None
yield current, next_
if next_ is None:
break
@dataclasses.dataclass
class IR:
"""Base IR node for Cargo CFG."""
@dataclasses.dataclass
class String(IR):
value: str
@dataclasses.dataclass
class Identifier(IR):
value: str
@dataclasses.dataclass
class Equal(IR):
lhs: Identifier
rhs: String
@dataclasses.dataclass
class Any(IR):
args: T.List[IR]
@dataclasses.dataclass
class All(IR):
args: T.List[IR]
@dataclasses.dataclass
class Not(IR):
value: IR
def _parse(ast: _LEX_STREAM_AH) -> IR:
(token, value), n_stream = next(ast)
if n_stream is not None:
ntoken, _ = n_stream
else:
ntoken, _ = (None, None)
if token is TokenType.IDENTIFIER:
assert value
id_ = Identifier(value)
if ntoken is TokenType.EQUAL:
next(ast)
(token, value), _ = next(ast)
assert token is TokenType.STRING
assert value is not None
return Equal(id_, String(value))
return id_
elif token in {TokenType.ANY, TokenType.ALL}:
type_ = All if token is TokenType.ALL else Any
args: T.List[IR] = []
(token, value), n_stream = next(ast)
assert token is TokenType.LPAREN
if n_stream and n_stream[0] == TokenType.RPAREN:
return type_(args)
while True:
args.append(_parse(ast))
(token, value), _ = next(ast)
if token is TokenType.RPAREN:
break
assert token is TokenType.COMMA
return type_(args)
elif token in {TokenType.NOT, TokenType.CFG}:
is_not = token is TokenType.NOT
(token, value), _ = next(ast)
assert token is TokenType.LPAREN
arg = _parse(ast)
(token, value), _ = next(ast)
assert token is TokenType.RPAREN
return Not(arg) if is_not else arg
else:
raise MesonBugException(f'Unhandled Cargo token:{token} {value}')
def parse(ast: _LEX_STREAM) -> IR:
"""Parse the tokenized list into Meson AST.
:param ast: An iterable of Tokens
:return: An mparser Node to be used as a conditional
"""
ast_i: _LEX_STREAM_AH = lookahead(ast)
return _parse(ast_i)
def _eval_cfg(ir: IR, cfgs: T.Dict[str, str]) -> bool:
if isinstance(ir, Identifier):
return ir.value in cfgs
elif isinstance(ir, Equal):
return cfgs.get(ir.lhs.value) == ir.rhs.value
elif isinstance(ir, Not):
return not _eval_cfg(ir.value, cfgs)
elif isinstance(ir, Any):
return any(_eval_cfg(i, cfgs) for i in ir.args)
elif isinstance(ir, All):
return all(_eval_cfg(i, cfgs) for i in ir.args)
else:
raise MesonBugException(f'Unhandled Cargo cfg IR: {ir}')
def eval_cfg(raw: str, cfgs: T.Dict[str, str]) -> bool:
return _eval_cfg(parse(lexer(raw)), cfgs)
|
