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from __future__ import annotations
from copy import copy
from typing import Any
from tomlkit.exceptions import ParseError
from tomlkit.exceptions import UnexpectedCharError
from tomlkit.toml_char import TOMLChar
class _State:
def __init__(
self,
source: Source,
save_marker: bool | None = False,
restore: bool | None = False,
) -> None:
self._source = source
self._save_marker = save_marker
self.restore = restore
def __enter__(self) -> _State:
# Entering this context manager - save the state
self._chars = copy(self._source._chars)
self._idx = self._source._idx
self._current = self._source._current
self._marker = self._source._marker
return self
def __exit__(self, exception_type, exception_val, trace):
# Exiting this context manager - restore the prior state
if self.restore or exception_type:
self._source._chars = self._chars
self._source._idx = self._idx
self._source._current = self._current
if self._save_marker:
self._source._marker = self._marker
class _StateHandler:
"""
State preserver for the Parser.
"""
def __init__(self, source: Source) -> None:
self._source = source
self._states = []
def __call__(self, *args, **kwargs):
return _State(self._source, *args, **kwargs)
def __enter__(self) -> None:
state = self()
self._states.append(state)
return state.__enter__()
def __exit__(self, exception_type, exception_val, trace):
state = self._states.pop()
return state.__exit__(exception_type, exception_val, trace)
class Source(str):
EOF = TOMLChar("\0")
def __init__(self, _: str) -> None:
super().__init__()
# Collection of TOMLChars
self._chars = iter([(i, TOMLChar(c)) for i, c in enumerate(self)])
self._idx = 0
self._marker = 0
self._current = TOMLChar("")
self._state = _StateHandler(self)
self.inc()
def reset(self):
# initialize both idx and current
self.inc()
# reset marker
self.mark()
@property
def state(self) -> _StateHandler:
return self._state
@property
def idx(self) -> int:
return self._idx
@property
def current(self) -> TOMLChar:
return self._current
@property
def marker(self) -> int:
return self._marker
def extract(self) -> str:
"""
Extracts the value between marker and index
"""
return self[self._marker : self._idx]
def inc(self, exception: type[ParseError] | None = None) -> bool:
"""
Increments the parser if the end of the input has not been reached.
Returns whether or not it was able to advance.
"""
try:
self._idx, self._current = next(self._chars)
return True
except StopIteration:
self._idx = len(self)
self._current = self.EOF
if exception:
raise self.parse_error(exception)
return False
def inc_n(self, n: int, exception: type[ParseError] | None = None) -> bool:
"""
Increments the parser by n characters
if the end of the input has not been reached.
"""
return all(self.inc(exception=exception) for _ in range(n))
def consume(self, chars, min=0, max=-1):
"""
Consume chars until min/max is satisfied is valid.
"""
while self.current in chars and max != 0:
min -= 1
max -= 1
if not self.inc():
break
# failed to consume minimum number of characters
if min > 0:
raise self.parse_error(UnexpectedCharError, self.current)
def end(self) -> bool:
"""
Returns True if the parser has reached the end of the input.
"""
return self._current is self.EOF
def mark(self) -> None:
"""
Sets the marker to the index's current position
"""
self._marker = self._idx
def parse_error(
self,
exception: type[ParseError] = ParseError,
*args: Any,
**kwargs: Any,
) -> ParseError:
"""
Creates a generic "parse error" at the current position.
"""
line, col = self._to_linecol()
return exception(line, col, *args, **kwargs)
def _to_linecol(self) -> tuple[int, int]:
cur = 0
for i, line in enumerate(self.splitlines()):
if cur + len(line) + 1 > self.idx:
return (i + 1, self.idx - cur)
cur += len(line) + 1
return len(self.splitlines()), 0
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