djavu-asus/elpy/rpc-venv/lib/python3.11/site-packages/black/cache.py

   1 """Caching of formatted files with feature-based invalidation."""
   2 import hashlib
   3 import os
   4 import pickle
   5 import sys
   6 import tempfile
   7 from dataclasses import dataclass, field
   8 from pathlib import Path
   9 from typing import Dict, Iterable, NamedTuple, Set, Tuple
  10
  11 from platformdirs import user_cache_dir
  12
  13 from _black_version import version as __version__
  14 from black.mode import Mode
  15
  16 if sys.version_info >= (3, 11):
  17     from typing import Self
  18 else:
  19     from typing_extensions import Self
  20
  21
  22 class FileData(NamedTuple):
  23     st_mtime: float
  24     st_size: int
  25     hash: str
  26
  27
  28 def get_cache_dir() -> Path:
  29     """Get the cache directory used by black.
  30
  31     Users can customize this directory on all systems using `BLACK_CACHE_DIR`
  32     environment variable. By default, the cache directory is the user cache directory
  33     under the black application.
  34
  35     This result is immediately set to a constant `black.cache.CACHE_DIR` as to avoid
  36     repeated calls.
  37     """
  38     # NOTE: Function mostly exists as a clean way to test getting the cache directory.
  39     default_cache_dir = user_cache_dir("black", version=__version__)
  40     cache_dir = Path(os.environ.get("BLACK_CACHE_DIR", default_cache_dir))
  41     return cache_dir
  42
  43
  44 CACHE_DIR = get_cache_dir()
  45
  46
  47 def get_cache_file(mode: Mode) -> Path:
  48     return CACHE_DIR / f"cache.{mode.get_cache_key()}.pickle"
  49
  50
  51 @dataclass
  52 class Cache:
  53     mode: Mode
  54     cache_file: Path
  55     file_data: Dict[str, FileData] = field(default_factory=dict)
  56
  57     @classmethod
  58     def read(cls, mode: Mode) -> Self:
  59         """Read the cache if it exists and is well formed.
  60
  61         If it is not well formed, the call to write later should
  62         resolve the issue.
  63         """
  64         cache_file = get_cache_file(mode)
  65         if not cache_file.exists():
  66             return cls(mode, cache_file)
  67
  68         with cache_file.open("rb") as fobj:
  69             try:
  70                 data: Dict[str, Tuple[float, int, str]] = pickle.load(fobj)
  71                 file_data = {k: FileData(*v) for k, v in data.items()}
  72             except (pickle.UnpicklingError, ValueError, IndexError):
  73                 return cls(mode, cache_file)
  74
  75         return cls(mode, cache_file, file_data)
  76
  77     @staticmethod
  78     def hash_digest(path: Path) -> str:
  79         """Return hash digest for path."""
  80
  81         data = path.read_bytes()
  82         return hashlib.sha256(data).hexdigest()
  83
  84     @staticmethod
  85     def get_file_data(path: Path) -> FileData:
  86         """Return file data for path."""
  87
  88         stat = path.stat()
  89         hash = Cache.hash_digest(path)
  90         return FileData(stat.st_mtime, stat.st_size, hash)
  91
  92     def is_changed(self, source: Path) -> bool:
  93         """Check if source has changed compared to cached version."""
  94         res_src = source.resolve()
  95         old = self.file_data.get(str(res_src))
  96         if old is None:
  97             return True
  98
  99         st = res_src.stat()
 100         if st.st_size != old.st_size:
 101             return True
 102         if int(st.st_mtime) != int(old.st_mtime):
 103             new_hash = Cache.hash_digest(res_src)
 104             if new_hash != old.hash:
 105                 return True
 106         return False
 107
 108     def filtered_cached(self, sources: Iterable[Path]) -> Tuple[Set[Path], Set[Path]]:
 109         """Split an iterable of paths in `sources` into two sets.
 110
 111         The first contains paths of files that modified on disk or are not in the
 112         cache. The other contains paths to non-modified files.
 113         """
 114         changed: Set[Path] = set()
 115         done: Set[Path] = set()
 116         for src in sources:
 117             if self.is_changed(src):
 118                 changed.add(src)
 119             else:
 120                 done.add(src)
 121         return changed, done
 122
 123     def write(self, sources: Iterable[Path]) -> None:
 124         """Update the cache file data and write a new cache file."""
 125         self.file_data.update(
 126             **{str(src.resolve()): Cache.get_file_data(src) for src in sources}
 127         )
 128         try:
 129             CACHE_DIR.mkdir(parents=True, exist_ok=True)
 130             with tempfile.NamedTemporaryFile(
 131                 dir=str(self.cache_file.parent), delete=False
 132             ) as f:
 133                 # We store raw tuples in the cache because pickling NamedTuples
 134                 # doesn't work with mypyc on Python 3.8, and because it's faster.
 135                 data: Dict[str, Tuple[float, int, str]] = {
 136                     k: (*v,) for k, v in self.file_data.items()
 137                 }
 138                 pickle.dump(data, f, protocol=4)
 139             os.replace(f.name, self.cache_file)
 140         except OSError:
 141             pass