Initial commit

venv/Lib/site-packages/black/cache.py

@@ -0,0 +1,149 @@
+"""Caching of formatted files with feature-based invalidation."""
+
+import hashlib
+import os
+import pickle
+import sys
+import tempfile
+from dataclasses import dataclass, field
+from pathlib import Path
+from typing import Iterable, NamedTuple
+
+from platformdirs import user_cache_dir
+
+from _black_version import version as __version__
+from black.mode import Mode
+from black.output import err
+
+if sys.version_info >= (3, 11):
+    from typing import Self
+else:
+    from typing_extensions import Self
+
+
+class FileData(NamedTuple):
+    st_mtime: float
+    st_size: int
+    hash: str
+
+
+def get_cache_dir() -> Path:
+    """Get the cache directory used by black.
+
+    Users can customize this directory on all systems using `BLACK_CACHE_DIR`
+    environment variable. By default, the cache directory is the user cache directory
+    under the black application.
+
+    This result is immediately set to a constant `black.cache.CACHE_DIR` as to avoid
+    repeated calls.
+    """
+    # NOTE: Function mostly exists as a clean way to test getting the cache directory.
+    default_cache_dir = user_cache_dir("black")
+    cache_dir = Path(os.environ.get("BLACK_CACHE_DIR", default_cache_dir))
+    cache_dir = cache_dir / __version__
+    return cache_dir
+
+
+CACHE_DIR = get_cache_dir()
+
+
+def get_cache_file(mode: Mode) -> Path:
+    return CACHE_DIR / f"cache.{mode.get_cache_key()}.pickle"
+
+
+@dataclass
+class Cache:
+    mode: Mode
+    cache_file: Path
+    file_data: dict[str, FileData] = field(default_factory=dict)
+
+    @classmethod
+    def read(cls, mode: Mode) -> Self:
+        """Read the cache if it exists and is well-formed.
+
+        If it is not well-formed, the call to write later should
+        resolve the issue.
+        """
+        cache_file = get_cache_file(mode)
+        try:
+            exists = cache_file.exists()
+        except OSError as e:
+            # Likely file too long; see #4172 and #4174
+            err(f"Unable to read cache file {cache_file} due to {e}")
+            return cls(mode, cache_file)
+        if not exists:
+            return cls(mode, cache_file)
+
+        with cache_file.open("rb") as fobj:
+            try:
+                data: dict[str, tuple[float, int, str]] = pickle.load(fobj)
+                file_data = {k: FileData(*v) for k, v in data.items()}
+            except (pickle.UnpicklingError, ValueError, IndexError):
+                return cls(mode, cache_file)
+
+        return cls(mode, cache_file, file_data)
+
+    @staticmethod
+    def hash_digest(path: Path) -> str:
+        """Return hash digest for path."""
+
+        data = path.read_bytes()
+        return hashlib.sha256(data).hexdigest()
+
+    @staticmethod
+    def get_file_data(path: Path) -> FileData:
+        """Return file data for path."""
+
+        stat = path.stat()
+        hash = Cache.hash_digest(path)
+        return FileData(stat.st_mtime, stat.st_size, hash)
+
+    def is_changed(self, source: Path) -> bool:
+        """Check if source has changed compared to cached version."""
+        res_src = source.resolve()
+        old = self.file_data.get(str(res_src))
+        if old is None:
+            return True
+
+        st = res_src.stat()
+        if st.st_size != old.st_size:
+            return True
+        if st.st_mtime != old.st_mtime:
+            new_hash = Cache.hash_digest(res_src)
+            if new_hash != old.hash:
+                return True
+        return False
+
+    def filtered_cached(self, sources: Iterable[Path]) -> tuple[set[Path], set[Path]]:
+        """Split an iterable of paths in `sources` into two sets.
+
+        The first contains paths of files that modified on disk or are not in the
+        cache. The other contains paths to non-modified files.
+        """
+        changed: set[Path] = set()
+        done: set[Path] = set()
+        for src in sources:
+            if self.is_changed(src):
+                changed.add(src)
+            else:
+                done.add(src)
+        return changed, done
+
+    def write(self, sources: Iterable[Path]) -> None:
+        """Update the cache file data and write a new cache file."""
+        self.file_data.update(
+            **{str(src.resolve()): Cache.get_file_data(src) for src in sources}
+        )
+        try:
+            CACHE_DIR.mkdir(parents=True, exist_ok=True)
+            with tempfile.NamedTemporaryFile(
+                dir=str(self.cache_file.parent), delete=False
+            ) as f:
+                # We store raw tuples in the cache because it's faster.
+                data: dict[str, tuple[float, int, str]] = {
+                    k: (*v,) for k, v in self.file_data.items()
+                }
+                pickle.dump(data, f, protocol=4)
+            os.replace(f.name, self.cache_file)
+        except OSError:
+            pass