]> git.madduck.net Git - etc/vim.git/blobdiff - src/black/cache.py

madduck's git repository

Every one of the projects in this repository is available at the canonical URL git://git.madduck.net/madduck/pub/<projectpath> — see each project's metadata for the exact URL.

All patches and comments are welcome. Please squash your changes to logical commits before using git-format-patch and git-send-email to patches@git.madduck.net. If you'd read over the Git project's submission guidelines and adhered to them, I'd be especially grateful.

SSH access, as well as push access can be individually arranged.

If you use my repositories frequently, consider adding the following snippet to ~/.gitconfig and using the third clone URL listed for each project:

[url "git://git.madduck.net/madduck/"]
  insteadOf = madduck:

Improve caching by comparing file hashes as fallback for mtime and size (#3821)
[etc/vim.git] / src / black / cache.py
index 9455ff4477250b78e279040124dcc7215e2e351b..ff15da2a94ea89c81867146856fc6dfa23843b8b 100644 (file)
@@ -1,21 +1,28 @@
 """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 Dict, Iterable, Set, Tuple
+from typing import Dict, Iterable, NamedTuple, Set, Tuple
 
 from platformdirs import user_cache_dir
 
 from _black_version import version as __version__
 from black.mode import Mode
 
-# types
-Timestamp = float
-FileSize = int
-CacheInfo = Tuple[Timestamp, FileSize]
-Cache = Dict[str, CacheInfo]
+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:
@@ -37,61 +44,92 @@ def get_cache_dir() -> Path:
 CACHE_DIR = get_cache_dir()
 
 
-def read_cache(mode: Mode) -> Cache:
-    """Read the cache if it exists and is well formed.
-
-    If it is not well formed, the call to write_cache later should resolve the issue.
-    """
-    cache_file = get_cache_file(mode)
-    if not cache_file.exists():
-        return {}
-
-    with cache_file.open("rb") as fobj:
-        try:
-            cache: Cache = pickle.load(fobj)
-        except (pickle.UnpicklingError, ValueError, IndexError):
-            return {}
-
-    return cache
-
-
 def get_cache_file(mode: Mode) -> Path:
     return CACHE_DIR / f"cache.{mode.get_cache_key()}.pickle"
 
 
-def get_cache_info(path: Path) -> CacheInfo:
-    """Return the information used to check if a file is already formatted or not."""
-    stat = path.stat()
-    return stat.st_mtime, stat.st_size
-
-
-def filter_cached(cache: Cache, 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.
-    """
-    todo, done = set(), set()
-    for src in sources:
-        res_src = src.resolve()
-        if cache.get(str(res_src)) != get_cache_info(res_src):
-            todo.add(src)
-        else:
-            done.add(src)
-    return todo, done
-
-
-def write_cache(cache: Cache, sources: Iterable[Path], mode: Mode) -> None:
-    """Update the cache file."""
-    cache_file = get_cache_file(mode)
-    try:
-        CACHE_DIR.mkdir(parents=True, exist_ok=True)
-        new_cache = {
-            **cache,
-            **{str(src.resolve()): get_cache_info(src) for src in sources},
-        }
-        with tempfile.NamedTemporaryFile(dir=str(cache_file.parent), delete=False) as f:
-            pickle.dump(new_cache, f, protocol=4)
-        os.replace(f.name, cache_file)
-    except OSError:
-        pass
+@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)
+        if not cache_file.exists():
+            return cls(mode, cache_file)
+
+        with cache_file.open("rb") as fobj:
+            try:
+                file_data: Dict[str, FileData] = pickle.load(fobj)
+            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 int(st.st_mtime) != int(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:
+                pickle.dump(self.file_data, f, protocol=4)
+            os.replace(f.name, self.cache_file)
+        except OSError:
+            pass