diff env/lib/python3.9/site-packages/pip/_internal/network/cache.py @ 0:4f3585e2f14b draft default tip

"planemo upload commit 60cee0fc7c0cda8592644e1aad72851dec82c959"

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/env/lib/python3.9/site-packages/pip/_internal/network/cache.py	Mon Mar 22 18:12:50 2021 +0000
@@ -0,0 +1,79 @@
+"""HTTP cache implementation.
+"""
+
+import os
+from contextlib import contextmanager
+
+from pip._vendor.cachecontrol.cache import BaseCache
+from pip._vendor.cachecontrol.caches import FileCache
+from pip._vendor.requests.models import Response
+
+from pip._internal.utils.filesystem import adjacent_tmp_file, replace
+from pip._internal.utils.misc import ensure_dir
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from typing import Iterator, Optional
+
+
+def is_from_cache(response):
+    # type: (Response) -> bool
+    return getattr(response, "from_cache", False)
+
+
+@contextmanager
+def suppressed_cache_errors():
+    # type: () -> Iterator[None]
+    """If we can't access the cache then we can just skip caching and process
+    requests as if caching wasn't enabled.
+    """
+    try:
+        yield
+    except OSError:
+        pass
+
+
+class SafeFileCache(BaseCache):
+    """
+    A file based cache which is safe to use even when the target directory may
+    not be accessible or writable.
+    """
+
+    def __init__(self, directory):
+        # type: (str) -> None
+        assert directory is not None, "Cache directory must not be None."
+        super().__init__()
+        self.directory = directory
+
+    def _get_cache_path(self, name):
+        # type: (str) -> str
+        # From cachecontrol.caches.file_cache.FileCache._fn, brought into our
+        # class for backwards-compatibility and to avoid using a non-public
+        # method.
+        hashed = FileCache.encode(name)
+        parts = list(hashed[:5]) + [hashed]
+        return os.path.join(self.directory, *parts)
+
+    def get(self, key):
+        # type: (str) -> Optional[bytes]
+        path = self._get_cache_path(key)
+        with suppressed_cache_errors():
+            with open(path, 'rb') as f:
+                return f.read()
+
+    def set(self, key, value):
+        # type: (str, bytes) -> None
+        path = self._get_cache_path(key)
+        with suppressed_cache_errors():
+            ensure_dir(os.path.dirname(path))
+
+            with adjacent_tmp_file(path) as f:
+                f.write(value)
+
+            replace(f.name, path)
+
+    def delete(self, key):
+        # type: (str) -> None
+        path = self._get_cache_path(key)
+        with suppressed_cache_errors():
+            os.remove(path)