Source code for

"""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

    from typing import Optional, Iterator

def is_from_cache(response):
    # type: (Response) -> bool
    return getattr(response, "from_cache", False)

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.
    except (OSError, IOError):

[docs]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(SafeFileCache, self).__init__() = directory
[docs] 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(, *parts)
[docs] 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
[docs] 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(, path)
[docs] def delete(self, key): # type: (str) -> None path = self._get_cache_path(key) with suppressed_cache_errors(): os.remove(path)