about summary refs log tree commit diff
path: root/.venv/lib/python3.12/site-packages/pip/_vendor/cachecontrol/filewrapper.py
diff options
context:
space:
mode:
Diffstat (limited to '.venv/lib/python3.12/site-packages/pip/_vendor/cachecontrol/filewrapper.py')
-rw-r--r--.venv/lib/python3.12/site-packages/pip/_vendor/cachecontrol/filewrapper.py119
1 files changed, 119 insertions, 0 deletions
diff --git a/.venv/lib/python3.12/site-packages/pip/_vendor/cachecontrol/filewrapper.py b/.venv/lib/python3.12/site-packages/pip/_vendor/cachecontrol/filewrapper.py
new file mode 100644
index 00000000..37d2fa59
--- /dev/null
+++ b/.venv/lib/python3.12/site-packages/pip/_vendor/cachecontrol/filewrapper.py
@@ -0,0 +1,119 @@
+# SPDX-FileCopyrightText: 2015 Eric Larson
+#
+# SPDX-License-Identifier: Apache-2.0
+from __future__ import annotations
+
+import mmap
+from tempfile import NamedTemporaryFile
+from typing import TYPE_CHECKING, Any, Callable
+
+if TYPE_CHECKING:
+    from http.client import HTTPResponse
+
+
+class CallbackFileWrapper:
+    """
+    Small wrapper around a fp object which will tee everything read into a
+    buffer, and when that file is closed it will execute a callback with the
+    contents of that buffer.
+
+    All attributes are proxied to the underlying file object.
+
+    This class uses members with a double underscore (__) leading prefix so as
+    not to accidentally shadow an attribute.
+
+    The data is stored in a temporary file until it is all available.  As long
+    as the temporary files directory is disk-based (sometimes it's a
+    memory-backed-``tmpfs`` on Linux), data will be unloaded to disk if memory
+    pressure is high.  For small files the disk usually won't be used at all,
+    it'll all be in the filesystem memory cache, so there should be no
+    performance impact.
+    """
+
+    def __init__(
+        self, fp: HTTPResponse, callback: Callable[[bytes], None] | None
+    ) -> None:
+        self.__buf = NamedTemporaryFile("rb+", delete=True)
+        self.__fp = fp
+        self.__callback = callback
+
+    def __getattr__(self, name: str) -> Any:
+        # The vagaries of garbage collection means that self.__fp is
+        # not always set.  By using __getattribute__ and the private
+        # name[0] allows looking up the attribute value and raising an
+        # AttributeError when it doesn't exist. This stop things from
+        # infinitely recursing calls to getattr in the case where
+        # self.__fp hasn't been set.
+        #
+        # [0] https://docs.python.org/2/reference/expressions.html#atom-identifiers
+        fp = self.__getattribute__("_CallbackFileWrapper__fp")
+        return getattr(fp, name)
+
+    def __is_fp_closed(self) -> bool:
+        try:
+            return self.__fp.fp is None
+
+        except AttributeError:
+            pass
+
+        try:
+            closed: bool = self.__fp.closed
+            return closed
+
+        except AttributeError:
+            pass
+
+        # We just don't cache it then.
+        # TODO: Add some logging here...
+        return False
+
+    def _close(self) -> None:
+        if self.__callback:
+            if self.__buf.tell() == 0:
+                # Empty file:
+                result = b""
+            else:
+                # Return the data without actually loading it into memory,
+                # relying on Python's buffer API and mmap(). mmap() just gives
+                # a view directly into the filesystem's memory cache, so it
+                # doesn't result in duplicate memory use.
+                self.__buf.seek(0, 0)
+                result = memoryview(
+                    mmap.mmap(self.__buf.fileno(), 0, access=mmap.ACCESS_READ)
+                )
+            self.__callback(result)
+
+        # We assign this to None here, because otherwise we can get into
+        # really tricky problems where the CPython interpreter dead locks
+        # because the callback is holding a reference to something which
+        # has a __del__ method. Setting this to None breaks the cycle
+        # and allows the garbage collector to do it's thing normally.
+        self.__callback = None
+
+        # Closing the temporary file releases memory and frees disk space.
+        # Important when caching big files.
+        self.__buf.close()
+
+    def read(self, amt: int | None = None) -> bytes:
+        data: bytes = self.__fp.read(amt)
+        if data:
+            # We may be dealing with b'', a sign that things are over:
+            # it's passed e.g. after we've already closed self.__buf.
+            self.__buf.write(data)
+        if self.__is_fp_closed():
+            self._close()
+
+        return data
+
+    def _safe_read(self, amt: int) -> bytes:
+        data: bytes = self.__fp._safe_read(amt)  # type: ignore[attr-defined]
+        if amt == 2 and data == b"\r\n":
+            # urllib executes this read to toss the CRLF at the end
+            # of the chunk.
+            return data
+
+        self.__buf.write(data)
+        if self.__is_fp_closed():
+            self._close()
+
+        return data