second commit

env/lib/python3.11/site-packages/websockets/datastructures.py

@@ -0,0 +1,183 @@
+from __future__ import annotations
+
+from collections.abc import Iterable, Iterator, Mapping, MutableMapping
+from typing import Any, Protocol, Union
+
+
+__all__ = ["Headers", "HeadersLike", "MultipleValuesError"]
+
+
+class MultipleValuesError(LookupError):
+    """
+    Exception raised when :class:`Headers` has multiple values for a key.
+
+    """
+
+    def __str__(self) -> str:
+        # Implement the same logic as KeyError_str in Objects/exceptions.c.
+        if len(self.args) == 1:
+            return repr(self.args[0])
+        return super().__str__()
+
+
+class Headers(MutableMapping[str, str]):
+    """
+    Efficient data structure for manipulating HTTP headers.
+
+    A :class:`list` of ``(name, values)`` is inefficient for lookups.
+
+    A :class:`dict` doesn't suffice because header names are case-insensitive
+    and multiple occurrences of headers with the same name are possible.
+
+    :class:`Headers` stores HTTP headers in a hybrid data structure to provide
+    efficient insertions and lookups while preserving the original data.
+
+    In order to account for multiple values with minimal hassle,
+    :class:`Headers` follows this logic:
+
+    - When getting a header with ``headers[name]``:
+        - if there's no value, :exc:`KeyError` is raised;
+        - if there's exactly one value, it's returned;
+        - if there's more than one value, :exc:`MultipleValuesError` is raised.
+
+    - When setting a header with ``headers[name] = value``, the value is
+      appended to the list of values for that header.
+
+    - When deleting a header with ``del headers[name]``, all values for that
+      header are removed (this is slow).
+
+    Other methods for manipulating headers are consistent with this logic.
+
+    As long as no header occurs multiple times, :class:`Headers` behaves like
+    :class:`dict`, except keys are lower-cased to provide case-insensitivity.
+
+    Two methods support manipulating multiple values explicitly:
+
+    - :meth:`get_all` returns a list of all values for a header;
+    - :meth:`raw_items` returns an iterator of ``(name, values)`` pairs.
+
+    """
+
+    __slots__ = ["_dict", "_list"]
+
+    # Like dict, Headers accepts an optional "mapping or iterable" argument.
+    def __init__(self, *args: HeadersLike, **kwargs: str) -> None:
+        self._dict: dict[str, list[str]] = {}
+        self._list: list[tuple[str, str]] = []
+        self.update(*args, **kwargs)
+
+    def __str__(self) -> str:
+        return "".join(f"{key}: {value}\r\n" for key, value in self._list) + "\r\n"
+
+    def __repr__(self) -> str:
+        return f"{self.__class__.__name__}({self._list!r})"
+
+    def copy(self) -> Headers:
+        copy = self.__class__()
+        copy._dict = self._dict.copy()
+        copy._list = self._list.copy()
+        return copy
+
+    def serialize(self) -> bytes:
+        # Since headers only contain ASCII characters, we can keep this simple.
+        return str(self).encode()
+
+    # Collection methods
+
+    def __contains__(self, key: object) -> bool:
+        return isinstance(key, str) and key.lower() in self._dict
+
+    def __iter__(self) -> Iterator[str]:
+        return iter(self._dict)
+
+    def __len__(self) -> int:
+        return len(self._dict)
+
+    # MutableMapping methods
+
+    def __getitem__(self, key: str) -> str:
+        value = self._dict[key.lower()]
+        if len(value) == 1:
+            return value[0]
+        else:
+            raise MultipleValuesError(key)
+
+    def __setitem__(self, key: str, value: str) -> None:
+        self._dict.setdefault(key.lower(), []).append(value)
+        self._list.append((key, value))
+
+    def __delitem__(self, key: str) -> None:
+        key_lower = key.lower()
+        self._dict.__delitem__(key_lower)
+        # This is inefficient. Fortunately deleting HTTP headers is uncommon.
+        self._list = [(k, v) for k, v in self._list if k.lower() != key_lower]
+
+    def __eq__(self, other: Any) -> bool:
+        if not isinstance(other, Headers):
+            return NotImplemented
+        return self._dict == other._dict
+
+    def clear(self) -> None:
+        """
+        Remove all headers.
+
+        """
+        self._dict = {}
+        self._list = []
+
+    def update(self, *args: HeadersLike, **kwargs: str) -> None:
+        """
+        Update from a :class:`Headers` instance and/or keyword arguments.
+
+        """
+        args = tuple(
+            arg.raw_items() if isinstance(arg, Headers) else arg for arg in args
+        )
+        super().update(*args, **kwargs)
+
+    # Methods for handling multiple values
+
+    def get_all(self, key: str) -> list[str]:
+        """
+        Return the (possibly empty) list of all values for a header.
+
+        Args:
+            key: Header name.
+
+        """
+        return self._dict.get(key.lower(), [])
+
+    def raw_items(self) -> Iterator[tuple[str, str]]:
+        """
+        Return an iterator of all values as ``(name, value)`` pairs.
+
+        """
+        return iter(self._list)
+
+
+# copy of _typeshed.SupportsKeysAndGetItem.
+class SupportsKeysAndGetItem(Protocol):  # pragma: no cover
+    """
+    Dict-like types with ``keys() -> str`` and ``__getitem__(key: str) -> str`` methods.
+
+    """
+
+    def keys(self) -> Iterable[str]: ...
+
+    def __getitem__(self, key: str) -> str: ...
+
+
+# Change to Headers | Mapping[str, str] | ... when dropping Python < 3.10.
+HeadersLike = Union[
+    Headers,
+    Mapping[str, str],
+    Iterable[tuple[str, str]],
+    SupportsKeysAndGetItem,
+]
+"""
+Types accepted where :class:`Headers` is expected.
+
+In addition to :class:`Headers` itself, this includes dict-like types where both
+keys and values are :class:`str`.
+
+"""