done

lib/python3.11/site-packages/werkzeug/datastructures/range.py

@@ -0,0 +1,214 @@
+from __future__ import annotations
+
+import collections.abc as cabc
+import typing as t
+from datetime import datetime
+
+if t.TYPE_CHECKING:
+    import typing_extensions as te
+
+T = t.TypeVar("T")
+
+
+class IfRange:
+    """Very simple object that represents the `If-Range` header in parsed
+    form.  It will either have neither a etag or date or one of either but
+    never both.
+
+    .. versionadded:: 0.7
+    """
+
+    def __init__(self, etag: str | None = None, date: datetime | None = None):
+        #: The etag parsed and unquoted.  Ranges always operate on strong
+        #: etags so the weakness information is not necessary.
+        self.etag = etag
+        #: The date in parsed format or `None`.
+        self.date = date
+
+    def to_header(self) -> str:
+        """Converts the object back into an HTTP header."""
+        if self.date is not None:
+            return http.http_date(self.date)
+        if self.etag is not None:
+            return http.quote_etag(self.etag)
+        return ""
+
+    def __str__(self) -> str:
+        return self.to_header()
+
+    def __repr__(self) -> str:
+        return f"<{type(self).__name__} {str(self)!r}>"
+
+
+class Range:
+    """Represents a ``Range`` header. All methods only support only
+    bytes as the unit. Stores a list of ranges if given, but the methods
+    only work if only one range is provided.
+
+    :raise ValueError: If the ranges provided are invalid.
+
+    .. versionchanged:: 0.15
+        The ranges passed in are validated.
+
+    .. versionadded:: 0.7
+    """
+
+    def __init__(
+        self, units: str, ranges: cabc.Sequence[tuple[int, int | None]]
+    ) -> None:
+        #: The units of this range.  Usually "bytes".
+        self.units = units
+        #: A list of ``(begin, end)`` tuples for the range header provided.
+        #: The ranges are non-inclusive.
+        self.ranges = ranges
+
+        for start, end in ranges:
+            if start is None or (end is not None and (start < 0 or start >= end)):
+                raise ValueError(f"{(start, end)} is not a valid range.")
+
+    def range_for_length(self, length: int | None) -> tuple[int, int] | None:
+        """If the range is for bytes, the length is not None and there is
+        exactly one range and it is satisfiable it returns a ``(start, stop)``
+        tuple, otherwise `None`.
+        """
+        if self.units != "bytes" or length is None or len(self.ranges) != 1:
+            return None
+        start, end = self.ranges[0]
+        if end is None:
+            end = length
+            if start < 0:
+                start += length
+        if http.is_byte_range_valid(start, end, length):
+            return start, min(end, length)
+        return None
+
+    def make_content_range(self, length: int | None) -> ContentRange | None:
+        """Creates a :class:`~werkzeug.datastructures.ContentRange` object
+        from the current range and given content length.
+        """
+        rng = self.range_for_length(length)
+        if rng is not None:
+            return ContentRange(self.units, rng[0], rng[1], length)
+        return None
+
+    def to_header(self) -> str:
+        """Converts the object back into an HTTP header."""
+        ranges = []
+        for begin, end in self.ranges:
+            if end is None:
+                ranges.append(f"{begin}-" if begin >= 0 else str(begin))
+            else:
+                ranges.append(f"{begin}-{end - 1}")
+        return f"{self.units}={','.join(ranges)}"
+
+    def to_content_range_header(self, length: int | None) -> str | None:
+        """Converts the object into `Content-Range` HTTP header,
+        based on given length
+        """
+        range = self.range_for_length(length)
+        if range is not None:
+            return f"{self.units} {range[0]}-{range[1] - 1}/{length}"
+        return None
+
+    def __str__(self) -> str:
+        return self.to_header()
+
+    def __repr__(self) -> str:
+        return f"<{type(self).__name__} {str(self)!r}>"
+
+
+class _CallbackProperty(t.Generic[T]):
+    def __set_name__(self, owner: type[ContentRange], name: str) -> None:
+        self.attr = f"_{name}"
+
+    @t.overload
+    def __get__(self, instance: None, owner: None) -> te.Self: ...
+    @t.overload
+    def __get__(self, instance: ContentRange, owner: type[ContentRange]) -> T: ...
+    def __get__(
+        self, instance: ContentRange | None, owner: type[ContentRange] | None
+    ) -> te.Self | T:
+        if instance is None:
+            return self
+
+        return instance.__dict__[self.attr]  # type: ignore[no-any-return]
+
+    def __set__(self, instance: ContentRange, value: T) -> None:
+        instance.__dict__[self.attr] = value
+
+        if instance.on_update is not None:
+            instance.on_update(instance)
+
+
+class ContentRange:
+    """Represents the content range header.
+
+    .. versionadded:: 0.7
+    """
+
+    def __init__(
+        self,
+        units: str | None,
+        start: int | None,
+        stop: int | None,
+        length: int | None = None,
+        on_update: cabc.Callable[[ContentRange], None] | None = None,
+    ) -> None:
+        self.on_update = on_update
+        self.set(start, stop, length, units)
+
+    #: The units to use, usually "bytes"
+    units: str | None = _CallbackProperty()  # type: ignore[assignment]
+    #: The start point of the range or `None`.
+    start: int | None = _CallbackProperty()  # type: ignore[assignment]
+    #: The stop point of the range (non-inclusive) or `None`.  Can only be
+    #: `None` if also start is `None`.
+    stop: int | None = _CallbackProperty()  # type: ignore[assignment]
+    #: The length of the range or `None`.
+    length: int | None = _CallbackProperty()  # type: ignore[assignment]
+
+    def set(
+        self,
+        start: int | None,
+        stop: int | None,
+        length: int | None = None,
+        units: str | None = "bytes",
+    ) -> None:
+        """Simple method to update the ranges."""
+        assert http.is_byte_range_valid(start, stop, length), "Bad range provided"
+        self._units: str | None = units
+        self._start: int | None = start
+        self._stop: int | None = stop
+        self._length: int | None = length
+        if self.on_update is not None:
+            self.on_update(self)
+
+    def unset(self) -> None:
+        """Sets the units to `None` which indicates that the header should
+        no longer be used.
+        """
+        self.set(None, None, units=None)
+
+    def to_header(self) -> str:
+        if self._units is None:
+            return ""
+        if self._length is None:
+            length: str | int = "*"
+        else:
+            length = self._length
+        if self._start is None:
+            return f"{self._units} */{length}"
+        return f"{self._units} {self._start}-{self._stop - 1}/{length}"  # type: ignore[operator]
+
+    def __bool__(self) -> bool:
+        return self._units is not None
+
+    def __str__(self) -> str:
+        return self.to_header()
+
+    def __repr__(self) -> str:
+        return f"<{type(self).__name__} {str(self)!r}>"
+
+
+# circular dependencies
+from .. import http