1 files changed, 247 insertions, 0 deletions

diff --git a/venv/lib/python3.9/site-packages/h11/_readers.py b/venv/lib/python3.9/site-packages/h11/_readers.py
new file mode 100644
index 00000000..08a9574d
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/h11/_readers.py
@@ -0,0 +1,247 @@
+# Code to read HTTP data
+#
+# Strategy: each reader is a callable which takes a ReceiveBuffer object, and
+# either:
+# 1) consumes some of it and returns an Event
+# 2) raises a LocalProtocolError (for consistency -- e.g. we call validate()
+#    and it might raise a LocalProtocolError, so simpler just to always use
+#    this)
+# 3) returns None, meaning "I need more data"
+#
+# If they have a .read_eof attribute, then this will be called if an EOF is
+# received -- but this is optional. Either way, the actual ConnectionClosed
+# event will be generated afterwards.
+#
+# READERS is a dict describing how to pick a reader. It maps states to either:
+# - a reader
+# - or, for body readers, a dict of per-framing reader factories
+
+import re
+from typing import Any, Callable, Dict, Iterable, NoReturn, Optional, Tuple, Type, Union
+
+from ._abnf import chunk_header, header_field, request_line, status_line
+from ._events import Data, EndOfMessage, InformationalResponse, Request, Response
+from ._receivebuffer import ReceiveBuffer
+from ._state import (
+    CLIENT,
+    CLOSED,
+    DONE,
+    IDLE,
+    MUST_CLOSE,
+    SEND_BODY,
+    SEND_RESPONSE,
+    SERVER,
+)
+from ._util import LocalProtocolError, RemoteProtocolError, Sentinel, validate
+
+__all__ = ["READERS"]
+
+header_field_re = re.compile(header_field.encode("ascii"))
+obs_fold_re = re.compile(rb"[ \t]+")
+
+
+def _obsolete_line_fold(lines: Iterable[bytes]) -> Iterable[bytes]:
+    it = iter(lines)
+    last: Optional[bytes] = None
+    for line in it:
+        match = obs_fold_re.match(line)
+        if match:
+            if last is None:
+                raise LocalProtocolError("continuation line at start of headers")
+            if not isinstance(last, bytearray):
+                # Cast to a mutable type, avoiding copy on append to ensure O(n) time
+                last = bytearray(last)
+            last += b" "
+            last += line[match.end() :]
+        else:
+            if last is not None:
+                yield last
+            last = line
+    if last is not None:
+        yield last
+
+
+def _decode_header_lines(
+    lines: Iterable[bytes],
+) -> Iterable[Tuple[bytes, bytes]]:
+    for line in _obsolete_line_fold(lines):
+        matches = validate(header_field_re, line, "illegal header line: {!r}", line)
+        yield (matches["field_name"], matches["field_value"])
+
+
+request_line_re = re.compile(request_line.encode("ascii"))
+
+
+def maybe_read_from_IDLE_client(buf: ReceiveBuffer) -> Optional[Request]:
+    lines = buf.maybe_extract_lines()
+    if lines is None:
+        if buf.is_next_line_obviously_invalid_request_line():
+            raise LocalProtocolError("illegal request line")
+        return None
+    if not lines:
+        raise LocalProtocolError("no request line received")
+    matches = validate(
+        request_line_re, lines[0], "illegal request line: {!r}", lines[0]
+    )
+    return Request(
+        headers=list(_decode_header_lines(lines[1:])), _parsed=True, **matches
+    )
+
+
+status_line_re = re.compile(status_line.encode("ascii"))
+
+
+def maybe_read_from_SEND_RESPONSE_server(
+    buf: ReceiveBuffer,
+) -> Union[InformationalResponse, Response, None]:
+    lines = buf.maybe_extract_lines()
+    if lines is None:
+        if buf.is_next_line_obviously_invalid_request_line():
+            raise LocalProtocolError("illegal request line")
+        return None
+    if not lines:
+        raise LocalProtocolError("no response line received")
+    matches = validate(status_line_re, lines[0], "illegal status line: {!r}", lines[0])
+    http_version = (
+        b"1.1" if matches["http_version"] is None else matches["http_version"]
+    )
+    reason = b"" if matches["reason"] is None else matches["reason"]
+    status_code = int(matches["status_code"])
+    class_: Union[Type[InformationalResponse], Type[Response]] = (
+        InformationalResponse if status_code < 200 else Response
+    )
+    return class_(
+        headers=list(_decode_header_lines(lines[1:])),
+        _parsed=True,
+        status_code=status_code,
+        reason=reason,
+        http_version=http_version,
+    )
+
+
+class ContentLengthReader:
+    def __init__(self, length: int) -> None:
+        self._length = length
+        self._remaining = length
+
+    def __call__(self, buf: ReceiveBuffer) -> Union[Data, EndOfMessage, None]:
+        if self._remaining == 0:
+            return EndOfMessage()
+        data = buf.maybe_extract_at_most(self._remaining)
+        if data is None:
+            return None
+        self._remaining -= len(data)
+        return Data(data=data)
+
+    def read_eof(self) -> NoReturn:
+        raise RemoteProtocolError(
+            "peer closed connection without sending complete message body "
+            "(received {} bytes, expected {})".format(
+                self._length - self._remaining, self._length
+            )
+        )
+
+
+chunk_header_re = re.compile(chunk_header.encode("ascii"))
+
+
+class ChunkedReader:
+    def __init__(self) -> None:
+        self._bytes_in_chunk = 0
+        # After reading a chunk, we have to throw away the trailing \r\n; if
+        # this is >0 then we discard that many bytes before resuming regular
+        # de-chunkification.
+        self._bytes_to_discard = 0
+        self._reading_trailer = False
+
+    def __call__(self, buf: ReceiveBuffer) -> Union[Data, EndOfMessage, None]:
+        if self._reading_trailer:
+            lines = buf.maybe_extract_lines()
+            if lines is None:
+                return None
+            return EndOfMessage(headers=list(_decode_header_lines(lines)))
+        if self._bytes_to_discard > 0:
+            data = buf.maybe_extract_at_most(self._bytes_to_discard)
+            if data is None:
+                return None
+            self._bytes_to_discard -= len(data)
+            if self._bytes_to_discard > 0:
+                return None
+            # else, fall through and read some more
+        assert self._bytes_to_discard == 0
+        if self._bytes_in_chunk == 0:
+            # We need to refill our chunk count
+            chunk_header = buf.maybe_extract_next_line()
+            if chunk_header is None:
+                return None
+            matches = validate(
+                chunk_header_re,
+                chunk_header,
+                "illegal chunk header: {!r}",
+                chunk_header,
+            )
+            # XX FIXME: we discard chunk extensions. Does anyone care?
+            self._bytes_in_chunk = int(matches["chunk_size"], base=16)
+            if self._bytes_in_chunk == 0:
+                self._reading_trailer = True
+                return self(buf)
+            chunk_start = True
+        else:
+            chunk_start = False
+        assert self._bytes_in_chunk > 0
+        data = buf.maybe_extract_at_most(self._bytes_in_chunk)
+        if data is None:
+            return None
+        self._bytes_in_chunk -= len(data)
+        if self._bytes_in_chunk == 0:
+            self._bytes_to_discard = 2
+            chunk_end = True
+        else:
+            chunk_end = False
+        return Data(data=data, chunk_start=chunk_start, chunk_end=chunk_end)
+
+    def read_eof(self) -> NoReturn:
+        raise RemoteProtocolError(
+            "peer closed connection without sending complete message body "
+            "(incomplete chunked read)"
+        )
+
+
+class Http10Reader:
+    def __call__(self, buf: ReceiveBuffer) -> Optional[Data]:
+        data = buf.maybe_extract_at_most(999999999)
+        if data is None:
+            return None
+        return Data(data=data)
+
+    def read_eof(self) -> EndOfMessage:
+        return EndOfMessage()
+
+
+def expect_nothing(buf: ReceiveBuffer) -> None:
+    if buf:
+        raise LocalProtocolError("Got data when expecting EOF")
+    return None
+
+
+ReadersType = Dict[
+    Union[Type[Sentinel], Tuple[Type[Sentinel], Type[Sentinel]]],
+    Union[Callable[..., Any], Dict[str, Callable[..., Any]]],
+]
+
+READERS: ReadersType = {
+    (CLIENT, IDLE): maybe_read_from_IDLE_client,
+    (SERVER, IDLE): maybe_read_from_SEND_RESPONSE_server,
+    (SERVER, SEND_RESPONSE): maybe_read_from_SEND_RESPONSE_server,
+    (CLIENT, DONE): expect_nothing,
+    (CLIENT, MUST_CLOSE): expect_nothing,
+    (CLIENT, CLOSED): expect_nothing,
+    (SERVER, DONE): expect_nothing,
+    (SERVER, MUST_CLOSE): expect_nothing,
+    (SERVER, CLOSED): expect_nothing,
+    SEND_BODY: {
+        "chunked": ChunkedReader,
+        "content-length": ContentLengthReader,
+        "http/1.0": Http10Reader,
+    },
+}