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stbi/Lib/site-packages/pip/_vendor/cachecontrol/serialize.py

+import base64
+import io
+import json
+import zlib
+
+from pip._vendor import msgpack
+from pip._vendor.requests.structures import CaseInsensitiveDict
+
+from .compat import HTTPResponse, pickle, text_type
+
+
+def _b64_decode_bytes(b):
+    return base64.b64decode(b.encode("ascii"))
+
+
+def _b64_decode_str(s):
+    return _b64_decode_bytes(s).decode("utf8")
+
+
+class Serializer(object):
+
+    def dumps(self, request, response, body=None):
+        response_headers = CaseInsensitiveDict(response.headers)
+
+        if body is None:
+            body = response.read(decode_content=False)
+
+            # NOTE: 99% sure this is dead code. I'm only leaving it
+            #       here b/c I don't have a test yet to prove
+            #       it. Basically, before using
+            #       `cachecontrol.filewrapper.CallbackFileWrapper`,
+            #       this made an effort to reset the file handle. The
+            #       `CallbackFileWrapper` short circuits this code by
+            #       setting the body as the content is consumed, the
+            #       result being a `body` argument is *always* passed
+            #       into cache_response, and in turn,
+            #       `Serializer.dump`.
+            response._fp = io.BytesIO(body)
+
+        # NOTE: This is all a bit weird, but it's really important that on
+        #       Python 2.x these objects are unicode and not str, even when
+        #       they contain only ascii. The problem here is that msgpack
+        #       understands the difference between unicode and bytes and we
+        #       have it set to differentiate between them, however Python 2
+        #       doesn't know the difference. Forcing these to unicode will be
+        #       enough to have msgpack know the difference.
+        data = {
+            u"response": {
+                u"body": body,
+                u"headers": dict(
+                    (text_type(k), text_type(v)) for k, v in response.headers.items()
+                ),
+                u"status": response.status,
+                u"version": response.version,
+                u"reason": text_type(response.reason),
+                u"strict": response.strict,
+                u"decode_content": response.decode_content,
+            }
+        }
+
+        # Construct our vary headers
+        data[u"vary"] = {}
+        if u"vary" in response_headers:
+            varied_headers = response_headers[u"vary"].split(",")
+            for header in varied_headers:
+                header = text_type(header).strip()
+                header_value = request.headers.get(header, None)
+                if header_value is not None:
+                    header_value = text_type(header_value)
+                data[u"vary"][header] = header_value
+
+        return b",".join([b"cc=4", msgpack.dumps(data, use_bin_type=True)])
+
+    def loads(self, request, data):
+        # Short circuit if we've been given an empty set of data
+        if not data:
+            return
+
+        # Determine what version of the serializer the data was serialized
+        # with
+        try:
+            ver, data = data.split(b",", 1)
+        except ValueError:
+            ver = b"cc=0"
+
+        # Make sure that our "ver" is actually a version and isn't a false
+        # positive from a , being in the data stream.
+        if ver[:3] != b"cc=":
+            data = ver + data
+            ver = b"cc=0"
+
+        # Get the version number out of the cc=N
+        ver = ver.split(b"=", 1)[-1].decode("ascii")
+
+        # Dispatch to the actual load method for the given version
+        try:
+            return getattr(self, "_loads_v{}".format(ver))(request, data)
+
+        except AttributeError:
+            # This is a version we don't have a loads function for, so we'll
+            # just treat it as a miss and return None
+            return
+
+    def prepare_response(self, request, cached):
+        """Verify our vary headers match and construct a real urllib3
+        HTTPResponse object.
+        """
+        # Special case the '*' Vary value as it means we cannot actually
+        # determine if the cached response is suitable for this request.
+        # This case is also handled in the controller code when creating
+        # a cache entry, but is left here for backwards compatibility.
+        if "*" in cached.get("vary", {}):
+            return
+
+        # Ensure that the Vary headers for the cached response match our
+        # request
+        for header, value in cached.get("vary", {}).items():
+            if request.headers.get(header, None) != value:
+                return
+
+        body_raw = cached["response"].pop("body")
+
+        headers = CaseInsensitiveDict(data=cached["response"]["headers"])
+        if headers.get("transfer-encoding", "") == "chunked":
+            headers.pop("transfer-encoding")
+
+        cached["response"]["headers"] = headers
+
+        try:
+            body = io.BytesIO(body_raw)
+        except TypeError:
+            # This can happen if cachecontrol serialized to v1 format (pickle)
+            # using Python 2. A Python 2 str(byte string) will be unpickled as
+            # a Python 3 str (unicode string), which will cause the above to
+            # fail with:
+            #
+            #     TypeError: 'str' does not support the buffer interface
+            body = io.BytesIO(body_raw.encode("utf8"))
+
+        return HTTPResponse(body=body, preload_content=False, **cached["response"])
+
+    def _loads_v0(self, request, data):
+        # The original legacy cache data. This doesn't contain enough
+        # information to construct everything we need, so we'll treat this as
+        # a miss.
+        return
+
+    def _loads_v1(self, request, data):
+        try:
+            cached = pickle.loads(data)
+        except ValueError:
+            return
+
+        return self.prepare_response(request, cached)
+
+    def _loads_v2(self, request, data):
+        try:
+            cached = json.loads(zlib.decompress(data).decode("utf8"))
+        except (ValueError, zlib.error):
+            return
+
+        # We need to decode the items that we've base64 encoded
+        cached["response"]["body"] = _b64_decode_bytes(cached["response"]["body"])
+        cached["response"]["headers"] = dict(
+            (_b64_decode_str(k), _b64_decode_str(v))
+            for k, v in cached["response"]["headers"].items()
+        )
+        cached["response"]["reason"] = _b64_decode_str(cached["response"]["reason"])
+        cached["vary"] = dict(
+            (_b64_decode_str(k), _b64_decode_str(v) if v is not None else v)
+            for k, v in cached["vary"].items()
+        )
+
+        return self.prepare_response(request, cached)
+
+    def _loads_v3(self, request, data):
+        # Due to Python 2 encoding issues, it's impossible to know for sure
+        # exactly how to load v3 entries, thus we'll treat these as a miss so
+        # that they get rewritten out as v4 entries.
+        return
+
+    def _loads_v4(self, request, data):
+        try:
+            cached = msgpack.loads(data, raw=False)
+        except ValueError:
+            return
+
+        return self.prepare_response(request, cached)