add type hints to all of the code

In order to use type hint syntax, we need to bump the minimum Python
version to 3.7 and some of the features such as Literal and Protocol are
opted in when a sufficiently recent Python is available.

This does not make all of the code pass type checking with mypy. A
number of typing issues remain, but the output of mypy becomes something
one can read through.

In adding type hints, a lot of epydoc @type annotations are removed as
redundant. This update also adopts black-style line breaking.

1 files changed, 29 insertions, 15 deletions

diff --git a/wsgitools/applications.py b/wsgitools/applications.py
index 9894cf8..f51fccf 100644
--- a/wsgitools/applications.py
+++ b/wsgitools/applications.py
@@ -1,4 +1,7 @@
 import os.path
+import typing
+
+from wsgitools.internal import Environ, HeaderList, StartResponse
 
 __all__ = []
 
@@ -9,17 +12,21 @@ class StaticContent:
     receives with method GET or HEAD (content stripped). If not present, a
     content-length header is computed.
     """
-    def __init__(self, status, headers, content, anymethod=False):
+    content: typing.Iterable[bytes]
+
+    def __init__(
+        self,
+        status: str,
+        headers: HeaderList,
+        content: typing.Union[bytes, typing.Iterable[bytes]],
+        anymethod: bool = False,
+    ):
         """
-        @type status: str
         @param status: is the HTTP status returned to the browser (ex: "200 OK")
-        @type headers: list
         @param headers: is a list of C{(header, value)} pairs being delivered as
                 HTTP headers
-        @type content: bytes
         @param content: contains the data to be delivered to the client. It is
                 either a string or some kind of iterable yielding strings.
-        @type anymethod: boolean
         @param anymethod: determines whether any request method should be
                 answered with this response instead of a 501
         """
@@ -40,7 +47,9 @@ class StaticContent:
         if length >= 0:
             if  not [v for h, v in headers if h.lower() == "content-length"]:
                 headers.append(("Content-length", str(length)))
-    def __call__(self, environ, start_response):
+    def __call__(
+        self, environ: Environ, start_response: StartResponse
+    ) -> typing.Iterable[bytes]:
         """wsgi interface"""
         assert isinstance(environ, dict)
         if environ["REQUEST_METHOD"].upper() not in ["GET", "HEAD"] and \
@@ -61,20 +70,21 @@ class StaticFile:
     request it receives with method GET or HEAD (content stripped). If not
     present, a content-length header is computed.
     """
-    def __init__(self, filelike, status="200 OK", headers=list(),
-                 blocksize=4096):
+    def __init__(
+        self,
+        filelike: typing.Union[str, typing.BinaryIO],
+        status: str = "200 OK",
+        headers: HeaderList = list(),
+        blocksize: int = 4096,
+    ):
         """
-        @type status: str
         @param status: is the HTTP status returned to the browser
-        @type headers: [(str, str)]
         @param headers: is a list of C{(header, value)} pairs being delivered as
                 HTTP headers
-        @type filelike: str or file-like
         @param filelike: may either be an path in the local file system or a
                 file-like that must support C{read(size)} and C{seek(0)}. If
                 C{tell()} is present, C{seek(0, 2)} and C{tell()} will be used
                 to compute the content-length.
-        @type blocksize: int
         @param blocksize: the content is provided in chunks of this size
         """
         self.filelike = filelike
@@ -82,7 +92,9 @@ class StaticFile:
         self.headers = headers
         self.blocksize = blocksize
 
-    def _serve_in_chunks(self, stream):
+    def _serve_in_chunks(
+        self, stream: typing.BinaryIO
+    ) -> typing.Iterator[bytes]:
         """internal method yielding data from the given stream"""
         while True:
             data = stream.read(self.blocksize)
@@ -92,7 +104,9 @@ class StaticFile:
         if isinstance(self.filelike, str):
             stream.close()
 
-    def __call__(self, environ, start_response):
+    def __call__(
+        self, environ: Environ, start_response: StartResponse
+    ) -> typing.Iterable[bytes]:
         """wsgi interface"""
         assert isinstance(environ, dict)
 
@@ -102,7 +116,7 @@ class StaticFile:
                            [("Content-length", str(len(resp)))])
             return [resp]
 
-        stream = None
+        stream: typing.Optional[typing.BinaryIO] = None
         size = -1
         try:
             if isinstance(self.filelike, str):