hgweb: make parsedrequest part of wsgirequest

hgweb: make parsedrequest part of wsgirequest

This is kind of ugly. But an upcoming commit will teach parsedrequest
about the input stream. Because the input stream is global state and
can't be accessed without side-effects, we need to take actions to
ensure that multiple consumers don't read from it independently. The
easiest way to do this is for one object to hold a reference to both
items having access to the input stream so that when a copy is made,
we can remove the attribute from the other instance.

So we create our parsed request instance from the wsgirequest
constructor and hold a reference to it there. This is better than
our new type holding a reference to wsgirequest because all the
code for managing access will be temporary and we shouldn't pollute
parsedrequest with this ugly history.

Differential Revision: https://phab.mercurial-scm.org/D2770

--- a/mercurial/hgweb/hgweb_mod.py	Sat Mar 10 11:03:45 2018 -0800
+++ b/mercurial/hgweb/hgweb_mod.py	Sat Mar 10 10:56:10 2018 -0800
@@ -304,7 +304,7 @@
                     yield r
 
     def _runwsgi(self, wsgireq, repo):
-        req = requestmod.parserequestfromenv(wsgireq.env)
+        req = wsgireq.req
         rctx = requestcontext(self, repo)
 
         # This state is global across all threads.

--- a/mercurial/hgweb/hgwebdir_mod.py	Sat Mar 10 11:03:45 2018 -0800
+++ b/mercurial/hgweb/hgwebdir_mod.py	Sat Mar 10 10:56:10 2018 -0800
@@ -287,6 +287,11 @@
                 real = repos.get(virtualrepo)
                 if real:
                     wsgireq.env['REPO_NAME'] = virtualrepo
+                    # We have to re-parse because of updated environment
+                    # variable.
+                    # TODO this is kind of hacky and we should have a better
+                    # way of doing this than with REPO_NAME side-effects.
+                    wsgireq.req = requestmod.parserequestfromenv(wsgireq.env)
                     try:
                         # ensure caller gets private copy of ui
                         repo = hg.repository(self.ui.copy(), real)

--- a/mercurial/hgweb/request.py	Sat Mar 10 11:03:45 2018 -0800
+++ b/mercurial/hgweb/request.py	Sat Mar 10 10:56:10 2018 -0800
@@ -254,6 +254,8 @@
         self.server_write = None
         self.headers = []
 
+        self.req = parserequestfromenv(wsgienv)
+
     def respond(self, status, type, filename=None, body=None):
         if not isinstance(type, str):
             type = pycompat.sysstr(type)