alekstorm/tornado forked from tornadoweb/tornado

* TLS NPN means that one of many protocols can be selected after a TCP connection is established. A
  layer of indirection was added to TCPServer to allow it to delegate handling of a TCP connection
  to whichever protocol handler was negotiated. If the `npn_protocols` parameter (a list of
  (name, handler) tuples in order of preference) was passed to the constructor, the connection is
  over TLS, and NPN succeeded, the handler for the chosen name will be called. Otherwise, the
  `protocol` constructor parameter will be called. For example, SPDYServer is essentially:

  class SPDYServer(TCPServer):
      def __init__(self, request_callback):
          http_protocol = HTTPServerProtocol(request_callback)
          TCPServer.__init__(self, http_protocol,
              npn_protocols=[
                  ('spdy/2', SPDYServerProtocol(request_callback)),
                  ('http/1.1', http_protocol)])

* TCPServer was moved from netutil to its own module, tcpserver.

* Since utilizing NPN support in Python 3.3 requires the `ssl.SSLContext` class, which isn't
  available in Python 2.x, the wrap_socket() top-level function was added to `netutil` to abstract
  away these details. In addition, the `SUPPORTS_NPN` constant was added as a convenience for
  determining if the system supported NPN.

* Previously, `web.RequestHandler` formatted the HTTP response itself and wrote it directly to the
  IOStream. This responsibility has been moved to the HTTPRequest.connection object, which must
  provide the write_preamble() and write() methods - the former writes the response status line and
  headers, while the latter writes a chunk of the response body.

* Although IOStream.connect() already takes a callback parameter, in SSLIOStream it's not called
  until the SSL handshake is completed (which contains TLS NPN) - and TCPServer, which doesn't call
  connect(), won't know which protocol handler to execute until that happens. To fix this, a
  set_connect_callback method was added to IOStream.

* Snippets that conditionally imported BytesIO and ssl were moved into util and netutil,
  respectively. These symbols are now imported from there.

Restore context for all read methods

Prior to 2db0ace this was being done
properly, but the refactor removed stack_context.wrap causing some issues
in our upstream context managers.

These lines are not reached, but if they were they would fail with
a less clear message than intended.

Closes #520.

Closes #494.

Now HTTPConnection.address will always be the socket address,
and the fake "0.0.0.0" IP is only used in contexts that want an IP
(i.e. HTTPRequest.remote_ip) but the connection is a non-IP socket.

Better connection check in RequestHandler

Closes #519.

Closes #515.

Closes #489.

Internally, StackContexts now return a deactivation callback,
which can be used to prevent that StackContext from propagating
further.  This is used in gen.engine because the decorator doesn't know
which arguments are callbacks that need to be wrapped outside of its
ExceptionStackContext.  This is deliberately undocumented for now.

Closes #507.

Modified linkify to accept a callable for extra_params.

Closes #506.

This is required by the RFC as it may confuse caches.

This is needed for correct support of the 304 status code, which
has no body and should not have either a Content-Length or
Transfer-Encoding.  This is a backwards-incompatible change to an
interface that was never technically private, but not included in the
documentation and as far as I can tell was never used outside
tornado itself.

A new release of zope.interface breaks things on python 2.5, and
sets off our (overly-sensitive?) deprecation checking.

Cleaned up the few windows-specific bits of code.  The socket-based
Waker is also usable on Jython.

version from testing.py, which works better with 2to3.

Closes #508

urlparse.urlsplit expects a full url, but we were using it for a bare path.
This mostly worked but would parse paths beginning with "//" incorrectly.
Fortunately all we really need to do is split the path on "?".

Closes #509.