Rework the mechanisms for async GnuTLS connections

* lisp/net/gnutls.el (open-gnutls-stream): Compute the
gnutls-boot parameters and pass them to the process object.
(gnutls-negotiate): New parameter :return-keywords that won't
connect to anything, just compute the keywords.

* lisp/url/url-http.el (url-http): Revert async TLS sentinel
hack, which is no longer necessary.

* src/gnutls.c (Fgnutls_asynchronous_parameters): Rename from
gnutls-mark-process.

* src/process.c (connect_network_socket): If we're connecting to
an asynchronous TLS socket, complete the GnuTLS boot sequence here.

* src/process.h: New parameter gnutls_async_parameters.

3 files changed, 21 insertions, 7 deletions

diff --git a/src/gnutls.c b/src/gnutls.c
index d11b11c7c54..06459fb3ccd 100644
--- a/src/gnutls.c
+++ b/src/gnutls.c
@@ -686,13 +686,16 @@ emacs_gnutls_deinit (Lisp_Object proc)
   return Qt;
 }
 
-DEFUN ("gnutls-mark-process", Fgnutls_mark_process, Sgnutls_mark_process, 2, 2, 0,
-       doc: /* Mark this process as being a pre-init GnuTLS process.  */)
-  (Lisp_Object proc, Lisp_Object state)
+DEFUN ("gnutls-asynchronous-parameters", Fgnutls_asynchronous_parameters,
+       Sgnutls_asynchronous_parameters, 2, 2, 0,
+       doc: /* Mark this process as being a pre-init GnuTLS process.
+The second parameter is the list of parameters to feed to gnutls-boot
+to finish setting up the connection. */)
+  (Lisp_Object proc, Lisp_Object params)
 {
   CHECK_PROCESS (proc);
 
-  XPROCESS (proc)->gnutls_wait_p = !NILP (state);
+  XPROCESS (proc)->gnutls_async_parameters = params;
   return Qnil;
 }
 
@@ -1703,7 +1706,7 @@ syms_of_gnutls (void)
         make_number (GNUTLS_E_APPLICATION_ERROR_MIN));
 
   defsubr (&Sgnutls_get_initstage);
-  defsubr (&Sgnutls_mark_process);
+  defsubr (&Sgnutls_asynchronous_parameters);
   defsubr (&Sgnutls_errorp);
   defsubr (&Sgnutls_error_fatalp);
   defsubr (&Sgnutls_error_string);
diff --git a/src/process.c b/src/process.c
index a30dd23077c..55264058340 100644
--- a/src/process.c
+++ b/src/process.c
@@ -715,6 +715,7 @@ make_process (Lisp_Object name)
 
 #ifdef HAVE_GNUTLS
   p->gnutls_initstage = GNUTLS_STAGE_EMPTY;
+  p->gnutls_async_parameters = Qnil;
 #endif
 
   /* If name is already in use, modify it until it is unused.  */
@@ -3305,6 +3306,14 @@ void connect_network_socket (Lisp_Object proc, Lisp_Object ip_addresses)
     max_process_desc = inch;
 
   set_network_socket_coding_system (proc);
+
+#ifdef HAVE_GNUTLS
+  if (!NILP (p->gnutls_async_parameters) && p->is_non_blocking_client) {
+    Fgnutls_boot (proc, Fcar (p->gnutls_async_parameters),
+                  Fcdr (p->gnutls_async_parameters));
+    p->gnutls_async_parameters = Qnil;
+  }
+#endif
 }
 
 
@@ -5817,7 +5826,9 @@ send_process (Lisp_Object proc, const char *buf, ptrdiff_t len,
     error ("Output file descriptor of %s is closed", SDATA (p->name));
 
 #ifdef HAVE_GNUTLS
-  if (p->gnutls_wait_p)
+  /* The TLS connection hasn't been set up yet, so we can't write
+     anything on the socket. */
+  if (p->gnutls_async_parameters)
     return;
 #endif
 
diff --git a/src/process.h b/src/process.h
index 8bd555b83bd..eb34f5f0411 100644
--- a/src/process.h
+++ b/src/process.h
@@ -191,8 +191,8 @@ struct Lisp_Process
     unsigned int gnutls_extra_peer_verification;
     int gnutls_log_level;
     int gnutls_handshakes_tried;
+    Lisp_Object gnutls_async_parameters;
     bool_bf gnutls_p : 1;
-    bool_bf gnutls_wait_p : 1;
 #endif
 };