Switch to cow_http2_machine for HTTP/2

A common state machine for Gun and Cowboy will be easier to
maintain. This fixes numerous issues including some test
failures that were hidden because the h2specd_SUITE was
flawed.

We temporarily depend on Cowlib master until a new version
is released.

Makefile

@@ -13,7 +13,7 @@ CT_OPTS += -pa test -ct_hooks gun_ct_hook [] # -boot start_sasl
 LOCAL_DEPS = ssl
 
 DEPS = cowlib
-dep_cowlib = git https://github.com/ninenines/cowlib 2.6.0
+dep_cowlib = git https://github.com/ninenines/cowlib master
 
 DOC_DEPS = asciideck
 

rebar.config

@@ -1,4 +1,4 @@
 {deps, [
-{cowlib,".*",{git,"https://github.com/ninenines/cowlib","2.6.0"}}
+{cowlib,".*",{git,"https://github.com/ninenines/cowlib","master"}}
 ]}.
 {erl_opts, [debug_info,warn_export_vars,warn_shadow_vars,warn_obsolete_guard]}.

src/gun.erl

@@ -845,6 +845,9 @@ loop(State=#state{parent=Parent, owner=Owner, owner_ref=OwnerRef,
 		{system, From, Request} ->
 			sys:handle_system_msg(Request, From, Parent, ?MODULE, [],
 				{loop, State});
+		%% @todo HTTP/2 requires more timeouts than just the keepalive timeout.
+		%% We should have a timeout function in protocols that deal with
+		%% received timeouts. Currently the timeout messages are ignored.
 		{ws_upgrade, _, StreamRef, _, _} ->
 			Owner ! {gun_error, self(), StreamRef, {badstate,
 				"Websocket is only supported over HTTP/1.1."}},