fixes #522 Separate out the endpoint plumbing

This separates the plumbing for endpoints into distinct
dialer and listeners.  Some of the transports could benefit
from further separation, but we've done some rather larger
separation e.g. for the websocket transport.

IPC would be a good one to update later, when we start looking
at exposing a more natural underlying API.

1 files changed, 75 insertions, 44 deletions

diff --git a/src/core/transport.h b/src/core/transport.h
index e45aa7ec..257d232d 100644
--- a/src/core/transport.h
+++ b/src/core/transport.h
@@ -11,30 +11,11 @@
 #ifndef CORE_TRANSPORT_H
 #define CORE_TRANSPORT_H
 
-// Transport implementation details.  Transports must implement the
-// interfaces in this file.
-struct nni_tran {
-	// tran_version is the version of the transport ops that this
-	// transport implements.  We only bother to version the main
-	// ops vector.
-	uint32_t tran_version;
-
-	// tran_scheme is the transport scheme, such as "tcp" or "inproc".
-	const char *tran_scheme;
-
-	// tran_ep links our endpoint-specific operations.
-	const nni_tran_ep_ops *tran_ep;
-
-	// tran_pipe links our pipe-specific operations.
-	const nni_tran_pipe_ops *tran_pipe;
-
-	// tran_init, if not NULL, is called once during library
-	// initialization.
-	int (*tran_init)(void);
-
-	// tran_fini, if not NULL, is called during library deinitialization.
-	// It should release any global resources, close any open files, etc.
-	void (*tran_fini)(void);
+// Endpoint modes.  Currently used by transports.  Remove this when we make
+// transport dialers and listeners explicit.
+enum nni_ep_mode {
+	NNI_EP_MODE_DIAL   = 1,
+	NNI_EP_MODE_LISTEN = 2,
 };
 
 // We quite intentionally use a signature where the upper word is nonzero,
@@ -48,7 +29,8 @@ struct nni_tran {
 #define NNI_TRANSPORT_V0 0x54520000
 #define NNI_TRANSPORT_V1 0x54520001
 #define NNI_TRANSPORT_V2 0x54520002
-#define NNI_TRANSPORT_VERSION NNI_TRANSPORT_V2
+#define NNI_TRANSPORT_V3 0x54520003
+#define NNI_TRANSPORT_VERSION NNI_TRANSPORT_V3
 
 // Option handlers.
 struct nni_tran_option {
@@ -81,40 +63,60 @@ struct nni_tran_option {
 // For a given endpoint, the framework holds a lock so that each entry
 // point is run exclusively of the others. (Transports must still guard
 // against any asynchronous operations they manage themselves, though.)
-struct nni_tran_ep_ops {
-	// ep_init creates a vanilla endpoint. The value created is
-	// used for the first argument for all other endpoint
-	// functions.
-	int (*ep_init)(void **, nni_url *, nni_sock *, int);
 
-	// ep_fini frees the resources associated with the endpoint.
-	// The endpoint will already have been closed.
-	void (*ep_fini)(void *);
+struct nni_tran_dialer_ops {
+	// d_init creates a vanilla dialer. The value created is
+	// used for the first argument for all other dialer functions.
+	int (*d_init)(void **, nni_url *, nni_sock *);
+
+	// d_fini frees the resources associated with the dialer.
+	// The dialer will already have been closed.
+	void (*d_fini)(void *);
 
-	// ep_connect establishes a connection.  It can return errors
+	// d_connect establishes a connection.  It can return errors
 	// NNG_EACCESS, NNG_ECONNREFUSED, NNG_EBADADDR,
 	// NNG_ECONNFAILED, NNG_ETIMEDOUT, and NNG_EPROTO.
-	void (*ep_connect)(void *, nni_aio *);
+	void (*d_connect)(void *, nni_aio *);
+
+	// d_close stops the dialer from operating altogether.  It
+	// does not affect pipes that have already been created.  It is
+	// nonblocking.
+	void (*d_close)(void *);
+
+	// d_options is an array of dialer options.  The final
+	// element must have a NULL name. If this member is NULL, then
+	// no dialer specific options are available.
+	nni_tran_option *d_options;
+};
+
+struct nni_tran_listener_ops {
+	// l_init creates a vanilla listener. The value created is
+	// used for the first argument for all other listener functions.
+	int (*l_init)(void **, nni_url *, nni_sock *);
 
-	// ep_bind just does the bind() and listen() work,
+	// l_fini frees the resources associated with the listener.
+	// The listener will already have been closed.
+	void (*l_fini)(void *);
+
+	// l_bind just does the bind() and listen() work,
 	// reserving the address but not creating any connections.
 	// It should return NNG_EADDRINUSE if the address is already
 	// taken.  It can also return NNG_EBADADDR for an unsuitable
 	// address, or NNG_EACCESS for permission problems.
-	int (*ep_bind)(void *);
+	int (*l_bind)(void *);
 
-	// ep_accept accepts an inbound connection.
-	void (*ep_accept)(void *, nni_aio *);
+	// l_accept accepts an inbound connection.
+	void (*l_accept)(void *, nni_aio *);
 
-	// ep_close stops the endpoint from operating altogether.  It
+	// l_close stops the listener from operating altogether.  It
 	// does not affect pipes that have already been created.  It is
 	// nonblocking.
-	void (*ep_close)(void *);
+	void (*l_close)(void *);
 
-	// ep_options is an array of endpoint options.  The final
+	// l_options is an array of listener options.  The final
 	// element must have a NULL name. If this member is NULL, then
-	// no transport specific options are available.
-	nni_tran_option *ep_options;
+	// no dialer specific options are available.
+	nni_tran_option *l_options;
 };
 
 // Pipe operations are entry points called by the socket. These may be
@@ -168,6 +170,35 @@ struct nni_tran_pipe_ops {
 	nni_tran_option *p_options;
 };
 
+// Transport implementation details.  Transports must implement the
+// interfaces in this file.
+struct nni_tran {
+	// tran_version is the version of the transport ops that this
+	// transport implements.  We only bother to version the main
+	// ops vector.
+	uint32_t tran_version;
+
+	// tran_scheme is the transport scheme, such as "tcp" or "inproc".
+	const char *tran_scheme;
+
+	// tran_dialer links our dialer-specific operations.
+	const nni_tran_dialer_ops *tran_dialer;
+
+	// tran_listener links our listener-specific operations.
+	const nni_tran_listener_ops *tran_listener;
+
+	// tran_pipe links our pipe-specific operations.
+	const nni_tran_pipe_ops *tran_pipe;
+
+	// tran_init, if not NULL, is called once during library
+	// initialization.
+	int (*tran_init)(void);
+
+	// tran_fini, if not NULL, is called during library deinitialization.
+	// It should release any global resources, close any open files, etc.
+	void (*tran_fini)(void);
+};
+
 // These APIs are used by the framework internally, and not for use by
 // transport implementations.
 extern nni_tran *nni_tran_find(nni_url *);