Filters can transform user subscriptions to wire subscription

Till now the subscription, as specified by the user, was send
upstream.

This patch allows SUB-side filter to transform the user subscription
into wire subscription. For example, only a has can be sent upstream
instead of a perfect subscription.

Signed-off-by: Martin Sustrik <sustrik@250bpm.com>

1 files changed, 8 insertions, 4 deletions

diff --git a/src/sub.hpp b/src/sub.hpp
index 4c3bf7f..c50c0bd 100644
--- a/src/sub.hpp
+++ b/src/sub.hpp
@@ -27,6 +27,7 @@
 #include "../include/xs.h"
 
 #include "xsub.hpp"
+#include "core.hpp"
 
 namespace xs
 {
@@ -36,21 +37,26 @@ namespace xs
     class io_thread_t;
     class socket_base_t;
 
-    class sub_t : public xsub_t
+    class sub_t : public xsub_t, public core_t
     {
     public:
 
         sub_t (xs::ctx_t *parent_, uint32_t tid_, int sid_);
         ~sub_t ();
 
-    protected:
+    private:
 
+        //  Overloaded functions from socket_base_t.
         int xsetsockopt (int option_, const void *optval_, size_t optvallen_);
         int xsend (xs::msg_t *msg_, int flags_);
         int xrecv (xs::msg_t *msg_, int flags_);
         bool xhas_in ();
         bool xhas_out ();
 
+        //  Overloaded functions from core_t.
+        int filter_subscribed (const unsigned char *data_, size_t size_);
+        int filter_unsubscribed (const unsigned char *data_, size_t size_);
+
         //  The repository of subscriptions.
         struct filter_t
         {
@@ -69,8 +75,6 @@ namespace xs
         bool has_message;
         msg_t message;
 
-    private:
-
         //  Check whether the message matches at least one subscription.
         bool match (xs::msg_t *msg_);