XS_PLUGIN and XS_FILTER implementation

This patch introduces following features:
- XS_PLUGIN context option to add plugins to libxs
- XS_FILTER option to switch between different filter types
- Automatic loading of plug-ins is *not* implemented.

From the implementation point of view:
- standard prefix filter is implemented as a pluggable filter
- trie_t and mtrie_t are joined into a single class
- the code for 0MQ/3.1 compatibility is left in in the form of comments
- new test for testing re-subscriptions is added
Signed-off-by: Martin Sustrik <sustrik@250bpm.com>

1 files changed, 20 insertions, 9 deletions

diff --git a/src/xsub.hpp b/src/xsub.hpp
index 07fe026..4621570 100644
--- a/src/xsub.hpp
+++ b/src/xsub.hpp
@@ -21,11 +21,15 @@
 #ifndef __XS_XSUB_HPP_INCLUDED__
 #define __XS_XSUB_HPP_INCLUDED__
 
+#include <vector>
+
+#include "../include/xs.h"
+
 #include "socket_base.hpp"
 #include "session_base.hpp"
 #include "dist.hpp"
+#include "core.hpp"
 #include "fq.hpp"
-#include "trie.hpp"
 
 namespace xs
 {
@@ -34,8 +38,7 @@ namespace xs
     class pipe_t;
     class io_thread_t;
 
-    class xsub_t :
-        public socket_base_t
+    class xsub_t : public socket_base_t, public core_t
     {
     public:
 
@@ -57,14 +60,12 @@ namespace xs
 
     private:
 
+        //  Overloads from core_t class.
+        int filter_subscribed (const unsigned char *data_, size_t size_);
+
         //  Check whether the message matches at least one subscription.
         bool match (xs::msg_t *msg_);
 
-        //  Function to be applied to the trie to send all the subsciptions
-        //  upstream.
-        static void send_subscription (unsigned char *data_, size_t size_,
-            void *arg_);
-
         //  Fair queueing object for inbound pipes.
         fq_t fq;
 
@@ -72,7 +73,13 @@ namespace xs
         dist_t dist;
 
         //  The repository of subscriptions.
-        trie_t subscriptions;
+        struct filter_t
+        {
+            xs_filter_t *type;
+            void *instance;
+        };
+        typedef std::vector <filter_t> filters_t;
+        filters_t filters;
 
         //  If true, 'message' contains a matching message to return on the
         //  next recv call.
@@ -83,6 +90,10 @@ namespace xs
         //  there are following parts still waiting.
         bool more;
 
+        //  Different values stored while filter extensions are being executed.
+        pipe_t *tmp_pipe;
+        int tmp_filter_id;
+
         xsub_t (const xsub_t&);
         const xsub_t &operator = (const xsub_t&);
     };