From 72161fb075025410312c6735d681c3de9a36a4e5 Mon Sep 17 00:00:00 2001
From: Martin Sustrik <sustrik@fastmq.commkdir>
Date: Mon, 28 Dec 2009 21:29:31 +0100
Subject: format of subscriptions changed (no * needed anymore)

---
 src/sub.cpp | 90 +++++++++++++++++++++++++------------------------------------
 1 file changed, 37 insertions(+), 53 deletions(-)

(limited to 'src/sub.cpp')

diff --git a/src/sub.cpp b/src/sub.cpp
index e5dbe76..95039d7 100644
--- a/src/sub.cpp
+++ b/src/sub.cpp
@@ -17,6 +17,8 @@
     along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
+#include <string.h>
+
 #include "../bindings/c/zmq.h"
 
 #include "sub.hpp"
@@ -67,41 +69,30 @@ int zmq::sub_t::xsetsockopt (int option_, const void *optval_,
     size_t optvallen_)
 {
     if (option_ == ZMQ_SUBSCRIBE) {
-        std::string subscription ((const char*) optval_, optvallen_);
-        if (subscription == "*")
+        if (!optvallen_)
             all_count++;
-        else if (subscription [subscription.size () - 1] == '*')
-            prefixes.insert (subscription.substr (0, subscription.size () - 1));
-        else
-            topics.insert (subscription);
+        else 
+            subscriptions.insert (std::string ((const char*) optval_,
+                optvallen_));
         return 0;
     }
     
     if (option_ == ZMQ_UNSUBSCRIBE) {
-        std::string subscription ((const char*) optval_, optvallen_);
-        if (subscription == "*") {
+        if (!optvallen_) {
             if (!all_count) {
                 errno = EINVAL;
                 return -1;
             }
             all_count--;
         }
-        else if (subscription [subscription.size () - 1] == '*') {
-            subscriptions_t::iterator it = prefixes.find (
-                subscription.substr (0, subscription.size () - 1));
-            if (it == prefixes.end ()) {
-                errno = EINVAL;
-                return -1;
-            }
-            prefixes.erase (it);
-        }
         else {
-            subscriptions_t::iterator it = topics.find (subscription);
-            if (it == topics.end ()) {
+            subscriptions_t::iterator it = subscriptions.find (
+                std::string ((const char*) optval_, optvallen_));
+            if (it == subscriptions.end ()) {
                 errno = EINVAL;
                 return -1;
             }
-            topics.erase (it);
+            subscriptions.erase (it);
         }
         return 0;
     }
@@ -124,44 +115,37 @@ int zmq::sub_t::xflush ()
 
 int zmq::sub_t::xrecv (zmq_msg_t *msg_, int flags_)
 {
-    while (true) {
-
-        //  Get a message using fair queueing algorithm.
-        int rc = fq.recv (msg_, flags_);
+    //  Get a message using fair queueing algorithm.
+    int rc = fq.recv (msg_, flags_);
 
-        //  If there's no message available, return immediately.
-        if (rc != 0 && errno == EAGAIN)
-            return -1;
+    //  If there's no message available, return immediately.
+    if (rc != 0 && errno == EAGAIN)
+        return -1;
 
-        //  If there is no subscription return -1/EAGAIN.
-        if (!all_count && prefixes.empty () && topics.empty ()) {
-            errno = EAGAIN;
-            return -1; 
-        }
-
-        //  If there is at least one "*" subscription, the message matches.
-        if (all_count)
-            return 0;
+    //  If there is at least one * subscription, the message matches.
+    if (all_count)
+        return 0;
 
-        //  Check the message format.
-        //  TODO: We should either ignore the message or drop the connection
-        //  if the message doesn't conform with the expected format.
-        unsigned char *data = (unsigned char*) zmq_msg_data (msg_);
-        zmq_assert (*data <= zmq_msg_size (msg_) - 1);
-        std::string topic ((const char*) (data + 1), *data);
-
-        //  Check whether the message matches at least one prefix subscription.
-        for (subscriptions_t::iterator it = prefixes.begin ();
-              it != prefixes.end (); it++)
-            if (it->size () <= topic.size () &&
-                  *it == topic.substr (0, it->size ()))
-                return 0;
-
-        //  Check whether the message matches an exact match subscription.
-        subscriptions_t::iterator it = topics.find (topic);
-        if (it != topics.end ())
+    //  Check whether the message matches at least one prefix subscription.
+    //  TODO: Make this efficient - O(log(n)) where n is number of characters in
+    //  the longest subscription string.
+    for (subscriptions_t::iterator it = subscriptions.begin ();
+          it != subscriptions.end (); it++) {
+        size_t msg_size = zmq_msg_size (msg_);
+        size_t sub_size = it->size ();
+        if (sub_size <= msg_size &&
+              memcmp (zmq_msg_data (msg_), it->data (), sub_size) == 0)
             return 0;
     }
+
+    //  The message did not pass the filter. Trim it.
+    //  Note that we are returning a different error code so that the caller
+    //  knows there are more messages available. We cannot loop here as
+    //  a stream of non-matching messages would create a DoS situation.
+    zmq_msg_close (msg_);
+    zmq_msg_init (msg_);
+    errno = EINPROGRESS;
+    return -1;
 }
 
 bool zmq::sub_t::xhas_in ()
-- 
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