From f2ff2c6e5c4e244dea28e1ac6ec3f886b7ebc356 Mon Sep 17 00:00:00 2001
From: Martin Sustrik <sustrik@fastmq.commkdir>
Date: Wed, 30 Sep 2009 10:08:35 +0200
Subject: checking for available messages added to ypipe/pipe

---
 src/pipe.cpp  | 11 +++++++++++
 src/pipe.hpp  |  3 +++
 src/ypipe.hpp | 24 ++++++++++++++++--------
 3 files changed, 30 insertions(+), 8 deletions(-)

(limited to 'src')

diff --git a/src/pipe.cpp b/src/pipe.cpp
index f8dfcb8..e444520 100644
--- a/src/pipe.cpp
+++ b/src/pipe.cpp
@@ -36,6 +36,17 @@ zmq::reader_t::~reader_t ()
 {
 }
 
+bool zmq::reader_t::check_read ()
+{
+    //  Check if there's an item in the pipe.
+    if (pipe->check_read ())
+        return true;
+
+    //  If not, deactivate the pipe.
+    endpoint->kill (this);
+    return false;
+}
+
 bool zmq::reader_t::read (zmq_msg_t *msg_)
 {
     if (!pipe->read (msg_)) {
diff --git a/src/pipe.hpp b/src/pipe.hpp
index 699e3f7..ecbce7d 100644
--- a/src/pipe.hpp
+++ b/src/pipe.hpp
@@ -42,6 +42,9 @@ namespace zmq
 
         void set_endpoint (i_endpoint *endpoint_);
 
+        //  Returns true if there is at least one message to read in the pipe.
+        bool check_read ();
+
         //  Reads a message to the underlying pipe.
         bool read (zmq_msg_t *msg_);
 
diff --git a/src/ypipe.hpp b/src/ypipe.hpp
index 6c51b63..0a9b5d5 100644
--- a/src/ypipe.hpp
+++ b/src/ypipe.hpp
@@ -106,16 +106,12 @@ namespace zmq
             return true;
         }
 
-        //  Reads an item from the pipe. Returns false if there is no value.
-        //  available.
-        inline bool read (T *value_)
+        //  Check whether item is available for reading.
+        inline bool check_read ()
         {
-            //  Was the value prefetched already? If so, return it.
-            if (&queue.front () != r) {
-                 *value_ = queue.front ();
-                 queue.pop ();
+            //  Was the value prefetched already? If so, return.
+            if (&queue.front () != r)
                  return true;
-            }
 
             //  There's no prefetched value, so let us prefetch more values.
             //  (Note that D is a template parameter. Becaue of that one of
@@ -165,6 +161,18 @@ namespace zmq
                     return false;
             }
 
+            //  There was at least one value prefetched.
+            return true;
+        }
+
+        //  Reads an item from the pipe. Returns false if there is no value.
+        //  available.
+        inline bool read (T *value_)
+        {
+            //  Try to prefetch a value.
+            if (!check_read ())
+                return false;
+
             //  There was at least one value prefetched.
             //  Return it to the caller.
             *value_ = queue.front ();
-- 
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