XS_SURVEY_TIMEOUT socket option added.

It can be used to timeout the survey. Value is in milliseconds
and -1 means infinite (default).

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

6 files changed, 75 insertions, 5 deletions

diff --git a/src/options.cpp b/src/options.cpp
index 2a72add..f7bbdc4 100644
--- a/src/options.cpp
+++ b/src/options.cpp
@@ -50,6 +50,7 @@ xs::options_t::options_t () :
     keepalive (0),
     protocol (0),
     filter (XS_FILTER_PREFIX),
+    survey_timeout (-1),
     delay_on_close (true),
     delay_on_disconnect (true),
     send_identity (false),
@@ -258,6 +259,18 @@ int xs::options_t::setsockopt (int option_, const void *optval_,
         filter = *((int*) optval_);
         return 0;
 
+    case XS_SURVEY_TIMEOUT:
+        if (type != XS_SURVEYOR) {
+            errno = ENOTSUP;
+            return -1;
+        }
+        if (optvallen_ != sizeof (int)) {
+            errno = EINVAL;
+            return -1;
+        }
+        survey_timeout = *((int*) optval_);
+        return 0;
+
     }
 
     errno = EINVAL;
@@ -457,6 +470,19 @@ int xs::options_t::getsockopt (int option_, void *optval_, size_t *optvallen_)
         *optvallen_ = sizeof (int);
         return 0;
 
+    case XS_SURVEY_TIMEOUT:
+        if (type != XS_SURVEYOR) {
+            errno = ENOTSUP;
+            return -1;
+        }
+        if (*optvallen_ < sizeof (int)) {
+            errno = EINVAL;
+            return -1;
+        }
+        *((int*) optval_) = survey_timeout;
+        *optvallen_ = sizeof (int);
+        return 0;
+
     }
 
     errno = EINVAL;
diff --git a/src/options.hpp b/src/options.hpp
index fac6084..805f793 100644
--- a/src/options.hpp
+++ b/src/options.hpp
@@ -98,6 +98,9 @@ namespace xs
         //  Filter ID to be used with subscriptions and unsubscriptions.
         int filter;
 
+        //  Timeout for the survey in milliseconds. -1 means infinite.
+        int survey_timeout;
+
         //  If true, session reads all the pending messages from the pipe and
         //  sends them to the network when socket is closed.
         bool delay_on_close;
diff --git a/src/socket_base.cpp b/src/socket_base.cpp
index df182f1..1f45fd6 100644
--- a/src/socket_base.cpp
+++ b/src/socket_base.cpp
@@ -552,13 +552,13 @@ int xs::socket_base_t::send (msg_t *msg_, int flags_)
 
     //  In case of non-blocking send we'll simply propagate
     //  the error - including EAGAIN - up the stack.
-    if (flags_ & XS_DONTWAIT || options.sndtimeo == 0)
+    int timeout = sndtimeo ();
+    if (flags_ & XS_DONTWAIT || timeout == 0)
         return -1;
 
     //  Compute the time when the timeout should occur.
     //  If the timeout is infite, don't care. 
     clock_t clock ;
-    int timeout = options.sndtimeo;
     uint64_t end = timeout < 0 ? 0 : (clock.now_ms () + timeout);
 
     //  Oops, we couldn't send the message. Wait for the next
@@ -627,7 +627,8 @@ int xs::socket_base_t::recv (msg_t *msg_, int flags_)
     //  For non-blocking recv, commands are processed in case there's an
     //  activate_reader command already waiting int a command pipe.
     //  If it's not, return EAGAIN.
-    if (flags_ & XS_DONTWAIT || options.rcvtimeo == 0) {
+    int timeout = rcvtimeo ();
+    if (flags_ & XS_DONTWAIT || timeout == 0) {
         if (unlikely (process_commands (0, false) != 0))
             return -1;
         ticks = 0;
@@ -643,7 +644,6 @@ int xs::socket_base_t::recv (msg_t *msg_, int flags_)
     //  Compute the time when the timeout should occur.
     //  If the timeout is infite, don't care. 
     clock_t clock ;
-    int timeout = options.rcvtimeo;
     uint64_t end = timeout < 0 ? 0 : (clock.now_ms () + timeout);
 
     //  In blocking scenario, commands are processed over and over again until
@@ -926,3 +926,13 @@ void xs::socket_base_t::extract_flags (msg_t *msg_)
     rcvmore = msg_->flags () & msg_t::more ? true : false;
 }
 
+int xs::socket_base_t::rcvtimeo ()
+{
+    return options.rcvtimeo;
+}
+
+int xs::socket_base_t::sndtimeo ()
+{
+    return options.sndtimeo;
+}
+
diff --git a/src/socket_base.hpp b/src/socket_base.hpp
index 740fdde..9225ce7 100644
--- a/src/socket_base.hpp
+++ b/src/socket_base.hpp
@@ -119,6 +119,10 @@ namespace xs
         virtual bool xhas_in ();
         virtual int xrecv (xs::msg_t *msg_, int flags_);
 
+        //  Allow derived classes to modify timeouts.
+        virtual int rcvtimeo ();
+        virtual int sndtimeo ();
+
         //  i_pipe_events will be forwarded to these functions.
         virtual void xread_activated (pipe_t *pipe_);
         virtual void xwrite_activated (pipe_t *pipe_);
diff --git a/src/surveyor.cpp b/src/surveyor.cpp
index c5216bd..b76128b 100644
--- a/src/surveyor.cpp
+++ b/src/surveyor.cpp
@@ -18,6 +18,8 @@
     along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
+#include <algorithm>
+
 #include "surveyor.hpp"
 #include "err.hpp"
 #include "msg.hpp"
@@ -28,7 +30,8 @@
 xs::surveyor_t::surveyor_t (class ctx_t *parent_, uint32_t tid_, int sid_) :
     xsurveyor_t (parent_, tid_, sid_),
     receiving_responses (false),
-    survey_id (generate_random ())
+    survey_id (generate_random ()),
+    timeout (0)
 {
     options.type = XS_SURVEYOR;
 }
@@ -68,6 +71,12 @@ int xs::surveyor_t::xsend (msg_t *msg_, int flags_)
     //  Start waiting for responses from the peers.
     receiving_responses = true;
 
+    //  Set up the timeout for the survey (-1 means infinite).
+    if (!options.survey_timeout)
+        timeout = -1;
+    else
+        timeout = clock.now_ms () + options.survey_timeout;
+
     return 0;
 }
 
@@ -121,6 +130,16 @@ bool xs::surveyor_t::xhas_out ()
     return xsurveyor_t::xhas_out ();
 }
 
+int xs::surveyor_t::rcvtimeo ()
+{
+    int t = timeout - clock.now_ms ();
+    if (t < 0)
+        return options.rcvtimeo;
+    if (options.rcvtimeo < 0)
+        return t;
+    return std::min (t, options.rcvtimeo); 
+}
+
 xs::surveyor_session_t::surveyor_session_t (io_thread_t *io_thread_,
       bool connect_, socket_base_t *socket_, const options_t &options_,
       const char *protocol_, const char *address_) :
diff --git a/src/surveyor.hpp b/src/surveyor.hpp
index 83fdbb0..a77af49 100644
--- a/src/surveyor.hpp
+++ b/src/surveyor.hpp
@@ -23,6 +23,7 @@
 
 #include "xsurveyor.hpp"
 #include "stdint.hpp"
+#include "clock.hpp"
 
 namespace xs
 {
@@ -44,6 +45,7 @@ namespace xs
         int xrecv (xs::msg_t *msg_, int flags_);
         bool xhas_in ();
         bool xhas_out ();
+        int rcvtimeo ();
 
     private:
 
@@ -53,6 +55,12 @@ namespace xs
         //  The ID of the ongoing survey.
         uint32_t survey_id;
 
+        //  The time instant when the current survey expires.
+        uint64_t timeout;
+
+        //  Provides a way to measure time quickly.
+        clock_t clock;
+
         surveyor_t (const surveyor_t&);
         const surveyor_t &operator = (const surveyor_t&);
     };