Add sockopt ZMQ_RCVTIMEO/ZMQ_SNDTIMEO.

- Add doc and tests
- Add options and setup
- Wait using poll/select

Signed-off-by: Fabien Ninoles <fabien@tzone.org>
Signed-off-by: Martin Sustrik <sustrik@250bpm.com>

1 files changed, 67 insertions, 33 deletions

diff --git a/src/socket_base.cpp b/src/socket_base.cpp
index 2b1d8af..dc6b5f5 100644
--- a/src/socket_base.cpp
+++ b/src/socket_base.cpp
@@ -288,7 +288,7 @@ int zmq::socket_base_t::getsockopt (int option_, void *optval_,
             errno = EINVAL;
             return -1;
         }
-        int rc = process_commands (false, false);
+        int rc = process_commands (0, false);
         if (rc != 0 && (errno == EINTR || errno == ETERM))
             return -1;
         errno_assert (rc == 0);
@@ -475,7 +475,7 @@ int zmq::socket_base_t::send (msg_t *msg_, int flags_)
     }
 
     //  Process pending commands, if any.
-    int rc = process_commands (false, true);
+    int rc = process_commands (0, true);
     if (unlikely (rc != 0))
         return -1;
 
@@ -487,20 +487,38 @@ int zmq::socket_base_t::send (msg_t *msg_, int flags_)
     rc = xsend (msg_, flags_);
     if (rc == 0)
         return 0;
+    if (unlikely (errno != EAGAIN))
+        return -1;
 
     //  In case of non-blocking send we'll simply propagate
-    //  the error - including EAGAIN - upwards.
-    if (flags_ & ZMQ_DONTWAIT)
+    //  the error - including EAGAIN - up the stack.
+    if (flags_ & ZMQ_DONTWAIT || options.sndtimeo == 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
     //  command, process it and try to send the message again.
-    while (rc != 0) {
-        if (errno != EAGAIN)
-            return -1;
-        if (unlikely (process_commands (true, false) != 0))
+    //  If timeout is reached in the meantime, return EAGAIN.
+    while (true) {
+        if (unlikely (process_commands (timeout, false) != 0))
             return -1;
         rc = xsend (msg_, flags_);
+        if (rc == 0)
+            break;
+        if (unlikely (errno != EAGAIN))
+            return -1;
+        if (timeout > 0) {
+            timeout = end - clock.now_ms ();
+            if (timeout <= 0) {
+                errno = EAGAIN;
+                return -1;
+            }
+        }
     }
     return 0;
 }
@@ -521,7 +539,8 @@ int zmq::socket_base_t::recv (msg_t *msg_, int flags_)
 
     //  Get the message.
     int rc = xrecv (msg_, flags_);
-    int err = errno;
+    if (unlikely (rc != 0 && errno != EAGAIN))
+        return -1;
 
     //  Once every inbound_poll_rate messages check for signals and process
     //  incoming commands. This happens only if we are not polling altogether
@@ -532,7 +551,7 @@ int zmq::socket_base_t::recv (msg_t *msg_, int flags_)
     //  described above) from the one used by 'send'. This is because counting
     //  ticks is more efficient than doing RDTSC all the time.
     if (++ticks == inbound_poll_rate) {
-        if (unlikely (process_commands (false, false) != 0))
+        if (unlikely (process_commands (0, false) != 0))
             return -1;
         ticks = 0;
     }
@@ -545,17 +564,12 @@ int zmq::socket_base_t::recv (msg_t *msg_, int flags_)
         return 0;
     }
 
-    //  If we don't have the message, restore the original cause of the problem.
-    errno = err;
-
     //  If the message cannot be fetched immediately, there are two scenarios.
     //  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_ & ZMQ_DONTWAIT) {
-        if (errno != EAGAIN)
-            return -1;
-        if (unlikely (process_commands (false, false) != 0))
+    if (flags_ & ZMQ_DONTWAIT || options.rcvtimeo == 0) {
+        if (unlikely (process_commands (0, false) != 0))
             return -1;
         ticks = 0;
 
@@ -568,17 +582,33 @@ int zmq::socket_base_t::recv (msg_t *msg_, int flags_)
         return rc;
     }
 
+    //  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
     //  we are able to fetch a message.
     bool block = (ticks != 0);
-    while (rc != 0) {
-        if (errno != EAGAIN)
-            return -1;
-        if (unlikely (process_commands (block, false) != 0))
+    while (true) {
+        if (unlikely (process_commands (block ? timeout : 0, false) != 0))
             return -1;
         rc = xrecv (msg_, flags_);
-        ticks = 0;
+        if (rc == 0) {
+            ticks = 0;
+            break;
+        }
+        if (unlikely (errno != EAGAIN))
+            return -1;
         block = true;
+        if (timeout > 0) {
+            timeout = end - clock.now_ms ();
+            if (timeout <= 0) {
+                errno = EAGAIN;
+                return -1;
+            }
+        }
     }
 
     rcvmore = msg_->flags () & msg_t::more;
@@ -658,18 +688,20 @@ void zmq::socket_base_t::start_reaping (poller_t *poller_)
     check_destroy ();
 }
 
-int zmq::socket_base_t::process_commands (bool block_, bool throttle_)
+int zmq::socket_base_t::process_commands (int timeout_, bool throttle_)
 {
     int rc;
     command_t cmd;
-    if (block_) {
-        rc = mailbox.recv (&cmd, true);
-        if (rc == -1 && errno == EINTR)
-            return -1;
-        errno_assert (rc == 0);
+    if (timeout_ != 0) {
+
+        //  If we are asked to wait, simply ask mailbox to wait.
+        rc = mailbox.recv (&cmd, timeout_);
     }
     else {
 
+        //  If we are asked not to wait, check whether we haven't processed
+        //  commands recently, so that we can throttle the new commands.
+
         //  Get the CPU's tick counter. If 0, the counter is not available.
         uint64_t tsc = zmq::clock_t::rdtsc ();
 
@@ -690,7 +722,7 @@ int zmq::socket_base_t::process_commands (bool block_, bool throttle_)
         }
 
         //  Check whether there are any commands pending for this thread.
-        rc = mailbox.recv (&cmd, false);
+        rc = mailbox.recv (&cmd, 0);
     }
 
     //  Process all the commands available at the moment.
@@ -701,7 +733,7 @@ int zmq::socket_base_t::process_commands (bool block_, bool throttle_)
             return -1;
         errno_assert (rc == 0);
         cmd.destination->process_command (cmd);
-        rc = mailbox.recv (&cmd, false);
+        rc = mailbox.recv (&cmd, 0);
      }
 
     if (ctx_terminated) {
@@ -797,9 +829,11 @@ void zmq::socket_base_t::xhiccuped (pipe_t *pipe_)
 
 void zmq::socket_base_t::in_event ()
 {
-    //  Process any commands from other threads/sockets that may be available
-    //  at the moment. Ultimately, socket will be destroyed.
-    process_commands (false, false);
+    //  This function is invoked only once the socket is running in the context
+    //  of the reaper thread. Process any commands from other threads/sockets
+    //  that may be available at the moment. Ultimately, the socket will
+    //  be destroyed.
+    process_commands (0, false);
     check_destroy ();
 }