Expired survey returns ETIMEDOUT instead of EAGAIN

Up to now, when survey in surveyor pattern expired, xs_recv()
returned EAGAIN. That made it impossible to distinguish
epired survey from expired receive timeout (XS_RCVTIMEO).
This patch make errors different in both cases.

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

5 files changed, 16 insertions, 4 deletions

diff --git a/doc/xs_recv.txt b/doc/xs_recv.txt
index 5706432..484c317 100644
--- a/doc/xs_recv.txt
+++ b/doc/xs_recv.txt
@@ -65,6 +65,8 @@ The provided 'socket' was invalid.
 *EINTR*::
 The operation was interrupted by delivery of a signal before a message was
 available.
+*ETIMEDOUT*::
+Survey has timed out. (Applicable only to XS_SURVEYOR socket.)
 
 
 EXAMPLE
diff --git a/doc/xs_recvmsg.txt b/doc/xs_recvmsg.txt
index 4a88177..86a15a6 100644
--- a/doc/xs_recvmsg.txt
+++ b/doc/xs_recvmsg.txt
@@ -67,6 +67,8 @@ The operation was interrupted by delivery of a signal before a message was
 available.
 *EFAULT*::
 The message passed to the function was invalid.
+*ETIMEDOUT*::
+Survey has timed out. (Applicable only to XS_SURVEYOR socket.)
 
 
 EXAMPLE
diff --git a/src/err.cpp b/src/err.cpp
index e330ed2..a771030 100644
--- a/src/err.cpp
+++ b/src/err.cpp
@@ -157,7 +157,7 @@ const char *xs::wsa_error_no (int no_)
         (no_ == WSAETOOMANYREFS) ?
             "Too many references can't splice" : 
         (no_ == WSAETIMEDOUT) ?
-            "Connection timed out" : 
+            "Operation timed out" : 
         (no_ == WSAECONNREFUSED) ?
             "Connection refused" : 
         (no_ == WSAELOOP) ?
diff --git a/src/surveyor.cpp b/src/surveyor.cpp
index b72b91b..bd19b8a 100644
--- a/src/surveyor.cpp
+++ b/src/surveyor.cpp
@@ -92,8 +92,16 @@ int xs::surveyor_t::xrecv (msg_t *msg_, int flags_)
 
     //  Get the first part of the response -- the survey ID.
     rc = xsurveyor_t::xrecv (msg_, flags_);
-    if (rc != 0)
-        return rc;
+    if (rc != 0) {
+        if (errno != EAGAIN)
+            return -1;
+
+        //  In case of AGAIN we should check whether the survey timeout expired.
+        //  If so, we should return ETIMEDOUT so that user is able to
+        //  distinguish survey timeout from RCVTIMEO-caused timeout.
+        errno = now_ms () >= timeout ? ETIMEDOUT : EAGAIN;
+        return -1;
+    }
 
     //  Check whether this is response for the onging survey. If not, we can
     //  drop the response.
diff --git a/tests/survey.cpp b/tests/survey.cpp
index f21b217..2179779 100644
--- a/tests/survey.cpp
+++ b/tests/survey.cpp
@@ -126,7 +126,7 @@ int XS_TEST_MAIN ()
     assert (rc == 3);
     void *watch = xs_stopwatch_start ();
     rc = xs_recv (surveyor, buf, sizeof (buf), 0);
-    assert (rc == - 1 && errno == EAGAIN);
+    assert (rc == - 1 && errno == ETIMEDOUT);
     unsigned long elapsed = xs_stopwatch_stop (watch) / 1000;
     time_assert (elapsed, (unsigned long) timeout);