Problem: duplicated code in socket-related functions

Solution: extract as_socket_base_t function

src/zmq.cpp

@@ -247,6 +247,16 @@ int zmq_ctx_destroy (void *ctx_)
 
 // Sockets
 
+static zmq::socket_base_t *as_socket_base_t (void *s_)
+{
+    zmq::socket_base_t *s = static_cast<zmq::socket_base_t *> (s_);
+    if (!s_ || !s->check_tag ()) {
+        errno = ENOTSOCK;
+        return NULL;
+    }
+    return s;
+}
+
 void *zmq_socket (void *ctx_, int type_)
 {
     if (!ctx_ || !((zmq::ctx_t *) ctx_)->check_tag ()) {
@@ -260,109 +270,83 @@ void *zmq_socket (void *ctx_, int type_)
 
 int zmq_close (void *s_)
 {
-    if (!s_ || !((zmq::socket_base_t*) s_)->check_tag ()) {
-        errno = ENOTSOCK;
+    zmq::socket_base_t *s = as_socket_base_t (s_);
+    if (!s)
         return -1;
-    }
-    ((zmq::socket_base_t*) s_)->close ();
+    s->close ();
     return 0;
 }
 
 int zmq_setsockopt (void *s_, int option_, const void *optval_,
     size_t optvallen_)
 {
-    if (!s_ || !((zmq::socket_base_t*) s_)->check_tag ()) {
-        errno = ENOTSOCK;
+    zmq::socket_base_t *s = as_socket_base_t (s_);
+    if (!s)
         return -1;
-    }
-    zmq::socket_base_t *s = (zmq::socket_base_t *) s_;
-    int result = s->setsockopt (option_, optval_, optvallen_);
-    return result;
+    return s->setsockopt (option_, optval_, optvallen_);
 }
 
 int zmq_getsockopt (void *s_, int option_, void *optval_, size_t *optvallen_)
 {
-    if (!s_ || !((zmq::socket_base_t*) s_)->check_tag ()) {
-        errno = ENOTSOCK;
+    zmq::socket_base_t *s = as_socket_base_t (s_);
+    if (!s)
         return -1;
-    }
-    zmq::socket_base_t *s = (zmq::socket_base_t *) s_;
-    int result = s->getsockopt (option_, optval_, optvallen_);
-    return result;
+    return s->getsockopt (option_, optval_, optvallen_);
 }
 
 int zmq_socket_monitor (void *s_, const char *addr_, int events_)
 {
-    if (!s_ || !((zmq::socket_base_t*) s_)->check_tag ()) {
-        errno = ENOTSOCK;
+    zmq::socket_base_t *s = as_socket_base_t (s_);
+    if (!s)
         return -1;
-    }
-    zmq::socket_base_t *s = (zmq::socket_base_t *) s_;
-    int result = s->monitor (addr_, events_);
-    return result;
+    return s->monitor (addr_, events_);
 }
 
 int zmq_join (void *s_, const char* group_)
 {
-    if (!s_ || !((zmq::socket_base_t*) s_)->check_tag ()) {
-        errno = ENOTSOCK;
+    zmq::socket_base_t *s = as_socket_base_t (s_);
+    if (!s)
         return -1;
-    }
-    zmq::socket_base_t *s = (zmq::socket_base_t *) s_;
-    int result = s->join (group_);
-    return result;
+    return s->join (group_);
 }
 
 int zmq_leave (void *s_, const char* group_)
 {
-    if (!s_ || !((zmq::socket_base_t*) s_)->check_tag ()) {
-        errno = ENOTSOCK;
+    zmq::socket_base_t *s = as_socket_base_t (s_);
+    if (!s)
         return -1;
-    }
-    zmq::socket_base_t *s = (zmq::socket_base_t *) s_;
-    int result = s->leave (group_);
-    return result;
+    return s->leave (group_);
 }
 
 int zmq_bind (void *s_, const char *addr_)
 {
-    if (!s_ || !((zmq::socket_base_t*) s_)->check_tag ()) {
-        errno = ENOTSOCK;
+    zmq::socket_base_t *s = as_socket_base_t (s_);
+    if (!s)
         return -1;
-    }
-    zmq::socket_base_t *s = (zmq::socket_base_t *) s_;
-    int result = s->bind (addr_);
-    return result;
+    return s->bind (addr_);
 }
 
 int zmq_connect (void *s_, const char *addr_)
 {
-    if (!s_ || !((zmq::socket_base_t*) s_)->check_tag ()) {
-        errno = ENOTSOCK;
+    zmq::socket_base_t *s = as_socket_base_t (s_);
+    if (!s)
         return -1;
-    }
-    zmq::socket_base_t *s = (zmq::socket_base_t *) s_;
-    int result = s->connect (addr_);
-    return result;
+    return s->connect (addr_);
 }
 
 int zmq_unbind (void *s_, const char *addr_)
 {
-    if (!s_ || !((zmq::socket_base_t*) s_)->check_tag ()) {
-        errno = ENOTSOCK;
+    zmq::socket_base_t *s = as_socket_base_t (s_);
+    if (!s)
         return -1;
-    }
-    zmq::socket_base_t *s = (zmq::socket_base_t *) s_;
     return s->term_endpoint (addr_);
 }
 
 int zmq_disconnect (void *s_, const char *addr_)
 {
-    if (!s_ || !((zmq::socket_base_t*) s_)->check_tag ()) {
-        errno = ENOTSOCK;
+    zmq::socket_base_t *s = as_socket_base_t (s_);
+    if (!s)
         return -1;
-    }
-    zmq::socket_base_t *s = (zmq::socket_base_t *) s_;
     return s->term_endpoint (addr_);
 }
 
@@ -392,10 +376,9 @@ int zmq_sendmsg (void *s_, zmq_msg_t *msg_, int flags_)
 
 int zmq_send (void *s_, const void *buf_, size_t len_, int flags_)
 {
-    if (!s_ || !((zmq::socket_base_t*) s_)->check_tag ()) {
-        errno = ENOTSOCK;
+    zmq::socket_base_t *s = as_socket_base_t (s_);
+    if (!s)
         return -1;
-    }
     zmq_msg_t msg;
     if (zmq_msg_init_size (&msg, len_))
         return -1;
@@ -405,7 +388,6 @@ int zmq_send (void *s_, const void *buf_, size_t len_, int flags_)
         assert (buf_);
         memcpy (zmq_msg_data (&msg), buf_, len_);
     }
-    zmq::socket_base_t *s = (zmq::socket_base_t *) s_;
     int rc = s_sendmsg (s, &msg, flags_);
     if (unlikely (rc < 0)) {
         int err = errno;
@@ -421,16 +403,14 @@ int zmq_send (void *s_, const void *buf_, size_t len_, int flags_)
 
 int zmq_send_const (void *s_, const void *buf_, size_t len_, int flags_)
 {
-    if (!s_ || !((zmq::socket_base_t*) s_)->check_tag ()) {
-        errno = ENOTSOCK;
+    zmq::socket_base_t *s = as_socket_base_t (s_);
+    if (!s)
         return -1;
-    }
     zmq_msg_t msg;
     int rc = zmq_msg_init_data (&msg, (void *)buf_, len_, NULL, NULL);
     if (rc != 0)
         return -1;
 
-    zmq::socket_base_t *s = (zmq::socket_base_t *) s_;
     rc = s_sendmsg (s, &msg, flags_);
     if (unlikely (rc < 0)) {
         int err = errno;
@@ -454,10 +434,9 @@ int zmq_send_const (void *s_, const void *buf_, size_t len_, int flags_)
 //
 int zmq_sendiov (void *s_, iovec *a_, size_t count_, int flags_)
 {
-    if (!s_ || !((zmq::socket_base_t*) s_)->check_tag ()) {
-        errno = ENOTSOCK;
+    zmq::socket_base_t *s = as_socket_base_t (s_);
+    if (!s)
         return -1;
-    }
     if (unlikely (count_ <= 0 || !a_)) {
         errno = EINVAL;
         return -1;
@@ -465,7 +444,6 @@ int zmq_sendiov (void *s_, iovec *a_, size_t count_, int flags_)
 
     int rc = 0;
     zmq_msg_t msg;
-    zmq::socket_base_t *s = (zmq::socket_base_t *) s_;
 
     for (size_t i = 0; i < count_; ++i) {
         rc = zmq_msg_init_size (&msg, a_[i].iov_len);
@@ -512,15 +490,13 @@ int zmq_recvmsg (void *s_, zmq_msg_t *msg_, int flags_)
 
 int zmq_recv (void *s_, void *buf_, size_t len_, int flags_)
 {
-    if (!s_ || !((zmq::socket_base_t*) s_)->check_tag ()) {
-        errno = ENOTSOCK;
+    zmq::socket_base_t *s = as_socket_base_t (s_);
+    if (!s)
         return -1;
-    }
     zmq_msg_t msg;
     int rc = zmq_msg_init (&msg);
     errno_assert (rc == 0);
 
-    zmq::socket_base_t *s = (zmq::socket_base_t *) s_;
     int nbytes = s_recvmsg (s, &msg, flags_);
     if (unlikely (nbytes < 0)) {
         int err = errno;
@@ -562,17 +538,14 @@ int zmq_recv (void *s_, void *buf_, size_t len_, int flags_)
 //
 int zmq_recviov (void *s_, iovec *a_, size_t *count_, int flags_)
 {
-    if (!s_ || !((zmq::socket_base_t*) s_)->check_tag ()) {
-        errno = ENOTSOCK;
+    zmq::socket_base_t *s = as_socket_base_t (s_);
+    if (!s)
         return -1;
-    }
     if (unlikely (!count_ || *count_ <= 0 || !a_)) {
         errno = EINVAL;
         return -1;
     }
 
-    zmq::socket_base_t *s = (zmq::socket_base_t *) s_;
-
     size_t count = *count_;
     int nread = 0;
     bool recvmore = true;
@@ -634,24 +607,18 @@ int zmq_msg_init_data (zmq_msg_t *msg_, void *data_, size_t size_,
 
 int zmq_msg_send (zmq_msg_t *msg_, void *s_, int flags_)
 {
-    if (!s_ || !((zmq::socket_base_t*) s_)->check_tag ()) {
-        errno = ENOTSOCK;
+    zmq::socket_base_t *s = as_socket_base_t (s_);
+    if (!s)
         return -1;
-    }
-    zmq::socket_base_t *s = (zmq::socket_base_t *) s_;
-    int result = s_sendmsg (s, msg_, flags_);
-    return result;
+    return s_sendmsg (s, msg_, flags_);
 }
 
 int zmq_msg_recv (zmq_msg_t *msg_, void *s_, int flags_)
 {
-    if (!s_ || !((zmq::socket_base_t*) s_)->check_tag ()) {
-        errno = ENOTSOCK;
+    zmq::socket_base_t *s = as_socket_base_t (s_);
+    if (!s)
         return -1;
-    }
-    zmq::socket_base_t *s = (zmq::socket_base_t *) s_;
-    int result = s_recvmsg (s, msg_, flags_);
-    return result;
+    return s_recvmsg (s, msg_, flags_);
 }
 
 int zmq_msg_close (zmq_msg_t *msg_)