[socket] Macro abuse for requestor queue func def

The requestor (acceptor, writer and reader) functions are
virtually identical, so to ensure quality and not having
to write the exact same functions three times, we make
use of some macro magic for their declaration.

OTP-15565

1 files changed, 127 insertions, 282 deletions

diff --git a/erts/emulator/nifs/common/socket_nif.c b/erts/emulator/nifs/common/socket_nif.c
index ba8e2137e8..3caffd8554 100644
--- a/erts/emulator/nifs/common/socket_nif.c
+++ b/erts/emulator/nifs/common/socket_nif.c
@@ -2243,15 +2243,16 @@ static void dec_socket(int domain, int type, int protocol);
                                  ERL_NIF_TERM      ref);        \
     static BOOLEAN_T O##_pop(ErlNifEnv*        env,             \
                              SocketDescriptor* descP,           \
-                             ErlNifPid*        pid,             \
-                             ESockMonitor*     mon,             \
-                             ERL_NIF_TERM*     ref);            \
+                             SocketRequestor*  reqP);           \
     static BOOLEAN_T O##_unqueue(ErlNifEnv*        env,         \
                                  SocketDescriptor* descP,       \
                                  const ErlNifPid*  pid);
 ESOCK_OPERATOR_FUNCS_DEFS
 #undef ESOCK_OPERATOR_FUNCS_DEF
 
+static BOOLEAN_T requestor_pop(SocketRequestQueue* q,
+                               SocketRequestor*    reqP);
+
 static BOOLEAN_T qsearch4pid(ErlNifEnv*          env,
                              SocketRequestQueue* q,
                              ErlNifPid*          pid);
@@ -5112,10 +5113,7 @@ ERL_NIF_TERM naccept_accepting_current_accept(ErlNifEnv*        env,
          *
          */
 
-        if (acceptor_pop(env, descP,
-                         &descP->currentAcceptor.pid,
-                         &descP->currentAcceptor.mon,
-                         &descP->currentAcceptor.ref)) {
+        if (acceptor_pop(env, descP, &descP->currentAcceptor)) {
 
             /* There was another one */
 
@@ -13164,10 +13162,7 @@ ERL_NIF_TERM ncancel_accept_current(ErlNifEnv*        env,
 
     SSDBG( descP, ("SOCKET", "ncancel_accept_current -> cancel res: %T\r\n", res) );
 
-    if (acceptor_pop(env, descP,
-                     &descP->currentAcceptor.pid,
-                     &descP->currentAcceptor.mon,
-                     &descP->currentAcceptor.ref)) {
+    if (acceptor_pop(env, descP, &descP->currentAcceptor)) {
         
         /* There was another one */
         
@@ -13288,10 +13283,7 @@ ERL_NIF_TERM ncancel_send_current(ErlNifEnv*        env,
 
     SSDBG( descP, ("SOCKET", "ncancel_send_current -> cancel res: %T\r\n", res) );
 
-    if (writer_pop(env, descP,
-                   &descP->currentWriter.pid,
-                   &descP->currentWriter.mon,
-                   &descP->currentWriter.ref)) {
+    if (writer_pop(env, descP, &descP->currentWriter)) {
         
         /* There was another one */
         
@@ -13410,10 +13402,7 @@ ERL_NIF_TERM ncancel_recv_current(ErlNifEnv*        env,
 
     SSDBG( descP, ("SOCKET", "ncancel_recv_current -> cancel res: %T\r\n", res) );
 
-    if (reader_pop(env, descP,
-                   &descP->currentReader.pid,
-                   &descP->currentReader.mon,
-                   &descP->currentReader.ref)) {
+    if (reader_pop(env, descP, &descP->currentReader)) {
         
         /* There was another one */
         
@@ -13619,10 +13608,7 @@ ERL_NIF_TERM send_check_result(ErlNifEnv*        env,
 
         /* Ok, this write is done maybe activate the next (if any) */
 
-        if (writer_pop(env, descP,
-                       &descP->currentWriter.pid,
-                       &descP->currentWriter.mon,
-                       &descP->currentWriter.ref)) {
+        if (writer_pop(env, descP, &descP->currentWriter)) {
 
             /* There was another one */
 
@@ -13652,10 +13638,8 @@ ERL_NIF_TERM send_check_result(ErlNifEnv*        env,
         /* Some kind of send failure - check what kind */
 
         if ((saveErrno != EAGAIN) && (saveErrno != EINTR)) {
-            ErlNifPid     pid;
-            // ErlNifMonitor mon;
-            ESockMonitor  mon;
-            ERL_NIF_TERM  ref, res;
+            SocketRequestor req;
+            ERL_NIF_TERM    res;
 
             /* 
              * An actual failure - we (and everyone waiting) give up
@@ -13669,15 +13653,17 @@ ERL_NIF_TERM send_check_result(ErlNifEnv*        env,
             res = esock_make_error_errno(env, saveErrno);
 
             if (descP->currentWriterP != NULL) {
+
                 DEMONP("send_check_result -> current writer",
                        env, descP, &descP->currentWriter.mon);
 
-                while (writer_pop(env, descP, &pid, &mon, &ref)) {
+                while (writer_pop(env, descP, &req)) {
                     SSDBG( descP,
-                           ("SOCKET", "send_check_result -> abort %T\r\n", pid) );
-                    esock_send_abort_msg(env, sockRef, ref, res, &pid);
+                           ("SOCKET", "send_check_result -> abort %T\r\n",
+                            req.pid) );
+                    esock_send_abort_msg(env, sockRef, req.ref, res, &req.pid);
                     DEMONP("send_check_result -> pop'ed writer",
-                           env, descP, &mon);
+                           env, descP, &req.mon);
                 }
             }
             
@@ -13852,10 +13838,7 @@ ERL_NIF_TERM recv_update_current_reader(ErlNifEnv*        env,
         DEMONP("recv_update_current_reader -> current reader",
                env, descP, &descP->currentReader.mon);
         
-        if (reader_pop(env, descP,
-                       &descP->currentReader.pid,
-                       &descP->currentReader.mon,
-                       &descP->currentReader.ref)) {
+        if (reader_pop(env, descP, &descP->currentReader)) {
             
             /* There was another one */
             
@@ -13898,21 +13881,20 @@ void recv_error_current_reader(ErlNifEnv*        env,
                                ERL_NIF_TERM      sockRef,
                                ERL_NIF_TERM      reason)
 {
+    SocketRequestor req;
+
     if (descP->currentReaderP != NULL) {
-        ErlNifPid     pid;
-        // ErlNifMonitor mon;
-        ESockMonitor  mon;
-        ERL_NIF_TERM  ref;
 
         DEMONP("recv_error_current_reader -> current reader",
                env, descP, &descP->currentReader.mon);
 
-        while (reader_pop(env, descP, &pid, &mon, &ref)) {
+        while (reader_pop(env, descP, &req)) {
             SSDBG( descP,
-                   ("SOCKET", "recv_error_current_reader -> abort %T\r\n", pid) );
-            esock_send_abort_msg(env, sockRef, ref, reason, &pid);
+                   ("SOCKET", "recv_error_current_reader -> abort %T\r\n",
+                    req.pid) );
+            esock_send_abort_msg(env, sockRef, req.ref, reason, &req.pid);
             DEMONP("recv_error_current_reader -> pop'ed reader",
-                   env, descP, &mon);
+                   env, descP, &req.mon);
         }
     }
 }
@@ -16962,280 +16944,152 @@ int esock_select_cancel(ErlNifEnv*             env,
 
 
 /* ----------------------------------------------------------------------
- *  R e q u e s t   Q u e u e   F u n c t i o n s
+ *  R e q u e s t o r   Q u e u e   F u n c t i o n s
  * ----------------------------------------------------------------------
- */
-
-/* *** acceptor search for pid ***
  *
- * Search for a pid in the acceptor queue.
+ * Since each of these functions (search4pid, push, pop and unqueu
+ * are virtually identical for acceptors, writers and readers, 
+ * we make use of set of declaration macros.
  */
-#if !defined(__WIN32__)
-static
-BOOLEAN_T acceptor_search4pid(ErlNifEnv*        env,
-                              SocketDescriptor* descP,
-                              ErlNifPid*        pid)
-{
-    return qsearch4pid(env, &descP->acceptorsQ, pid);
-}
 
+#if !defined(__WIN32__)
 
-/* *** acceptor push ***
+/* *** search4pid ***
  *
- * Push an acceptor onto the acceptor queue.
- * This happens when we already have atleast one current acceptor.
- */
-static
-ERL_NIF_TERM acceptor_push(ErlNifEnv*        env,
-                           SocketDescriptor* descP,
-                           ErlNifPid         pid,
-                           ERL_NIF_TERM      ref)
-{
-    SocketRequestQueueElement* e    = MALLOC(sizeof(SocketRequestQueueElement));
-    SocketRequestor*           reqP = &e->data;
-    
-    reqP->pid = pid;
-    reqP->ref = enif_make_copy(descP->env, ref);
-    
-    if (MONP("acceptor_push -> acceptor request",
-             env, descP, &pid, &reqP->mon) != 0) {
-        FREE(reqP);
-        return esock_make_error(env, atom_exmon);
-    }
-    
-    qpush(&descP->acceptorsQ, e);
-    
-    // THIS IS OK => MAKES THE CALLER WAIT FOR ITS TURN
-    return esock_make_error(env, esock_atom_eagain);
-}
-
-
-/* *** acceptor pop ***
+ * Search for a pid in the requestor (acceptor, writer, or reader) queue.
  *
- * Pop an acceptor from the acceptor queue.
  */
-static
-BOOLEAN_T acceptor_pop(ErlNifEnv*        env,
-                       SocketDescriptor* descP,
-                       ErlNifPid*        pid,
-                       // ErlNifMonitor*    mon,
-                       ESockMonitor*     mon,
-                       ERL_NIF_TERM*     ref)
-{
-    SocketRequestQueueElement* e = qpop(&descP->acceptorsQ);
 
-    if (e != NULL) {
-        *pid = e->data.pid;
-        *mon = e->data.mon;
-        *ref = e->data.ref;
-        FREE(e);
-        return TRUE;
-    } else {
-        /* (acceptors) Queue was empty */
-        // *pid = NULL; we have no null value for pids
-        // *mon = NULL; we have no null value for monitors
-        *ref = esock_atom_undefined; // Just in case
-        return FALSE;
+#define REQ_SEARCH4PID_FUNCS                       \
+    REQ_SEARCH4PID_FUNC_DECL(acceptor, acceptorsQ) \
+    REQ_SEARCH4PID_FUNC_DECL(writer,   writersQ)   \
+    REQ_SEARCH4PID_FUNC_DECL(reader,   readersQ)
+
+#define REQ_SEARCH4PID_FUNC_DECL(F, Q)                  \
+    static                                              \
+    BOOLEAN_T F##_search4pid(ErlNifEnv*        env,     \
+                             SocketDescriptor* descP,   \
+                             ErlNifPid*        pid)     \
+    {                                                   \
+        return qsearch4pid(env, &descP->Q, pid);        \
     }
-    
-}
+REQ_SEARCH4PID_FUNCS
+#undef REQ_SEARCH4PID_FUNC_DECL
 
 
-/* *** acceptor unqueue ***
+/* *** push ***
  *
- * Remove an acceptor from the acceptor queue.
- */
-static
-BOOLEAN_T acceptor_unqueue(ErlNifEnv*        env,
-                           SocketDescriptor* descP,
-                           const ErlNifPid*  pid)
-{
-    return qunqueue(env, descP, "qunqueue -> waiting acceptor",
-                    &descP->acceptorsQ, pid);
-}
-
-
-
-/* *** writer search for pid ***
+ * Push a requestor (acceptor, writer, or reader) onto its queue.
+ * This happens when we already have a current request (of its type).
  *
- * Search for a pid in the writer queue.
  */
-static
-BOOLEAN_T writer_search4pid(ErlNifEnv*        env,
-                            SocketDescriptor* descP,
-                            ErlNifPid*        pid)
-{
-    return qsearch4pid(env, &descP->writersQ, pid);
-}
-
 
-/* *** writer push ***
- *
- * Push an writer onto the writer queue.
- * This happens when we already have atleast one current writer.
- */
-static
-ERL_NIF_TERM writer_push(ErlNifEnv*        env,
-                         SocketDescriptor* descP,
-                         ErlNifPid         pid,
-                         ERL_NIF_TERM      ref)
-{
-    SocketRequestQueueElement* e    = MALLOC(sizeof(SocketRequestQueueElement));
-    SocketRequestor*           reqP = &e->data;
-    
-    reqP->pid = pid;
-    reqP->ref = enif_make_copy(descP->env, ref);
-    
-    if (MONP("writer_push -> writer request",
-             env, descP, &pid, &reqP->mon) != 0) {
-        FREE(reqP);
-        return esock_make_error(env, atom_exmon);
+#define REQ_PUSH_FUNCS                       \
+    REQ_PUSH_FUNC_DECL(acceptor, acceptorsQ) \
+    REQ_PUSH_FUNC_DECL(writer,   writersQ)   \
+    REQ_PUSH_FUNC_DECL(reader,   readersQ)
+
+#define REQ_PUSH_FUNC_DECL(F, Q)                                        \
+    static                                                              \
+    ERL_NIF_TERM F##_push(ErlNifEnv*        env,                        \
+                          SocketDescriptor* descP,                      \
+                          ErlNifPid         pid,                        \
+                          ERL_NIF_TERM      ref)                        \
+    {                                                                   \
+        SocketRequestQueueElement* e    = MALLOC(sizeof(SocketRequestQueueElement)); \
+        SocketRequestor*           reqP = &e->data;                     \
+                                                                        \
+        reqP->pid = pid;                                                \
+        reqP->ref = enif_make_copy(descP->env, ref);                    \
+                                                                        \
+        if (MONP("reader_push -> " #F " request",                       \
+                 env, descP, &pid, &reqP->mon) != 0) {                  \
+            FREE(reqP);                                                 \
+            return esock_make_error(env, atom_exmon);                   \
+        }                                                               \
+                                                                        \
+        qpush(&descP->Q, e);                                            \
+                                                                        \
+        return esock_make_error(env, esock_atom_eagain);                \
     }
-    
-    qpush(&descP->writersQ, e);
-    
-    // THIS IS OK => MAKES THE CALLER WAIT FOR ITS TURN
-    return esock_make_error(env, esock_atom_eagain);
-}
+REQ_PUSH_FUNCS
+#undef REQ_PUSH_FUNC_DECL
 
 
-/* *** writer pop ***
+/* *** pop ***
+ *
+ * Pop a requestor (acceptor, writer, or reader) from its queue.
  *
- * Pop an writer from the writer queue.
  */
-static
-BOOLEAN_T writer_pop(ErlNifEnv*        env,
-                     SocketDescriptor* descP,
-                     ErlNifPid*        pid,
-                     // ErlNifMonitor*    mon,
-                     ESockMonitor*     mon,
-                     ERL_NIF_TERM*     ref)
-{
-    SocketRequestQueueElement* e = qpop(&descP->writersQ);
-
-    if (e != NULL) {
-        *pid = e->data.pid;
-        *mon = e->data.mon;
-        *ref = e->data.ref; // At this point the ref has already been copied (env)
-        FREE(e);
-        return TRUE;
-    } else {
-        /* (writers) Queue was empty */
-        // *pid = NULL; we have no null value for pids
-        // *mon = NULL; we have no null value for monitors
-        *ref = esock_atom_undefined; // Just in case
-        return FALSE;
+#define REQ_POP_FUNCS                       \
+    REQ_POP_FUNC_DECL(acceptor, acceptorsQ) \
+    REQ_POP_FUNC_DECL(writer,   writersQ)   \
+    REQ_POP_FUNC_DECL(reader,   readersQ)
+
+#define REQ_POP_FUNC_DECL(F, Q)                 \
+    static                                      \
+    BOOLEAN_T F##_pop(ErlNifEnv*        env,    \
+                      SocketDescriptor* descP,  \
+                      SocketRequestor*  reqP)   \
+    {                                           \
+        return requestor_pop(&descP->Q, reqP);  \
     }
-    
-}
+REQ_POP_FUNCS
+#undef REQ_POP_FUNC_DECL
 
 
-/* *** writer unqueue ***
+/* *** unqueue ***
  *
- * Remove an writer from the writer queue.
- */
-static
-BOOLEAN_T writer_unqueue(ErlNifEnv*        env,
-                         SocketDescriptor* descP,
-                         const ErlNifPid*  pid)
-{
-    return qunqueue(env, descP, "qunqueue -> waiting writer",
-                    &descP->writersQ, pid);
-}
-
-
-
-/* *** reader search for pid ***
+ * Remove a requestor (acceptor, writer, or reader) from its queue.
  *
- * Search for a pid in the reader queue.
  */
-static
-BOOLEAN_T reader_search4pid(ErlNifEnv*        env,
-                            SocketDescriptor* descP,
-                            ErlNifPid*        pid)
-{
-    return qsearch4pid(env, &descP->readersQ, pid);
-}
 
+#define REQ_UNQUEUE_FUNCS                       \
+    REQ_UNQUEUE_FUNC_DECL(acceptor, acceptorsQ) \
+    REQ_UNQUEUE_FUNC_DECL(writer,   writersQ)   \
+    REQ_UNQUEUE_FUNC_DECL(reader,   readersQ)
 
-/* *** reader push ***
- *
- * Push an reader onto the raeder queue.
- * This happens when we already have atleast one current reader.
- */
-static
-ERL_NIF_TERM reader_push(ErlNifEnv*        env,
-                         SocketDescriptor* descP,
-                         ErlNifPid         pid,
-                         ERL_NIF_TERM      ref)
-{
-    SocketRequestQueueElement* e    = MALLOC(sizeof(SocketRequestQueueElement));
-    SocketRequestor*           reqP = &e->data;
-    
-    reqP->pid = pid;
-    reqP->ref = enif_make_copy(descP->env, ref);
-    
-    if (MONP("reader_push -> reader request",
-             env, descP, &pid, &reqP->mon) != 0) {
-        FREE(reqP);
-        return esock_make_error(env, atom_exmon);
+#define REQ_UNQUEUE_FUNC_DECL(F, Q)                             \
+    static                                                      \
+    BOOLEAN_T F##_unqueue(ErlNifEnv*        env,                \
+                          SocketDescriptor* descP,              \
+                          const ErlNifPid*  pid)                \
+    {                                                           \
+        return qunqueue(env, descP, "qunqueue -> waiting " #F,  \
+                        &descP->Q, pid);                        \
     }
-    
-    qpush(&descP->readersQ, e);
-    
-    // THIS IS OK => MAKES THE CALLER WAIT FOR ITS TURN
-    return esock_make_error(env, esock_atom_eagain);
-}
+REQ_UNQUEUE_FUNCS
+#undef REQ_UNQUEUE_FUNC_DECL
+
 
 
-/* *** reader pop ***
+/* *** requestor pop ***
  *
- * Pop an writer from the reader queue.
+ * Pop an requestor from its queue.
  */
 static
-BOOLEAN_T reader_pop(ErlNifEnv*        env,
-                     SocketDescriptor* descP,
-                     ErlNifPid*        pid,
-                     // ErlNifMonitor*    mon,
-                     ESockMonitor*    mon,
-                     ERL_NIF_TERM*     ref)
+BOOLEAN_T requestor_pop(SocketRequestQueue* q,
+                        SocketRequestor*    reqP)
 {
-    SocketRequestQueueElement* e = qpop(&descP->readersQ);
+    SocketRequestQueueElement* e = qpop(q);
 
     if (e != NULL) {
-        *pid = e->data.pid;
-        *mon = e->data.mon;
-        *ref = e->data.ref; // At this point the ref has already been copied (env)
+        reqP->pid = e->data.pid;
+        reqP->mon = e->data.mon;
+        reqP->ref = e->data.ref;
         FREE(e);
         return TRUE;
     } else {
-        /* (readers) Queue was empty */
-        // *pid = NULL; we have no null value for pids
-        // *mon = NULL; we have no null value for monitors
-        *ref = esock_atom_undefined; // Just in case
+        /* (writers) Queue was empty */
+        enif_set_pid_undefined(&reqP->pid);
+        // *reqP->mon = NULL; we have no null value for monitors
+        reqP->ref = esock_atom_undefined; // Just in case
         return FALSE;
     }
     
 }
 
 
-/* *** reader unqueue ***
- *
- * Remove an reader from the reader queue.
- */
-static
-BOOLEAN_T reader_unqueue(ErlNifEnv*        env,
-                         SocketDescriptor* descP,
-                         const ErlNifPid*  pid)
-{
-    return qunqueue(env, descP, "qunqueue -> waiting reader",
-                    &descP->readersQ, pid);
-}
-
-
-
-
-
 static
 BOOLEAN_T qsearch4pid(ErlNifEnv*          env,
                       SocketRequestQueue* q,
@@ -17997,10 +17851,7 @@ void socket_down_acceptor(ErlNifEnv*        env,
                        "socket_down_acceptor -> "
                        "current acceptor - try pop the queue\r\n") );
         
-        if (acceptor_pop(env, descP,
-                         &descP->currentAcceptor.pid,
-                         &descP->currentAcceptor.mon,
-                         &descP->currentAcceptor.ref)) {
+        if (acceptor_pop(env, descP, &descP->currentAcceptor)) {
             int res;
             
             /* There was another one, so we will still be in accepting state */
@@ -18063,10 +17914,7 @@ void socket_down_writer(ErlNifEnv*        env,
                        "socket_down_writer -> "
                        "current writer - try pop the queue\r\n") );
         
-        if (writer_pop(env, descP,
-                       &descP->currentWriter.pid,
-                       &descP->currentWriter.mon,
-                       &descP->currentWriter.ref)) {
+        if (writer_pop(env, descP, &descP->currentWriter)) {
             int res;
             
             /* There was another one */
@@ -18127,10 +17975,7 @@ void socket_down_reader(ErlNifEnv*        env,
                        "socket_down_reader -> "
                        "current reader - try pop the queue\r\n") );
         
-        if (reader_pop(env, descP,
-                       &descP->currentReader.pid,
-                       &descP->currentReader.mon,
-                       &descP->currentReader.ref)) {
+        if (reader_pop(env, descP, &descP->currentReader)) {
             int res;
             
             /* There was another one */