From b31750711daa35011c62898d2eb424332e170bcc Mon Sep 17 00:00:00 2001
From: Sverker Eriksson <sverker@erlang.org>
Date: Thu, 1 Mar 2018 16:36:17 +0100
Subject: erts: Refactor DistEntry.status flags into a state

Just to simplify and get 4 distinctive states
IDLE, PENDING, CONNECTED and EXITING.

The old possible flag combos were:
0
PENDING
CONNECTED
CONNECTED|EXITING
EXITING

The two EXITING states did not serve any purpose
other then as a slight optimization in monitor_node(_,false,_)
to shortcut EXITING when there can be no monitors.
---
 erts/emulator/beam/erl_node_tables.c | 23 +++++++++++++----------
 1 file changed, 13 insertions(+), 10 deletions(-)

(limited to 'erts/emulator/beam/erl_node_tables.c')

diff --git a/erts/emulator/beam/erl_node_tables.c b/erts/emulator/beam/erl_node_tables.c
index 088b087ebb..9871965ba6 100644
--- a/erts/emulator/beam/erl_node_tables.c
+++ b/erts/emulator/beam/erl_node_tables.c
@@ -170,7 +170,7 @@ dist_table_alloc(void *dep_tmpl)
     dep->cid				= NIL;
     erts_atomic_init_nob(&dep->input_handler, (erts_aint_t) NIL);
     dep->connection_id			= 0;
-    dep->status				= 0;
+    dep->state				= ERTS_DE_STATE_IDLE;
     dep->flags				= 0;
     dep->version			= 0;
 
@@ -223,7 +223,7 @@ dist_table_free(void *vdep)
     DistEntry *dep = (DistEntry *) vdep;
 
     ASSERT(de_refc_read(dep, -1) == -1);
-    ASSERT(dep->status == 0);
+    ASSERT(dep->state == ERTS_DE_STATE_IDLE);
     ASSERT(is_nil(dep->cid));
     ASSERT(dep->nlinks == NULL);
     ASSERT(dep->node_links == NULL);
@@ -556,14 +556,18 @@ erts_set_dist_entry_not_connected(DistEntry *dep)
 
     ASSERT(dep != erts_this_dist_entry);
 
-    if (dep->status & ERTS_DE_SFLG_PENDING) {
+    if (dep->state == ERTS_DE_STATE_PENDING) {
         ASSERT(is_nil(dep->cid));
         ASSERT(erts_no_of_pending_dist_entries > 0);
         erts_no_of_pending_dist_entries--;
         head = &erts_pending_dist_entries;
+
+        // Todo: Is this really ok? Must be not wait for links and monitors
+        // to be fired before we can allow another connection.
+        dep->state = ERTS_DE_STATE_IDLE;
     }
     else {
-        ASSERT(dep->status != 0);
+        ASSERT(dep->state != ERTS_DE_STATE_IDLE);
         ASSERT(is_internal_port(dep->cid) || is_internal_pid(dep->cid));
         if (dep->flags & DFLAG_PUBLISHED) {
             ASSERT(erts_no_of_visible_dist_entries > 0);
@@ -575,6 +579,7 @@ erts_set_dist_entry_not_connected(DistEntry *dep)
             erts_no_of_hidden_dist_entries--;
             head = &erts_hidden_dist_entries;
         }
+        dep->state = ERTS_DE_STATE_EXITING;
     }
 
     if(dep->prev) {
@@ -588,7 +593,6 @@ erts_set_dist_entry_not_connected(DistEntry *dep)
     if(dep->next)
 	dep->next->prev = dep->prev;
 
-    dep->status &= ~(ERTS_DE_SFLG_PENDING | ERTS_DE_SFLG_CONNECTED);
     dep->flags = 0;
     dep->prev = NULL;
     dep->cid = NIL;
@@ -610,7 +614,7 @@ erts_set_dist_entry_pending(DistEntry *dep)
     erts_rwmtx_rwlock(&erts_dist_table_rwmtx);
 
     ASSERT(dep != erts_this_dist_entry);
-    ASSERT(dep->status == 0);
+    ASSERT(dep->state == ERTS_DE_STATE_IDLE);
     ASSERT(is_nil(dep->cid));
 
     if(dep->prev) {
@@ -627,7 +631,7 @@ erts_set_dist_entry_pending(DistEntry *dep)
 
     erts_no_of_not_connected_dist_entries--;
 
-    dep->status = ERTS_DE_SFLG_PENDING;
+    dep->state = ERTS_DE_STATE_PENDING;
     dep->flags = (DFLAG_DIST_MANDATORY | DFLAG_DIST_HOPEFULLY | DFLAG_NO_MAGIC);
     dep->connection_id = (dep->connection_id + 1) & ERTS_DIST_CON_ID_MASK;
 
@@ -652,7 +656,7 @@ erts_set_dist_entry_connected(DistEntry *dep, Eterm cid, Uint flags)
 
     ASSERT(dep != erts_this_dist_entry);
     ASSERT(is_nil(dep->cid));
-    ASSERT(dep->status & ERTS_DE_SFLG_PENDING);
+    ASSERT(dep->state == ERTS_DE_STATE_PENDING);
     ASSERT(is_internal_port(cid) || is_internal_pid(cid));
 
     if(dep->prev) {
@@ -670,8 +674,7 @@ erts_set_dist_entry_connected(DistEntry *dep, Eterm cid, Uint flags)
     ASSERT(erts_no_of_pending_dist_entries > 0);
     erts_no_of_pending_dist_entries--;
 
-    dep->status &= ~ERTS_DE_SFLG_PENDING;
-    dep->status |= ERTS_DE_SFLG_CONNECTED;
+    dep->state = ERTS_DE_STATE_CONNECTED;
     dep->flags = flags & ~DFLAG_NO_MAGIC;
     dep->cid = cid;
     erts_atomic_set_nob(&dep->input_handler,
-- 
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