Merge PR-2084 from sverker/erts/enif_select-custom-msg OTP-15349

Custom message format for enif_select

6 files changed, 39 insertions, 18 deletions

diff --git a/erts/emulator/beam/erl_drv_nif.h b/erts/emulator/beam/erl_drv_nif.h
index 9ef7c39d41..a5ecbfff06 100644
--- a/erts/emulator/beam/erl_drv_nif.h
+++ b/erts/emulator/beam/erl_drv_nif.h
@@ -54,7 +54,8 @@ enum ErlNifSelectFlags {
     ERL_NIF_SELECT_READ      = (1 << 0),
     ERL_NIF_SELECT_WRITE     = (1 << 1),
     ERL_NIF_SELECT_STOP      = (1 << 2),
-    ERL_NIF_SELECT_CANCEL    = (1 << 3)
+    ERL_NIF_SELECT_CANCEL    = (1 << 3),
+    ERL_NIF_SELECT_CUSTOM_MSG= (1 << 4)
 };
 
 /*
diff --git a/erts/emulator/beam/erl_message.c b/erts/emulator/beam/erl_message.c
index a3274d7443..942bec84cf 100644
--- a/erts/emulator/beam/erl_message.c
+++ b/erts/emulator/beam/erl_message.c
@@ -532,9 +532,7 @@ erts_try_alloc_message_on_heap(Process *pp,
 
     if ((*psp) & ERTS_PSFLGS_VOLATILE_HEAP)
 	goto in_message_fragment;
-    else if (
-	*plp & ERTS_PROC_LOCK_MAIN
-	) {
+    else if (*plp & ERTS_PROC_LOCK_MAIN) {
     try_on_heap:
 	if (((*psp) & ERTS_PSFLGS_VOLATILE_HEAP)
 	    || (pp->flags & F_DISABLE_GC)
diff --git a/erts/emulator/beam/erl_nif.c b/erts/emulator/beam/erl_nif.c
index 7339aa8874..a48d0391f6 100644
--- a/erts/emulator/beam/erl_nif.c
+++ b/erts/emulator/beam/erl_nif.c
@@ -707,6 +707,29 @@ error:
     return reds;
 }
 
+/** @brief Create a message with the content of process independent \c msg_env.
+ *  Invalidates \c msg_env.
+ */
+ErtsMessage* erts_create_message_from_nif_env(ErlNifEnv* msg_env)
+{
+    struct enif_msg_environment_t* menv = (struct enif_msg_environment_t*)msg_env;
+    ErtsMessage* mp;
+
+    flush_env(msg_env);
+    mp = erts_alloc_message(0, NULL);
+    mp->data.heap_frag = menv->env.heap_frag;
+    ASSERT(mp->data.heap_frag == MBUF(&menv->phony_proc));
+    if (mp->data.heap_frag != NULL) {
+        /* Move all offheap's from phony proc to the first fragment.
+           Quick and dirty... */
+        ASSERT(!is_offheap(&mp->data.heap_frag->off_heap));
+        mp->data.heap_frag->off_heap = MSO(&menv->phony_proc);
+        clear_offheap(&MSO(&menv->phony_proc));
+        menv->env.heap_frag = NULL;
+        MBUF(&menv->phony_proc) = NULL;
+    }
+    return mp;
+}
 
 int enif_send(ErlNifEnv* env, const ErlNifPid* to_pid,
 	      ErlNifEnv* msg_env, ERL_NIF_TERM msg)
@@ -803,20 +826,8 @@ int enif_send(ErlNifEnv* env, const ErlNifPid* to_pid,
             }
 #endif
         }
-        flush_env(msg_env);
-        mp = erts_alloc_message(0, NULL);
+        mp = erts_create_message_from_nif_env(msg_env);
         ERL_MESSAGE_TOKEN(mp) = token;
-        mp->data.heap_frag = menv->env.heap_frag;
-        ASSERT(mp->data.heap_frag == MBUF(&menv->phony_proc));
-        if (mp->data.heap_frag != NULL) {
-            /* Move all offheap's from phony proc to the first fragment.
-               Quick and dirty... */
-            ASSERT(!is_offheap(&mp->data.heap_frag->off_heap));
-            mp->data.heap_frag->off_heap = MSO(&menv->phony_proc);
-            clear_offheap(&MSO(&menv->phony_proc));
-            menv->env.heap_frag = NULL;
-            MBUF(&menv->phony_proc) = NULL;
-        }
     } else {
         erts_literal_area_t litarea;
 	ErlOffHeap *ohp;
diff --git a/erts/emulator/beam/erl_nif.h b/erts/emulator/beam/erl_nif.h
index 58a217c20b..3fd1a8fd4c 100644
--- a/erts/emulator/beam/erl_nif.h
+++ b/erts/emulator/beam/erl_nif.h
@@ -54,7 +54,7 @@
 ** 2.13: 20.1 add enif_ioq
 ** 2.14: 21.0 add enif_ioq_peek_head, enif_(mutex|cond|rwlock|thread)_name
 **                enif_vfprintf, enif_vsnprintf, enif_make_map_from_arrays
-** 2.15: 22.0 ERL_NIF_SELECT_CANCEL
+** 2.15: 22.0 ERL_NIF_SELECT_CANCEL, enif_select_(read|write)
 */
 #define ERL_NIF_MAJOR_VERSION 2
 #define ERL_NIF_MINOR_VERSION 15
diff --git a/erts/emulator/beam/erl_nif_api_funcs.h b/erts/emulator/beam/erl_nif_api_funcs.h
index 81f64f2390..129166562d 100644
--- a/erts/emulator/beam/erl_nif_api_funcs.h
+++ b/erts/emulator/beam/erl_nif_api_funcs.h
@@ -210,6 +210,9 @@ ERL_NIF_API_FUNC_DECL(int,enif_vsnprintf,(char*, size_t, const char *fmt, va_lis
 
 ERL_NIF_API_FUNC_DECL(int,enif_make_map_from_arrays,(ErlNifEnv *env, ERL_NIF_TERM keys[], ERL_NIF_TERM values[], size_t cnt, ERL_NIF_TERM *map_out));
 
+ERL_NIF_API_FUNC_DECL(int,enif_select_x,(ErlNifEnv* env, ErlNifEvent e, enum ErlNifSelectFlags flags, void* obj, const ErlNifPid* pid, ERL_NIF_TERM msg, ErlNifEnv* msg_env));
+
+
 /*
 ** ADD NEW ENTRIES HERE (before this comment) !!!
 */
@@ -392,6 +395,7 @@ ERL_NIF_API_FUNC_DECL(int,enif_make_map_from_arrays,(ErlNifEnv *env, ERL_NIF_TER
 #  define enif_vfprintf ERL_NIF_API_FUNC_MACRO(enif_vfprintf)
 #  define enif_vsnprintf ERL_NIF_API_FUNC_MACRO(enif_vsnprintf)
 #  define enif_make_map_from_arrays ERL_NIF_API_FUNC_MACRO(enif_make_map_from_arrays)
+#  define enif_select_x ERL_NIF_API_FUNC_MACRO(enif_select_x)
 
 /*
 ** ADD NEW ENTRIES HERE (before this comment)
@@ -623,6 +627,12 @@ static ERL_NIF_INLINE ERL_NIF_TERM enif_make_list9(ErlNifEnv* env,
 #ifndef enif_make_pid
 
 #  define enif_make_pid(ENV, PID) ((void)(ENV),(const ERL_NIF_TERM)((PID)->pid))
+#  define enif_select_read(ENV, E, OBJ, PID, MSG, MSG_ENV) \
+    enif_select_x(ENV, E, ERL_NIF_SELECT_READ | ERL_NIF_SELECT_CUSTOM_MSG, \
+                  OBJ, PID, MSG, MSG_ENV)
+#  define enif_select_write(ENV, E, OBJ, PID, MSG, MSG_ENV) \
+    enif_select_x(ENV, E, ERL_NIF_SELECT_WRITE | ERL_NIF_SELECT_CUSTOM_MSG, \
+                  OBJ, PID, MSG, MSG_ENV)
 
 #if SIZEOF_LONG == 8
 #  define enif_get_int64 enif_get_long
diff --git a/erts/emulator/beam/global.h b/erts/emulator/beam/global.h
index 77b5a3ca05..9eb7b58dbb 100644
--- a/erts/emulator/beam/global.h
+++ b/erts/emulator/beam/global.h
@@ -131,6 +131,7 @@ extern Eterm erts_nif_call_function(Process *p, Process *tracee,
 
 int erts_call_dirty_nif(ErtsSchedulerData *esdp, Process *c_p,
 			BeamInstr *I, Eterm *reg);
+ErtsMessage* erts_create_message_from_nif_env(ErlNifEnv* msg_env);
 
 
 /* Driver handle (wrapper for old plain handle) */