Merge PR-2127 from sverker/erts/enif_make_monitor_term/OTP-15362

Add enif_make_monitor_term

5 files changed, 39 insertions, 0 deletions

diff --git a/erts/doc/src/erl_nif.xml b/erts/doc/src/erl_nif.xml
index 34042cb4de..95b7188882 100644
--- a/erts/doc/src/erl_nif.xml
+++ b/erts/doc/src/erl_nif.xml
@@ -2217,6 +2217,18 @@ enif_inspect_iovec(env, max_elements, term, &tail, &iovec);
     </func>
 
     <func>
+      <name since="OTP @OTP-15362@"><ret>ERL_NIF_TERM</ret>
+        <nametext>enif_make_monitor_term(ErlNifEnv* env, const ErlNifMonitor* mon)</nametext></name>
+      <fsummary>Make monitor term from the given monitor identifier.</fsummary>
+      <desc>
+        <p>Creates a term identifying the given monitor received from
+	<seealso marker="#enif_monitor_process"><c>enif_monitor_process</c>
+	</seealso>.</p>
+	<p>This function is primarily intended for debugging purpose.</p>
+      </desc>
+    </func>
+
+    <func>
       <name since="OTP R14B"><ret>unsigned char *</ret><nametext>enif_make_new_binary(ErlNifEnv*
         env, size_t size, ERL_NIF_TERM* termp)</nametext></name>
       <fsummary>Allocate and create a new binary term.</fsummary>
diff --git a/erts/emulator/beam/erl_nif.c b/erts/emulator/beam/erl_nif.c
index a48d0391f6..b762e0f6e7 100644
--- a/erts/emulator/beam/erl_nif.c
+++ b/erts/emulator/beam/erl_nif.c
@@ -3362,6 +3362,12 @@ int enif_monitor_process(ErlNifEnv* env, void* obj, const ErlNifPid* target_pid,
     return 0;
 }
 
+ERL_NIF_TERM enif_make_monitor_term(ErlNifEnv* env, const ErlNifMonitor* monitor)
+{
+    Eterm* hp = alloc_heap(env, ERTS_REF_THING_SIZE);
+    return erts_driver_monitor_to_ref(hp, monitor);
+}
+
 int enif_demonitor_process(ErlNifEnv* env, void* obj, const ErlNifMonitor* monitor)
 {
     ErtsResource* rsrc = DATA_TO_RESOURCE(obj);
diff --git a/erts/emulator/beam/erl_nif_api_funcs.h b/erts/emulator/beam/erl_nif_api_funcs.h
index 129166562d..4ea6a2f7b0 100644
--- a/erts/emulator/beam/erl_nif_api_funcs.h
+++ b/erts/emulator/beam/erl_nif_api_funcs.h
@@ -211,6 +211,7 @@ 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));
+ERL_NIF_API_FUNC_DECL(ERL_NIF_TERM,enif_make_monitor_term,(ErlNifEnv* env, const ErlNifMonitor*));
 
 
 /*
@@ -396,6 +397,7 @@ ERL_NIF_API_FUNC_DECL(int,enif_select_x,(ErlNifEnv* env, ErlNifEvent e, enum Erl
 #  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)
+#  define enif_make_monitor_term ERL_NIF_API_FUNC_MACRO(enif_make_monitor_term)
 
 /*
 ** ADD NEW ENTRIES HERE (before this comment)
diff --git a/erts/emulator/test/nif_SUITE.erl b/erts/emulator/test/nif_SUITE.erl
index 0d0930e124..75b3cd2c14 100644
--- a/erts/emulator/test/nif_SUITE.erl
+++ b/erts/emulator/test/nif_SUITE.erl
@@ -822,8 +822,11 @@ demonitor_process(Config) ->
                      end),
     R_ptr = alloc_monitor_resource_nif(),
     {0,MonBin1} = monitor_process_nif(R_ptr, Pid, true, self()),
+    MonTerm1 = make_monitor_term_nif(MonBin1),
     [R_ptr] = monitored_by(Pid),
     {0,MonBin2} = monitor_process_nif(R_ptr, Pid, true, self()),
+    MonTerm2 = make_monitor_term_nif(MonBin2),
+    true = (MonTerm1 =/= MonTerm2),
     [R_ptr, R_ptr] = monitored_by(Pid),
     0 = demonitor_process_nif(R_ptr, MonBin1),
     [R_ptr] = monitored_by(Pid),
@@ -837,6 +840,10 @@ demonitor_process(Config) ->
     {R_ptr, _, 1} = last_resource_dtor_call(),
     [] = monitored_by(Pid),
     Pid ! return,
+
+    erlang:garbage_collect(),
+    true = (MonTerm1 =/= MonTerm2),
+    io:format("MonTerm1 = ~p\nMonTerm2 = ~p\n", [MonTerm1, MonTerm2]),
     ok.
 
 
@@ -3421,6 +3428,7 @@ alloc_monitor_resource_nif() -> ?nif_stub.
 monitor_process_nif(_,_,_,_) -> ?nif_stub.
 demonitor_process_nif(_,_) -> ?nif_stub.
 compare_monitors_nif(_,_) -> ?nif_stub.
+make_monitor_term_nif(_) -> ?nif_stub.
 monitor_frenzy_nif(_,_,_,_) -> ?nif_stub.
 ioq_nif(_) -> ?nif_stub.
 ioq_nif(_,_) -> ?nif_stub.
diff --git a/erts/emulator/test/nif_SUITE_data/nif_SUITE.c b/erts/emulator/test/nif_SUITE_data/nif_SUITE.c
index 21af4b05b3..af2d062857 100644
--- a/erts/emulator/test/nif_SUITE_data/nif_SUITE.c
+++ b/erts/emulator/test/nif_SUITE_data/nif_SUITE.c
@@ -2847,6 +2847,16 @@ static ERL_NIF_TERM compare_monitors_nif(ErlNifEnv* env, int argc, const ERL_NIF
     return enif_make_int(env, enif_compare_monitors(&m1, &m2));
 }
 
+static ERL_NIF_TERM make_monitor_term_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
+{
+    ErlNifMonitor m;
+    if (!get_monitor(env, argv[0], &m)) {
+        return enif_make_badarg(env);
+    }
+
+    return enif_make_monitor_term(env, &m);
+}
+
 
 /*********** monitor_frenzy ************/
 
@@ -3596,6 +3606,7 @@ static ErlNifFunc nif_funcs[] =
     {"monitor_process_nif", 4, monitor_process_nif},
     {"demonitor_process_nif", 2, demonitor_process_nif},
     {"compare_monitors_nif", 2, compare_monitors_nif},
+    {"make_monitor_term_nif", 1, make_monitor_term_nif},
     {"monitor_frenzy_nif", 4, monitor_frenzy_nif},
     {"whereis_send", 3, whereis_send},
     {"whereis_term", 2, whereis_term},