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-rw-r--r--erts/doc/src/erl_nif.xml20
-rw-r--r--erts/emulator/beam/erl_nif.c49
-rw-r--r--erts/emulator/beam/erl_nif.h3
-rw-r--r--erts/emulator/beam/erl_nif_api_funcs.h2
-rw-r--r--erts/emulator/test/nif_SUITE.erl23
-rw-r--r--erts/emulator/test/nif_SUITE_data/nif_SUITE.c9
6 files changed, 103 insertions, 3 deletions
diff --git a/erts/doc/src/erl_nif.xml b/erts/doc/src/erl_nif.xml
index ef3cdb89e9..23f0c66429 100644
--- a/erts/doc/src/erl_nif.xml
+++ b/erts/doc/src/erl_nif.xml
@@ -367,6 +367,8 @@ return term;</code>
<c>enif_ioq_deq()</c></seealso></item>
<item><seealso marker="#enif_ioq_peek">
<c>enif_ioq_peek()</c></seealso></item>
+ <item><seealso marker="#enif_ioq_peek_head">
+ <c>enif_ioq_peek_head()</c></seealso></item>
<item><seealso marker="#enif_inspect_iovec">
<c>enif_inspect_iovec()</c></seealso></item>
<item><seealso marker="#enif_free_iovec">
@@ -1683,8 +1685,7 @@ enif_inspect_iovec(env, max_elements, term, &amp;tail, &amp;iovec);
<fsummary>Peek inside the IO Queue</fsummary>
<desc>
<p>Get the I/O queue as a pointer to an array of <c>SysIOVec</c>s.
- It also returns the number of elements in <c>iovlen</c>.
- This is the only way to get data out of the queue.</p>
+ It also returns the number of elements in <c>iovlen</c>.</p>
<p>Nothing is removed from the queue by this function, that must be done
with <seealso marker="#enif_ioq_deq"><c>enif_ioq_deq</c></seealso>.</p>
<p>The returned array is suitable to use with the Unix system
@@ -1693,6 +1694,21 @@ enif_inspect_iovec(env, max_elements, term, &amp;tail, &amp;iovec);
</func>
<func>
+ <name><ret>int</ret>
+ <nametext>enif_ioq_peek_head(ErlNifEnv *env, ErlNifIOQueue *q, size_t *size, ERL_NIF_TERM *bin_term)</nametext></name>
+ <fsummary>Peek the head of the IO Queue.</fsummary>
+ <desc>
+ <p>Get the head of the IO Queue as a binary term.</p>
+ <p>If <c>size</c> is not <c>NULL</c>, the size of the head is placed
+ there.</p>
+ <p>Nothing is removed from the queue by this function, that must be done
+ with <seealso marker="#enif_ioq_deq"><c>enif_ioq_deq</c></seealso>.</p>
+ <p>Returns <c>true</c> on success, or <c>false</c> if the queue is
+ empty.</p>
+ </desc>
+ </func>
+
+ <func>
<name><ret>size_t</ret>
<nametext>enif_ioq_size(ErlNifIOQueue *q)</nametext></name>
<fsummary>Get the current size of the IO Queue</fsummary>
diff --git a/erts/emulator/beam/erl_nif.c b/erts/emulator/beam/erl_nif.c
index dbcc894ac9..abb490cf9c 100644
--- a/erts/emulator/beam/erl_nif.c
+++ b/erts/emulator/beam/erl_nif.c
@@ -3605,6 +3605,55 @@ int enif_ioq_deq(ErlNifIOQueue *q, size_t elems, size_t *size)
return 1;
}
+int enif_ioq_peek_head(ErlNifEnv *env, ErlNifIOQueue *q, size_t *size, ERL_NIF_TERM *bin_term) {
+ SysIOVec *iov_entry;
+ Binary *ref_bin;
+
+ if (q->size == 0) {
+ return 0;
+ }
+
+ ASSERT(q->b_head != q->b_tail && q->v_head != q->v_tail);
+
+ ref_bin = &q->b_head[0]->nif;
+ iov_entry = &q->v_head[0];
+
+ if (size != NULL) {
+ *size = iov_entry->iov_len;
+ }
+
+ if (iov_entry->iov_len > ERL_ONHEAP_BIN_LIMIT) {
+ ProcBin *pb = (ProcBin*)alloc_heap(env, PROC_BIN_SIZE);
+
+ pb->thing_word = HEADER_PROC_BIN;
+ pb->next = MSO(env->proc).first;
+ pb->val = ref_bin;
+ pb->flags = 0;
+
+ ASSERT((byte*)iov_entry->iov_base >= (byte*)ref_bin->orig_bytes);
+ ASSERT(iov_entry->iov_len <= ref_bin->orig_size);
+
+ pb->bytes = (byte*)iov_entry->iov_base;
+ pb->size = iov_entry->iov_len;
+
+ MSO(env->proc).first = (struct erl_off_heap_header*) pb;
+ OH_OVERHEAD(&(MSO(env->proc)), pb->size / sizeof(Eterm));
+
+ erts_refc_inc(&ref_bin->intern.refc, 2);
+ *bin_term = make_binary(pb);
+ } else {
+ ErlHeapBin* hb = (ErlHeapBin*)alloc_heap(env, heap_bin_size(iov_entry->iov_len));
+
+ hb->thing_word = header_heap_bin(iov_entry->iov_len);
+ hb->size = iov_entry->iov_len;
+
+ sys_memcpy(hb->data, iov_entry->iov_base, iov_entry->iov_len);
+ *bin_term = make_binary(hb);
+ }
+
+ return 1;
+}
+
SysIOVec *enif_ioq_peek(ErlNifIOQueue *q, int *iovlen)
{
return erts_ioq_peekq(q, iovlen);
diff --git a/erts/emulator/beam/erl_nif.h b/erts/emulator/beam/erl_nif.h
index 7fb447e4a8..053f7673c4 100644
--- a/erts/emulator/beam/erl_nif.h
+++ b/erts/emulator/beam/erl_nif.h
@@ -52,9 +52,10 @@
** 2.11: 19.0 enif_snprintf
** 2.12: 20.0 add enif_select, enif_open_resource_type_x
** 2.13: 20.1 add enif_ioq
+** 2.14: 21.0 add enif_ioq_peek_head
*/
#define ERL_NIF_MAJOR_VERSION 2
-#define ERL_NIF_MINOR_VERSION 13
+#define ERL_NIF_MINOR_VERSION 14
/*
* The emulator will refuse to load a nif-lib with a major version
diff --git a/erts/emulator/beam/erl_nif_api_funcs.h b/erts/emulator/beam/erl_nif_api_funcs.h
index 9e573307d8..3750fd9b68 100644
--- a/erts/emulator/beam/erl_nif_api_funcs.h
+++ b/erts/emulator/beam/erl_nif_api_funcs.h
@@ -198,6 +198,7 @@ ERL_NIF_API_FUNC_DECL(SysIOVec*,enif_ioq_peek,(ErlNifIOQueue *q, int *iovlen));
ERL_NIF_API_FUNC_DECL(int,enif_inspect_iovec,(ErlNifEnv *env, size_t max_length, ERL_NIF_TERM iovec_term, ERL_NIF_TERM *tail, ErlNifIOVec **iovec));
ERL_NIF_API_FUNC_DECL(void,enif_free_iovec,(ErlNifIOVec *iov));
+ERL_NIF_API_FUNC_DECL(int,enif_ioq_peek_head,(ErlNifEnv *env, ErlNifIOQueue *q, size_t *size, ERL_NIF_TERM *head));
/*
** ADD NEW ENTRIES HERE (before this comment) !!!
@@ -373,6 +374,7 @@ ERL_NIF_API_FUNC_DECL(void,enif_free_iovec,(ErlNifIOVec *iov));
# define enif_ioq_peek ERL_NIF_API_FUNC_MACRO(enif_ioq_peek)
# define enif_inspect_iovec ERL_NIF_API_FUNC_MACRO(enif_inspect_iovec)
# define enif_free_iovec ERL_NIF_API_FUNC_MACRO(enif_free_iovec)
+# define enif_ioq_peek_head ERL_NIF_API_FUNC_MACRO(enif_ioq_peek_head)
/*
** ADD NEW ENTRIES HERE (before this comment)
diff --git a/erts/emulator/test/nif_SUITE.erl b/erts/emulator/test/nif_SUITE.erl
index bec2291867..2afeb7e4cf 100644
--- a/erts/emulator/test/nif_SUITE.erl
+++ b/erts/emulator/test/nif_SUITE.erl
@@ -3037,14 +3037,17 @@ nif_ioq(Config) ->
{enqbraw,a},
{enqbraw,a, 5},
{peek, a},
+ {peek_head, a},
{deq, a, 42},
%% Test enqv
{enqv, a, 2, 100},
+ {peek_head, a},
{deq, a, all},
%% This skips all elements but one in the iolist
{enqv, a, 5, iolist_size(nif_ioq_payload(5)) - 1},
+ {peek_head, a},
{peek, a},
%% Test to enqueue a bunch of refc binaries
@@ -3074,9 +3077,13 @@ nif_ioq(Config) ->
Q = ioq_nif(create),
+ false = ioq_nif(peek_head, Q),
+
{'EXIT', {badarg, _}} = (catch ioq_nif(deq, Q, 1)),
{'EXIT', {badarg, _}} = (catch ioq_nif(enqv, Q, 1, 1234)),
+ false = ioq_nif(peek_head, Q),
+
{'EXIT', {badarg, _}} = (catch ioq_nif(enqv, Q, [atom_in_list], 0)),
{'EXIT', {badarg, _}} = (catch ioq_nif(enqv, Q, [make_ref()], 0)),
{'EXIT', {badarg, _}} = (catch ioq_nif(enqv, Q, [256], 0)),
@@ -3085,6 +3092,8 @@ nif_ioq(Config) ->
{'EXIT', {badarg, _}} = (catch ioq_nif(enqv, Q, [1 bsl 64], 0)),
{'EXIT', {badarg, _}} = (catch ioq_nif(enqv, Q, [{tuple}], 0)),
+ false = ioq_nif(peek_head, Q),
+
{'EXIT', {badarg, _}} = (catch ioq_nif(inspect, [atom_in_list], use_stack)),
{'EXIT', {badarg, _}} = (catch ioq_nif(inspect, [make_ref()], no_stack)),
{'EXIT', {badarg, _}} = (catch ioq_nif(inspect, [256], use_stack)),
@@ -3145,6 +3154,20 @@ nif_ioq_run([{peek, Name} = H|T], State) ->
true = iolist_to_binary(B) == iolist_to_binary(Data),
nif_ioq_run(T, State);
+nif_ioq_run([{peek_head, Name} = H|T], State) ->
+ #{ q := IOQ, b := B } = maps:get(Name, State),
+ RefData = iolist_to_binary(B),
+
+ ct:log("~p", [H]),
+
+ {true, QueueHead} = ioq_nif(peek_head, IOQ),
+ true = byte_size(QueueHead) > 0,
+
+ {RefHead, _Tail} = split_binary(RefData, byte_size(QueueHead)),
+
+ true = QueueHead =:= RefHead,
+
+ nif_ioq_run(T, State);
nif_ioq_run([{deq, Name, all}|T], State) ->
#{ q := IOQ, b := B } = maps:get(Name, State),
Size = ioq_nif(size, IOQ),
diff --git a/erts/emulator/test/nif_SUITE_data/nif_SUITE.c b/erts/emulator/test/nif_SUITE_data/nif_SUITE.c
index 79560a38aa..fa9ae1015c 100644
--- a/erts/emulator/test/nif_SUITE_data/nif_SUITE.c
+++ b/erts/emulator/test/nif_SUITE_data/nif_SUITE.c
@@ -3403,6 +3403,15 @@ static ERL_NIF_TERM ioq(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
return enif_make_badarg(env);
else
return enif_make_atom(env, "true");
+ } else if (enif_is_identical(argv[0], enif_make_atom(env, "peek_head"))) {
+ ERL_NIF_TERM head_term;
+
+ if(enif_ioq_peek_head(env, ioq->q, NULL, &head_term)) {
+ return enif_make_tuple2(env,
+ enif_make_atom(env, "true"), head_term);
+ }
+
+ return enif_make_atom(env, "false");
} else if (enif_is_identical(argv[0], enif_make_atom(env, "peek"))) {
int iovlen, num, i, off = 0;
SysIOVec *iov = enif_ioq_peek(ioq->q, &iovlen);