[Tarantool-patches] [PATCH 1/1] box: export box_session_push to the public C API

[Vladislav Shpilevoy <v.shpilevoy@tarantool.org>]

It was a customer request. Nothing special here, the patch is
trivial, with a couple of short notes:

1) Sync argument was removed. It will disappear from Lua API as
  well, according to #4689. Port is replaced with raw MessagePack,
  because port is not a part of public API. Session is omitted as
  well. Indeed, a user can't push to a foreign session, and the
  current session can be obtained inside box_session_push(). And
  anyway session is not in the public C API.

2) Dump is done using obuf_dup(), just like tuple_to_obuf() does.
  obuf_alloc() would be a bad call here, because it wouldn't be
  able to split the pushed data into several obuf chunks, and
  would cause obuf fragmentation.

Closes #4734
---
Issue: https://github.com/tarantool/tarantool/issues/4734
Branch: https://github.com/tarantool/tarantool/tree/gerold103/gh-4734-export-box-session-push

 extra/exports               |  1 +
 src/box/box.cc              | 12 +++++++++++
 src/box/box.h               | 14 +++++++++++++
 src/box/call.c              | 14 ++++++++++++-
 test/box/function1.c        |  7 +++++++
 test/box/function1.result   | 41 +++++++++++++++++++++++++++++++++++++
 test/box/function1.test.lua | 19 +++++++++++++++++
 7 files changed, 107 insertions(+), 1 deletion(-)

diff --git a/extra/exports b/extra/exports
index 7b84a1452..bc3759244 100644
--- a/extra/exports
+++ b/extra/exports
@@ -216,6 +216,7 @@ box_truncate
 box_sequence_next
 box_sequence_set
 box_sequence_reset
+box_session_push
 box_index_iterator
 box_iterator_next
 box_iterator_free
diff --git a/src/box/box.cc b/src/box/box.cc
index 1b2b27d61..9935c164c 100644
--- a/src/box/box.cc
+++ b/src/box/box.cc
@@ -1433,6 +1433,18 @@ box_sequence_reset(uint32_t seq_id)
 	return sequence_data_delete(seq_id);
 }
 
+int
+box_session_push(const char *data, const char *data_end)
+{
+	struct session *session = current_session();
+	if (session == NULL)
+		return -1;
+	struct port_msgpack port;
+	struct port *base = (struct port *) &port;
+	port_msgpack_create(base, data, data_end - data);
+	return session_push(session, session_sync(session), base);
+}
+
 static inline void
 box_register_replica(uint32_t id, const struct tt_uuid *uuid)
 {
diff --git a/src/box/box.h b/src/box/box.h
index a212e6510..93773cedd 100644
--- a/src/box/box.h
+++ b/src/box/box.h
@@ -442,6 +442,20 @@ box_sequence_set(uint32_t seq_id, int64_t value);
 API_EXPORT int
 box_sequence_reset(uint32_t seq_id);
 
+/**
+ * Push MessagePack data into a session data channel - socket,
+ * console or whatever is behind the session. Note, that
+ * successful push does not guarantee delivery in case it was sent
+ * into the network. Just like with write()/send() system calls.
+ *
+ * \param data begin of MessagePack to push
+ * \param data_end end of MessagePack to push
+ * \retval -1 on error (check box_error_last())
+ * \retval 0 on success
+ */
+API_EXPORT int
+box_session_push(const char *data, const char *data_end);
+
 /** \endcond public */
 
 /**
diff --git a/src/box/call.c b/src/box/call.c
index bcaa453ea..336044a3b 100644
--- a/src/box/call.c
+++ b/src/box/call.c
@@ -64,11 +64,23 @@ port_msgpack_get_msgpack(struct port *base, uint32_t *size)
 	return port->data;
 }
 
+static int
+port_msgpack_dump_msgpack(struct port *base, struct obuf *out)
+{
+	struct port_msgpack *port = (struct port_msgpack *) base;
+	assert(port->vtab == &port_msgpack_vtab);
+	size_t size = port->data_sz;
+	if (obuf_dup(out, port->data, size) == size)
+		return 0;
+	diag_set(OutOfMemory, size, "obuf_dup", "port->data");
+	return -1;
+}
+
 extern void
 port_msgpack_dump_lua(struct port *base, struct lua_State *L, bool is_flat);
 
 static const struct port_vtab port_msgpack_vtab = {
-	.dump_msgpack = NULL,
+	.dump_msgpack = port_msgpack_dump_msgpack,
 	.dump_msgpack_16 = NULL,
 	.dump_lua = port_msgpack_dump_lua,
 	.dump_plain = NULL,
diff --git a/test/box/function1.c b/test/box/function1.c
index 87062d6a8..b2ce752a9 100644
--- a/test/box/function1.c
+++ b/test/box/function1.c
@@ -245,3 +245,10 @@ test_sleep(box_function_ctx_t *ctx, const char *args, const char *args_end)
 		fiber_sleep(0);
 	return 0;
 }
+
+int
+test_push(box_function_ctx_t *ctx, const char *args, const char *args_end)
+{
+	(void) ctx;
+	return box_session_push(args, args_end);
+}
diff --git a/test/box/function1.result b/test/box/function1.result
index b91d63c51..a57de403a 100644
--- a/test/box/function1.result
+++ b/test/box/function1.result
@@ -1065,3 +1065,44 @@ box.func['test'].is_multikey == true
 box.func['test']:drop()
 ---
 ...
+--
+-- gh-4734: C API for session push.
+--
+build_path = os.getenv("BUILDDIR")
+---
+...
+package.cpath = build_path..'/test/box/?.so;'..build_path..'/test/box/?.dylib;'..package.cpath
+---
+...
+box.schema.func.create('function1.test_push', {language = 'C'})
+---
+...
+box.schema.user.grant('guest', 'super')
+---
+...
+c = net.connect(box.cfg.listen)
+---
+...
+messages = {}
+---
+...
+c:call('function1.test_push',	\
+       {1, 2, 3},		\
+       {on_push = table.insert,	\
+        on_push_ctx = messages})
+---
+- []
+...
+messages
+---
+- - [1, 2, 3]
+...
+c:close()
+---
+...
+box.schema.user.revoke('guest', 'super')
+---
+...
+box.schema.func.drop('function1.test_push')
+---
+...
diff --git a/test/box/function1.test.lua b/test/box/function1.test.lua
index b1841f3ad..4f2c1ea2d 100644
--- a/test/box/function1.test.lua
+++ b/test/box/function1.test.lua
@@ -380,3 +380,22 @@ box.schema.func.drop("SUM")
 box.schema.func.create('test', {body = "function(tuple) return tuple end", is_deterministic = true, opts = {is_multikey = true}})
 box.func['test'].is_multikey == true
 box.func['test']:drop()
+
+--
+-- gh-4734: C API for session push.
+--
+build_path = os.getenv("BUILDDIR")
+package.cpath = build_path..'/test/box/?.so;'..build_path..'/test/box/?.dylib;'..package.cpath
+
+box.schema.func.create('function1.test_push', {language = 'C'})
+box.schema.user.grant('guest', 'super')
+c = net.connect(box.cfg.listen)
+messages = {}
+c:call('function1.test_push',	\
+       {1, 2, 3},		\
+       {on_push = table.insert,	\
+        on_push_ctx = messages})
+messages
+c:close()
+box.schema.user.revoke('guest', 'super')
+box.schema.func.drop('function1.test_push')
-- 
2.21.1 (Apple Git-122.3)