[Tarantool-patches] [PATCH v2 2/3] box: introduce box_return_mp() public C function
Vladislav Shpilevoy
v.shpilevoy at tarantool.org
Thu Apr 23 03:12:40 MSK 2020
Closes #4641
@TarantoolBot document
Title: box_return_mp() public C function
Stored C functions could return a result only via
`box_return_tuple()` function. That made users create a tuple
every time they wanted to return something from a C function.
Now public C API offers another way to return - `box_return_mp()`.
It allows to return arbitrary MessagePack, not wrapped into a
tuple object. This is simpler to use for small results like a
number, boolean, or a short string. Besides, `box_return_mp()` is
much faster than `box_return_tuple()`, especially for small
MessagePack.
Note, that it is faster only if an alternative is to create a
tuple by yourself. If an already existing tuple was obtained from
an iterator, and you want to return it, then of course it is
faster to return via `box_return_tuple()`, than via extraction of
tuple data, and calling `box_return_mp()`.
Here is the function declaration from module.h:
```C
/**
* Return MessagePack from a stored C procedure. The MessagePack
* is copied, so it is safe to free/reuse the passed arguments
* after the call.
* MessagePack is not validated, for the sake of speed. It is
* expected to be a single encoded object. An attempt to encode
* and return multiple objects without wrapping them into an
* MP_ARRAY or MP_MAP is undefined behaviour.
*
* \param ctx An opaque structure passed to the stored C procedure
* by Tarantool.
* \param mp Begin of MessagePack.
* \param mp_end End of MessagePack.
* \retval -1 Error.
* \retval 0 Success.
*/
API_EXPORT int
box_return_mp(box_function_ctx_t *ctx, const char *mp, const char *mp_end);
```
---
extra/exports | 1 +
src/box/box.cc | 6 ++++++
src/box/box.h | 19 +++++++++++++++++++
test/box/function1.c | 37 +++++++++++++++++++++++++++++++++++++
test/box/function1.result | 33 +++++++++++++++++++++++++++++++++
test/box/function1.test.lua | 16 ++++++++++++++++
6 files changed, 112 insertions(+)
diff --git a/extra/exports b/extra/exports
index d6b02e714..ec80a78a1 100644
--- a/extra/exports
+++ b/extra/exports
@@ -210,6 +210,7 @@ box_tuple_extract_key
box_tuple_compare
box_tuple_compare_with_key
box_return_tuple
+box_return_mp
box_space_id_by_name
box_index_id_by_name
box_select
diff --git a/src/box/box.cc b/src/box/box.cc
index 12f3a50a7..9fd10d64c 100644
--- a/src/box/box.cc
+++ b/src/box/box.cc
@@ -1075,6 +1075,12 @@ box_return_tuple(box_function_ctx_t *ctx, box_tuple_t *tuple)
return port_c_add_tuple(ctx->port, tuple);
}
+int
+box_return_mp(box_function_ctx_t *ctx, const char *mp, const char *mp_end)
+{
+ return port_c_add_mp(ctx->port, mp, mp_end);
+}
+
/* schema_find_id()-like method using only public API */
uint32_t
box_space_id_by_name(const char *name, uint32_t len)
diff --git a/src/box/box.h b/src/box/box.h
index c94e500ab..557542a83 100644
--- a/src/box/box.h
+++ b/src/box/box.h
@@ -284,6 +284,25 @@ typedef struct box_function_ctx box_function_ctx_t;
API_EXPORT int
box_return_tuple(box_function_ctx_t *ctx, box_tuple_t *tuple);
+/**
+ * Return MessagePack from a stored C procedure. The MessagePack
+ * is copied, so it is safe to free/reuse the passed arguments
+ * after the call.
+ * MessagePack is not validated, for the sake of speed. It is
+ * expected to be a single encoded object. An attempt to encode
+ * and return multiple objects without wrapping them into an
+ * MP_ARRAY or MP_MAP is undefined behaviour.
+ *
+ * \param ctx An opaque structure passed to the stored C procedure
+ * by Tarantool.
+ * \param mp Begin of MessagePack.
+ * \param mp_end End of MessagePack.
+ * \retval -1 Error.
+ * \retval 0 Success.
+ */
+API_EXPORT int
+box_return_mp(box_function_ctx_t *ctx, const char *mp, const char *mp_end);
+
/**
* Find space id by name.
*
diff --git a/test/box/function1.c b/test/box/function1.c
index a28431e86..84bbdd710 100644
--- a/test/box/function1.c
+++ b/test/box/function1.c
@@ -252,3 +252,40 @@ test_push(box_function_ctx_t *ctx, const char *args, const char *args_end)
(void)ctx;
return box_session_push(args, args_end);
}
+
+int
+test_return_mp(box_function_ctx_t *ctx, const char *args, const char *args_end)
+{
+ (void) args;
+ (void) args_end;
+ char buf[512];
+ char *pos = mp_encode_uint(buf, 1);
+ int rc = box_return_mp(ctx, buf, pos);
+ if (rc != 0)
+ return rc;
+
+ pos = mp_encode_int(buf, -1);
+ rc = box_return_mp(ctx, buf, pos);
+ if (rc != 0)
+ return rc;
+
+ pos = mp_encode_uint(buf, UINT64_MAX);
+ rc = box_return_mp(ctx, buf, pos);
+ if (rc != 0)
+ return rc;
+
+ const char *str = "123456789101112131415";
+ pos = mp_encode_str(buf, str, strlen(str));
+ rc = box_return_mp(ctx, buf, pos);
+ if (rc != 0)
+ return rc;
+
+ pos = mp_encode_array(buf, 1);
+ pos = mp_encode_uint(pos, 2);
+ box_tuple_t *tuple = box_tuple_new(box_tuple_format_default(),
+ buf, pos);
+ if (tuple == NULL)
+ return -1;
+ rc = box_return_tuple(ctx, tuple);
+ return rc;
+}
diff --git a/test/box/function1.result b/test/box/function1.result
index b91d63c51..905a4cdab 100644
--- a/test/box/function1.result
+++ b/test/box/function1.result
@@ -791,6 +791,39 @@ box.schema.func.drop("function1.multireturn")
---
...
--
+-- gh-4641: box_return_mp() C API to return arbitrary MessagePack
+-- from C functions.
+--
+name = 'function1.test_return_mp'
+---
+...
+box.schema.func.create(name, {language = "C", exports = {'LUA'}})
+---
+...
+box.func[name]:call()
+---
+- 1
+- -1
+- 18446744073709551615
+- '123456789101112131415'
+- [2]
+...
+box.schema.user.grant('guest', 'super')
+---
+...
+-- Netbox:call() returns not the same as local call for C
+-- functions, see #4799.
+net:connect(box.cfg.listen):call(name)
+---
+- [1, -1, 18446744073709551615, '123456789101112131415', [2]]
+...
+box.schema.user.revoke('guest', 'super')
+---
+...
+box.schema.func.drop(name)
+---
+...
+--
-- gh-4182: Introduce persistent Lua functions.
--
test_run:cmd("setopt delimiter ';'")
diff --git a/test/box/function1.test.lua b/test/box/function1.test.lua
index b1841f3ad..ab7b586a0 100644
--- a/test/box/function1.test.lua
+++ b/test/box/function1.test.lua
@@ -268,6 +268,22 @@ box.schema.func.create('function1.multireturn', {language = "C", exports = {'LUA
box.execute("SELECT \"function1.multireturn\"()")
box.schema.func.drop("function1.multireturn")
+--
+-- gh-4641: box_return_mp() C API to return arbitrary MessagePack
+-- from C functions.
+--
+name = 'function1.test_return_mp'
+box.schema.func.create(name, {language = "C", exports = {'LUA'}})
+box.func[name]:call()
+
+box.schema.user.grant('guest', 'super')
+-- Netbox:call() returns not the same as local call for C
+-- functions, see #4799.
+net:connect(box.cfg.listen):call(name)
+box.schema.user.revoke('guest', 'super')
+
+box.schema.func.drop(name)
+
--
-- gh-4182: Introduce persistent Lua functions.
--
--
2.21.1 (Apple Git-122.3)
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