[Tarantool-patches] [PATCH 1.10 05/16] WIP: module api/lua: add luaL_iscdata() function
Alexander Turenko
alexander.turenko at tarantool.org
Wed Sep 23 04:40:18 MSK 2020
It is useful to provide a module specific error when cdata expected, but
a value of another type is passed.
Alternative would be using of lua_type() to check against LUA_TCDATA,
but this constant is not exposed for modules. See more in the
luaL_iscdata() API comment.
XXX: Add a test to test/app-tap/module_api.{c,test.lua}.
Part of #5273
(cherry picked from commit 98551e8b90ebd2839dee57fee13f446aee515e42)
---
extra/exports | 1 +
src/lua/utils.c | 6 ++++++
src/lua/utils.h | 20 ++++++++++++++++++++
3 files changed, 27 insertions(+)
diff --git a/extra/exports b/extra/exports
index 52bb29d68..a7d8ef81b 100644
--- a/extra/exports
+++ b/extra/exports
@@ -117,6 +117,7 @@ coio_close
coio_call
coio_getaddrinfo
luaL_pushcdata
+luaL_iscdata
luaL_checkcdata
luaL_setcdatagc
luaL_ctypeid
diff --git a/src/lua/utils.c b/src/lua/utils.c
index d88efc560..e555607cf 100644
--- a/src/lua/utils.c
+++ b/src/lua/utils.c
@@ -102,6 +102,12 @@ luaL_pushcdata(struct lua_State *L, uint32_t ctypeid)
return cdataptr(cd);
}
+int
+luaL_iscdata(struct lua_State *L, int idx)
+{
+ return lua_type(L, idx) == LUA_TCDATA;
+}
+
void *
luaL_checkcdata(struct lua_State *L, int idx, uint32_t *ctypeid)
{
diff --git a/src/lua/utils.h b/src/lua/utils.h
index 5164eb5bf..fe6728986 100644
--- a/src/lua/utils.h
+++ b/src/lua/utils.h
@@ -69,6 +69,26 @@ extern struct ibuf *tarantool_lua_ibuf;
/** \cond public */
+/**
+ * @brief Checks whether a value on the Lua stack is a cdata.
+ *
+ * Unlike <luaL_checkcdata>() this function does not raise an
+ * error. It is useful to raise a domain specific error.
+ *
+ * Lua API and module API don't expose LUA_TCDATA constant.
+ * We have no guarantee that this constant will remain the same in
+ * future LuaJIT versions. So this function should be used in
+ * modules instead of `lua_type(L, idx) == LUA_TCDATA`.
+ *
+ * @param L Lua State
+ * @param idx stack index
+ *
+ * @return 1 if the value at the given acceptable index is a cdata
+ * and 0 otherwise.
+ */
+LUA_API int
+luaL_iscdata(struct lua_State *L, int idx);
+
/**
* @brief Push cdata of given \a ctypeid onto the stack.
* CTypeID must be used from FFI at least once. Allocated memory returned
--
2.25.0
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