[Tarantool-patches] [PATCH vshard 02/11] storage: add helper for local functions invocation

[Vladislav Shpilevoy]

Function local_call() works like netbox.self.call, but is
exception-safe, and uses cached values of 'netbox.self' and
'netbox.self.call'. This saves at least 3 indexing operations,
which are not free as it appeared.

The cached values are not used directly in storage_call(), because
local_call() also will be used from the future function
storage_map() - a part of map-reduce API.

Needed for #147
---
 vshard/storage/init.lua | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/vshard/storage/init.lua b/vshard/storage/init.lua
index e0ce31d..a3d383d 100644
--- a/vshard/storage/init.lua
+++ b/vshard/storage/init.lua
@@ -6,6 +6,8 @@ local trigger = require('internal.trigger')
 local ffi = require('ffi')
 local yaml_encode = require('yaml').encode
 local fiber_clock = lfiber.clock
+local netbox_self = netbox.self
+local netbox_self_call = netbox_self.call
 
 local MODULE_INTERNALS = '__module_vshard_storage'
 -- Reload requirements, in case this module is reloaded manually.
@@ -171,6 +173,16 @@ else
     bucket_ref_new = ffi.typeof("struct bucket_ref")
 end
 
+--
+-- Invoke a function on this instance. Arguments are unpacked into the function
+-- as arguments.
+-- The function returns pcall() as is, because is used from places where
+-- exceptions are not allowed.
+--
+local function local_call(func_name, args)
+    return pcall(netbox_self_call, netbox_self, func_name, args)
+end
+
 --
 -- Trigger for on replace into _bucket to update its generation.
 --
@@ -2275,7 +2287,7 @@ local function storage_call(bucket_id, mode, name, args)
     if not ok then
         return ok, err
     end
-    ok, ret1, ret2, ret3 = pcall(netbox.self.call, netbox.self, name, args)
+    ok, ret1, ret2, ret3 = local_call(name, args)
     _, err = bucket_unref(bucket_id, mode)
     assert(not err)
     if not ok then
-- 
2.24.3 (Apple Git-128)