[tarantool-patches] Re: [PATCH 4/8] netbox: extend codec with 'decode' methods

[Vladislav Shpilevoy]

Hello. Thanks for review! See the diff at the end of letter.
>> diff --git a/src/box/lua/net_box.lua b/src/box/lua/net_box.lua
>> index 4ed2b375d..3868cdf1c 100644
>> --- a/src/box/lua/net_box.lua
>> +++ b/src/box/lua/net_box.lua
>> @@ -50,7 +50,34 @@ local E_PROC_LUA             = box.error.PROC_LUA
>>   
>>   -- utility tables
>>   local is_final_state         = {closed = 1, error = 1}
>> -local method_codec           = {
>> +
>> +local function decode_nil(...) end
> 
>> +local function decode_nothing(...) return ... end
> 
> decode_nop, may be?

Done.

> 
>> +local function decode_one_tuple(response)
>> +    if response[1] then
>> +        return box.tuple.new(response[1])
>> +    end
>> +end
>> +local function decode_single_tuple(response)
>> +    if response[2] then
>> +        return nil, box.error.MORE_THAN_ONE_TUPLE
>> +    end
>> +    if response[1] then
>> +        return box.tuple.new(response[1])
>> +    end
>> +end
> 
> Do we really need this MORE_THAN_ONE_TUPLE error? Can't we use
> decode_one_tuple in 'get' as well? I ask, because having two methods
> called decode_one_tuple and decode_single_tuple is confusing IMO -
> it's unclear what's the difference between them.

I agree with you, it looks ugly, but IProto has no 'get' method, so
we must emulate it via select(limit = 2) + check that a tuple is
only one. I renamed decode_single to decode_unique. Maybe it looks
not so bad.

> 
>> +local function decode_select(response)
>> +    setmetatable(response, sequence_mt)
>> +    for i, v in pairs(response) do
>> +        response[i] = box.tuple.new(v)
>> +    end
>> +    return response
>> +end
>> +local function decode_count(response)
>> +    return response[1]
>> +end
>> +
>> +local method_encoder = {
>>       ping    = internal.encode_ping,
>>       call_16 = internal.encode_call_16,
>>       call_17 = internal.encode_call,
>> @@ -61,6 +88,10 @@ local method_codec           = {
>>       update  = internal.encode_update,
>>       upsert  = internal.encode_upsert,
>>       select  = internal.encode_select,
>> +    get     = internal.encode_select,
>> +    min     = internal.encode_select,
>> +    max     = internal.encode_select,
>> +    count   = internal.encode_call,
>>       -- inject raw data into connection, used by console and tests
>>       inject = function(buf, id, schema_version, bytes)
>>           local ptr = buf:reserve(#bytes)
>> @@ -69,6 +100,24 @@ local method_codec           = {
>>       end
>>   }
>>   
>> +local method_decoder = {
>> +    ping    = decode_nil,
>> +    call_16 = decode_select,
>> +    call_17 = decode_nothing,
>> +    eval    = decode_nothing,
>> +    insert  = decode_one_tuple,
>> +    replace = decode_one_tuple,
>> +    delete  = decode_one_tuple,
>> +    update  = decode_one_tuple,
>> +    upsert  = decode_nil,
>> +    select  = decode_select,
>> +    get     = decode_single_tuple,
>> +    min     = decode_single_tuple,
>> +    max     = decode_single_tuple,
>> +    count   = decode_count,
>> +    inject  = decode_nothing,
>> +}
>> +
>>   local function next_id(id) return band(id + 1, 0x7FFFFFFF) end
>>   
>>   --
> 
>> @@ -1144,9 +1175,8 @@ index_metatable = function(remote)
>>           if opts and opts.buffer then
>>               error("index:min() doesn't support `buffer` argument")
>>           end
>> -        local res = remote:_request('select', opts, self.space.id, self.id,
>> -                                    box.index.GE, 0, 1, key)
>> -        return one_tuple(res)
>> +        return remote:_request('get', opts, self.space.id, self.id,
> 
> Should be 'min'?

Yes, did not notice that. Fixed on the branch.

> 
>> +                               box.index.GE, 0, 1, key)
>>       end
>>   
>>       function methods:max(key, opts)
>> @@ -1154,9 +1184,8 @@ index_metatable = function(remote)
>>           if opts and opts.buffer then
>>               error("index:max() doesn't support `buffer` argument")
>>           end
>> -        local res = remote:_request('select', opts, self.space.id, self.id,
>> -                                    box.index.LE, 0, 1, key)
>> -        return one_tuple(res)
>> +        return remote:_request('get', opts, self.space.id, self.id,
> 
> Should be 'max'?

Same, you are right. Fixed.

See the diff:

diff --git a/src/box/lua/net_box.lua b/src/box/lua/net_box.lua
index 3868cdf1c..53f301356 100644
--- a/src/box/lua/net_box.lua
+++ b/src/box/lua/net_box.lua
@@ -52,13 +52,13 @@ local E_PROC_LUA             = box.error.PROC_LUA
  local is_final_state         = {closed = 1, error = 1}
  
  local function decode_nil(...) end
-local function decode_nothing(...) return ... end
+local function decode_nop(...) return ... end
  local function decode_one_tuple(response)
      if response[1] then
          return box.tuple.new(response[1])
      end
  end
-local function decode_single_tuple(response)
+local function decode_unique_tuple(response)
      if response[2] then
          return nil, box.error.MORE_THAN_ONE_TUPLE
      end
@@ -103,19 +103,19 @@ local method_encoder = {
  local method_decoder = {
      ping    = decode_nil,
      call_16 = decode_select,
-    call_17 = decode_nothing,
-    eval    = decode_nothing,
+    call_17 = decode_nop,
+    eval    = decode_nop,
      insert  = decode_one_tuple,
      replace = decode_one_tuple,
      delete  = decode_one_tuple,
      update  = decode_one_tuple,
      upsert  = decode_nil,
      select  = decode_select,
-    get     = decode_single_tuple,
-    min     = decode_single_tuple,
-    max     = decode_single_tuple,
+    get     = decode_unique_tuple,
+    min     = decode_unique_tuple,
+    max     = decode_unique_tuple,
      count   = decode_count,
-    inject  = decode_nothing,
+    inject  = decode_nop,
  }
  
  local function next_id(id) return band(id + 1, 0x7FFFFFFF) end
@@ -1175,7 +1175,7 @@ index_metatable = function(remote)
          if opts and opts.buffer then
              error("index:min() doesn't support `buffer` argument")
          end
-        return remote:_request('get', opts, self.space.id, self.id,
+        return remote:_request('min', opts, self.space.id, self.id,
                                 box.index.GE, 0, 1, key)
      end
  
@@ -1184,7 +1184,7 @@ index_metatable = function(remote)
          if opts and opts.buffer then
              error("index:max() doesn't support `buffer` argument")
          end
-        return remote:_request('get', opts, self.space.id, self.id,
+        return remote:_request('max', opts, self.space.id, self.id,
                                 box.index.LE, 0, 1, key)
      end