Now , I wrote like this.
message head
{
requirement int command = 1;
requeirment string mask = 2;
... and so on.
optional bytes module = 10;
}
All these module PB objects SerializeToString() into head_instance's
module column.
It is ok , between C++ and Python.
SuKai 写道:
> I want to define my protocol with PB.
>
> So, first I define the protocol head.
> message head
> {
> requirement int command = 1;
> requeirment string mask = 2;
> ... and so on.
> optional Module_A ma = 10;
> optional Module_B mb = 11;
> ... and so on.
> }
>
> message Module_A
> {
> ...
> }
>
> message Module_B
> {
> ...
> }
>
> All these modules are increasing.
>
> I want to construct this protocol with PB .
>
> Initial, I think fill these modules PB objects into head_instance's
> colum(this is a string type).
>
> Kenton Varda 写道:
>> I don't quite understand your question. It's safe to add new fields
>> to a protocol buffer.
>>
>> If you want to store all the values as one unit -- for instance, so
>> that old releases that don't know about new fields still know that
>> the fields represent the same "column" -- you could always wrap them
>> in another message like:
>>
>> message A {
>> required UserUnion user = 1;
>> }
>>
>> message UserUnion {
>> optional B b = 1;
>> optional C c = 2;
>> optional D d = 3;
>> }
>>
>> Code which just passes around UserUnion objects without looking
>> inside will work even if
>> On Wed, Oct 21, 2009 at 6:19 PM, SuKai <sukai090...@gmail.com
>> <mailto:sukai090...@gmail.com>> wrote:
>>
>> I release this proto at R1:
>>
>> message A {
>> optional B user_b = 1;
>> optional C user_c = 2;
>> optional D user_d = 3;
>> }
>>
>> but if I find some fault with this proto or extend this proto at R2:
>>
>> message A {
>> optional B user_b = 1;
>> optional C user_c = 2;
>> optional E user_d = 3;
>> optional F user_e = 4;
>> }
>>
>> So , I want use R1's proto instance to encode this message on R2'
>> proto instance.
>> Can I get the true value for the same colums (user_b & user_c)
>> value?
>>
>> Thanks.
>>
>>
>> Kenton Varda 写道:
>>
>> On Wed, Oct 21, 2009 at 6:04 PM, SuKai <sukai090...@gmail.com
>> <mailto:sukai090...@gmail.com> <mailto:sukai090...@gmail.com
>> <mailto:sukai090...@gmail.com>>> wrote:
>>
>> Because A_instance.user stored with different type of PB.
>>
>> Fill A_instance.user with B, C, or D , these are diff PB
>> objects.
>>
>>
>> Then you should have three different fields:
>>
>> message A {
>> optional B user_b = 1;
>> optional C user_c = 2;
>> optional D user_d = 3;
>> }
>>
>>
>
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