1) You misunderstood the enum definition in proto. field1, field2 and
field3 don't define fields on message A and B. Instead, they define the
enum value of enum foo.
2) If the nested message field have the same structure and same field
number, it will still work.
BTW, I just find your proto definition is not valid. Please take a look of
the example, see how a valid proto looks like.
On Wed, Apr 4, 2018 at 9:46 AM Shyam S R <sr.sh...@gmail.com> wrote:
> By source values i meant the values of enums in "in" message: void copy(A
> &in, B &out). The enum values in A and B differ by one element.
>
> By nested messages,
> message A {
> enum foo {
> field1 = 0;
> field2 = 1;
> }
> int32 id;
> string name;
> foo type;
> NestedMsg1 msg1;
> }
>
> message NestedMsg1 {
> int32 id;
> string name;
> }
>
> If message B were to also have a similar structure, will
> out.ParseFromString(in.SerializeToString()) take care of nested messages as
> well ?
>
> I also explore CopyFrom(Message&) but not sure if it will work-
>
> Thanks,
> Shyam
>
> On Wednesday, April 4, 2018 at 9:37:38 AM UTC-7, Bo Yang wrote:
>
>> I don't quite follow your question.
>> What's the source values and nested messages you are referring to ?
>>
>> On Tue, Apr 3, 2018 at 5:52 PM Shyam S R <sr.s...@gmail.com> wrote:
>>
>>> thanks for the reply @Bo. Follow up: What happens to the enums, the
>>> source values are maintained i suppose ?
>>>
>>> Does it work with nested messages also, in the sense, does
>>> ParseFromString look for any message type information within the stream or
>>> as long as the scalar types are good it parses ok ?
>>>
>>> On Tuesday, April 3, 2018 at 5:42:26 PM UTC-7, Bo Yang wrote:
>>>
>>>> The second copy looks correct to me.
>>>>
>>>> On Tue, Apr 3, 2018 at 5:26 PM Shyam S R <sr.s...@gmail.com> wrote:
>>>>
>>> Hi all,
>>>>>
>>>>> Is there a favored way to copy a protobuf message from one type to
>>>>> another ? A little background:
>>>>>
>>>>> I have two messages for example:
>>>>> message A {
>>>>> enum foo {
>>>>> field1 = 0;
>>>>> field2 = 1;
>>>>> }
>>>>> int32 id;
>>>>> string name;
>>>>> foo type;
>>>>> }
>>>>>
>>>>> message B {
>>>>> enum foo {
>>>>> field1 = 0;
>>>>> field2 = 1;
>>>>> field3 =2;
>>>>> }
>>>>> int32 id;
>>>>> string name;
>>>>> foo type;
>>>>> }
>>>>>
>>>>> I have references to these messages and want to implement this method:
>>>>> void copy(A &in, B &out) {
>>>>> // in's contents need to be copied to out
>>>>> }
>>>>>
>>>>> the only difference between A and B is the enum field and they are
>>>>> named different. There could be more messages within the message types A
>>>>> and B with the same fields, but only enum's having an extra field in B.
>>>>> How
>>>>> should i go about this ?
>>>>>
>>>>> Do the following options look feasible :
>>>>> void copy(A &in, B &out) {
>>>>> // in's contents need to be copied to out
>>>>> cast in to type B
>>>>> out = in;
>>>>> }
>>>>>
>>>>> void copy(A &in, B &out) {
>>>>> // in's contents need to be copied to out
>>>>> Use in.SerializeAsString() and pipe it to out.ParseFromString()
>>>>> }
>>>>>
>>>>> Appreciate the community's help!
>>>>>
>>>>> Thanks!
>>>>>
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