tree fb1d3254e572ecc5368ee61aaf9a27c526cf4583
parent f0831e87e2b78faccf88fb0c491d37a3ef7467f1
author Damien Neil <dneil@google.com> 1579717696 -0800
committer Damien Neil <dneil@google.com> 1579726337 +0000

proto: add MarshalState, UnmarshalState

Add functions to the proto package which plumb through the fast-path state.

As a sample use case: A followup CL adds an Initialized field to
protoiface.UnmarshalOutput, permitting the unmarshaller to report back
when it can confirm that a message is fully initialized. We want to
preserve that information when an unmarshal operation threads through
the proto package (such as when unmarshaling extensions).

To allow these functions to be added as methods of MarshalOptions and
UnmarshalOptions rather than top-level functions, separate the options
from the input structs.

Also update options passed to fast-path methods to set AllowPartial and
Merge to reflect the expected behavior of those methods. (Always allow
partial, never merge.)

Change-Id: I482477b0c9340793be533e75a86d0bb88708716a
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/215877
Reviewed-by: Joe Tsai <joetsai@google.com>