Return the size of the field read from the validator, permitting us to
avoid an extra parse when skipping over groups.
Return an UnmarshalOutput from the validator, since it already combines
two of the validator outputs: bytes read and initialization status.
Remove initialization status from the ValidationStatus enum, since it's
covered by the UnmarshalOutput.
Change-Id: I3e684c45d15aa1992d8dc3bde0f608880d34a94b
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/217763
Reviewed-by: Joe Tsai <joetsai@google.com>
This adds a experimental function to the internal/impl package which
validates a wire-format message against a message type. The validator
reports whether the message can be successfully unmarshaled, and whether
the result is initialized (all required fields are set). In some cases,
the validator returns ambiguous results when full validation would be
expensive.
The validator is unused outside of tests. In the future, it may be used
to permit lazy unmarshaling of some data. It is being added now for
testing; in particular, the wire fuzzer now checks the validator output
for consistency with the unmarshaler.
The validator adds a small amount of unused per-MessageType state. If
this becomes a concern, we could conditionalize it with a build tag.
Change-Id: I4216ef81d6a9ed975302eed189b02d08608858b4
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/212302
Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>
