A Duration represents a signed, fixed-length span of time represented
as a count of seconds and fractions of seconds at nanosecond
resolution. It is independent of any calendar and concepts like “day”
or “month”. It is related to Timestamp in that the difference between
two Timestamp values is a Duration and it can be added or subtracted
from a Timestamp. Range is approximately +-10,000 years.
A generic empty message that you can re-use to avoid defining duplicated
empty messages in your APIs. A typical example is to use it as the request
or the response type of an API method. For instance:
TODO Enums in C++ gencode (and potentially other languages) are
not well scoped. This means that each of the feature enums below can clash
with each other. The short names we’ve chosen maximize call-site
readability, but leave us very open to this scenario. A future feature will
be designed and implemented to handle this, hopefully before we ever hit a
conflict here.
A compiled specification for the defaults of a set of features. These
messages are generated from FeatureSet extensions and can be used to seed
feature resolution. The resolution with this object becomes a simple search
for the closest matching edition, followed by proto merges.
Describes the relationship between generated code and its original source
file. A GeneratedCodeInfo message is associated with only one generated
source file, but may contain references to different source .proto files.
A Timestamp represents a point in time independent of any time zone or local
calendar, encoded as a count of seconds and fractions of seconds at
nanosecond resolution. The count is relative to an epoch at UTC midnight on
January 1, 1970, in the proleptic Gregorian calendar which extends the
Gregorian calendar backwards to year one.
A message representing a option the parser does not recognize. This only
appears in options protos created by the compiler::Parser class.
DescriptorPool resolves these when building Descriptor objects. Therefore,
options protos in descriptor objects (e.g. returned by Descriptor::options(),
or produced by Descriptor::CopyTo()) will never have UninterpretedOptions
in them.
Describes the ‘visibility’ of a symbol with respect to the proto import
system. Symbols can only be imported when the visibility rules do not prevent
it (ex: local symbols cannot be imported). Visibility modifiers can only set
on message and enum as they are the only types available to be referenced
from other files.