| commit | 6b0ff74ecf63e26c7315f6745de36aff66deb59d | [log] [tgz] |
|---|---|---|
| author | Jon Skeet <jonskeet@google.com> | Tue May 05 06:53:00 2020 +0100 |
| committer | Jon Skeet <skeet@pobox.com> | Fri May 08 06:17:50 2020 +0100 |
| tree | 94b63a178a28ee1de426a19fa6510a23f3431b9f | |
| parent | cac7136436a9bb9503627376414a0a808f8ed4f0 [diff] |
Implement HasPresence for C# FieldDescriptor.HasPresence returns true if both ClearValue and HasValue (on the accessor) can be expected to work. Some fields have a working ClearValue, but no HasValue; HasPresence returns false for those fields. Generally: - Extension fields have presence if and only if they're singular - Repeated fields do not support presence - Map fields do not support presence - Message fields support presence - Oneof fields support presence (this includes synthetic oneof fields, so that covers proto3 optional singular fields) - Proto2 singular primitive fields support presence - Proto3 singular primitive fields do not support presence (unless they're in a oneof, covered above)
Copyright 2008 Google Inc.
https://developers.google.com/protocol-buffers/
Protocol Buffers (a.k.a., protobuf) are Google's language-neutral, platform-neutral, extensible mechanism for serializing structured data. You can find protobuf's documentation on the Google Developers site.
This README file contains protobuf installation instructions. To install protobuf, you need to install the protocol compiler (used to compile .proto files) and the protobuf runtime for your chosen programming language.
The protocol compiler is written in C++. If you are using C++, please follow the C++ Installation Instructions to install protoc along with the C++ runtime.
For non-C++ users, the simplest way to install the protocol compiler is to download a pre-built binary from our release page:
https://github.com/protocolbuffers/protobuf/releases
In the downloads section of each release, you can find pre-built binaries in zip packages: protoc-$VERSION-$PLATFORM.zip. It contains the protoc binary as well as a set of standard .proto files distributed along with protobuf.
If you are looking for an old version that is not available in the release page, check out the maven repo here:
https://repo1.maven.org/maven2/com/google/protobuf/protoc/
These pre-built binaries are only provided for released versions. If you want to use the github master version at HEAD, or you need to modify protobuf code, or you are using C++, it's recommended to build your own protoc binary from source.
If you would like to build protoc binary from source, see the C++ Installation Instructions.
Protobuf supports several different programming languages. For each programming language, you can find instructions in the corresponding source directory about how to install protobuf runtime for that specific language:
| Language | Source | Ubuntu | MacOS | Windows |
|---|---|---|---|---|
| C++ (include C++ runtime and protoc) | src |    |   | |
| Java | java |     | ||
| Python | python |           |    |  |
| Objective-C | objectivec |     | ||
| C# | csharp |  |  | |
| JavaScript | js |  |  | |
| Ruby | ruby |      |      | |
| Go | golang/protobuf | |||
| PHP | php |   |   | |
| Dart | dart-lang/protobuf |  |
The best way to learn how to use protobuf is to follow the tutorials in our developer guide:
https://developers.google.com/protocol-buffers/docs/tutorials
If you want to learn from code examples, take a look at the examples in the examples directory.
The complete documentation for Protocol Buffers is available via the web at: