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flutter / third_party / protobuf / 4e6b93ca4e315c177fcdd56a723445fa5a5a8749
commit4e6b93ca4e315c177fcdd56a723445fa5a5a8749[log] [tgz]
authorMark Hansen <markhansen@google.com>Mon Aug 12 07:09:56 2024 -0700
committerCopybara-Service <copybara-worker@google.com>Mon Aug 12 07:15:12 2024 -0700
tree10b74086f27aafbeeca192d6ed672b5bf748c4ff
parent744c9ddfc5d652b9e646474fef3751bee15fae1a [diff]
Remove a volatile read/write in SmallSortedMap.entrySet()

I don't know why this was volatile.

Volatile semantics are not strong enough for making this read-then-write a
transaction. You'd need a mutex or AtomicReference to achieve that.

Maybe it's so that if someone else has already made a EntrySet on another
thread, we can reuse that? But, it's probably cheaper to make a new EntrySet
probably than to do the volatile read-or-write (this is just a guess, may be wrong, I'm
not super experienced with the cost of volatiles).

The EntrySet is stateless (except for the state of its containing
SmallSortedMap) so it's fine to have more than one of them.

The commit introducing this doesn't explain why it's volatile, but the method
comment referring to "Similar to the AbstractMap implementation of {@code
keySet()}" may have some clues.

AbstractMap.keySet uses a transient keySet, not a volatile keySet.

Is it possible that this initial implementation mistook transient for volatile?

Anyway, it's unnecessary, let's rip it out and enjoy a little more performance.

PiperOrigin-RevId: 662071950
1 file changed
tree: 10b74086f27aafbeeca192d6ed672b5bf748c4ff
  1. .bcr/
  2. .github/
  3. bazel/
  4. benchmarks/
  5. build_defs/
  6. ci/
  7. cmake/
  8. compatibility/
  9. conformance/
  10. csharp/
  11. docs/
  12. editions/
  13. editors/
  14. examples/
  15. google3/
  16. hpb/
  17. hpb_generator/
  18. java/
  19. lua/
  20. objectivec/
  21. php/
  22. pkg/
  23. protos/
  24. python/
  25. ruby/
  26. rust/
  27. src/
  28. third_party/
  29. toolchain/
  30. upb/
  31. upb_generator/
  32. .bazelignore
  33. .bazelrc
  34. .clang-format
  35. .gitignore
  36. .gitmodules
  37. .readthedocs.yml
  38. appveyor.bat
  39. appveyor.yml
  40. BUILD.bazel
  41. Cargo.bazel.lock
  42. Cargo.lock
  43. CMakeLists.txt
  44. CODE_OF_CONDUCT.md
  45. CONTRIBUTING.md
  46. CONTRIBUTORS.txt
  47. fix_permissions.sh
  48. generate_descriptor_proto.sh
  49. global.json
  50. google3_export_generated_files.sh
  51. LICENSE
  52. maven_install.json
  53. MODULE.bazel
  54. PrivacyInfo.xcprivacy
  55. Protobuf-C++.podspec
  56. protobuf.bzl
  57. Protobuf.podspec
  58. protobuf_deps.bzl
  59. protobuf_release.bzl
  60. protobuf_version.bzl
  61. README.md
  62. regenerate_stale_files.sh
  63. SECURITY.md
  64. version.json
  65. WORKSPACE
  66. WORKSPACE.bzlmod
README.md

Protocol Buffers - Google's data interchange format

OpenSSF Scorecard

Copyright 2023 Google LLC

Overview

Protocol Buffers (a.k.a., protobuf) are Google's language-neutral, platform-neutral, extensible mechanism for serializing structured data. You can learn more about it in protobuf's documentation.

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.

Working With Protobuf Source Code

Most users will find working from supported releases to be the easiest path.

If you choose to work from the head revision of the main branch your build will occasionally be broken by source-incompatible changes and insufficiently-tested (and therefore broken) behavior.

If you are using C++ or otherwise need to build protobuf from source as a part of your project, you should pin to a release commit on a release branch.

This is because even release branches can experience some instability in between release commits.

Protobuf Compiler Installation

The protobuf 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 GitHub release page.

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 repository.

These pre-built binaries are only provided for released versions. If you want to use the github main 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 Runtime Installation

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:

LanguageSource
C++ (include C++ runtime and protoc)src
Javajava
Pythonpython
Objective-Cobjectivec
C#csharp
Rubyruby
Goprotocolbuffers/protobuf-go
PHPphp
Dartdart-lang/protobuf
JavaScriptprotocolbuffers/protobuf-javascript

Quick Start

The best way to learn how to use protobuf is to follow the tutorials in our developer guide.

If you want to learn from code examples, take a look at the examples in the examples directory.

Documentation

The complete documentation is available at the Protocol Buffers doc site.

Support Policy

Read about our version support policy to stay current on support timeframes for the language libraries.

Developer Community

To be alerted to upcoming changes in Protocol Buffers and connect with protobuf developers and users, join the Google Group.