StatCache: Provide timestamp cache abstraction

This introduces a new class named StatCache to abstract
timestamp cache implementations from DiskInterface itself.

For now, this only moves the Win32-specific implementation
to stat_cache-win32.cc, and provides a non-caching Posix
backend. This does not modifies Ninja's behavior in any
way.

In particular, this does not improve the performance
of the Win32 StatCache instance, which is only a
"timestamp preloader", and is not capable of detecting
changes between incremental builds.

+ Introduces the DiskInterface::Sync() method which can
  be used to ensure that changes to the filesystem that
  happened outside of DiskInterface() calls are properly
  accounted for.

+ Change StatFile() to GetFileTimestamp() in util.h
  to avoid confusion with the StatFile() method of the
  StatCache class.

A future CL will add an inotify-based cache to speed
up incremental builds in persistent mode on Linux.

Fuchsia-Topic: persistent-mode
Original-Change-Id: I997f8f6a35131bcb1cf47ed71b6bbab43417d726
Original-Change-Id: I02e8a6e499d9593eff20912d1dd9836b2ca2ea86
Change-Id: I0f68e8165b8f269decea5d4ee52aa2f25349e44d
Reviewed-on: https://fuchsia-review.googlesource.com/c/third_party/github.com/ninja-build/ninja/+/981655
Reviewed-by: David Fang <fangism@google.com>
Commit-Queue: David Turner <digit@google.com>
10 files changed
tree: c2544c67b246171033e9d8ebb41cef5ab8f667cc
  1. .github/
  2. doc/
  3. misc/
  4. src/
  5. windows/
  6. .clang-format
  7. .clang-tidy
  8. .editorconfig
  9. .gitignore
  10. appveyor.yml
  11. CMakeLists.txt
  12. configure.py
  13. CONTRIBUTING.md
  14. COPYING
  15. README.fuchsia
  16. README.md
  17. RELEASING.md
README.md

Ninja

Ninja is a small build system with a focus on speed. https://ninja-build.org/

See the manual or doc/manual.asciidoc included in the distribution for background and more details.

Binaries for Linux, Mac and Windows are available on GitHub. Run ./ninja -h for Ninja help.

Installation is not necessary because the only required file is the resulting ninja binary. However, to enable features like Bash completion and Emacs and Vim editing modes, some files in misc/ must be copied to appropriate locations.

If you're interested in making changes to Ninja, read CONTRIBUTING.md first.

Building Ninja itself

You can either build Ninja via the custom generator script written in Python or via CMake. For more details see the wiki.

Python

./configure.py --bootstrap

This will generate the ninja binary and a build.ninja file you can now use to build Ninja with itself.

CMake

cmake -Bbuild-cmake
cmake --build build-cmake

The ninja binary will now be inside the build-cmake directory (you can choose any other name you like).

To run the unit tests:

./build-cmake/ninja_test