tree c2544c67b246171033e9d8ebb41cef5ab8f667cc
parent 13fd8f52382c13b1db520f12aa4560878e36c050
author David 'Digit' Turner <digit@google.com> 1706653973 +0100
committer CQ Bot <fuchsia-internal-scoped@luci-project-accounts.iam.gserviceaccount.com> 1707313121 +0000

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>