[PATCH] D74371: [DirectoryWatcher] Fix misuse of FSEvents API and data race

[Ben Langmuir via Phabricator via cfe-commits]

benlangmuir created this revision.
benlangmuir added reviewers: jkorous, akyrtzi.
Herald added subscribers: cfe-commits, dexonsmith.
Herald added a project: clang.

I observed two bugs in the DirectoryWatcher on macOS

      

1. We were calling FSEventStreamStop and FSEventStreamInvalidate before we called FSEventStreamStart and FSEventStreamSetDispatchQueue, if the DirectoryWatcher was destroyed before the initial async work was done. This violates the requirements of the FSEvents API.

2. Calls to Receiver could race between the initial work and the invalidation during destruction.

The second issue is easier to see when using TSan.

      

rdar://59215667


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D74371

Files:
  clang/lib/DirectoryWatcher/mac/DirectoryWatcher-mac.cpp
  clang/unittests/DirectoryWatcher/DirectoryWatcherTest.cpp

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