Here is V2 of my patch series to add a builtin FSMonitor daemon to Git.

V2 includes addresses most of the review comments from the RFC and many of
the issues seen during out beta-testing with selected GVFS users. However,
there are still a few items that I need to address:

[ ] Revisit the how the client handles the IPC_STATE__NOT_LISTENING state
(where a daemon appears to be running, but is non-responsive) [ ] Revisit
use of global core_fsmonitor as both a pathname and a boolean. The existing
fsmonitor code uses it as the pathname to the fsmonitor hook and as a flag
to indicate that a hook is configured. [ ] Consider having daemon chdir()
out of the working directory to avoid directory handle issues on Windows. [
] Some documentation recommendations. [ ] Split up the commit containing the
tests and move some earlier in patch series. [ ] Move my FSMonitor PREREQ to
test-lib.sh instead of having it in my test scripts. [ ] Document
performance gains. [ ] On Windows, If the daemon is started as an elevated
process, then client commands might not have access to communicate with it.
[ ] Review if/how we decide to shutdown the FSMonitor daemon after and a
significant idle period. [ ] Investigate ways to temporarily shutdown
FSMonitor daemons processes so that the Git for Windows installer can
install an upgrade.

In this version, the first commit updates the Simple IPC API to make it
easier to pass binary data using {char *, size_t} rather than assuming that
the message is a null-terminated string. FSMonitor does not use binary
messages and doesn't really need this API change, but I thought it best to
fix the API now before we have other callers of IPC.

This V2 version will hopefully be previewed as an experimental feature in
Git for Windows v2.32.0.windows.*.

Jeff Hostetler (26):
  simple-ipc: preparations for supporting binary messages.
  fsmonitor--daemon: man page
  fsmonitor--daemon: update fsmonitor documentation
  fsmonitor-ipc: create client routines for git-fsmonitor--daemon
  help: include fsmonitor--daemon feature flag in version info
  fsmonitor--daemon: add a built-in fsmonitor daemon
  fsmonitor--daemon: implement client command options
  t/helper/fsmonitor-client: create IPC client to talk to FSMonitor
    Daemon
  fsmonitor-fs-listen-win32: stub in backend for Windows
  fsmonitor-fs-listen-macos: stub in backend for MacOS
  fsmonitor--daemon: implement daemon command options
  fsmonitor--daemon: add pathname classification
  fsmonitor--daemon: define token-ids
  fsmonitor--daemon: create token-based changed path cache
  fsmonitor-fs-listen-win32: implement FSMonitor backend on Windows
  fsmonitor-fs-listen-macos: add macos header files for FSEvent
  fsmonitor-fs-listen-macos: implement FSEvent listener on MacOS
  fsmonitor--daemon: implement handle_client callback
  fsmonitor--daemon: periodically truncate list of modified files
  fsmonitor--daemon: use a cookie file to sync with file system
  fsmonitor: enhance existing comments
  fsmonitor: force update index after large responses
  t7527: create test for fsmonitor--daemon
  p7519: add fsmonitor--daemon
  t7527: test status with untracked-cache and fsmonitor--daemon
  t/perf: avoid copying builtin fsmonitor files into test repo

Johannes Schindelin (2):
  config: FSMonitor is repository-specific
  fsmonitor: introduce `core.useBuiltinFSMonitor` to call the daemon via
    IPC

 .gitignore                                   |    1 +
 Documentation/config/core.txt                |   56 +-
 Documentation/git-fsmonitor--daemon.txt      |   75 +
 Documentation/git-update-index.txt           |   27 +-
 Documentation/githooks.txt                   |    3 +-
 Makefile                                     |   16 +
 builtin.h                                    |    1 +
 builtin/fsmonitor--daemon.c                  | 1511 ++++++++++++++++++
 builtin/update-index.c                       |    4 +-
 compat/fsmonitor/fsmonitor-fs-listen-macos.c |  497 ++++++
 compat/fsmonitor/fsmonitor-fs-listen-win32.c |  553 +++++++
 compat/fsmonitor/fsmonitor-fs-listen.h       |   49 +
 compat/simple-ipc/ipc-unix-socket.c          |   14 +-
 compat/simple-ipc/ipc-win32.c                |   14 +-
 config.c                                     |    9 +-
 config.h                                     |    2 +-
 config.mak.uname                             |    4 +
 contrib/buildsystems/CMakeLists.txt          |    8 +
 fsmonitor--daemon.h                          |  140 ++
 fsmonitor-ipc.c                              |  179 +++
 fsmonitor-ipc.h                              |   48 +
 fsmonitor.c                                  |  132 +-
 git.c                                        |    1 +
 help.c                                       |    4 +
 repo-settings.c                              |    3 +
 repository.h                                 |    2 +
 simple-ipc.h                                 |    7 +-
 t/helper/test-fsmonitor-client.c             |  125 ++
 t/helper/test-simple-ipc.c                   |   34 +-
 t/helper/test-tool.c                         |    1 +
 t/helper/test-tool.h                         |    1 +
 t/perf/p7519-fsmonitor.sh                    |   42 +-
 t/perf/perf-lib.sh                           |    2 +-
 t/t7527-builtin-fsmonitor.sh                 |  572 +++++++
 34 files changed, 4069 insertions(+), 68 deletions(-)
 create mode 100644 Documentation/git-fsmonitor--daemon.txt
 create mode 100644 builtin/fsmonitor--daemon.c
 create mode 100644 compat/fsmonitor/fsmonitor-fs-listen-macos.c
 create mode 100644 compat/fsmonitor/fsmonitor-fs-listen-win32.c
 create mode 100644 compat/fsmonitor/fsmonitor-fs-listen.h
 create mode 100644 fsmonitor--daemon.h
 create mode 100644 fsmonitor-ipc.c
 create mode 100644 fsmonitor-ipc.h
 create mode 100644 t/helper/test-fsmonitor-client.c
 create mode 100755 t/t7527-builtin-fsmonitor.sh

base-commit: b0c09ab8796fb736efa432b8e817334f3e5ee75a

Submitted-As: https://lore.kernel.org/git/pull.923.v2.git.1621691828.gitgitgadget@gmail.com
In-Reply-To: https://lore.kernel.org/git/pull.923.git.1617291666.gitgitgadget@gmail.com