Replace the call to `FSEventStreamScheduleWithRunLoop()` function with
the suggested `FSEventStreamSetDispatchQueue()` function.
The MacOS version of the builtin FSMonitor feature uses the
`FSEventStreamScheduleWithRunLoop()` function to drive the event loop
and process FSEvents from the system. This routine has now been
deprecated by Apple. The MacOS 13 (Ventura) compiler tool chain now
generates a warning when compiling calls to this function. In
DEVELOPER=1 mode, this now causes a compile error.
The `FSEventStreamSetDispatchQueue()` function is conceptually similar
and is the suggested replacement. However, there are some subtle
thread-related differences.
Previously, the event stream would be processed by the
`fsm_listen__loop()` thread while it was in the `CFRunLoopRun()`
method. (Conceptually, this was a blocking call on the lifetime of
the event stream where our thread drove the event loop and individual
events were handled by the `fsevent_callback()`.)
With the change, a "dispatch queue" is created and FSEvents will be
processed by a hidden queue-related thread (that calls the
`fsevent_callback()` on our behalf). Our `fsm_listen__loop()` thread
maintains the original blocking model by waiting on a mutex/condition
variable pair while the hidden thread does all of the work.
While the deprecated API used by the original were introduced in
macOS 10.5 (Oct 2007), the API used by the updated code were
introduced back in macOS 10.6 (Aug 2009) and has been available
since then. So this change _could_ break those who have happily
been using 10.5 (if there were such people), but these two dates
both predate the oldest versions of macOS Apple seems to support
anyway, so we should be safe.
Signed-off-by: Jeff Hostetler <jeffhostetler@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Include MacOS system declarations to allow us to use FSEvent and
CoreFoundation APIs. We need different versions of the declarations
for GCC vs. clang because of compiler and header file conflicts.
While it is quite possible to #include Apple's CoreServices.h when
compiling C source code with clang, trying to build it with GCC
currently fails with this error:
In file included
from /Library/Developer/CommandLineTools/SDKs/MacOSX10.14.sdk/System/...
...Library/Frameworks/Security.framework/Headers/AuthSession.h:32,
from /Library/Developer/CommandLineTools/SDKs/MacOSX10.14.sdk/System/...
...Library/Frameworks/Security.framework/Headers/Security.h:42,
from /Library/Developer/CommandLineTools/SDKs/MacOSX10.14.sdk/System/...
...Library/Frameworks/CoreServices.framework/Frameworks/...
...OSServices.framework/Headers/CSIdentity.h:43,
from /Library/Developer/CommandLineTools/SDKs/MacOSX10.14.sdk/System/...
...Library/Frameworks/CoreServices.framework/Frameworks/...
...OSServices.framework/Headers/OSServices.h:29,
from /Library/Developer/CommandLineTools/SDKs/MacOSX10.14.sdk/System/...
...Library/Frameworks/CoreServices.framework/Frameworks/...
...LaunchServices.framework/Headers/IconsCore.h:23,
from /Library/Developer/CommandLineTools/SDKs/MacOSX10.14.sdk/System/...
...Library/Frameworks/CoreServices.framework/Frameworks/...
...LaunchServices.framework/Headers/LaunchServices.h:23,
from /Library/Developer/CommandLineTools/SDKs/MacOSX10.14.sdk/System/...
...Library/Frameworks/CoreServices.framework/Headers/CoreServices.h:45,
/Library/Developer/CommandLineTools/SDKs/MacOSX10.14.sdk/System/...
...Library/Frameworks/Security.framework/Headers/Authorization.h:193:7:
error: variably modified 'bytes' at file scope
193 | char bytes[kAuthorizationExternalFormLength];
| ^~~~~
The underlying reason is that GCC (rightfully) objects that an `enum`
value such as `kAuthorizationExternalFormLength` is not a constant
(because it is not, the preprocessor has no knowledge of it, only the
actual C compiler does) and can therefore not be used to define the size
of a C array.
This is a known problem and tracked in GCC's bug tracker:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93082
In the meantime, let's not block things and go the slightly ugly route
of declaring/defining the FSEvents constants, data structures and
functions that we need, so that we can avoid above-mentioned issue.
Let's do this _only_ for GCC, though, so that the CI/PR builds (which
build both with clang and with GCC) can guarantee that we _are_ using
the correct data types.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
