JavaGlobal was unconditionally attaching to (okay) and detaching from (bad)
the current thread during destruction. We don't want to do this if the
destructor gets called from an attached thread. Instead, use GetEnv to
first try to get the environment, and only attach and detach if it returns
an error saying the thread is detached.
Also, make sure notifier callbacks appropriately free Java locals to avoid
running out of local variable space.
During JVM shutdown, some JNI calls may not return, so it's not possible to
reliably perform a join() during static variable destruction (which occurs
as the JVM unloads the JNI module).
Also, due to static variable destruction, it's not safe to use any members
of a static class instance from a separate thread of execution.
SafeThread is a templated thread class and a related owner class that's
designed for safe operation and shutdown of threads in the presence of
callbacks that may not return. It also passes ownership of variables from
the static instance to the thread, so the thread can safely operate until
it exits (the last operation of the thread being to destroy its instance).
Notifiers, RpcServer, and Logger now use SafeThread to ensure race-free
destruction in both C++ and Java.
All Java callback threads are now marked as Java daemon threads so they
don't keep the JVM running after main() terminates.
All Java callback threads are now named so their purpose is more easily
identified in a debugger.
Add SetRpcServerOnStart and SetRpcServerOnExit (similar to Listener).
The previous use of a timeout resulting in thread detach instead of thread
join resulted in a race condition on Mac between destruction and thread
closeout. This commit removes the detach functionality and uses dup2() to
on Linux/Mac and connecting to itself on Windows to try to ensure accept()
exits.
Each call to AttachCurrentThread results in a new Java thread object being
created. This is inefficient and also causes debugging issues with Eclipse
due to constant creation and removal of threads. Now AttachCurrentThread is
only called once for (all) listeners and once for logging (if used).
Previously this would always return false due to how explicit bool is
evaluated in a return context.
Also add a test for this function.
Reported by: jcreigh
This is safe because of the way writes are performed: for each transmission,
all outgoing messages are concatenated in memory and only a single write()
syscall is made.
These are good to have for backwards compatibility, but discouraged for new
development (default-taking functions should be used instead). The reason
is that the exceptions must be explicitly handled and may initially work but
then fail at an inopportune moment.
Mark the similar Java functions as deprecated as well for the same reason.
Update all the docs for consistency.
Mark overridden functions as such in both C++ and Java.
Make IsPersistent and GetFlags const in C++.
no-unused-private-field for Mac builds. Gradle also now works
with the classifier-based dependency system, rather than having
separate repos for every level.
Change-Id: I2eb87391181e91b5675e3e982e4d915be83e14ea
