If a newly spawned thread called getThreadId or getThreadHandle before
the spawning thread finished saving the thread handle, then the
handle/id would be used uninitialized. This would cause the threading
tests to fail since isCurrentThread would return false, and if Minetest
is built with C++11 support the std::thread object pointer would be
dereferenced while ininitialized, causing a segmentation fault.
This fixes the issue by using a mutex to force the spawned thread to
wait for the spawning thread to finish initializing the thread object.
An alternative way to handle this would be to also set the thread
handle/id in the started thread but this wouldn't work for C++11
builds because there's no way to get the partially constructed object.
The initial problem was that mutex_auto_lock.h tries to use std::unique_lock<std::mutex>
despite mutex.h not using C++11's std::mutex on Windows. The problem here is the mismatch
between C++11 usage conditions of the two headers. This commit moves the decision logic
to threads.h and makes sure mutex.h, mutex_auto_lock.h and event.h all use the same features.
The source used a hodge-podge of different combinations of different
macros to check for linux: 'linux', '__linux', '__linux__'.
As '__linux__' is standard (Posix), and the others are not, the source
now uniformly uses __linux__. If either linux or __linux are defined,
it is made sure that __linux__ is defined as well.
The Atomic implementation was only partially correct, and was very complex.
Use locks for sake of simplicity, following KISS principle.
Only remaining atomic operation use is time of day speed, because that
really is only read + written.
Also fixes a bug with m_time_conversion_skew only being decremented, never
incremented (Regresion from previous commit).
atomic.h changes:
* Add GenericAtomic<T> class for non-integral types like floats.
* Remove some last remainders from atomic.h of the volatile use.
Cleanup:
* Remove volatile keyword, it is of no use at all. [1]
* Remove the enable_if stuff. It had no use either.
The most likely explanation why the enable_if stuff was there is that it
was used as something like a STATIC_ASSERT to verify that sizeof(T) is not larger
than sizeof(void *). This check however is not just misplaced in a place where we
already use a lock, it isn't needed at all, as gcc will just generate a call to
to the runtime if it compiles for platforms that don't support atomic instructions.
The runtime will then most likely use locks.
Code style fixes:
* Prefix name of the mutex
* Line everything up nicely, where it makes things look nice
* Filling \ continuations with spaces is code style rule
Added operations on the atomic var:
* Compare and swap
* Swap
The second point of the cleanup also fixes the Android build of the next commit.
[1]: http://stackoverflow.com/q/2484980
For several years now, the lua script lock has been completely broken.
This commit fixes the main issue (creation of a temporary rather than
scoped object), and fixes a subsequent deadlock issue caused by
nested script API calls by adding support for recursive mutexes.
Use this macro to disallow copying of an object using the assignment
operator or copy constructor. This catches otherwise silent-but-deadly
mistakes such as "ServerMap map = env->getMap();" at compile time.
If so desired, it is still possible to copy a class, but it now requires
an explicit call to memcpy or std::copy.
- Fix some incompatibilities with obscure platforms (AIX and WinCE)
- Clean up Thread class interface
- Add m_ prefix to private member variables
- Simplify platform-dependent logic, reducing preprocessor
conditional clauses and improving readibility
- Add Thread class documentation
- Add warning log level
- Change debug_log_level setting to enumeration string
- Map Irrlicht log events to MT log events
- Encapsulate log_* functions and global variables into a class, Logger
- Unify dstream with standard logging mechanism
- Unify core.debug() with standard core.log() script API
Commit
e4bff8be94c0db4f94e63ad448d0eeb869ccdbbd - Clean up threading
by @ShadowNinja has broken the OSX build.
Including things inside a namespace isn't good.
Also fixes#3124.
* Rename everything.
* Strip J prefix.
* Change UpperCamelCase functions to lowerCamelCase.
* Remove global (!) semaphore count mutex on OSX.
* Remove semaphore count getter (unused, unsafe, depended on internal
API functions on Windows, and used a hack on OSX).
* Add `Atomic<type>`.
* Make `Thread` handle thread names.
* Add support for C++11 multi-threading.
* Combine pthread and win32 sources.
* Remove `ThreadStarted` (unused, unneeded).
* Move some includes from the headers to the sources.
* Move all of `Event` into its header (allows inlining with no new includes).
* Make `Event` use `Semaphore` (except on Windows).
* Move some porting functions into `Thread`.
* Integrate logging with `Thread`.
* Add threading test.
