The shell was already designed to cleanly shut down the VM but it couldnt
earlier as |Dart_Initialize| could never be called after a |Dart_Cleanup|. This
meant that shutting down an engine instance could not shut down the VM to save
memory because newly created engines in the process after that point couldn't
restart the VM. There can only be one VM running in a process at a time.
This patch separate the previous DartVM object into one that references a
running instance of the DartVM and a set of immutable dependencies that
components can reference even as the VM is shutting down.
Unit tests have been added to assert that non-overlapping engine launches use
difference VM instances.
The behavior of acquire+release annotation handling has changed in
https://reviews.llvm.org/D49355 which breaks the build with the new
Clang. However, as has been pointed out, the acquire+release isn't
the right way to prevent double locking as the annotations negate
each other; the correct way is to use excludes or negative requires.
Using excludes annotations also requires using std::lock_guard instead
of std::unique_lock because the latter doesn't have the thread
annotations due to deferred locking which is not needed in Flutter and
so std::lock_guard is a sufficient alternative.
* Reland "Added IsolateNameServer functionality (#5410)"
This reverts commit c3976b3c7183f479717bffed3f640fb92afbd3dc.
* Fixed issue with isolate_name_server_test which caused test to timeout
* Disabled thread_annotations on Android as they aren't supported in the
NDK headers for std::mutex. Readded thread annotations to
IsolateNameServer.
* Added IsolateNameServer functionality, which allows for the association
of string names with isolate SendPort ids that can be used to establish
inter-isolate communications.
