From 66981fab0b3c8dcc3a031d50710a2b24ec6b0603 Mon Sep 17 00:00:00 2001 From: Nat Goodspeed Date: Thu, 10 May 2018 21:46:07 -0400 Subject: SL-793: Use Boost.Fiber instead of the "dcoroutine" library. Longtime fans will remember that the "dcoroutine" library is a Google Summer of Code project by Giovanni P. Deretta. He originally called it "Boost.Coroutine," and we originally added it to our 3p-boost autobuild package as such. But when the official Boost.Coroutine library came along (with a very different API), and we still needed the API of the GSoC project, we renamed the unofficial one "dcoroutine" to allow coexistence. The "dcoroutine" library had an internal low-level API more or less analogous to Boost.Context. We later introduced an implementation of that internal API based on Boost.Context, a step towards eliminating the GSoC code in favor of official, supported Boost code. However, recent versions of Boost.Context no longer support the API on which we built the shim for "dcoroutine." We started down the path of reimplementing that shim using the current Boost.Context API -- then realized that it's time to bite the bullet and replace the "dcoroutine" API with the Boost.Fiber API, which we've been itching to do for literally years now. Naturally, most of the heavy lifting is in llcoros.{h,cpp} and lleventcoro.{h,cpp} -- which is good: the LLCoros layer abstracts away most of the differences between "dcoroutine" and Boost.Fiber. The one feature Boost.Fiber does not provide is the ability to forcibly terminate some other fiber. Accordingly, disable LLCoros::kill() and LLCoprocedureManager::shutdown(). The only known shutdown() call was in LLCoprocedurePool's destructor. We also took the opportunity to remove postAndSuspend2() and its associated machinery: FutureListener2, LLErrorEvent, errorException(), errorLog(), LLCoroEventPumps. All that dual-LLEventPump stuff was introduced at a time when the Responder pattern was king, and we assumed we'd want to listen on one LLEventPump with the success handler and on another with the error handler. We have never actually used that in practice. Remove associated tests, of course. There is one other semantic difference that necessitates patching a number of tests: with "dcoroutine," fulfilling a future IMMEDIATELY resumes the waiting coroutine. With Boost.Fiber, fulfilling a future merely marks the fiber as ready to resume next time the scheduler gets around to it. To observe the test side effects, we've inserted a number of llcoro::suspend() calls -- also in the main loop. For a long time we retained a single unit test exercising the raw "dcoroutine" API. Remove that. Eliminate llcoro_get_id.{h,cpp}, which provided llcoro::get_id(), which was a hack to emulate fiber-local variables. Since Boost.Fiber has an actual API for that, remove the hack. In fact, use (new alias) LLCoros::local_ptr for LLSingleton's dependency tracking in place of llcoro::get_id(). In CMake land, replace BOOST_COROUTINE_LIBRARY with BOOST_FIBER_LIBRARY. We don't actually use the Boost.Coroutine for anything (though there exist plausible use cases). --- indra/linux_crash_logger/CMakeLists.txt | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'indra/linux_crash_logger/CMakeLists.txt') diff --git a/indra/linux_crash_logger/CMakeLists.txt b/indra/linux_crash_logger/CMakeLists.txt index 315aed8d11..d789c850a0 100644 --- a/indra/linux_crash_logger/CMakeLists.txt +++ b/indra/linux_crash_logger/CMakeLists.txt @@ -69,7 +69,7 @@ target_link_libraries(linux-crash-logger ${LLMATH_LIBRARIES} ${LLCOREHTTP_LIBRARIES} ${LLCOMMON_LIBRARIES} - ${BOOST_COROUTINE_LIBRARY} + ${BOOST_FIBER_LIBRARY} ${BOOST_CONTEXT_LIBRARY} ${UI_LIBRARIES} ${DB_LIBRARIES} -- cgit v1.2.3