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path: root/indra/newview/scripts/lua/WaitQueue.lua
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2024-03-27Enhance Lua debugging output.Nat Goodspeed
Don't use "debug" as the name of a function to conditionally write debug messages: "debug" is a Luau built-in library, and assigning that name locally would shadow the builtin. Use "dbg" instead. Recast fiber.print_all() as fiber.format_all() that returns a string; then print_all() is simply print(format_all()). This refactoring allows us to use dbg(format_all()) as well. Add a couple new dbg() messages at fiber state changes.
2024-03-25Add LL. prefix to viewer entry points, fix existing references.Nat Goodspeed
2024-03-23Make leap.request() work even from Lua's main thread.Nat Goodspeed
Recast fiber.yield() as internal function scheduler(). Move fiber.run() after it so it can call scheduler() as a local function. Add new fiber.yield() that also calls scheduler(); the added value of this new fiber.yield() over plain scheduler() is that if scheduler() returns before the caller is ready (because the configured set_idle() function returned non-nil), it produces an explicit error rather than returning to its caller. So the caller can assume that when fiber.yield() returns normally, the calling fiber is ready. This allows any fiber, including the main thread, to call fiber.yield() or fiber.wait(). This supports using leap.request(), which posts a request and then waits on a WaitForReqid, which calls ErrorQueue:Dequeue(), which calls fiber.wait(). WaitQueue:_wake_waiters() must call fiber.status() instead of coroutine.status() so it understands the special token 'main'. Add a new llluamanager_test.cpp test to exercise calling leap.request() from Lua's main thread.
2024-03-22Fix a couple bugs in fiber.lua machinery.Nat Goodspeed
This fixes a hang if the Lua script explicitly calls fiber.run() before LuaState::expr()'s implicit fiber.run() call. Make fiber.run() remove the calling fiber from the ready list to avoid an infinite loop when all other fibers have terminated: "You're ready!" "Okay, yield()." "You're ready again!" ... But don't claim it's waiting, either, because then when all other fibers have terminated, we'd call idle() in the vain hope that something would make that one last fiber ready. WaitQueue:_wake_waiters() needs to wake waiting fibers if the queue's not empty OR it's been closed. Introduce leap.WaitFor:close() to close the queue gracefully so that a looping waiter can terminate, instead of using WaitFor:exception(), which stops the whole script once it propagates. Make leap's cleanup() function call close(). Streamline fiber.get_name() by using 'or' instead of if ... then. Streamline fiber.status() and fiber.set_waiting() by using table.find() instead of a loop.
2024-03-21WIP: Add fiber.lua module and use in leap.lua and WaitQueue.lua.Nat Goodspeed
fiber.lua goes beyond coro.lua in that it distinguishes ready suspended coroutines from waiting suspended coroutines, and presents a rudimentary scheduler in fiber.yield(). yield() can determine that when all coroutines are waiting, it's time to retrieve the next incoming event from the viewer. Moreover, it can detect when all coroutines have completed and exit without being explicitly told. fiber.launch() associates a name with each fiber for debugging purposes. fiber.get_name() retrieves the name of the specified fiber, or the running fiber. fiber.status() is like coroutine.status(), but can return 'ready' or 'waiting' instead of 'suspended'. fiber.yield() leaves the calling fiber ready, but lets other ready fibers run. fiber.wait() suspends the calling fiber and lets other ready fibers run. fiber.wake(), called from some other coroutine, returns the passed fiber to ready status for a future call to fiber.yield(). fiber.run() drives the scheduler to run all fibers to completion. If, on completion of the subject Lua script, LuaState::expr() detects that the script loaded fiber.lua, it calls fiber.run() to finish running any dangling fibers. This lets a script make calls to fiber.launch() and then just fall off the end, leaving the implicit fiber.run() call to run them all. fiber.lua is designed to allow the main thread, as well as explicitly launched coroutines, to make leap.request() calls. This part still needs debugging. The leap.lua module now configures a fiber.set_idle() function that honors leap.done(), but calls get_event_next() and dispatches the next incoming event. leap.request() and generate() now leave the reqid stamp in the response. This lets a caller handle subsequent events with the same reqid, e.g. for LLLuaFloater. Remove leap.process(): it has been superseded by fiber.run(). Remove leap.WaitFor:iterate(): unfortunately that would run afoul of the Luau bug that prevents suspending the calling coroutine within a generic 'for' iterator function. Make leap.lua use weak tables to track WaitFor objects. Make WaitQueue:Dequeue() call fiber.wait() to suspend its caller when the queue is empty, and Enqueue() call fiber.wake() to set it ready again when a new item is pushed. Make llluamanager_test.cpp's leap test script use the fiber module to launch coroutines, instead of the coro module. Fix a bug in which its drain() function was inadvertently setting and testing the global 'item' variable instead of one local to the function. Since some other modules had the same bug, it was getting confused. Also add printf.lua, providing a printf() function. printf() is short for print(string.format()), but it can also print tables: anything not a number or string is formatted using the inspect() function. Clean up some LL_DEBUGS() output left over from debugging lua_tollsd().
2024-03-11Make WaitQueue:_wait_waiters() skip dead coroutines.Nat Goodspeed
That is, skip coroutines that have gone dead since they decided to wait on Dequeue().
2024-03-07Finish adding leap.WaitFor and WaitForReqid. Untested.Nat Goodspeed
2024-03-07Finish WaitQueue, ErrorQueue; add util.count(), join(); extend qtest.Nat Goodspeed
For WaitQueue, nail down the mechanism for declaring a subclass and for calling a base-class method from a subclass override. Break out new _wake_waiters() method from Enqueue(): we need to do the same from close(), in case there are waiting consumers. Also, in Lua, 0 is not false. Instead of bundling a normal/error flag with every queued value, make ErrorQueue overload its _closed attribute. Once you call ErrorQueue:Error(), every subsequent Dequeue() call by any consumer will re-raise the same error. util.count() literally counts entries in a table, since #t is documented to be unreliable. (If you create a list with 5 entries and delete the middle one, #t might return 2 or it might return 5, but it won't return 4.) util.join() fixes a curious omission from Luau's string library: like Python's str.join(), it concatenates all the strings from a list with an optional separator. We assume that incrementally building a list of strings and then doing a single allocation for the desired result string is cheaper than reallocating each of a sequence of partial concatenated results. Add qtest test that posts individual items to a WaitQueue, waking waiting consumers to retrieve the next available result. Add test proving that calling ErrorQueue:Error() propagates the error to all consumers.
2024-03-06WIP: Unfinished Queue.lua, WaitQueue.lua, ErrorQueue.lua, leap.lua.Nat Goodspeed
Also qtest.lua to exercise the queue classes and inspect.lua (from https://github.com/kikito/inspect.lua) for debugging.