From 2dc003779443db99f46b3db6d17a1954f7b141dd Mon Sep 17 00:00:00 2001
From: Nat Goodspeed <nat@lindenlab.com>
Date: Sat, 23 Mar 2024 17:43:07 +0900
Subject: Make leap.request() work even from Lua's main thread.

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.
---
 indra/newview/tests/llluamanager_test.cpp | 43 ++++++++++++++++++++++++++-----
 1 file changed, 37 insertions(+), 6 deletions(-)

(limited to 'indra/newview/tests')

diff --git a/indra/newview/tests/llluamanager_test.cpp b/indra/newview/tests/llluamanager_test.cpp
index d1beed84ef..0fd91c1354 100644
--- a/indra/newview/tests/llluamanager_test.cpp
+++ b/indra/newview/tests/llluamanager_test.cpp
@@ -307,9 +307,43 @@ namespace tut
     template<> template<>
     void object::test<5>()
     {
-        set_test_name("test leap.lua");
+        set_test_name("leap.request() from main thread");
         const std::string lua(
-            "-- test leap.lua\n"
+            "-- leap.request() from main thread\n"
+            "\n"
+            "leap = require 'leap'\n"
+            "\n"
+            "return {\n"
+            "    a=leap.request('echo', {data='a'}).data,\n"
+            "    b=leap.request('echo', {data='b'}).data\n"
+            "}\n"
+        );
+
+        LLEventStream pump("echo", false);
+        LLTempBoundListener conn{
+            pump.listen(
+                "test<5>()",
+                listener([](const LLSD& data)
+                {
+                    LL_DEBUGS("Lua") << "echo pump got: " << data << LL_ENDL;
+                    LLEventPumps::instance().post(
+                        data["reply"],
+                        llsd::map("reqid", data["reqid"], "data", data["data"]));
+                }))
+        };
+
+        LuaState L;
+        auto [count, result] = LLLUAmanager::waitScriptLine(L, lua);
+        ensure_equals("Lua script didn't return item", count, 1);
+        ensure_equals("echo failed", result, llsd::map("a", "a", "b", "b"));
+    }
+
+    template<> template<>
+    void object::test<6>()
+    {
+        set_test_name("interleave leap.request() responses");
+        const std::string lua(
+            "-- interleave leap.request() responses\n"
             "\n"
             "fiber = require('fiber')\n"
             "leap = require('leap')\n"
@@ -359,16 +393,13 @@ namespace tut
             "fiber.launch('catchall', drain, catchall)\n"
             "fiber.launch('catch_special', drain, catch_special)\n"
             "fiber.launch('requester(a)', requester, 'a')\n"
-            "-- requester(a)\n"
             "fiber.launch('requester(b)', requester, 'b')\n"
-            "fiber.run()\n"
-            "-- fiber.print_all()\n"
         );
 
         LLSD requests;
         LLEventStream pump("testpump", false);
         LLTempBoundListener conn{
-            pump.listen("test<5>()",
+            pump.listen("test<6>()",
                         listener([&requests](const LLSD& data)
                         {
                             LL_DEBUGS("Lua") << "testpump got: " << data << LL_ENDL;
-- 
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