Reintroduce LLCoros::killreq() to request killing a named coroutine.

Make LLCoros constructor echo "LLApp" status-change events on new "LLCoros"
event pump.

Rename LLCoros::kill() to killreq() because this operation only registers a
request for the named coroutine to terminate next time it calls checkStop().
Add a new CoroData member to record the name of the coroutine requesting
termination. killreq() sets that and also posts "killreq" to "LLCoros".

Add an optional final-cleanup callback to LLCoros::checkStop(). Make
checkStop() check for a pending killreq() request as well as viewer
termination. Introduce new LLCoros::Killed exception for that case.

Introduce LLCoros::getStopListener(), with two overloads, to encapsulate some
of the messy logic to listen (perhaps temporarily) for viewer shutdown. Both
overloads are for use by code at the source end of a queue or promise or other
resource for which coroutines might still be waiting at viewer shutdown time.
One overload is specifically for when the caller knows the name of the one and
only coroutine that will wait on the resource (e.g. because the caller IS that
coroutine). That overload honors killreq().

Use getStopListener() to simplify the four existing places where we set up
such a listener. Add a fifth: also make WorkQueue listen for viewer shutdown
(resolving a TODO comment).

Remove LLLUAmanager::terminateScript(), getTerminationList() and the static
sTerminationList. In the Lua interrupt callback, instead of checking
sTerminationList, call LLCoros::checkStop().

Change LLFloaterLUAScripts terminate-script logic to call LLCoros::killreq()
instead of posting on "LLLua" and calling LLLUAmanager::terminateScript().

Drop LLApp::setStatus() posting to "LLLua" LLEventPump: the above makes that
moot.

1 files changed, 103 insertions, 24 deletions

diff --git a/indra/llcommon/llcoros.cpp b/indra/llcommon/llcoros.cpp
index c13900f74a..1926941d1f 100644
--- a/indra/llcommon/llcoros.cpp
+++ b/indra/llcommon/llcoros.cpp
@@ -51,18 +51,19 @@
 #endif
 // other Linden headers
 #include "llapp.h"
-#include "lltimer.h"
-#include "llevents.h"
 #include "llerror.h"
-#include "stringize.h"
+#include "llevents.h"
 #include "llexception.h"
+#include "llsdutil.h"
+#include "lltimer.h"
+#include "stringize.h"
 
 #if LL_WINDOWS
 #include <excpt.h>
 #endif
 
 // static
-LLCoros::CoroData& LLCoros::get_CoroData(const std::string& caller)
+LLCoros::CoroData& LLCoros::get_CoroData(const std::string&)
 {
     CoroData* current{ nullptr };
     // be careful about attempted accesses in the final throes of app shutdown
@@ -94,7 +95,7 @@ LLCoros::coro::id LLCoros::get_self()
 //static
 void LLCoros::set_consuming(bool consuming)
 {
-    CoroData& data(get_CoroData("set_consuming()"));
+    auto& data(get_CoroData("set_consuming()"));
     // DO NOT call this on the main() coroutine.
     llassert_always(! data.mName.empty());
     data.mConsuming = consuming;
@@ -128,6 +129,15 @@ LLCoros::LLCoros():
     // points to it. So initialize it with a no-op deleter.
     mCurrent{ [](CoroData*){} }
 {
+    auto& llapp{ LLEventPumps::instance().obtain("LLApp") };
+    if (llapp.getListener("LLCoros") == LLBoundListener())
+    {
+        // chain our "LLCoros" pump onto "LLApp" pump: echo events posted to "LLApp"
+        mConn = llapp.listen(
+            "LLCoros",
+            [](const LLSD& event)
+            { return LLEventPumps::instance().obtain("LLCoros").post(event); });
+    }
 }
 
 LLCoros::~LLCoros()
@@ -177,26 +187,26 @@ std::string LLCoros::generateDistinctName(const std::string& prefix) const
     // Until we find an unused name, append a numeric suffix for uniqueness.
     while (CoroData::getInstance(name))
     {
-        name = STRINGIZE(prefix << unique++);
+        name = stringize(prefix, unique++);
     }
     return name;
 }
 
-/*==========================================================================*|
-bool LLCoros::kill(const std::string& name)
+bool LLCoros::killreq(const std::string& name)
 {
-    CoroMap::iterator found = mCoros.find(name);
-    if (found == mCoros.end())
+    auto found = CoroData::getInstance(name);
+    if (! found)
     {
         return false;
     }
-    // Because this is a boost::ptr_map, erasing the map entry also destroys
-    // the referenced heap object, in this case the boost::coroutine object,
-    // which will terminate the coroutine.
-    mCoros.erase(found);
+    // Next time the subject coroutine calls checkStop(), make it terminate.
+    found->mKilledBy = getName();
+    // But if it's waiting for something, notify anyone in a position to poke
+    // it.
+    LLEventPumps::instance().obtain("LLCoros").post(
+        llsd::map("status", "killreq", "coro", name));
     return true;
 }
-|*==========================================================================*/
 
 //static
 std::string LLCoros::getName()
@@ -207,7 +217,7 @@ std::string LLCoros::getName()
 //static
 std::string LLCoros::logname()
 {
-    LLCoros::CoroData& data(get_CoroData("logname()"));
+    auto& data(get_CoroData("logname()"));
     return data.mName.empty()? data.getKey() : data.mName;
 }
 
@@ -360,7 +370,7 @@ void LLCoros::toplevel(std::string name, callable_t callable)
         // Any uncaught exception derived from LLContinueError will be caught
         // here and logged. This coroutine will terminate but the rest of the
         // viewer will carry on.
-        LOG_UNHANDLED_EXCEPTION(STRINGIZE("coroutine " << name));
+        LOG_UNHANDLED_EXCEPTION(stringize("coroutine ", name));
     }
     catch (...)
     {
@@ -373,15 +383,24 @@ void LLCoros::toplevel(std::string name, callable_t callable)
 }
 
 //static
-void LLCoros::checkStop()
+void LLCoros::checkStop(callable_t cleanup)
 {
+    // don't replicate this 'if' test throughout the code below
+    if (! cleanup)
+    {
+        cleanup = {[](){}};         // hey, look, I'm coding in Haskell!
+    }
+
     if (wasDeleted())
     {
+        cleanup();
         LLTHROW(Shutdown("LLCoros was deleted"));
     }
-    // do this AFTER the check above, because getName() depends on
-    // get_CoroData(), which depends on the local_ptr in our instance().
-    if (getName().empty())
+
+    // do this AFTER the check above, because get_CoroData() depends on the
+    // local_ptr in our instance().
+    auto& data(get_CoroData("checkStop()"));
+    if (data.mName.empty())
     {
         // Our Stop exception and its subclasses are intended to stop loitering
         // coroutines. Don't throw it from the main coroutine.
@@ -389,19 +408,80 @@ void LLCoros::checkStop()
     }
     if (LLApp::isStopped())
     {
+        cleanup();
         LLTHROW(Stopped("viewer is stopped"));
     }
     if (! LLApp::isRunning())
     {
+        cleanup();
         LLTHROW(Stopping("viewer is stopping"));
     }
+    if (! data.mKilledBy.empty())
+    {
+        // Someone wants to kill this coroutine
+        cleanup();
+        LLTHROW(Killed(stringize("coroutine ", data.mName, " killed by ", data.mKilledBy)));
+    }
+}
+
+LLBoundListener LLCoros::getStopListener(const std::string& caller, LLVoidListener cleanup)
+{
+    if (! cleanup)
+        return {};
+
+    // This overload only responds to viewer shutdown.
+    return LLEventPumps::instance().obtain("LLCoros")
+        .listen(
+            LLEventPump::inventName(caller),
+            [cleanup](const LLSD& event)
+            {
+                auto status{ event["status"].asString() };
+                if (status != "running" && status != "killreq")
+                {
+                    cleanup(event);
+                }
+                return false;
+            });
+}
+
+LLBoundListener LLCoros::getStopListener(const std::string& caller,
+                                           const std::string& cnsmr,
+                                           LLVoidListener cleanup)
+{
+    if (! cleanup)
+        return {};
+
+    std::string consumer{cnsmr};
+    if (consumer.empty())
+    {
+        consumer = getName();
+    }
+
+    // This overload responds to viewer shutdown and to killreq(consumer).
+    return LLEventPumps::instance().obtain("LLCoros")
+        .listen(
+            LLEventPump::inventName(caller),
+            [consumer, cleanup](const LLSD& event)
+            {
+                auto status{ event["status"].asString() };
+                if (status == "killreq")
+                {
+                    if (event["coro"].asString() == consumer)
+                    {
+                        cleanup(event);
+                    }
+                }
+                else if (status != "running")
+                {
+                    cleanup(event);
+                }
+                return false;
+            });
 }
 
 LLCoros::CoroData::CoroData(const std::string& name):
     LLInstanceTracker<CoroData, std::string>(name),
     mName(name),
-    // don't consume events unless specifically directed
-    mConsuming(false),
     mCreationTime(LLTimer::getTotalSeconds())
 {
 }
@@ -414,7 +494,6 @@ LLCoros::CoroData::CoroData(int n):
     // empty string as its visible name because some consumers test for that.
     LLInstanceTracker<CoroData, std::string>("main" + stringize(n)),
     mName(),
-    mConsuming(false),
     mCreationTime(LLTimer::getTotalSeconds())
 {
 }