SL-19690: Follow up on Rye Mutt's fix for shutdown crashes.

Rather than continuing to propagate try/catch (Closed)
(aka LLThreadSafeQueueInterrupt) constructs through the code base, make
WorkQueueBase::post() return bool indicating success (i.e. ! isClosed()).
This obviates postIfOpen(), which no one was using anyway.

In effect, postIfOpen() is renamed post(), bypassing the exception when
isClosed().

Review existing try/catch blocks of that sort, changing to test for post()
returning false.

1 files changed, 29 insertions, 32 deletions

diff --git a/indra/llaudio/llaudiodecodemgr.cpp b/indra/llaudio/llaudiodecodemgr.cpp
index 38a6b41afe..190c5290cb 100755
--- a/indra/llaudio/llaudiodecodemgr.cpp
+++ b/indra/llaudio/llaudiodecodemgr.cpp
@@ -607,40 +607,37 @@ void LLAudioDecodeMgr::Impl::startMoreDecodes()
 
         // Kick off a decode
         mDecodes[decode_id] = LLPointer<LLVorbisDecodeState>(NULL);
-        try
-        {
-            main_queue->postTo(
-                general_queue,
-                [decode_id]() // Work done on general queue
-                {
-                    LLPointer<LLVorbisDecodeState> decode_state = beginDecodingAndWritingAudio(decode_id);
-
-                    if (!decode_state)
-                    {
-                        // Audio decode has errored
-                        return decode_state;
-                    }
+        bool posted = main_queue->postTo(
+            general_queue,
+            [decode_id]() // Work done on general queue
+            {
+                LLPointer<LLVorbisDecodeState> decode_state = beginDecodingAndWritingAudio(decode_id);
 
-                    // Disk write of decoded audio is now in progress off-thread
+                if (!decode_state)
+                {
+                    // Audio decode has errored
                     return decode_state;
-                },
-                [decode_id, this](LLPointer<LLVorbisDecodeState> decode_state) // Callback to main thread
-                mutable {
-                    if (!gAudiop)
-                    {
-                        // There is no LLAudioEngine anymore. This might happen if
-                        // an audio decode is enqueued just before shutdown.
-                        return;
-                    }
-
-                    // At this point, we can be certain that the pointer to "this"
-                    // is valid because the lifetime of "this" is dependent upon
-                    // the lifetime of gAudiop.
-
-                    enqueueFinishAudio(decode_id, decode_state);
-                });
-        }
-        catch (const LLThreadSafeQueueInterrupt&)
+                }
+
+                // Disk write of decoded audio is now in progress off-thread
+                return decode_state;
+            },
+            [decode_id, this](LLPointer<LLVorbisDecodeState> decode_state) // Callback to main thread
+            mutable {
+                if (!gAudiop)
+                {
+                    // There is no LLAudioEngine anymore. This might happen if
+                    // an audio decode is enqueued just before shutdown.
+                    return;
+                }
+
+                // At this point, we can be certain that the pointer to "this"
+                // is valid because the lifetime of "this" is dependent upon
+                // the lifetime of gAudiop.
+
+                enqueueFinishAudio(decode_id, decode_state);
+            });
+        if (! posted)
         {
             // Shutdown
             // Consider making processQueue() do a cleanup instead