1 files changed, 32 insertions, 0 deletions
diff --git a/indra/newview/scripts/lua/ErrorQueue.lua b/indra/newview/scripts/lua/ErrorQueue.lua
new file mode 100644
index 0000000000..e6279f8411
--- /dev/null
+++ b/indra/newview/scripts/lua/ErrorQueue.lua
@@ -0,0 +1,32 @@
+-- ErrorQueue isa WaitQueue with the added feature that a producer can push an
+-- error through the queue. When that error is dequeued, the consumer will
+-- throw that error.
+
+local WaitQueue = require('WaitQueue')
+
+ErrorQueue = WaitQueue:new()
+
+function ErrorQueue:Enqueue(value)
+    -- normal value, not error
+    WaitQueue:Enqueue({ false, value })
+end
+
+function ErrorQueue:Error(message)
+    -- flag this entry as an error message
+    WaitQueue:Enqueue({ true, message })
+end
+
+function ErrorQueue:Dequeue()
+    local errflag, value = table.unpack(WaitQueue:Dequeue())
+    if errflag == nil then
+        -- queue has been closed, tell caller
+        return nil
+    end
+    if errflag then
+        -- 'value' is a message pushed by Error()
+        error(value)
+    end
+    return value
+end
+
+return ErrorQueue