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-rw-r--r--teal-src/util/smqueue.tl99
1 files changed, 99 insertions, 0 deletions
diff --git a/teal-src/util/smqueue.tl b/teal-src/util/smqueue.tl
new file mode 100644
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--- /dev/null
+++ b/teal-src/util/smqueue.tl
@@ -0,0 +1,99 @@
+local queue = require "util.queue";
+
+local record lib
+ -- T would typically be util.stanza
+ record smqueue<T>
+ _queue : queue.queue<T>
+ _head : integer
+ _tail : integer
+
+ enum ack_errors
+ "tail"
+ "head"
+ "pop"
+ end
+ push : function (smqueue, T)
+ ack : function (smqueue, integer) : { T }, ack_errors
+ resumable : function (smqueue<T>) : boolean
+ resume : function (smqueue<T>) : queue.queue.iterator, any, integer
+ type consume_iter = function (smqueue<T>) : T
+ consume : function (smqueue<T>) : consume_iter
+
+ table : function (smqueue<T>) : { T }
+ end
+ new : function <T>(integer) : smqueue<T>
+end
+
+local type smqueue = lib.smqueue;
+
+function smqueue:push(v)
+ self._head = self._head + 1;
+ -- Wraps instead of errors
+ assert(self._queue:push(v));
+end
+
+function smqueue:ack(h : integer) : { any }, smqueue.ack_errors
+ if h < self._tail then
+ return nil, "tail";
+ elseif h > self._head then
+ return nil, "head";
+ end
+ -- TODO optimize? cache table fields
+ local acked = {};
+ self._tail = h;
+ local expect = self._head - self._tail;
+ while expect < self._queue:count() do
+ local v = self._queue:pop();
+ if not v then return nil, "pop"; end
+ table.insert(acked, v);
+ end
+ return acked;
+end
+
+function smqueue:count_unacked() : integer
+ return self._head - self._tail;
+end
+
+function smqueue:count_acked() : integer
+ return self._tail;
+end
+
+function smqueue:resumable() : boolean
+ return self._queue:count() >= (self._head - self._tail);
+end
+
+function smqueue:resume() : queue.queue.iterator, any, integer
+ return self._queue:items();
+end
+
+function smqueue:consume() : queue.queue.consume_iter
+ return self._queue:consume()
+end
+
+-- Compatibility layer, plain ol' table
+function smqueue:table() : { any }
+ local t : { any } = {};
+ for i, v in self:resume() do
+ t[i] = v;
+ end
+ return t;
+end
+
+local function freeze(q : smqueue<any>) : { string:integer }
+ return { head = q._head, tail = q._tail }
+end
+
+local queue_mt = {
+ --
+ __name = "smqueue";
+ __index = smqueue;
+ __len = smqueue.count_unacked;
+ __freeze = freeze;
+}
+
+function lib.new<T>(size : integer) : queue.queue<T>
+ assert(size>0);
+ return setmetatable({ _head = 0; _tail = 0; _queue = queue.new(size, true) }, queue_mt);
+end
+
+return lib;