From c9bfccc35345ce58fb5774d4b0b6a9868b262c0a Mon Sep 17 00:00:00 2001
From: giorgio <giorgio@13f79535-47bb-0310-9956-ffa450edef68>
Date: Wed, 5 Sep 2012 08:31:30 +0000
Subject: git-svn-id: http://svn.us.apache.org/repos/asf/tuscany@1381061
 13f79535-47bb-0310-9956-ffa450edef68

---
 .../components/queue/queue-listener.cpp            | 159 +++++++++++++++++++++
 1 file changed, 159 insertions(+)
 create mode 100644 sca-cpp/branches/lightweight-sca/components/queue/queue-listener.cpp

(limited to 'sca-cpp/branches/lightweight-sca/components/queue/queue-listener.cpp')

diff --git a/sca-cpp/branches/lightweight-sca/components/queue/queue-listener.cpp b/sca-cpp/branches/lightweight-sca/components/queue/queue-listener.cpp
new file mode 100644
index 0000000000..483d0de65a
--- /dev/null
+++ b/sca-cpp/branches/lightweight-sca/components/queue/queue-listener.cpp
@@ -0,0 +1,159 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/* $Rev$ $Date$ */
+
+/**
+ * AMQP queue listener component implementation.
+ */
+
+#define WANT_HTTPD_LOG 1
+#include "string.hpp"
+#include "function.hpp"
+#include "list.hpp"
+#include "value.hpp"
+#include "monad.hpp"
+#include "parallel.hpp"
+#include "qpid.hpp"
+
+// Ignore conversion issues and redundant declarations in Qpid headers
+#ifdef WANT_MAINTAINER_WARNINGS
+#pragma GCC diagnostic ignored "-Wconversion"
+#pragma GCC diagnostic ignored "-Wredundant-decls"
+#endif
+
+namespace tuscany {
+namespace queue {
+
+/**
+ * A relay function that posts the AMQP messages it receives to a relay component reference.
+ */
+class relay {
+public:
+    relay(const lambda<value(const list<value>&)>& rel) : rel(rel) {
+    }
+
+    const bool operator()(const value& k, const value& v) const {
+        debug(k, "queue::relay::key");
+        debug(v, "queue::relay::value");
+        const value res = rel(mklist<value>("post", isList(k)? (list<value>)k : mklist<value>(k), v));
+        return true;
+    }
+
+private:
+    const lambda<value(const list<value>&)> rel;
+};
+
+/**
+ * Subscribe and listen to an AMQP queue.
+ */
+class subscribe {
+public:
+    subscribe(const string& qname, const lambda<bool(const value&, const value&)>& l, const QpidSubscription& qsub) : qname(qname), l(l), qsub(qsub) {
+    }
+
+    const failable<bool> operator()() const {
+        gc_pool pool;
+        debug(qname, "queue::subscribe::listen");
+        const failable<bool> r =  listen(qname, l, const_cast<QpidSubscription&>(qsub));
+        debug(qname, "queue::subscribe::stopped");
+        return r;
+    }
+
+private:
+    const string qname;
+    const lambda<bool(const value&, const value&)> l;
+    const QpidSubscription qsub;
+};
+
+/**
+ * Listener lambda function, responsible for starting an AMQP subscription in a worker thread, and
+ * apply any function calls to the listener component. The only supported function is stop(),
+ * called to stop the listener component and shutdown the worker thread.
+ */
+class listener {
+public:
+    listener(QpidConnection& qc, QpidSession& qs, QpidSubscription& qsub, worker& w) : qc(qc), qs(qs), qsub(qsub), w(w) {
+    }
+
+    const value operator()(const list<value>& params) const {
+        const tuscany::value func(car(params));
+
+        // Stop the component
+        if (func != "stop")
+            return mkfailure<value>();
+        debug("queue::listener::stop");
+
+        // TODO check why stop() and close() hang in child processes
+        stop(const_cast<QpidSubscription&>(qsub));
+        close(const_cast<QpidSession&>(qs));
+        close(const_cast<QpidConnection&>(qc));
+        cancel(const_cast<worker&>(w));
+
+        debug("queue::listener::stopped");
+        return failable<value>(value(lambda<value(const list<value>&)>()));
+    }
+
+private:
+    QpidConnection qc;
+    QpidSession qs;
+    QpidSubscription qsub;
+    worker w;
+};
+
+/**
+ * Start the component.
+ */
+const failable<value> start(const list<value>& params) {
+    // Extract the relay reference and the AMQP key and queue name
+    const value rel = car(params);
+    const value pk = ((lambda<value(const list<value>&)>)cadr(params))(list<value>());
+    const value key = isList(pk)? (list<value>)pk : mklist<value>(pk);
+    const value qname = ((lambda<value(const list<value>&)>)caddr(params))(list<value>());
+
+    // Create an AMQP session
+    QpidConnection qc(false);
+    QpidSession qs(qc, false);
+
+    // Declare the configured AMQP key / queue pair
+    declareQueue(key, qname, qs);
+
+    // Listen and relay messages in a worker thread
+    QpidSubscription qsub(qs, false);
+    worker w(3);
+    const lambda<bool(const value&, const value&)> rl = relay(rel);
+    submit<failable<bool> >(w, lambda<failable<bool>()>(subscribe(qname, rl, qsub)));
+
+    // Return the listener component lambda function
+    return value(lambda<value(const list<value>&)>(listener(qc, qs, qsub, w)));
+}
+
+}
+}
+
+extern "C" {
+
+const tuscany::value apply(const tuscany::list<tuscany::value>& params) {
+    const tuscany::value func(car(params));
+    if (func == "start")
+        return tuscany::queue::start(cdr(params));
+    return tuscany::mkfailure<tuscany::value>();
+}
+
+}
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