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

---
 .../lightweight-sca/components/cache/memocache.cpp | 78 ++++++++++++++++++++++
 1 file changed, 78 insertions(+)
 create mode 100644 sca-cpp/branches/lightweight-sca/components/cache/memocache.cpp

(limited to 'sca-cpp/branches/lightweight-sca/components/cache/memocache.cpp')

diff --git a/sca-cpp/branches/lightweight-sca/components/cache/memocache.cpp b/sca-cpp/branches/lightweight-sca/components/cache/memocache.cpp
new file mode 100644
index 0000000000..e7e52cdc59
--- /dev/null
+++ b/sca-cpp/branches/lightweight-sca/components/cache/memocache.cpp
@@ -0,0 +1,78 @@
+/*
+ * 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.
+ */
+
+/* $Rev$ $Date$ */
+
+/**
+ * A cache component implementation which memoizes the value of function
+ * applications, keyed by the function arguments, in a key/value cache passed
+ * as a reference.
+ *
+ * This is useful if your functions are idempotent and applied many times to
+ * the same arguments. The results can then be retrieved quickly from the
+ * cache without actually applying the function.
+ */
+
+#define WANT_HTTPD_LOG 1
+#include "string.hpp"
+#include "function.hpp"
+#include "list.hpp"
+#include "value.hpp"
+#include "monad.hpp"
+
+namespace tuscany {
+namespace memocache {
+
+/**
+ * Memoize the value of a function application in a cache.
+ */
+const failable<value> memoize(const list<value>& params, const lambda<value(const list<value>&)>& relay, const lambda<value(const list<value>&)>& cache) {
+    debug(params, "memocache::memoize::params");
+
+    // Lookup memoized value from cache
+    const value val = cache(mklist<value>("get", params));
+    if (!isNil(val)) {
+        debug(val, "memocache::memoize::cached");
+        return val;
+    }
+
+    // Apply the given function
+    const value res = relay(params);
+    debug(res, "memocache::memoize::res");
+
+    // Store the result value in the cache
+    cache(mklist<value>("put", params, res));
+
+    return res;
+}
+
+}
+}
+
+extern "C" {
+
+const tuscany::value apply(const tuscany::list<tuscany::value>& params) {
+    const tuscany::value func(car(params));
+    if (func == "start" || func == "stop")
+        return tuscany::mkfailure<tuscany::value>();
+    const tuscany::list<tuscany::value> rev = tuscany::reverse(params);
+    return tuscany::memocache::memoize(tuscany::reverse(tuscany::cddr(rev)), tuscany::cadr(rev), tuscany::car(rev));
+}
+
+}
-- 
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