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-rw-r--r-- | sca-cpp/branches/lightweight-sca/components/cache/datacache.cpp | 129 |
1 files changed, 129 insertions, 0 deletions
diff --git a/sca-cpp/branches/lightweight-sca/components/cache/datacache.cpp b/sca-cpp/branches/lightweight-sca/components/cache/datacache.cpp new file mode 100644 index 0000000000..c259ec33c6 --- /dev/null +++ b/sca-cpp/branches/lightweight-sca/components/cache/datacache.cpp @@ -0,0 +1,129 @@ +/* + * 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 data cache component implementation which coordinates access to two + * levels of backend read/write caches or stores. Each cache or store is + * accessed through two references: a writer reference and a reader reference. + * + * This is useful if your level2 store is made of a master and slave + * replicated databases, you can then wire the writer reference to the master + * database and the reader reference to one your slave databases (assuming + * that the updates eventually get replicated to the slave database, in the + * meantime the updates will be retrieved from the level1 cache). + */ + +#define WANT_HTTPD_LOG 1 +#include "string.hpp" +#include "function.hpp" +#include "list.hpp" +#include "value.hpp" +#include "monad.hpp" + +namespace tuscany { +namespace datacache { + +/** + * Get an item from the cache. + */ +const failable<value> get(const value& key, const lambda<value(const list<value>&)>& rcache1, const lambda<value(const list<value>&)>& wcache1, const lambda<value(const list<value>&)>& rcache2, unused const lambda<value(const list<value>&)>& wcache2) { + + // Lookup level1 cache + const value val1 = rcache1(mklist<value>("get", key)); + if (!isNil(val1)) + return val1; + + // Lookup level2 cache + const value val2 = rcache2(mklist<value>("get", key)); + if (isNil(val2)) { + ostringstream os; + os << "Couldn't get cache entry: " << key; + return mkfailure<value>(str(os), 404, false); + } + + // Update level1 cache + wcache1(mklist<value>("put", key, val2)); + + return val2; +} + +/** + * Post an item to the cache. + */ +const failable<value> post(const value& key, const value& val, unused const lambda<value(const list<value>&)>& rcache1, const lambda<value(const list<value>&)>& wcache1, unused const lambda<value(const list<value>&)>& rcache2, const lambda<value(const list<value>&)>& wcache2) { + const value id = append<value>(key, mklist(mkuuid())); + + // Update level1 cache + wcache1(mklist<value>("put", id, val)); + + // Update level2 cache + wcache2(mklist<value>("put", id, val)); + + return id; +} + +/** + * Put an item into the cache. + */ +const failable<value> put(const value& key, const value& val, unused const lambda<value(const list<value>&)>& rcache1, const lambda<value(const list<value>&)>& wcache1, unused const lambda<value(const list<value>&)>& rcache2, const lambda<value(const list<value>&)>& wcache2) { + + // Update level1 cache + wcache1(mklist<value>("put", key, val)); + + // Update level2 cache + wcache2(mklist<value>("put", key, val)); + + return value(true); +} + +/** + * Delete an item from the cache. + */ +const failable<value> del(const value& key, unused const lambda<value(const list<value>&)>& rcache1, const lambda<value(const list<value>&)>& wcache1, unused const lambda<value(const list<value>&)>& rcache2, const lambda<value(const list<value>&)>& wcache2) { + + // Delete from level1 cache + wcache1(mklist<value>("delete", key)); + + // Delete from level2 cache + wcache2(mklist<value>("delete", key)); + + return value(true); +} + +} +} + +extern "C" { + +const tuscany::value apply(const tuscany::list<tuscany::value>& params) { + const tuscany::value func(car(params)); + if (func == "get") + return tuscany::datacache::get(cadr(params), caddr(params), cadddr(params), caddddr(params), cadddddr(params)); + if (func == "post") + return tuscany::datacache::post(cadr(params), caddr(params), cadddr(params), caddddr(params), cadddddr(params), caddddddr(params)); + if (func == "put") + return tuscany::datacache::put(cadr(params), caddr(params), cadddr(params), caddddr(params), cadddddr(params), caddddddr(params)); + if (func == "delete") + return tuscany::datacache::del(cadr(params), caddr(params), cadddr(params), caddddr(params), cadddddr(params)); + return tuscany::mkfailure<tuscany::value>(); +} + +} |