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+/*
+ * Copyright (c) 2017 Cisco and/or its affiliates.
+ * Licensed 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.
+ */
+
+#ifndef __VOM_RPC_CMD_H__
+#define __VOM_RPC_CMD_H__
+
+#include <future>
+
+#include "vom/cmd.hpp"
+#include "vom/logger.hpp"
+
+namespace VOM {
+/**
+ * A base class for all RPC commands to VPP.
+ * RPC commands are one of the sub-set of command types to VPP
+ * that modify/create state in VPP and thus return an error code.
+ * Commands are issued in one thread context, but read in another. The
+ * command has an associated std::promise that is met by the RX thread.
+ * this allows the sender, which waits on the promise's future, to
+ * experience a synchronous command.
+ *
+ * The command is templatised on the type of the HW::item to be set by
+ * the command, and the data returned in the promise,
+ */
+template <typename HWITEM, typename DATA, typename MSG>
+class rpc_cmd : public cmd
+{
+public:
+ /**
+ * convenient typedef
+ */
+ typedef MSG msg_t;
+
+ /**
+ * Constructor taking the HW item that will be updated by the command
+ */
+ rpc_cmd(HWITEM& item)
+ : cmd()
+ , m_hw_item(item)
+ , m_promise()
+ {
+ }
+
+ /**
+ * Desructor
+ */
+ virtual ~rpc_cmd() {}
+
+ /**
+ * return the HW item the command updates
+ */
+ HWITEM& item() { return m_hw_item; }
+
+ /**
+ * return the const HW item the command updates
+ */
+ const HWITEM& item() const { return m_hw_item; }
+
+ /**
+ * Fulfill the commands promise. Called from the RX thread
+ */
+ void fulfill(const DATA& d) { m_promise.set_value(d); }
+
+ /**
+ * Wait on the commands promise. i.e. block on the completion
+ * of the command.
+ */
+ DATA wait()
+ {
+ std::future_status status;
+ std::future<DATA> result;
+
+ result = m_promise.get_future();
+ status = result.wait_for(std::chrono::seconds(5));
+
+ if (status != std::future_status::ready) {
+ return (DATA(rc_t::TIMEOUT));
+ }
+
+ return (result.get());
+ }
+
+ /**
+ * Called by the HW Command Q when it is disabled to indicate the
+ * command can be considered successful without issuing it to HW
+ */
+ virtual void succeeded() { m_hw_item.set(rc_t::OK); }
+
+ /**
+ * call operator used as a callback by VAPI when the reply is available
+ */
+ virtual vapi_error_e operator()(MSG& reply)
+ {
+ int retval = reply.get_response().get_payload().retval;
+ VOM_LOG(log_level_t::DEBUG) << to_string() << " " << retval;
+ fulfill(rc_t::from_vpp_retval(retval));
+
+ return (VAPI_OK);
+ }
+
+ /**
+ * Retire/cancel a long running command
+ */
+ virtual void retire(connection& con) {}
+
+protected:
+ /**
+ * A reference to an object's HW::item that the command will update
+ */
+ HWITEM& m_hw_item;
+
+ /**
+ * The promise that implements the synchronous issue
+ */
+ std::promise<DATA> m_promise;
+};
+};
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "mozilla")
+ * End:
+ */
+
+#endif