VPP Object Model (VOM)

The VOM is a C++ library for use by clients/agents of VPP for programming
state. It uses the binary APIs to do so. Various other common client side
functions are also provided. Please see om.hpp for a more detailed description.

Change-Id: Ib756bfe99817093815a9e26ccf464aa5583fc523
Signed-off-by: Neale Ranns <neale.ranns@cisco.com>
Co-authored-by: Mohsin Kazmi <sykazmi@cisco.com>

1 files changed, 139 insertions, 0 deletions

diff --git a/src/vpp-api/vom/rpc_cmd.hpp b/src/vpp-api/vom/rpc_cmd.hpp
new file mode 100644
index 00000000000..60dbd47c8b3
--- /dev/null
+++ b/src/vpp-api/vom/rpc_cmd.hpp
@@ -0,0 +1,139 @@
+/*
+ * 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