From 5f4adbf1a3a40632d5d471e9acccd058220de0a5 Mon Sep 17 00:00:00 2001
From: Pavel Kirienko <pavel.kirienko@gmail.com>
Date: Sat, 23 May 2015 00:38:17 +0300
Subject: [PATCH] dynamic_node_id_server::distributed::StateReport structure

---
 .../distributed/raft_core.hpp                 | 25 +++++---
 .../distributed/server.hpp                    | 62 +++++++++++++++++++
 .../node_discoverer.hpp                       |  6 ++
 3 files changed, 86 insertions(+), 7 deletions(-)

diff --git a/libuavcan/include/uavcan/protocol/dynamic_node_id_server/distributed/raft_core.hpp b/libuavcan/include/uavcan/protocol/dynamic_node_id_server/distributed/raft_core.hpp
index b77dfadf9e..ab26635bbe 100644
--- a/libuavcan/include/uavcan/protocol/dynamic_node_id_server/distributed/raft_core.hpp
+++ b/libuavcan/include/uavcan/protocol/dynamic_node_id_server/distributed/raft_core.hpp
@@ -74,6 +74,15 @@ public:
  */
 class RaftCore : private TimerBase
 {
+public:
+    enum ServerState
+    {
+        ServerStateFollower,
+        ServerStateCandidate,
+        ServerStateLeader
+    };
+
+private:
     typedef MethodBinder<RaftCore*, void (RaftCore::*)(const ReceivedDataStructure<AppendEntries::Request>&,
                                                        ServiceResponseDataStructure<AppendEntries::Response>&)>
         AppendEntriesCallback;
@@ -88,13 +97,6 @@ class RaftCore : private TimerBase
     typedef MethodBinder<RaftCore*, void (RaftCore::*)(const ServiceCallResult<RequestVote>&)>
         RequestVoteResponseCallback;
 
-    enum ServerState
-    {
-        ServerStateFollower,
-        ServerStateCandidate,
-        ServerStateLeader
-    };
-
     struct PendingAppendEntriesFields
     {
         Log::Index prev_log_index;
@@ -895,6 +897,15 @@ public:
         // Remember that index zero contains a special-purpose entry that doesn't count as allocation
         return persistent_state_.getLog().getLastIndex();
     }
+
+    /**
+     * These accessors are needed for debugging, visualization and testing.
+     */
+    const PersistentState& getPersistentState() const { return persistent_state_; }
+    const ClusterManager& getClusterManager()   const { return cluster_; }
+    MonotonicTime getLastActivityTimestamp()    const { return last_activity_timestamp_; }
+    bool isInActiveMode()                       const { return active_mode_; }
+    ServerState getServerState()                const { return server_state_; }
 };
 
 }
diff --git a/libuavcan/include/uavcan/protocol/dynamic_node_id_server/distributed/server.hpp b/libuavcan/include/uavcan/protocol/dynamic_node_id_server/distributed/server.hpp
index 2fd6e2158a..940529e358 100644
--- a/libuavcan/include/uavcan/protocol/dynamic_node_id_server/distributed/server.hpp
+++ b/libuavcan/include/uavcan/protocol/dynamic_node_id_server/distributed/server.hpp
@@ -295,6 +295,68 @@ public:
     }
 
     Log::Index getNumAllocations() const { return raft_core_.getNumAllocations(); }
+
+    /**
+     * These accessors are needed for debugging, visualization and testing.
+     */
+    const RaftCore& getRaftCore() const { return raft_core_; }
+    const NodeDiscoverer& getNodeDiscoverer() const { return node_discoverer_; }
+};
+
+/**
+ * This structure represents immediate state of the server.
+ * It can be used for state visualization and debugging.
+ */
+struct StateReport
+{
+    uint8_t cluster_size;
+
+    RaftCore::ServerState state;
+    bool is_active;
+
+    Log::Index last_log_index;
+    Log::Index commit_index;
+
+    Term last_log_term;
+    Term current_term;
+
+    NodeID voted_for;
+
+    MonotonicTime last_activity_timestamp;
+
+    uint8_t num_unknown_nodes;
+
+    struct FollowerState
+    {
+        NodeID node_id;
+        Log::Index next_index;
+        Log::Index match_index;
+
+        FollowerState()
+            : next_index(0)
+            , match_index(0)
+        { }
+    } followers[ClusterManager::MaxClusterSize - 1];
+
+    StateReport(const Server& s)
+        : cluster_size           (s.getRaftCore().getClusterManager().getClusterSize())
+        , state                  (s.getRaftCore().getServerState())
+        , is_active              (s.getRaftCore().isInActiveMode())
+        , last_log_index         (s.getRaftCore().getPersistentState().getLog().getLastIndex())
+        , commit_index           (s.getRaftCore().getCommitIndex())
+        , last_log_term          (0)    // See below
+        , current_term           (s.getRaftCore().getPersistentState().getCurrentTerm())
+        , voted_for              (s.getRaftCore().getPersistentState().getVotedFor())
+        , last_activity_timestamp(s.getRaftCore().getLastActivityTimestamp())
+        , num_unknown_nodes      (s.getNodeDiscoverer().getNumUnknownNodes())
+    {
+        const Entry* const e = s.getRaftCore().getPersistentState().getLog().getEntryAtIndex(last_log_index);
+        UAVCAN_ASSERT(e != NULL);
+        if (e != NULL)
+        {
+            last_log_term = e->term;
+        }
+    }
 };
 
 }
diff --git a/libuavcan/include/uavcan/protocol/dynamic_node_id_server/node_discoverer.hpp b/libuavcan/include/uavcan/protocol/dynamic_node_id_server/node_discoverer.hpp
index 03b4145759..d8042074a2 100644
--- a/libuavcan/include/uavcan/protocol/dynamic_node_id_server/node_discoverer.hpp
+++ b/libuavcan/include/uavcan/protocol/dynamic_node_id_server/node_discoverer.hpp
@@ -361,6 +361,12 @@ public:
      * Returns true if there's at least one node with pending GetNodeInfo.
      */
     bool hasUnknownNodes() const { return !node_map_.isEmpty(); }
+
+    /**
+     * Returns number of nodes that are being queried at the moment.
+     * This method is needed for testing and state visualization.
+     */
+    uint8_t getNumUnknownNodes() const { return static_cast<uint8_t>(node_map_.getSize()); }
 };
 
 }