Remove use of CRPCTable::appendCommand in wallet code

This commit does not change behavior.

2 files changed, 61 insertions, 31 deletions

diff --git a/src/rpc/server.cpp b/src/rpc/server.cpp
index cd90573da0..e803fabcc6 100644
--- a/src/rpc/server.cpp
+++ b/src/rpc/server.cpp
@@ -30,6 +30,7 @@ static std::string rpcWarmupStatus GUARDED_BY(cs_rpcWarmup) = "RPC server starte
 static RPCTimerInterface* timerInterface = nullptr;
 /* Map of name to timer. */
 static std::map<std::string, std::unique_ptr<RPCTimerBase> > deadlineTimers;
+static bool ExecuteCommand(const CRPCCommand& command, const JSONRPCRequest& request, UniValue& result, bool last_handler);
 
 struct RPCCommandExecutionInfo
 {
@@ -173,11 +174,11 @@ std::string CRPCTable::help(const std::string& strCommand, const JSONRPCRequest&
 {
     std::string strRet;
     std::string category;
-    std::set<rpcfn_type> setDone;
+    std::set<intptr_t> setDone;
     std::vector<std::pair<std::string, const CRPCCommand*> > vCommands;
 
     for (const auto& entry : mapCommands)
-        vCommands.push_back(make_pair(entry.second->category + entry.first, entry.second));
+        vCommands.push_back(make_pair(entry.second.front()->category + entry.first, entry.second.front()));
     sort(vCommands.begin(), vCommands.end());
 
     JSONRPCRequest jreq(helpreq);
@@ -193,9 +194,9 @@ std::string CRPCTable::help(const std::string& strCommand, const JSONRPCRequest&
         jreq.strMethod = strMethod;
         try
         {
-            rpcfn_type pfn = pcmd->actor;
-            if (setDone.insert(pfn).second)
-                (*pfn)(jreq);
+            UniValue unused_result;
+            if (setDone.insert(pcmd->unique_id).second)
+                pcmd->actor(jreq, unused_result, true /* last_handler */);
         }
         catch (const std::exception& e)
         {
@@ -337,32 +338,32 @@ CRPCTable::CRPCTable()
         const CRPCCommand *pcmd;
 
         pcmd = &vRPCCommands[vcidx];
-        mapCommands[pcmd->name] = pcmd;
+        mapCommands[pcmd->name].push_back(pcmd);
     }
 }
 
-const CRPCCommand *CRPCTable::operator[](const std::string &name) const
-{
-    std::map<std::string, const CRPCCommand*>::const_iterator it = mapCommands.find(name);
-    if (it == mapCommands.end())
-        return nullptr;
-    return (*it).second;
-}
-
 bool CRPCTable::appendCommand(const std::string& name, const CRPCCommand* pcmd)
 {
     if (IsRPCRunning())
         return false;
 
-    // don't allow overwriting for now
-    std::map<std::string, const CRPCCommand*>::const_iterator it = mapCommands.find(name);
-    if (it != mapCommands.end())
-        return false;
-
-    mapCommands[name] = pcmd;
+    mapCommands[name].push_back(pcmd);
     return true;
 }
 
+bool CRPCTable::removeCommand(const std::string& name, const CRPCCommand* pcmd)
+{
+    auto it = mapCommands.find(name);
+    if (it != mapCommands.end()) {
+        auto new_end = std::remove(it->second.begin(), it->second.end(), pcmd);
+        if (it->second.end() != new_end) {
+            it->second.erase(new_end, it->second.end());
+            return true;
+        }
+    }
+    return false;
+}
+
 void StartRPC()
 {
     LogPrint(BCLog::RPC, "Starting RPC\n");
@@ -543,18 +544,28 @@ UniValue CRPCTable::execute(const JSONRPCRequest &request) const
     }
 
     // Find method
-    const CRPCCommand *pcmd = tableRPC[request.strMethod];
-    if (!pcmd)
-        throw JSONRPCError(RPC_METHOD_NOT_FOUND, "Method not found");
+    auto it = mapCommands.find(request.strMethod);
+    if (it != mapCommands.end()) {
+        UniValue result;
+        for (const auto& command : it->second) {
+            if (ExecuteCommand(*command, request, result, &command == &it->second.back())) {
+                return result;
+            }
+        }
+    }
+    throw JSONRPCError(RPC_METHOD_NOT_FOUND, "Method not found");
+}
 
+static bool ExecuteCommand(const CRPCCommand& command, const JSONRPCRequest& request, UniValue& result, bool last_handler)
+{
     try
     {
         RPCCommandExecution execution(request.strMethod);
         // Execute, convert arguments to array if necessary
         if (request.params.isObject()) {
-            return pcmd->actor(transformNamedArguments(request, pcmd->argNames));
+            return command.actor(transformNamedArguments(request, command.argNames), result, last_handler);
         } else {
-            return pcmd->actor(request);
+            return command.actor(request, result, last_handler);
         }
     }
     catch (const std::exception& e)
diff --git a/src/rpc/server.h b/src/rpc/server.h
index 2d62a76f3c..e2a85887ba 100644
--- a/src/rpc/server.h
+++ b/src/rpc/server.h
@@ -131,10 +131,31 @@ typedef UniValue(*rpcfn_type)(const JSONRPCRequest& jsonRequest);
 class CRPCCommand
 {
 public:
+    //! RPC method handler reading request and assigning result. Should return
+    //! true if request is fully handled, false if it should be passed on to
+    //! subsequent handlers.
+    using Actor = std::function<bool(const JSONRPCRequest& request, UniValue& result, bool last_handler)>;
+
+    //! Constructor taking Actor callback supporting multiple handlers.
+    CRPCCommand(std::string category, std::string name, Actor actor, std::vector<std::string> args, intptr_t unique_id)
+        : category(std::move(category)), name(std::move(name)), actor(std::move(actor)), argNames(std::move(args)),
+          unique_id(unique_id)
+    {
+    }
+
+    //! Simplified constructor taking plain rpcfn_type function pointer.
+    CRPCCommand(const char* category, const char* name, rpcfn_type fn, std::initializer_list<const char*> args)
+        : CRPCCommand(category, name,
+                      [fn](const JSONRPCRequest& request, UniValue& result, bool) { result = fn(request); return true; },
+                      {args.begin(), args.end()}, intptr_t(fn))
+    {
+    }
+
     std::string category;
     std::string name;
-    rpcfn_type actor;
+    Actor actor;
     std::vector<std::string> argNames;
+    intptr_t unique_id;
 };
 
 /**
@@ -143,10 +164,9 @@ public:
 class CRPCTable
 {
 private:
-    std::map<std::string, const CRPCCommand*> mapCommands;
+    std::map<std::string, std::vector<const CRPCCommand*>> mapCommands;
 public:
     CRPCTable();
-    const CRPCCommand* operator[](const std::string& name) const;
     std::string help(const std::string& name, const JSONRPCRequest& helpreq) const;
 
     /**
@@ -169,9 +189,7 @@ public:
      *
      * Returns false if RPC server is already running (dump concurrency protection).
      *
-     * Commands cannot be overwritten (returns false).
-     *
-     * Commands with different method names but the same callback function will
+     * Commands with different method names but the same unique_id will
      * be considered aliases, and only the first registered method name will
      * show up in the help text command listing. Aliased commands do not have
      * to have the same behavior. Server and client code can distinguish
@@ -179,6 +197,7 @@ public:
      * register different names, types, and numbers of parameters.
      */
     bool appendCommand(const std::string& name, const CRPCCommand* pcmd);
+    bool removeCommand(const std::string& name, const CRPCCommand* pcmd);
 };
 
 bool IsDeprecatedRPCEnabled(const std::string& method);