From 8a7f0001be88122256b1a8dc29b066210dc85625 Mon Sep 17 00:00:00 2001
From: Jonas Schnelli <dev@jonasschnelli.ch>
Date: Fri, 8 Jan 2016 11:03:52 +0100
Subject: [PATCH] [RPC] remove the option of having multiple timer interfaces

---
 src/httprpc.cpp       |  4 ++--
 src/qt/rpcconsole.cpp |  6 ++++--
 src/rpcserver.cpp     | 22 +++++++++++++---------
 src/rpcserver.h       | 10 ++++++----
 4 files changed, 25 insertions(+), 17 deletions(-)

diff --git a/src/httprpc.cpp b/src/httprpc.cpp
index 2920aa26f..1466dc0cb 100644
--- a/src/httprpc.cpp
+++ b/src/httprpc.cpp
@@ -226,7 +226,7 @@ bool StartHTTPRPC()
 
     assert(EventBase());
     httpRPCTimerInterface = new HTTPRPCTimerInterface(EventBase());
-    RPCRegisterTimerInterface(httpRPCTimerInterface);
+    RPCSetTimerInterface(httpRPCTimerInterface);
     return true;
 }
 
@@ -240,7 +240,7 @@ void StopHTTPRPC()
     LogPrint("rpc", "Stopping HTTP RPC server\n");
     UnregisterHTTPHandler("/", true);
     if (httpRPCTimerInterface) {
-        RPCUnregisterTimerInterface(httpRPCTimerInterface);
+        RPCUnsetTimerInterface(httpRPCTimerInterface);
         delete httpRPCTimerInterface;
         httpRPCTimerInterface = 0;
     }
diff --git a/src/qt/rpcconsole.cpp b/src/qt/rpcconsole.cpp
index 4c869b9ac..7178bc00e 100644
--- a/src/qt/rpcconsole.cpp
+++ b/src/qt/rpcconsole.cpp
@@ -278,7 +278,9 @@ RPCConsole::RPCConsole(const PlatformStyle *platformStyle, QWidget *parent) :
 #endif
     // Register RPC timer interface
     rpcTimerInterface = new QtRPCTimerInterface();
-    RPCRegisterTimerInterface(rpcTimerInterface);
+    // avoid accidentally overwriting an existing, non QTThread
+    // based timer interface
+    RPCSetTimerInterfaceIfUnset(rpcTimerInterface);
 
     startExecutor();
     setTrafficGraphRange(INITIAL_TRAFFIC_GRAPH_MINS);
@@ -293,7 +295,7 @@ RPCConsole::~RPCConsole()
 {
     GUIUtil::saveWindowGeometry("nRPCConsoleWindow", this);
     Q_EMIT stopExecutor();
-    RPCUnregisterTimerInterface(rpcTimerInterface);
+    RPCUnsetTimerInterface(rpcTimerInterface);
     delete rpcTimerInterface;
     delete ui;
 }
diff --git a/src/rpcserver.cpp b/src/rpcserver.cpp
index de60bb6b1..78d6898bc 100644
--- a/src/rpcserver.cpp
+++ b/src/rpcserver.cpp
@@ -33,7 +33,7 @@ static bool fRPCInWarmup = true;
 static std::string rpcWarmupStatus("RPC server started");
 static CCriticalSection cs_rpcWarmup;
 /* Timer-creating functions */
-static std::vector<RPCTimerInterface*> timerInterfaces;
+static RPCTimerInterface* timerInterface = NULL;
 /* Map of name to timer.
  * @note Can be changed to std::unique_ptr when C++11 */
 static std::map<std::string, boost::shared_ptr<RPCTimerBase> > deadlineTimers;
@@ -546,24 +546,28 @@ std::string HelpExampleRpc(const std::string& methodname, const std::string& arg
         "\"method\": \"" + methodname + "\", \"params\": [" + args + "] }' -H 'content-type: text/plain;' http://127.0.0.1:8332/\n";
 }
 
-void RPCRegisterTimerInterface(RPCTimerInterface *iface)
+void RPCSetTimerInterfaceIfUnset(RPCTimerInterface *iface)
 {
-    timerInterfaces.push_back(iface);
+    if (!timerInterface)
+        timerInterface = iface;
 }
 
-void RPCUnregisterTimerInterface(RPCTimerInterface *iface)
+void RPCSetTimerInterface(RPCTimerInterface *iface)
 {
-    std::vector<RPCTimerInterface*>::iterator i = std::find(timerInterfaces.begin(), timerInterfaces.end(), iface);
-    assert(i != timerInterfaces.end());
-    timerInterfaces.erase(i);
+    timerInterface = iface;
+}
+
+void RPCUnsetTimerInterface(RPCTimerInterface *iface)
+{
+    if (timerInterface == iface)
+        timerInterface = NULL;
 }
 
 void RPCRunLater(const std::string& name, boost::function<void(void)> func, int64_t nSeconds)
 {
-    if (timerInterfaces.empty())
+    if (!timerInterface)
         throw JSONRPCError(RPC_INTERNAL_ERROR, "No timer handler registered for RPC");
     deadlineTimers.erase(name);
-    RPCTimerInterface* timerInterface = timerInterfaces.back();
     LogPrint("rpc", "queue run of timer %s in %i seconds (using %s)\n", name, nSeconds, timerInterface->Name());
     deadlineTimers.insert(std::make_pair(name, boost::shared_ptr<RPCTimerBase>(timerInterface->NewTimer(func, nSeconds*1000))));
 }
diff --git a/src/rpcserver.h b/src/rpcserver.h
index f85ab42f0..9dce31887 100644
--- a/src/rpcserver.h
+++ b/src/rpcserver.h
@@ -100,10 +100,12 @@ public:
     virtual RPCTimerBase* NewTimer(boost::function<void(void)>& func, int64_t millis) = 0;
 };
 
-/** Register factory function for timers */
-void RPCRegisterTimerInterface(RPCTimerInterface *iface);
-/** Unregister factory function for timers */
-void RPCUnregisterTimerInterface(RPCTimerInterface *iface);
+/** Set the factory function for timers */
+void RPCSetTimerInterface(RPCTimerInterface *iface);
+/** Set the factory function for timer, but only, if unset */
+void RPCSetTimerInterfaceIfUnset(RPCTimerInterface *iface);
+/** Unset factory function for timers */
+void RPCUnsetTimerInterface(RPCTimerInterface *iface);
 
 /**
  * Run func nSeconds from now.