From 5ca9b1a9c3dd1e04ecc4771239afc5d2a64ec2dd Mon Sep 17 00:00:00 2001
From: "Wladimir J. van der Laan" <laanwj@gmail.com>
Date: Fri, 8 Jan 2016 17:34:41 +0100
Subject: [PATCH] Merge pull request #7317

8a7f000 [RPC] remove the option of having multiple timer interfaces (Jonas Schnelli)
db198d5 Fix RPCTimerInterface ordering issue Dispatching a QThread from a non Qt thread is not allowed. Always use the HTTPRPCTimerInterface (non QT) to dispatch RPCRunLater threads. (Jonas Schnelli)
---
 src/httprpc.cpp       |  4 ++--
 src/qt/rpcconsole.cpp |  6 ++++--
 src/rpc/server.cpp    | 22 +++++++++++++---------
 src/rpc/server.h      | 10 ++++++----
 4 files changed, 25 insertions(+), 17 deletions(-)

diff --git a/src/httprpc.cpp b/src/httprpc.cpp
index ec370cc87..0ed0bbf4e 100644
--- a/src/httprpc.cpp
+++ b/src/httprpc.cpp
@@ -231,7 +231,7 @@ bool StartHTTPRPC()
 
     assert(EventBase());
     httpRPCTimerInterface = new HTTPRPCTimerInterface(EventBase());
-    RPCRegisterTimerInterface(httpRPCTimerInterface);
+    RPCSetTimerInterface(httpRPCTimerInterface);
     return true;
 }
 
@@ -245,7 +245,7 @@ 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 a3ee59532..db739485f 100644
--- a/src/qt/rpcconsole.cpp
+++ b/src/qt/rpcconsole.cpp
@@ -302,7 +302,9 @@ 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);
 
     setTrafficGraphRange(INITIAL_TRAFFIC_GRAPH_SETTING);
 
@@ -316,7 +318,7 @@ RPCConsole::RPCConsole(const PlatformStyle *platformStyle, QWidget *parent) :
 RPCConsole::~RPCConsole()
 {
     GUIUtil::saveWindowGeometry("nRPCConsoleWindow", this);
-    RPCUnregisterTimerInterface(rpcTimerInterface);
+    RPCUnsetTimerInterface(rpcTimerInterface);
     delete rpcTimerInterface;
     delete ui;
 }
diff --git a/src/rpc/server.cpp b/src/rpc/server.cpp
index 86e36373a..1763e20d0 100644
--- a/src/rpc/server.cpp
+++ b/src/rpc/server.cpp
@@ -34,7 +34,7 @@ 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;
@@ -589,24 +589,28 @@ std::string HelpExampleRpc(const std::string& methodname, const std::string& arg
         "\"method\": \"" + methodname + "\", \"params\": [" + args + "] }' -H 'content-type: text/plain;' http://127.0.0.1:9998/\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/rpc/server.h b/src/rpc/server.h
index 9c9fa7729..54bda9187 100644
--- a/src/rpc/server.h
+++ b/src/rpc/server.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.