From 58eef4b27d1075120994daf381d121ab7564332d Mon Sep 17 00:00:00 2001
From: Don Gagne <don@thegagnes.com>
Date: Tue, 9 Dec 2014 18:15:57 -0800
Subject: [PATCH] Fix create/destroy ordering problems between LinkManager and
 MAVLinkProtocol

---
 src/comm/LinkManager.cc     |  8 +++++---
 src/comm/MAVLinkProtocol.cc | 10 +++++-----
 src/comm/MAVLinkProtocol.h  |  6 +++++-
 3 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/src/comm/LinkManager.cc b/src/comm/LinkManager.cc
index dd0cefcb2..6c5385199 100644
--- a/src/comm/LinkManager.cc
+++ b/src/comm/LinkManager.cc
@@ -68,10 +68,12 @@ LinkManager::LinkManager(QObject* parent, bool registerSingleton) :
     _connectionsSuspended(false),
     _mavlink(NULL)
 {
-    Q_ASSERT(_instance == NULL);
-    _instance = this;
+    if (registerSingleton) {
+        Q_ASSERT(_instance == NULL);
+        _instance = this;
+    }
     
-    _mavlink = new MAVLinkProtocol;
+    _mavlink = new MAVLinkProtocol(this);
     Q_CHECK_PTR(_mavlink);
 }
 
diff --git a/src/comm/MAVLinkProtocol.cc b/src/comm/MAVLinkProtocol.cc
index f30424415..8fb72a3d4 100644
--- a/src/comm/MAVLinkProtocol.cc
+++ b/src/comm/MAVLinkProtocol.cc
@@ -39,7 +39,7 @@ const char* MAVLinkProtocol::_logFileExtension = "mavlink";             ///< Ext
  * The default constructor will create a new MAVLink object sending heartbeats at
  * the MAVLINK_HEARTBEAT_DEFAULT_RATE to all connected links.
  */
-MAVLinkProtocol::MAVLinkProtocol() :
+MAVLinkProtocol::MAVLinkProtocol(LinkManager* linkMgr) :
     heartbeatTimer(NULL),
     heartbeatRate(MAVLINK_HEARTBEAT_DEFAULT_RATE),
     m_heartbeatsEnabled(true),
@@ -58,8 +58,8 @@ MAVLinkProtocol::MAVLinkProtocol() :
     _logSuspendReplay(false),
     _tempLogFile(QString("%2.%3").arg(_tempLogFileTemplate).arg(_logFileExtension)),
     _protocolStatusMessageConnected(false),
-    _saveTempFlightDataLogConnected(false)
-
+    _saveTempFlightDataLogConnected(false),
+    _linkMgr(linkMgr)
 {
     qRegisterMetaType<mavlink_message_t>("mavlink_message_t");
     
@@ -452,7 +452,7 @@ void MAVLinkProtocol::receiveBytes(LinkInterface* link, QByteArray b)
             if (m_multiplexingEnabled)
             {
                 // Get all links connected to this unit
-                QList<LinkInterface*> links = LinkManager::instance()->getLinks();
+                QList<LinkInterface*> links = _linkMgr->getLinks();
 
                 // Emit message on all links that are currently connected
                 foreach (LinkInterface* currLink, links)
@@ -497,7 +497,7 @@ int MAVLinkProtocol::getComponentId()
 void MAVLinkProtocol::sendMessage(mavlink_message_t message)
 {
     // Get all links connected to this unit
-    QList<LinkInterface*> links = LinkManager::instance()->getLinks();
+    QList<LinkInterface*> links = _linkMgr->getLinks();
 
     // Emit message on all links that are currently connected
     QList<LinkInterface*>::iterator i;
diff --git a/src/comm/MAVLinkProtocol.h b/src/comm/MAVLinkProtocol.h
index f379296d4..1c87ed0a1 100644
--- a/src/comm/MAVLinkProtocol.h
+++ b/src/comm/MAVLinkProtocol.h
@@ -43,6 +43,8 @@ This file is part of the QGROUNDCONTROL project
 #include "QGC.h"
 #include "QGCTemporaryFile.h"
 
+class LinkManager;
+
 /**
  * @brief MAVLink micro air vehicle protocol reference implementation.
  *
@@ -55,7 +57,7 @@ class MAVLinkProtocol : public QThread
     Q_OBJECT
     
 public:
-    MAVLinkProtocol();
+    MAVLinkProtocol(LinkManager *linkMgr);
     ~MAVLinkProtocol();
 
     /** @brief Get the human-friendly name of this protocol */
@@ -297,6 +299,8 @@ private:
     
     bool _protocolStatusMessageConnected;   ///< true: protocolStatusMessage signal has been connected
     bool _saveTempFlightDataLogConnected;   ///< true: saveTempFlightDataLog signal has been connected
+    
+    LinkManager* _linkMgr;
 };
 
 #endif // MAVLINKPROTOCOL_H_
-- 
2.22.0