From 794b7e54860fd0a49108169c16babfcd05a63e6f Mon Sep 17 00:00:00 2001
From: Charl Wentzel <charl.wentzel@vodamail.co.za>
Date: Mon, 17 Jun 2019 12:43:12 +0200
Subject: [PATCH] Important Update: - FunctionCore:   - Implement
 UnlinkChannel()     - Avoid memory errors on application shutdown (state
 events)     - Unlink channels before destroying in Function destructor   -
 Bug fix: Linked Channels not added correctly

---
 FunctionCore.cpp | 69 +++++++++++++++++++++++++++++++++++++++---------
 FunctionCore.h   |  1 +
 2 files changed, 57 insertions(+), 13 deletions(-)

diff --git a/FunctionCore.cpp b/FunctionCore.cpp
index 3fc9596..c7cc299 100644
--- a/FunctionCore.cpp
+++ b/FunctionCore.cpp
@@ -48,18 +48,15 @@ CFunctionCore::~CFunctionCore()
     // Destroy Channels
     while (FirstChannel)
     {
-        // Destroy Parameters
-        if (FirstChannel->Name) {
-            free( FirstChannel->Name );
-            free( FirstChannel->Ref );
-        }
-
         // Destroy Linked Channels
-        while (FirstChannel->FirstLink) {
-            NextLinkedChannel = FirstChannel->FirstLink->Next;
-            delete FirstChannel->FirstLink;
-            FirstChannel->FirstLink = NextLinkedChannel;
-        }
+        while (FirstChannel->FirstLink)
+            UnlinkChannel( FirstChannel->Name, FirstChannel->FirstLink->Function->Name, FirstChannel->FirstLink->Channel->Name );
+
+        // Destroy Parameters
+        if (FirstChannel->Name)
+            free( FirstChannel->Name );
+        if (FirstChannel->Ref)
+            free( FirstChannel->Ref );
 
         // Destroy Channel
         NextChannel = FirstChannel->Next;
@@ -280,7 +277,7 @@ bool CFunctionCore::LinkChannel( const char * ChannelName, const char * LinkFunc
 
     // Check if linked Channel exists
     LinkedChannel = &(Channel->FirstLink);
-    while (*LinkedChannel && ((*LinkedChannel)->Channel == LinkChannel))
+    while (*LinkedChannel && ((*LinkedChannel)->Channel != LinkChannel))
         LinkedChannel = &((*LinkedChannel)->Next);
     if (!*LinkedChannel)
         *LinkedChannel = new TChannelLink;
@@ -297,7 +294,7 @@ bool CFunctionCore::LinkChannel( const char * ChannelName, const char * LinkFunc
 
     // Find Linked channel on remote function
     LinkedChannel = &(LinkChannel->FirstLink);
-    while (*LinkedChannel && ((*LinkedChannel)->Channel == Channel))
+    while (*LinkedChannel && ((*LinkedChannel)->Channel != Channel))
         LinkedChannel = &((*LinkedChannel)->Next);
     if (!*LinkedChannel)
         *LinkedChannel = new TChannelLink;
@@ -315,6 +312,52 @@ bool CFunctionCore::LinkChannel( const char * ChannelName, const char * LinkFunc
 }
 //---------------------------------------------------------------------------
 
+bool CFunctionCore::UnlinkChannel( const char * ChannelName, const char * LinkFunctionName, const char * LinkChannelName )
+{
+    TChannel        * Channel           = NULL;
+    CFunctionCore   * LinkFunction      = NULL;
+    TChannel        * LinkChannel       = NULL;
+    TChannelLink    ** LinkedChannel    = NULL;
+    TChannelLink    * NextLinkedChannel = NULL;
+
+    // Check if Channels & Function exist
+    if (!(Channel = GetChannel( ChannelName )) ||
+        !(LinkFunction = Application->GetFunction( LinkFunctionName )) ||
+        !(LinkChannel = LinkFunction->GetChannel( LinkChannelName )) ) {
+        return false;
+    }
+
+    // Check if linked Channel exists
+    LinkedChannel = &(Channel->FirstLink);
+    while (*LinkedChannel && ((*LinkedChannel)->Channel != LinkChannel))
+        LinkedChannel = &((*LinkedChannel)->Next);
+
+    // Unlink channel
+    if (*LinkedChannel) {
+        if (Log)  Log->Message( LogLevel, dlLow, "%s/%s: Forward Channel Unlinked - '%s'-x->'%s'",
+                                ProcessName, Name, Channel->Ref, (*LinkedChannel)->Channel->Ref );
+        NextLinkedChannel = (*LinkedChannel)->Next;
+        delete *LinkedChannel;
+        *LinkedChannel = NextLinkedChannel;
+    }
+
+    // Find Linked channel on remote function
+    LinkedChannel = &(LinkChannel->FirstLink);
+    while (*LinkedChannel && ((*LinkedChannel)->Channel != Channel))
+        LinkedChannel = &((*LinkedChannel)->Next);
+
+    // Unlink channel
+    if (*LinkedChannel) {
+        if (Log)  Log->Message( LogLevel, dlLow, "%s/%s: Reverse Channel Unlinked - '%s'-x->'%s'",
+                                ProcessName, Name, LinkChannel->Ref, (*LinkedChannel)->Channel->Ref );
+        NextLinkedChannel = (*LinkedChannel)->Next;
+        delete *LinkedChannel;
+        *LinkedChannel = NextLinkedChannel;
+    }
+    return true;
+}
+//---------------------------------------------------------------------------
+
 int CFunctionCore::Input( const char * ChannelName, const char * SourceRef, const char * Data, int Len )
 {
     TChannel    * Channel     = NULL;
diff --git a/FunctionCore.h b/FunctionCore.h
index 090bdd2..6f77962 100644
--- a/FunctionCore.h
+++ b/FunctionCore.h
@@ -130,6 +130,7 @@ public:
 
     // Automated Data Input/Output
     virtual bool LinkChannel( const char * ChannelName, const char * LinkFunctionName, const char * LinkChannelName, bool Input, bool Output );
+    virtual bool UnlinkChannel( const char * ChannelName, const char * LinkFunctionName, const char * LinkChannelName );
     virtual bool Process() = 0;
 
     friend class CApplication;