moved history navigation to its own class

YACReaderLibrary/yacreader_history_controller.cpp

@@ -0,0 +1,66 @@
+#include "yacreader_history_controller.h"
+
+YACReaderHistoryController::YACReaderHistoryController(QObject *parent) :
+    QObject(parent)
+{
+}
+
+void YACReaderHistoryController::clear()
+{
+    currentFolderNavigation = 0;
+    history.clear();
+    history.append(QModelIndex()); //root folder is always the first item
+
+    emit(enabledBackward(false));
+    emit(enabledForward(false));
+}
+
+void YACReaderHistoryController::backward()
+{
+    if(currentFolderNavigation>0)
+    {
+        currentFolderNavigation--;
+        emit(modelIndexSelected(history.at(currentFolderNavigation)));
+        emit(enabledForward(true));
+    }
+
+    if(currentFolderNavigation==0)
+        emit(enabledBackward(false));
+}
+
+void YACReaderHistoryController::forward()
+{
+    if(currentFolderNavigation<history.count()-1)
+    {
+        currentFolderNavigation++;
+        emit(modelIndexSelected(history.at(currentFolderNavigation)));
+        emit(enabledBackward(true));
+    }
+
+    if(currentFolderNavigation==history.count()-1)
+        emit(enabledForward(false));
+}
+
+void YACReaderHistoryController::updateHistory(const QModelIndex &mi)
+{
+    //remove history from current index
+    if(!mi.isValid() && history.count() == 1)
+        return;
+
+    int numElementsToRemove = history.count() - (currentFolderNavigation+1);
+    while(numElementsToRemove>0)
+    {
+        numElementsToRemove--;
+        history.removeLast();
+    }
+
+    if(mi!=history.at(currentFolderNavigation))
+    {
+        history.append(mi);
+
+        emit(enabledBackward(true));
+        currentFolderNavigation++;
+    }
+
+    emit(enabledForward(false));
+}