Add getMaxLines to history

Add the getMaxLines function to return the maximum number of lines it
is alowed to compactHistoryScroll.

src/history/HistoryScroll.h

@@ -32,6 +32,7 @@ public:
 
     // access to history
     virtual int  getLines() = 0;
+    virtual int  getMaxLines() = 0;
     virtual int  getLineLen(int lineno) = 0;
     virtual void getCells(int lineno, int colno, int count, Character res[]) = 0;
     virtual bool isWrappedLine(int lineNumber) = 0;

src/history/HistoryScrollFile.cpp

@@ -33,6 +33,11 @@ int HistoryScrollFile::getLines()
     return _index.len() / sizeof(qint64);
 }
 
+int HistoryScrollFile::getMaxLines()
+{
+    return _index.len() / sizeof(qint64);
+}
+
 int HistoryScrollFile::getLineLen(int lineno)
 {
     return (startOfLine(lineno + 1) - startOfLine(lineno)) / sizeof(Character);

src/history/HistoryScrollFile.h

@@ -27,6 +27,7 @@ public:
     ~HistoryScrollFile() override;
 
     int  getLines() override;
+    int  getMaxLines() override;
     int  getLineLen(int lineno) override;
     void getCells(int lineno, int colno, int count, Character res[]) override;
     bool isWrappedLine(int lineno) override;

src/history/HistoryScrollNone.cpp

@@ -30,6 +30,11 @@ int HistoryScrollNone::getLines()
     return 0;
 }
 
+int HistoryScrollNone::getMaxLines()
+{
+    return 0;
+}
+
 int HistoryScrollNone::getLineLen(int)
 {
     return 0;

src/history/HistoryScrollNone.h

@@ -26,6 +26,7 @@ public:
     bool hasScroll() override;
 
     int  getLines() override;
+    int  getMaxLines() override;
     int  getLineLen(int lineno) override;
     void getCells(int lineno, int colno, int count, Character res[]) override;
     bool isWrappedLine(int lineno) override;

src/history/compact/CompactHistoryScroll.cpp

@@ -57,6 +57,11 @@ int CompactHistoryScroll::getLines()
     return _lines.size();
 }
 
+int CompactHistoryScroll::getMaxLines()
+{
+    return static_cast<int>(_maxLineCount);
+}
+
 int CompactHistoryScroll::getLineLen(int lineNumber)
 {
     if ((lineNumber < 0) || (lineNumber >= _lines.size())) {

src/history/compact/CompactHistoryScroll.h

@@ -24,6 +24,7 @@ public:
     ~CompactHistoryScroll() override;
 
     int  getLines() override;
+    int  getMaxLines() override;
     int  getLineLen(int lineNumber) override;
     void getCells(int lineNumber, int startColumn, int count, Character buffer[]) override;
     bool isWrappedLine(int lineNumber) override;