Fixed selection of previous dir in FileListWidget.

I was going to have it remember descending directories too, but it's just too much fooling
around for a minor feature.  Maybe someone else can take a stab at it ...

src/common/LinkedObjectPool.hxx

@@ -266,7 +266,6 @@ class LinkedObjectPool
       for(const auto& i: p.myList)
         os << i << (p.current() == i ? "* " : "  ");
       return os;
-
     }
 
   private:

src/common/Stack.hxx

@@ -49,6 +49,13 @@ class FixedStack
     T pop() { return std::move(_stack[--_size]); }
     uInt32 size() const { return _size; }
 
+    // Reverse the contents of the stack
+    // This operation isn't needed very often, but it's handy to have
+    void reverse() {
+      for(uInt32 i = 0, j = _size - 1; i < j; ++i, --j)
+        std::swap(_stack[i], _stack[j]);
+    }
+
     // Apply the given function to every item in the stack
     // We do it this way so the stack API can be preserved,
     // and no access to individual elements is allowed outside
@@ -58,6 +65,12 @@ class FixedStack
         func(_stack[i]);
     }
 
+    friend ostream& operator<<(ostream& os, const FixedStack<T>& s) {
+      for(uInt32 pos = 0; pos < s._size; ++pos)
+        os << s._stack[pos] << " ";
+      return os;
+    }
+
   private:
     // Following constructors and assignment operators not supported
     FixedStack(const FixedStack&) = delete;

src/gui/FileListWidget.cxx

@@ -50,6 +50,31 @@ void FileListWidget::setDirectory(const FilesystemNode& node, string select)
     _node = _node.getParent();
   }
 
+  // Initialize history
+  FilesystemNode tmp = _node;
+  while(tmp.hasParent())
+  {
+    string name = tmp.getName();
+    if(name.back() == '/' || name.back() == '\\')
+      name.pop_back();
+    if(!BSPF::startsWithIgnoreCase(name, " ["))
+      name = " [" + name + "]";
+
+    _history.push(name);
+    tmp = tmp.getParent();
+  }
+  // History is in reverse order; we need to fix that
+  _history.reverse();
+
+  // Finally, go to this location
+  setLocation(_node, select);
+}
+
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+void FileListWidget::setLocation(const FilesystemNode& node, const string& select)
+{
+  _node = node;
+
   // Read in the data from the file system (start with an empty list)
   _fileList.clear();
   _fileList.reserve(512);
@@ -67,9 +92,10 @@ void FileListWidget::setDirectory(const FilesystemNode& node, string select)
 }
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-void FileListWidget::setLocation(const FilesystemNode& node, string select)
+void FileListWidget::selectDirectory()
 {
-  setDirectory(node, select);
+  _history.push(selected().getName());
+  setLocation(selected());
 }
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@@ -77,13 +103,7 @@ void FileListWidget::selectParent()
 {
   if(_node.hasParent())
   {
-    // Make sure 'selected' has the proper directory naming scheme
-    string select = _node.getName();
-    if(select.back() == '/' || select.back() == '\\')
-      select.pop_back();
-    if(!BSPF::startsWithIgnoreCase(select, " ["))
-      select = " [" + select + "]";
-
+    const string& select = !_history.empty() ? _history.pop() : EmptyString;
     setLocation(_node.getParent(), select);
   }
 }
@@ -115,7 +135,7 @@ void FileListWidget::handleCommand(CommandSender* sender, int cmd, int data, int
       if(selected().isDirectory())
       {
         cmd = ItemChanged;
-        setLocation(selected(), "");
+        selectDirectory();
       }
       else
         cmd = ItemActivated;

src/gui/FileListWidget.hxx

@@ -21,7 +21,7 @@
 class CommandSender;
 
 #include "FSNode.hxx"
-#include "LinkedObjectPool.hxx"
+#include "Stack.hxx"
 #include "StringListWidget.hxx"
 
 /**
@@ -74,7 +74,10 @@ class FileListWidget : public StringListWidget
 
   private:
     /** Very similar to setDirectory(), but also updates the history */
-    void setLocation(const FilesystemNode& node, string select);
+    void setLocation(const FilesystemNode& node, const string& select = EmptyString);
+
+    /** Descend into currently selected directory */
+    void selectDirectory();
 
     void handleCommand(CommandSender* sender, int cmd, int data, int id) override;
 
@@ -83,7 +86,7 @@ class FileListWidget : public StringListWidget
     FilesystemNode _node;
     FSList _fileList;
 
-    Common::LinkedObjectPool<string> _history;
+    Common::FixedStack<string> _history;
 
     string _extension;
     uInt32 _selected;