ADD: Introduce virtual and real file source into hierarchy.

src/newdesign/ulocalfilesource.pas

@@ -6,7 +6,7 @@ interface
 
 uses
   Classes, SysUtils,
-  uFileSource;
+  uRealFileSource;
 
 type
 
@@ -15,7 +15,7 @@ type
      Empty placeholder for now, allows to check
      whether a certain file source is local.
   }
-  TLocalFileSource = class(TFileSource)
+  TLocalFileSource = class(TRealFileSource)
   end;
 
 implementation

src/newdesign/urealfilesource.pas

@@ -0,0 +1,23 @@
+unit uRealFileSource;
+
+{$mode objfpc}{$H+}
+
+interface
+
+uses
+  Classes, SysUtils,
+  uFileSource;
+
+type
+
+  {en
+     Base class for any real file source
+     (filesystem, archive, network, ... - all sources able to produce real files).
+  }
+  TRealFileSource = class(TFileSource)
+  end;
+
+implementation
+
+end.
+

src/newdesign/uvirtualfilesource.pas

@@ -0,0 +1,24 @@
+unit uVirtualFileSource;
+
+{$mode objfpc}{$H+}
+
+interface
+
+uses
+  Classes, SysUtils,
+  uFileSource;
+
+type
+
+  {en
+     Base class for any virtual file source
+     (this can be any list of files, internal lists, temporary,
+      links to favourite files, results from search queries, etc.).
+  }
+  TVirtualFileSource = class(TFileSource)
+  end;
+
+implementation
+
+end.
+