Still not having added Fl_Tree and Fl_Table to Fluid, I remembered the plugin concept we had early on. It occured to me that writing plugins must not be difficult, and that FLTK already has everything needed. So here it is, a plugin implementation for FLTK. The MSWindows/Cygwin implementation is untested due to lack of a machine. The dynamic loading still needs a test implementation. Comments welcome.

git-svn-id: file:///fltk/svn/fltk/branches/branch-1.3@7023 ea41ed52-d2ee-0310-a9c1-e6b18d33e121

2 files changed, 116 insertions, 5 deletions

diff --git a/FL/Fl_Plugin.H b/FL/Fl_Plugin.H
new file mode 100644
index 000000000..dcfc3bcdb
--- /dev/null
+++ b/FL/Fl_Plugin.H
@@ -0,0 +1,105 @@
+//
+// "$Id: Fl_Plugin.H 6995 2010-01-12 08:48:55Z matt $"
+//
+// A Plugin system for FLTK, implemented in Fl_Preferences.cxx.
+//
+// Copyright 2002-2010 by Matthias Melcher.
+//
+// This library is free software; you can redistribute it and/or
+// modify it under the terms of the GNU Library General Public
+// License as published by the Free Software Foundation; either
+// version 2 of the License, or (at your option) any later version.
+//
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+// Library General Public License for more details.
+//
+// You should have received a copy of the GNU Library General Public
+// License along with this library; if not, write to the Free Software
+// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
+// USA.
+//
+// Please report all bugs and problems on the following page:
+//
+//     http://www.fltk.org/str.php
+//
+
+/* \file
+   Fl_Plugin class . */
+
+#ifndef Fl_Plugin_H
+#  define Fl_Plugin_H
+
+#  include "Fl_Preferences.H"
+
+
+/**
+ \brief Fl_Plugin allows link-time and run-time integration of binary modules.
+ 
+ Fl_Plugin and Fl_Plugin_Manager provide a small and simple solution for
+ linking C++ classes at run-time, or optionally linking modules at compile
+ time without the need to change the main application.
+
+ Fl_Plugin_Manager uses static initialisation to create the plugin interface
+ early during startup. Plugins are stored in a temporary database, organized
+ in classes.
+ 
+ Plugins should derive a new class from Fl_Plugin as a base:
+ \code
+ class My_Plugin : public Fl_Plugin {
+ public:
+   My_Plugin() : Fl_Plugin("effects", "blur") { }
+   void do_something(...);
+ };
+ My_Plugin blur_plugin();
+ \endcode
+ 
+ Plugins can be put into modules and either linked befor distribution, or loaded
+ from dynamically linkable files. An Fl_Plugin_Manager is used to list and 
+ access all currently loaded plugins.
+ \code
+ Fl_Plugin_Manager mgr("effects");
+ int i, n = mgr.plugins();
+ for (i=0; i<n; i++) {
+   My_Plugin *pin = (My_Plugin*)mgr.plugin(i);
+   pin->do_something();
+ }
+ \endcode
+ */
+class FL_EXPORT Fl_Plugin 
+{
+  Fl_Preferences::ID id;
+public:
+  Fl_Plugin(const char *klass, const char *name);
+  virtual ~Fl_Plugin();
+};
+
+
+/**
+ \brief Fl_Plugin_Manager manages link-time and run-time plugin binaries.
+ \see Fl_Plugin
+ */
+class FL_EXPORT Fl_Plugin_Manager : public Fl_Preferences
+{
+public:
+  Fl_Plugin_Manager(const char *klass);
+  ~Fl_Plugin_Manager();
+  
+  /** \brief Return the number of plugins in the klass.
+   */
+  int plugins() { return groups(); }
+  Fl_Plugin *plugin(int index);
+  Fl_Preferences::ID addPlugin(const char *name, Fl_Plugin *plugin);
+  
+  static void removePlugin(Fl_Preferences::ID id);
+  static int load(const char *filename);
+  static int loadAll(const char *filepath, const char *pattern=0);
+};
+
+
+#endif // !Fl_Preferences_H
+
+//
+// End of "$Id: Fl_Preferences.H 6995 2010-01-12 08:48:55Z matt $".
+//
diff --git a/FL/Fl_Preferences.H b/FL/Fl_Preferences.H
index 44d007f90..798e421d6 100644
--- a/FL/Fl_Preferences.H
+++ b/FL/Fl_Preferences.H
@@ -61,7 +61,7 @@
    reasons. One application can have multiple preferences files.
    Extensive binary data however should be stored in separate
    files: see getUserdataPath().
-
+ 
    \note Starting with FLTK 1.3, preference databases are expected to 
    be in utf8 encoding. Previous databases were stored in the 
    current chracter set or code page which renders them incompatible
@@ -97,12 +97,17 @@ public:
   Fl_Preferences( Fl_Preferences *parent, const char *group );
   Fl_Preferences( Fl_Preferences &parent, int groupIndex );
   Fl_Preferences( Fl_Preferences *parent, int groupIndex );
+  Fl_Preferences(const Fl_Preferences&);
   Fl_Preferences( ID id );
   ~Fl_Preferences();
   
   /** Return an ID that can later be reused to open more references to this dataset.
    */
   ID id() { return (ID)node; }
+  
+  /** Remove the group with this ID from a databse.
+   */
+  static char remove(ID id) { return ((Node*)id)->remove(); }
 
   /** Return the name of this entry.
    */
@@ -189,13 +194,12 @@ public:
 
 private:
 
-  // make the following functions unavailable
-  Fl_Preferences(); 
-  Fl_Preferences(const Fl_Preferences&); 
+  Fl_Preferences() : node(0), rootNode(0) { }
   Fl_Preferences &operator=(const Fl_Preferences&);
 
   static char nameBuffer[128];
   static char uuidBuffer[40];
+  static Fl_Preferences *runtimePrefs;
 
   class RootNode;
   
@@ -253,6 +257,7 @@ private:
   public:
     RootNode( Fl_Preferences *, Root root, const char *vendor, const char *application );
     RootNode( Fl_Preferences *, const char *path, const char *vendor, const char *application );
+    RootNode( Fl_Preferences * );
     ~RootNode();
     int read();
     int write();
@@ -260,9 +265,10 @@ private:
   };
   friend class RootNode;
 
+protected:
+  
   Node *node;
   RootNode *rootNode;
-  
 };