1 files changed, 96 insertions, 0 deletions
diff --git a/kig/filters/filter.h b/kig/filters/filter.h
new file mode 100644
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+++ b/kig/filters/filter.h
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+// This file is part of Kig, a KDE program for Interactive Geometry...
+// Copyright (C)  2002  Dominique Devriese <devriese@kde.org>
+
+// This program is free software; you can redistribute it and/or
+// modify it under the terms of the GNU General Public License
+// as published by the Free Software Foundation; either version 2
+// of the License, or (at your option) any later version.
+
+// This program 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 General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program; if not, write to the Free Software
+// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+// 02110-1301, USA.
+
+#ifndef FILTER_H
+#define FILTER_H
+
+#include <qstring.h>
+
+#include <vector>
+
+class KigFilter;
+class ScreenInfo;
+class KigDocument;
+
+/**
+ * This singleton class handles all the input filters.
+ */
+class KigFilters
+{
+public:
+  static KigFilters* instance();
+  KigFilter* find (const QString& mime);
+
+//  bool save ( const KigDocument& data, QTextStream& stream );
+  /**
+   * saving is always done with the native filter.  We don't support
+   * output filters..
+   */
+  bool save ( const KigDocument& data, const QString& outfile );
+protected:
+  KigFilters();
+  static KigFilters* sThis;
+  typedef std::vector<KigFilter*> vect;
+  vect mFilters;
+};
+
+// KigFilter::load functions should use this macro to conveniently
+// return a very useful parse error in a filter's load function..
+#define KIG_FILTER_PARSE_ERROR \
+  { \
+    QString locs = i18n( "An error was encountered at " \
+                         "line %1 in file %2." ) \
+      .arg( __LINE__ ).arg( __FILE__ ); \
+    parseError( file, locs ); \
+    return 0; \
+  }
+
+/**
+ * This is the base class for an input filter.
+ *
+ * All the needed work to add a new input filter to Kig is
+ * subclassing this class and implement supportMime() and load().
+ */
+class KigFilter
+{
+protected:
+  // shows errors to the user..
+  void fileNotFound( const QString& file ) const;
+  void parseError( const QString& file, const QString& explanation = QString::null ) const;
+  void notSupported( const QString& file, const QString& explanation ) const;
+  void warning( const QString& explanation ) const;
+public:
+  KigFilter();
+  virtual ~KigFilter();
+
+  /**
+   * can the filter handle the mimetype \p mime ?
+   */
+  virtual bool supportMime ( const QString& mime );
+
+  /**
+   * load file \p fromfile and build a KigDocument from it..  If this
+   * function returns 0, that means that an error occurred while
+   * loading ( implementations of this function are responsible for
+   * showing an error message themselves, using the above error
+   * functions ). If this functions returns non-0, the caller owns
+   * the returned KigDocument ( that was allocated with "new" ).
+   */
+  virtual KigDocument* load ( const QString& fromfile ) = 0;
+};
+#endif