Add lenses

- this adds the lens framework, although there are currently no interesting
  lenses.  display_args.c was mostly moved to lens_default.c

1 files changed, 51 insertions, 0 deletions

diff --git a/lens.h b/lens.h
new file mode 100644
index 0000000..f7de3b5
--- /dev/null
+++ b/lens.h
@@ -0,0 +1,51 @@
+/*
+ * This file is part of ltrace.
+ * Copyright (C) 2011 Petr Machata, Red Hat Inc.
+ *
+ * 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 St, Fifth Floor, Boston, MA
+ * 02110-1301 USA
+ */
+
+#ifndef LENS_H
+#define LENS_H
+
+#include <stdio.h>
+#include "forward.h"
+
+struct lens {
+	/* Format VALUE into STREAM.  The dictionary of all arguments
+	 * is given for purposes of evaluating array lengths and other
+	 * dynamic expressions.  Returns number of characters
+	 * outputted, -1 in case of failure.  */
+	int (*format_cb)(struct lens *lens, FILE *stream, struct value *value,
+			 struct value_dict *arguments);
+
+	/* Erase any memory allocated for LENS.  Keep the LENS pointer
+	 * itself intact.  */
+	void (*destroy_cb)(struct lens *lens);
+};
+
+/* Extracts a lens from VALUE and calls lens_format on that.  */
+int format_argument(FILE *stream, struct value *value,
+		    struct value_dict *arguments);
+
+/* Calls format callback associated with LENS.  */
+int lens_format(struct lens *lens, FILE *stream, struct value *value,
+		struct value_dict *arguments);
+
+/* Calls destroy callback associated with LENS.  */
+void lens_destroy(struct lens *lens);
+
+#endif /* LENS_H */