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/*
* tuple_formatter.c
* Copyright (c) 2007-2013 William Pitcock and John Lindgren
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions, and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions, and the following disclaimer in the documentation
* provided with the distribution.
*
* This software is provided "as is" and without any warranty, express or
* implied. In no event shall the authors be liable for any damages arising from
* the use of this software.
*/
#include <glib.h>
#include "tuple.h"
#include "tuple_compiler.h"
/*
* the tuple formatter:
*
* this is a data-driven meta-language which eventually hopes to be
* turing complete.
*
* language constructs follow the following basic rules:
* - begin with ${
* - end with }
*
* language constructs:
* - ${field}: prints a field
* - ${?field:expr}: evaluates expr if field exists
* - ${=field,"value"}: defines field in the currently iterated
* tuple as string value of "value"
* - ${=field,value}: defines field in the currently iterated
* tuple as integer value of "value"
* - ${==field,field:expr}: evaluates expr if both fields are the same
* - ${!=field,field:expr}: evaluates expr if both fields are not the same
* - ${(empty)?field:expr}: evaluates expr if field is empty or does not exist
* - %{function:args,arg2,...}: runs function and inserts the result.
*
* everything else is treated as raw text.
*/
struct _TupleFormatter
{
TupleEvalContext * context;
TupleEvalNode * node;
GString * buf;
};
EXPORT TupleFormatter * tuple_formatter_new (const char * format)
{
TupleFormatter * formatter = g_slice_new (TupleFormatter);
formatter->context = tuple_evalctx_new ();
formatter->node = tuple_formatter_compile (formatter->context, format);
formatter->buf = g_string_sized_new (255);
return formatter;
}
EXPORT void tuple_formatter_free (TupleFormatter * formatter)
{
tuple_evalctx_free (formatter->context);
tuple_evalnode_free (formatter->node);
g_string_free (formatter->buf, TRUE);
g_slice_free (TupleFormatter, formatter);
}
EXPORT char * tuple_format_title (TupleFormatter * formatter, const Tuple * tuple)
{
tuple_formatter_eval (formatter->context, formatter->node, tuple, formatter->buf);
tuple_evalctx_reset (formatter->context);
if (formatter->buf->len)
return str_get (formatter->buf->str);
/* formatting failed, try fallbacks */
static const int fallbacks[] = {FIELD_TITLE, FIELD_FILE_NAME};
for (int i = 0; i < ARRAY_LEN (fallbacks); i ++)
{
char * title = tuple_get_str (tuple, fallbacks[i]);
if (title)
return title;
}
return str_get ("");
}
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