cache: Improve _strip_invalid_entites() API

Add more information to documentation.
Add a check on the input string to make sure we avoid crashes.
Add test case

1 files changed, 9 insertions, 1 deletions

diff --git a/libmediaart/cache.c b/libmediaart/cache.c
index 774e2cf..2e29bae 100644
--- a/libmediaart/cache.c
+++ b/libmediaart/cache.c
@@ -94,7 +94,13 @@ media_art_strip_find_next_block (const gchar    *original,
  * This functions is used internally by media_art_get_file() and
  * media_art_get_path(). You will not normally need to call it yourself.
  *
- * Returns: copy of original but then stripped
+ * This function provides the following features:
+ * 1. Invalid characters include: ()[]<>{}_!@#$^&*+=|\/"'?~;
+ * 2. Text inside brackets of (), {}, [] and <> pairs are removed.
+ * 3. Multiples of space characters are removed.
+ *
+ * Returns: @original stripped of invalid characters which must be
+ * freed. On error or if @original is empty, %NULL is returned.
  *
  * Since: 0.2.0
  */
@@ -118,6 +124,8 @@ media_art_strip_invalid_entities (const gchar *original)
 		{  0,   0  }
 	};
 
+	g_return_val_if_fail (original != NULL, NULL);
+
 	str_no_blocks = g_string_new ("");
 
 	p = original;