added a seperate chache lookup, as encode() requires arguments expensive to build

src/libstrongswan/credentials/keys/key_encoding.c

@@ -110,6 +110,28 @@ static bool equals(void *key1, void *key2)
 	return key1 == key2;
 }
 
+/**
+ * Implementation of key_encoding_t.get_cache
+ */
+static bool get_cache(private_key_encoding_t *this, key_encoding_type_t type,
+					  void *cache, chunk_t *encoding)
+{
+	chunk_t *chunk;
+	
+	if (type >= KEY_ENCODING_MAX || type < 0)
+	{
+		return FALSE;
+	}
+	this->lock->read_lock(this->lock);
+	chunk = this->cache[type]->get(this->cache[type], cache);
+	if (chunk)
+	{
+		*encoding = *chunk;
+	}
+	this->lock->unlock(this->lock);
+	return !!chunk;
+}
+
 /**
  * Implementation of key_encoding_t.encode
  */
@@ -239,6 +261,7 @@ key_encoding_t *key_encoding_create()
 	key_encoding_type_t type;
 	
 	this->public.encode = (bool(*)(key_encoding_t*, key_encoding_type_t type, void *cache, chunk_t *encoding, ...))encode;
+	this->public.get_cache = (bool(*)(key_encoding_t*, key_encoding_type_t type, void *cache, chunk_t *encoding))get_cache;
 	this->public.clear_cache = (void(*)(key_encoding_t*, void *cache))clear_cache;
 	this->public.add_encoder = (void(*)(key_encoding_t*, key_encoder_t encoder))add_encoder;
 	this->public.remove_encoder = (void(*)(key_encoding_t*, key_encoder_t encoder))remove_encoder;

src/libstrongswan/credentials/keys/key_encoding.h

@@ -136,6 +136,17 @@ struct key_encoding_t {
 	 */
 	void (*clear_cache)(key_encoding_t *this, void *cache);
 	
+	/**
+	 * Check for a cached encoding.
+	 *
+	 * @param type			format of the key encoding
+	 * @param cache			key to use for caching, as given to encode()
+	 * @encoding			encoding result, internal data
+	 * @return				TRUE if cache entry found
+	 */
+	bool (*get_cache)(key_encoding_t *this, key_encoding_type_t type,
+					  void *cache, chunk_t *encoding);
+	
 	/**
 	 * Register a key encoder function.
 	 *