add: cache size control for djvureader

djvu.c

@@ -72,6 +72,7 @@ static int handle(lua_State *L, ddjvu_context_t *ctx, int wait)
 static int openDocument(lua_State *L) {
 	const char *filename = luaL_checkstring(L, 1);
 	/*const char *password = luaL_checkstring(L, 2);*/
+	int cache_size = luaL_optint(L, 2, 10 << 20);
 
 	DjvuDocument *doc = (DjvuDocument*) lua_newuserdata(L, sizeof(DjvuDocument));
 	luaL_getmetatable(L, "djvudocument");
@@ -81,6 +82,7 @@ static int openDocument(lua_State *L) {
 	if (! doc->context) {
 		return luaL_error(L, "cannot create context.");
 	}
+	ddjvu_cache_set_size(doc->context, (unsigned long)cache_size);
 
 	doc->doc_ref = ddjvu_document_create_by_filename_utf8(doc->context, filename, TRUE);
 	while (! ddjvu_document_decoding_done(doc->doc_ref))

djvureader.lua

@@ -6,7 +6,7 @@ DJVUReader = UniReader:new{}
 -- DJVU does not support password yet
 function DJVUReader:open(filename)
 	local ok
-	ok, self.doc = pcall(djvu.openDocument, filename)
+	ok, self.doc = pcall(djvu.openDocument, filename, 10*1024*1024)
 	if not ok then
 		return ok, self.doc -- this will be the error message instead
 	end