lib/file: protect from double close

Signed-off-by: Jean Privat <jean@pryen.org>

diff --git a/lib/standard/file.nit b/lib/standard/file.nit
index b0fa322..9c280dc 100644 (file)
--- a/lib/standard/file.nit
+++ b/lib/standard/file.nit
@@ -89,10 +89,11 @@ class IFStream
 
        redef fun close
        do
-               if _file.address_is_null then return
+               if _file == null or _file.address_is_null then return
                var i = _file.io_close
                _buffer.clear
                end_reached = true
+               _file = null
        end
 
        redef fun fill_buffer
@@ -154,6 +155,7 @@ class OFStream
 
        redef fun close
        do
+               if _file == null then return
                if _file.address_is_null then
                        if last_error != null then return
                        last_error = new IOError("Cannot close unopened write stream")
@@ -165,6 +167,7 @@ class OFStream
                        last_error = new IOError("Close failed due to error {sys.errno.strerror}")
                end
                _is_writable = false
+               _file = null
        end
        redef var is_writable = false