lib/core/stream: add start/finish for Stream

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

diff --git a/lib/core/stream.nit b/lib/core/stream.nit
index b4a0e2b..ecfc77e 100644 (file)
--- a/lib/core/stream.nit
+++ b/lib/core/stream.nit
@@ -39,6 +39,26 @@ abstract class Stream
 
        # close the stream
        fun close is abstract
+
+       # Pre-work hook.
+       #
+       # Used to inform `self` that operations will start.
+       # Specific streams can use this to prepare some resources.
+       #
+       # Is automatically invoked at the beginning of `with` structures.
+       #
+       # Do nothing by default.
+       fun start do end
+
+       # Post-work hook.
+       #
+       # Used to inform `self` that the operations are over.
+       # Specific streams can use this to free some resources.
+       #
+       # Is automatically invoked at the end of `woth` structures.
+       #
+       # call `close` by default.
+       fun finish do close
 end
 
 # A `Stream` that can be read from