2853: Merge branch 'master' into 2853-rendezvous

[arvados.git] / sdk / python / arvados / arvfile.py

diff --git a/sdk/python/arvados/arvfile.py b/sdk/python/arvados/arvfile.py
new file mode 100644 (file)
index 0000000..e8dac46
--- /dev/null
+++ b/sdk/python/arvados/arvfile.py
@@ -0,0 +1,29 @@
+import functools
+
+class ArvadosFileBase(object):
+    def __init__(self, name, mode):
+        self.name = name
+        self.mode = mode
+        self.closed = False
+
+    @staticmethod
+    def _before_close(orig_func):
+        @functools.wraps(orig_func)
+        def wrapper(self, *args, **kwargs):
+            if self.closed:
+                raise ValueError("I/O operation on closed stream file")
+            return orig_func(self, *args, **kwargs)
+        return wrapper
+
+    def __enter__(self):
+        return self
+
+    def __exit__(self, exc_type, exc_value, traceback):
+        try:
+            self.close()
+        except Exception:
+            if exc_type is None:
+                raise
+
+    def close(self):
+        self.closed = True