Add a comment at the top of the documentation Rakefile about generating

[arvados.git] / services / fuse / arvados_fuse / fusefile.py

diff --git a/services/fuse/arvados_fuse/fusefile.py b/services/fuse/arvados_fuse/fusefile.py
index d4c075a40d292f4515611a34706b7c670f831e18..116b5462b6857aa3452ae59407af309cdaabe36b 100644 (file)
--- a/services/fuse/arvados_fuse/fusefile.py
+++ b/services/fuse/arvados_fuse/fusefile.py
@@ -1,16 +1,24 @@
+# Copyright (C) The Arvados Authors. All rights reserved.
+#
+# SPDX-License-Identifier: AGPL-3.0
+
+from __future__ import absolute_import
+from builtins import bytes
 import json
 import llfuse
 import logging
 import re
 import time
 
-from fresh import FreshBase, convertTime
+from .fresh import FreshBase, convertTime
 
 _logger = logging.getLogger('arvados.arvados_fuse')
 
 class File(FreshBase):
     """Base for file objects."""
 
+    __slots__ = ("inode", "parent_inode", "_mtime")
+
     def __init__(self, parent_inode, _mtime=0):
         super(File, self).__init__()
         self.inode = None
@@ -29,8 +37,8 @@ class File(FreshBase):
     def mtime(self):
         return self._mtime
 
-    def clear(self, force=False):
-        return True
+    def clear(self):
+        pass
 
     def writable(self):
         return False
@@ -42,6 +50,8 @@ class File(FreshBase):
 class FuseArvadosFile(File):
     """Wraps a ArvadosFile."""
 
+    __slots__ = ('arvfile',)
+
     def __init__(self, parent_inode, arvfile, _mtime):
         super(FuseArvadosFile, self).__init__(parent_inode, _mtime)
         self.arvfile = arvfile
@@ -80,7 +90,7 @@ class StringFile(File):
         return len(self.contents)
 
     def readfrom(self, off, size, num_retries=0):
-        return self.contents[off:(off+size)]
+        return bytes(self.contents[off:(off+size)], encoding='utf-8')
 
 
 class ObjectFile(StringFile):
@@ -95,6 +105,12 @@ class ObjectFile(StringFile):
         return self.object_uuid
 
     def update(self, obj=None):
+        if obj is None:
+            # TODO: retrieve the current record for self.object_uuid
+            # from the server. For now, at least don't crash when
+            # someone tells us it's a good time to update but doesn't
+            # pass us a fresh obj. See #8345
+            return
         self._mtime = convertTime(obj['modified_at']) if 'modified_at' in obj else 0
         self.contents = json.dumps(obj, indent=4, sort_keys=True) + "\n"
 
@@ -112,6 +128,12 @@ class FuncToJSONFile(StringFile):
         super(FuncToJSONFile, self).__init__(parent_inode, "", 0)
         self.func = func
 
+        # invalidate_inode() is asynchronous with no callback to wait for. In
+        # order to guarantee userspace programs don't get stale data that was
+        # generated before the last invalidate(), we must disallow inode
+        # caching entirely.
+        self.allow_attr_cache = False
+
     def size(self):
         self._update()
         return super(FuncToJSONFile, self).size()