services/fuse/arvados_fuse/fusefile.py

   1 import logging
   2 import re
   3 import json
   4 import llfuse
   5
   6 from fresh import FreshBase, convertTime
   7
   8 _logger = logging.getLogger('arvados.arvados_fuse')
   9
  10 class File(FreshBase):
  11     """Base for file objects."""
  12
  13     def __init__(self, parent_inode, _mtime=0):
  14         super(File, self).__init__()
  15         self.inode = None
  16         self.parent_inode = parent_inode
  17         self._mtime = _mtime
  18
  19     def size(self):
  20         return 0
  21
  22     def readfrom(self, off, size, num_retries=0):
  23         return ''
  24
  25     def writeto(self, off, size, num_retries=0):
  26         raise Exception("Not writable")
  27
  28     def mtime(self):
  29         return self._mtime
  30
  31     def clear(self, force=False):
  32         return True
  33
  34     def writable(self):
  35         return False
  36
  37     def flush(self):
  38         pass
  39
  40
  41 class FuseArvadosFile(File):
  42     """Wraps a ArvadosFile."""
  43
  44     def __init__(self, parent_inode, arvfile, _mtime):
  45         super(FuseArvadosFile, self).__init__(parent_inode, _mtime)
  46         self.arvfile = arvfile
  47
  48     def size(self):
  49         _logger.debug("started calling self.arvfile.size()")
  50         with llfuse.lock_released:
  51             _logger.debug("locked_released and calling self.arvfile.size()")
  52             return self.arvfile.size()
  53
  54     def readfrom(self, off, size, num_retries=0):
  55         with llfuse.lock_released:
  56             return self.arvfile.readfrom(off, size, num_retries, exact=True)
  57
  58     def writeto(self, off, buf, num_retries=0):
  59         with llfuse.lock_released:
  60             return self.arvfile.writeto(off, buf, num_retries)
  61
  62     def stale(self):
  63         return False
  64
  65     def writable(self):
  66         return self.arvfile.writable()
  67
  68     def flush(self):
  69         with llfuse.lock_released:
  70             if self.writable():
  71                 self.arvfile.parent.root_collection().save()
  72
  73
  74 class StringFile(File):
  75     """Wrap a simple string as a file"""
  76     def __init__(self, parent_inode, contents, _mtime):
  77         super(StringFile, self).__init__(parent_inode, _mtime)
  78         self.contents = contents
  79
  80     def size(self):
  81         return len(self.contents)
  82
  83     def readfrom(self, off, size, num_retries=0):
  84         return self.contents[off:(off+size)]
  85
  86
  87 class ObjectFile(StringFile):
  88     """Wrap a dict as a serialized json object."""
  89
  90     def __init__(self, parent_inode, obj):
  91         super(ObjectFile, self).__init__(parent_inode, "", 0)
  92         self.object_uuid = obj['uuid']
  93         self.update(obj)
  94
  95     def uuid(self):
  96         return self.object_uuid
  97
  98     def update(self, obj=None):
  99         self._mtime = convertTime(obj['modified_at']) if 'modified_at' in obj else 0
 100         self.contents = json.dumps(obj, indent=4, sort_keys=True) + "\n"
 101
 102     def persisted(self):
 103         return True