services/fuse/arvados_fuse/fusefile.py

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