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         with llfuse.lock_released:
  50             return self.arvfile.size()
  51
  52     def readfrom(self, off, size, num_retries=0):
  53         with llfuse.lock_released:
  54             return self.arvfile.readfrom(off, size, num_retries, exact=True)
  55
  56     def writeto(self, off, buf, num_retries=0):
  57         with llfuse.lock_released:
  58             return self.arvfile.writeto(off, buf, num_retries)
  59
  60     def stale(self):
  61         return False
  62
  63     def writable(self):
  64         return self.arvfile.writable()
  65
  66     def flush(self):
  67         with llfuse.lock_released:
  68             if self.writable():
  69                 self.arvfile.parent.root_collection().save()
  70
  71
  72 class StringFile(File):
  73     """Wrap a simple string as a file"""
  74     def __init__(self, parent_inode, contents, _mtime):
  75         super(StringFile, self).__init__(parent_inode, _mtime)
  76         self.contents = contents
  77
  78     def size(self):
  79         return len(self.contents)
  80
  81     def readfrom(self, off, size, num_retries=0):
  82         return self.contents[off:(off+size)]
  83
  84
  85 class ObjectFile(StringFile):
  86     """Wrap a dict as a serialized json object."""
  87
  88     def __init__(self, parent_inode, obj):
  89         super(ObjectFile, self).__init__(parent_inode, "", 0)
  90         self.object_uuid = obj['uuid']
  91         self.update(obj)
  92
  93     def uuid(self):
  94         return self.object_uuid
  95
  96     def update(self, obj=None):
  97         self._mtime = convertTime(obj['modified_at']) if 'modified_at' in obj else 0
  98         self.contents = json.dumps(obj, indent=4, sort_keys=True) + "\n"
  99
 100     def persisted(self):
 101         return True