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 class FuseArvadosFile(File):
  41     """Wraps a ArvadosFile."""
  42
  43     def __init__(self, parent_inode, arvfile, _mtime):
  44         super(FuseArvadosFile, self).__init__(parent_inode, _mtime)
  45         self.arvfile = arvfile
  46
  47     def size(self):
  48         return self.arvfile.size()
  49
  50     def readfrom(self, off, size, num_retries=0):
  51         return self.arvfile.readfrom(off, size, num_retries, exact=True)
  52
  53     def writeto(self, off, buf, num_retries=0):
  54         return self.arvfile.writeto(off, buf, num_retries)
  55
  56     def stale(self):
  57         return False
  58
  59     def writable(self):
  60         return self.arvfile.writable()
  61
  62     def flush(self):
  63         with llfuse.lock_released:
  64             if self.writable():
  65                 self.arvfile.parent.root_collection().save()
  66
  67
  68 class StringFile(File):
  69     """Wrap a simple string as a file"""
  70     def __init__(self, parent_inode, contents, _mtime):
  71         super(StringFile, self).__init__(parent_inode, _mtime)
  72         self.contents = contents
  73
  74     def size(self):
  75         return len(self.contents)
  76
  77     def readfrom(self, off, size, num_retries=0):
  78         return self.contents[off:(off+size)]
  79
  80
  81 class ObjectFile(StringFile):
  82     """Wrap a dict as a serialized json object."""
  83
  84     def __init__(self, parent_inode, obj):
  85         super(ObjectFile, self).__init__(parent_inode, "", 0)
  86         self.object_uuid = obj['uuid']
  87         self.update(obj)
  88
  89     def uuid(self):
  90         return self.object_uuid
  91
  92     def update(self, obj=None):
  93         self._mtime = convertTime(obj['modified_at']) if 'modified_at' in obj else 0
  94         self.contents = json.dumps(obj, indent=4, sort_keys=True) + "\n"
  95
  96     def persisted(self):
  97         return True