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