Changes to replace stat with attributes log2timeline#52

dfvfs/vfs/tsk_partition_file_entry.py

@@ -6,11 +6,10 @@
 from dfvfs.lib import tsk_partition
 from dfvfs.path import tsk_partition_path_spec
 from dfvfs.vfs import file_entry
-from dfvfs.vfs import vfs_stat
 
 
 class TSKPartitionDirectory(file_entry.Directory):
-  """Class that implements a directory object using pytsk3."""
+  """File system directory that uses pytsk3."""
 
   def _EntriesGenerator(self):
     """Retrieves directory entries.
@@ -61,66 +60,73 @@ def _EntriesGenerator(self):
 
 
 class TSKPartitionFileEntry(file_entry.FileEntry):
-  """Class that implements a file entry object using pytsk3."""
+  """File system file entry that uses pytsk3."""
 
   TYPE_INDICATOR = definitions.TYPE_INDICATOR_TSK_PARTITION
 
   def __init__(
       self, resolver_context, file_system, path_spec, is_root=False,
-      is_virtual=False):
-    """Initializes the file entry object.
+      is_virtual=False, tsk_vs_part=None):
+    """Initializes a file entry.
 
     Args:
-      resolver_context: the resolver context (instance of resolver.Context).
-      file_system: the file system object (instance of FileSystem).
-      path_spec: the path specification (instance of PathSpec).
-      is_virtual: optional boolean value to indicate if the file entry is
-                  a virtual file entry emulated by the corresponding file
-                  system.
+      resolver_context (Context): resolver context.
+      file_system (FileSystem): file system.
+      path_spec (PathSpec): path specification.
+      is_root (Optional[bool]): True if the file entry is the root file entry
+          of the corresponding file system.
+      is_virtual (Optional[bool]): True if the file entry is a virtual file
+          entry emulated by the corresponding file system.
+      tsk_vs_part (Optional[]):
+
+    Raises:
+      BackEndError: when the tsk volume system part is missing in a non-virtual
+          file entry.
     """
+    tsk_volume = file_system.GetTSKVolume()
+    if not is_virtual and tsk_vs_part is None:
+      tsk_vs_part, _ = tsk_partition.GetTSKVsPartByPathSpec(
+          tsk_volume, path_spec)
+    if not is_virtual and tsk_vs_part is None:
+      raise errors.BackEndError(
+          u'Missing tsk volume system part in non-virtual file entry.')
+
     super(TSKPartitionFileEntry, self).__init__(
         resolver_context, file_system, path_spec, is_root=is_root,
         is_virtual=is_virtual)
     self._name = None
+    self._tsk_volume = tsk_volume
+    self._tsk_vs_part = tsk_vs_part
+
+    if is_virtual:
+      self._type = definitions.FILE_ENTRY_TYPE_DIRECTORY
+    else:
+      self._type = definitions.FILE_ENTRY_TYPE_FILE
 
   def _GetDirectory(self):
     """Retrieves a directory.
 
     Returns:
-      A directory object (instance of Directory) or None.
+      TSKPartitionDirectory: a directory or None if not available.
     """
-    if self._stat_object is None:
-      self._stat_object = self._GetStat()
-
-    if (self._stat_object and
-        self._stat_object.type == self._stat_object.TYPE_DIRECTORY):
+    if self._type == definitions.FILE_ENTRY_TYPE_DIRECTORY:
       return TSKPartitionDirectory(self._file_system, self.path_spec)
-    return
 
   def _GetStat(self):
     """Retrieves the stat object.
 
     Returns:
-      The stat object (instance of vfs.VFSStat).
-
-    Raises:
-      BackEndError: when the tsk volume system part is missing in a non-virtual
-                    file entry.
+      VFSStat: stat object.
     """
-    tsk_vs_part = self.GetTSKVsPart()
-    stat_object = vfs_stat.VFSStat()
-
-    if not self._is_virtual and tsk_vs_part is None:
-      raise errors.BackEndError(
-          u'Missing tsk volume system part in non-virtual file entry.')
+    stat_object = super(TSKPartitionFileEntry, self)._GetStat()
 
-    tsk_volume = self._file_system.GetTSKVolume()
-    bytes_per_sector = tsk_partition.TSKVolumeGetBytesPerSector(tsk_volume)
+    bytes_per_sector = tsk_partition.TSKVolumeGetBytesPerSector(
+        self._tsk_volume)
 
     # File data stat information.
-    if tsk_vs_part is not None:
+    if self._tsk_vs_part is not None:
       number_of_sectors = tsk_partition.TSKVsPartGetNumberOfSectors(
-          tsk_vs_part)
+          self._tsk_vs_part)
 
       if number_of_sectors:
         stat_object.size = number_of_sectors * bytes_per_sector
@@ -132,20 +138,15 @@ def _GetStat(self):
     # File entry type stat information.
 
     # The root file entry is virtual and should have type directory.
-    if self._is_virtual:
-      stat_object.type = stat_object.TYPE_DIRECTORY
-    else:
-      stat_object.type = stat_object.TYPE_FILE
-
     if not self._is_virtual:
       stat_object.is_allocated = tsk_partition.TSKVsPartIsAllocated(
-          tsk_vs_part)
+          self._tsk_vs_part)
 
     return stat_object
 
   @property
   def name(self):
-    """The name of the file entry, which does not include the full path."""
+    """str: name of the file entry, which does not include the full path."""
     if self._name is None:
       # Directory entries without a location in the path specification
       # are not given a name for now.
@@ -158,7 +159,7 @@ def name(self):
 
   @property
   def sub_file_entries(self):
-    """The sub file entries (generator of instance of vfs.FileEntry)."""
+    """generator(TSKPartitionFileEntry): sub file entries."""
     if self._directory is None:
       self._directory = self._GetDirectory()
 
@@ -171,19 +172,16 @@ def GetParentFileEntry(self):
     """Retrieves the parent file entry.
 
     Returns:
-      The parent file entry (instance of FileEntry) or None.
+      TSKPartitionFileEntry: parent file entry or None if not available.
     """
     # TODO: implement https://github.com/log2timeline/dfvfs/issues/76.
     return
 
   def GetTSKVsPart(self):
-    """Retrieves the TSK volume system part object.
+    """Retrieves the TSK volume system part.
 
     Returns:
-      A TSK volume system part object (instance of pytsk3.TSK_VS_PART_INFO)
-      or None.
+      pytsk3.TSK_VS_PART_INFO: a TSK volume system part or None if not
+          available.
     """
-    tsk_volume = self._file_system.GetTSKVolume()
-    tsk_vs_part, _ = tsk_partition.GetTSKVsPartByPathSpec(
-        tsk_volume, self.path_spec)
-    return tsk_vs_part
+    return self._tsk_vs_part

tests/vfs/tsk_partition_file_entry.py

@@ -52,7 +52,7 @@ def testIntialize(self):
     """Test the __init__ function."""
     file_entry = tsk_partition_file_entry.TSKPartitionFileEntry(
         self._resolver_context, self._file_system,
-        self._tsk_partition_path_spec)
+        self._tsk_partition_path_spec, is_virtual=True)
 
     self.assertIsNotNone(file_entry)