Added GetExtents method to data stream #597 (#638)

dfvfs/vfs/apfs_file_entry.py

@@ -208,31 +208,28 @@ def GetAPFSFileEntry(self):
     """
     return self._fsapfs_file_entry
 
-  def GetExtents(self, data_stream_name=''):
-    """Retrieves extents of a specific data stream.
-
-    Args:
-      data_stream_name (Optional[str]): data stream name, where an empty
-          string represents the default data stream.
+  def GetExtents(self):
+    """Retrieves the extents.
 
     Returns:
-      list[Extent]: extents of the data stream.
+      list[Extent]: the extents.
     """
+    if self.entry_type != definitions.FILE_ENTRY_TYPE_FILE:
+      return []
+
     extents = []
-    if (self.entry_type == definitions.FILE_ENTRY_TYPE_FILE and
-        not data_stream_name):
-      for extent_index in range(self._fsapfs_file_entry.number_of_extents):
-        extent_offset, extent_size, extent_flags = (
-            self._fsapfs_file_entry.get_extent(extent_index))
-
-        if extent_flags & 0x1:
-          extent_type = definitions.EXTENT_TYPE_SPARSE
-        else:
-          extent_type = definitions.EXTENT_TYPE_DATA
-
-        data_stream_extent = extent.Extent(
-            extent_type=extent_type, offset=extent_offset, size=extent_size)
-        extents.append(data_stream_extent)
+    for extent_index in range(self._fsapfs_file_entry.number_of_extents):
+      extent_offset, extent_size, extent_flags = (
+          self._fsapfs_file_entry.get_extent(extent_index))
+
+      if extent_flags & 0x1:
+        extent_type = definitions.EXTENT_TYPE_SPARSE
+      else:
+        extent_type = definitions.EXTENT_TYPE_DATA
+
+      data_stream_extent = extent.Extent(
+          extent_type=extent_type, offset=extent_offset, size=extent_size)
+      extents.append(data_stream_extent)
 
     return extents
 

dfvfs/vfs/data_stream.py

@@ -5,18 +5,35 @@
 class DataStream(object):
   """Data stream interface."""
 
-  # The data stream object should not have a reference to its
-  # file entry since that will create a cyclic reference.
+  def __init__(self, file_entry):
+    """Initializes the data stream.
+
+    Args:
+      file_entry (FileEntry): file entry.
+    """
+    super(DataStream, self).__init__()
+    self._file_entry = file_entry
+    self._name = ''
 
   @property
   def name(self):
     """str: name."""
-    return ''
+    return self._name
+
+  def GetExtents(self):
+    """Retrieves the extents.
+
+    Returns:
+      list[Extent]: the extents of the data stream.
+    """
+    if self._file_entry:
+      return self._file_entry.GetExtents()
+    return []
 
   def IsDefault(self):
     """Determines if the data stream is the default data stream.
 
     Returns:
       bool: True if the data stream is the default data stream.
     """
-    return True
+    return not bool(self._name)

dfvfs/vfs/ext_file_entry.py

@@ -245,31 +245,28 @@ def size(self):
     """int: size of the file entry in bytes or None if not available."""
     return self._fsext_file_entry.size
 
-  def GetExtents(self, data_stream_name=''):
-    """Retrieves extents of a specific data stream.
-
-    Args:
-      data_stream_name (Optional[str]): data stream name, where an empty
-          string represents the default data stream.
+  def GetExtents(self):
+    """Retrieves the extents.
 
     Returns:
-      list[Extent]: extents of the data stream.
+      list[Extent]: the extents.
     """
+    if self.entry_type != definitions.FILE_ENTRY_TYPE_FILE:
+      return []
+
     extents = []
-    if (self.entry_type == definitions.FILE_ENTRY_TYPE_FILE and
-        not data_stream_name):
-      for extent_index in range(self._fsext_file_entry.number_of_extents):
-        extent_offset, extent_size, extent_flags = (
-            self._fsext_file_entry.get_extent(extent_index))
-
-        if extent_flags & 0x1:
-          extent_type = definitions.EXTENT_TYPE_SPARSE
-        else:
-          extent_type = definitions.EXTENT_TYPE_DATA
-
-        data_stream_extent = extent.Extent(
-            extent_type=extent_type, offset=extent_offset, size=extent_size)
-        extents.append(data_stream_extent)
+    for extent_index in range(self._fsext_file_entry.number_of_extents):
+      extent_offset, extent_size, extent_flags = (
+          self._fsext_file_entry.get_extent(extent_index))
+
+      if extent_flags & 0x1:
+        extent_type = definitions.EXTENT_TYPE_SPARSE
+      else:
+        extent_type = definitions.EXTENT_TYPE_DATA
+
+      data_stream_extent = extent.Extent(
+          extent_type=extent_type, offset=extent_offset, size=extent_size)
+      extents.append(data_stream_extent)
 
     return extents
 

dfvfs/vfs/file_entry.py

@@ -82,7 +82,7 @@ def _GetDataStreams(self):
 
       # It is assumed that non-file file entries do not have data streams.
       if self.entry_type == definitions.FILE_ENTRY_TYPE_FILE:
-        data_stream_object = data_stream.DataStream()
+        data_stream_object = data_stream.DataStream(self)
         self._data_streams.append(data_stream_object)
 
     return self._data_streams
@@ -308,15 +308,11 @@ def GetDataStream(self, name, case_sensitive=True):
 
     return matching_data_stream
 
-  def GetExtents(self, data_stream_name=''):  # pylint: disable=unused-argument
-    """Retrieves extents of a specific data stream.
-
-    Args:
-      data_stream_name (Optional[str]): data stream name, where an empty
-          string represents the default data stream.
+  def GetExtents(self):
+    """Retrieves the extents.
 
     Returns:
-      list[Extent]: extents of the data stream.
+      list[Extent]: the extents.
     """
     return []
 

dfvfs/vfs/hfs_data_stream.py

@@ -1,34 +1,48 @@
 # -*- coding: utf-8 -*-
 """The HFS data stream implementation."""
 
+from dfvfs.lib import definitions
 from dfvfs.vfs import data_stream
+from dfvfs.vfs import extent
 
 
 class HFSDataStream(data_stream.DataStream):
   """File system data stream that uses pyfshfs."""
 
-  def __init__(self, fshfs_data_stream):
-    """Initializes the data stream.
+  def __init__(self, file_entry, fshfs_data_stream):
+    """Initializes a HFS data stream.
 
     Args:
+      file_entry (FileEntry): file entry.
       fshfs_data_stream (pyfshfs.data_stream): HFS data stream.
     """
-    super(HFSDataStream, self).__init__()
+    super(HFSDataStream, self).__init__(file_entry)
     self._fshfs_data_stream = fshfs_data_stream
-    self._name = ''
 
     if fshfs_data_stream:
       self._name = 'rsrc'
 
-  @property
-  def name(self):
-    """str: name."""
-    return self._name
-
-  def IsDefault(self):
-    """Determines if the data stream is the default (data fork) data stream.
+  def GetExtents(self):
+    """Retrieves the extents.
 
     Returns:
-      bool: True if the data stream is the default (data fork) data stream.
+      list[Extent]: the extents of the data stream.
     """
-    return not self._fshfs_data_stream
+    if not self._fshfs_data_stream:
+      return super(HFSDataStream, self).GetExtents()
+
+    extents = []
+    for extent_index in range(self._fshfs_data_stream.number_of_extents):
+      extent_offset, extent_size, extent_flags = (
+          self._fshfs_data_stream.get_extent(extent_index))
+
+      if extent_flags & 0x1:
+        extent_type = definitions.EXTENT_TYPE_SPARSE
+      else:
+        extent_type = definitions.EXTENT_TYPE_DATA
+
+      data_stream_extent = extent.Extent(
+          extent_type=extent_type, offset=extent_offset, size=extent_size)
+      extents.append(data_stream_extent)
+
+    return extents

dfvfs/vfs/hfs_file_entry.py

@@ -98,12 +98,12 @@ def _GetDataStreams(self):
       self._data_streams = []
 
       if self.entry_type == definitions.FILE_ENTRY_TYPE_FILE:
-        data_stream = hfs_data_stream.HFSDataStream(None)
+        data_stream = hfs_data_stream.HFSDataStream(self, None)
         self._data_streams.append(data_stream)
 
       fshfs_data_stream = self._fshfs_file_entry.get_resource_fork()
       if fshfs_data_stream:
-        data_stream = hfs_data_stream.HFSDataStream(fshfs_data_stream)
+        data_stream = hfs_data_stream.HFSDataStream(self, fshfs_data_stream)
         self._data_streams.append(data_stream)
 
     return self._data_streams
@@ -246,47 +246,28 @@ def size(self):
     """int: size of the file entry in bytes or None if not available."""
     return self._fshfs_file_entry.size
 
-  def GetExtents(self, data_stream_name=''):
-    """Retrieves extents of a specific data stream.
-
-    Args:
-      data_stream_name (Optional[str]): data stream name, where an empty
-          string represents the default data stream.
+  def GetExtents(self):
+    """Retrieves the extents.
 
     Returns:
-      list[Extent]: extents of the data stream.
+      list[Extent]: the extents.
     """
+    if self.entry_type != definitions.FILE_ENTRY_TYPE_FILE:
+      return []
+
     extents = []
-    if (self.entry_type == definitions.FILE_ENTRY_TYPE_FILE and
-        not data_stream_name):
-      for extent_index in range(self._fshfs_file_entry.number_of_extents):
-        extent_offset, extent_size, extent_flags = (
-            self._fshfs_file_entry.get_extent(extent_index))
-
-        if extent_flags & 0x1:
-          extent_type = definitions.EXTENT_TYPE_SPARSE
-        else:
-          extent_type = definitions.EXTENT_TYPE_DATA
-
-        data_stream_extent = extent.Extent(
-            extent_type=extent_type, offset=extent_offset, size=extent_size)
-        extents.append(data_stream_extent)
-
-    elif data_stream_name == 'rsrc':
-      fshfs_data_stream = self._fshfs_file_entry.get_resource_fork()
-      if fshfs_data_stream:
-        for extent_index in range(fshfs_data_stream.number_of_extents):
-          extent_offset, extent_size, extent_flags = (
-              fshfs_data_stream.get_extent(extent_index))
-
-          if extent_flags & 0x1:
-            extent_type = definitions.EXTENT_TYPE_SPARSE
-          else:
-            extent_type = definitions.EXTENT_TYPE_DATA
-
-          data_stream_extent = extent.Extent(
-              extent_type=extent_type, offset=extent_offset, size=extent_size)
-          extents.append(data_stream_extent)
+    for extent_index in range(self._fshfs_file_entry.number_of_extents):
+      extent_offset, extent_size, extent_flags = (
+          self._fshfs_file_entry.get_extent(extent_index))
+
+      if extent_flags & 0x1:
+        extent_type = definitions.EXTENT_TYPE_SPARSE
+      else:
+        extent_type = definitions.EXTENT_TYPE_DATA
+
+      data_stream_extent = extent.Extent(
+          extent_type=extent_type, offset=extent_offset, size=extent_size)
+      extents.append(data_stream_extent)
 
     return extents
 

dfvfs/vfs/ntfs_data_stream.py

@@ -1,30 +1,48 @@
 # -*- coding: utf-8 -*-
 """The NTFS data stream implementation."""
 
+from dfvfs.lib import definitions
 from dfvfs.vfs import data_stream
+from dfvfs.vfs import extent
 
 
 class NTFSDataStream(data_stream.DataStream):
   """File system data stream that uses pyfsntfs."""
 
-  def __init__(self, fsntfs_data_stream):
-    """Initializes the data stream.
+  def __init__(self, file_entry, fsntfs_data_stream):
+    """Initializes a NTFS data stream.
 
     Args:
+      file_entry (FileEntry): file entry.
       fsntfs_data_stream (pyfsntfs.data_stream): NTFS data stream.
     """
-    super(NTFSDataStream, self).__init__()
-    self._name = getattr(fsntfs_data_stream, 'name', None) or ''
+    super(NTFSDataStream, self).__init__(file_entry)
+    self._fsntfs_data_stream = fsntfs_data_stream
 
-  @property
-  def name(self):
-    """str: name."""
-    return self._name
+    if fsntfs_data_stream:
+      self._name = fsntfs_data_stream.name
 
-  def IsDefault(self):
-    """Determines if the data stream is the default data stream.
+  def GetExtents(self):
+    """Retrieves the extents.
 
     Returns:
-      bool: True if the data stream is the default data stream.
+      list[Extent]: the extents of the data stream.
     """
-    return not bool(self._name)
+    if not self._fsntfs_data_stream:
+      return super(NTFSDataStream, self).GetExtents()
+
+    extents = []
+    for extent_index in range(self._fsntfs_data_stream.number_of_extents):
+      extent_offset, extent_size, extent_flags = (
+          self._fsntfs_data_stream.get_extent(extent_index))
+
+      if extent_flags & 0x1:
+        extent_type = definitions.EXTENT_TYPE_SPARSE
+      else:
+        extent_type = definitions.EXTENT_TYPE_DATA
+
+      data_stream_extent = extent.Extent(
+          extent_type=extent_type, offset=extent_offset, size=extent_size)
+      extents.append(data_stream_extent)
+
+    return extents