import thread
from xml.etree import ElementTree
from bmaptools.BmapHelpers import human_size
+from bmaptools import TransRead
# A list of supported image formats
-SUPPORTED_IMAGE_FORMATS = ('bz2', 'gz', 'tar.gz', 'tgz', 'tar.bz2')
+SUPPORTED_IMAGE_FORMATS = TransRead.SUPPORTED_COMPRESSION_TYPES
# The highest supported bmap format version
SUPPORTED_BMAP_VERSION = 1
possible, because this adds several useful sanity checks. """
if self.image_size is not None and self.image_size != image_size:
- raise Error("Cannot set image size to %d bytes, it is known to " \
+ raise Error("cannot set image size to %d bytes, it is known to " \
"be %d bytes (%s)" % (image_size, self.image_size,
self.image_size_human))
self.image_size = image_size
self._f_bmap.seek(bmap_pos)
- def _open_image_file(self):
- """ Open the image file which may be compressed or not. The compression
- type is recognized by the file extension. Supported types are defined
- by 'SUPPORTED_IMAGE_FORMATS'. """
-
- try:
- is_regular_file = stat.S_ISREG(os.stat(self._image_path).st_mode)
- except OSError as err:
- raise Error("cannot access image file '%s': %s" \
- % (self._image_path, err.strerror))
-
- if not is_regular_file:
- raise Error("image file '%s' is not a regular file" \
- % self._image_path)
-
- try:
- if self._image_path.endswith('.tar.gz') \
- or self._image_path.endswith('.tar.bz2') \
- or self._image_path.endswith('.tgz'):
- import tarfile
-
- tar = tarfile.open(self._image_path, 'r')
- # The tarball is supposed to contain only one single member
- members = tar.getnames()
- if len(members) > 1:
- raise Error("the image tarball '%s' contains more than " \
- "one file" % self._image_path)
- elif len(members) == 0:
- raise Error("the image tarball '%s' is empty (no files)" \
- % self._image_path)
- self._f_image = tar.extractfile(members[0])
- elif self._image_path.endswith('.gz'):
- import gzip
- self._f_image = gzip.GzipFile(self._image_path, 'rb')
- elif self._image_path.endswith('.bz2'):
- import bz2
- self._f_image = bz2.BZ2File(self._image_path, 'rb')
- else:
- self._image_is_compressed = False
- self._f_image = open(self._image_path, 'rb')
- except IOError as err:
- raise Error("cannot open image file '%s': %s" \
- % (self._image_path, err))
-
- self._f_image_needs_close = True
-
- def _validate_image_size(self):
- """ Make sure that image size from bmap matches real image size. """
-
- image_size = os.fstat(self._f_image.fileno()).st_size
- if image_size != self.image_size:
- raise Error("Size mismatch, bmap '%s' was created for an image " \
- "of size %d bytes, but image '%s' has size %d bytes" \
- % (self._bmap_path, self.image_size,
- self._image_path, image_size))
-
def _open_destination_file(self):
""" Open the destination file. """
copying """
self._xml = None
- self._image_is_compressed = True
self._dest_fsync_watermark = None
self._batch_blocks = None
if hasattr(image, "read"):
self._f_image = image
self._image_path = image.name
+ real_image_size = None
else:
self._image_path = image
- self._open_image_file()
+ self._f_image = TransRead.TransRead(image)
+ real_image_size = self._f_image.size
st_mode = os.fstat(self._f_dest.fileno()).st_mode
self._dest_is_regfile = stat.S_ISREG(st_mode)
else:
self._bmap_path = bmap
self._open_bmap_file()
+
self._parse_bmap()
else:
# There is no bmap. Initialize user-visible attributes to something
self.block_size = 4096
self.mapped_percent = 100
- # We can initialize size-related attributes only if the image is
- # not compressed.
- if not self._image_is_compressed:
- image_size = os.fstat(self._f_image.fileno()).st_size
- self.set_image_size(image_size)
-
- if not self._image_is_compressed:
- self._validate_image_size()
+ if real_image_size:
+ self.set_image_size(real_image_size)
self._batch_blocks = self._batch_bytes / self.block_size
--- /dev/null
+""" This module allows opening and reading various kind of files irrespectively
+on whether the file is compressed or not. If it is compressed, this module will
+decompress the contents on-the-fly. """
+
+import os
+import stat
+
+# A list of supported compression types
+SUPPORTED_COMPRESSION_TYPES = ('bz2', 'gz', 'tar.gz', 'tgz', 'tar.bz2')
+
+class Error(Exception):
+ """ A class for exceptions generated by this module. We currently support
+ only one type of exceptions, and we basically throw human-readable problem
+ description in case of errors. """
+ pass
+
+class TransRead:
+ """ This class implement the transparent reading functionality. Instances
+ of this class are file-like objects which you can read and seek only
+ forward.
+ """
+
+ def _open_compressed_file(self):
+ """ Detect file compression type and open it with the corresponding
+ compression module, or just plain 'open() if the file is not
+ compressed. """
+
+ try:
+ if self.filepath.endswith('.tar.gz') \
+ or self.filepath.endswith('.tar.bz2') \
+ or self.filepath.endswith('.tgz'):
+ import tarfile
+
+ tar = tarfile.open(self.filepath, 'r')
+ # The tarball is supposed to contain only one single member
+ members = tar.getnames()
+ if len(members) > 1:
+ raise Error("tarball '%s' contains more than one file" \
+ % self.filepath)
+ elif len(members) == 0:
+ raise Error("tarball '%s' is empty (no files)" \
+ % self.filepath)
+
+ self._transfile_obj = tar.extractfile(members[0])
+ elif self.filepath.endswith('.gz'):
+ import gzip
+
+ self._transfile_obj = gzip.GzipFile(self.filepath, 'rb')
+ elif self.filepath.endswith('.bz2'):
+ import bz2
+
+ self._transfile_obj = bz2.BZ2File(self.filepath, 'rb')
+ else:
+ self.is_compressed = False
+ self._transfile_obj = self._file_obj
+ self.size = os.fstat(self._file_obj.fileno()).st_size
+ self._file_obj = None
+ except IOError as err:
+ raise Error("cannot open file '%s': %s" % (self.filepath, err))
+
+ def close(self):
+ """ Close the file-like object. """
+
+ self.__del__()
+
+ def __init__(self, filepath):
+ """ Class constructor. The 'filepath' argument is the full path to the
+ file to read transparently. """
+
+ self.filepath = filepath
+ self.size = None
+ self.is_compressed = True
+
+ self._transfile_obj = None
+
+ try:
+ self._file_obj = open(filepath, "rb")
+ except IOError as err:
+ raise Error("cannot open file '%s': %s" % (filepath, err))
+
+ st_mode = os.fstat(self._file_obj.fileno()).st_mode
+ if not stat.S_ISREG(st_mode):
+ raise Error("file '%s' is not a regular file" % self.filepath)
+
+ self._open_compressed_file()
+
+ def __del__(self):
+ """ The class destructor which closes opened files. """
+
+ if self._transfile_obj:
+ self._transfile_obj.close()
+ if self._file_obj:
+ self._file_obj.close()
+
+ def __getattr__(self, name):
+ """ Called for all attributes that do not exist in the 'TransRead'
+ class. We are pretending to be file-like objects, so we just return the
+ attributes of the '_transfile_obj' file-like object. """
+
+ return getattr(self._transfile_obj, name)
projects / tools / bmap-tools.git / commitdiff