Patch #1230446: tarfile.py: fix ExFileObject so that read() and tell()
work correctly together with readline().
Will backport to 2.5.
diff --git a/Lib/tarfile.py b/Lib/tarfile.py
index ccbfdde..46031e1 100644
--- a/Lib/tarfile.py
+++ b/Lib/tarfile.py
@@ -628,64 +628,158 @@
#------------------------
# Extraction file object
#------------------------
-class ExFileObject(object):
- """File-like object for reading an archive member.
- Is returned by TarFile.extractfile(). Support for
- sparse files included.
+class _FileInFile(object):
+ """A thin wrapper around an existing file object that
+ provides a part of its data as an individual file
+ object.
"""
- def __init__(self, tarfile, tarinfo):
- self.fileobj = tarfile.fileobj
- self.name = tarinfo.name
- self.mode = "r"
- self.closed = False
- self.offset = tarinfo.offset_data
- self.size = tarinfo.size
- self.pos = 0L
- self.linebuffer = ""
- if tarinfo.issparse():
- self.sparse = tarinfo.sparse
- self.read = self._readsparse
- else:
- self.read = self._readnormal
+ def __init__(self, fileobj, offset, size, sparse=None):
+ self.fileobj = fileobj
+ self.offset = offset
+ self.size = size
+ self.sparse = sparse
+ self.position = 0
- def __read(self, size):
- """Overloadable read method.
+ def tell(self):
+ """Return the current file position.
"""
+ return self.position
+
+ def seek(self, position):
+ """Seek to a position in the file.
+ """
+ self.position = position
+
+ def read(self, size=None):
+ """Read data from the file.
+ """
+ if size is None:
+ size = self.size - self.position
+ else:
+ size = min(size, self.size - self.position)
+
+ if self.sparse is None:
+ return self.readnormal(size)
+ else:
+ return self.readsparse(size)
+
+ def readnormal(self, size):
+ """Read operation for regular files.
+ """
+ self.fileobj.seek(self.offset + self.position)
+ self.position += size
return self.fileobj.read(size)
- def readline(self, size=-1):
- """Read a line with approx. size. If size is negative,
- read a whole line. readline() and read() must not
- be mixed up (!).
+ def readsparse(self, size):
+ """Read operation for sparse files.
"""
- if size < 0:
- size = sys.maxint
+ data = []
+ while size > 0:
+ buf = self.readsparsesection(size)
+ if not buf:
+ break
+ size -= len(buf)
+ data.append(buf)
+ return "".join(data)
- nl = self.linebuffer.find("\n")
- if nl >= 0:
- nl = min(nl, size)
+ def readsparsesection(self, size):
+ """Read a single section of a sparse file.
+ """
+ section = self.sparse.find(self.position)
+
+ if section is None:
+ return ""
+
+ size = min(size, section.offset + section.size - self.position)
+
+ if isinstance(section, _data):
+ realpos = section.realpos + self.position - section.offset
+ self.fileobj.seek(self.offset + realpos)
+ self.position += size
+ return self.fileobj.read(size)
else:
- size -= len(self.linebuffer)
- while (nl < 0 and size > 0):
- buf = self.read(min(size, 100))
- if not buf:
+ self.position += size
+ return NUL * size
+#class _FileInFile
+
+
+class ExFileObject(object):
+ """File-like object for reading an archive member.
+ Is returned by TarFile.extractfile().
+ """
+ blocksize = 1024
+
+ def __init__(self, tarfile, tarinfo):
+ self.fileobj = _FileInFile(tarfile.fileobj,
+ tarinfo.offset_data,
+ tarinfo.size,
+ getattr(tarinfo, "sparse", None))
+ self.name = tarinfo.name
+ self.mode = "r"
+ self.closed = False
+ self.size = tarinfo.size
+
+ self.position = 0
+ self.buffer = ""
+
+ def read(self, size=None):
+ """Read at most size bytes from the file. If size is not
+ present or None, read all data until EOF is reached.
+ """
+ if self.closed:
+ raise ValueError("I/O operation on closed file")
+
+ buf = ""
+ if self.buffer:
+ if size is None:
+ buf = self.buffer
+ self.buffer = ""
+ else:
+ buf = self.buffer[:size]
+ self.buffer = self.buffer[size:]
+
+ if size is None:
+ buf += self.fileobj.read()
+ else:
+ buf += self.fileobj.read(size - len(buf))
+
+ self.position += len(buf)
+ return buf
+
+ def readline(self, size=-1):
+ """Read one entire line from the file. If size is present
+ and non-negative, return a string with at most that
+ size, which may be an incomplete line.
+ """
+ if self.closed:
+ raise ValueError("I/O operation on closed file")
+
+ if "\n" in self.buffer:
+ pos = self.buffer.find("\n") + 1
+ else:
+ buffers = [self.buffer]
+ while True:
+ buf = self.fileobj.read(self.blocksize)
+ buffers.append(buf)
+ if not buf or "\n" in buf:
+ self.buffer = "".join(buffers)
+ pos = self.buffer.find("\n") + 1
+ if pos == 0:
+ # no newline found.
+ pos = len(self.buffer)
break
- self.linebuffer += buf
- size -= len(buf)
- nl = self.linebuffer.find("\n")
- if nl == -1:
- s = self.linebuffer
- self.linebuffer = ""
- return s
- buf = self.linebuffer[:nl]
- self.linebuffer = self.linebuffer[nl + 1:]
- while buf[-1:] == "\r":
- buf = buf[:-1]
- return buf + "\n"
+
+ if size != -1:
+ pos = min(size, pos)
+
+ buf = self.buffer[:pos]
+ self.buffer = self.buffer[pos:]
+ self.position += len(buf)
+ return buf
def readlines(self):
- """Return a list with all (following) lines.
+ """Return a list with all remaining lines.
"""
result = []
while True:
@@ -694,74 +788,34 @@
result.append(line)
return result
- def _readnormal(self, size=None):
- """Read operation for regular files.
- """
- if self.closed:
- raise ValueError("file is closed")
- self.fileobj.seek(self.offset + self.pos)
- bytesleft = self.size - self.pos
- if size is None:
- bytestoread = bytesleft
- else:
- bytestoread = min(size, bytesleft)
- self.pos += bytestoread
- return self.__read(bytestoread)
-
- def _readsparse(self, size=None):
- """Read operation for sparse files.
- """
- if self.closed:
- raise ValueError("file is closed")
-
- if size is None:
- size = self.size - self.pos
-
- data = []
- while size > 0:
- buf = self._readsparsesection(size)
- if not buf:
- break
- size -= len(buf)
- data.append(buf)
- return "".join(data)
-
- def _readsparsesection(self, size):
- """Read a single section of a sparse file.
- """
- section = self.sparse.find(self.pos)
-
- if section is None:
- return ""
-
- toread = min(size, section.offset + section.size - self.pos)
- if isinstance(section, _data):
- realpos = section.realpos + self.pos - section.offset
- self.pos += toread
- self.fileobj.seek(self.offset + realpos)
- return self.__read(toread)
- else:
- self.pos += toread
- return NUL * toread
-
def tell(self):
"""Return the current file position.
"""
- return self.pos
+ if self.closed:
+ raise ValueError("I/O operation on closed file")
- def seek(self, pos, whence=0):
+ return self.position
+
+ def seek(self, pos, whence=os.SEEK_SET):
"""Seek to a position in the file.
"""
- self.linebuffer = ""
- if whence == 0:
- self.pos = min(max(pos, 0), self.size)
- if whence == 1:
+ if self.closed:
+ raise ValueError("I/O operation on closed file")
+
+ if whence == os.SEEK_SET:
+ self.position = min(max(pos, 0), self.size)
+ elif whence == os.SEEK_CUR:
if pos < 0:
- self.pos = max(self.pos + pos, 0)
+ self.position = max(self.position + pos, 0)
else:
- self.pos = min(self.pos + pos, self.size)
- if whence == 2:
- self.pos = max(min(self.size + pos, self.size), 0)
+ self.position = min(self.position + pos, self.size)
+ elif whence == os.SEEK_END:
+ self.position = max(min(self.size + pos, self.size), 0)
+ else:
+ raise ValueError("Invalid argument")
+
+ self.buffer = ""
+ self.fileobj.seek(self.position)
def close(self):
"""Close the file object.
@@ -769,20 +823,13 @@
self.closed = True
def __iter__(self):
- """Get an iterator over the file object.
+ """Get an iterator over the file's lines.
"""
- if self.closed:
- raise ValueError("I/O operation on closed file")
- return self
-
- def next(self):
- """Get the next item from the file iterator.
- """
- result = self.readline()
- if not result:
- raise StopIteration
- return result
-
+ while True:
+ line = self.readline()
+ if not line:
+ break
+ yield line
#class ExFileObject
#------------------