bundle2.unpackermixin: control for underlying file descriptor
This patch adds seek(), tell(), and close() implementations for unpackermixin
which forward to the file descriptor's implementation if possible. A future
patch will use this to make bundle2.unbundlepart seekable, which will in turn
make it usable as a file descriptor for bundlerepo.
--- a/mercurial/bundle2.py Fri Jan 16 15:34:03 2015 -0800
+++ b/mercurial/bundle2.py Wed Jan 14 14:24:16 2015 -0800
@@ -145,6 +145,7 @@
preserve.
"""
+import errno
import sys
import util
import struct
@@ -484,6 +485,8 @@
def __init__(self, fp):
self._fp = fp
+ self._seekable = (util.safehasattr(fp, 'seek') and
+ util.safehasattr(fp, 'tell'))
def _unpack(self, format):
"""unpack this struct format from the stream"""
@@ -494,6 +497,29 @@
"""read exactly <size> bytes from the stream"""
return changegroup.readexactly(self._fp, size)
+ def seek(self, offset, whence):
+ """move the underlying file pointer"""
+ if self._seekable:
+ return self._fp.seek(offset, whence)
+ else:
+ raise NotImplementedError(_('File pointer is not seekable'))
+
+ def tell(self):
+ """return the file offset, or None if file is not seekable"""
+ if self._seekable:
+ try:
+ return self._fp.tell()
+ except IOError, e:
+ if e.errno == errno.ESPIPE:
+ self._seekable = False
+ else:
+ raise
+ return None
+
+ def close(self):
+ """close underlying file"""
+ if util.safehasattr(self._fp, 'close'):
+ return self._fp.close()
class unbundle20(unpackermixin):
"""interpret a bundle2 stream