Proper check to see if zip dest needs to be wrapped in tellable
From hgweb, calling archival.zipit fails with the error message
"Illegal seek". This happens because sys.stdout.tell() throws an
exception:
Traceback (most recent call last):
File "/usr/lib/python2.4/site-packages/mercurial/archival.py", line 99, in addfile
self.z.writestr(i, data)
File "/usr/lib/python2.4/zipfile.py", line 468, in writestr
zinfo.header_offset = self.fp.tell() # Start of header bytes
Checking whether hasattr(dest, 'tell') is insufficient, because
sys.stdout has a tell() method; you just can't call it.
This patch instead determines whether a fileobj is tellable by trying
to tell(), wrapping the fileobj if an exception is generated.
# transaction.py - simple journalling scheme for mercurial
#
# This transaction scheme is intended to gracefully handle program
# errors and interruptions. More serious failures like system crashes
# can be recovered with an fsck-like tool. As the whole repository is
# effectively log-structured, this should amount to simply truncating
# anything that isn't referenced in the changelog.
#
# Copyright 2005 Matt Mackall <mpm@selenic.com>
#
# This software may be used and distributed according to the terms
# of the GNU General Public License, incorporated herein by reference.
import os
from i18n import gettext as _
class transaction(object):
def __init__(self, report, opener, journal, after=None):
self.journal = None
# abort here if the journal already exists
if os.path.exists(journal):
raise AssertionError(_("journal already exists - run hg recover"))
self.count = 1
self.report = report
self.opener = opener
self.after = after
self.entries = []
self.map = {}
self.journal = journal
self.file = open(self.journal, "w")
def __del__(self):
if self.journal:
if self.entries: self.abort()
self.file.close()
try: os.unlink(self.journal)
except: pass
def add(self, file, offset, data=None):
if file in self.map: return
self.entries.append((file, offset, data))
self.map[file] = len(self.entries) - 1
# add enough data to the journal to do the truncate
self.file.write("%s\0%d\n" % (file, offset))
self.file.flush()
def find(self, file):
if file in self.map:
return self.entries[self.map[file]]
return None
def replace(self, file, offset, data=None):
if file not in self.map:
raise KeyError(file)
index = self.map[file]
self.entries[index] = (file, offset, data)
self.file.write("%s\0%d\n" % (file, offset))
self.file.flush()
def nest(self):
self.count += 1
return self
def running(self):
return self.count > 0
def close(self):
self.count -= 1
if self.count != 0:
return
self.file.close()
self.entries = []
if self.after:
self.after()
else:
os.unlink(self.journal)
self.journal = None
def abort(self):
if not self.entries: return
self.report(_("transaction abort!\n"))
for f, o, ignore in self.entries:
try:
self.opener(f, "a").truncate(o)
except:
self.report(_("failed to truncate %s\n") % f)
self.entries = []
self.report(_("rollback completed\n"))
def rollback(opener, file):
files = {}
for l in open(file).readlines():
f, o = l.split('\0')
files[f] = o
for f in files:
o = files[f]
opener(f, "a").truncate(int(o))
os.unlink(file)