Reduce the amount of stat traffic generated by a walk.
When we switched to the new walk code for commands, we no longer passed a
list of specific files to the repo or dirstate walk or changes methods.
This meant that we always walked and attempted to match everything,
which was not efficient.
Now, if we are given any patterns to match, or nothing at all, we still
walk everything. But if we are given only file names that contain no
glob characters, we only walk those.
# 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
import util
class transaction:
def __init__(self, report, opener, journal, after = None):
self.journal = None
# abort here if the journal already exists
if os.path.exists(journal):
raise "journal already exists - run hg recover"
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):
if file in self.map: return
self.entries.append((file, offset))
self.map[file] = 1
# add enough data to the journal to do the truncate
self.file.write("%s\0%d\n" % (file, offset))
self.file.flush()
def close(self):
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 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):
for l in open(file).readlines():
f, o = l.split('\0')
opener(f, "a").truncate(int(o))
os.unlink(file)