|
|
# transaction.py - simple journaling 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, 2006 Matt Mackall <mpm@selenic.com>
|
|
|
#
|
|
|
# This software may be used and distributed according to the terms of the
|
|
|
# GNU General Public License version 2 or any later version.
|
|
|
|
|
|
from i18n import _
|
|
|
import errno
|
|
|
import error, util
|
|
|
|
|
|
version = 2
|
|
|
|
|
|
def active(func):
|
|
|
def _active(self, *args, **kwds):
|
|
|
if self.count == 0:
|
|
|
raise error.Abort(_(
|
|
|
'cannot use transaction when it is already committed/aborted'))
|
|
|
return func(self, *args, **kwds)
|
|
|
return _active
|
|
|
|
|
|
def _playback(journal, report, opener, vfsmap, entries, backupentries,
|
|
|
unlink=True):
|
|
|
for f, o, _ignore in entries:
|
|
|
if o or not unlink:
|
|
|
try:
|
|
|
fp = opener(f, 'a')
|
|
|
fp.truncate(o)
|
|
|
fp.close()
|
|
|
except IOError:
|
|
|
report(_("failed to truncate %s\n") % f)
|
|
|
raise
|
|
|
else:
|
|
|
try:
|
|
|
opener.unlink(f)
|
|
|
except (IOError, OSError), inst:
|
|
|
if inst.errno != errno.ENOENT:
|
|
|
raise
|
|
|
|
|
|
backupfiles = []
|
|
|
for l, f, b, c in backupentries:
|
|
|
if l not in vfsmap and c:
|
|
|
report("couldn't handle %s: unknown cache location %s\n"
|
|
|
% (b, l))
|
|
|
vfs = vfsmap[l]
|
|
|
try:
|
|
|
if f and b:
|
|
|
filepath = vfs.join(f)
|
|
|
backuppath = vfs.join(b)
|
|
|
try:
|
|
|
util.copyfile(backuppath, filepath)
|
|
|
backupfiles.append(b)
|
|
|
except IOError:
|
|
|
report(_("failed to recover %s\n") % f)
|
|
|
else:
|
|
|
target = f or b
|
|
|
try:
|
|
|
vfs.unlink(target)
|
|
|
except (IOError, OSError), inst:
|
|
|
if inst.errno != errno.ENOENT:
|
|
|
raise
|
|
|
except (IOError, OSError, util.Abort), inst:
|
|
|
if not c:
|
|
|
raise
|
|
|
|
|
|
opener.unlink(journal)
|
|
|
backuppath = "%s.backupfiles" % journal
|
|
|
if opener.exists(backuppath):
|
|
|
opener.unlink(backuppath)
|
|
|
try:
|
|
|
for f in backupfiles:
|
|
|
if opener.exists(f):
|
|
|
opener.unlink(f)
|
|
|
except (IOError, OSError, util.Abort), inst:
|
|
|
# only pure backup file remains, it is sage to ignore any error
|
|
|
pass
|
|
|
|
|
|
class transaction(object):
|
|
|
def __init__(self, report, opener, vfsmap, journalname, undoname=None,
|
|
|
after=None, createmode=None, validator=None):
|
|
|
"""Begin a new transaction
|
|
|
|
|
|
Begins a new transaction that allows rolling back writes in the event of
|
|
|
an exception.
|
|
|
|
|
|
* `after`: called after the transaction has been committed
|
|
|
* `createmode`: the mode of the journal file that will be created
|
|
|
"""
|
|
|
self.count = 1
|
|
|
self.usages = 1
|
|
|
self.report = report
|
|
|
# a vfs to the store content
|
|
|
self.opener = opener
|
|
|
# a map to access file in various {location -> vfs}
|
|
|
vfsmap = vfsmap.copy()
|
|
|
vfsmap[''] = opener # set default value
|
|
|
self._vfsmap = vfsmap
|
|
|
self.after = after
|
|
|
self.entries = []
|
|
|
self.map = {}
|
|
|
self.journal = journalname
|
|
|
self.undoname = undoname
|
|
|
self._queue = []
|
|
|
# A callback to validate transaction content before closing it.
|
|
|
# should raise exception is anything is wrong.
|
|
|
# target user is repository hooks.
|
|
|
if validator is None:
|
|
|
validator = lambda tr: None
|
|
|
self.validator = validator
|
|
|
# a dict of arguments to be passed to hooks
|
|
|
self.hookargs = {}
|
|
|
self.file = opener.open(self.journal, "w")
|
|
|
|
|
|
# a list of ('location', 'path', 'backuppath', cache) entries.
|
|
|
# - if 'backuppath' is empty, no file existed at backup time
|
|
|
# - if 'path' is empty, this is a temporary transaction file
|
|
|
# - if 'location' is not empty, the path is outside main opener reach.
|
|
|
# use 'location' value as a key in a vfsmap to find the right 'vfs'
|
|
|
# (cache is currently unused)
|
|
|
self._backupentries = []
|
|
|
self._backupmap = {}
|
|
|
self._backupjournal = "%s.backupfiles" % self.journal
|
|
|
self._backupsfile = opener.open(self._backupjournal, 'w')
|
|
|
self._backupsfile.write('%d\n' % version)
|
|
|
|
|
|
if createmode is not None:
|
|
|
opener.chmod(self.journal, createmode & 0666)
|
|
|
opener.chmod(self._backupjournal, createmode & 0666)
|
|
|
|
|
|
# hold file generations to be performed on commit
|
|
|
self._filegenerators = {}
|
|
|
# hold callback to write pending data for hooks
|
|
|
self._pendingcallback = {}
|
|
|
# True is any pending data have been written ever
|
|
|
self._anypending = False
|
|
|
# holds callback to call when writing the transaction
|
|
|
self._finalizecallback = {}
|
|
|
# hold callback for post transaction close
|
|
|
self._postclosecallback = {}
|
|
|
# holds callbacks to call during abort
|
|
|
self._abortcallback = {}
|
|
|
|
|
|
def __del__(self):
|
|
|
if self.journal:
|
|
|
self._abort()
|
|
|
|
|
|
@active
|
|
|
def startgroup(self):
|
|
|
"""delay registration of file entry
|
|
|
|
|
|
This is used by strip to delay vision of strip offset. The transaction
|
|
|
sees either none or all of the strip actions to be done."""
|
|
|
self._queue.append([])
|
|
|
|
|
|
@active
|
|
|
def endgroup(self):
|
|
|
"""apply delayed registration of file entry.
|
|
|
|
|
|
This is used by strip to delay vision of strip offset. The transaction
|
|
|
sees either none or all of the strip actions to be done."""
|
|
|
q = self._queue.pop()
|
|
|
for f, o, data in q:
|
|
|
self._addentry(f, o, data)
|
|
|
|
|
|
@active
|
|
|
def add(self, file, offset, data=None):
|
|
|
"""record the state of an append-only file before update"""
|
|
|
if file in self.map or file in self._backupmap:
|
|
|
return
|
|
|
if self._queue:
|
|
|
self._queue[-1].append((file, offset, data))
|
|
|
return
|
|
|
|
|
|
self._addentry(file, offset, data)
|
|
|
|
|
|
def _addentry(self, file, offset, data):
|
|
|
"""add a append-only entry to memory and on-disk state"""
|
|
|
if file in self.map or file in self._backupmap:
|
|
|
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()
|
|
|
|
|
|
@active
|
|
|
def addbackup(self, file, hardlink=True, location=''):
|
|
|
"""Adds a backup of the file to the transaction
|
|
|
|
|
|
Calling addbackup() creates a hardlink backup of the specified file
|
|
|
that is used to recover the file in the event of the transaction
|
|
|
aborting.
|
|
|
|
|
|
* `file`: the file path, relative to .hg/store
|
|
|
* `hardlink`: use a hardlink to quickly create the backup
|
|
|
"""
|
|
|
if self._queue:
|
|
|
msg = 'cannot use transaction.addbackup inside "group"'
|
|
|
raise RuntimeError(msg)
|
|
|
|
|
|
if file in self.map or file in self._backupmap:
|
|
|
return
|
|
|
vfs = self._vfsmap[location]
|
|
|
dirname, filename = vfs.split(file)
|
|
|
backupfilename = "%s.backup.%s" % (self.journal, filename)
|
|
|
backupfile = vfs.reljoin(dirname, backupfilename)
|
|
|
if vfs.exists(file):
|
|
|
filepath = vfs.join(file)
|
|
|
backuppath = vfs.join(backupfile)
|
|
|
util.copyfile(filepath, backuppath, hardlink=hardlink)
|
|
|
else:
|
|
|
backupfile = ''
|
|
|
|
|
|
self._addbackupentry((location, file, backupfile, False))
|
|
|
|
|
|
def _addbackupentry(self, entry):
|
|
|
"""register a new backup entry and write it to disk"""
|
|
|
self._backupentries.append(entry)
|
|
|
self._backupmap[file] = len(self._backupentries) - 1
|
|
|
self._backupsfile.write("%s\0%s\0%s\0%d\n" % entry)
|
|
|
self._backupsfile.flush()
|
|
|
|
|
|
@active
|
|
|
def registertmp(self, tmpfile, location=''):
|
|
|
"""register a temporary transaction file
|
|
|
|
|
|
Such files will be deleted when the transaction exits (on both
|
|
|
failure and success).
|
|
|
"""
|
|
|
self._addbackupentry((location, '', tmpfile, False))
|
|
|
|
|
|
@active
|
|
|
def addfilegenerator(self, genid, filenames, genfunc, order=0,
|
|
|
location=''):
|
|
|
"""add a function to generates some files at transaction commit
|
|
|
|
|
|
The `genfunc` argument is a function capable of generating proper
|
|
|
content of each entry in the `filename` tuple.
|
|
|
|
|
|
At transaction close time, `genfunc` will be called with one file
|
|
|
object argument per entries in `filenames`.
|
|
|
|
|
|
The transaction itself is responsible for the backup, creation and
|
|
|
final write of such file.
|
|
|
|
|
|
The `genid` argument is used to ensure the same set of file is only
|
|
|
generated once. Call to `addfilegenerator` for a `genid` already
|
|
|
present will overwrite the old entry.
|
|
|
|
|
|
The `order` argument may be used to control the order in which multiple
|
|
|
generator will be executed.
|
|
|
|
|
|
The `location` arguments may be used to indicate the files are located
|
|
|
outside of the the standard directory for transaction. It should match
|
|
|
one of the key of the `transaction.vfsmap` dictionary.
|
|
|
"""
|
|
|
# For now, we are unable to do proper backup and restore of custom vfs
|
|
|
# but for bookmarks that are handled outside this mechanism.
|
|
|
self._filegenerators[genid] = (order, filenames, genfunc, location)
|
|
|
|
|
|
def _generatefiles(self, suffix=''):
|
|
|
# write files registered for generation
|
|
|
any = False
|
|
|
for entry in sorted(self._filegenerators.values()):
|
|
|
any = True
|
|
|
order, filenames, genfunc, location = entry
|
|
|
vfs = self._vfsmap[location]
|
|
|
files = []
|
|
|
try:
|
|
|
for name in filenames:
|
|
|
name += suffix
|
|
|
if suffix:
|
|
|
self.registertmp(name, location=location)
|
|
|
else:
|
|
|
self.addbackup(name, location=location)
|
|
|
files.append(vfs(name, 'w', atomictemp=True))
|
|
|
genfunc(*files)
|
|
|
finally:
|
|
|
for f in files:
|
|
|
f.close()
|
|
|
return any
|
|
|
|
|
|
@active
|
|
|
def find(self, file):
|
|
|
if file in self.map:
|
|
|
return self.entries[self.map[file]]
|
|
|
if file in self._backupmap:
|
|
|
return self._backupentries[self._backupmap[file]]
|
|
|
return None
|
|
|
|
|
|
@active
|
|
|
def replace(self, file, offset, data=None):
|
|
|
'''
|
|
|
replace can only replace already committed entries
|
|
|
that are not pending in the queue
|
|
|
'''
|
|
|
|
|
|
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()
|
|
|
|
|
|
@active
|
|
|
def nest(self):
|
|
|
self.count += 1
|
|
|
self.usages += 1
|
|
|
return self
|
|
|
|
|
|
def release(self):
|
|
|
if self.count > 0:
|
|
|
self.usages -= 1
|
|
|
# if the transaction scopes are left without being closed, fail
|
|
|
if self.count > 0 and self.usages == 0:
|
|
|
self._abort()
|
|
|
|
|
|
def running(self):
|
|
|
return self.count > 0
|
|
|
|
|
|
def addpending(self, category, callback):
|
|
|
"""add a callback to be called when the transaction is pending
|
|
|
|
|
|
The transaction will be given as callback's first argument.
|
|
|
|
|
|
Category is a unique identifier to allow overwriting an old callback
|
|
|
with a newer callback.
|
|
|
"""
|
|
|
self._pendingcallback[category] = callback
|
|
|
|
|
|
@active
|
|
|
def writepending(self):
|
|
|
'''write pending file to temporary version
|
|
|
|
|
|
This is used to allow hooks to view a transaction before commit'''
|
|
|
categories = sorted(self._pendingcallback)
|
|
|
for cat in categories:
|
|
|
# remove callback since the data will have been flushed
|
|
|
any = self._pendingcallback.pop(cat)(self)
|
|
|
self._anypending = self._anypending or any
|
|
|
self._anypending |= self._generatefiles(suffix='.pending')
|
|
|
return self._anypending
|
|
|
|
|
|
@active
|
|
|
def addfinalize(self, category, callback):
|
|
|
"""add a callback to be called when the transaction is closed
|
|
|
|
|
|
The transaction will be given as callback's first argument.
|
|
|
|
|
|
Category is a unique identifier to allow overwriting old callbacks with
|
|
|
newer callbacks.
|
|
|
"""
|
|
|
self._finalizecallback[category] = callback
|
|
|
|
|
|
@active
|
|
|
def addpostclose(self, category, callback):
|
|
|
"""add a callback to be called after the transaction is closed
|
|
|
|
|
|
The transaction will be given as callback's first argument.
|
|
|
|
|
|
Category is a unique identifier to allow overwriting an old callback
|
|
|
with a newer callback.
|
|
|
"""
|
|
|
self._postclosecallback[category] = callback
|
|
|
|
|
|
@active
|
|
|
def addabort(self, category, callback):
|
|
|
"""add a callback to be called when the transaction is aborted.
|
|
|
|
|
|
The transaction will be given as the first argument to the callback.
|
|
|
|
|
|
Category is a unique identifier to allow overwriting an old callback
|
|
|
with a newer callback.
|
|
|
"""
|
|
|
self._abortcallback[category] = callback
|
|
|
|
|
|
@active
|
|
|
def close(self):
|
|
|
'''commit the transaction'''
|
|
|
if self.count == 1:
|
|
|
self.validator(self) # will raise exception if needed
|
|
|
self._generatefiles()
|
|
|
categories = sorted(self._finalizecallback)
|
|
|
for cat in categories:
|
|
|
self._finalizecallback[cat](self)
|
|
|
|
|
|
self.count -= 1
|
|
|
if self.count != 0:
|
|
|
return
|
|
|
self.file.close()
|
|
|
self._backupsfile.close()
|
|
|
# cleanup temporary files
|
|
|
for l, f, b, c in self._backupentries:
|
|
|
if l not in self._vfsmap and c:
|
|
|
self.report("couldn't remote %s: unknown cache location %s\n"
|
|
|
% (b, l))
|
|
|
continue
|
|
|
vfs = self._vfsmap[l]
|
|
|
if not f and b and vfs.exists(b):
|
|
|
try:
|
|
|
vfs.unlink(b)
|
|
|
except (IOError, OSError, util.Abort), inst:
|
|
|
if not c:
|
|
|
raise
|
|
|
# Abort may be raise by read only opener
|
|
|
self.report("couldn't remote %s: %s\n"
|
|
|
% (vfs.join(b), inst))
|
|
|
self.entries = []
|
|
|
self._writeundo()
|
|
|
if self.after:
|
|
|
self.after()
|
|
|
if self.opener.isfile(self.journal):
|
|
|
self.opener.unlink(self.journal)
|
|
|
if self.opener.isfile(self._backupjournal):
|
|
|
self.opener.unlink(self._backupjournal)
|
|
|
for l, _f, b, c in self._backupentries:
|
|
|
if l not in self._vfsmap and c:
|
|
|
self.report("couldn't remote %s: unknown cache location"
|
|
|
"%s\n" % (b, l))
|
|
|
continue
|
|
|
vfs = self._vfsmap[l]
|
|
|
if b and vfs.exists(b):
|
|
|
try:
|
|
|
vfs.unlink(b)
|
|
|
except (IOError, OSError, util.Abort), inst:
|
|
|
if not c:
|
|
|
raise
|
|
|
# Abort may be raise by read only opener
|
|
|
self.report("couldn't remote %s: %s\n"
|
|
|
% (vfs.join(b), inst))
|
|
|
self._backupentries = []
|
|
|
self.journal = None
|
|
|
# run post close action
|
|
|
categories = sorted(self._postclosecallback)
|
|
|
for cat in categories:
|
|
|
self._postclosecallback[cat](self)
|
|
|
|
|
|
@active
|
|
|
def abort(self):
|
|
|
'''abort the transaction (generally called on error, or when the
|
|
|
transaction is not explicitly committed before going out of
|
|
|
scope)'''
|
|
|
self._abort()
|
|
|
|
|
|
def _writeundo(self):
|
|
|
"""write transaction data for possible future undo call"""
|
|
|
if self.undoname is None:
|
|
|
return
|
|
|
undobackupfile = self.opener.open("%s.backupfiles" % self.undoname, 'w')
|
|
|
undobackupfile.write('%d\n' % version)
|
|
|
for l, f, b, c in self._backupentries:
|
|
|
if not f: # temporary file
|
|
|
continue
|
|
|
if not b:
|
|
|
u = ''
|
|
|
else:
|
|
|
if l not in self._vfsmap and c:
|
|
|
self.report("couldn't remote %s: unknown cache location"
|
|
|
"%s\n" % (b, l))
|
|
|
continue
|
|
|
vfs = self._vfsmap[l]
|
|
|
base, name = vfs.split(b)
|
|
|
assert name.startswith(self.journal), name
|
|
|
uname = name.replace(self.journal, self.undoname, 1)
|
|
|
u = vfs.reljoin(base, uname)
|
|
|
util.copyfile(vfs.join(b), vfs.join(u), hardlink=True)
|
|
|
undobackupfile.write("%s\0%s\0%s\0%d\n" % (l, f, u, c))
|
|
|
undobackupfile.close()
|
|
|
|
|
|
|
|
|
def _abort(self):
|
|
|
self.count = 0
|
|
|
self.usages = 0
|
|
|
self.file.close()
|
|
|
self._backupsfile.close()
|
|
|
|
|
|
try:
|
|
|
if not self.entries and not self._backupentries:
|
|
|
if self.journal:
|
|
|
self.opener.unlink(self.journal)
|
|
|
if self._backupjournal:
|
|
|
self.opener.unlink(self._backupjournal)
|
|
|
return
|
|
|
|
|
|
self.report(_("transaction abort!\n"))
|
|
|
|
|
|
try:
|
|
|
for cat in sorted(self._abortcallback):
|
|
|
self._abortcallback[cat](self)
|
|
|
_playback(self.journal, self.report, self.opener, self._vfsmap,
|
|
|
self.entries, self._backupentries, False)
|
|
|
self.report(_("rollback completed\n"))
|
|
|
except Exception:
|
|
|
self.report(_("rollback failed - please run hg recover\n"))
|
|
|
finally:
|
|
|
self.journal = None
|
|
|
|
|
|
|
|
|
def rollback(opener, vfsmap, file, report):
|
|
|
"""Rolls back the transaction contained in the given file
|
|
|
|
|
|
Reads the entries in the specified file, and the corresponding
|
|
|
'*.backupfiles' file, to recover from an incomplete transaction.
|
|
|
|
|
|
* `file`: a file containing a list of entries, specifying where
|
|
|
to truncate each file. The file should contain a list of
|
|
|
file\0offset pairs, delimited by newlines. The corresponding
|
|
|
'*.backupfiles' file should contain a list of file\0backupfile
|
|
|
pairs, delimited by \0.
|
|
|
"""
|
|
|
entries = []
|
|
|
backupentries = []
|
|
|
|
|
|
fp = opener.open(file)
|
|
|
lines = fp.readlines()
|
|
|
fp.close()
|
|
|
for l in lines:
|
|
|
try:
|
|
|
f, o = l.split('\0')
|
|
|
entries.append((f, int(o), None))
|
|
|
except ValueError:
|
|
|
report(_("couldn't read journal entry %r!\n") % l)
|
|
|
|
|
|
backupjournal = "%s.backupfiles" % file
|
|
|
if opener.exists(backupjournal):
|
|
|
fp = opener.open(backupjournal)
|
|
|
lines = fp.readlines()
|
|
|
if lines:
|
|
|
ver = lines[0][:-1]
|
|
|
if ver == str(version):
|
|
|
for line in lines[1:]:
|
|
|
if line:
|
|
|
# Shave off the trailing newline
|
|
|
line = line[:-1]
|
|
|
l, f, b, c = line.split('\0')
|
|
|
backupentries.append((l, f, b, bool(c)))
|
|
|
else:
|
|
|
report(_("journal was created by a different version of "
|
|
|
"Mercurial\n"))
|
|
|
|
|
|
_playback(file, report, opener, vfsmap, entries, backupentries)
|
|
|
|
