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cmdutil: add class to restore dirstate during unexpected failure...
cmdutil: add class to restore dirstate during unexpected failure Before this patch, after "dirstate.write()" execution, there was no way to restore dirstate to the original status before "dirstate.write()". In some code paths, "dirstate.invalidate()" is used as a kind of "restore .hg/dirstate to the original status", but it just avoids writing changes in memory out, and doesn't actually restore the ".hg/dirstate" file. To fix the issue that the recent (in memory) dirstate isn't visible to external processes (e.g. "precommit" hooks), "dirstate.write()" should be invoked before invocation of external processes. But at the same time, ".hg/dirstate" should be restored to its content before "dirstate.write()" during an unexpected failure in some cases. This patch adds the class "dirstateguard" to easily restore ".hg/dirstate" during unexpected failures. Typical usecase of it is: # (1) build dirstate up .... # (2) write dirstate out, and backup ".hg/dirstate" dsguard = dirstateguard(repo, 'scopename') try: # (3) execute somethig to do: # this may imply making some additional changes on dirstate .... # (4) unlink backed-up dirstate file at the end of dsguard scope dsguard.close() finally: # (5) if execution is aborted before "dsguard.close()", # ".hg/dirstate" is restored from the backup dsguard.release() For this kind of issue, an "extending transaction" approach (in https://titanpad.com/mercurial32-sprint) seems to not be suitable, because: - transaction nesting occurs in some cases (e.g. "shelve => rebase"), and - "dirstate" may be already modified since the beginning of OUTER transaction scope, then - dirstate should be backed up into the file other than "dirstate.journal" at the beginning of INNER transaction scope, but - such alternative backup files are useless for transaction itself, and increases complication of its implementation "transaction" and "dirstateguard" differ from each other also in "what it should do for .hg/dirstate" in cases other than success. ============== ======= ======== ============= type success fail "hg rollback" ============== ======= ======== ============= transaction keep keep restore dirstateguard keep restore (not implied) ============== ======= ======== ============= Some collaboration between transaction and dirstate will probably be introduced in the future. But this layer is needed in all cases.

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r22993:24c5fd28 default
r24991:4169a4f8 default
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hgclient.py
109 lines | 3.1 KiB | text/x-python | PythonLexer
Yuya Nishihara
test-commandserver: split helper functions to new hgclient module...
r22566 # A minimal client for Mercurial's command server
Yuya Nishihara
test-commandserver: add connector for unix domain socket server...
r22993 import os, sys, signal, struct, socket, subprocess, time, cStringIO
Yuya Nishihara
test-commandserver: split helper functions to new hgclient module...
r22566
Yuya Nishihara
test-commandserver: allow check() to make connection in different way...
r22992 def connectpipe(path=None):
Yuya Nishihara
test-commandserver: split helper functions to new hgclient module...
r22566 cmdline = ['hg', 'serve', '--cmdserver', 'pipe']
if path:
cmdline += ['-R', path]
server = subprocess.Popen(cmdline, stdin=subprocess.PIPE,
stdout=subprocess.PIPE)
return server
Yuya Nishihara
test-commandserver: add connector for unix domain socket server...
r22993 class unixconnection(object):
def __init__(self, sockpath):
self.sock = sock = socket.socket(socket.AF_UNIX)
sock.connect(sockpath)
self.stdin = sock.makefile('wb')
self.stdout = sock.makefile('rb')
def wait(self):
self.stdin.close()
self.stdout.close()
self.sock.close()
class unixserver(object):
def __init__(self, sockpath, logpath=None, repopath=None):
self.sockpath = sockpath
cmdline = ['hg', 'serve', '--cmdserver', 'unix', '-a', sockpath]
if repopath:
cmdline += ['-R', repopath]
if logpath:
stdout = open(logpath, 'a')
stderr = subprocess.STDOUT
else:
stdout = stderr = None
self.server = subprocess.Popen(cmdline, stdout=stdout, stderr=stderr)
# wait for listen()
while self.server.poll() is None:
if os.path.exists(sockpath):
break
time.sleep(0.1)
def connect(self):
return unixconnection(self.sockpath)
def shutdown(self):
os.kill(self.server.pid, signal.SIGTERM)
self.server.wait()
Yuya Nishihara
test-commandserver: split helper functions to new hgclient module...
r22566 def writeblock(server, data):
server.stdin.write(struct.pack('>I', len(data)))
server.stdin.write(data)
server.stdin.flush()
def readchannel(server):
data = server.stdout.read(5)
if not data:
raise EOFError
channel, length = struct.unpack('>cI', data)
if channel in 'IL':
return channel, length
else:
return channel, server.stdout.read(length)
def sep(text):
return text.replace('\\', '/')
def runcommand(server, args, output=sys.stdout, error=sys.stderr, input=None,
outfilter=lambda x: x):
Yuya Nishihara
test-commandserver: make runcommand message bolder...
r22572 print '*** runcommand', ' '.join(args)
Yuya Nishihara
test-commandserver: split helper functions to new hgclient module...
r22566 sys.stdout.flush()
server.stdin.write('runcommand\n')
writeblock(server, '\0'.join(args))
if not input:
input = cStringIO.StringIO()
while True:
ch, data = readchannel(server)
if ch == 'o':
output.write(outfilter(data))
output.flush()
elif ch == 'e':
error.write(data)
error.flush()
elif ch == 'I':
writeblock(server, input.read(data))
elif ch == 'L':
writeblock(server, input.readline(data))
elif ch == 'r':
ret, = struct.unpack('>i', data)
if ret != 0:
print ' [%d]' % ret
return ret
else:
print "unexpected channel %c: %r" % (ch, data)
if ch.isupper():
return
Yuya Nishihara
test-commandserver: allow check() to make connection in different way...
r22992 def check(func, connect=connectpipe):
Yuya Nishihara
test-commandserver: split helper functions to new hgclient module...
r22566 sys.stdout.flush()
Yuya Nishihara
test-commandserver: remove unused repopath argument from check()...
r22991 server = connect()
Yuya Nishihara
test-commandserver: split helper functions to new hgclient module...
r22566 try:
return func(server)
finally:
server.stdin.close()
server.wait()