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109 lines
3.2 KiB
109 lines
3.2 KiB
5 years ago
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# Copyright (c) 2014-present PlatformIO <contact@platformio.org>
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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import os
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from time import sleep, time
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from platformio import exception
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LOCKFILE_TIMEOUT = 3600 # in seconds, 1 hour
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LOCKFILE_DELAY = 0.2
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LOCKFILE_INTERFACE_FCNTL = 1
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LOCKFILE_INTERFACE_MSVCRT = 2
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try:
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import fcntl
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LOCKFILE_CURRENT_INTERFACE = LOCKFILE_INTERFACE_FCNTL
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except ImportError:
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try:
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import msvcrt
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LOCKFILE_CURRENT_INTERFACE = LOCKFILE_INTERFACE_MSVCRT
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except ImportError:
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LOCKFILE_CURRENT_INTERFACE = None
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class LockFileExists(Exception):
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pass
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class LockFile(object):
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def __init__(self, path, timeout=LOCKFILE_TIMEOUT, delay=LOCKFILE_DELAY):
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self.timeout = timeout
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self.delay = delay
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self._lock_path = os.path.realpath(path) + ".lock"
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self._fp = None
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def _lock(self):
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if not LOCKFILE_CURRENT_INTERFACE and os.path.exists(self._lock_path):
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# remove stale lock
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if time() - os.path.getmtime(self._lock_path) > 10:
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try:
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os.remove(self._lock_path)
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except: # pylint: disable=bare-except
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pass
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else:
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raise LockFileExists
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self._fp = open(self._lock_path, "w")
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try:
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if LOCKFILE_CURRENT_INTERFACE == LOCKFILE_INTERFACE_FCNTL:
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fcntl.flock(self._fp.fileno(), fcntl.LOCK_EX | fcntl.LOCK_NB)
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elif LOCKFILE_CURRENT_INTERFACE == LOCKFILE_INTERFACE_MSVCRT:
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msvcrt.locking(self._fp.fileno(), msvcrt.LK_NBLCK, 1)
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except IOError:
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self._fp = None
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raise LockFileExists
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return True
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def _unlock(self):
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if not self._fp:
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return
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if LOCKFILE_CURRENT_INTERFACE == LOCKFILE_INTERFACE_FCNTL:
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fcntl.flock(self._fp.fileno(), fcntl.LOCK_UN)
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elif LOCKFILE_CURRENT_INTERFACE == LOCKFILE_INTERFACE_MSVCRT:
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msvcrt.locking(self._fp.fileno(), msvcrt.LK_UNLCK, 1)
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self._fp.close()
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self._fp = None
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def acquire(self):
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elapsed = 0
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while elapsed < self.timeout:
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try:
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return self._lock()
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except LockFileExists:
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sleep(self.delay)
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elapsed += self.delay
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raise exception.LockFileTimeoutError()
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def release(self):
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self._unlock()
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if os.path.exists(self._lock_path):
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try:
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os.remove(self._lock_path)
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except: # pylint: disable=bare-except
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pass
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def __enter__(self):
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self.acquire()
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def __exit__(self, type_, value, traceback):
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self.release()
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def __del__(self):
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self.release()
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