mirror of
https://github.com/kovidgoyal/calibre.git
synced 2025-07-08 18:54:09 -04:00
Improve implementation of lopen()
Greatly simplify window implementation. Reduce the average number of system calls used per invocation on OS X and linux.
This commit is contained in:
Kovid Goyal
parent
ae6bac5159
commit
40d4224363
@ -6,7 +6,7 @@ __docformat__ = 'restructuredtext en'
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Perform various initialization tasks.
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'''
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import locale, sys, os, re
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import locale, sys
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# Default translation is NOOP
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import __builtin__
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@ -109,97 +109,40 @@ if not _run_once:
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except:
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pass
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#
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def local_open(name, mode='r', bufsize=-1):
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'''
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Open a file that wont be inherited by child processes
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Only supports the following modes:
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r, w, a, rb, wb, ab, r+, w+, a+, r+b, w+b, a+b
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'''
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if iswindows:
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class fwrapper(object):
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def __init__(self, name, fobject):
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object.__setattr__(self, 'fobject', fobject)
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object.__setattr__(self, 'name', name)
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def __getattribute__(self, attr):
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if attr in ('name', '__enter__', '__str__', '__unicode__',
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'__repr__', '__exit__'):
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return object.__getattribute__(self, attr)
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fobject = object.__getattribute__(self, 'fobject')
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return getattr(fobject, attr)
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def __setattr__(self, attr, val):
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fobject = object.__getattribute__(self, 'fobject')
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return setattr(fobject, attr, val)
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def __repr__(self):
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fobject = object.__getattribute__(self, 'fobject')
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name = object.__getattribute__(self, 'name')
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return re.sub(r'''['"]<fdopen>['"]''', repr(name),
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repr(fobject))
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def __str__(self):
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return repr(self)
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def __unicode__(self):
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return repr(self).decode('utf-8')
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def __enter__(self):
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fobject = object.__getattribute__(self, 'fobject')
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fobject.__enter__()
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return self
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def __exit__(self, *args):
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fobject = object.__getattribute__(self, 'fobject')
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return fobject.__exit__(*args)
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m = mode[0]
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random = len(mode) > 1 and mode[1] == '+'
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binary = mode[-1] == 'b'
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if m == 'a':
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flags = os.O_APPEND| os.O_RDWR
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flags |= os.O_RANDOM if random else os.O_SEQUENTIAL
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elif m == 'r':
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if random:
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flags = os.O_RDWR | os.O_RANDOM
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else:
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flags = os.O_RDONLY | os.O_SEQUENTIAL
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elif m == 'w':
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if random:
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flags = os.O_RDWR | os.O_RANDOM
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else:
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flags = os.O_WRONLY | os.O_SEQUENTIAL
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flags |= os.O_TRUNC | os.O_CREAT
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if binary:
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flags |= os.O_BINARY
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else:
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flags |= os.O_TEXT
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flags |= os.O_NOINHERIT
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fd = os.open(name, flags)
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ans = os.fdopen(fd, mode, bufsize)
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ans = fwrapper(name, ans)
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else:
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import fcntl
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try:
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cloexec_flag = fcntl.FD_CLOEXEC
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except AttributeError:
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cloexec_flag = 1
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# Python 2.x uses fopen which on recent glibc/linux kernel at least
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# respects the 'e' mode flag. On OS X the e is ignored. So to try
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# to get atomicity where possible we pass 'e' and then only use
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# fcntl only if CLOEXEC was not set.
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if islinux:
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mode += 'e'
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# local_open() opens a file that wont be inherited by child processes
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if iswindows:
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def local_open(name, mode='r', bufsize=-1):
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mode += 'N'
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return open(name, mode, bufsize)
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elif isosx:
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import fcntl
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FIOCLEX = 0x20006601
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def local_open(name, mode='r', bufsize=-1):
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ans = open(name, mode, bufsize)
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try:
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fcntl.ioctl(ans.fileno(), FIOCLEX)
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except EnvironmentError:
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fcntl.fcntl(ans, fcntl.F_SETFD, fcntl.fcntl(ans, fcntl.F_GETFD) | fcntl.FD_CLOEXEC)
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return ans
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else:
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import fcntl
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try:
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cloexec_flag = fcntl.FD_CLOEXEC
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except AttributeError:
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cloexec_flag = 1
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supports_mode_e = False
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def local_open(name, mode='r', bufsize=-1):
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global supports_mode_e
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mode += 'e'
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ans = open(name, mode, bufsize)
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if supports_mode_e:
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return ans
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old = fcntl.fcntl(ans, fcntl.F_GETFD)
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if not (old & cloexec_flag):
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fcntl.fcntl(ans, fcntl.F_SETFD, old | cloexec_flag)
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return ans
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else:
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supports_mode_e = True
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return ans
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__builtin__.__dict__['lopen'] = local_open
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@ -242,34 +185,47 @@ def test_lopen():
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from calibre.ptempfile import TemporaryDirectory
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from calibre import CurrentDir
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n = u'f\xe4llen'
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print('testing lopen()')
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with TemporaryDirectory() as tdir:
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with CurrentDir(tdir):
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with lopen(n, 'w') as f:
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f.write('one')
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print 'O_CREAT tested'
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with lopen(n, 'w+b') as f:
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f.write('two')
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with lopen(n, 'r') as f:
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if f.read() == 'two':
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print 'O_TRUNC tested'
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else:
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raise Exception('O_TRUNC failed')
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with lopen(n, 'ab') as f:
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f.write('three')
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with lopen(n, 'r+') as f:
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if f.read() == 'twothree':
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print 'O_APPEND tested'
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else:
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raise Exception('O_APPEND failed')
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with lopen(n, 'r+') as f:
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f.seek(3)
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f.write('xxxxx')
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f.seek(0)
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if f.read() == 'twoxxxxx':
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print 'O_RANDOM tested'
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else:
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raise Exception('O_RANDOM failed')
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if iswindows:
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import msvcrt, win32api
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def assert_not_inheritable(f):
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if win32api.GetHandleInformation(msvcrt.get_osfhandle(f.fileno())) & 0b1:
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raise SystemExit('File handle is inheritable!')
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else:
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def assert_not_inheritable(f):
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if not fcntl.fcntl(f, fcntl.F_GETFD) & fcntl.FD_CLOEXEC:
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raise SystemExit('File handle is inheritable!')
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def copen(*args):
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ans = lopen(*args)
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assert_not_inheritable(ans)
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return ans
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with TemporaryDirectory() as tdir, CurrentDir(tdir):
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with copen(n, 'w') as f:
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f.write('one')
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print 'O_CREAT tested'
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with copen(n, 'w+b') as f:
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f.write('two')
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with copen(n, 'r') as f:
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if f.read() == 'two':
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print 'O_TRUNC tested'
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else:
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raise Exception('O_TRUNC failed')
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with copen(n, 'ab') as f:
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f.write('three')
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with copen(n, 'r+') as f:
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if f.read() == 'twothree':
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print 'O_APPEND tested'
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else:
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raise Exception('O_APPEND failed')
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with copen(n, 'r+') as f:
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f.seek(3)
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f.write('xxxxx')
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f.seek(0)
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if f.read() == 'twoxxxxx':
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print 'O_RANDOM tested'
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else:
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raise Exception('O_RANDOM failed')
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