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  • Committer: John Arbash Meinel
  • Date: 2009-06-02 19:56:24 UTC
  • mto: This revision was merged to the branch mainline in revision 4469.
  • Revision ID: john@arbash-meinel.com-20090602195624-utljsyz0qgmq63lg
Add a chunks_to_gzip function.
This allows the _record_to_data code to build up a list of chunks,
rather than requiring a single string.
It should be ~ the same performance when using a single string, since
we are only adding a for() loop over the chunks and an if check.
We could possibly just remove the if check and not worry about adding
some empty strings in there.

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bzrlib/lock.py
1
 
# Copyright (C) 2005-2010 Canonical Ltd
 
1
# Copyright (C) 2005, 2006, 2007, 2008, 2009 Canonical Ltd
2
2
#
3
3
# This program is free software; you can redistribute it and/or modify
4
4
# it under the terms of the GNU General Public License as published by
35
35
"""
36
36
 
37
37
import errno
38
 
import os
39
38
import sys
40
 
import warnings
41
39
 
42
40
from bzrlib import (
43
 
    debug,
44
41
    errors,
45
42
    osutils,
46
43
    trace,
84
81
        return self.lock_url == other.lock_url and self.details == other.details
85
82
 
86
83
    def __repr__(self):
87
 
        return '%s(%s, %s)' % (self.__class__.__name__,
 
84
        return '%s(%s%s)' % (self.__class__.__name__,
88
85
                             self.lock_url, self.details)
89
86
 
90
87
 
91
 
class LogicalLockResult(object):
92
 
    """The result of a lock_read/lock_write/lock_tree_write call on lockables.
93
 
 
94
 
    :ivar unlock: A callable which will unlock the lock.
95
 
    """
96
 
 
97
 
    def __init__(self, unlock):
98
 
        self.unlock = unlock
99
 
 
100
 
    def __repr__(self):
101
 
        return "LogicalLockResult(%s)" % (self.unlock)
102
 
 
103
 
 
104
 
 
105
 
def cant_unlock_not_held(locked_object):
106
 
    """An attempt to unlock failed because the object was not locked.
107
 
 
108
 
    This provides a policy point from which we can generate either a warning 
109
 
    or an exception.
110
 
    """
111
 
    # This is typically masking some other error and called from a finally
112
 
    # block, so it's useful to have the option not to generate a new error
113
 
    # here.  You can use -Werror to make it fatal.  It should possibly also
114
 
    # raise LockNotHeld.
115
 
    if 'unlock' in debug.debug_flags:
116
 
        warnings.warn("%r is already unlocked" % (locked_object,),
117
 
            stacklevel=3)
118
 
    else:
119
 
        raise errors.LockNotHeld(locked_object)
120
 
 
121
 
 
122
88
try:
123
89
    import fcntl
124
90
    have_fcntl = True
130
96
if sys.platform == 'win32':
131
97
    import msvcrt
132
98
    try:
133
 
        import win32file, pywintypes, winerror
 
99
        import win32con, win32file, pywintypes, winerror
134
100
        have_pywin32 = True
135
101
    except ImportError:
136
102
        pass
185
151
 
186
152
 
187
153
if have_fcntl:
 
154
    LOCK_SH = fcntl.LOCK_SH
 
155
    LOCK_NB = fcntl.LOCK_NB
 
156
    lock_EX = fcntl.LOCK_EX
 
157
 
188
158
 
189
159
    class _fcntl_FileLock(_OSLock):
190
160
 
204
174
            if self.filename in _fcntl_WriteLock._open_locks:
205
175
                self._clear_f()
206
176
                raise errors.LockContention(self.filename)
207
 
            if self.filename in _fcntl_ReadLock._open_locks:
208
 
                if 'strict_locks' in debug.debug_flags:
209
 
                    self._clear_f()
210
 
                    raise errors.LockContention(self.filename)
211
 
                else:
212
 
                    trace.mutter('Write lock taken w/ an open read lock on: %s'
213
 
                                 % (self.filename,))
214
177
 
215
178
            self._open(self.filename, 'rb+')
216
179
            # reserve a slot for this lock - even if the lockf call fails,
217
 
            # at this point unlock() will be called, because self.f is set.
 
180
            # at thisi point unlock() will be called, because self.f is set.
218
181
            # TODO: make this fully threadsafe, if we decide we care.
219
182
            _fcntl_WriteLock._open_locks.add(self.filename)
220
183
            try:
241
204
        def __init__(self, filename):
242
205
            super(_fcntl_ReadLock, self).__init__()
243
206
            self.filename = osutils.realpath(filename)
244
 
            if self.filename in _fcntl_WriteLock._open_locks:
245
 
                if 'strict_locks' in debug.debug_flags:
246
 
                    # We raise before calling _open so we don't need to
247
 
                    # _clear_f
248
 
                    raise errors.LockContention(self.filename)
249
 
                else:
250
 
                    trace.mutter('Read lock taken w/ an open write lock on: %s'
251
 
                                 % (self.filename,))
252
207
            _fcntl_ReadLock._open_locks.setdefault(self.filename, 0)
253
208
            _fcntl_ReadLock._open_locks[self.filename] += 1
254
209
            self._open(filename, 'rb')
349
304
 
350
305
 
351
306
if have_pywin32 and sys.platform == 'win32':
352
 
    if os.path.supports_unicode_filenames:
353
 
        # for Windows NT/2K/XP/etc
354
 
        win32file_CreateFile = win32file.CreateFileW
355
 
    else:
356
 
        # for Windows 98
357
 
        win32file_CreateFile = win32file.CreateFile
 
307
    LOCK_SH = 0 # the default
 
308
    LOCK_EX = win32con.LOCKFILE_EXCLUSIVE_LOCK
 
309
    LOCK_NB = win32con.LOCKFILE_FAIL_IMMEDIATELY
 
310
 
358
311
 
359
312
    class _w32c_FileLock(_OSLock):
360
313
 
361
 
        def _open(self, filename, access, share, cflags, pymode):
362
 
            self.filename = osutils.realpath(filename)
 
314
        def _lock(self, filename, openmode, lockmode):
 
315
            self._open(filename, openmode)
 
316
 
 
317
            self.hfile = msvcrt.get_osfhandle(self.f.fileno())
 
318
            overlapped = pywintypes.OVERLAPPED()
363
319
            try:
364
 
                self._handle = win32file_CreateFile(filename, access, share,
365
 
                    None, win32file.OPEN_ALWAYS,
366
 
                    win32file.FILE_ATTRIBUTE_NORMAL, None)
 
320
                win32file.LockFileEx(self.hfile, lockmode, 0, 0x7fff0000,
 
321
                                     overlapped)
367
322
            except pywintypes.error, e:
368
 
                if e.args[0] == winerror.ERROR_ACCESS_DENIED:
369
 
                    raise errors.LockFailed(filename, e)
370
 
                if e.args[0] == winerror.ERROR_SHARING_VIOLATION:
371
 
                    raise errors.LockContention(filename, e)
 
323
                self._clear_f()
 
324
                if e.args[0] in (winerror.ERROR_LOCK_VIOLATION,):
 
325
                    raise errors.LockContention(filename)
 
326
                ## import pdb; pdb.set_trace()
372
327
                raise
373
 
            fd = win32file._open_osfhandle(self._handle, cflags)
374
 
            self.f = os.fdopen(fd, pymode)
375
 
            return self.f
 
328
            except Exception, e:
 
329
                self._clear_f()
 
330
                raise errors.LockContention(filename, e)
376
331
 
377
332
        def unlock(self):
378
 
            self._clear_f()
379
 
            self._handle = None
 
333
            overlapped = pywintypes.OVERLAPPED()
 
334
            try:
 
335
                win32file.UnlockFileEx(self.hfile, 0, 0x7fff0000, overlapped)
 
336
                self._clear_f()
 
337
            except Exception, e:
 
338
                raise errors.LockContention(self.filename, e)
380
339
 
381
340
 
382
341
    class _w32c_ReadLock(_w32c_FileLock):
383
342
        def __init__(self, filename):
384
343
            super(_w32c_ReadLock, self).__init__()
385
 
            self._open(filename, win32file.GENERIC_READ,
386
 
                win32file.FILE_SHARE_READ, os.O_RDONLY, "rb")
 
344
            self._lock(filename, 'rb', LOCK_SH + LOCK_NB)
387
345
 
388
346
        def temporary_write_lock(self):
389
347
            """Try to grab a write lock on the file.
408
366
    class _w32c_WriteLock(_w32c_FileLock):
409
367
        def __init__(self, filename):
410
368
            super(_w32c_WriteLock, self).__init__()
411
 
            self._open(filename,
412
 
                win32file.GENERIC_READ | win32file.GENERIC_WRITE, 0,
413
 
                os.O_RDWR, "rb+")
 
369
            self._lock(filename, 'rb+', LOCK_EX + LOCK_NB)
414
370
 
415
371
        def restore_read_lock(self):
416
372
            """Restore the original ReadLock."""
424
380
 
425
381
 
426
382
if have_ctypes_win32:
427
 
    from ctypes.wintypes import DWORD, LPCSTR, LPCWSTR
428
 
    LPSECURITY_ATTRIBUTES = ctypes.c_void_p # used as NULL no need to declare
429
 
    HANDLE = ctypes.c_int # rather than unsigned as in ctypes.wintypes
430
 
    if os.path.supports_unicode_filenames:
431
 
        _function_name = "CreateFileW"
432
 
        LPTSTR = LPCWSTR
433
 
    else:
434
 
        _function_name = "CreateFileA"
435
 
        class LPTSTR(LPCSTR):
436
 
            def __new__(cls, obj):
437
 
                return LPCSTR.__new__(cls, obj.encode("mbcs"))
438
 
 
439
 
    # CreateFile <http://msdn.microsoft.com/en-us/library/aa363858.aspx>
440
 
    _CreateFile = ctypes.WINFUNCTYPE(
441
 
            HANDLE,                # return value
442
 
            LPTSTR,                # lpFileName
443
 
            DWORD,                 # dwDesiredAccess
444
 
            DWORD,                 # dwShareMode
445
 
            LPSECURITY_ATTRIBUTES, # lpSecurityAttributes
446
 
            DWORD,                 # dwCreationDisposition
447
 
            DWORD,                 # dwFlagsAndAttributes
448
 
            HANDLE                 # hTemplateFile
449
 
        )((_function_name, ctypes.windll.kernel32))
450
 
 
451
 
    INVALID_HANDLE_VALUE = -1
452
 
 
453
 
    GENERIC_READ = 0x80000000
454
 
    GENERIC_WRITE = 0x40000000
455
 
    FILE_SHARE_READ = 1
456
 
    OPEN_ALWAYS = 4
457
 
    FILE_ATTRIBUTE_NORMAL = 128
458
 
 
459
 
    ERROR_ACCESS_DENIED = 5
460
 
    ERROR_SHARING_VIOLATION = 32
 
383
    # These constants were copied from the win32con.py module.
 
384
    LOCKFILE_FAIL_IMMEDIATELY = 1
 
385
    LOCKFILE_EXCLUSIVE_LOCK = 2
 
386
    # Constant taken from winerror.py module
 
387
    ERROR_LOCK_VIOLATION = 33
 
388
 
 
389
    LOCK_SH = 0
 
390
    LOCK_EX = LOCKFILE_EXCLUSIVE_LOCK
 
391
    LOCK_NB = LOCKFILE_FAIL_IMMEDIATELY
 
392
    _LockFileEx = ctypes.windll.kernel32.LockFileEx
 
393
    _UnlockFileEx = ctypes.windll.kernel32.UnlockFileEx
 
394
    _GetLastError = ctypes.windll.kernel32.GetLastError
 
395
 
 
396
    ### Define the OVERLAPPED structure.
 
397
    #   http://msdn2.microsoft.com/en-us/library/ms684342.aspx
 
398
    # typedef struct _OVERLAPPED {
 
399
    #   ULONG_PTR Internal;
 
400
    #   ULONG_PTR InternalHigh;
 
401
    #   union {
 
402
    #     struct {
 
403
    #       DWORD Offset;
 
404
    #       DWORD OffsetHigh;
 
405
    #     };
 
406
    #     PVOID Pointer;
 
407
    #   };
 
408
    #   HANDLE hEvent;
 
409
    # } OVERLAPPED,
 
410
 
 
411
    class _inner_struct(ctypes.Structure):
 
412
        _fields_ = [('Offset', ctypes.c_uint), # DWORD
 
413
                    ('OffsetHigh', ctypes.c_uint), # DWORD
 
414
                   ]
 
415
 
 
416
    class _inner_union(ctypes.Union):
 
417
        _fields_  = [('anon_struct', _inner_struct), # struct
 
418
                     ('Pointer', ctypes.c_void_p), # PVOID
 
419
                    ]
 
420
 
 
421
    class OVERLAPPED(ctypes.Structure):
 
422
        _fields_ = [('Internal', ctypes.c_void_p), # ULONG_PTR
 
423
                    ('InternalHigh', ctypes.c_void_p), # ULONG_PTR
 
424
                    ('_inner_union', _inner_union),
 
425
                    ('hEvent', ctypes.c_void_p), # HANDLE
 
426
                   ]
461
427
 
462
428
    class _ctypes_FileLock(_OSLock):
463
429
 
464
 
        def _open(self, filename, access, share, cflags, pymode):
465
 
            self.filename = osutils.realpath(filename)
466
 
            handle = _CreateFile(filename, access, share, None, OPEN_ALWAYS,
467
 
                FILE_ATTRIBUTE_NORMAL, 0)
468
 
            if handle in (INVALID_HANDLE_VALUE, 0):
469
 
                e = ctypes.WinError()
470
 
                if e.args[0] == ERROR_ACCESS_DENIED:
471
 
                    raise errors.LockFailed(filename, e)
472
 
                if e.args[0] == ERROR_SHARING_VIOLATION:
473
 
                    raise errors.LockContention(filename, e)
474
 
                raise e
475
 
            fd = msvcrt.open_osfhandle(handle, cflags)
476
 
            self.f = os.fdopen(fd, pymode)
477
 
            return self.f
 
430
        def _lock(self, filename, openmode, lockmode):
 
431
            self._open(filename, openmode)
 
432
 
 
433
            self.hfile = msvcrt.get_osfhandle(self.f.fileno())
 
434
            overlapped = OVERLAPPED()
 
435
            result = _LockFileEx(self.hfile, # HANDLE hFile
 
436
                                 lockmode,   # DWORD dwFlags
 
437
                                 0,          # DWORD dwReserved
 
438
                                 0x7fffffff, # DWORD nNumberOfBytesToLockLow
 
439
                                 0x00000000, # DWORD nNumberOfBytesToLockHigh
 
440
                                 ctypes.byref(overlapped), # lpOverlapped
 
441
                                )
 
442
            if result == 0:
 
443
                self._clear_f()
 
444
                last_err = _GetLastError()
 
445
                if last_err in (ERROR_LOCK_VIOLATION,):
 
446
                    raise errors.LockContention(filename)
 
447
                raise errors.LockContention(filename,
 
448
                    'Unknown locking error: %s' % (last_err,))
478
449
 
479
450
        def unlock(self):
 
451
            overlapped = OVERLAPPED()
 
452
            result = _UnlockFileEx(self.hfile, # HANDLE hFile
 
453
                                   0,          # DWORD dwReserved
 
454
                                   0x7fffffff, # DWORD nNumberOfBytesToLockLow
 
455
                                   0x00000000, # DWORD nNumberOfBytesToLockHigh
 
456
                                   ctypes.byref(overlapped), # lpOverlapped
 
457
                                  )
480
458
            self._clear_f()
 
459
            if result == 0:
 
460
                self._clear_f()
 
461
                last_err = _GetLastError()
 
462
                raise errors.LockContention(self.filename,
 
463
                    'Unknown unlocking error: %s' % (last_err,))
481
464
 
482
465
 
483
466
    class _ctypes_ReadLock(_ctypes_FileLock):
484
467
        def __init__(self, filename):
485
468
            super(_ctypes_ReadLock, self).__init__()
486
 
            self._open(filename, GENERIC_READ, FILE_SHARE_READ, os.O_RDONLY,
487
 
                "rb")
 
469
            self._lock(filename, 'rb', LOCK_SH + LOCK_NB)
488
470
 
489
471
        def temporary_write_lock(self):
490
472
            """Try to grab a write lock on the file.
508
490
    class _ctypes_WriteLock(_ctypes_FileLock):
509
491
        def __init__(self, filename):
510
492
            super(_ctypes_WriteLock, self).__init__()
511
 
            self._open(filename, GENERIC_READ | GENERIC_WRITE, 0, os.O_RDWR,
512
 
                "rb+")
 
493
            self._lock(filename, 'rb+', LOCK_EX + LOCK_NB)
513
494
 
514
495
        def restore_read_lock(self):
515
496
            """Restore the original ReadLock."""
532
513
# We default to using the first available lock class.
533
514
_lock_type, WriteLock, ReadLock = _lock_classes[0]
534
515
 
535
 
 
536
 
class _RelockDebugMixin(object):
537
 
    """Mixin support for -Drelock flag.
538
 
 
539
 
    Add this as a base class then call self._note_lock with 'r' or 'w' when
540
 
    acquiring a read- or write-lock.  If this object was previously locked (and
541
 
    locked the same way), and -Drelock is set, then this will trace.note a
542
 
    message about it.
543
 
    """
544
 
    
545
 
    _prev_lock = None
546
 
 
547
 
    def _note_lock(self, lock_type):
548
 
        if 'relock' in debug.debug_flags and self._prev_lock == lock_type:
549
 
            if lock_type == 'r':
550
 
                type_name = 'read'
551
 
            else:
552
 
                type_name = 'write'
553
 
            trace.note('%r was %s locked again', self, type_name)
554
 
        self._prev_lock = lock_type
555