Mercurial > public > mercurial-scm > hg-stable
comparison mercurial/util.py @ 15057:774da7121fc9
atomictempfile: make close() consistent with other file-like objects.
The usual contract is that close() makes your writes permanent, so
atomictempfile's use of close() to *discard* writes (and rename() to
keep them) is rather unexpected. Thus, change it so close() makes
things permanent and add a new discard() method to throw them away.
discard() is only used internally, in __del__(), to ensure that writes
are discarded when an atomictempfile object goes out of scope.
I audited mercurial.*, hgext.*, and ~80 third-party extensions, and
found no one using the existing semantics of close() to discard
writes, so this should be safe.
| author | Greg Ward <greg@gerg.ca> |
|---|---|
| date | Thu, 25 Aug 2011 20:21:04 -0400 |
| parents | ff3e93686306 |
| children | 81f33be0ea79 |
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| 15056:8413916df816 | 15057:774da7121fc9 |
|---|---|
| 743 | 743 |
| 744 class atomictempfile(object): | 744 class atomictempfile(object): |
| 745 '''writeable file object that atomically updates a file | 745 '''writeable file object that atomically updates a file |
| 746 | 746 |
| 747 All writes will go to a temporary copy of the original file. Call | 747 All writes will go to a temporary copy of the original file. Call |
| 748 rename() when you are done writing, and atomictempfile will rename | 748 close() when you are done writing, and atomictempfile will rename |
| 749 the temporary copy to the original name, making the changes visible. | 749 the temporary copy to the original name, making the changes |
| 750 | 750 visible. If the object is destroyed without being closed, all your |
| 751 Unlike other file-like objects, close() discards your writes by | 751 writes are discarded. |
| 752 simply deleting the temporary file. | |
| 753 ''' | 752 ''' |
| 754 def __init__(self, name, mode='w+b', createmode=None): | 753 def __init__(self, name, mode='w+b', createmode=None): |
| 755 self.__name = name # permanent name | 754 self.__name = name # permanent name |
| 756 self._tempname = mktempcopy(name, emptyok=('w' in mode), | 755 self._tempname = mktempcopy(name, emptyok=('w' in mode), |
| 757 createmode=createmode) | 756 createmode=createmode) |
| 759 | 758 |
| 760 # delegated methods | 759 # delegated methods |
| 761 self.write = self._fp.write | 760 self.write = self._fp.write |
| 762 self.fileno = self._fp.fileno | 761 self.fileno = self._fp.fileno |
| 763 | 762 |
| 764 def rename(self): | 763 def close(self): |
| 765 if not self._fp.closed: | 764 if not self._fp.closed: |
| 766 self._fp.close() | 765 self._fp.close() |
| 767 rename(self._tempname, localpath(self.__name)) | 766 rename(self._tempname, localpath(self.__name)) |
| 768 | 767 |
| 769 def close(self): | 768 def discard(self): |
| 770 if not self._fp.closed: | 769 if not self._fp.closed: |
| 771 try: | 770 try: |
| 772 os.unlink(self._tempname) | 771 os.unlink(self._tempname) |
| 773 except OSError: | 772 except OSError: |
| 774 pass | 773 pass |
| 775 self._fp.close() | 774 self._fp.close() |
| 776 | 775 |
| 777 def __del__(self): | 776 def __del__(self): |
| 778 if safehasattr(self, '_fp'): # constructor actually did something | 777 if safehasattr(self, '_fp'): # constructor actually did something |
| 779 self.close() | 778 self.discard() |
| 780 | 779 |
| 781 def makedirs(name, mode=None): | 780 def makedirs(name, mode=None): |
| 782 """recursive directory creation with parent mode inheritance""" | 781 """recursive directory creation with parent mode inheritance""" |
| 783 parent = os.path.abspath(os.path.dirname(name)) | 782 parent = os.path.abspath(os.path.dirname(name)) |
| 784 try: | 783 try: |