def demo():
"""
Definition of buffer used with FSCTL_TXFS_CREATE_MINIVERSION:
typedef struct _TXFS_CREATE_MINIVERSION_INFO{
USHORT StructureVersion;
USHORT StructureLength;
ULONG BaseVersion;
USHORT MiniVersion;}
"""
buf_fmt='HHLH0L' ## buffer size must include struct padding
buf_size=struct.calcsize(buf_fmt)
tempdir=win32api.GetTempPath()
tempfile=win32api.GetTempFileName(tempdir,'cft')[0]
print("Demonstrating transactions on tempfile", tempfile)
f=open(tempfile,'w')
f.write('This is original file.\n')
f.close()
trans=win32transaction.CreateTransaction(Description='Test creating miniversions of a file')
hfile=win32file.CreateFileW(tempfile, win32con.GENERIC_READ|win32con.GENERIC_WRITE,
win32con.FILE_SHARE_READ|win32con.FILE_SHARE_WRITE,
None, win32con.OPEN_EXISTING, 0 , None, Transaction=trans)
win32file.WriteFile(hfile, str2bytes('This is first miniversion.\n'))
buf=win32file.DeviceIoControl(hfile, winioctlcon.FSCTL_TXFS_CREATE_MINIVERSION,None,buf_size,None)
struct_ver, struct_len, base_ver, ver_1=struct.unpack(buf_fmt, buf)
win32file.SetFilePointer(hfile, 0, win32con.FILE_BEGIN)
win32file.WriteFile(hfile, str2bytes('This is second miniversion!\n'))
buf=win32file.DeviceIoControl(hfile, winioctlcon.FSCTL_TXFS_CREATE_MINIVERSION,None,buf_size,None)
struct_ver, struct_len, base_ver, ver_2=struct.unpack(buf_fmt, buf)
hfile.Close()
## miniversions can't be opened with write access
hfile_0=win32file.CreateFileW(tempfile, win32con.GENERIC_READ,
win32con.FILE_SHARE_READ|win32con.FILE_SHARE_WRITE,
None, win32con.OPEN_EXISTING, 0 , None, Transaction=trans, MiniVersion=base_ver)
print('version:',base_ver,win32file.ReadFile(hfile_0, 100))
hfile_0.Close()
hfile_1=win32file.CreateFileW(tempfile, win32con.GENERIC_READ,
win32con.FILE_SHARE_READ|win32con.FILE_SHARE_WRITE,
None, win32con.OPEN_EXISTING, 0 , None, Transaction=trans, MiniVersion=ver_1)
print('version:',ver_1,win32file.ReadFile(hfile_1, 100))
hfile_1.Close()
hfile_2=win32file.CreateFileW(tempfile, win32con.GENERIC_READ,
win32con.FILE_SHARE_READ|win32con.FILE_SHARE_WRITE,
None, win32con.OPEN_EXISTING, 0 , None, Transaction=trans, MiniVersion=ver_2)
print('version:',ver_2,win32file.ReadFile(hfile_2, 100))
hfile_2.Close()
## MiniVersions are destroyed when transaction is committed or rolled back
win32transaction.CommitTransaction(trans)
os.unlink(tempfile)
hfile_0.Close()
hfile_1 = win32file.CreateFileW(tempfile,
win32con.GENERIC_READ,
win32con.FILE_SHARE_READ
| win32con.FILE_SHARE_WRITE,
None,
win32con.OPEN_EXISTING,
0,
None,
Transaction=trans,
MiniVersion=ver_1)
print 'version:', ver_1, win32file.ReadFile(hfile_1, 100)
hfile_1.Close()
hfile_2 = win32file.CreateFileW(tempfile,
win32con.GENERIC_READ,
win32con.FILE_SHARE_READ
| win32con.FILE_SHARE_WRITE,
None,
win32con.OPEN_EXISTING,
0,
None,
Transaction=trans,
MiniVersion=ver_2)
print 'version:', ver_2, win32file.ReadFile(hfile_2, 100)
hfile_2.Close()
## MiniVersions are destroyed when transaction is committed or rolled back
win32transaction.CommitTransaction(trans)
## reopen key in transacted mode
transacted_key=win32api.RegOpenKeyTransacted(Key=win32con.HKEY_CURRENT_USER, SubKey=keyname,
Transaction=trans, samDesired=win32con.KEY_ALL_ACCESS)
subkey, disp=win32api.RegCreateKeyEx(transacted_key, subkeyname, Transaction=trans,
samDesired=win32con.KEY_ALL_ACCESS, Class=classname)
## Newly created key should not be visible from non-transacted handle
subkeys=[s[0] for s in win32api.RegEnumKeyExW(key)]
assert subkeyname not in subkeys
transacted_subkeys=[s[0] for s in win32api.RegEnumKeyExW(transacted_key)]
assert subkeyname in transacted_subkeys
## Key should be visible to non-transacted handle after commit
win32transaction.CommitTransaction(trans)
subkeys=[s[0] for s in win32api.RegEnumKeyExW(key)]
assert subkeyname in subkeys
## test transacted delete
del_trans=win32transaction.CreateTransaction(Description='test RegDeleteKeyTransacted')
win32api.RegDeleteKeyEx(key, subkeyname, Transaction=del_trans)
## subkey should still show up for non-transacted handle
subkeys=[s[0] for s in win32api.RegEnumKeyExW(key)]
assert subkeyname in subkeys
## ... and should be gone after commit
win32transaction.CommitTransaction(del_trans)
subkeys=[s[0] for s in win32api.RegEnumKeyExW(key)]
assert subkeyname not in subkeys
win32api.RegDeleteKey(win32con.HKEY_CURRENT_USER, keyname)