Fix deletion of locked files on Windows

bleachbit/FileUtilities.py

@@ -561,6 +561,13 @@ def sync():
         ctypes.cdll.LoadLibrary('msvcrt.dll')._flushall()
 
 
+def truncate_f(f):
+    """Truncate the file object"""
+    f.truncate(0)
+    f.flush()
+    os.fsync(f.fileno())
+
+
 def whitelisted_posix(path, check_realpath = True):
     """Check whether this POSIX path is whitelisted"""
     from bleachbit.Options import options
@@ -642,24 +649,31 @@ def wipe_write():
             file_wipe(path)
         except pywinerror as e:
             # 32=The process cannot access the file because it is being used by another process.
-            # 33=The process cannot access the file because another process has locked a portion of the file.
+            # 33=The process cannot access the file because another process has
+            # locked a portion of the file.
             if not e.winerror in (32, 33):
                 # handle only locking errors
                 raise
+            # Try to truncate the file. This makes the behavior consistent
+            # with Linux and with Windows when IsUserAdmin=False.
+            try:
+                with open(path, 'wb') as f:
+                    truncate_f(f)
+            except Exception as e2:
+                logger.exception('exception in truncate')
             # translate exception to mark file to deletion in Command.py
             raise WindowsError(e.winerror, e.strerror)
         except UnsupportedFileSystemError as e:
             warnings.warn(
                 _('At least one file was on a file system that does not support advanced overwriting.'), UserWarning)
             f = open(path, 'wb')
         else:
+            # The wipe succeed, so prepare to truncate.
             f = open(path, 'wb')
     else:
         f = wipe_write()
     if truncate:
-        f.truncate(0)
-        f.flush()
-        os.fsync(f.fileno())
+        truncate_f(f)
     f.close()
 
 
@@ -816,7 +830,7 @@ def estimate_completion():
                     stats.f_bsize * stats.f_bfree, stats.f_ffree)
     # truncate and close files
     for f in files:
-        f.truncate(0)
+        truncate_f(f)
 
         while True:
             try:

tests/TestFileUtilities.py

@@ -384,6 +384,48 @@ def win_symlink(src, linkname):
         delete(path, shred)
         self.assert_(not os.path.exists(path))
 
+    @unittest.skipIf('nt' != os.name, 'skipping on non-Windows')
+    def test_delete_locked(self):
+        """Unit test for delete() with locked file"""
+        # set up
+        def test_delete_locked_setup():
+            (fd, filename) = tempfile.mkstemp(prefix='bleachbit-test-worker')
+            os.write(fd, '123')
+            os.close(fd)
+            self.assertExists(filename)
+            self.assertEqual(3, getsize(filename))
+            return filename
+
+        # File is open but not opened exclusive, so expect that the
+        # file is truncated but not deleted.
+        # O_EXCL = fail if file exists (i.e., not an exclusive lock)
+        filename = test_delete_locked_setup()
+        f = os.open(filename, os.O_WRONLY | os.O_EXCL)
+        self.assertExists(filename)
+        self.assertEqual(3, getsize(filename))
+        with self.assertRaises(WindowsError):
+            delete(filename)
+        os.close(f)
+        self.assertExists(filename)
+        self.assertEqual(0, getsize(filename))
+        delete(filename)
+        self.assertNotExists(filename)
+
+        # File is open with exclusive lock, so expect the file is neither
+        # deleted nor truncated.
+        filename = test_delete_locked_setup()
+        from subprocess import call
+        call('start notepad.exe>>{}'.format(filename), shell=True)
+        self.assertExists(filename)
+        self.assertEqual(3, getsize(filename))
+        with self.assertRaises(WindowsError):
+            delete(filename)
+        call('taskkill /f /im notepad.exe')
+        self.assertExists(filename)
+        self.assertEqual(3, getsize(filename))
+        delete(filename)
+        self.assertNotExists(filename)
+
     @unittest.skipIf('nt' == os.name, 'skipping on Windows')
     def test_ego_owner(self):
         """Unit test for ego_owner()"""

tests/TestWorker.py

@@ -147,10 +147,14 @@ def __init__(self, action_element):
         self.pathname = action_element.getAttribute('path')
 
     def get_commands(self):
-        # Lock the file on Windows.  It should be marked for deletion.
-        f = os.open(self.pathname, os.O_RDWR | os.O_EXCL)
+        # Open the file with a non-exclusive lock, so the file should
+        # be truncated and marked for deletion. This is checked just on
+        # on Windows.
+        f = os.open(self.pathname, os.O_RDWR)
         yield Command.Delete(self.pathname)
         assert(os.path.exists(self.pathname))
+        from bleachbit.FileUtilities import getsize
+        assert(0==getsize(self.pathname))
         os.close(f)
 
         # real file, should succeed