New code for Windows drop-upload support. refs #1431

Signed-off-by: Daira Hopwood <daira@jacaranda.org>

src/allmydata/windows/inotify.py

@@ -0,0 +1,274 @@
+
+# Windows near-equivalent to twisted.internet.inotify
+# This should only be imported on Windows.
+
+import os, sys
+
+from twisted.internet import reactor
+from twisted.internet.threads import deferToThread
+
+from allmydata.util.fake_inotify import humanReadableMask, \
+    IN_WATCH_MASK, IN_ACCESS, IN_MODIFY, IN_ATTRIB, IN_CLOSE_NOWRITE, IN_CLOSE_WRITE, \
+    IN_OPEN, IN_MOVED_FROM, IN_MOVED_TO, IN_CREATE, IN_DELETE, IN_DELETE_SELF, \
+    IN_MOVE_SELF, IN_UNMOUNT, IN_Q_OVERFLOW, IN_IGNORED, IN_ONLYDIR, IN_DONT_FOLLOW, \
+    IN_MASK_ADD, IN_ISDIR, IN_ONESHOT, IN_CLOSE, IN_MOVED, IN_CHANGED
+[humanReadableMask, \
+    IN_WATCH_MASK, IN_ACCESS, IN_MODIFY, IN_ATTRIB, IN_CLOSE_NOWRITE, IN_CLOSE_WRITE, \
+    IN_OPEN, IN_MOVED_FROM, IN_MOVED_TO, IN_CREATE, IN_DELETE, IN_DELETE_SELF, \
+    IN_MOVE_SELF, IN_UNMOUNT, IN_Q_OVERFLOW, IN_IGNORED, IN_ONLYDIR, IN_DONT_FOLLOW, \
+    IN_MASK_ADD, IN_ISDIR, IN_ONESHOT, IN_CLOSE, IN_MOVED, IN_CHANGED]
+
+from allmydata.util.assertutil import _assert, precondition
+from allmydata.util.encodingutil import quote_output
+from allmydata.util import log, fileutil
+from allmydata.util.pollmixin import PollMixin
+
+from ctypes import WINFUNCTYPE, WinError, windll, POINTER, byref, create_string_buffer, addressof
+from ctypes.wintypes import BOOL, HANDLE, DWORD, LPCWSTR, LPVOID
+
+# <http://msdn.microsoft.com/en-us/library/gg258116%28v=vs.85%29.aspx>
+FILE_LIST_DIRECTORY              = 1
+
+# <http://msdn.microsoft.com/en-us/library/aa363858%28v=vs.85%29.aspx>
+CreateFileW = WINFUNCTYPE(HANDLE, LPCWSTR, DWORD, DWORD, LPVOID, DWORD, DWORD, HANDLE) \
+                  (("CreateFileW", windll.kernel32))
+
+FILE_SHARE_READ                  = 0x00000001
+FILE_SHARE_WRITE                 = 0x00000002
+FILE_SHARE_DELETE                = 0x00000004
+
+OPEN_EXISTING                    = 3
+
+FILE_FLAG_BACKUP_SEMANTICS       = 0x02000000
+
+# <http://msdn.microsoft.com/en-us/library/ms724211%28v=vs.85%29.aspx>
+CloseHandle = WINFUNCTYPE(BOOL, HANDLE)(("CloseHandle", windll.kernel32))
+
+# <http://msdn.microsoft.com/en-us/library/aa365465%28v=vs.85%29.aspx>
+ReadDirectoryChangesW = WINFUNCTYPE(BOOL, HANDLE, LPVOID, DWORD, BOOL, DWORD, POINTER(DWORD), LPVOID, LPVOID) \
+                            (("ReadDirectoryChangesW", windll.kernel32))
+
+FILE_NOTIFY_CHANGE_FILE_NAME     = 0x00000001
+FILE_NOTIFY_CHANGE_DIR_NAME      = 0x00000002
+FILE_NOTIFY_CHANGE_ATTRIBUTES    = 0x00000004
+#FILE_NOTIFY_CHANGE_SIZE         = 0x00000008
+FILE_NOTIFY_CHANGE_LAST_WRITE    = 0x00000010
+FILE_NOTIFY_CHANGE_LAST_ACCESS   = 0x00000020
+#FILE_NOTIFY_CHANGE_CREATION     = 0x00000040
+FILE_NOTIFY_CHANGE_SECURITY      = 0x00000100
+
+# <http://msdn.microsoft.com/en-us/library/aa364391%28v=vs.85%29.aspx>
+FILE_ACTION_ADDED                = 0x00000001
+FILE_ACTION_REMOVED              = 0x00000002
+FILE_ACTION_MODIFIED             = 0x00000003
+FILE_ACTION_RENAMED_OLD_NAME     = 0x00000004
+FILE_ACTION_RENAMED_NEW_NAME     = 0x00000005
+
+_action_to_string = {
+    FILE_ACTION_ADDED            : "FILE_ACTION_ADDED",
+    FILE_ACTION_REMOVED          : "FILE_ACTION_REMOVED",
+    FILE_ACTION_MODIFIED         : "FILE_ACTION_MODIFIED",
+    FILE_ACTION_RENAMED_OLD_NAME : "FILE_ACTION_RENAMED_OLD_NAME",
+    FILE_ACTION_RENAMED_NEW_NAME : "FILE_ACTION_RENAMED_NEW_NAME",
+}
+
+_action_to_inotify_mask = {
+    FILE_ACTION_ADDED            : IN_CREATE,
+    FILE_ACTION_REMOVED          : IN_DELETE,
+    FILE_ACTION_MODIFIED         : IN_CHANGED,
+    FILE_ACTION_RENAMED_OLD_NAME : IN_MOVED_FROM,
+    FILE_ACTION_RENAMED_NEW_NAME : IN_MOVED_TO,
+}
+
+INVALID_HANDLE_VALUE             = 0xFFFFFFFF
+
+
+class Event(object):
+    """
+    * action:   a FILE_ACTION_* constant (not a bit mask)
+    * filename: a Unicode string, giving the name relative to the watched directory
+    """
+    def __init__(self, action, filename):
+        self.action = action
+        self.filename = filename
+
+    def __repr__(self):
+        return "Event(%r, %r)" % (_action_to_string.get(self.action, self.action), self.filename)
+
+
+class FileNotifyInformation(object):
+    """
+    I represent a buffer containing FILE_NOTIFY_INFORMATION structures, and can
+    iterate over those structures, decoding them into Event objects.
+    """
+
+    def __init__(self, size=1024):
+        self.size = size
+        self.buffer = create_string_buffer(size)
+        address = addressof(self.buffer)
+        _assert(address & 3 == 0, "address 0x%X returned by create_string_buffer is not DWORD-aligned" % (address,))
+        self.data = None
+
+    def read_changes(self, hDirectory, recursive, filter):
+        bytes_returned = DWORD(0)
+        r = ReadDirectoryChangesW(hDirectory,
+                                  self.buffer,
+                                  self.size,
+                                  recursive,
+                                  filter,
+                                  byref(bytes_returned),
+                                  None,  # NULL -> no overlapped I/O
+                                  None   # NULL -> no completion routine
+                                 )
+        if r == 0:
+            raise WinError()
+        self.data = self.buffer.raw[:bytes_returned.value]
+
+    def __iter__(self):
+        # Iterator implemented as generator: <http://docs.python.org/library/stdtypes.html#generator-types>
+        pos = 0
+        while True:
+            bytes = self._read_dword(pos+8)
+            s = Event(self._read_dword(pos+4),
+                      self.data[pos+12 : pos+12+bytes].decode('utf-16-le'))
+
+            next_entry_offset = self._read_dword(pos)
+            yield s
+            if next_entry_offset == 0:
+                break
+            pos = pos + next_entry_offset
+
+    def _read_dword(self, i):
+        # little-endian
+        return ( ord(self.data[i])          |
+                (ord(self.data[i+1]) <<  8) |
+                (ord(self.data[i+2]) << 16) |
+                (ord(self.data[i+3]) << 24))
+
+
+def _open_directory(path_u):
+    hDirectory = CreateFileW(path_u,
+                             FILE_LIST_DIRECTORY,         # access rights
+                             FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
+                                                          # don't prevent other processes from accessing
+                             None,                        # no security descriptor
+                             OPEN_EXISTING,               # directory must already exist
+                             FILE_FLAG_BACKUP_SEMANTICS,  # necessary to open a directory
+                             None                         # no template file
+                            )
+    if hDirectory == INVALID_HANDLE_VALUE:
+        e = WinError()
+        raise OSError("Opening directory %s gave Windows error %r: %s" % (quote_output(path_u), e.args[0], e.args[1]))
+    return hDirectory
+
+
+def simple_test():
+    path_u = u"test"
+    filter = FILE_NOTIFY_CHANGE_FILE_NAME | FILE_NOTIFY_CHANGE_DIR_NAME | FILE_NOTIFY_CHANGE_LAST_WRITE
+    recursive = False
+
+    hDirectory = _open_directory(path_u)
+    fni = FileNotifyInformation()
+    print "Waiting..."
+    while True:
+        fni.read_changes(hDirectory, recursive, filter)
+        print repr(fni.data)
+        for info in fni:
+            print info
+
+
+NOT_STARTED = "NOT_STARTED"
+STARTED     = "STARTED"
+STOPPING    = "STOPPING"
+STOPPED     = "STOPPED"
+
+class INotify(PollMixin):
+    def __init__(self):
+        self._state = NOT_STARTED
+        self._filter = None
+        self._callbacks = None
+        self._hDirectory = None
+        self._path = None
+        self._pending = set()
+        self._pending_delay = 1.0
+
+    def set_pending_delay(self, delay):
+        self._pending_delay = delay
+
+    def startReading(self):
+        deferToThread(self._thread)
+        return self.poll(lambda: self._state != NOT_STARTED)
+
+    def stopReading(self):
+        # FIXME race conditions
+        if self._state != STOPPED:
+            self._state = STOPPING
+
+    def wait_until_stopped(self):
+        fileutil.write(os.path.join(self._path.path, u".ignore-me"), "")
+        return self.poll(lambda: self._state == STOPPED)
+
+    def watch(self, path, mask=IN_WATCH_MASK, autoAdd=False, callbacks=None, recursive=False):
+        precondition(self._state == NOT_STARTED, "watch() can only be called before startReading()", state=self._state)
+        precondition(self._filter is None, "only one watch is supported")
+        precondition(isinstance(autoAdd, bool), autoAdd=autoAdd)
+        precondition(isinstance(recursive, bool), recursive=recursive)
+        precondition(autoAdd == recursive, "need autoAdd and recursive to be the same", autoAdd=autoAdd, recursive=recursive)
+
+        self._path = path
+        path_u = path.path
+        if not isinstance(path_u, unicode):
+            path_u = path_u.decode(sys.getfilesystemencoding())
+            _assert(isinstance(path_u, unicode), path_u=path_u)
+
+        self._filter = FILE_NOTIFY_CHANGE_FILE_NAME | FILE_NOTIFY_CHANGE_DIR_NAME | FILE_NOTIFY_CHANGE_LAST_WRITE
+
+        if mask & (IN_ACCESS | IN_CLOSE_NOWRITE | IN_OPEN):
+            self._filter = self._filter | FILE_NOTIFY_CHANGE_LAST_ACCESS
+        if mask & IN_ATTRIB:
+            self._filter = self._filter | FILE_NOTIFY_CHANGE_ATTRIBUTES | FILE_NOTIFY_CHANGE_SECURITY
+
+        self._recursive = recursive
+        self._callbacks = callbacks or []
+        self._hDirectory = _open_directory(path_u)
+
+    def _thread(self):
+        try:
+            _assert(self._filter is not None, "no watch set")
+
+            # To call Twisted or Tahoe APIs, use reactor.callFromThread as described in
+            # <http://twistedmatrix.com/documents/current/core/howto/threading.html>.
+
+            fni = FileNotifyInformation()
+
+            while True:
+                self._state = STARTED
+                fni.read_changes(self._hDirectory, self._recursive, self._filter)
+                for info in fni:
+                    if self._state == STOPPING:
+                        hDirectory = self._hDirectory
+                        self._callbacks = None
+                        self._hDirectory = None
+                        CloseHandle(hDirectory)
+                        self._state = STOPPED
+                        return
+
+                    path = self._path.preauthChild(info.filename)  # FilePath with Unicode path
+                    #mask = _action_to_inotify_mask.get(info.action, IN_CHANGED)
+
+                    def _maybe_notify(path):
+                        if path not in self._pending:
+                            self._pending.add(path)
+                            def _do_callbacks():
+                                self._pending.remove(path)
+                                for cb in self._callbacks:
+                                    try:
+                                        cb(None, path, IN_CHANGED)
+                                    except Exception, e:
+                                        log.err(e)
+                            reactor.callLater(self._pending_delay, _do_callbacks)
+                    reactor.callFromThread(_maybe_notify, path)
+        except Exception, e:
+            log.err(e)
+            self._state = STOPPED
+            raise