use named pipes for mpv on windows

currently using non-blocking mode which involves a sleep in the read
loop - overlapped i/o might be a better option in the future

anki/mpv.py

@@ -54,6 +54,9 @@ class MPVCommandError(MPVError):
 class MPVTimeoutError(MPVError):
     pass
 
+from anki.utils import isWin
+if isWin:
+    import win32file, win32pipe, pywintypes, winerror
 
 class MPVBase:
     """Base class for communication with the mpv media player via unix socket
@@ -64,7 +67,9 @@ class MPVBase:
 
     default_argv = [
         "--idle",
-        "--no-terminal"
+        "--no-terminal",
+        "--force-window=no",
+        "--ontop",
     ]
 
     def __init__(self, window_id=None, debug=False):
@@ -119,6 +124,9 @@ class MPVBase:
         """Create a random socket filename which we pass to mpv with the
            --input-unix-socket option.
         """
+        if isWin:
+            self._sock_filename = "ankimpv"
+            return
         fd, self._sock_filename = tempfile.mkstemp(prefix="mpv.")
         os.close(fd)
         os.remove(self._sock_filename)
@@ -132,6 +140,14 @@ class MPVBase:
             time.sleep(0.1)
 
             try:
+                if isWin:
+                    self._sock = win32file.CreateFile(r'\\.\pipe\ankimpv',
+                                                       win32file.GENERIC_READ | win32file.GENERIC_WRITE,
+                                                       0, None, win32file.OPEN_EXISTING, 0, None)
+                    win32pipe.SetNamedPipeHandleState(self._sock,
+                                                      1, # PIPE_NOWAIT
+                                                      None, None)
+                else:
                     self._sock = socket.socket(socket.AF_UNIX)
                     self._sock.connect(self._sock_filename)
             except (FileNotFoundError, ConnectionRefusedError):
@@ -179,6 +195,19 @@ class MPVBase:
         """
         buf = b""
         while not self._stop_event.is_set():
+            if isWin:
+                try:
+                    (n, b) = win32file.ReadFile(self._sock, 4096)
+                    buf += b
+                except pywintypes.error as err:
+                    if err.args[0] == winerror.ERROR_NO_DATA:
+                        time.sleep(0.1)
+                        continue
+                    elif err.args[0] == winerror.ERROR_BROKEN_PIPE:
+                        return
+                    else:
+                        raise
+            else:
                 r, w, e = select.select([self._sock], [], [], 1)
                 if r:
                     b = self._sock.recv(1024)
@@ -264,6 +293,9 @@ class MPVBase:
             raise MPVTimeoutError("unable to put request")
 
         # Write the message data to the socket.
+        if isWin:
+            win32file.WriteFile(self._sock, data)
+        else:
             while data:
                 size = self._sock.send(data)
                 if size == 0: