Add RegistryMonitor

setup.py

@@ -2,7 +2,7 @@ from setuptools import setup, find_packages
 
 setup(
     name="galaxy.plugin.api",
-    version="0.50",
+    version="0.51",
     description="GOG Galaxy Integrations Python API",
     author='Galaxy team',
     author_email='galaxy@gog.com',

src/galaxy/registry_monitor.py

@@ -0,0 +1,98 @@
+import platform
+if platform.system().lower() == "windows":
+    import logging
+    import ctypes
+    from ctypes.wintypes import LONG, HKEY, LPCWSTR, DWORD, BOOL, HANDLE, LPVOID
+
+    LPSECURITY_ATTRIBUTES = LPVOID
+
+    RegOpenKeyEx = ctypes.windll.advapi32.RegOpenKeyExW
+    RegOpenKeyEx.restype = LONG
+    RegOpenKeyEx.argtypes = [HKEY, LPCWSTR, DWORD, DWORD, ctypes.POINTER(HKEY)]
+
+    RegCloseKey = ctypes.windll.advapi32.RegCloseKey
+    RegCloseKey.restype = LONG
+    RegCloseKey.argtypes = [HKEY]
+
+    RegNotifyChangeKeyValue = ctypes.windll.advapi32.RegNotifyChangeKeyValue
+    RegNotifyChangeKeyValue.restype = LONG
+    RegNotifyChangeKeyValue.argtypes = [HKEY, BOOL, DWORD, HANDLE, BOOL]
+
+    CloseHandle = ctypes.windll.kernel32.CloseHandle
+    CloseHandle.restype = BOOL
+    CloseHandle.argtypes = [HANDLE]
+
+    CreateEvent = ctypes.windll.kernel32.CreateEventW
+    CreateEvent.restype = BOOL
+    CreateEvent.argtypes = [LPSECURITY_ATTRIBUTES, BOOL, BOOL, LPCWSTR]
+
+    WaitForSingleObject = ctypes.windll.kernel32.WaitForSingleObject
+    WaitForSingleObject.restype = DWORD
+    WaitForSingleObject.argtypes = [HANDLE, DWORD]
+
+    ERROR_SUCCESS = 0x00000000
+
+    KEY_READ = 0x00020019
+    KEY_QUERY_VALUE = 0x00000001
+
+    REG_NOTIFY_CHANGE_NAME = 0x00000001
+    REG_NOTIFY_CHANGE_LAST_SET = 0x00000004
+
+    WAIT_OBJECT_0 = 0x00000000
+    WAIT_TIMEOUT = 0x00000102
+
+class RegistryMonitor:
+
+    def __init__(self, root, subkey):
+        self._root = root
+        self._subkey = subkey
+        self._event = CreateEvent(None, False, False, None)
+
+        self._key = None
+        self._open_key()
+        if self._key:
+            self._set_key_update_notification()
+
+    def close(self):
+        CloseHandle(self._event)
+        if self._key:
+            RegCloseKey(self._key)
+            self._key = None
+
+    def is_updated(self):
+        wait_result = WaitForSingleObject(self._event, 0)
+
+        # previously watched
+        if wait_result == WAIT_OBJECT_0:
+            self._set_key_update_notification()
+            return True
+
+        # no changes or no key before
+        if wait_result != WAIT_TIMEOUT:
+            # unexpected error
+            logging.warning("Unexpected WaitForSingleObject result %s", wait_result)
+            return False
+
+        if self._key is None:
+            self._open_key()
+
+        if self._key is None:
+            return False
+
+        self._set_key_update_notification()
+        return True
+
+    def _set_key_update_notification(self):
+        filter_ = REG_NOTIFY_CHANGE_NAME | REG_NOTIFY_CHANGE_LAST_SET
+        status = RegNotifyChangeKeyValue(self._key, True, filter_, self._event, True)
+        if status != ERROR_SUCCESS:
+            # key was deleted
+            RegCloseKey(self._key)
+            self._key = None
+
+    def _open_key(self):
+        access = KEY_QUERY_VALUE | KEY_READ
+        self._key = HKEY()
+        rc = RegOpenKeyEx(self._root, self._subkey, 0, access, ctypes.byref(self._key))
+        if rc != ERROR_SUCCESS:
+            self._key = None