filter hooks by connection and context in core

plugins/python/_zoitechat_filters.py

@@ -0,0 +1,36 @@
+"""Context restrictions evaluated by core before entering Python."""
+import operator
+import _zoitechat as api
+from _zoitechat_embedded import ffi, lib
+
+__all__ = ['hook_server_filtered', 'hook_print_filtered']
+
+
+def _register(name, callback, userdata, priority, connection_id, channel, server):
+    if not callable(callback):
+        raise TypeError('callback must be callable')
+    connection_id = -1 if connection_id is None else operator.index(connection_id)
+    if connection_id < -1 or connection_id > 2147483647:
+        raise ValueError('connection_id must fit the C API; -1 means any')
+    plugin = api.__get_current_plugin()
+    hook = plugin.add_hook(callback, userdata)
+    register = lib.zoitechat_hook_server_filtered if server else lib.zoitechat_hook_print_filtered
+    dispatch = lib._on_server_attrs_hook if server else lib._on_print_attrs_hook
+    handle = register(lib.ph, name.encode(), priority, 0, connection_id,
+                      ffi.NULL if channel is None else channel.encode(), dispatch, hook.handle)
+    if handle == ffi.NULL:
+        hook.is_unload = True
+        plugin.remove_hook(id(hook))
+        raise RuntimeError('unable to install filtered hook')
+    hook.zoitechat_hook = handle
+    return id(hook)
+
+
+def hook_server_filtered(name, callback, userdata=None, priority=api.PRI_NORM,
+                         connection_id=None, channel=None):
+    return _register(name, callback, userdata, priority, connection_id, channel, True)
+
+
+def hook_print_filtered(name, callback, userdata=None, priority=api.PRI_NORM,
+                        connection_id=None, channel=None):
+    return _register(name, callback, userdata, priority, connection_id, channel, False)