configure: enable -Wsuggest-attribute=format

[babeltrace.git] / src / bindings / python / bt2 / bt2 / py_plugin.py

diff --git a/src/bindings/python/bt2/bt2/py_plugin.py b/src/bindings/python/bt2/bt2/py_plugin.py
index b845030863ce224582406af5698e840a3d70465c..f1142766e3230152ef08acf458ba3069b58ebac7 100644 (file)
--- a/src/bindings/python/bt2/bt2/py_plugin.py
+++ b/src/bindings/python/bt2/bt2/py_plugin.py
@@ -21,23 +21,29 @@
 # THE SOFTWARE.
 
 from bt2 import utils
-import bt2.component
+from bt2 import component as bt2_component
+import sys
+
+
+# Python plugin path to `_PluginInfo` (cache)
+_plugin_infos = {}
 
 
 def plugin_component_class(component_class):
-    if not issubclass(component_class, bt2.component._UserComponent):
+    if not issubclass(component_class, bt2_component._UserComponent):
         raise TypeError('component class is not a subclass of a user component class')
 
     component_class._bt_plugin_component_class = None
     return component_class
 
 
-def register_plugin(module_name, name, description=None, author=None,
-                    license=None, version=None):
-    import sys
-
+def register_plugin(
+    module_name, name, description=None, author=None, license=None, version=None
+):
     if module_name not in sys.modules:
-        raise RuntimeError("cannot find module '{}' in loaded modules".format(module_name))
+        raise RuntimeError(
+            "cannot find module '{}' in loaded modules".format(module_name)
+        )
 
     utils._check_str(name)
 
@@ -52,11 +58,13 @@ def register_plugin(module_name, name, description=None, author=None,
 
     if version is not None:
         if not _validate_version(version):
-            raise ValueError('wrong version: expecting a tuple: (major, minor, patch) or (major, minor, patch, extra)')
+            raise ValueError(
+                'wrong version: expecting a tuple: (major, minor, patch) or (major, minor, patch, extra)'
+            )
 
-    sys.modules[module_name]._bt_plugin_info = _PluginInfo(name, description,
-                                                           author, license,
-                                                           version)
+    sys.modules[module_name]._bt_plugin_info = _PluginInfo(
+        name, description, author, license, version
+    )
 
 
 def _validate_version(version):
@@ -97,6 +105,10 @@ class _PluginInfo:
 
 # called by the BT plugin system
 def _try_load_plugin_module(path):
+    if path in _plugin_infos:
+        # do not load module and create plugin info twice for this path
+        return _plugin_infos[path]
+
     import importlib.machinery
     import inspect
     import hashlib
@@ -110,7 +122,7 @@ def _try_load_plugin_module(path):
     h = hashlib.sha256()
     h.update(path.encode())
     module_name = 'bt_plugin_{}'.format(h.hexdigest())
-
+    assert module_name not in sys.modules
     # try loading the module: any raised exception is catched by the caller
     mod = importlib.machinery.SourceFileLoader(module_name, path).load_module()
 
@@ -132,4 +144,5 @@ def _try_load_plugin_module(path):
 
     comp_class_entries = inspect.getmembers(mod, is_user_comp_class)
     plugin_info.comp_class_addrs = [entry[1].addr for entry in comp_class_entries]
+    _plugin_infos[path] = plugin_info
     return plugin_info