Move to kernel style SPDX license identifiers

[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 9d692f2d32b03579f2dc6cda3ed330fb9050c792..21fb2d666b6efd04e2704cc494d8493dc2aef4a9 100644 (file)
--- a/src/bindings/python/bt2/bt2/py_plugin.py
+++ b/src/bindings/python/bt2/bt2/py_plugin.py
@@ -1,27 +1,14 @@
-# The MIT License (MIT)
+# SPDX-License-Identifier: MIT
 #
 # Copyright (c) 2017 Philippe Proulx <pproulx@efficios.com>
-#
-# Permission is hereby granted, free of charge, to any person obtaining a copy
-# of this software and associated documentation files (the "Software"), to deal
-# in the Software without restriction, including without limitation the rights
-# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-# copies of the Software, and to permit persons to whom the Software is
-# furnished to do so, subject to the following conditions:
-#
-# The above copyright notice and this permission notice shall be included in
-# all copies or substantial portions of the Software.
-#
-# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-# THE SOFTWARE.
 
 from bt2 import utils
 from bt2 import component as bt2_component
+import sys
+
+
+# Python plugin path to `_PluginInfo` (cache)
+_plugin_infos = {}
 
 
 def plugin_component_class(component_class):
@@ -35,8 +22,6 @@ def plugin_component_class(component_class):
 def register_plugin(
     module_name, name, description=None, author=None, license=None, version=None
 ):
-    import sys
-
     if module_name not in sys.modules:
         raise RuntimeError(
             "cannot find module '{}' in loaded modules".format(module_name)
@@ -102,6 +87,10 @@ 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
@@ -115,7 +104,7 @@ 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()
 
@@ -137,4 +126,5 @@ 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