X-Git-Url: http://git.efficios.com/?a=blobdiff_plain;f=src%2Fbindings%2Fpython%2Fbt2%2Fbt2%2Fpy_plugin.py;h=6f067e8b4d59c4e794362372a05ccf8f008393ec;hb=f5567ea88d172767b34373bc6e402da8bfd85ef8;hp=9d692f2d32b03579f2dc6cda3ed330fb9050c792;hpb=3fb99a226ccb40c79de6b55b5a249d93b9c5262e;p=babeltrace.git

diff --git a/src/bindings/python/bt2/bt2/py_plugin.py b/src/bindings/python/bt2/bt2/py_plugin.py
index 9d692f2d..6f067e8b 100644
--- a/src/bindings/python/bt2/bt2/py_plugin.py
+++ b/src/bindings/python/bt2/bt2/py_plugin.py
@@ -1,32 +1,19 @@
-# 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):
     if not issubclass(component_class, bt2_component._UserComponent):
-        raise TypeError('component class is not a subclass of a user component class')
+        raise TypeError("component class is not a subclass of a user component class")
 
     component_class._bt_plugin_component_class = None
     return 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)
@@ -56,7 +41,7 @@ def register_plugin(
     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)'
+                "wrong version: expecting a tuple: (major, minor, patch) or (major, minor, patch, extra)"
             )
 
     sys.modules[module_name]._bt_plugin_info = _PluginInfo(
@@ -102,25 +87,29 @@ 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
 
     if path is None:
-        raise TypeError('missing path')
+        raise TypeError("missing path")
 
     # In order to load the module uniquely from its path, even from
     # different files which have the same basename, we hash the path
     # and prefix with `bt_plugin_`. This is its key in sys.modules.
     h = hashlib.sha256()
     h.update(path.encode())
-    module_name = 'bt_plugin_{}'.format(h.hexdigest())
-
+    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()
 
     # we have the module: look for its plugin info first
-    if not hasattr(mod, '_bt_plugin_info'):
+    if not hasattr(mod, "_bt_plugin_info"):
         raise RuntimeError("missing '_bt_plugin_info' module attribute")
 
     plugin_info = mod._bt_plugin_info
@@ -130,11 +119,12 @@ def _try_load_plugin_module(path):
         if not inspect.isclass(obj):
             return False
 
-        if not hasattr(obj, '_bt_plugin_component_class'):
+        if not hasattr(obj, "_bt_plugin_component_class"):
             return False
 
         return True
 
     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