1 //
2 // Copyright 2016 Pixar
3 //
4 // Licensed under the Apache License, Version 2.0 (the "Apache License")
5 // with the following modification; you may not use this file except in
6 // compliance with the Apache License and the following modification to it:
7 // Section 6. Trademarks. is deleted and replaced with:
8 //
9 // 6. Trademarks. This License does not grant permission to use the trade
10 //    names, trademarks, service marks, or product names of the Licensor
11 //    and its affiliates, except as required to comply with Section 4(c) of
12 //    the License and to reproduce the content of the NOTICE file.
13 //
14 // You may obtain a copy of the Apache License at
15 //
16 //     http://www.apache.org/licenses/LICENSE-2.0
17 //
18 // Unless required by applicable law or agreed to in writing, software
19 // distributed under the Apache License with the above modification is
20 // distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
21 // KIND, either express or implied. See the Apache License for the specific
22 // language governing permissions and limitations under the Apache License.
23 //
24 /// \file staticInterface.cpp
25 
26 #include "pxr/pxr.h"
27 #include "pxr/base/plug/staticInterface.h"
28 #include "pxr/base/plug/interfaceFactory.h"
29 #include "pxr/base/plug/plugin.h"
30 #include "pxr/base/plug/registry.h"
31 #include "pxr/base/tf/diagnostic.h"
32 #include "pxr/base/tf/scoped.h"
33 #include <mutex>
34 #include <string>
35 
36 PXR_NAMESPACE_OPEN_SCOPE
37 
38 static std::mutex _initializationMutex;
39 
40 void
_LoadAndInstantiate(const std::type_info & type) const41 Plug_StaticInterfaceBase::_LoadAndInstantiate(const std::type_info& type) const
42 {
43     // Double checked locking.
44     std::lock_guard<std::mutex> lock(_initializationMutex);
45     if (_initialized) {
46         // Someone beat us to the initialization.
47         return;
48     }
49 
50     // We attempt initialization only once so set _initialized when we return
51     // even if we fail to load or instantiate.  We must not set it before we
52     // return because other threads would be able to observe partial
53     // initialization.
54     TfScoped<> initializeOnReturn{[this]() { _initialized = true; }};
55 
56     // Validate type.
57     // We use FindByName because Find requres that std::type_info has been
58     // regisered, but that won't happen until the plugin is loaded.
59     const TfType &tfType =
60         TfType::FindByName(TfType::GetCanonicalTypeName(type));
61     if (!tfType) {
62         TF_CODING_ERROR("Failed to load plugin interface: "
63                         "Can't find type %s", type.name());
64         return;
65     }
66     if (tfType.IsRoot()) {
67         TF_CODING_ERROR("Failed to load plugin interface: "
68                         "Can't manufacture type %s",
69                         tfType.GetTypeName().c_str());
70         return;
71     }
72 
73     // Get the plugin with type.
74     PlugPluginPtr plugin = PlugRegistry::GetInstance().GetPluginForType(tfType);
75     if (!plugin) {
76         TF_RUNTIME_ERROR("Failed to load plugin interface: "
77                          "Can't find plugin that defines type %s",
78                          tfType.GetTypeName().c_str());
79         return;
80     }
81 
82     // Load the plugin.
83     if (!plugin->Load()) {
84         // Error already reported.
85         return;
86     }
87 
88     // Manufacture the type.
89     Plug_InterfaceFactory::Base* factory =
90         tfType.GetFactory<Plug_InterfaceFactory::Base>();
91     if (!factory) {
92         TF_CODING_ERROR("Failed to load plugin interface: "
93                         "No default constructor for type %s",
94                         tfType.GetTypeName().c_str());
95         return;
96     }
97     _ptr = factory->New();
98 
99     // Report on error.
100     if (!_ptr) {
101         TF_CODING_ERROR("Failed to load plugin interface: "
102                         "Plugin didn't manufacture an instance of %s",
103                         tfType.GetTypeName().c_str());
104     }
105 }
106 
107 PXR_NAMESPACE_CLOSE_SCOPE
108