1 /*
2  * Copyright (C) 2016 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #ifndef ART_RUNTIME_PLUGIN_H_
18 #define ART_RUNTIME_PLUGIN_H_
19 
20 #include <string>
21 #include "base/logging.h"
22 
23 namespace art {
24 
25 // This function is loaded from the plugin (if present) and called during runtime initialization.
26 // By the time this has been called the runtime has been fully initialized but not other native
27 // libraries have been loaded yet. Failure to initialize is considered a fatal error.
28 // TODO might want to give initialization function some arguments
29 using PluginInitializationFunction = bool (*)();
30 using PluginDeinitializationFunction = bool (*)();
31 
32 // A class encapsulating a plugin. There is no stable plugin ABI or API and likely never will be.
33 // TODO Might want to put some locking in this but ATM we only load these at initialization in a
34 // single-threaded fashion so not much need
35 class Plugin {
36  public:
Create(const std::string & lib)37   static Plugin Create(const std::string& lib) {
38     return Plugin(lib);
39   }
40 
IsLoaded()41   bool IsLoaded() const {
42     return dlopen_handle_ != nullptr;
43   }
44 
GetLibrary()45   const std::string& GetLibrary() const {
46     return library_;
47   }
48 
49   bool Load(/*out*/std::string* error_msg);
50   bool Unload();
51 
52 
~Plugin()53   ~Plugin() {
54     if (IsLoaded() && !Unload()) {
55       LOG(ERROR) << "Error unloading " << this;
56     }
57   }
58 
59   Plugin(const Plugin& other);
60 
61   // Create move constructor for putting this in a list
Plugin(Plugin && other)62   Plugin(Plugin&& other)
63       : library_(other.library_),
64         dlopen_handle_(other.dlopen_handle_) {
65     other.dlopen_handle_ = nullptr;
66   }
67 
68  private:
Plugin(const std::string & library)69   explicit Plugin(const std::string& library) : library_(library), dlopen_handle_(nullptr) { }
70 
71   std::string library_;
72   void* dlopen_handle_;
73 
74   friend std::ostream& operator<<(std::ostream &os, Plugin const& m);
75 };
76 
77 std::ostream& operator<<(std::ostream &os, Plugin const& m);
78 std::ostream& operator<<(std::ostream &os, const Plugin* m);
79 
80 }  // namespace art
81 
82 #endif  // ART_RUNTIME_PLUGIN_H_
83