Static plugin loading using symbol module resolution (#21)

* Static plugin loading using symbol moodule resolution

* Avoid exceptions in isSymbolAvailable

* Removed deprecated functions; revised loadLibrary function

* Add method to plugin loader to load valid libraries in the correct order; revised implementation of plugin loader functions to use library loader function

* Updated function signature of getAllAvailableSymbols

* Return libraries specified by absolute paths at the front of the return list

* Update createSharedInstance signature to match other function

* Fix macro formatting

* Add unit test which uses full path for library name

* Add plugin achor unit test

* Update decorate to support library name as full path

* Add name to clang format CI

---------

Co-authored-by: Michael Ripperger <michael.ripperger@swri.org>

Author: Levi-Armstrong

.clang-tidy

@@ -6,6 +6,7 @@ Checks: >
     clang-analyzer-*,
     -clang-analyzer-cplusplus*,
     bugprone-*,
+    -bugprone-easily-swappable-parameters,
     cppcoreguidelines-*,
     -cppcoreguidelines-macro-usage,
     -cppcoreguidelines-pro-type-static-cast-downcast,
@@ -16,6 +17,7 @@ Checks: >
     -cppcoreguidelines-pro-bounds-constant-array-index,
     -cppcoreguidelines-avoid-magic-numbers,
     -cppcoreguidelines-non-private-member-variables-in-classes,
+    -cppcoreguidelines-avoid-non-const-global-variables,
     misc-*,
     -misc-non-private-member-variables-in-classes,
     -misc-no-recursion,
@@ -28,6 +30,7 @@ Checks: >
     -readability-named-parameter,
     -readability-magic-numbers,
     -readability-isolate-declaration,
+    -readability-identifier-length,
     -readability-function-cognitive-complexity
 WarningsAsErrors: >
     -*,
@@ -36,6 +39,7 @@ WarningsAsErrors: >
     clang-analyzer-*,
     -clang-analyzer-cplusplus*,
     bugprone-*,
+    -bugprone-easily-swappable-parameters,
     cppcoreguidelines-*,
     -cppcoreguidelines-macro-usage,
     -cppcoreguidelines-pro-type-static-cast-downcast,
@@ -46,6 +50,7 @@ WarningsAsErrors: >
     -cppcoreguidelines-pro-bounds-constant-array-index,
     -cppcoreguidelines-avoid-magic-numbers,
     -cppcoreguidelines-non-private-member-variables-in-classes,
+    -cppcoreguidelines-avoid-non-const-global-variables,
     misc-*,
     -misc-non-private-member-variables-in-classes,
     -misc-no-recursion,
@@ -58,6 +63,7 @@ WarningsAsErrors: >
     -readability-named-parameter,
     -readability-magic-numbers,
     -readability-isolate-declaration,
+    -readability-identifier-length,
     -readability-function-cognitive-complexity
 HeaderFilterRegex: '.*'
 AnalyzeTemporaryDtors: false
@@ -69,4 +75,6 @@ CheckOptions:
     value:           '1'
   - key:             cppcoreguidelines-special-member-functions.AllowSoleDefaultDtor
     value:           '1'
+ExtraArgs:
+  - '-std=c++17'
 ...

.github/workflows/clang_format.yml

@@ -10,14 +10,15 @@ on:
 
 jobs:
   clang_format:
-    runs-on: ubuntu-latest
+    name: Clang-Format
+    runs-on: ubuntu-22.04
     steps:
       - uses: actions/checkout@v4
 
       - name: Run clang format
         run: |
           sudo apt update
-          sudo apt install -y git clang-format
+          sudo apt install -y git clang-format-14
           if [ $? -ge 1 ]; then return 1; fi
           ./.run-clang-format
           if [ $? -ge 1 ]; then return 1; fi

.github/workflows/ubuntu.yml

@@ -33,7 +33,7 @@ jobs:
           path: target_ws/src
 
       - name: Build and Tests
-        uses: tesseract-robotics/colcon-action@v9
+        uses: tesseract-robotics/colcon-action@v11
         with:
           before-script: 'apt install -y -qq clang-tidy lcov'
           ccache-prefix: ${{ matrix.distro }}

.run-clang-format

@@ -1,2 +1,2 @@
 #!/bin/bash
-find . -type f -regex '.*\.\(cpp\|hpp\|cc\|cxx\|h\|hxx\)' -exec clang-format-8 -style=file -i {} \;
+find . -type f -regex '.*\.\(cpp\|hpp\|cc\|cxx\|h\|hxx\)' -exec clang-format-14 -style=file -i {} \;

examples/example.cpp

@@ -17,10 +17,16 @@
  * limitations under the License.
  */
 #include "plugin.h"
-#include <boost_plugin_loader/plugin_loader.h>
+
+// STD
+#include <string>
+#include <vector>
 #include <iostream>
 #include <cassert>
 
+// Boost Plugin Loader
+#include <boost_plugin_loader/plugin_loader.h>
+
 using boost_plugin_loader::PluginLoader;
 using boost_plugin_loader::Printer;
 using boost_plugin_loader::Shape;
@@ -31,24 +37,24 @@ int main(int /*argc*/, char** /*argv*/)  // NOLINT
   loader.search_paths.insert(PLUGIN_DIR);
   loader.search_libraries.insert(PLUGINS);
 
-  std::vector<std::string> printer_plugins = loader.getAvailablePlugins<Printer>();
+  const std::vector<std::string> printer_plugins = loader.getAvailablePlugins<Printer>();
   assert(printer_plugins.size() == 2);
 
   for (const std::string& plugin_name : printer_plugins)
   {
-    std::cout << "Loading plugin '" << plugin_name << "'" << std::endl;
-    Printer::Ptr plugin = loader.createInstance<Printer>(plugin_name);
+    std::cout << "Loading plugin '" << plugin_name << "'\n";
+    const Printer::Ptr plugin = loader.createInstance<Printer>(plugin_name);
     assert(plugin != nullptr);
     plugin->operator()();
   }
 
-  std::vector<std::string> shape_plugins = loader.getAvailablePlugins<Shape>();
+  const std::vector<std::string> shape_plugins = loader.getAvailablePlugins<Shape>();
   assert(shape_plugins.size() == 2);
 
   for (const std::string& plugin_name : shape_plugins)
   {
-    std::cout << "Loading plugin '" << plugin_name << "'" << std::endl;
-    Printer::Ptr plugin = loader.createInstance<Printer>(plugin_name);
+    std::cout << "Loading plugin '" << plugin_name << "'\n";
+    const Printer::Ptr plugin = loader.createInstance<Printer>(plugin_name);
     assert(plugin != nullptr);
     plugin->operator()();
   }

examples/plugin.cpp

@@ -17,7 +17,13 @@
  * limitations under the License.
  */
 #include "plugin.h"
-#include <boost_plugin_loader/plugin_loader.hpp>
+
+// STD
+#include <string>
+
+// Boost Plugin Loader
+#include <boost_plugin_loader/plugin_loader.h>
+#include <boost_plugin_loader/plugin_loader.hpp>  // NOLINT(misc-include-cleaner)
 
 namespace boost_plugin_loader
 {

examples/plugin.h

@@ -34,6 +34,7 @@ class Printer
 {
 public:
   using Ptr = std::shared_ptr<Printer>;
+  virtual ~Printer() = default;
   virtual void operator()() const = 0;
 
 private:
@@ -47,6 +48,7 @@ class Shape
 {
 public:
   using Ptr = std::shared_ptr<Shape>;
+  virtual ~Shape() = default;
   virtual void operator()() const = 0;
 
 private:

examples/plugin_impl.cpp

@@ -27,7 +27,7 @@ struct ConsolePrinter : public Printer
 public:
   void operator()() const override
   {
-    std::cout << "IMPL: ConsolePrinter" << std::endl;
+    std::cout << "IMPL: ConsolePrinter\n";
   }
 };
 
@@ -36,7 +36,7 @@ struct HelloWorldPrinter : public Printer
 public:
   void operator()() const override
   {
-    std::cout << "IMPL: Hello World" << std::endl;
+    std::cout << "IMPL: Hello World\n";
   }
 };
 
@@ -45,7 +45,7 @@ struct Square : public Shape
 public:
   void operator()() const override
   {
-    std::cout << "IMPL: Square" << std::endl;
+    std::cout << "IMPL: Square\n";
   }
 };
 
@@ -54,7 +54,7 @@ struct Triangle : public Shape
 public:
   void operator()() const override
   {
-    std::cout << "IMPL: Triangle" << std::endl;
+    std::cout << "IMPL: Triangle\n";
   }
 };
 

include/boost_plugin_loader/macros.h

@@ -26,4 +26,11 @@
   extern "C" BOOST_SYMBOL_EXPORT DERIVED_CLASS ALIAS;                                                                  \
   BOOST_DLL_SECTION(SECTION, read) BOOST_DLL_SELECTANY DERIVED_CLASS ALIAS;
 
+#define PLUGIN_ANCHOR_DECL(ANCHOR_NAME) const void* ANCHOR_NAME();  // NOLINT
+
+// clang-format off
+#define PLUGIN_ANCHOR_IMPL(ANCHOR_NAME)                                                                                \
+  const void* ANCHOR_NAME() { return (const void*)(&ANCHOR_NAME); } // NOLINT
+// clang-format on
+
 #endif  // BOOST_PLUGIN_LOADER_MACROS_H

include/boost_plugin_loader/plugin_loader.h

@@ -19,8 +19,8 @@
 #ifndef BOOST_PLUGIN_LOADER_PLUGIN_LOADER_H
 #define BOOST_PLUGIN_LOADER_PLUGIN_LOADER_H
 
+// STD
 #include <set>
-#include <unordered_map>
 #include <string>
 #include <memory>
 #include <vector>
@@ -107,8 +107,7 @@ class PluginLoader
    * class in order to find all implementations of that plugin interface in the libraries containing plugins.
    */
   template <class PluginBase>
-  typename std::enable_if<has_getSection<PluginBase>::value, std::vector<std::string>>::type
-  getAvailablePlugins() const;
+  typename std::enable_if_t<has_getSection<PluginBase>::value, std::vector<std::string>> getAvailablePlugins() const;
 
   /**
    * @brief Check if plugin is available
@@ -130,6 +129,20 @@ class PluginLoader
    */
   inline std::vector<std::string> getAvailableSections(bool include_hidden = false) const;
 
+  /**
+   * @brief Utility function to add library containing symbol to the search env variable
+   *
+   * In some cases the name and location of a library is unknown at runtime, but a symbol can
+   * be linked at compile time. This is true for Python auditwheel distributions. This
+   * utility function will determine the location of the library, and add it to the library search
+   * environment variable so it can be found.
+   *
+   * @param symbol_ptr Pointer to the symbol to find
+   * @param search_libraries_env The environmental variable to modify
+   */
+  static inline void addSymbolLibraryToSearchLibrariesEnv(const void* symbol_ptr,
+                                                          const std::string& search_libraries_env);
+
   /**
    * @brief The number of plugins stored. The size of plugins variable
    * @return The number of plugins.
@@ -149,12 +162,12 @@ class PluginLoader
                          const std::set<std::string>& search_libraries) const;
 
   template <typename PluginBase>
-  typename std::enable_if<!has_getSection<PluginBase>::value, void>::type
+  typename std::enable_if_t<!has_getSection<PluginBase>::value, void>
   reportError(std::ostream& msg, const std::string& plugin_name, bool search_system_folders,
               const std::set<std::string>& search_paths, const std::set<std::string>& search_libraries) const;
 
   template <typename PluginBase>
-  typename std::enable_if<has_getSection<PluginBase>::value, void>::type
+  typename std::enable_if_t<has_getSection<PluginBase>::value, void>
   reportError(std::ostream& msg, const std::string& plugin_name, bool search_system_folders,
               const std::set<std::string>& search_paths, const std::set<std::string>& search_libraries) const;
 };