Plugin.h

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#ifndef SimTK_SimTKCOMMON_PLUGIN_H_
#define SimTK_SimTKCOMMON_PLUGIN_H_

/* -------------------------------------------------------------------------- *
 *                       Simbody(tm): SimTKcommon                             *
 * -------------------------------------------------------------------------- *
 * This is part of the SimTK biosimulation toolkit originating from           *
 * Simbios, the NIH National Center for Physics-Based Simulation of           *
 * Biological Structures at Stanford, funded under the NIH Roadmap for        *
 * Medical Research, grant U54 GM072970. See https://simtk.org/home/simbody.  *
 *                                                                            *
 * Portions copyright (c) 2009-12 Stanford University and the Authors.        *
 * Authors: Michael Sherman                                                   *
 * Contributors:                                                              *
 *                                                                            *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may    *
 * not use this file except in compliance with the License. You may obtain a  *
 * copy of the License at http://www.apache.org/licenses/LICENSE-2.0.         *
 *                                                                            *
 * Unless required by applicable law or agreed to in writing, software        *
 * distributed under the License is distributed on an "AS IS" BASIS,          *
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.   *
 * See the License for the specific language governing permissions and        *
 * limitations under the License.                                             *
 * -------------------------------------------------------------------------- */

#include "SimTKcommon/internal/common.h"
#include "SimTKcommon/internal/Array.h"
#include "SimTKcommon/internal/Pathname.h"
#include <string>
#include <stdexcept>

namespace SimTK {

class SimTK_SimTKCOMMON_EXPORT Plugin {
public:
    explicit Plugin(const std::string& defaultPathname="");
    ~Plugin();  // unloads the plugin if it was loaded

    bool load(const std::string& name="");

    void unload();

    bool isLoaded()                   const {return m_handle != 0;}

    const std::string& getLoadedPathname() const {
        return m_loadedPathname; // empty if nothing loaded
    }

    std::string getLastErrorMessage() const {return m_lastMessage;}

    void setSearchPath(const Array_<std::string>& pathIn) {
        m_searchPath.clear();
        for (unsigned i=0; i < pathIn.size(); ++i) 
            addSearchDirectory(pathIn[i]);
    }

    const Array_<std::string>& getSearchPath() const {return m_searchPath;}

    void addSearchDirectory(const std::string& directory) {
        const std::string absDir = Pathname::getAbsoluteDirectoryPathname(directory);
        if (!absDir.empty())
            m_searchPath.push_back(absDir);
    }

    void prependSearchDirectory(const std::string& directory) {
        const std::string absDir = Pathname::getAbsoluteDirectoryPathname(directory);
        if (!absDir.empty())
            m_searchPath.insert(m_searchPath.begin(), absDir);
    }


    static void* loadPluginByFileName(const std::string& name, std::string& errMsg);
    static void* loadDebugOrReleasePlugin(const std::string& base, const std::string& extension,
                                          std::string& loadedFileName, std::string& errMsg);
    static void* getSymbolAddress(void* handle, const std::string& name, std::string& errMsg);
    static void unloadPlugin(void* handle);

    static bool deconstructLibraryName( const std::string& name,
                                        bool&        isAbsolutePath,
                                        std::string& directory,
                                        std::string& libPrefix,
                                        std::string& baseName,
                                        std::string& debugSuffix,
                                        std::string& extension);

    static std::string getDynamicLibPrefix();

    static std::string getDynamicLibExtension();

    static std::string getDynamicLibDebugSuffix();

protected:
    std::string                 m_defaultName; // if any
    Array_<std::string>         m_searchPath;

    std::string                 m_loadedPathname; // absolute
    void*                       m_handle;
    mutable std::string         m_lastMessage;

};


#define SimTK_PLUGIN_XXX_MAKE_HOLDER(FuncName)          \
    struct FuncName##__Holder__ {                       \
        FuncName##__Holder__() : fp(0) {}               \
        bool loadSym(void* h, std::string& msg) const { \
            if(!fp) fp =(FuncName##__Type__)            \
                Plugin::getSymbolAddress(h, #FuncName, msg);   \
            return (fp!=0);                             \
        }                                               \
        mutable FuncName##__Type__ fp;                  \
    } FuncName##__Ref__
#define SimTK_PLUGIN_XXX_MAKE_BODY(FuncName)            \
    if (!FuncName##__Ref__.loadSym(m_handle,m_lastMessage)) \
    throw std::runtime_error                            \
      ("Plugin function " #FuncName " not found: " + m_lastMessage); \
    return FuncName##__Ref__.fp
#define SimTK_PLUGIN_XXX_MAKE_SYMTEST(Symbol)           \
    bool has_##Symbol() const {                          \
        return Symbol##__Ref__.loadSym(m_handle,m_lastMessage);   \
    }

#define SimTK_PLUGIN_DEFINE_SYMBOL(Type, SymName)   \
    typedef Type SymName##__Type__;                 \
    SimTK_PLUGIN_XXX_MAKE_HOLDER(SymName);          \
    const Type& SymName() const {                   \
        if (!SymName##__Ref__.loadSym(m_handle,m_lastMessage))  \
        throw std::runtime_error                                \
          ("Plugin symbol " #SymName " not found: " + m_lastMessage); \
        return *(SymName##__Ref__.fp);              \
    }

#define SimTK_PLUGIN_DEFINE_FUNCTION(RetType, FuncName) \
    typedef RetType (*FuncName##__Type__)();            \
    SimTK_PLUGIN_XXX_MAKE_HOLDER(FuncName);             \
    RetType FuncName() const {                          \
        SimTK_PLUGIN_XXX_MAKE_BODY(FuncName)();         \
    }                                                   \
    SimTK_PLUGIN_XXX_MAKE_SYMTEST(FuncName)

#define SimTK_PLUGIN_DEFINE_FUNCTION1(RetType, FuncName, Arg1) \
    typedef RetType (*FuncName##__Type__)(Arg1);        \
    SimTK_PLUGIN_XXX_MAKE_HOLDER(FuncName);             \
    RetType FuncName(Arg1 a1) const {                   \
        SimTK_PLUGIN_XXX_MAKE_BODY(FuncName)(a1);       \
    }                                                   \
    SimTK_PLUGIN_XXX_MAKE_SYMTEST(FuncName)

#define SimTK_PLUGIN_DEFINE_FUNCTION2(RetType, FuncName, Arg1, Arg2) \
    typedef RetType (*FuncName##__Type__)(Arg1,Arg2);   \
    SimTK_PLUGIN_XXX_MAKE_HOLDER(FuncName);             \
    RetType FuncName(Arg1 a1, Arg2 a2) const {          \
        SimTK_PLUGIN_XXX_MAKE_BODY(FuncName)(a1,a2);    \
    }                                                   \
    SimTK_PLUGIN_XXX_MAKE_SYMTEST(FuncName)


} // namespace SimTK

#endif // SimTK_SimTKCOMMON_PLUGIN_H_