Line data    Source code

       1             : /* Copyright (C) 2014 Wildfire Games.
       2             :  * This file is part of 0 A.D.
       3             :  *
       4             :  * 0 A.D. is free software: you can redistribute it and/or modify
       5             :  * it under the terms of the GNU General Public License as published by
       6             :  * the Free Software Foundation, either version 2 of the License, or
       7             :  * (at your option) any later version.
       8             :  *
       9             :  * 0 A.D. is distributed in the hope that it will be useful,
      10             :  * but WITHOUT ANY WARRANTY; without even the implied warranty of
      11             :  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      12             :  * GNU General Public License for more details.
      13             :  *
      14             :  * You should have received a copy of the GNU General Public License
      15             :  * along with 0 A.D.  If not, see <http://www.gnu.org/licenses/>.
      16             :  */
      17             : 
      18             : #ifndef INCLUDED_DLLLOADER
      19             : #define INCLUDED_DLLLOADER
      20             : 
      21             : #include "ps/Errors.h"
      22             : #include "ps/CLogger.h"
      23             : 
      24           0 : ERROR_GROUP(DllLoader);
      25           0 : ERROR_TYPE(DllLoader, DllNotLoaded);
      26           0 : ERROR_TYPE(DllLoader, SymbolNotFound);
      27             : 
      28             : class DllLoader
      29             : {
      30             : public:
      31             :     /**
      32             :      * Prepare the DLL loader. Does no actual work.
      33             :      *
      34             :      * @param name base name of the library (from which we'll derive
      35             :      *  "name.dll", "libname_dbg.so", etc). Pointer must remain valid for
      36             :      *  this object's lifetime (which is fine if you just use a string literal).
      37             :      * @param loadErrorLogMethod Allows to set the CLogger log level that is
      38             :      *  used when the DllLoader reports loading errors.
      39             :      */
      40             :     DllLoader(const char* name, CLogger::ELogMethod loadErrorLogMethod = CLogger::Error);
      41             : 
      42             :     ~DllLoader();
      43             : 
      44             :     /**
      45             :      * Attempt to load and initialise the library, if not already. Can be harmlessly
      46             :      * called multiple times. Returns false if unsuccessful.
      47             :      */
      48             :     bool LoadDLL();
      49             : 
      50             :     /**
      51             :      * Check whether the library has been loaded successfully. Returns false
      52             :      * before {@link #LoadDLL} has been called; otherwise returns the same as
      53             :      * LoadDLL did.
      54             :      */
      55             :     bool IsLoaded() const;
      56             : 
      57             :     /**
      58             :      * Unload the library, if it has been loaded already. (Usually not needed,
      59             :      * since the destructor will unload it.)
      60             :      */
      61             :     void Unload();
      62             : 
      63             :     /**
      64             :      * Attempt to load a named symbol from the library. If {@link #IsLoaded} is
      65             :      * false, throws PSERROR_DllLoader_DllNotLoaded. If it cannot load the
      66             :      * symbol, throws PSERROR_DllLoader_SymbolNotFound. In both cases, sets fptr
      67             :      * to NULL. Otherwise, fptr is set to point to the loaded function.
      68             :      *
      69             :      * @throws PSERROR_DllLoader
      70             :      */
      71             :     template <typename T>
      72             :     void LoadSymbol(const char* name, T& fptr) const;
      73             : 
      74             :     /**
      75             :      * Override the build-time setting of the directory to search for libraries.
      76             :      */
      77             :     static void OverrideLibdir(const char* libdir);
      78             : 
      79             : private:
      80             :     // Typeless version - the public LoadSymbol hides the slightly ugly
      81             :     // casting from users.
      82             :     void LoadSymbolInternal(const char* name, void** fptr) const;
      83             : 
      84             :     void LogLoadError(const char* errors);
      85             : 
      86             :     const char* m_Name;
      87             :     void* m_Handle;
      88             :     CLogger::ELogMethod m_LoadErrorLogMethod;
      89             : };
      90             : 
      91             : template <typename T>
      92          24 : void DllLoader::LoadSymbol(const char* name, T& fptr) const
      93             : {
      94          24 :     LoadSymbolInternal(name, (void**)&fptr);
      95          24 : }
      96             : 
      97             : #endif // INCLUDED_DLLLOADER