source/utils/CarlaLibUtils.hpp

   1 /*
   2  * Carla library utils
   3  * Copyright (C) 2011-2022 Filipe Coelho <falktx@falktx.com>
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License as
   7  * published by the Free Software Foundation; either version 2 of
   8  * the License, or any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * For a full copy of the GNU General Public License see the doc/GPL.txt file.
  16  */
  17
  18 #ifndef CARLA_LIB_UTILS_HPP_INCLUDED
  19 #define CARLA_LIB_UTILS_HPP_INCLUDED
  20
  21 #include "CarlaUtils.hpp"
  22
  23 #ifdef CARLA_OS_WIN
  24 typedef HMODULE lib_t;
  25 #else
  26 # include <dlfcn.h>
  27 typedef void* lib_t;
  28 #endif
  29
  30 // -----------------------------------------------------------------------
  31 // library related calls
  32
  33 /*
  34  * Open 'filename' library (must not be null).
  35  * May return null, in which case "lib_error" has the error.
  36  */
  37 static inline
  38 lib_t lib_open(const char* const filename, const bool global = false) noexcept
  39 {
  40     CARLA_SAFE_ASSERT_RETURN(filename != nullptr && filename[0] != '\0', nullptr);
  41
  42     try {
  43 #ifdef CARLA_OS_WIN
  44         return ::LoadLibraryA(filename);
  45         // unused
  46         (void)global;
  47 #else
  48         return ::dlopen(filename, RTLD_NOW|(global ? RTLD_GLOBAL : RTLD_LOCAL));
  49 #endif
  50     } CARLA_SAFE_EXCEPTION_RETURN("lib_open", nullptr);
  51 }
  52
  53 /*
  54  * Close a previously opened library (must not be null).
  55  * If false is returned, "lib_error" has the error.
  56  */
  57 static inline
  58 bool lib_close(const lib_t lib) noexcept
  59 {
  60     CARLA_SAFE_ASSERT_RETURN(lib != nullptr, false);
  61
  62     try {
  63 #ifdef CARLA_OS_WIN
  64         return ::FreeLibrary(lib);
  65 #else
  66         return (::dlclose(lib) == 0);
  67 #endif
  68     } CARLA_SAFE_EXCEPTION_RETURN("lib_close", false);
  69 }
  70
  71 /*
  72  * Get a library symbol (must not be null) as a function.
  73  * Returns null if the symbol is not found.
  74  */
  75 template<typename Func>
  76 static inline
  77 Func lib_symbol(const lib_t lib, const char* const symbol) noexcept
  78 {
  79     CARLA_SAFE_ASSERT_RETURN(lib != nullptr, nullptr);
  80     CARLA_SAFE_ASSERT_RETURN(symbol != nullptr && symbol[0] != '\0', nullptr);
  81
  82     try {
  83 #ifdef CARLA_OS_WIN
  84 # if defined(__GNUC__) && (__GNUC__ >= 9)
  85 #  pragma GCC diagnostic push
  86 #  pragma GCC diagnostic ignored "-Wcast-function-type"
  87 # endif
  88         return reinterpret_cast<Func>(::GetProcAddress(lib, symbol));
  89 # if defined(__GNUC__) && (__GNUC__ >= 9)
  90 #  pragma GCC diagnostic pop
  91 # endif
  92 #else
  93         return reinterpret_cast<Func>(::dlsym(lib, symbol));
  94 #endif
  95     } CARLA_SAFE_EXCEPTION_RETURN("lib_symbol", nullptr);
  96 }
  97
  98 /*
  99  * Return the last operation error ('filename' must not be null).
 100  * May return null.
 101  */
 102 static inline
 103 const char* lib_error(const char* const filename) noexcept
 104 {
 105     CARLA_SAFE_ASSERT_RETURN(filename != nullptr && filename[0] != '\0', nullptr);
 106
 107 #ifdef CARLA_OS_WIN
 108     static char libError[2048+1];
 109     carla_zeroChars(libError, 2048+1);
 110
 111     try {
 112         const DWORD winErrorCode  = ::GetLastError();
 113         const int   winErrorFlags = FORMAT_MESSAGE_ALLOCATE_BUFFER|FORMAT_MESSAGE_FROM_SYSTEM|FORMAT_MESSAGE_IGNORE_INSERTS;
 114         LPVOID      winErrorString;
 115
 116         ::FormatMessage(winErrorFlags, nullptr, winErrorCode, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), (LPTSTR)&winErrorString, 0, nullptr);
 117
 118         std::snprintf(libError, 2048, "%s: error code %li: %s", filename, winErrorCode, (const char*)winErrorString);
 119         ::LocalFree(winErrorString);
 120     } CARLA_SAFE_EXCEPTION("lib_error");
 121
 122     return (libError[0] != '\0') ? libError : nullptr;
 123 #else
 124     return ::dlerror();
 125 #endif
 126 }
 127
 128 // -----------------------------------------------------------------------
 129
 130 #endif // CARLA_LIB_UTILS_HPP_INCLUDED