include/wx/dynlib.h

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        wx/dynlib.h
   3 // Purpose:     Dynamic library loading classes
   4 // Author:      Guilhem Lavaux, Vadim Zeitlin, Vaclav Slavik
   5 // Modified by:
   6 // Created:     20/07/98
   7 // RCS-ID:      $Id$
   8 // Copyright:   (c) 1998 Guilhem Lavaux
   9 // Licence:     wxWindows licence
  10 /////////////////////////////////////////////////////////////////////////////
  11
  12 #ifndef _WX_DYNLIB_H__
  13 #define _WX_DYNLIB_H__
  14
  15 #include "wx/defs.h"
  16
  17 #if wxUSE_DYNLIB_CLASS
  18
  19 #include "wx/string.h"
  20 #include "wx/dynarray.h"
  21
  22 #if defined(__OS2__) || defined(__EMX__)
  23 #include "wx/os2/private.h"
  24 #endif
  25
  26 #ifdef __WXMSW__
  27 #include "wx/msw/private.h"
  28 #endif
  29
  30 // note that we have our own dlerror() implementation under Darwin
  31 #if (defined(HAVE_DLERROR) && !defined(__EMX__)) || defined(__DARWIN__)
  32     #define wxHAVE_DYNLIB_ERROR
  33 #endif
  34
  35 class WXDLLIMPEXP_FWD_BASE wxDynamicLibraryDetailsCreator;
  36
  37 // ----------------------------------------------------------------------------
  38 // conditional compilation
  39 // ----------------------------------------------------------------------------
  40
  41 // Note: __OS2__/EMX has to be tested first, since we want to use
  42 // native version, even if configure detected presence of DLOPEN.
  43 #if defined(__OS2__) || defined(__EMX__) || defined(__WINDOWS__)
  44     typedef HMODULE             wxDllType;
  45 #elif defined(HAVE_DLOPEN)
  46     #include <dlfcn.h>
  47     typedef void               *wxDllType;
  48 #elif defined(HAVE_SHL_LOAD)
  49     #include <dl.h>
  50     typedef shl_t               wxDllType;
  51 #elif defined(__DARWIN__)
  52     typedef void               *wxDllType;
  53 #elif defined(__WXMAC__)
  54     #include <CodeFragments.h>
  55     typedef CFragConnectionID   wxDllType;
  56 #else
  57     #error "Dynamic Loading classes can't be compiled on this platform, sorry."
  58 #endif
  59
  60 // ----------------------------------------------------------------------------
  61 // constants
  62 // ----------------------------------------------------------------------------
  63
  64 enum wxDLFlags
  65 {
  66     wxDL_LAZY       = 0x00000001,   // resolve undefined symbols at first use
  67                                     // (only works on some Unix versions)
  68     wxDL_NOW        = 0x00000002,   // resolve undefined symbols on load
  69                                     // (default, always the case under Win32)
  70     wxDL_GLOBAL     = 0x00000004,   // export extern symbols to subsequently
  71                                     // loaded libs.
  72     wxDL_VERBATIM   = 0x00000008,   // attempt to load the supplied library
  73                                     // name without appending the usual dll
  74                                     // filename extension.
  75     wxDL_NOSHARE    = 0x00000010,   // load new DLL, don't reuse already loaded
  76                                     // (only for wxPluginManager)
  77
  78     wxDL_DEFAULT    = wxDL_NOW      // default flags correspond to Win32
  79 };
  80
  81 enum wxDynamicLibraryCategory
  82 {
  83     wxDL_LIBRARY,       // standard library
  84     wxDL_MODULE         // loadable module/plugin
  85 };
  86
  87 enum wxPluginCategory
  88 {
  89     wxDL_PLUGIN_GUI,    // plugin that uses GUI classes
  90     wxDL_PLUGIN_BASE    // wxBase-only plugin
  91 };
  92
  93 // ----------------------------------------------------------------------------
  94 // macros
  95 // ----------------------------------------------------------------------------
  96
  97 // when loading a function from a DLL you always have to cast the returned
  98 // "void *" pointer to the correct type and, even more annoyingly, you have to
  99 // repeat this type twice if you want to declare and define a function pointer
 100 // all in one line
 101 //
 102 // this macro makes this slightly less painful by allowing you to specify the
 103 // type only once, as the first parameter, and creating a variable of this type
 104 // called "pfn<name>" initialized with the "name" from the "dynlib"
 105 #define wxDYNLIB_FUNCTION(type, name, dynlib) \
 106     type pfn ## name = (type)(dynlib).GetSymbol(_T(#name))
 107
 108
 109 // a more convenient function replacing wxDYNLIB_FUNCTION above
 110 //
 111 // it uses the convention that the type of the function is its name suffixed
 112 // with "_t" but it doesn't define a variable but just assigns the loaded value
 113 // to it and also allows to pass it the prefix to be used instead of hardcoding
 114 // "pfn" (the prefix can be "m_" or "gs_pfn" or whatever)
 115 #define wxDL_INIT_FUNC(pfx, name, dynlib) \
 116     pfx ## name = (name ## _t)(dynlib).GetSymbol(#name)
 117
 118 #ifdef __WXMSW__
 119
 120 // same as wxDL_INIT_FUNC() but appends 'A' or 'W' to the function name, see
 121 // wxDynamicLibrary::GetSymbolAorW()
 122 #define wxDL_INIT_FUNC_AW(pfx, name, dynlib) \
 123     pfx ## name = (name ## _t)(dynlib).GetSymbolAorW(#name)
 124
 125 #endif // __WXMSW__
 126
 127 // the following macros can be used to redirect a whole library to a class and
 128 // check at run-time if the library is present and contains all required
 129 // methods
 130 //
 131 // notice that they are supposed to be used inside a class which has "m_ok"
 132 // member variable indicating if the library had been successfully loaded
 133
 134 // helper macros constructing the name of the variable storing the function
 135 // pointer and the name of its type from the function name
 136 #define wxDL_METHOD_NAME(name) m_pfn ## name
 137 #define wxDL_METHOD_TYPE(name) name ## _t
 138
 139 // parameters are:
 140 //  - rettype: return type of the function, e.g. "int"
 141 //  - name: name of the function, e.g. "foo"
 142 //  - args: function signature in parentheses, e.g. "(int x, int y)"
 143 //  - argnames: the names of the parameters in parentheses, e.g. "(x, y)"
 144 //  - defret: the value to return if the library wasn't successfully loaded
 145 #define wxDL_METHOD_DEFINE( rettype, name, args, argnames, defret ) \
 146     typedef rettype (* wxDL_METHOD_TYPE(name)) args ; \
 147     wxDL_METHOD_TYPE(name) wxDL_METHOD_NAME(name); \
 148     rettype name args \
 149         { return m_ok ? wxDL_METHOD_NAME(name) argnames : defret; }
 150
 151 #define wxDL_VOIDMETHOD_DEFINE( name, args, argnames ) \
 152     typedef void (* wxDL_METHOD_TYPE(name)) args ; \
 153     wxDL_METHOD_TYPE(name) wxDL_METHOD_NAME(name); \
 154     void name args \
 155         { if ( m_ok ) wxDL_METHOD_NAME(name) argnames ; }
 156
 157 #define wxDL_METHOD_LOAD(lib, name) \
 158     wxDL_METHOD_NAME(name) = \
 159         (wxDL_METHOD_TYPE(name)) lib.GetSymbol(#name, &m_ok); \
 160     if ( !m_ok ) return false
 161
 162 // ----------------------------------------------------------------------------
 163 // wxDynamicLibraryDetails: contains details about a loaded wxDynamicLibrary
 164 // ----------------------------------------------------------------------------
 165
 166 class WXDLLIMPEXP_BASE wxDynamicLibraryDetails
 167 {
 168 public:
 169     // ctor, normally never used as these objects are only created by
 170     // wxDynamicLibrary::ListLoaded()
 171     wxDynamicLibraryDetails() { m_address = NULL; m_length = 0; }
 172
 173     // get the (base) name
 174     wxString GetName() const { return m_name; }
 175
 176     // get the full path of this object
 177     wxString GetPath() const { return m_path; }
 178
 179     // get the load address and the extent, return true if this information is
 180     // available
 181     bool GetAddress(void **addr, size_t *len) const
 182     {
 183         if ( !m_address )
 184             return false;
 185
 186         if ( addr )
 187             *addr = m_address;
 188         if ( len )
 189             *len = m_length;
 190
 191         return true;
 192     }
 193
 194     // return the version of the DLL (may be empty if no version info)
 195     wxString GetVersion() const
 196     {
 197         return m_version;
 198     }
 199
 200 private:
 201     wxString m_name,
 202              m_path,
 203              m_version;
 204
 205     void *m_address;
 206     size_t m_length;
 207
 208     friend class wxDynamicLibraryDetailsCreator;
 209 };
 210
 211 WX_DECLARE_USER_EXPORTED_OBJARRAY(wxDynamicLibraryDetails,
 212                                   wxDynamicLibraryDetailsArray,
 213                                   WXDLLIMPEXP_BASE);
 214
 215 // ----------------------------------------------------------------------------
 216 // wxDynamicLibrary: represents a handle to a DLL/shared object
 217 // ----------------------------------------------------------------------------
 218
 219 class WXDLLIMPEXP_BASE wxDynamicLibrary
 220 {
 221 public:
 222     // return a valid handle for the main program itself or NULL if back
 223     // linking is not supported by the current platform (e.g. Win32)
 224     static wxDllType         GetProgramHandle();
 225
 226     // return the platform standard DLL extension (with leading dot)
 227     static const wxString& GetDllExt() { return ms_dllext; }
 228
 229     wxDynamicLibrary() : m_handle(0) { }
 230     wxDynamicLibrary(const wxString& libname, int flags = wxDL_DEFAULT)
 231         : m_handle(0)
 232     {
 233         Load(libname, flags);
 234     }
 235
 236     // NOTE: this class is (deliberately) not virtual, do not attempt
 237     //       to use it polymorphically.
 238     ~wxDynamicLibrary() { Unload(); }
 239
 240     // return true if the library was loaded successfully
 241     bool IsLoaded() const { return m_handle != 0; }
 242
 243     // load the library with the given name (full or not), return true if ok
 244     bool Load(const wxString& libname, int flags = wxDL_DEFAULT);
 245
 246     // raw function for loading dynamic libs: always behaves as if
 247     // wxDL_VERBATIM were specified and doesn't log error message if the
 248     // library couldn't be loaded but simply returns NULL
 249     static wxDllType RawLoad(const wxString& libname, int flags = wxDL_DEFAULT);
 250
 251     // detach the library object from its handle, i.e. prevent the object from
 252     // unloading the library in its dtor -- the caller is now responsible for
 253     // doing this
 254     wxDllType Detach() { wxDllType h = m_handle; m_handle = 0; return h; }
 255
 256     // unload the given library handle (presumably returned by Detach() before)
 257     static void Unload(wxDllType handle);
 258
 259     // unload the library, also done automatically in dtor
 260     void Unload() { if ( IsLoaded() ) { Unload(m_handle); m_handle = 0; } }
 261
 262     // Return the raw handle from dlopen and friends.
 263     wxDllType GetLibHandle() const { return m_handle; }
 264
 265     // check if the given symbol is present in the library, useful to verify if
 266     // a loadable module is our plugin, for example, without provoking error
 267     // messages from GetSymbol()
 268     bool HasSymbol(const wxString& name) const
 269     {
 270         bool ok;
 271         DoGetSymbol(name, &ok);
 272         return ok;
 273     }
 274
 275     // resolve a symbol in a loaded DLL, such as a variable or function name.
 276     // 'name' is the (possibly mangled) name of the symbol. (use extern "C" to
 277     // export unmangled names)
 278     //
 279     // Since it is perfectly valid for the returned symbol to actually be NULL,
 280     // that is not always indication of an error.  Pass and test the parameter
 281     // 'success' for a true indication of success or failure to load the
 282     // symbol.
 283     //
 284     // Returns a pointer to the symbol on success, or NULL if an error occurred
 285     // or the symbol wasn't found.
 286     void *GetSymbol(const wxString& name, bool *success = NULL) const;
 287
 288     // low-level version of GetSymbol()
 289     static void *RawGetSymbol(wxDllType handle, const wxString& name);
 290     void *RawGetSymbol(const wxString& name) const
 291     {
 292 #if defined (__WXPM__) || defined(__EMX__)
 293         return GetSymbol(name);
 294 #else
 295         return RawGetSymbol(m_handle, name);
 296 #endif
 297     }
 298
 299 #ifdef __WXMSW__
 300     // this function is useful for loading functions from the standard Windows
 301     // DLLs: such functions have an 'A' (in ANSI build) or 'W' (in Unicode, or
 302     // wide character build) suffix if they take string parameters
 303     static void *RawGetSymbolAorW(wxDllType handle, const wxString& name)
 304     {
 305         return RawGetSymbol
 306                (
 307                 handle,
 308                 name +
 309 #if wxUSE_UNICODE
 310                 L'W'
 311 #else
 312                 'A'
 313 #endif
 314                );
 315     }
 316
 317     void *GetSymbolAorW(const wxString& name) const
 318     {
 319         return RawGetSymbolAorW(m_handle, name);
 320     }
 321 #endif // __WXMSW__
 322
 323     // return all modules/shared libraries in the address space of this process
 324     //
 325     // returns an empty array if not implemented or an error occurred
 326     static wxDynamicLibraryDetailsArray ListLoaded();
 327
 328     // return platform-specific name of dynamic library with proper extension
 329     // and prefix (e.g. "foo.dll" on Windows or "libfoo.so" on Linux)
 330     static wxString CanonicalizeName(const wxString& name,
 331                                      wxDynamicLibraryCategory cat = wxDL_LIBRARY);
 332
 333     // return name of wxWidgets plugin (adds compiler and version info
 334     // to the filename):
 335     static wxString
 336     CanonicalizePluginName(const wxString& name,
 337                            wxPluginCategory cat = wxDL_PLUGIN_GUI);
 338
 339     // return plugin directory on platforms where it makes sense and empty
 340     // string on others:
 341     static wxString GetPluginsDirectory();
 342
 343
 344 protected:
 345     // common part of GetSymbol() and HasSymbol()
 346     void *DoGetSymbol(const wxString& name, bool *success = 0) const;
 347
 348 #ifdef wxHAVE_DYNLIB_ERROR
 349     // log the error after a dlxxx() function failure
 350     static void Error();
 351 #endif // wxHAVE_DYNLIB_ERROR
 352
 353
 354     // platform specific shared lib suffix.
 355     static const wxString ms_dllext;
 356
 357     // the handle to DLL or NULL
 358     wxDllType m_handle;
 359
 360     // no copy ctor/assignment operators (or we'd try to unload the library
 361     // twice)
 362     DECLARE_NO_COPY_CLASS(wxDynamicLibrary)
 363 };
 364
 365
 366 // ----------------------------------------------------------------------------
 367 // Interesting defines
 368 // ----------------------------------------------------------------------------
 369
 370 #define WXDLL_ENTRY_FUNCTION() \
 371 extern "C" WXEXPORT const wxClassInfo *wxGetClassFirst(); \
 372 const wxClassInfo *wxGetClassFirst() { \
 373   return wxClassInfo::GetFirst(); \
 374 }
 375
 376 #endif // wxUSE_DYNLIB_CLASS
 377
 378 #endif // _WX_DYNLIB_H__