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_QUIET      = 0x00000020,   // don't log an error if failed to load
  79
  80     wxDL_DEFAULT    = wxDL_NOW      // default flags correspond to Win32
  81 };
  82
  83 enum wxDynamicLibraryCategory
  84 {
  85     wxDL_LIBRARY,       // standard library
  86     wxDL_MODULE         // loadable module/plugin
  87 };
  88
  89 enum wxPluginCategory
  90 {
  91     wxDL_PLUGIN_GUI,    // plugin that uses GUI classes
  92     wxDL_PLUGIN_BASE    // wxBase-only plugin
  93 };
  94
  95 // ----------------------------------------------------------------------------
  96 // macros
  97 // ----------------------------------------------------------------------------
  98
  99 // when loading a function from a DLL you always have to cast the returned
 100 // "void *" pointer to the correct type and, even more annoyingly, you have to
 101 // repeat this type twice if you want to declare and define a function pointer
 102 // all in one line
 103 //
 104 // this macro makes this slightly less painful by allowing you to specify the
 105 // type only once, as the first parameter, and creating a variable of this type
 106 // called "pfn<name>" initialized with the "name" from the "dynlib"
 107 #define wxDYNLIB_FUNCTION(type, name, dynlib) \
 108     type pfn ## name = (type)(dynlib).GetSymbol(_T(#name))
 109
 110
 111 // a more convenient function replacing wxDYNLIB_FUNCTION above
 112 //
 113 // it uses the convention that the type of the function is its name suffixed
 114 // with "_t" but it doesn't define a variable but just assigns the loaded value
 115 // to it and also allows to pass it the prefix to be used instead of hardcoding
 116 // "pfn" (the prefix can be "m_" or "gs_pfn" or whatever)
 117 //
 118 // notice that this function doesn't generate error messages if the symbol
 119 // couldn't be loaded, the caller should generate the appropriate message
 120 #define wxDL_INIT_FUNC(pfx, name, dynlib) \
 121     pfx ## name = (name ## _t)(dynlib).RawGetSymbol(#name)
 122
 123 #ifdef __WXMSW__
 124
 125 // same as wxDL_INIT_FUNC() but appends 'A' or 'W' to the function name, see
 126 // wxDynamicLibrary::GetSymbolAorW()
 127 #define wxDL_INIT_FUNC_AW(pfx, name, dynlib) \
 128     pfx ## name = (name ## _t)(dynlib).GetSymbolAorW(#name)
 129
 130 #endif // __WXMSW__
 131
 132 // the following macros can be used to redirect a whole library to a class and
 133 // check at run-time if the library is present and contains all required
 134 // methods
 135 //
 136 // notice that they are supposed to be used inside a class which has "m_ok"
 137 // member variable indicating if the library had been successfully loaded
 138
 139 // helper macros constructing the name of the variable storing the function
 140 // pointer and the name of its type from the function name
 141 #define wxDL_METHOD_NAME(name) m_pfn ## name
 142 #define wxDL_METHOD_TYPE(name) name ## _t
 143
 144 // parameters are:
 145 //  - rettype: return type of the function, e.g. "int"
 146 //  - name: name of the function, e.g. "foo"
 147 //  - args: function signature in parentheses, e.g. "(int x, int y)"
 148 //  - argnames: the names of the parameters in parentheses, e.g. "(x, y)"
 149 //  - defret: the value to return if the library wasn't successfully loaded
 150 #define wxDL_METHOD_DEFINE( rettype, name, args, argnames, defret ) \
 151     typedef rettype (* wxDL_METHOD_TYPE(name)) args ; \
 152     wxDL_METHOD_TYPE(name) wxDL_METHOD_NAME(name); \
 153     rettype name args \
 154         { return m_ok ? wxDL_METHOD_NAME(name) argnames : defret; }
 155
 156 #define wxDL_VOIDMETHOD_DEFINE( name, args, argnames ) \
 157     typedef void (* wxDL_METHOD_TYPE(name)) args ; \
 158     wxDL_METHOD_TYPE(name) wxDL_METHOD_NAME(name); \
 159     void name args \
 160         { if ( m_ok ) wxDL_METHOD_NAME(name) argnames ; }
 161
 162 #define wxDL_METHOD_LOAD(lib, name) \
 163     wxDL_METHOD_NAME(name) = \
 164         (wxDL_METHOD_TYPE(name)) lib.GetSymbol(#name, &m_ok); \
 165     if ( !m_ok ) return false
 166
 167 // ----------------------------------------------------------------------------
 168 // wxDynamicLibraryDetails: contains details about a loaded wxDynamicLibrary
 169 // ----------------------------------------------------------------------------
 170
 171 class WXDLLIMPEXP_BASE wxDynamicLibraryDetails
 172 {
 173 public:
 174     // ctor, normally never used as these objects are only created by
 175     // wxDynamicLibrary::ListLoaded()
 176     wxDynamicLibraryDetails() { m_address = NULL; m_length = 0; }
 177
 178     // get the (base) name
 179     wxString GetName() const { return m_name; }
 180
 181     // get the full path of this object
 182     wxString GetPath() const { return m_path; }
 183
 184     // get the load address and the extent, return true if this information is
 185     // available
 186     bool GetAddress(void **addr, size_t *len) const
 187     {
 188         if ( !m_address )
 189             return false;
 190
 191         if ( addr )
 192             *addr = m_address;
 193         if ( len )
 194             *len = m_length;
 195
 196         return true;
 197     }
 198
 199     // return the version of the DLL (may be empty if no version info)
 200     wxString GetVersion() const
 201     {
 202         return m_version;
 203     }
 204
 205 private:
 206     wxString m_name,
 207              m_path,
 208              m_version;
 209
 210     void *m_address;
 211     size_t m_length;
 212
 213     friend class wxDynamicLibraryDetailsCreator;
 214 };
 215
 216 WX_DECLARE_USER_EXPORTED_OBJARRAY(wxDynamicLibraryDetails,
 217                                   wxDynamicLibraryDetailsArray,
 218                                   WXDLLIMPEXP_BASE);
 219
 220 // ----------------------------------------------------------------------------
 221 // wxDynamicLibrary: represents a handle to a DLL/shared object
 222 // ----------------------------------------------------------------------------
 223
 224 class WXDLLIMPEXP_BASE wxDynamicLibrary
 225 {
 226 public:
 227     // return a valid handle for the main program itself or NULL if back
 228     // linking is not supported by the current platform (e.g. Win32)
 229     static wxDllType         GetProgramHandle();
 230
 231     // return the platform standard DLL extension (with leading dot)
 232     static const wxString& GetDllExt() { return ms_dllext; }
 233
 234     wxDynamicLibrary() : m_handle(0) { }
 235     wxDynamicLibrary(const wxString& libname, int flags = wxDL_DEFAULT)
 236         : m_handle(0)
 237     {
 238         Load(libname, flags);
 239     }
 240
 241     // NOTE: this class is (deliberately) not virtual, do not attempt
 242     //       to use it polymorphically.
 243     ~wxDynamicLibrary() { Unload(); }
 244
 245     // return true if the library was loaded successfully
 246     bool IsLoaded() const { return m_handle != 0; }
 247
 248     // load the library with the given name (full or not), return true if ok
 249     bool Load(const wxString& libname, int flags = wxDL_DEFAULT);
 250
 251     // raw function for loading dynamic libs: always behaves as if
 252     // wxDL_VERBATIM were specified and doesn't log error message if the
 253     // library couldn't be loaded but simply returns NULL
 254     static wxDllType RawLoad(const wxString& libname, int flags = wxDL_DEFAULT);
 255
 256     // detach the library object from its handle, i.e. prevent the object from
 257     // unloading the library in its dtor -- the caller is now responsible for
 258     // doing this
 259     wxDllType Detach() { wxDllType h = m_handle; m_handle = 0; return h; }
 260
 261     // unload the given library handle (presumably returned by Detach() before)
 262     static void Unload(wxDllType handle);
 263
 264     // unload the library, also done automatically in dtor
 265     void Unload() { if ( IsLoaded() ) { Unload(m_handle); m_handle = 0; } }
 266
 267     // Return the raw handle from dlopen and friends.
 268     wxDllType GetLibHandle() const { return m_handle; }
 269
 270     // check if the given symbol is present in the library, useful to verify if
 271     // a loadable module is our plugin, for example, without provoking error
 272     // messages from GetSymbol()
 273     bool HasSymbol(const wxString& name) const
 274     {
 275         bool ok;
 276         DoGetSymbol(name, &ok);
 277         return ok;
 278     }
 279
 280     // resolve a symbol in a loaded DLL, such as a variable or function name.
 281     // 'name' is the (possibly mangled) name of the symbol. (use extern "C" to
 282     // export unmangled names)
 283     //
 284     // Since it is perfectly valid for the returned symbol to actually be NULL,
 285     // that is not always indication of an error.  Pass and test the parameter
 286     // 'success' for a true indication of success or failure to load the
 287     // symbol.
 288     //
 289     // Returns a pointer to the symbol on success, or NULL if an error occurred
 290     // or the symbol wasn't found.
 291     void *GetSymbol(const wxString& name, bool *success = NULL) const;
 292
 293     // low-level version of GetSymbol()
 294     static void *RawGetSymbol(wxDllType handle, const wxString& name);
 295     void *RawGetSymbol(const wxString& name) const
 296     {
 297 #if defined (__WXPM__) || defined(__EMX__)
 298         return GetSymbol(name);
 299 #else
 300         return RawGetSymbol(m_handle, name);
 301 #endif
 302     }
 303
 304 #ifdef __WXMSW__
 305     // this function is useful for loading functions from the standard Windows
 306     // DLLs: such functions have an 'A' (in ANSI build) or 'W' (in Unicode, or
 307     // wide character build) suffix if they take string parameters
 308     static void *RawGetSymbolAorW(wxDllType handle, const wxString& name)
 309     {
 310         return RawGetSymbol
 311                (
 312                 handle,
 313                 name +
 314 #if wxUSE_UNICODE
 315                 L'W'
 316 #else
 317                 'A'
 318 #endif
 319                );
 320     }
 321
 322     void *GetSymbolAorW(const wxString& name) const
 323     {
 324         return RawGetSymbolAorW(m_handle, name);
 325     }
 326 #endif // __WXMSW__
 327
 328     // return all modules/shared libraries in the address space of this process
 329     //
 330     // returns an empty array if not implemented or an error occurred
 331     static wxDynamicLibraryDetailsArray ListLoaded();
 332
 333     // return platform-specific name of dynamic library with proper extension
 334     // and prefix (e.g. "foo.dll" on Windows or "libfoo.so" on Linux)
 335     static wxString CanonicalizeName(const wxString& name,
 336                                      wxDynamicLibraryCategory cat = wxDL_LIBRARY);
 337
 338     // return name of wxWidgets plugin (adds compiler and version info
 339     // to the filename):
 340     static wxString
 341     CanonicalizePluginName(const wxString& name,
 342                            wxPluginCategory cat = wxDL_PLUGIN_GUI);
 343
 344     // return plugin directory on platforms where it makes sense and empty
 345     // string on others:
 346     static wxString GetPluginsDirectory();
 347
 348
 349 protected:
 350     // common part of GetSymbol() and HasSymbol()
 351     void *DoGetSymbol(const wxString& name, bool *success = 0) const;
 352
 353 #ifdef wxHAVE_DYNLIB_ERROR
 354     // log the error after a dlxxx() function failure
 355     static void Error();
 356 #endif // wxHAVE_DYNLIB_ERROR
 357
 358
 359     // platform specific shared lib suffix.
 360     static const wxString ms_dllext;
 361
 362     // the handle to DLL or NULL
 363     wxDllType m_handle;
 364
 365     // no copy ctor/assignment operators (or we'd try to unload the library
 366     // twice)
 367     DECLARE_NO_COPY_CLASS(wxDynamicLibrary)
 368 };
 369
 370
 371 // ----------------------------------------------------------------------------
 372 // Interesting defines
 373 // ----------------------------------------------------------------------------
 374
 375 #define WXDLL_ENTRY_FUNCTION() \
 376 extern "C" WXEXPORT const wxClassInfo *wxGetClassFirst(); \
 377 const wxClassInfo *wxGetClassFirst() { \
 378   return wxClassInfo::GetFirst(); \
 379 }
 380
 381 #endif // wxUSE_DYNLIB_CLASS
 382
 383 #endif // _WX_DYNLIB_H__