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(__DARWIN__)
  46     // Don't include dlfcn.h on Darwin, we may be using our own replacements.
  47     typedef void               *wxDllType;
  48 #elif defined(HAVE_DLOPEN)
  49     #include <dlfcn.h>
  50     typedef void               *wxDllType;
  51 #elif defined(HAVE_SHL_LOAD)
  52     #include <dl.h>
  53     typedef shl_t               wxDllType;
  54 #elif defined(__WXMAC__)
  55     #include <CodeFragments.h>
  56     typedef CFragConnectionID   wxDllType;
  57 #else
  58     #error "Dynamic Loading classes can't be compiled on this platform, sorry."
  59 #endif
  60
  61 // ----------------------------------------------------------------------------
  62 // constants
  63 // ----------------------------------------------------------------------------
  64
  65 enum wxDLFlags
  66 {
  67     wxDL_LAZY       = 0x00000001,   // resolve undefined symbols at first use
  68                                     // (only works on some Unix versions)
  69     wxDL_NOW        = 0x00000002,   // resolve undefined symbols on load
  70                                     // (default, always the case under Win32)
  71     wxDL_GLOBAL     = 0x00000004,   // export extern symbols to subsequently
  72                                     // loaded libs.
  73     wxDL_VERBATIM   = 0x00000008,   // attempt to load the supplied library
  74                                     // name without appending the usual dll
  75                                     // filename extension.
  76
  77     // this flag is obsolete, don't use
  78     wxDL_NOSHARE    = 0x00000010,   // load new DLL, don't reuse already loaded
  79                                     // (only for wxPluginManager)
  80
  81     wxDL_QUIET      = 0x00000020,   // don't log an error if failed to load
  82
  83     // this flag is dangerous, for internal use of wxMSW only, don't use
  84     wxDL_GET_LOADED = 0x00000040,   // Win32 only: return handle of already
  85                                     // loaded DLL or NULL otherwise; Unload()
  86                                     // should not be called so don't forget to
  87                                     // Detach() if you use this function
  88
  89     wxDL_DEFAULT    = wxDL_NOW      // default flags correspond to Win32
  90 };
  91
  92 enum wxDynamicLibraryCategory
  93 {
  94     wxDL_LIBRARY,       // standard library
  95     wxDL_MODULE         // loadable module/plugin
  96 };
  97
  98 enum wxPluginCategory
  99 {
 100     wxDL_PLUGIN_GUI,    // plugin that uses GUI classes
 101     wxDL_PLUGIN_BASE    // wxBase-only plugin
 102 };
 103
 104 // ----------------------------------------------------------------------------
 105 // macros
 106 // ----------------------------------------------------------------------------
 107
 108 // when loading a function from a DLL you always have to cast the returned
 109 // "void *" pointer to the correct type and, even more annoyingly, you have to
 110 // repeat this type twice if you want to declare and define a function pointer
 111 // all in one line
 112 //
 113 // this macro makes this slightly less painful by allowing you to specify the
 114 // type only once, as the first parameter, and creating a variable of this type
 115 // called "pfn<name>" initialized with the "name" from the "dynlib"
 116 #define wxDYNLIB_FUNCTION(type, name, dynlib) \
 117     type pfn ## name = (type)(dynlib).GetSymbol(_T(#name))
 118
 119
 120 // a more convenient function replacing wxDYNLIB_FUNCTION above
 121 //
 122 // it uses the convention that the type of the function is its name suffixed
 123 // with "_t" but it doesn't define a variable but just assigns the loaded value
 124 // to it and also allows to pass it the prefix to be used instead of hardcoding
 125 // "pfn" (the prefix can be "m_" or "gs_pfn" or whatever)
 126 //
 127 // notice that this function doesn't generate error messages if the symbol
 128 // couldn't be loaded, the caller should generate the appropriate message
 129 #define wxDL_INIT_FUNC(pfx, name, dynlib) \
 130     pfx ## name = (name ## _t)(dynlib).RawGetSymbol(#name)
 131
 132 #ifdef __WXMSW__
 133
 134 // same as wxDL_INIT_FUNC() but appends 'A' or 'W' to the function name, see
 135 // wxDynamicLibrary::GetSymbolAorW()
 136 #define wxDL_INIT_FUNC_AW(pfx, name, dynlib) \
 137     pfx ## name = (name ## _t)(dynlib).GetSymbolAorW(#name)
 138
 139 #endif // __WXMSW__
 140
 141 // the following macros can be used to redirect a whole library to a class and
 142 // check at run-time if the library is present and contains all required
 143 // methods
 144 //
 145 // notice that they are supposed to be used inside a class which has "m_ok"
 146 // member variable indicating if the library had been successfully loaded
 147
 148 // helper macros constructing the name of the variable storing the function
 149 // pointer and the name of its type from the function name
 150 #define wxDL_METHOD_NAME(name) m_pfn ## name
 151 #define wxDL_METHOD_TYPE(name) name ## _t
 152
 153 // parameters are:
 154 //  - rettype: return type of the function, e.g. "int"
 155 //  - name: name of the function, e.g. "foo"
 156 //  - args: function signature in parentheses, e.g. "(int x, int y)"
 157 //  - argnames: the names of the parameters in parentheses, e.g. "(x, y)"
 158 //  - defret: the value to return if the library wasn't successfully loaded
 159 #define wxDL_METHOD_DEFINE( rettype, name, args, argnames, defret ) \
 160     typedef rettype (* wxDL_METHOD_TYPE(name)) args ; \
 161     wxDL_METHOD_TYPE(name) wxDL_METHOD_NAME(name); \
 162     rettype name args \
 163         { return m_ok ? wxDL_METHOD_NAME(name) argnames : defret; }
 164
 165 #define wxDL_VOIDMETHOD_DEFINE( name, args, argnames ) \
 166     typedef void (* wxDL_METHOD_TYPE(name)) args ; \
 167     wxDL_METHOD_TYPE(name) wxDL_METHOD_NAME(name); \
 168     void name args \
 169         { if ( m_ok ) wxDL_METHOD_NAME(name) argnames ; }
 170
 171 #define wxDL_METHOD_LOAD(lib, name) \
 172     wxDL_METHOD_NAME(name) = \
 173         (wxDL_METHOD_TYPE(name)) lib.GetSymbol(#name, &m_ok); \
 174     if ( !m_ok ) return false
 175
 176 // ----------------------------------------------------------------------------
 177 // wxDynamicLibraryDetails: contains details about a loaded wxDynamicLibrary
 178 // ----------------------------------------------------------------------------
 179
 180 class WXDLLIMPEXP_BASE wxDynamicLibraryDetails
 181 {
 182 public:
 183     // ctor, normally never used as these objects are only created by
 184     // wxDynamicLibrary::ListLoaded()
 185     wxDynamicLibraryDetails() { m_address = NULL; m_length = 0; }
 186
 187     // get the (base) name
 188     wxString GetName() const { return m_name; }
 189
 190     // get the full path of this object
 191     wxString GetPath() const { return m_path; }
 192
 193     // get the load address and the extent, return true if this information is
 194     // available
 195     bool GetAddress(void **addr, size_t *len) const
 196     {
 197         if ( !m_address )
 198             return false;
 199
 200         if ( addr )
 201             *addr = m_address;
 202         if ( len )
 203             *len = m_length;
 204
 205         return true;
 206     }
 207
 208     // return the version of the DLL (may be empty if no version info)
 209     wxString GetVersion() const
 210     {
 211         return m_version;
 212     }
 213
 214 private:
 215     wxString m_name,
 216              m_path,
 217              m_version;
 218
 219     void *m_address;
 220     size_t m_length;
 221
 222     friend class wxDynamicLibraryDetailsCreator;
 223 };
 224
 225 WX_DECLARE_USER_EXPORTED_OBJARRAY(wxDynamicLibraryDetails,
 226                                   wxDynamicLibraryDetailsArray,
 227                                   WXDLLIMPEXP_BASE);
 228
 229 // ----------------------------------------------------------------------------
 230 // wxDynamicLibrary: represents a handle to a DLL/shared object
 231 // ----------------------------------------------------------------------------
 232
 233 class WXDLLIMPEXP_BASE wxDynamicLibrary
 234 {
 235 public:
 236     // return a valid handle for the main program itself or NULL if back
 237     // linking is not supported by the current platform (e.g. Win32)
 238     static wxDllType         GetProgramHandle();
 239
 240     // return the platform standard DLL extension (with leading dot)
 241     static const wxString& GetDllExt() { return ms_dllext; }
 242
 243     wxDynamicLibrary() : m_handle(0) { }
 244     wxDynamicLibrary(const wxString& libname, int flags = wxDL_DEFAULT)
 245         : m_handle(0)
 246     {
 247         Load(libname, flags);
 248     }
 249
 250     // NOTE: this class is (deliberately) not virtual, do not attempt
 251     //       to use it polymorphically.
 252     ~wxDynamicLibrary() { Unload(); }
 253
 254     // return true if the library was loaded successfully
 255     bool IsLoaded() const { return m_handle != 0; }
 256
 257     // load the library with the given name (full or not), return true if ok
 258     bool Load(const wxString& libname, int flags = wxDL_DEFAULT);
 259
 260     // raw function for loading dynamic libs: always behaves as if
 261     // wxDL_VERBATIM were specified and doesn't log error message if the
 262     // library couldn't be loaded but simply returns NULL
 263     static wxDllType RawLoad(const wxString& libname, int flags = wxDL_DEFAULT);
 264
 265     // detach the library object from its handle, i.e. prevent the object from
 266     // unloading the library in its dtor -- the caller is now responsible for
 267     // doing this
 268     wxDllType Detach() { wxDllType h = m_handle; m_handle = 0; return h; }
 269
 270     // unload the given library handle (presumably returned by Detach() before)
 271     static void Unload(wxDllType handle);
 272
 273     // unload the library, also done automatically in dtor
 274     void Unload() { if ( IsLoaded() ) { Unload(m_handle); m_handle = 0; } }
 275
 276     // Return the raw handle from dlopen and friends.
 277     wxDllType GetLibHandle() const { return m_handle; }
 278
 279     // check if the given symbol is present in the library, useful to verify if
 280     // a loadable module is our plugin, for example, without provoking error
 281     // messages from GetSymbol()
 282     bool HasSymbol(const wxString& name) const
 283     {
 284         bool ok;
 285         DoGetSymbol(name, &ok);
 286         return ok;
 287     }
 288
 289     // resolve a symbol in a loaded DLL, such as a variable or function name.
 290     // 'name' is the (possibly mangled) name of the symbol. (use extern "C" to
 291     // export unmangled names)
 292     //
 293     // Since it is perfectly valid for the returned symbol to actually be NULL,
 294     // that is not always indication of an error.  Pass and test the parameter
 295     // 'success' for a true indication of success or failure to load the
 296     // symbol.
 297     //
 298     // Returns a pointer to the symbol on success, or NULL if an error occurred
 299     // or the symbol wasn't found.
 300     void *GetSymbol(const wxString& name, bool *success = NULL) const;
 301
 302     // low-level version of GetSymbol()
 303     static void *RawGetSymbol(wxDllType handle, const wxString& name);
 304     void *RawGetSymbol(const wxString& name) const
 305     {
 306 #if defined (__WXPM__) || defined(__EMX__)
 307         return GetSymbol(name);
 308 #else
 309         return RawGetSymbol(m_handle, name);
 310 #endif
 311     }
 312
 313 #ifdef __WXMSW__
 314     // this function is useful for loading functions from the standard Windows
 315     // DLLs: such functions have an 'A' (in ANSI build) or 'W' (in Unicode, or
 316     // wide character build) suffix if they take string parameters
 317     static void *RawGetSymbolAorW(wxDllType handle, const wxString& name)
 318     {
 319         return RawGetSymbol
 320                (
 321                 handle,
 322                 name +
 323 #if wxUSE_UNICODE
 324                 L'W'
 325 #else
 326                 'A'
 327 #endif
 328                );
 329     }
 330
 331     void *GetSymbolAorW(const wxString& name) const
 332     {
 333         return RawGetSymbolAorW(m_handle, name);
 334     }
 335 #endif // __WXMSW__
 336
 337     // return all modules/shared libraries in the address space of this process
 338     //
 339     // returns an empty array if not implemented or an error occurred
 340     static wxDynamicLibraryDetailsArray ListLoaded();
 341
 342     // return platform-specific name of dynamic library with proper extension
 343     // and prefix (e.g. "foo.dll" on Windows or "libfoo.so" on Linux)
 344     static wxString CanonicalizeName(const wxString& name,
 345                                      wxDynamicLibraryCategory cat = wxDL_LIBRARY);
 346
 347     // return name of wxWidgets plugin (adds compiler and version info
 348     // to the filename):
 349     static wxString
 350     CanonicalizePluginName(const wxString& name,
 351                            wxPluginCategory cat = wxDL_PLUGIN_GUI);
 352
 353     // return plugin directory on platforms where it makes sense and empty
 354     // string on others:
 355     static wxString GetPluginsDirectory();
 356
 357
 358 protected:
 359     // common part of GetSymbol() and HasSymbol()
 360     void *DoGetSymbol(const wxString& name, bool *success = 0) const;
 361
 362 #ifdef wxHAVE_DYNLIB_ERROR
 363     // log the error after a dlxxx() function failure
 364     static void Error();
 365 #endif // wxHAVE_DYNLIB_ERROR
 366
 367
 368     // platform specific shared lib suffix.
 369     static const wxString ms_dllext;
 370
 371     // the handle to DLL or NULL
 372     wxDllType m_handle;
 373
 374     // no copy ctor/assignment operators (or we'd try to unload the library
 375     // twice)
 376     DECLARE_NO_COPY_CLASS(wxDynamicLibrary)
 377 };
 378
 379
 380 // ----------------------------------------------------------------------------
 381 // Interesting defines
 382 // ----------------------------------------------------------------------------
 383
 384 #define WXDLL_ENTRY_FUNCTION() \
 385 extern "C" WXEXPORT const wxClassInfo *wxGetClassFirst(); \
 386 const wxClassInfo *wxGetClassFirst() { \
 387   return wxClassInfo::GetFirst(); \
 388 }
 389
 390 #endif // wxUSE_DYNLIB_CLASS
 391
 392 #endif // _WX_DYNLIB_H__