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