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