include/wx/dynload.h

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:         dynload.h
   3 // Purpose:      Dynamic loading framework
   4 // Author:       Ron Lee, David Falkinder, Vadim Zeitlin and a cast of 1000's
   5 //               (derived in part from dynlib.cpp (c) 1998 Guilhem Lavaux)
   6 // Modified by:
   7 // Created:      03/12/01
   8 // RCS-ID:       $Id$
   9 // Copyright:    (c) 2001 Ron Lee <ron@debian.org>
  10 // Licence:      wxWindows license
  11 /////////////////////////////////////////////////////////////////////////////
  12
  13 #ifndef _WX_DYNAMICLOADER_H__
  14 #define _WX_DYNAMICLOADER_H__
  15
  16 #ifdef __GNUG__
  17 #pragma interface "dynload.h"
  18 #endif
  19
  20 // ----------------------------------------------------------------------------
  21 // headers
  22 // ----------------------------------------------------------------------------
  23
  24 #include "wx/defs.h"
  25
  26 #if wxUSE_DYNAMIC_LOADER
  27
  28 #include "wx/hash.h"
  29 #include "wx/module.h"
  30
  31 // FIXME: can this go in private.h or something too??
  32 #if defined(__WXPM__) || defined(__EMX__)
  33 #define INCL_DOS
  34 #include <os2.h>
  35 #endif
  36
  37 #ifdef __WXMSW__
  38 #include "wx/msw/private.h"
  39 #endif
  40
  41 // Ugh, I'd much rather this was typesafe, but no time
  42 // to rewrite wxHashTable right now..
  43
  44 typedef wxHashTable wxDLManifest;
  45 typedef wxHashTable wxDLImports;
  46
  47 // ----------------------------------------------------------------------------
  48 // conditional compilation
  49 // ----------------------------------------------------------------------------
  50
  51     // Note: WXPM/EMX has to be tested first, since we want to use
  52     // native version, even if configure detected presence of DLOPEN.
  53
  54 #if defined(__WXPM__) || defined(__EMX__) || defined(__WINDOWS__)
  55 typedef HMODULE             wxDllType;
  56 #elif defined(HAVE_DLOPEN)
  57 #include <dlfcn.h>
  58 typedef void               *wxDllType;
  59 #elif defined(HAVE_SHL_LOAD)
  60 #include <dl.h>
  61 typedef shl_t               wxDllType;
  62 #elif defined(__DARWIN__)
  63 typedef void               *wxDllType;
  64 #elif defined(__WXMAC__)
  65 typedef CFragConnectionID   wxDllType;
  66 #else
  67 #error "Dynamic Loading classes can't be compiled on this platform, sorry."
  68 #endif
  69
  70
  71 // ---------------------------------------------------------------------------
  72 // wxDynamicLibrary
  73 // ---------------------------------------------------------------------------
  74
  75 //FIXME:  This class isn't really common at all, it should be moved
  76 //        into platform dependent files.
  77
  78 // NOTE: this class is (deliberately) not virtual, do not attempt
  79 //       to use it polymorphically.
  80
  81 enum wxDLFlags
  82 {
  83     wxDL_LAZY       = 0x00000001,   // resolve undefined symbols at first use
  84     wxDL_NOW        = 0x00000002,   // resolve undefined symbols on load
  85     wxDL_GLOBAL     = 0x00000004,   // export extern symbols to subsequently
  86                                     // loaded libs.
  87     wxDL_VERBATIM   = 0x00000008,   // Attempt to load the supplied library
  88                                     // name without appending the usual dll
  89                                     // filename extension.
  90
  91     wxDL_NOSHARE    = 0x00000010,   // load new DLL, don't reuse already loaded
  92
  93     // FIXME: why? (VZ)
  94 #ifdef __osf__
  95     wxDL_DEFAULT    = wxDL_LAZY
  96 #else
  97     wxDL_DEFAULT    = wxDL_LAZY | wxDL_GLOBAL
  98 #endif
  99 };
 100
 101
 102 class WXDLLEXPORT wxDynamicLibrary
 103 {
 104 public:
 105
 106         // return a valid handle for the main program itself or NULL if
 107         // back linking is not supported by the current platform (e.g. Win32)
 108
 109     static wxDllType         GetProgramHandle();
 110
 111         // return the platform standard DLL extension (with leading dot)
 112
 113     static const wxChar *GetDllExt() { return ms_dllext; }
 114
 115     wxDynamicLibrary() : m_handle(0) {}
 116     wxDynamicLibrary(wxString libname, int flags = wxDL_DEFAULT)
 117         : m_handle(0)
 118     {
 119         Load(libname, flags);
 120     }
 121     ~wxDynamicLibrary() { Unload(); }
 122
 123         // return TRUE if the library was loaded successfully
 124
 125     bool IsLoaded() const { return m_handle != 0; }
 126
 127         // load the library with the given name
 128         // (full or not), return TRUE on success
 129
 130     bool Load(wxString libname, int flags = wxDL_DEFAULT);
 131
 132         // unload the library, also done automatically in dtor
 133
 134     void Unload();
 135
 136         // Return the raw handle from dlopen and friends.
 137
 138     wxDllType GetLibHandle() const { return m_handle; }
 139
 140         // resolve a symbol in a loaded DLL, such as a variable or function
 141         // name.  'name' is the (possibly mangled) name of the symbol.
 142         // (use extern "C" to export unmangled names)
 143         //
 144         // Since it is perfectly valid for the returned symbol to actually be
 145         // NULL, that is not always indication of an error.  Pass and test the
 146         // parameter 'success' for a true indication of success or failure to
 147         // load the symbol.
 148         //
 149         // Returns a pointer to the symbol on success, or NULL if an error
 150         // occurred or the symbol wasn't found.
 151
 152     void *GetSymbol(const wxString& name, bool *success = 0) const;
 153
 154 #if WXWIN_COMPATIBILITY_2_2
 155     operator bool() const { return IsLoaded(); }
 156 #endif
 157
 158 protected:
 159
 160         // Platform specific shared lib suffix.
 161
 162     static const wxChar *ms_dllext;
 163
 164         // the handle to DLL or NULL
 165
 166     wxDllType m_handle;
 167
 168         // no copy ctor/assignment operators
 169         // or we'd try to unload the library twice
 170
 171 DECLARE_NO_COPY_CLASS(wxDynamicLibrary)
 172 };
 173
 174
 175 // ---------------------------------------------------------------------------
 176 // wxPluginLibrary
 177 // ---------------------------------------------------------------------------
 178
 179 // NOTE: Do not attempt to use a base class pointer to this class.
 180 //       wxDL is not virtual and we deliberately hide some of it's
 181 //       methods here.
 182 //
 183 //       Unless you know exacty why you need to, you probably shouldn't
 184 //       instantiate this class directly anyway, use wxPluginManager
 185 //       instead.
 186
 187 class WXDLLEXPORT wxPluginLibrary : public wxDynamicLibrary
 188 {
 189 public:
 190
 191     static wxDLImports* ms_classes;  // Static hash of all imported classes.
 192
 193     wxPluginLibrary( const wxString &libname, int flags = wxDL_DEFAULT );
 194     ~wxPluginLibrary();
 195
 196     wxPluginLibrary  *RefLib();
 197     bool              UnrefLib();
 198
 199         // These two are called by the PluginSentinel on (PLUGGABLE) object
 200         // creation/destruction.  There is usually no reason for the user to
 201         // call them directly.  We have to separate this from the link count,
 202         // since the two are not interchangeable.
 203
 204         // FIXME: for even better debugging PluginSentinel should register
 205         //        the name of the class created too, then we can state
 206         //        exactly which object was not destroyed which may be
 207         //        difficult to find otherwise.  Also this code should
 208         //        probably only be active in DEBUG mode, but let's just
 209         //        get it right first.
 210
 211     void  RefObj() { ++m_objcount; }
 212     void  UnrefObj()
 213     {
 214         wxASSERT_MSG( m_objcount > 0, _T("Too many objects deleted??") );
 215         --m_objcount;
 216     }
 217
 218         // Override/hide some base class methods
 219
 220     bool  IsLoaded() const { return m_linkcount > 0; }
 221     void  Unload() { UnrefLib(); }
 222
 223 private:
 224
 225     wxClassInfo    *m_before;       // sm_first before loading this lib
 226     wxClassInfo    *m_after;        // ..and after.
 227
 228     size_t          m_linkcount;    // Ref count of library link calls
 229     size_t          m_objcount;     // ..and (pluggable) object instantiations.
 230     wxModuleList    m_wxmodules;    // any wxModules that we initialised.
 231
 232     void    UpdateClassInfo();      // Update the wxClassInfo table
 233     void    RestoreClassInfo();     // Restore the original wxClassInfo state.
 234     void    RegisterModules();      // Init any wxModules in the lib.
 235     void    UnregisterModules();    // Cleanup any wxModules we installed.
 236
 237 DECLARE_NO_COPY_CLASS(wxPluginLibrary)
 238 };
 239
 240
 241 class WXDLLEXPORT wxPluginManager
 242 {
 243 public:
 244
 245         // Static accessors.
 246
 247     static wxPluginLibrary    *LoadLibrary( const wxString &libname,
 248                                             int flags = wxDL_DEFAULT );
 249     static bool                UnloadLibrary(const wxString &libname);
 250
 251         // This is used by wxDllLoader.  It's wrapped in the compatibility
 252         // macro because it's of arguable use outside of that.
 253
 254 #if WXWIN_COMPATIBILITY_2_2
 255     static wxPluginLibrary *GetObjectFromHandle(wxDllType handle);
 256 #endif
 257
 258         // Instance methods.
 259
 260     wxPluginManager() : m_entry(0) {};
 261     wxPluginManager(const wxString &libname, int flags = wxDL_DEFAULT)
 262     {
 263         Load(libname, flags);
 264     }
 265     ~wxPluginManager() { Unload(); }
 266
 267     bool   Load(const wxString &libname, int flags = wxDL_DEFAULT);
 268     void   Unload();
 269
 270     bool   IsLoaded() const { return m_entry && m_entry->IsLoaded(); }
 271     void  *GetSymbol(const wxString &symbol, bool *success = 0)
 272     {
 273         return m_entry->GetSymbol( symbol, success );
 274     }
 275
 276     static void CreateManifest() { ms_manifest = new wxDLManifest(wxKEY_STRING); }
 277     static void ClearManifest() { delete ms_manifest; ms_manifest = NULL; }
 278
 279 private:
 280
 281     static wxDLManifest* ms_manifest;  // Static hash of loaded libs.
 282     wxPluginLibrary*     m_entry;      // Cache our entry in the manifest.
 283
 284     // We could allow this class to be copied if we really
 285     // wanted to, but not without modification.
 286
 287 DECLARE_NO_COPY_CLASS(wxPluginManager)
 288 };
 289
 290
 291 // ---------------------------------------------------------------------------
 292 // wxDllLoader
 293 // ---------------------------------------------------------------------------
 294
 295     //  Cross platform wrapper for dlopen and friends.
 296     //  There are no instances of this class, it simply
 297     //  serves as a namespace for its static member functions.
 298
 299 #if WXWIN_COMPATIBILITY_2_2
 300 class WXDLLEXPORT wxDllLoader
 301 {
 302 public:
 303
 304     static wxDllType    LoadLibrary(const wxString& name);
 305     static void         UnloadLibrary(wxDllType dll);
 306
 307     static wxDllType GetProgramHandle() { return wxDynamicLibrary::GetProgramHandle(); }
 308
 309     static void *GetSymbol(wxDllType dllHandle, const wxString &name, bool *success = 0);
 310
 311     static wxString GetDllExt() { return wxDynamicLibrary::GetDllExt(); }
 312
 313 private:
 314
 315     wxDllLoader();                    // forbid construction of objects
 316 };
 317 #endif
 318
 319 #endif  // wxUSE_DYNAMIC_LOADER
 320 #endif  // _WX_DYNAMICLOADER_H__
 321