src/common/dynload.cpp

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:         src/common/dynload.cpp
   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 licence
  11 /////////////////////////////////////////////////////////////////////////////
  12
  13 // ----------------------------------------------------------------------------
  14 // headers
  15 // ----------------------------------------------------------------------------
  16
  17 #include "wx/wxprec.h"
  18
  19 #ifdef __BORLANDC__
  20     #pragma hdrstop
  21 #endif
  22
  23 #if wxUSE_DYNAMIC_LOADER
  24
  25 #ifdef __WINDOWS__
  26     #include "wx/msw/private.h"
  27 #endif
  28
  29 #ifndef WX_PRECOMP
  30     #include "wx/log.h"
  31     #include "wx/intl.h"
  32     #include "wx/hash.h"
  33     #include "wx/utils.h"
  34     #include "wx/module.h"
  35 #endif
  36
  37 #include "wx/strconv.h"
  38
  39 #include "wx/dynload.h"
  40
  41
  42 // ---------------------------------------------------------------------------
  43 // wxPluginLibrary
  44 // ---------------------------------------------------------------------------
  45
  46
  47 wxDLImports*  wxPluginLibrary::ms_classes = NULL;
  48
  49 class wxPluginLibraryModule : public wxModule
  50 {
  51 public:
  52     wxPluginLibraryModule() { }
  53
  54     // TODO: create ms_classes on demand, why always preallocate it?
  55     virtual bool OnInit()
  56     {
  57         wxPluginLibrary::ms_classes = new wxDLImports;
  58         wxPluginManager::CreateManifest();
  59         return true;
  60     }
  61
  62     virtual void OnExit()
  63     {
  64         wxDELETE(wxPluginLibrary::ms_classes);
  65         wxPluginManager::ClearManifest();
  66     }
  67
  68 private:
  69     DECLARE_DYNAMIC_CLASS(wxPluginLibraryModule )
  70 };
  71
  72 IMPLEMENT_DYNAMIC_CLASS(wxPluginLibraryModule, wxModule)
  73
  74
  75 wxPluginLibrary::wxPluginLibrary(const wxString &libname, int flags)
  76         : m_linkcount(1)
  77         , m_objcount(0)
  78 {
  79     const wxClassInfo* const oldFirst = wxClassInfo::GetFirst();
  80     Load( libname, flags );
  81
  82     // It is simple to know what is the first object in the linked list of
  83     // wxClassInfo that we registered (it's also the last one chronologically),
  84     // it's just the new head of the wxClassInfo list:
  85     m_ourFirst = wxClassInfo::GetFirst();
  86
  87     // But to find the first wxClassInfo created by this library we need to
  88     // iterate until we get to the previous head as we don't have the links in
  89     // the backwards direction:
  90     if ( m_ourFirst != oldFirst )
  91     {
  92         for ( const wxClassInfo* info = m_ourFirst; ; info = info->GetNext() )
  93         {
  94             if ( info->GetNext() == oldFirst )
  95             {
  96                 m_ourLast = info;
  97                 break;
  98             }
  99         }
 100     }
 101     else // We didn't register any classes at all.
 102     {
 103         m_ourFirst =
 104         m_ourLast = NULL;
 105     }
 106
 107     if( m_handle != 0 )
 108     {
 109         UpdateClasses();
 110         RegisterModules();
 111     }
 112     else
 113     {
 114         // Flag us for deletion
 115         --m_linkcount;
 116     }
 117 }
 118
 119 wxPluginLibrary::~wxPluginLibrary()
 120 {
 121     if( m_handle != 0 )
 122     {
 123         UnregisterModules();
 124         RestoreClasses();
 125     }
 126 }
 127
 128 wxPluginLibrary *wxPluginLibrary::RefLib()
 129 {
 130     wxCHECK_MSG( m_linkcount > 0, NULL,
 131                  wxT("Library had been already deleted!") );
 132
 133     ++m_linkcount;
 134     return this;
 135 }
 136
 137 bool wxPluginLibrary::UnrefLib()
 138 {
 139     wxASSERT_MSG( m_objcount == 0,
 140                   wxT("Library unloaded before all objects were destroyed") );
 141
 142     if ( m_linkcount == 0 || --m_linkcount == 0 )
 143     {
 144         delete this;
 145         return true;
 146     }
 147
 148     return false;
 149 }
 150
 151 // ------------------------
 152 // Private methods
 153 // ------------------------
 154
 155 void wxPluginLibrary::UpdateClasses()
 156 {
 157     if ( !m_ourFirst )
 158         return;
 159
 160     for ( const wxClassInfo *info = m_ourFirst; ; info = info->GetNext() )
 161     {
 162         if( info->GetClassName() )
 163         {
 164             // Hash all the class names into a local table too so
 165             // we can quickly find the entry they correspond to.
 166             (*ms_classes)[info->GetClassName()] = this;
 167         }
 168
 169         if ( info == m_ourLast )
 170             break;
 171     }
 172 }
 173
 174 void wxPluginLibrary::RestoreClasses()
 175 {
 176     // Check if there is a need to restore classes.
 177     if (!ms_classes)
 178         return;
 179
 180     if ( !m_ourFirst )
 181         return;
 182
 183     for ( const wxClassInfo *info = m_ourFirst; ; info = info->GetNext() )
 184     {
 185         ms_classes->erase(ms_classes->find(info->GetClassName()));
 186
 187         if ( info == m_ourLast )
 188             break;
 189     }
 190 }
 191
 192 void wxPluginLibrary::RegisterModules()
 193 {
 194     // Plugin libraries might have wxModules, Register and initialise them if
 195     // they do.
 196     //
 197     // Note that these classes are NOT included in the reference counting since
 198     // it's implicit that they will be unloaded if and when the last handle to
 199     // the library is.  We do have to keep a copy of the module's pointer
 200     // though, as there is currently no way to Unregister it without it.
 201
 202     wxASSERT_MSG( m_linkcount == 1,
 203                   wxT("RegisterModules should only be called for the first load") );
 204
 205     if ( m_ourFirst )
 206     {
 207         for ( const wxClassInfo *info = m_ourFirst; ; info = info->GetNext() )
 208         {
 209             if( info->IsKindOf(wxCLASSINFO(wxModule)) )
 210             {
 211                 wxModule *m = wxDynamicCast(info->CreateObject(), wxModule);
 212
 213                 wxASSERT_MSG( m, wxT("wxDynamicCast of wxModule failed") );
 214
 215                 m_wxmodules.push_back(m);
 216                 wxModule::RegisterModule(m);
 217             }
 218
 219             if ( info == m_ourLast )
 220                 break;
 221         }
 222     }
 223
 224     // FIXME: Likewise this is (well was) very similar to InitializeModules()
 225
 226     for ( wxModuleList::iterator it = m_wxmodules.begin();
 227           it != m_wxmodules.end();
 228           ++it)
 229     {
 230         if( !(*it)->Init() )
 231         {
 232             wxLogDebug(wxT("wxModule::Init() failed for wxPluginLibrary"));
 233
 234             // XXX: Watch this, a different hash implementation might break it,
 235             //      a good hash implementation would let us fix it though.
 236
 237             // The name of the game is to remove any uninitialised modules and
 238             // let the dtor Exit the rest on shutdown, (which we'll initiate
 239             // shortly).
 240
 241             wxModuleList::iterator oldNode = m_wxmodules.end();
 242             do {
 243                 ++it;
 244                 if( oldNode != m_wxmodules.end() )
 245                     m_wxmodules.erase(oldNode);
 246                 wxModule::UnregisterModule( *it );
 247                 oldNode = it;
 248             } while( it != m_wxmodules.end() );
 249
 250             --m_linkcount;     // Flag us for deletion
 251             break;
 252         }
 253     }
 254 }
 255
 256 void wxPluginLibrary::UnregisterModules()
 257 {
 258     wxModuleList::iterator it;
 259
 260     for ( it = m_wxmodules.begin(); it != m_wxmodules.end(); ++it )
 261         (*it)->Exit();
 262
 263     for ( it = m_wxmodules.begin(); it != m_wxmodules.end(); ++it )
 264         wxModule::UnregisterModule( *it );
 265
 266     // NB: content of the list was deleted by UnregisterModule calls above:
 267     m_wxmodules.clear();
 268 }
 269
 270
 271 // ---------------------------------------------------------------------------
 272 // wxPluginManager
 273 // ---------------------------------------------------------------------------
 274
 275 wxDLManifest*   wxPluginManager::ms_manifest = NULL;
 276
 277 // ------------------------
 278 // Static accessors
 279 // ------------------------
 280
 281 wxPluginLibrary *
 282 wxPluginManager::LoadLibrary(const wxString &libname, int flags)
 283 {
 284     wxString realname(libname);
 285
 286     if( !(flags & wxDL_VERBATIM) )
 287         realname += wxDynamicLibrary::GetDllExt(wxDL_MODULE);
 288
 289     wxPluginLibrary *entry;
 290
 291     if ( flags & wxDL_NOSHARE )
 292     {
 293         entry = NULL;
 294     }
 295     else
 296     {
 297         entry = FindByName(realname);
 298     }
 299
 300     if ( entry )
 301     {
 302         wxLogTrace(wxT("dll"),
 303                    wxT("LoadLibrary(%s): already loaded."), realname.c_str());
 304
 305         entry->RefLib();
 306     }
 307     else
 308     {
 309         entry = new wxPluginLibrary( libname, flags );
 310
 311         if ( entry->IsLoaded() )
 312         {
 313             (*ms_manifest)[realname] = entry;
 314
 315             wxLogTrace(wxT("dll"),
 316                        wxT("LoadLibrary(%s): loaded ok."), realname.c_str());
 317
 318         }
 319         else
 320         {
 321             wxLogTrace(wxT("dll"),
 322                        wxT("LoadLibrary(%s): failed to load."), realname.c_str());
 323
 324             // we have created entry just above
 325             if ( !entry->UnrefLib() )
 326             {
 327                 // ... so UnrefLib() is supposed to delete it
 328                 wxFAIL_MSG( wxT("Currently linked library is not loaded?") );
 329             }
 330
 331             entry = NULL;
 332         }
 333     }
 334
 335     return entry;
 336 }
 337
 338 bool wxPluginManager::UnloadLibrary(const wxString& libname)
 339 {
 340     wxString realname = libname;
 341
 342     wxPluginLibrary *entry = FindByName(realname);
 343
 344     if ( !entry )
 345     {
 346         realname += wxDynamicLibrary::GetDllExt(wxDL_MODULE);
 347
 348         entry = FindByName(realname);
 349     }
 350
 351     if ( !entry )
 352     {
 353         wxLogDebug(wxT("Attempt to unload library '%s' which is not loaded."),
 354                    libname.c_str());
 355
 356         return false;
 357     }
 358
 359     wxLogTrace(wxT("dll"), wxT("UnloadLibrary(%s)"), realname.c_str());
 360
 361     if ( !entry->UnrefLib() )
 362     {
 363         // not really unloaded yet
 364         return false;
 365     }
 366
 367     ms_manifest->erase(ms_manifest->find(realname));
 368
 369     return true;
 370 }
 371
 372 // ------------------------
 373 // Class implementation
 374 // ------------------------
 375
 376 bool wxPluginManager::Load(const wxString &libname, int flags)
 377 {
 378     m_entry = wxPluginManager::LoadLibrary(libname, flags);
 379
 380     return IsLoaded();
 381 }
 382
 383 void wxPluginManager::Unload()
 384 {
 385     wxCHECK_RET( m_entry, wxT("unloading an invalid wxPluginManager?") );
 386
 387     for ( wxDLManifest::iterator i = ms_manifest->begin();
 388           i != ms_manifest->end();
 389           ++i )
 390     {
 391         if ( i->second == m_entry )
 392         {
 393             ms_manifest->erase(i);
 394             break;
 395         }
 396     }
 397
 398     m_entry->UnrefLib();
 399
 400     m_entry = NULL;
 401 }
 402
 403 #endif  // wxUSE_DYNAMIC_LOADER