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
  32 // Ugh, I'd much rather this was typesafe, but no time
  33 // to rewrite wxHashTable right now..
  34
  35 typedef wxHashTable wxDLManifest;
  36 typedef wxHashTable wxDLImports;
  37
  38 // ----------------------------------------------------------------------------
  39 // conditional compilation
  40 // ----------------------------------------------------------------------------
  41
  42     // Note: WXPM/EMX has to be tested first, since we want to use
  43     // native version, even if configure detected presence of DLOPEN.
  44
  45 #if defined(__WXPM__) || defined(__EMX__)
  46 #define INCL_DOS
  47 #include <os2.h>
  48     typedef HMODULE wxDllType;
  49 #elif defined(HAVE_DLOPEN)
  50 #include <dlfcn.h>
  51     typedef void *wxDllType;
  52 #elif defined(HAVE_SHL_LOAD)
  53 #include <dl.h>
  54     typedef shl_t wxDllType;
  55 #elif defined(__WINDOWS__)
  56 #include <windows.h>         // needed to get HMODULE
  57     typedef HMODULE wxDllType;
  58 #elif defined(__DARWIN__)
  59     typedef void *wxDllType;
  60 #elif defined(__WXMAC__)
  61     typedef CFragConnectionID wxDllType;
  62 #else
  63 #error "wxLibrary can't be compiled on this platform, sorry."
  64 #endif
  65
  66     // LoadLibrary is defined in windows.h as LoadLibraryA, but wxDllLoader
  67     // method should be called LoadLibrary, not LoadLibraryA or LoadLibraryW!
  68
  69 #if defined(__WIN32__) && defined(LoadLibrary)
  70 #   include "wx/msw/winundef.h"
  71 #endif
  72
  73
  74 // ---------------------------------------------------------------------------
  75 // wxDllLoader
  76 // ---------------------------------------------------------------------------
  77
  78     //  Cross platform wrapper for dlopen and friends.
  79     //  There are no instances of this class, it simply
  80     //  serves as a namespace for its static member functions.
  81
  82 class WXDLLEXPORT wxDllLoader
  83 {
  84 public:
  85
  86         // libname may be either the full path to the file or just the filename
  87         // in which case the library is searched for in all standard locations.
  88         // The platform specific library extension is automatically appended.
  89
  90     static wxDllType    Load(const wxString& name);
  91
  92         // The same as Load, except 'name' is searched for without modification.
  93
  94     static wxDllType    LoadLibrary(const wxString& name);
  95     static void         UnloadLibrary(wxDllType dll);
  96
  97         // return a valid handle for the main program itself or NULL if
  98         // back linking is not supported by the current platform (e.g. Win32)
  99
 100     static wxDllType GetProgramHandle();
 101
 102         // resolve a symbol in a loaded DLL, such as a variable or function
 103         // name.  dllHandle is a handle previously returned by LoadLibrary(),
 104         // symbol is the (possibly mangled) name of the symbol.
 105         // (use extern "C" to export unmangled names)
 106         //
 107         // Since it is perfectly valid for the returned symbol to actually be
 108         // NULL, that is not always indication of an error.  Pass and test the
 109         // parameter 'success' for a true indication of success or failure to
 110         // load the symbol.
 111         //
 112         // Returns a pointer to the symbol on success.
 113
 114     static void *GetSymbol(wxDllType dllHandle, const wxString &name, bool *success = 0);
 115
 116         // return the platform standard DLL extension (with leading dot)
 117
 118     static const wxString &GetDllExt() { return ms_dllext; }
 119
 120 private:
 121
 122     wxDllLoader();                    // forbid construction of objects
 123     static const wxString ms_dllext;  // Platform specific shared lib suffix.
 124 };
 125
 126
 127 // ---------------------------------------------------------------------------
 128 // wxDynamicLibrary
 129 // ---------------------------------------------------------------------------
 130
 131 class wxDLManifestEntry
 132 {
 133 public:
 134
 135     static wxDLImports ms_classes;  // Static hash of all imported classes.
 136
 137     wxDLManifestEntry( const wxString &libname );
 138     ~wxDLManifestEntry();
 139
 140     wxDLManifestEntry  *RefLib() { ++m_linkcount; return this; }
 141     bool                UnrefLib();
 142
 143         // These two are called by the PluginSentinel on (PLUGGABLE) object
 144         // creation/destruction.  There is usually no reason for the user to
 145         // call them directly.  We have to separate this from the link count,
 146         // since the two are not interchangeable.
 147
 148         // FIXME: for even better debugging PluginSentinel should register
 149         //        the name of the class created too, then we can state
 150         //        exactly which object was not destroyed which may be
 151         //        difficult to find otherwise.  Also this code should
 152         //        probably only be active in DEBUG mode, but let's just
 153         //        get it right first.
 154
 155     void        RefObj() { ++m_objcount; }
 156     void        UnrefObj()
 157     {
 158         wxASSERT_MSG( m_objcount > 0, _T("Too many objects deleted??") );
 159         --m_objcount;
 160     }
 161
 162     bool        IsLoaded() const { return m_linkcount > 0; }
 163
 164     wxDllType   GetLinkHandle() const { return m_handle; }
 165     wxDllType   GetProgramHandle() const { return wxDllLoader::GetProgramHandle(); }
 166     void       *GetSymbol(const wxString &symbol, bool *success = 0)
 167     {
 168         return wxDllLoader::GetSymbol( m_handle, symbol, success );
 169     }
 170
 171 private:
 172
 173         // Order of these three *is* important, do not change it
 174
 175     wxClassInfo    *m_before;       // sm_first before loading this lib
 176     wxDllType       m_handle;       // Handle from dlopen.
 177     wxClassInfo    *m_after;        // ..and after.
 178
 179     size_t          m_linkcount;    // Ref count of library link calls
 180     size_t          m_objcount;     // ..and (pluggable) object instantiations.
 181     wxModuleList    m_wxmodules;    // any wxModules that we initialised.
 182
 183     void    UpdateClassInfo();      // Update the wxClassInfo table
 184     void    RestoreClassInfo();     // Restore the original wxClassInfo state.
 185     void    RegisterModules();      // Init any wxModules in the lib.
 186     void    UnregisterModules();    // Cleanup any wxModules we installed.
 187
 188 DECLARE_NO_COPY_CLASS(wxDLManifestEntry)
 189 };
 190
 191
 192 class WXDLLEXPORT wxDynamicLibrary
 193 {
 194 public:
 195
 196         // Static accessors.
 197
 198     static wxDLManifestEntry    *Link(const wxString &libname);
 199     static bool                  Unlink(const wxString &libname);
 200
 201         // Instance methods.
 202
 203     wxDynamicLibrary(const wxString &libname);
 204     ~wxDynamicLibrary();
 205
 206     bool   IsLoaded() const { return m_entry && m_entry->IsLoaded(); }
 207     void  *GetSymbol(const wxString &symbol, bool *success = 0)
 208     {
 209         return m_entry->GetSymbol( symbol, success );
 210     }
 211
 212 private:
 213
 214     static wxDLManifest  ms_manifest;  // Static hash of loaded libs.
 215     wxDLManifestEntry   *m_entry;      // Cache our entry in the manifest.
 216
 217     // We could allow this class to be copied if we really
 218     // wanted to, but not without modification.
 219
 220 DECLARE_NO_COPY_CLASS(wxDynamicLibrary)
 221 };
 222
 223
 224 #endif  // wxUSE_DYNAMIC_LOADER
 225 #endif  // _WX_DYNAMICLOADER_H__
 226
 227 // vi:sts=4:sw=4:et