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 licence
  11 /////////////////////////////////////////////////////////////////////////////
  12
  13 #ifndef _WX_DYNAMICLOADER_H__
  14 #define _WX_DYNAMICLOADER_H__
  15
  16 #if defined(__GNUG__) && !defined(__APPLE__)
  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/hashmap.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 class WXDLLEXPORT wxPluginLibrary;
  42
  43 WX_DECLARE_EXPORTED_STRING_HASH_MAP(wxPluginLibrary *, wxDLManifest);
  44 typedef wxDLManifest wxDLImports;
  45
  46 // ----------------------------------------------------------------------------
  47 // conditional compilation
  48 // ----------------------------------------------------------------------------
  49
  50     // Note: WXPM/EMX has to be tested first, since we want to use
  51     // native version, even if configure detected presence of DLOPEN.
  52
  53 #if defined(__WXPM__) || defined(__EMX__) || defined(__WINDOWS__)
  54 typedef HMODULE             wxDllType;
  55 #elif defined(HAVE_DLOPEN)
  56 #include <dlfcn.h>
  57 typedef void               *wxDllType;
  58 #elif defined(HAVE_SHL_LOAD)
  59 #include <dl.h>
  60 typedef shl_t               wxDllType;
  61 #elif defined(__DARWIN__)
  62 typedef void               *wxDllType;
  63 #elif defined(__WXMAC__)
  64 typedef CFragConnectionID   wxDllType;
  65 #else
  66 #error "Dynamic Loading classes can't be compiled on this platform, sorry."
  67 #endif
  68
  69
  70 // ---------------------------------------------------------------------------
  71 // wxDynamicLibrary
  72 // ---------------------------------------------------------------------------
  73
  74 //FIXME:  This class isn't really common at all, it should be moved
  75 //        into platform dependent files.
  76
  77 // NOTE: this class is (deliberately) not virtual, do not attempt
  78 //       to use it polymorphically.
  79
  80 enum wxDLFlags
  81 {
  82     wxDL_LAZY       = 0x00000001,   // resolve undefined symbols at first use
  83     wxDL_NOW        = 0x00000002,   // resolve undefined symbols on load
  84     wxDL_GLOBAL     = 0x00000004,   // export extern symbols to subsequently
  85                                     // loaded libs.
  86     wxDL_VERBATIM   = 0x00000008,   // Attempt to load the supplied library
  87                                     // name without appending the usual dll
  88                                     // filename extension.
  89
  90     wxDL_NOSHARE    = 0x00000010,   // load new DLL, don't reuse already loaded
  91
  92     // FIXME: why? (VZ)
  93 #ifdef __osf__
  94     wxDL_DEFAULT    = wxDL_LAZY
  95 #else
  96     wxDL_DEFAULT    = wxDL_LAZY | wxDL_GLOBAL
  97 #endif
  98 };
  99
 100
 101 class WXDLLEXPORT wxDynamicLibrary
 102 {
 103 public:
 104
 105         // return a valid handle for the main program itself or NULL if
 106         // back linking is not supported by the current platform (e.g. Win32)
 107
 108     static wxDllType         GetProgramHandle();
 109
 110         // return the platform standard DLL extension (with leading dot)
 111
 112     static const wxChar *GetDllExt() { return ms_dllext; }
 113
 114     wxDynamicLibrary() : m_handle(0) {}
 115     wxDynamicLibrary(wxString libname, int flags = wxDL_DEFAULT)
 116         : m_handle(0)
 117     {
 118         Load(libname, flags);
 119     }
 120     ~wxDynamicLibrary() { Unload(); }
 121
 122         // return TRUE if the library was loaded successfully
 123
 124     bool IsLoaded() const { return m_handle != 0; }
 125
 126         // load the library with the given name
 127         // (full or not), return TRUE on success
 128
 129     bool Load(wxString libname, int flags = wxDL_DEFAULT);
 130
 131         // detach the library object from its handle, i.e. prevent the object
 132         // from unloading the library in its dtor -- the caller is now
 133         // responsible for doing this
 134     wxDllType Detach() { wxDllType h = m_handle; m_handle = 0; return h; }
 135
 136         // unload the library, also done automatically in dtor
 137
 138     void Unload();
 139
 140         // Return the raw handle from dlopen and friends.
 141
 142     wxDllType GetLibHandle() const { return m_handle; }
 143
 144         // resolve a symbol in a loaded DLL, such as a variable or function
 145         // name.  'name' is the (possibly mangled) name of the symbol.
 146         // (use extern "C" to export unmangled names)
 147         //
 148         // Since it is perfectly valid for the returned symbol to actually be
 149         // NULL, that is not always indication of an error.  Pass and test the
 150         // parameter 'success' for a true indication of success or failure to
 151         // load the symbol.
 152         //
 153         // Returns a pointer to the symbol on success, or NULL if an error
 154         // occurred or the symbol wasn't found.
 155
 156     void *GetSymbol(const wxString& name, bool *success = 0) const;
 157
 158 #if WXWIN_COMPATIBILITY_2_2
 159     operator bool() const { return IsLoaded(); }
 160 #endif
 161
 162 protected:
 163
 164         // Platform specific shared lib suffix.
 165
 166     static const wxChar *ms_dllext;
 167
 168         // the handle to DLL or NULL
 169
 170     wxDllType m_handle;
 171
 172         // no copy ctor/assignment operators
 173         // or we'd try to unload the library twice
 174
 175     DECLARE_NO_COPY_CLASS(wxDynamicLibrary)
 176 };
 177
 178
 179 // ---------------------------------------------------------------------------
 180 // wxPluginLibrary
 181 // ---------------------------------------------------------------------------
 182
 183 // NOTE: Do not attempt to use a base class pointer to this class.
 184 //       wxDL is not virtual and we deliberately hide some of it's
 185 //       methods here.
 186 //
 187 //       Unless you know exacty why you need to, you probably shouldn't
 188 //       instantiate this class directly anyway, use wxPluginManager
 189 //       instead.
 190
 191 class WXDLLEXPORT wxPluginLibrary : public wxDynamicLibrary
 192 {
 193 public:
 194
 195     static wxDLImports* ms_classes;  // Static hash of all imported classes.
 196
 197     wxPluginLibrary( const wxString &libname, int flags = wxDL_DEFAULT );
 198     ~wxPluginLibrary();
 199
 200     wxPluginLibrary  *RefLib();
 201     bool              UnrefLib();
 202
 203         // These two are called by the PluginSentinel on (PLUGGABLE) object
 204         // creation/destruction.  There is usually no reason for the user to
 205         // call them directly.  We have to separate this from the link count,
 206         // since the two are not interchangeable.
 207
 208         // FIXME: for even better debugging PluginSentinel should register
 209         //        the name of the class created too, then we can state
 210         //        exactly which object was not destroyed which may be
 211         //        difficult to find otherwise.  Also this code should
 212         //        probably only be active in DEBUG mode, but let's just
 213         //        get it right first.
 214
 215     void  RefObj() { ++m_objcount; }
 216     void  UnrefObj()
 217     {
 218         wxASSERT_MSG( m_objcount > 0, _T("Too many objects deleted??") );
 219         --m_objcount;
 220     }
 221
 222         // Override/hide some base class methods
 223
 224     bool  IsLoaded() const { return m_linkcount > 0; }
 225     void  Unload() { UnrefLib(); }
 226
 227 private:
 228
 229     wxClassInfo    *m_before;       // sm_first before loading this lib
 230     wxClassInfo    *m_after;        // ..and after.
 231
 232     size_t          m_linkcount;    // Ref count of library link calls
 233     size_t          m_objcount;     // ..and (pluggable) object instantiations.
 234     wxModuleList    m_wxmodules;    // any wxModules that we initialised.
 235
 236     void    UpdateClassInfo();      // Update the wxClassInfo table
 237     void    RestoreClassInfo();     // Restore the original wxClassInfo state.
 238     void    RegisterModules();      // Init any wxModules in the lib.
 239     void    UnregisterModules();    // Cleanup any wxModules we installed.
 240
 241     DECLARE_NO_COPY_CLASS(wxPluginLibrary)
 242 };
 243
 244
 245 class WXDLLEXPORT wxPluginManager
 246 {
 247 public:
 248
 249         // Static accessors.
 250
 251     static wxPluginLibrary    *LoadLibrary( const wxString &libname,
 252                                             int flags = wxDL_DEFAULT );
 253     static bool                UnloadLibrary(const wxString &libname);
 254
 255         // This is used by wxDllLoader.  It's wrapped in the compatibility
 256         // macro because it's of arguable use outside of that.
 257
 258 #if WXWIN_COMPATIBILITY_2_2
 259     static wxPluginLibrary *GetObjectFromHandle(wxDllType handle);
 260 #endif
 261
 262         // Instance methods.
 263
 264     wxPluginManager() : m_entry(NULL) {};
 265     wxPluginManager(const wxString &libname, int flags = wxDL_DEFAULT)
 266     {
 267         Load(libname, flags);
 268     }
 269     ~wxPluginManager() { Unload(); }
 270
 271     bool   Load(const wxString &libname, int flags = wxDL_DEFAULT);
 272     void   Unload();
 273
 274     bool   IsLoaded() const { return m_entry && m_entry->IsLoaded(); }
 275     void  *GetSymbol(const wxString &symbol, bool *success = 0)
 276     {
 277         return m_entry->GetSymbol( symbol, success );
 278     }
 279
 280     static void CreateManifest() { ms_manifest = new wxDLManifest(wxKEY_STRING); }
 281     static void ClearManifest() { delete ms_manifest; ms_manifest = NULL; }
 282
 283 private:
 284     // return the pointer to the entry for the library with given name in
 285     // ms_manifest or NULL if none
 286     static wxPluginLibrary *FindByName(const wxString& name)
 287     {
 288         const wxDLManifest::iterator i = ms_manifest->find(name);
 289
 290         return i == ms_manifest->end() ? NULL : i->second;
 291     }
 292
 293     static wxDLManifest* ms_manifest;  // Static hash of loaded libs.
 294     wxPluginLibrary*     m_entry;      // Cache our entry in the manifest.
 295
 296     // We could allow this class to be copied if we really
 297     // wanted to, but not without modification.
 298     DECLARE_NO_COPY_CLASS(wxPluginManager)
 299 };
 300
 301
 302 // ---------------------------------------------------------------------------
 303 // wxDllLoader
 304 // ---------------------------------------------------------------------------
 305
 306     //  Cross platform wrapper for dlopen and friends.
 307     //  There are no instances of this class, it simply
 308     //  serves as a namespace for its static member functions.
 309
 310 #if WXWIN_COMPATIBILITY_2_2
 311 class WXDLLEXPORT wxDllLoader
 312 {
 313 public:
 314
 315     static wxDllType    LoadLibrary(const wxString& name, bool *success = NULL);
 316     static void         UnloadLibrary(wxDllType dll);
 317
 318     static wxDllType GetProgramHandle() { return wxDynamicLibrary::GetProgramHandle(); }
 319
 320     static void *GetSymbol(wxDllType dllHandle, const wxString &name, bool *success = 0);
 321
 322     static wxString GetDllExt() { return wxDynamicLibrary::GetDllExt(); }
 323
 324 private:
 325
 326     wxDllLoader();                    // forbid construction of objects
 327 };
 328 #endif
 329
 330 #endif  // wxUSE_DYNAMIC_LOADER
 331 #endif  // _WX_DYNAMICLOADER_H__
 332