wxWidgets/include/wx/dynlib.h
Vadim Zeitlin ced3df7730 wxDL_XXX macros and dynamic loading cleanup:
1. Clearly document the wxDL_XXX macros; including their implicit usage
   of m_ok member variable
2. Made sure they're used in the same way in all places they are used
   (sometimes they were passed an object, sometimes a pointer, breaking
   compilation: see patch 1791288)
3. Don't allocate wxDynamicLibrary objects on heap unnecessarily (which
   removes the need to delete -- or leak, as it was -- them afterwards)
4. Some naming convention fixes



git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@48625 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
2007-09-10 10:49:55 +00:00

361 lines
12 KiB
C++

/////////////////////////////////////////////////////////////////////////////
// Name: wx/dynlib.h
// Purpose: Dynamic library loading classes
// Author: Guilhem Lavaux, Vadim Zeitlin, Vaclav Slavik
// Modified by:
// Created: 20/07/98
// RCS-ID: $Id$
// Copyright: (c) 1998 Guilhem Lavaux
// Licence: wxWindows licence
/////////////////////////////////////////////////////////////////////////////
#ifndef _WX_DYNLIB_H__
#define _WX_DYNLIB_H__
#include "wx/defs.h"
#if wxUSE_DYNLIB_CLASS
#include "wx/string.h"
#include "wx/dynarray.h"
#if defined(__OS2__) || defined(__EMX__)
#include "wx/os2/private.h"
#endif
#ifdef __WXMSW__
#include "wx/msw/private.h"
#endif
// note that we have our own dlerror() implementation under Darwin
#if (defined(HAVE_DLERROR) && !defined(__EMX__)) || defined(__DARWIN__)
#define wxHAVE_DYNLIB_ERROR
#endif
class WXDLLIMPEXP_FWD_BASE wxDynamicLibraryDetailsCreator;
// ----------------------------------------------------------------------------
// conditional compilation
// ----------------------------------------------------------------------------
// Note: __OS2__/EMX has to be tested first, since we want to use
// native version, even if configure detected presence of DLOPEN.
#if defined(__OS2__) || defined(__EMX__) || defined(__WINDOWS__)
typedef HMODULE wxDllType;
#elif defined(HAVE_DLOPEN)
#include <dlfcn.h>
typedef void *wxDllType;
#elif defined(HAVE_SHL_LOAD)
#include <dl.h>
typedef shl_t wxDllType;
#elif defined(__DARWIN__)
typedef void *wxDllType;
#elif defined(__WXMAC__)
#include <CodeFragments.h>
typedef CFragConnectionID wxDllType;
#else
#error "Dynamic Loading classes can't be compiled on this platform, sorry."
#endif
// ----------------------------------------------------------------------------
// constants
// ----------------------------------------------------------------------------
enum wxDLFlags
{
wxDL_LAZY = 0x00000001, // resolve undefined symbols at first use
// (only works on some Unix versions)
wxDL_NOW = 0x00000002, // resolve undefined symbols on load
// (default, always the case under Win32)
wxDL_GLOBAL = 0x00000004, // export extern symbols to subsequently
// loaded libs.
wxDL_VERBATIM = 0x00000008, // attempt to load the supplied library
// name without appending the usual dll
// filename extension.
wxDL_NOSHARE = 0x00000010, // load new DLL, don't reuse already loaded
// (only for wxPluginManager)
wxDL_DEFAULT = wxDL_NOW // default flags correspond to Win32
};
enum wxDynamicLibraryCategory
{
wxDL_LIBRARY, // standard library
wxDL_MODULE // loadable module/plugin
};
enum wxPluginCategory
{
wxDL_PLUGIN_GUI, // plugin that uses GUI classes
wxDL_PLUGIN_BASE // wxBase-only plugin
};
// ----------------------------------------------------------------------------
// macros
// ----------------------------------------------------------------------------
// when loading a function from a DLL you always have to cast the returned
// "void *" pointer to the correct type and, even more annoyingly, you have to
// repeat this type twice if you want to declare and define a function pointer
// all in one line
//
// this macro makes this slightly less painful by allowing you to specify the
// type only once, as the first parameter, and creating a variable of this type
// called "pfn<name>" initialized with the "name" from the "dynlib"
#define wxDYNLIB_FUNCTION(type, name, dynlib) \
type pfn ## name = (type)(dynlib).GetSymbol(_T(#name))
// the following macros can be used to redirect a whole library to a class and
// check at run-time if the library is present and contains all required
// methods
//
// notice that they are supposed to be used inside a class which has "m_ok"
// member variable indicating if the library had been successfully loaded
// helper macros constructing the name of the variable storing the function
// pointer and the name of its type from the function name
#define wxDL_METHOD_NAME(name) m_pfn ## name
#define wxDL_METHOD_TYPE(name) name ## _t
// parameters are:
// - rettype: return type of the function, e.g. "int"
// - name: name of the function, e.g. "foo"
// - args: function signature in parentheses, e.g. "(int x, int y)"
// - argnames: the names of the parameters in parentheses, e.g. "(x, y)"
// - defret: the value to return if the library wasn't successfully loaded
#define wxDL_METHOD_DEFINE( rettype, name, args, argnames, defret ) \
typedef rettype (* wxDL_METHOD_TYPE(name)) args ; \
wxDL_METHOD_TYPE(name) wxDL_METHOD_NAME(name); \
rettype name args \
{ return m_ok ? wxDL_METHOD_NAME(name) argnames : defret; }
#define wxDL_VOIDMETHOD_DEFINE( name, args, argnames ) \
typedef void (* wxDL_METHOD_TYPE(name)) args ; \
wxDL_METHOD_TYPE(name) wxDL_METHOD_NAME(name); \
void name args \
{ if ( m_ok ) wxDL_METHOD_NAME(name) argnames ; }
#define wxDL_METHOD_LOAD(lib, name) \
wxDL_METHOD_NAME(name) = \
(wxDL_METHOD_TYPE(name)) lib.GetSymbol(#name, &m_ok); \
if ( !m_ok ) return false
// ----------------------------------------------------------------------------
// wxDynamicLibraryDetails: contains details about a loaded wxDynamicLibrary
// ----------------------------------------------------------------------------
class WXDLLIMPEXP_BASE wxDynamicLibraryDetails
{
public:
// ctor, normally never used as these objects are only created by
// wxDynamicLibrary::ListLoaded()
wxDynamicLibraryDetails() { m_address = NULL; m_length = 0; }
// get the (base) name
wxString GetName() const { return m_name; }
// get the full path of this object
wxString GetPath() const { return m_path; }
// get the load address and the extent, return true if this information is
// available
bool GetAddress(void **addr, size_t *len) const
{
if ( !m_address )
return false;
if ( addr )
*addr = m_address;
if ( len )
*len = m_length;
return true;
}
// return the version of the DLL (may be empty if no version info)
wxString GetVersion() const
{
return m_version;
}
private:
wxString m_name,
m_path,
m_version;
void *m_address;
size_t m_length;
friend class wxDynamicLibraryDetailsCreator;
};
WX_DECLARE_USER_EXPORTED_OBJARRAY(wxDynamicLibraryDetails,
wxDynamicLibraryDetailsArray,
WXDLLIMPEXP_BASE);
// ----------------------------------------------------------------------------
// wxDynamicLibrary: represents a handle to a DLL/shared object
// ----------------------------------------------------------------------------
class WXDLLIMPEXP_BASE wxDynamicLibrary
{
public:
// return a valid handle for the main program itself or NULL if back
// linking is not supported by the current platform (e.g. Win32)
static wxDllType GetProgramHandle();
// return the platform standard DLL extension (with leading dot)
static const wxString& GetDllExt() { return ms_dllext; }
wxDynamicLibrary() : m_handle(0) { }
wxDynamicLibrary(const wxString& libname, int flags = wxDL_DEFAULT)
: m_handle(0)
{
Load(libname, flags);
}
// NOTE: this class is (deliberately) not virtual, do not attempt
// to use it polymorphically.
~wxDynamicLibrary() { Unload(); }
// return true if the library was loaded successfully
bool IsLoaded() const { return m_handle != 0; }
// load the library with the given name (full or not), return true if ok
bool Load(const wxString& libname, int flags = wxDL_DEFAULT);
// raw function for loading dynamic libs: always behaves as if
// wxDL_VERBATIM were specified and doesn't log error message if the
// library couldn't be loaded but simply returns NULL
static wxDllType RawLoad(const wxString& libname, int flags = wxDL_DEFAULT);
// detach the library object from its handle, i.e. prevent the object from
// unloading the library in its dtor -- the caller is now responsible for
// doing this
wxDllType Detach() { wxDllType h = m_handle; m_handle = 0; return h; }
// unload the given library handle (presumably returned by Detach() before)
static void Unload(wxDllType handle);
// unload the library, also done automatically in dtor
void Unload() { if ( IsLoaded() ) { Unload(m_handle); m_handle = 0; } }
// Return the raw handle from dlopen and friends.
wxDllType GetLibHandle() const { return m_handle; }
// check if the given symbol is present in the library, useful to verify if
// a loadable module is our plugin, for example, without provoking error
// messages from GetSymbol()
bool HasSymbol(const wxString& name) const
{
bool ok;
DoGetSymbol(name, &ok);
return ok;
}
// resolve a symbol in a loaded DLL, such as a variable or function name.
// 'name' is the (possibly mangled) name of the symbol. (use extern "C" to
// export unmangled names)
//
// Since it is perfectly valid for the returned symbol to actually be NULL,
// that is not always indication of an error. Pass and test the parameter
// 'success' for a true indication of success or failure to load the
// symbol.
//
// Returns a pointer to the symbol on success, or NULL if an error occurred
// or the symbol wasn't found.
void *GetSymbol(const wxString& name, bool *success = NULL) const;
// low-level version of GetSymbol()
static void *RawGetSymbol(wxDllType handle, const wxString& name);
void *RawGetSymbol(const wxString& name) const
{
#if defined (__WXPM__) || defined(__EMX__)
return GetSymbol(name);
#else
return RawGetSymbol(m_handle, name);
#endif
}
#ifdef __WXMSW__
// this function is useful for loading functions from the standard Windows
// DLLs: such functions have an 'A' (in ANSI build) or 'W' (in Unicode, or
// wide character build) suffix if they take string parameters
static void *RawGetSymbolAorW(wxDllType handle, const wxString& name)
{
return RawGetSymbol
(
handle,
name +
#if wxUSE_UNICODE
L'W'
#else
'A'
#endif
);
}
void *GetSymbolAorW(const wxString& name) const
{
return RawGetSymbolAorW(m_handle, name);
}
#endif // __WXMSW__
// return all modules/shared libraries in the address space of this process
//
// returns an empty array if not implemented or an error occurred
static wxDynamicLibraryDetailsArray ListLoaded();
// return platform-specific name of dynamic library with proper extension
// and prefix (e.g. "foo.dll" on Windows or "libfoo.so" on Linux)
static wxString CanonicalizeName(const wxString& name,
wxDynamicLibraryCategory cat = wxDL_LIBRARY);
// return name of wxWidgets plugin (adds compiler and version info
// to the filename):
static wxString
CanonicalizePluginName(const wxString& name,
wxPluginCategory cat = wxDL_PLUGIN_GUI);
// return plugin directory on platforms where it makes sense and empty
// string on others:
static wxString GetPluginsDirectory();
protected:
// common part of GetSymbol() and HasSymbol()
void *DoGetSymbol(const wxString& name, bool *success = 0) const;
#ifdef wxHAVE_DYNLIB_ERROR
// log the error after a dlxxx() function failure
static void Error();
#endif // wxHAVE_DYNLIB_ERROR
// platform specific shared lib suffix.
static const wxString ms_dllext;
// the handle to DLL or NULL
wxDllType m_handle;
// no copy ctor/assignment operators (or we'd try to unload the library
// twice)
DECLARE_NO_COPY_CLASS(wxDynamicLibrary)
};
// ----------------------------------------------------------------------------
// Interesting defines
// ----------------------------------------------------------------------------
#define WXDLL_ENTRY_FUNCTION() \
extern "C" WXEXPORT const wxClassInfo *wxGetClassFirst(); \
const wxClassInfo *wxGetClassFirst() { \
return wxClassInfo::GetFirst(); \
}
#endif // wxUSE_DYNLIB_CLASS
#endif // _WX_DYNLIB_H__