Rework the dl* Darwin compatibility code so it uses the real functions when

available.  If compiled to allow for pre-10.3 systems it will do the check
at runtime and the compatibility functions will be compiled but likely
not used.  If compiled with 10.3 or higher as the minimum version, the
compatibility functions will not be compiled and the library will work
identically as it does on all other UNIX.

Even if the compatibility code is compiled in, the function names are now
prefixed with wx_darwin_ and are marked static so they don't make it into
the exported symbols, even in their C++-mangled form.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@51898 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

diff --git a/src/unix/dlunix.cpp b/src/unix/dlunix.cpp
index 2c9fec3b3ca8dcd3737021454043de9776e18c67..4e2d7553dcc27fb64f191c6b946abc03afada10e 100644 (file)
--- a/src/unix/dlunix.cpp
+++ b/src/unix/dlunix.cpp
@@ -33,12 +33,14 @@
     #include "wx/log.h"
 #endif
 
-// only Mac OS X 10.3+ has dlfcn.h, and it is simpler to always provide our own
-// wrappers using the native functions instead of doing checks for OS version
-#ifndef __DARWIN__
+#ifdef HAVE_DLOPEN
     #include <dlfcn.h>
 #endif
 
+#ifdef __DARWIN__
+    #include <AvailabilityMacros.h>
+#endif
+
 // if some flags are not supported, just ignore them
 #ifndef RTLD_LAZY
     #define RTLD_LAZY 0
@@ -78,9 +80,10 @@
 
 // ----------------------------------------------------------------------------
 // dlxxx() emulation for Darwin
+// Only useful if the OS X version could be < 10.3 at runtime
 // ----------------------------------------------------------------------------
 
-#if defined(__DARWIN__)
+#if defined(__DARWIN__) && (MAC_OS_X_VERSION_MIN_REQUIRED < MAC_OS_X_VERSION_10_3)
 // ---------------------------------------------------------------------------
 // For Darwin/Mac OS X
 //   supply the sun style dlopen functions in terms of Darwin NS*
@@ -98,12 +101,12 @@
 
 static char dl_last_error[1024];
 
-const char *dlerror()
+static const char *wx_darwin_dlerror()
 {
     return dl_last_error;
 }
 
-void *dlopen(const char *path, int WXUNUSED(mode) /* mode is ignored */)
+static void *wx_darwin_dlopen(const char *path, int WXUNUSED(mode) /* mode is ignored */)
 {
     NSObjectFileImage ofile;
     NSModule handle = NULL;
@@ -159,13 +162,13 @@ void *dlopen(const char *path, int WXUNUSED(mode) /* mode is ignored */)
     return handle;
 }
 
-int dlclose(void *handle)
+static int wx_darwin_dlclose(void *handle)
 {
     NSUnLinkModule((NSModule)handle, NSUNLINKMODULE_OPTION_NONE);
     return 0;
 }
 
-void *dlsym(void *handle, const char *symbol)
+static void *wx_darwin_dlsym(void *handle, const char *symbol)
 {
     // as on many other systems, C symbols have prepended underscores under
     // Darwin but unlike the normal dlopen(), NSLookupSymbolInModule() is not
@@ -179,6 +182,61 @@ void *dlsym(void *handle, const char *symbol)
     return nsSymbol ? NSAddressOfSymbol(nsSymbol) : NULL;
 }
 
+// Add the weak linking attribute to dlopen's declaration
+extern void * dlopen(const char * __path, int __mode) AVAILABLE_MAC_OS_X_VERSION_10_3_AND_LATER;
+
+// For all of these methods we test dlopen since all of the dl functions we use were added
+// to OS X at the same time.  This also ensures we don't dlopen with the real function then
+// dlclose with the internal implementation.
+
+static inline void *wx_dlopen(const char *__path, int __mode)
+{
+#ifdef HAVE_DLOPEN
+    if(&dlopen != NULL)
+        return dlopen(__path, __mode);
+    else
+#endif
+        return wx_darwin_dlopen(__path, __mode);
+}
+
+static inline int wx_dlclose(void *__handle)
+{
+#ifdef HAVE_DLOPEN
+    if(&dlopen != NULL)
+        return dlclose(__handle);
+    else
+#endif
+        return wx_darwin_dlclose(__handle);
+}
+
+static inline const char *wx_dlerror()
+{
+#ifdef HAVE_DLOPEN
+    if(&dlopen != NULL)
+        return dlerror();
+    else
+#endif
+        return wx_darwin_dlerror();
+}
+
+static inline void *wx_dlsym(void *__handle, const char *__symbol)
+{
+#ifdef HAVE_DLOPEN
+    if(&dlopen != NULL)
+        return dlsym(__handle, __symbol);
+    else
+#endif
+        return wx_darwin_dlsym(__handle, __symbol);
+}
+
+#else // __DARWIN__/!__DARWIN__
+
+// Use preprocessor definitions for non-Darwin or OS X >= 10.3
+#define wx_dlopen(__path,__mode) dlopen(__path,__mode)
+#define wx_dlclose(__handle) dlclose(__handle)
+#define wx_dlerror() dlerror()
+#define wx_dlsym(__handle,__symbol) dlsym(__handle,__symbol)
+
 #endif // defined(__DARWIN__)
 
 // ----------------------------------------------------------------------------
@@ -188,7 +246,7 @@ void *dlsym(void *handle, const char *symbol)
 wxDllType wxDynamicLibrary::GetProgramHandle()
 {
 #ifdef USE_POSIX_DL_FUNCS
-   return dlopen(0, RTLD_LAZY);
+   return wx_dlopen(0, RTLD_LAZY);
 #else
    return PROG_HANDLE;
 #endif
@@ -209,7 +267,7 @@ wxDllType wxDynamicLibrary::RawLoad(const wxString& libname, int flags)
     if ( flags & wxDL_GLOBAL )
         rtldFlags |= RTLD_GLOBAL;
 
-    return dlopen(libname.fn_str(), rtldFlags);
+    return wx_dlopen(libname.fn_str(), rtldFlags);
 #else // !USE_POSIX_DL_FUNCS
     int shlFlags = 0;
 
@@ -234,7 +292,7 @@ void wxDynamicLibrary::Unload(wxDllType handle)
 #endif
 
 #ifdef USE_POSIX_DL_FUNCS
-    dlclose(handle);
+    wx_dlclose(handle);
 #else // !USE_POSIX_DL_FUNCS
     shl_unload(handle);
 #endif // USE_POSIX_DL_FUNCS/!USE_POSIX_DL_FUNCS
@@ -251,7 +309,7 @@ void *wxDynamicLibrary::RawGetSymbol(wxDllType handle, const wxString& name)
     void *symbol;
 
 #ifdef USE_POSIX_DL_FUNCS
-    symbol = dlsym(handle, name.fn_str());
+    symbol = wx_dlsym(handle, name.fn_str());
 #else // !USE_POSIX_DL_FUNCS
     // note that shl_findsym modifies the handle argument to indicate where the
     // symbol was found, but it's ok to modify the local handle copy here
@@ -271,7 +329,7 @@ void *wxDynamicLibrary::RawGetSymbol(wxDllType handle, const wxString& name)
 /* static */
 void wxDynamicLibrary::Error()
 {
-    wxString err(dlerror());
+    wxString err(wx_dlerror());
 
     if ( err.empty() )
         err = _("Unknown dynamic library error");