/* Support for dynamic loading of extension modules on Mac OS X

** All references to "NeXT" are for historical reasons.

*/

#include "Python.h"

#include "importdl.h"

#include <mach-o/dyld.h>

const struct filedescr _PyImport_DynLoadFiletab[] = {

	{".so", "rb", C_EXTENSION},

	{"module.so", "rb", C_EXTENSION},

	{0, 0}

};

/*

** Python modules are Mach-O MH_BUNDLE files. The best way to load these

** is each in a private namespace, so you can load, say, a module bar and a

** module foo.bar. If we load everything in the global namespace the two

** initbar() symbols will conflict.

** However, it seems some extension packages depend upon being able to access

** each others' global symbols. There seems to be no way to eat our cake and

** have it, so the USE_DYLD_GLOBAL_NAMESPACE define determines which behaviour

** you get.

*/

#ifdef USE_DYLD_GLOBAL_NAMESPACE

#define LINKOPTIONS NSLINKMODULE_OPTION_BINDNOW|NSLINKMODULE_OPTION_RETURN_ON_ERROR

#else

#define LINKOPTIONS NSLINKMODULE_OPTION_BINDNOW| \

	NSLINKMODULE_OPTION_RETURN_ON_ERROR|NSLINKMODULE_OPTION_PRIVATE

#endif

dl_funcptr _PyImport_GetDynLoadFunc(const char *fqname, const char *shortname,

					const char *pathname, FILE *fp)

{

	dl_funcptr p = NULL;

	char funcname[258];

	NSObjectFileImageReturnCode rc;

	NSObjectFileImage image;

	NSModule newModule;

	NSSymbol theSym;

	const char *errString;

	char errBuf[512];

	PyOS_snprintf(funcname, sizeof(funcname), "_init%.200s", shortname);

#ifdef USE_DYLD_GLOBAL_NAMESPACE

	if (NSIsSymbolNameDefined(funcname)) {

		theSym = NSLookupAndBindSymbol(funcname);

		p = (dl_funcptr)NSAddressOfSymbol(theSym);

		return p;

	}

#endif

	rc = NSCreateObjectFileImageFromFile(pathname, &image);

	switch(rc) {

		default:

		case NSObjectFileImageFailure:

		case NSObjectFileImageFormat:

			/* for these a message is printed on stderr by dyld */

			errString = "Can't create object file image";

		break;

		case NSObjectFileImageSuccess:

			errString = NULL;

			break;

		case NSObjectFileImageInappropriateFile:

			errString = "Inappropriate file type for dynamic loading";

			break;

		case NSObjectFileImageArch:

			errString = "Wrong CPU type in object file";

			break;

		case NSObjectFileImageAccess:

			errString = "Can't read object file (no access)";

			break;

	}

	if (errString == NULL) {

		newModule = NSLinkModule(image, pathname, LINKOPTIONS);

		if (newModule == NULL) {

			int errNo;

			const char *fileName, *moreErrorStr;

			NSLinkEditErrors c;

			NSLinkEditError( &c, &errNo, &fileName, &moreErrorStr );

			PyOS_snprintf(errBuf, 512, "Failure linking new module: %s: %s", 

					fileName, moreErrorStr);

			errString = errBuf;

		}

	}

	if (errString != NULL) {

		PyErr_SetString(PyExc_ImportError, errString);

		return NULL;

	}

#ifdef USE_DYLD_GLOBAL_NAMESPACE

	if (!NSIsSymbolNameDefined(funcname)) {

		/* UnlinkModule() isn't implemented in current versions, but calling it does no harm */

		/* NSUnLinkModule(newModule, FALSE); removed: causes problems for ObjC code */

		PyErr_Format(PyExc_ImportError,

				 "Loaded module does not contain symbol %.200s",

				 funcname);

		return NULL;

	}

	theSym = NSLookupAndBindSymbol(funcname);

#else

	theSym = NSLookupSymbolInModule(newModule, funcname);

	if ( theSym == NULL ) {

		/* NSUnLinkModule(newModule, FALSE); removed: causes problems for ObjC code */

		PyErr_Format(PyExc_ImportError,

				 "Loaded module does not contain symbol %.200s",

				 funcname);

		return NULL;

	}

#endif

	p = (dl_funcptr)NSAddressOfSymbol(theSym);

	return p;

}