/***********************************************************
Copyright (c) 2000, BeOpen.com.
Copyright (c) 1995-2000, Corporation for National Research Initiatives.
Copyright (c) 1990-1995, Stichting Mathematisch Centrum.
All rights reserved.

See the file "Misc/COPYRIGHT" for information on usage and
redistribution of this file, and for a DISCLAIMER OF ALL WARRANTIES.
******************************************************************/

/* Support for dynamic loading of extension modules */

#include <kernel/image.h>
#include <kernel/OS.h>
#include <stdlib.h>
#include <unistd.h>

#include "Python.h"
#include "importdl.h"

const struct filedescr _PyImport_DynLoadFiletab[] = {
	{".so", "rb", C_EXTENSION},
	{"module.so", "rb", C_EXTENSION},
	{0, 0}
};

#if defined(MAXPATHLEN) && !defined(_SYS_PARAM_H)
#undef MAXPATHLEN
#endif

#ifdef WITH_THREAD
#include "pythread.h"
static PyThread_type_lock beos_dyn_lock;
#endif

static PyObject *beos_dyn_images = NULL;

/* ----------------------------------------------------------------------
 * BeOS dynamic loading support
 *
 * This uses shared libraries, but BeOS has its own way of doing things
 * (much easier than dlfnc.h, from the look of things).  We'll use a
 * Python Dictionary object to store the images_ids so we can be very
 * nice and unload them when we exit.
 *
 * Note that this is thread-safe.  Probably irrelevent, because of losing
 * systems... Python probably disables threads while loading modules.
 * Note the use of "probably"!  Better to be safe than sorry. [chrish]
 *
 * As of 1.5.1 this should also work properly when you've configured
 * Python without thread support; the 1.5 version required it, which wasn't
 * very friendly.  Note that I haven't tested it without threading... why
 * would you want to avoid threads on BeOS? [chrish]
 *
 * As of 1.5.2, the PyImport_BeImageID() function has been removed; Donn
 * tells me it's not necessary anymore because of PyCObject_Import().
 * [chrish]
 */

/* Whack an item; the item is an image_id in disguise, so we'll call
 * unload_add_on() for it.
 */
static void beos_nuke_dyn( PyObject *item )
{
	status_t retval;

	if( item ) {
		image_id id = (image_id)PyInt_AsLong( item );
		
		retval = unload_add_on( id );
	}
}

/* atexit() handler that'll call unload_add_on() for every item in the
 * dictionary.
 */
static void beos_cleanup_dyn( void )
{
	if( beos_dyn_images ) {
		int idx;
		int list_size;
		PyObject *id_list;

#ifdef WITH_THREAD
		PyThread_acquire_lock( beos_dyn_lock, 1 );
#endif

		id_list = PyDict_Values( beos_dyn_images );

		list_size = PyList_Size( id_list );
		for( idx = 0; idx < list_size; idx++ ) {
			PyObject *the_item;
			
			the_item = PyList_GetItem( id_list, idx );
			beos_nuke_dyn( the_item );
		}

		PyDict_Clear( beos_dyn_images );

#ifdef WITH_THREAD
		PyThread_free_lock( beos_dyn_lock );
#endif
	}
}

/*
 * Initialize our dictionary, and the dictionary mutex.
 */
static void beos_init_dyn( void )
{
	/* We're protected from a race condition here by the atomic init_count
	 * variable.
	 */
	static int32 init_count = 0;
	int32 val;

	val = atomic_add( &init_count, 1 );
	if( beos_dyn_images == NULL && val == 0 ) {
		beos_dyn_images = PyDict_New();
#ifdef WITH_THREAD
		beos_dyn_lock = PyThread_allocate_lock();
#endif
		atexit( beos_cleanup_dyn );
	}
}

/*
 * Add an image_id to the dictionary; the module name of the loaded image
 * is the key.  Note that if the key is already in the dict, we unload
 * that image; this should allow reload() to work on dynamically loaded
 * modules (super-keen!).
 */
static void beos_add_dyn( char *name, image_id id )
{
	int retval;
	PyObject *py_id;

	if( beos_dyn_images == NULL ) {
		beos_init_dyn();
	}

#ifdef WITH_THREAD
	retval = PyThread_acquire_lock( beos_dyn_lock, 1 );
#endif

	/* If there's already an object with this key in the dictionary,
	 * we're doing a reload(), so let's nuke it.
	 */
	py_id = PyDict_GetItemString( beos_dyn_images, name );
	if( py_id ) {
		beos_nuke_dyn( py_id );
		retval = PyDict_DelItemString( beos_dyn_images, name );
	}

	py_id = PyInt_FromLong( (long)id );
	if( py_id ) {
		retval = PyDict_SetItemString( beos_dyn_images, name, py_id );
	}

#ifdef WITH_THREAD
	PyThread_release_lock( beos_dyn_lock );
#endif
}


dl_funcptr _PyImport_GetDynLoadFunc(const char *fqname, const char *shortname,
				    const char *pathname, FILE *fp)
{
	dl_funcptr p;
	image_id the_id;
	status_t retval;
	char fullpath[PATH_MAX];
	char funcname[258];

	if( Py_VerboseFlag ) {
		printf( "load_add_on( %s )\n", pathname );
	}

	/* Hmm, this old bug appears to have regenerated itself; if the
	 * path isn't absolute, load_add_on() will fail.  Reported to Be
	 * April 21, 1998.
	 */
	if( pathname[0] != '/' ) {
		(void)getcwd( fullpath, PATH_MAX );
		(void)strncat( fullpath, "/", PATH_MAX );
		(void)strncat( fullpath, pathname, PATH_MAX );
			
		if( Py_VerboseFlag ) {
			printf( "load_add_on( %s )\n", fullpath );
		}
	} else {
		(void)strcpy( fullpath, pathname );
	}

	the_id = load_add_on( fullpath );
	if( the_id < B_NO_ERROR ) {
		/* It's too bad load_add_on() doesn't set errno or something...
		 */
		char buff[256];  /* hate hard-coded string sizes... */

		if( Py_VerboseFlag ) {
			printf( "load_add_on( %s ) failed", fullpath );
		}

		switch( the_id ) {
		case B_ERROR:
			sprintf( buff, "BeOS: Failed to load %.200s", fullpath );
			break;
		default:
			sprintf( buff, "Unknown error loading %.200s", fullpath );
			break;
		}

		PyErr_SetString( PyExc_ImportError, buff );
		return NULL;
	}

	sprintf(funcname, "init%.200s", shortname);
	if( Py_VerboseFlag ) {
		printf( "get_image_symbol( %s )\n", funcname );
	}

	retval = get_image_symbol( the_id, funcname, B_SYMBOL_TYPE_TEXT, &p );
	if( retval != B_NO_ERROR || p == NULL ) {
		/* That's bad, we can't find that symbol in the module...
		 */
		char buff[256];  /* hate hard-coded string sizes... */

		if( Py_VerboseFlag ) {
			printf( "get_image_symbol( %s ) failed", funcname );
		}

		switch( retval ) {
		case B_BAD_IMAGE_ID:
			sprintf( buff, "can't load init function for dynamic module: "
			               "Invalid image ID for %.180s", fullpath );
			break;
		case B_BAD_INDEX:
			sprintf( buff, "can't load init function for dynamic module: "
			               "Bad index for %.180s", funcname );
			break;
		default:
			sprintf( buff, "can't load init function for dynamic module: "
			               "Unknown error looking up %.180s", funcname );
			break;
		}

		retval = unload_add_on( the_id );

		PyErr_SetString( PyExc_ImportError, buff );
		return NULL;
	}

	/* Save the module name and image ID for later so we can clean up
	 * gracefully.
	 */
	beos_add_dyn( fqname, the_id );

	return p;
}