/* Support for dynamic loading of extension modules */

/* Support for dynamic loading of extension modules */

#include <kernel/image.h>
#include <kernel/OS.h>
#include <stdlib.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 );
}

if( the_id == B_ERROR )
PyOS_snprintf( buff, sizeof(buff),
"BeOS: Failed to load %.200s",
fullpath );
else
PyOS_snprintf( buff, sizeof(buff),
"Unknown error loading %.200s",
fullpath );

PyErr_SetString( PyExc_ImportError, buff );
return NULL;
}

PyOS_snprintf(funcname, sizeof(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:
PyOS_snprintf( buff, sizeof(buff),
"can't load init function for dynamic module: "
"Invalid image ID for %.180s", fullpath );
break;
case B_BAD_INDEX:
PyOS_snprintf( buff, sizeof(buff),
"can't load init function for dynamic module: "
"Bad index for %.180s", funcname );
break;
default:
PyOS_snprintf( buff, sizeof(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;
}