/* 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;
}