/* -*- Mode: C; c-basic-offset:4 ; indent-tabs-mode:nil -*- */
/*
 * Copyright (c) 2004-2005 The Trustees of Indiana University and Indiana
 *                         University Research and Technology
 *                         Corporation.  All rights reserved.
 * Copyright (c) 2004-2005 The University of Tennessee and The University
 *                         of Tennessee Research Foundation.  All rights
 *                         reserved.
 * Copyright (c) 2004-2007 High Performance Computing Center Stuttgart,
 *                         University of Stuttgart.  All rights reserved.
 * Copyright (c) 2004-2005 The Regents of the University of California.
 *                         All rights reserved.
 * Copyright (c) 2015      Los Alamos National Security, LLC. All rights
 *                         reserved.
 * $COPYRIGHT$
 *
 * Additional copyrights may follow
 *
 * $HEADER$
 */

/**
 * @file
 *
 * Implementation of opal_object_t, the base opal foundation class
 */

#include "opal_config.h"

#include <stdio.h>

#include "opal/class/opal_object.h"
#include "opal/constants.h"
#include "opal/sys/atomic.h"

/*
 * Instantiation of class descriptor for the base class.  This is
 * special, since be mark it as already initialized, with no parent
 * and no constructor or destructor.
 */
opal_class_t opal_object_t_class = {
    "opal_object_t",      /* name */
    NULL,                 /* parent class */
    NULL,                 /* constructor */
    NULL,                 /* destructor */
    1,                    /* initialized  -- this class is preinitialized */
    0,                    /* class hierarchy depth */
    NULL,                 /* array of constructors */
    NULL,                 /* array of destructors */
    sizeof(opal_object_t) /* size of the opal object */
};

int opal_class_init_epoch = 1;

/*
 * Local variables
 */
static opal_atomic_lock_t class_lock = OPAL_ATOMIC_LOCK_INIT;
static void **classes = NULL;
static int num_classes = 0;
static int max_classes = 0;
static const int increment = 10;

/*
 * Local functions
 */
static void save_class(opal_class_t *cls);
static void expand_array(void);

/*
 * Lazy initialization of class descriptor.
 */
void opal_class_initialize(opal_class_t *cls)
{
    opal_class_t *c;
    opal_construct_t *cls_construct_array;
    opal_destruct_t *cls_destruct_array;
    int cls_construct_array_count;
    int cls_destruct_array_count;
    int i;

    assert(cls);

    /* Check to see if any other thread got in here and initialized
       this class before we got a chance to */

    if (opal_class_init_epoch == cls->cls_initialized) {
        return;
    }
    opal_atomic_lock(&class_lock);

    /* If another thread initializing this same class came in at
       roughly the same time, it may have gotten the lock and
       initialized.  So check again. */

    if (opal_class_init_epoch == cls->cls_initialized) {
        opal_atomic_unlock(&class_lock);
        return;
    }

    /*
     * First calculate depth of class hierarchy
     * And the number of constructors and destructors
     */

    cls->cls_depth = 0;
    cls_construct_array_count = 0;
    cls_destruct_array_count = 0;
    for (c = cls; c; c = c->cls_parent) {
        if (NULL != c->cls_construct) {
            cls_construct_array_count++;
        }
        if (NULL != c->cls_destruct) {
            cls_destruct_array_count++;
        }
        cls->cls_depth++;
    }

    /*
     * Allocate arrays for hierarchy of constructors and destructors
     * plus for each a NULL-sentinel
     */

    cls->cls_construct_array = (void (**)(opal_object_t *)) malloc(
        (cls_construct_array_count + cls_destruct_array_count + 2) * sizeof(opal_construct_t));
    if (NULL == cls->cls_construct_array) {
        perror("Out of memory");
        exit(-1);
    }
    cls->cls_destruct_array = cls->cls_construct_array + cls_construct_array_count + 1;

    /*
     * The constructor array is reversed, so start at the end
     */

    cls_construct_array = cls->cls_construct_array + cls_construct_array_count;
    cls_destruct_array = cls->cls_destruct_array;

    c = cls;
    *cls_construct_array = NULL; /* end marker for the constructors */
    for (i = 0; i < cls->cls_depth; i++) {
        if (NULL != c->cls_construct) {
            --cls_construct_array;
            *cls_construct_array = c->cls_construct;
        }
        if (NULL != c->cls_destruct) {
            *cls_destruct_array = c->cls_destruct;
            cls_destruct_array++;
        }
        c = c->cls_parent;
    }
    *cls_destruct_array = NULL; /* end marker for the destructors */

    cls->cls_initialized = opal_class_init_epoch;
    save_class(cls);

    /* All done */

    opal_atomic_unlock(&class_lock);
}

/*
 * Note that this is finalize for *all* classes.
 */
int opal_class_finalize(void)
{
    int i;

    if (INT_MAX == opal_class_init_epoch) {
        opal_class_init_epoch = 1;
    } else {
        opal_class_init_epoch++;
    }

    if (NULL != classes) {
        for (i = 0; i < num_classes; ++i) {
            if (NULL != classes[i]) {
                free(classes[i]);
            }
        }
        free(classes);
        classes = NULL;
        num_classes = 0;
        max_classes = 0;
    }

    return OPAL_SUCCESS;
}

static void save_class(opal_class_t *cls)
{
    if (num_classes >= max_classes) {
        expand_array();
    }

    classes[num_classes] = cls->cls_construct_array;
    ++num_classes;
}

static void expand_array(void)
{
    int i;

    max_classes += increment;
    classes = (void **) realloc(classes, sizeof(opal_class_t *) * max_classes);
    if (NULL == classes) {
        perror("class malloc failed");
        exit(-1);
    }
    for (i = num_classes; i < max_classes; ++i) {
        classes[i] = NULL;
    }
}