/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#include "libuutil_common.h"

#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/avl.h>

static uu_avl_pool_t    uu_null_apool = { &uu_null_apool, &uu_null_apool };
static pthread_mutex_t  uu_apool_list_lock = PTHREAD_MUTEX_INITIALIZER;

/*
 * The index mark change on every insert and delete, to catch stale
 * references.
 *
 * We leave the low bit alone, since the avl code uses it.
 */
#define INDEX_MAX               (sizeof (uintptr_t) - 2)
#define INDEX_NEXT(m)           (((m) == INDEX_MAX)? 2 : ((m) + 2) & INDEX_MAX)

#define INDEX_DECODE(i)         ((i) & ~INDEX_MAX)
#define INDEX_ENCODE(p, n)      (((n) & ~INDEX_MAX) | (p)->ua_index)
#define INDEX_VALID(p, i)       (((i) & INDEX_MAX) == (p)->ua_index)
#define INDEX_CHECK(i)          (((i) & INDEX_MAX) != 0)

/*
 * When an element is inactive (not in a tree), we keep a marked pointer to
 * its containing pool in its first word, and a NULL pointer in its second.
 *
 * On insert, we use these to verify that it comes from the correct pool.
 */
#define NODE_ARRAY(p, n)        ((uintptr_t *)((uintptr_t)(n) + \
                                    (pp)->uap_nodeoffset))

#define POOL_TO_MARKER(pp) (((uintptr_t)(pp) | 1))

#define DEAD_MARKER             0xc4

uu_avl_pool_t *
uu_avl_pool_create(const char *name, size_t objsize, size_t nodeoffset,
    uu_compare_fn_t *compare_func, uint32_t flags)
{
        uu_avl_pool_t *pp, *next, *prev;

        if (name == NULL ||
            uu_check_name(name, UU_NAME_DOMAIN) == -1 ||
            nodeoffset + sizeof (uu_avl_node_t) > objsize ||
            compare_func == NULL) {
                uu_set_error(UU_ERROR_INVALID_ARGUMENT);
                return (NULL);
        }

        if (flags & ~UU_AVL_POOL_DEBUG) {
                uu_set_error(UU_ERROR_UNKNOWN_FLAG);
                return (NULL);
        }

        pp = uu_zalloc(sizeof (uu_avl_pool_t));
        if (pp == NULL) {
                uu_set_error(UU_ERROR_NO_MEMORY);
                return (NULL);
        }

        (void) strlcpy(pp->uap_name, name, sizeof (pp->uap_name));
        pp->uap_nodeoffset = nodeoffset;
        pp->uap_objsize = objsize;
        pp->uap_cmp = compare_func;
        if (flags & UU_AVL_POOL_DEBUG)
                pp->uap_debug = 1;
        pp->uap_last_index = 0;

        (void) pthread_mutex_init(&pp->uap_lock, NULL);

        pp->uap_null_avl.ua_next_enc = UU_PTR_ENCODE(&pp->uap_null_avl);
        pp->uap_null_avl.ua_prev_enc = UU_PTR_ENCODE(&pp->uap_null_avl);

        (void) pthread_mutex_lock(&uu_apool_list_lock);
        pp->uap_next = next = &uu_null_apool;
        pp->uap_prev = prev = next->uap_prev;
        next->uap_prev = pp;
        prev->uap_next = pp;
        (void) pthread_mutex_unlock(&uu_apool_list_lock);

        return (pp);
}

void
uu_avl_pool_destroy(uu_avl_pool_t *pp)
{
        if (pp->uap_debug) {
                if (pp->uap_null_avl.ua_next_enc !=
                    UU_PTR_ENCODE(&pp->uap_null_avl) ||
                    pp->uap_null_avl.ua_prev_enc !=
                    UU_PTR_ENCODE(&pp->uap_null_avl)) {
                        uu_panic("uu_avl_pool_destroy: Pool \"%.*s\" (%p) has "
                            "outstanding avls, or is corrupt.\n",
                            (int)sizeof (pp->uap_name), pp->uap_name,
                            (void *)pp);
                }
        }
        (void) pthread_mutex_lock(&uu_apool_list_lock);
        pp->uap_next->uap_prev = pp->uap_prev;
        pp->uap_prev->uap_next = pp->uap_next;
        (void) pthread_mutex_unlock(&uu_apool_list_lock);
        (void) pthread_mutex_destroy(&pp->uap_lock);
        pp->uap_prev = NULL;
        pp->uap_next = NULL;
        uu_free(pp);
}

void
uu_avl_node_init(void *base, uu_avl_node_t *np, uu_avl_pool_t *pp)
{
        uintptr_t *na = (uintptr_t *)np;

        if (pp->uap_debug) {
                uintptr_t offset = (uintptr_t)np - (uintptr_t)base;
                if (offset + sizeof (*np) > pp->uap_objsize) {
                        uu_panic("uu_avl_node_init(%p, %p, %p (\"%s\")): "
                            "offset %ld doesn't fit in object (size %ld)\n",
                            base, (void *)np, (void *)pp, pp->uap_name,
                            (long)offset, (long)pp->uap_objsize);
                }
                if (offset != pp->uap_nodeoffset) {
                        uu_panic("uu_avl_node_init(%p, %p, %p (\"%s\")): "
                            "offset %ld doesn't match pool's offset (%ld)\n",
                            base, (void *)np, (void *)pp, pp->uap_name,
                            (long)offset, (long)pp->uap_objsize);
                }
        }

        na[0] = POOL_TO_MARKER(pp);
        na[1] = 0;
}

void
uu_avl_node_fini(void *base, uu_avl_node_t *np, uu_avl_pool_t *pp)
{
        uintptr_t *na = (uintptr_t *)np;

        if (pp->uap_debug) {
                if (na[0] == DEAD_MARKER && na[1] == DEAD_MARKER) {
                        uu_panic("uu_avl_node_fini(%p, %p, %p (\"%s\")): "
                            "node already finied\n",
                            base, (void *)np, (void *)pp, pp->uap_name);
                }
                if (na[0] != POOL_TO_MARKER(pp) || na[1] != 0) {
                        uu_panic("uu_avl_node_fini(%p, %p, %p (\"%s\")): "
                            "node corrupt, in tree, or in different pool\n",
                            base, (void *)np, (void *)pp, pp->uap_name);
                }
        }

        na[0] = DEAD_MARKER;
        na[1] = DEAD_MARKER;
        na[2] = DEAD_MARKER;
}

struct uu_avl_node_compare_info {
        uu_compare_fn_t *ac_compare;
        void            *ac_private;
        void            *ac_right;
        void            *ac_found;
};

static int
uu_avl_node_compare(const void *l, const void *r)
{
        struct uu_avl_node_compare_info *info =
            (struct uu_avl_node_compare_info *)l;

        int res = info->ac_compare(r, info->ac_right, info->ac_private);

        if (res == 0) {
                if (info->ac_found == NULL)
                        info->ac_found = (void *)r;
                return (-1);
        }
        if (res < 0)
                return (1);
        return (-1);
}

uu_avl_t *
uu_avl_create(uu_avl_pool_t *pp, void *parent, uint32_t flags)
{
        uu_avl_t *ap, *next, *prev;

        if (flags & ~UU_AVL_DEBUG) {
                uu_set_error(UU_ERROR_UNKNOWN_FLAG);
                return (NULL);
        }

        ap = uu_zalloc(sizeof (*ap));
        if (ap == NULL) {
                uu_set_error(UU_ERROR_NO_MEMORY);
                return (NULL);
        }

        ap->ua_pool = pp;
        ap->ua_parent_enc = UU_PTR_ENCODE(parent);
        ap->ua_debug = pp->uap_debug || (flags & UU_AVL_DEBUG);
        ap->ua_index = (pp->uap_last_index = INDEX_NEXT(pp->uap_last_index));

        avl_create(&ap->ua_tree, &uu_avl_node_compare, pp->uap_objsize,
            pp->uap_nodeoffset);

        ap->ua_null_walk.uaw_next = &ap->ua_null_walk;
        ap->ua_null_walk.uaw_prev = &ap->ua_null_walk;

        (void) pthread_mutex_lock(&pp->uap_lock);
        next = &pp->uap_null_avl;
        prev = UU_PTR_DECODE(next->ua_prev_enc);
        ap->ua_next_enc = UU_PTR_ENCODE(next);
        ap->ua_prev_enc = UU_PTR_ENCODE(prev);
        next->ua_prev_enc = UU_PTR_ENCODE(ap);
        prev->ua_next_enc = UU_PTR_ENCODE(ap);
        (void) pthread_mutex_unlock(&pp->uap_lock);

        return (ap);
}

void
uu_avl_destroy(uu_avl_t *ap)
{
        uu_avl_pool_t *pp = ap->ua_pool;

        if (ap->ua_debug) {
                if (avl_numnodes(&ap->ua_tree) != 0) {
                        uu_panic("uu_avl_destroy(%p): tree not empty\n",
                            (void *)ap);
                }
                if (ap->ua_null_walk.uaw_next != &ap->ua_null_walk ||
                    ap->ua_null_walk.uaw_prev != &ap->ua_null_walk) {
                        uu_panic("uu_avl_destroy(%p):  outstanding walkers\n",
                            (void *)ap);
                }
        }
        (void) pthread_mutex_lock(&pp->uap_lock);
        UU_AVL_PTR(ap->ua_next_enc)->ua_prev_enc = ap->ua_prev_enc;
        UU_AVL_PTR(ap->ua_prev_enc)->ua_next_enc = ap->ua_next_enc;
        (void) pthread_mutex_unlock(&pp->uap_lock);
        ap->ua_prev_enc = UU_PTR_ENCODE(NULL);
        ap->ua_next_enc = UU_PTR_ENCODE(NULL);

        ap->ua_pool = NULL;
        avl_destroy(&ap->ua_tree);

        uu_free(ap);
}

size_t
uu_avl_numnodes(uu_avl_t *ap)
{
        return (avl_numnodes(&ap->ua_tree));
}

void *
uu_avl_first(uu_avl_t *ap)
{
        return (avl_first(&ap->ua_tree));
}

void *
uu_avl_last(uu_avl_t *ap)
{
        return (avl_last(&ap->ua_tree));
}

void *
uu_avl_next(uu_avl_t *ap, void *node)
{
        return (AVL_NEXT(&ap->ua_tree, node));
}

void *
uu_avl_prev(uu_avl_t *ap, void *node)
{
        return (AVL_PREV(&ap->ua_tree, node));
}

static void
_avl_walk_init(uu_avl_walk_t *wp, uu_avl_t *ap, uint32_t flags)
{
        uu_avl_walk_t *next, *prev;

        int robust = (flags & UU_WALK_ROBUST);
        int direction = (flags & UU_WALK_REVERSE)? -1 : 1;

        (void) memset(wp, 0, sizeof (*wp));
        wp->uaw_avl = ap;
        wp->uaw_robust = robust;
        wp->uaw_dir = direction;

        if (direction > 0)
                wp->uaw_next_result = avl_first(&ap->ua_tree);
        else
                wp->uaw_next_result = avl_last(&ap->ua_tree);

        if (ap->ua_debug || robust) {
                wp->uaw_next = next = &ap->ua_null_walk;
                wp->uaw_prev = prev = next->uaw_prev;
                next->uaw_prev = wp;
                prev->uaw_next = wp;
        }
}

static void *
_avl_walk_advance(uu_avl_walk_t *wp, uu_avl_t *ap)
{
        void *np = wp->uaw_next_result;

        avl_tree_t *t = &ap->ua_tree;

        if (np == NULL)
                return (NULL);

        wp->uaw_next_result = (wp->uaw_dir > 0)? AVL_NEXT(t, np) :
            AVL_PREV(t, np);

        return (np);
}

static void
_avl_walk_fini(uu_avl_walk_t *wp)
{
        if (wp->uaw_next != NULL) {
                wp->uaw_next->uaw_prev = wp->uaw_prev;
                wp->uaw_prev->uaw_next = wp->uaw_next;
                wp->uaw_next = NULL;
                wp->uaw_prev = NULL;
        }
        wp->uaw_avl = NULL;
        wp->uaw_next_result = NULL;
}

uu_avl_walk_t *
uu_avl_walk_start(uu_avl_t *ap, uint32_t flags)
{
        uu_avl_walk_t *wp;

        if (flags & ~(UU_WALK_ROBUST | UU_WALK_REVERSE)) {
                uu_set_error(UU_ERROR_UNKNOWN_FLAG);
                return (NULL);
        }

        wp = uu_zalloc(sizeof (*wp));
        if (wp == NULL) {
                uu_set_error(UU_ERROR_NO_MEMORY);
                return (NULL);
        }

        _avl_walk_init(wp, ap, flags);
        return (wp);
}

void *
uu_avl_walk_next(uu_avl_walk_t *wp)
{
        return (_avl_walk_advance(wp, wp->uaw_avl));
}

void
uu_avl_walk_end(uu_avl_walk_t *wp)
{
        _avl_walk_fini(wp);
        uu_free(wp);
}

int
uu_avl_walk(uu_avl_t *ap, uu_walk_fn_t *func, void *private, uint32_t flags)
{
        void *e;
        uu_avl_walk_t my_walk;

        int status = UU_WALK_NEXT;

        if (flags & ~(UU_WALK_ROBUST | UU_WALK_REVERSE)) {
                uu_set_error(UU_ERROR_UNKNOWN_FLAG);
                return (-1);
        }

        _avl_walk_init(&my_walk, ap, flags);
        while (status == UU_WALK_NEXT &&
            (e = _avl_walk_advance(&my_walk, ap)) != NULL)
                status = (*func)(e, private);
        _avl_walk_fini(&my_walk);

        if (status >= 0)
                return (0);
        uu_set_error(UU_ERROR_CALLBACK_FAILED);
        return (-1);
}

void
uu_avl_remove(uu_avl_t *ap, void *elem)
{
        uu_avl_walk_t *wp;
        uu_avl_pool_t *pp = ap->ua_pool;
        uintptr_t *na = NODE_ARRAY(pp, elem);

        if (ap->ua_debug) {
                /*
                 * invalidate outstanding uu_avl_index_ts.
                 */
                ap->ua_index = INDEX_NEXT(ap->ua_index);
        }

        /*
         * Robust walkers most be advanced, if we are removing the node
         * they are currently using.  In debug mode, non-robust walkers
         * are also on the walker list.
         */
        for (wp = ap->ua_null_walk.uaw_next; wp != &ap->ua_null_walk;
            wp = wp->uaw_next) {
                if (wp->uaw_robust) {
                        if (elem == wp->uaw_next_result)
                                (void) _avl_walk_advance(wp, ap);
                } else if (wp->uaw_next_result != NULL) {
                        uu_panic("uu_avl_remove(%p, %p): active non-robust "
                            "walker\n", (void *)ap, elem);
                }
        }

        avl_remove(&ap->ua_tree, elem);

        na[0] = POOL_TO_MARKER(pp);
        na[1] = 0;
}

void *
uu_avl_teardown(uu_avl_t *ap, void **cookie)
{
        void *elem = avl_destroy_nodes(&ap->ua_tree, cookie);

        if (elem != NULL) {
                uu_avl_pool_t *pp = ap->ua_pool;
                uintptr_t *na = NODE_ARRAY(pp, elem);

                na[0] = POOL_TO_MARKER(pp);
                na[1] = 0;
        }
        return (elem);
}

void *
uu_avl_find(uu_avl_t *ap, void *elem, void *private, uu_avl_index_t *out)
{
        struct uu_avl_node_compare_info info;
        void *result;

        info.ac_compare = ap->ua_pool->uap_cmp;
        info.ac_private = private;
        info.ac_right = elem;
        info.ac_found = NULL;

        result = avl_find(&ap->ua_tree, &info, out);
        if (out != NULL)
                *out = INDEX_ENCODE(ap, *out);

        if (ap->ua_debug && result != NULL)
                uu_panic("uu_avl_find: internal error: avl_find succeeded\n");

        return (info.ac_found);
}

void
uu_avl_insert(uu_avl_t *ap, void *elem, uu_avl_index_t idx)
{
        if (ap->ua_debug) {
                uu_avl_pool_t *pp = ap->ua_pool;
                uintptr_t *na = NODE_ARRAY(pp, elem);

                if (na[1] != 0)
                        uu_panic("uu_avl_insert(%p, %p, %p): node already "
                            "in tree, or corrupt\n",
                            (void *)ap, elem, (void *)idx);
                if (na[0] == 0)
                        uu_panic("uu_avl_insert(%p, %p, %p): node not "
                            "initialized\n",
                            (void *)ap, elem, (void *)idx);
                if (na[0] != POOL_TO_MARKER(pp))
                        uu_panic("uu_avl_insert(%p, %p, %p): node from "
                            "other pool, or corrupt\n",
                            (void *)ap, elem, (void *)idx);

                if (!INDEX_VALID(ap, idx))
                        uu_panic("uu_avl_insert(%p, %p, %p): %s\n",
                            (void *)ap, elem, (void *)idx,
                            INDEX_CHECK(idx)? "outdated index" :
                            "invalid index");

                /*
                 * invalidate outstanding uu_avl_index_ts.
                 */
                ap->ua_index = INDEX_NEXT(ap->ua_index);
        }
        avl_insert(&ap->ua_tree, elem, INDEX_DECODE(idx));
}

void *
uu_avl_nearest_next(uu_avl_t *ap, uu_avl_index_t idx)
{
        if (ap->ua_debug && !INDEX_VALID(ap, idx))
                uu_panic("uu_avl_nearest_next(%p, %p): %s\n",
                    (void *)ap, (void *)idx, INDEX_CHECK(idx)?
                    "outdated index" : "invalid index");
        return (avl_nearest(&ap->ua_tree, INDEX_DECODE(idx), AVL_AFTER));
}

void *
uu_avl_nearest_prev(uu_avl_t *ap, uu_avl_index_t idx)
{
        if (ap->ua_debug && !INDEX_VALID(ap, idx))
                uu_panic("uu_avl_nearest_prev(%p, %p): %s\n",
                    (void *)ap, (void *)idx, INDEX_CHECK(idx)?
                    "outdated index" : "invalid index");
        return (avl_nearest(&ap->ua_tree, INDEX_DECODE(idx), AVL_BEFORE));
}

/*
 * called from uu_lockup() and uu_release(), as part of our fork1()-safety.
 */
void
uu_avl_lockup(void)
{
        uu_avl_pool_t *pp;

        (void) pthread_mutex_lock(&uu_apool_list_lock);
        for (pp = uu_null_apool.uap_next; pp != &uu_null_apool;
            pp = pp->uap_next)
                (void) pthread_mutex_lock(&pp->uap_lock);
}

void
uu_avl_release(void)
{
        uu_avl_pool_t *pp;

        for (pp = uu_null_apool.uap_next; pp != &uu_null_apool;
            pp = pp->uap_next)
                (void) pthread_mutex_unlock(&pp->uap_lock);
        (void) pthread_mutex_unlock(&uu_apool_list_lock);
}