astobj2_hash.c

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/*
 * astobj2_hash - Hash table implementation for astobj2.
 *
 * Copyright (C) 2006 Marta Carbone, Luigi Rizzo - Univ. di Pisa, Italy
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */
 
/*! \file
 *
 * \brief Hash table functions implementing astobj2 containers.
 *
 * \author Richard Mudgett <rmudgett@digium.com>
 */
 
#include "asterisk.h"
 
#include "asterisk/_private.h"
#include "asterisk/astobj2.h"
#include "astobj2_private.h"
#include "astobj2_container_private.h"
#include "asterisk/dlinkedlists.h"
#include "asterisk/utils.h"
 
/*!
 * A structure to create a linked list of entries,
 * used within a bucket.
 */
struct hash_bucket_node {
    /*!
     * \brief Items common to all container nodes.
     * \note Must be first in the specific node struct.
     */
    struct ao2_container_node common;
    /*! Next node links in the list. */
    AST_DLLIST_ENTRY(hash_bucket_node) links;
    /*! Hash bucket holding the node. */
    int my_bucket;
};
 
struct hash_bucket {
    /*! List of objects held in the bucket. */
    AST_DLLIST_HEAD_NOLOCK(, hash_bucket_node) list;
#if defined(AO2_DEBUG)
    /*! Number of elements currently in the bucket. */
    int elements;
    /*! Maximum number of elements in the bucket. */
    int max_elements;
#endif  /* defined(AO2_DEBUG) */
};
 
/*!
 * A hash container in addition to values common to all
 * container types, stores the hash callback function, the
 * number of hash buckets, and the hash bucket heads.
 */
struct ao2_container_hash {
    /*!
     * \brief Items common to all containers.
     * \note Must be first in the specific container struct.
     */
    struct ao2_container common;
    ao2_hash_fn *hash_fn;
    /*! Number of hash buckets in this container. */
    int n_buckets;
    /*! Hash bucket array of n_buckets.  Variable size. */
    struct hash_bucket buckets[0];
};
 
/*! Traversal state to restart a hash container traversal. */
struct hash_traversal_state {
    /*! Active sort function in the traversal if not NULL. */
    ao2_sort_fn *sort_fn;
    /*! Saved comparison callback arg pointer. */
    void *arg;
    /*! Starting hash bucket */
    int bucket_start;
    /*! Stopping hash bucket */
    int bucket_last;
    /*! Saved search flags to control traversing the container. */
    enum search_flags flags;
    /*! TRUE if it is a descending search */
    unsigned int descending:1;
};
 
struct hash_traversal_state_check {
    /*
     * If we have a division by zero compile error here then there
     * is not enough room for the state.  Increase AO2_TRAVERSAL_STATE_SIZE.
     */
    char check[1 / (AO2_TRAVERSAL_STATE_SIZE / sizeof(struct hash_traversal_state))];
};
 
/*!
 * \internal
 * \brief Create an empty copy of this container.
 * \since 14.0.0
 *
 * \param self Container to operate upon.
 * \param tag used for debugging.
 * \param file Debug file name invoked from
 * \param line Debug line invoked from
 * \param func Debug function name invoked from
 *
 * \return empty-clone-container on success.
 * \retval NULL on error.
 */
static struct ao2_container *hash_ao2_alloc_empty_clone(struct ao2_container_hash *self,
    const char *tag, const char *file, int line, const char *func)
{
    if (!__is_ao2_object(self, file, line, func)) {
        return NULL;
    }
 
    return __ao2_container_alloc_hash(ao2_options_get(self), self->common.options,
        self->n_buckets, self->hash_fn, self->common.sort_fn, self->common.cmp_fn,
        tag, file, line, func);
}
 
/*!
 * \internal
 * \brief Destroy a hash container list node.
 * \since 12.0.0
 *
 * \param v_doomed Container node to destroy.
 *
 * \details
 * The container node unlinks itself from the container as part
 * of its destruction.  The node must be destroyed while the
 * container is already locked.
 *
 * \note The container must be locked when the node is
 * unreferenced.
 */
static void hash_ao2_node_destructor(void *v_doomed)
{
    struct hash_bucket_node *doomed = v_doomed;
 
    if (doomed->common.is_linked) {
        struct ao2_container_hash *my_container;
        struct hash_bucket *bucket;
 
        /*
         * Promote to write lock if not already there.  Since
         * adjust_lock() can potentially release and block waiting for a
         * write lock, care must be taken to ensure that node references
         * are released before releasing the container references.
         *
         * Node references held by an iterator can only be held while
         * the iterator also holds a reference to the container.  These
         * node references must be unreferenced before the container can
         * be unreferenced to ensure that the node will not get a
         * negative reference and the destructor called twice for the
         * same node.
         */
        my_container = (struct ao2_container_hash *) doomed->common.my_container;
#ifdef AST_DEVMODE
        is_ao2_object(my_container);
#endif
 
        __adjust_lock(my_container, AO2_LOCK_REQ_WRLOCK, 1);
 
#if defined(AO2_DEBUG)
        if (!my_container->common.destroying
            && ao2_container_check(doomed->common.my_container, OBJ_NOLOCK)) {
            ast_log(LOG_ERROR, "Container integrity failed before node deletion.\n");
        }
#endif  /* defined(AO2_DEBUG) */
        bucket = &my_container->buckets[doomed->my_bucket];
        AST_DLLIST_REMOVE(&bucket->list, doomed, links);
        AO2_DEVMODE_STAT(--my_container->common.nodes);
    }
 
    /*
     * We could have an object in the node if the container is being
     * destroyed or the node had not been linked in yet.
     */
    if (doomed->common.obj) {
        __container_unlink_node(&doomed->common, AO2_UNLINK_NODE_UNLINK_OBJECT);
    }
}
 
/*!
 * \internal
 * \brief Create a new container node.
 * \since 12.0.0
 *
 * \param self Container to operate upon.
 * \param obj_new Object to put into the node.
 * \param tag used for debugging.
 * \param file Debug file name invoked from
 * \param line Debug line invoked from
 * \param func Debug function name invoked from
 *
 * \return initialized-node on success.
 * \retval NULL on error.
 */
static struct hash_bucket_node *hash_ao2_new_node(struct ao2_container_hash *self, void *obj_new, const char *tag, const char *file, int line, const char *func)
{
    struct hash_bucket_node *node;
    int i;
 
    node = ao2_alloc_options(sizeof(*node), hash_ao2_node_destructor,
        AO2_ALLOC_OPT_LOCK_NOLOCK | AO2_ALLOC_OPT_NO_REF_DEBUG);
    if (!node) {
        return NULL;
    }
 
    i = abs(self->hash_fn(obj_new, OBJ_SEARCH_OBJECT) % self->n_buckets);
 
    __ao2_ref(obj_new, +1, tag ?: "Container node creation", file, line, func);
    node->common.obj = obj_new;
    node->common.my_container = (struct ao2_container *) self;
    node->my_bucket = i;
 
    return node;
}
 
/*!
 * \internal
 * \brief Insert a node into this container.
 * \since 12.0.0
 *
 * \param self Container to operate upon.
 * \param node Container node to insert into the container.
 *
 * \return \ref ao2_container_insert value.
 */
static enum ao2_container_insert hash_ao2_insert_node(struct ao2_container_hash *self,
    struct hash_bucket_node *node)
{
    int cmp;
    struct hash_bucket *bucket;
    struct hash_bucket_node *cur;
    ao2_sort_fn *sort_fn;
    uint32_t options;
 
    bucket = &self->buckets[node->my_bucket];
    sort_fn = self->common.sort_fn;
    options = self->common.options;
 
    if (options & AO2_CONTAINER_ALLOC_OPT_INSERT_BEGIN) {
        if (sort_fn) {
            AST_DLLIST_TRAVERSE_BACKWARDS_SAFE_BEGIN(&bucket->list, cur, links) {
                cmp = sort_fn(cur->common.obj, node->common.obj, OBJ_SEARCH_OBJECT);
                if (cmp > 0) {
                    continue;
                }
                if (cmp < 0) {
                    AST_DLLIST_INSERT_AFTER_CURRENT(node, links);
                    return AO2_CONTAINER_INSERT_NODE_INSERTED;
                }
                switch (options & AO2_CONTAINER_ALLOC_OPT_DUPS_MASK) {
                default:
                case AO2_CONTAINER_ALLOC_OPT_DUPS_ALLOW:
                    break;
                case AO2_CONTAINER_ALLOC_OPT_DUPS_REJECT:
                    /* Reject all objects with the same key. */
                    return AO2_CONTAINER_INSERT_NODE_REJECTED;
                case AO2_CONTAINER_ALLOC_OPT_DUPS_OBJ_REJECT:
                    if (cur->common.obj == node->common.obj) {
                        /* Reject inserting the same object */
                        return AO2_CONTAINER_INSERT_NODE_REJECTED;
                    }
                    break;
                case AO2_CONTAINER_ALLOC_OPT_DUPS_REPLACE:
                    SWAP(cur->common.obj, node->common.obj);
                    ao2_ref(node, -1);
                    return AO2_CONTAINER_INSERT_NODE_OBJ_REPLACED;
                }
            }
            AST_DLLIST_TRAVERSE_BACKWARDS_SAFE_END;
        }
        AST_DLLIST_INSERT_HEAD(&bucket->list, node, links);
    } else {
        if (sort_fn) {
            AST_DLLIST_TRAVERSE_SAFE_BEGIN(&bucket->list, cur, links) {
                cmp = sort_fn(cur->common.obj, node->common.obj, OBJ_SEARCH_OBJECT);
                if (cmp < 0) {
                    continue;
                }
                if (cmp > 0) {
                    AST_DLLIST_INSERT_BEFORE_CURRENT(node, links);
                    return AO2_CONTAINER_INSERT_NODE_INSERTED;
                }
                switch (options & AO2_CONTAINER_ALLOC_OPT_DUPS_MASK) {
                default:
                case AO2_CONTAINER_ALLOC_OPT_DUPS_ALLOW:
                    break;
                case AO2_CONTAINER_ALLOC_OPT_DUPS_REJECT:
                    /* Reject all objects with the same key. */
                    return AO2_CONTAINER_INSERT_NODE_REJECTED;
                case AO2_CONTAINER_ALLOC_OPT_DUPS_OBJ_REJECT:
                    if (cur->common.obj == node->common.obj) {
                        /* Reject inserting the same object */
                        return AO2_CONTAINER_INSERT_NODE_REJECTED;
                    }
                    break;
                case AO2_CONTAINER_ALLOC_OPT_DUPS_REPLACE:
                    SWAP(cur->common.obj, node->common.obj);
                    ao2_ref(node, -1);
                    return AO2_CONTAINER_INSERT_NODE_OBJ_REPLACED;
                }
            }
            AST_DLLIST_TRAVERSE_SAFE_END;
        }
        AST_DLLIST_INSERT_TAIL(&bucket->list, node, links);
    }
    return AO2_CONTAINER_INSERT_NODE_INSERTED;
}
 
/*!
 * \internal
 * \brief Find the first hash container node in a traversal.
 * \since 12.0.0
 *
 * \param self Container to operate upon.
 * \param flags search_flags to control traversing the container
 * \param arg Comparison callback arg parameter.
 * \param state Traversal state to restart hash container traversal.
 *
 * \return node-ptr of found node (Reffed).
 * \retval NULL when no node found.
 */
static struct hash_bucket_node *hash_ao2_find_first(struct ao2_container_hash *self, enum search_flags flags, void *arg, struct hash_traversal_state *state)
{
    struct hash_bucket_node *node;
    int bucket_cur;
    int cmp;
 
    memset(state, 0, sizeof(*state));
    state->arg = arg;
    state->flags = flags;
 
    /* Determine traversal order. */
    switch (flags & OBJ_ORDER_MASK) {
    case OBJ_ORDER_POST:
    case OBJ_ORDER_DESCENDING:
        state->descending = 1;
        break;
    case OBJ_ORDER_PRE:
    case OBJ_ORDER_ASCENDING:
    default:
        break;
    }
 
    /*
     * If lookup by pointer or search key, run the hash and optional
     * sort functions.  Otherwise, traverse the whole container.
     */
    switch (flags & OBJ_SEARCH_MASK) {
    case OBJ_SEARCH_OBJECT:
    case OBJ_SEARCH_KEY:
        /* we know hash can handle this case */
        bucket_cur = abs(self->hash_fn(arg, flags & OBJ_SEARCH_MASK)
                % self->n_buckets);
        state->sort_fn = self->common.sort_fn;
        break;
    case OBJ_SEARCH_PARTIAL_KEY:
        /* scan all buckets for partial key matches */
        bucket_cur = -1;
        state->sort_fn = self->common.sort_fn;
        break;
    default:
        /* don't know, let's scan all buckets */
        bucket_cur = -1;
        state->sort_fn = NULL;
        break;
    }
 
    if (state->descending) {
        /*
         * Determine the search boundaries of a descending traversal.
         *
         * bucket_cur downto state->bucket_last
         */
        if (bucket_cur < 0) {
            bucket_cur = self->n_buckets - 1;
            state->bucket_last = 0;
        } else {
            state->bucket_last = bucket_cur;
        }
        state->bucket_start = bucket_cur;
 
        /* For each bucket */
        for (; state->bucket_last <= bucket_cur; --bucket_cur) {
            /* For each node in the bucket. */
            for (node = AST_DLLIST_LAST(&self->buckets[bucket_cur].list);
                node;
                node = AST_DLLIST_PREV(node, links)) {
                if (!node->common.obj) {
                    /* Node is empty */
                    continue;
                }
 
                if (state->sort_fn) {
                    /* Filter node through the sort_fn */
                    cmp = state->sort_fn(node->common.obj, arg, flags & OBJ_SEARCH_MASK);
                    if (cmp > 0) {
                        continue;
                    }
                    if (cmp < 0) {
                        /* No more nodes in this bucket are possible to match. */
                        break;
                    }
                }
 
                /* We have the first traversal node */
                ao2_ref(node, +1);
                return node;
            }
        }
    } else {
        /*
         * Determine the search boundaries of an ascending traversal.
         *
         * bucket_cur to state->bucket_last-1
         */
        if (bucket_cur < 0) {
            bucket_cur = 0;
            state->bucket_last = self->n_buckets;
        } else {
            state->bucket_last = bucket_cur + 1;
        }
        state->bucket_start = bucket_cur;
 
        /* For each bucket */
        for (; bucket_cur < state->bucket_last; ++bucket_cur) {
            /* For each node in the bucket. */
            for (node = AST_DLLIST_FIRST(&self->buckets[bucket_cur].list);
                node;
                node = AST_DLLIST_NEXT(node, links)) {
                if (!node->common.obj) {
                    /* Node is empty */
                    continue;
                }
 
                if (state->sort_fn) {
                    /* Filter node through the sort_fn */
                    cmp = state->sort_fn(node->common.obj, arg, flags & OBJ_SEARCH_MASK);
                    if (cmp < 0) {
                        continue;
                    }
                    if (cmp > 0) {
                        /* No more nodes in this bucket are possible to match. */
                        break;
                    }
                }
 
                /* We have the first traversal node */
                ao2_ref(node, +1);
                return node;
            }
        }
    }
 
    return NULL;
}
 
/*!
 * \internal
 * \brief Find the next hash container node in a traversal.
 * \since 12.0.0
 *
 * \param self Container to operate upon.
 * \param state Traversal state to restart hash container traversal.
 * \param prev Previous node returned by the traversal search functions.
 *    The ref ownership is passed back to this function.
 *
 * \return node-ptr of found node (Reffed).
 * \retval NULL when no node found.
 */
static struct hash_bucket_node *hash_ao2_find_next(struct ao2_container_hash *self, struct hash_traversal_state *state, struct hash_bucket_node *prev)
{
    struct hash_bucket_node *node;
    void *arg;
    enum search_flags flags;
    int bucket_cur;
    int cmp;
 
    arg = state->arg;
    flags = state->flags;
    bucket_cur = prev->my_bucket;
    node = prev;
 
    /*
     * This function is structured the same as hash_ao2_find_first()
     * intentionally.  We are resuming the search loops from
     * hash_ao2_find_first() in order to find the next node.  The
     * search loops must be resumed where hash_ao2_find_first()
     * returned with the first node.
     */
    if (state->descending) {
        goto hash_descending_resume;
 
        /* For each bucket */
        for (; state->bucket_last <= bucket_cur; --bucket_cur) {
            /* For each node in the bucket. */
            for (node = AST_DLLIST_LAST(&self->buckets[bucket_cur].list);
                node;
                node = AST_DLLIST_PREV(node, links)) {
                if (!node->common.obj) {
                    /* Node is empty */
                    continue;
                }
 
                if (state->sort_fn) {
                    /* Filter node through the sort_fn */
                    cmp = state->sort_fn(node->common.obj, arg, flags & OBJ_SEARCH_MASK);
                    if (cmp > 0) {
                        continue;
                    }
                    if (cmp < 0) {
                        /* No more nodes in this bucket are possible to match. */
                        break;
                    }
                }
 
                /* We have the next traversal node */
                ao2_ref(node, +1);
 
                /*
                 * Dereferencing the prev node may result in our next node
                 * object being removed by another thread.  This could happen if
                 * the container uses RW locks and the container was read
                 * locked.
                 */
                ao2_ref(prev, -1);
                if (node->common.obj) {
                    return node;
                }
                prev = node;
 
hash_descending_resume:;
            }
        }
    } else {
        goto hash_ascending_resume;
 
        /* For each bucket */
        for (; bucket_cur < state->bucket_last; ++bucket_cur) {
            /* For each node in the bucket. */
            for (node = AST_DLLIST_FIRST(&self->buckets[bucket_cur].list);
                node;
                node = AST_DLLIST_NEXT(node, links)) {
                if (!node->common.obj) {
                    /* Node is empty */
                    continue;
                }
 
                if (state->sort_fn) {
                    /* Filter node through the sort_fn */
                    cmp = state->sort_fn(node->common.obj, arg, flags & OBJ_SEARCH_MASK);
                    if (cmp < 0) {
                        continue;
                    }
                    if (cmp > 0) {
                        /* No more nodes in this bucket are possible to match. */
                        break;
                    }
                }
 
                /* We have the next traversal node */
                ao2_ref(node, +1);
 
                /*
                 * Dereferencing the prev node may result in our next node
                 * object being removed by another thread.  This could happen if
                 * the container uses RW locks and the container was read
                 * locked.
                 */
                ao2_ref(prev, -1);
                if (node->common.obj) {
                    return node;
                }
                prev = node;
 
hash_ascending_resume:;
            }
        }
    }
 
    /* No more nodes in the container left to traverse. */
    ao2_ref(prev, -1);
    return NULL;
}
 
/*!
 * \internal
 * \brief Find the next non-empty iteration node in the container.
 * \since 12.0.0
 *
 * \param self Container to operate upon.
 * \param node Previous node returned by the iterator.
 * \param flags search_flags to control iterating the container.
 *   Only AO2_ITERATOR_DESCENDING is useful by the method.
 *
 * \note The container is already locked.
 *
 * \return node on success.
 * \retval NULL on error or no more nodes in the container.
 */
static struct hash_bucket_node *hash_ao2_iterator_next(struct ao2_container_hash *self, struct hash_bucket_node *node, enum ao2_iterator_flags flags)
{
    int cur_bucket;
 
    if (flags & AO2_ITERATOR_DESCENDING) {
        if (node) {
            cur_bucket = node->my_bucket;
 
            /* Find next non-empty node. */
            for (;;) {
                node = AST_DLLIST_PREV(node, links);
                if (!node) {
                    break;
                }
                if (node->common.obj) {
                    /* Found a non-empty node. */
                    return node;
                }
            }
        } else {
            /* Find first non-empty node. */
            cur_bucket = self->n_buckets;
        }
 
        /* Find a non-empty node in the remaining buckets */
        while (0 <= --cur_bucket) {
            node = AST_DLLIST_LAST(&self->buckets[cur_bucket].list);
            while (node) {
                if (node->common.obj) {
                    /* Found a non-empty node. */
                    return node;
                }
                node = AST_DLLIST_PREV(node, links);
            }
        }
    } else {
        if (node) {
            cur_bucket = node->my_bucket;
 
            /* Find next non-empty node. */
            for (;;) {
                node = AST_DLLIST_NEXT(node, links);
                if (!node) {
                    break;
                }
                if (node->common.obj) {
                    /* Found a non-empty node. */
                    return node;
                }
            }
        } else {
            /* Find first non-empty node. */
            cur_bucket = -1;
        }
 
        /* Find a non-empty node in the remaining buckets */
        while (++cur_bucket < self->n_buckets) {
            node = AST_DLLIST_FIRST(&self->buckets[cur_bucket].list);
            while (node) {
                if (node->common.obj) {
                    /* Found a non-empty node. */
                    return node;
                }
                node = AST_DLLIST_NEXT(node, links);
            }
        }
    }
 
    /* No more nodes to visit in the container. */
    return NULL;
}
 
#if defined(AO2_DEBUG)
/*!
 * \internal
 * \brief Increment the hash container linked object statistic.
 * \since 12.0.0
 *
 * \param hash Container to operate upon.
 * \param hash_node Container node linking object to.
 */
static void hash_ao2_link_node_stat(struct ao2_container *hash, struct ao2_container_node *hash_node)
{
    struct ao2_container_hash *self = (struct ao2_container_hash *) hash;
    struct hash_bucket_node *node = (struct hash_bucket_node *) hash_node;
    int i = node->my_bucket;
 
    ++self->buckets[i].elements;
    if (self->buckets[i].max_elements < self->buckets[i].elements) {
        self->buckets[i].max_elements = self->buckets[i].elements;
    }
}
#endif  /* defined(AO2_DEBUG) */
 
#if defined(AO2_DEBUG)
/*!
 * \internal
 * \brief Decrement the hash container linked object statistic.
 * \since 12.0.0
 *
 * \param hash Container to operate upon.
 * \param hash_node Container node unlinking object from.
 */
static void hash_ao2_unlink_node_stat(struct ao2_container *hash, struct ao2_container_node *hash_node)
{
    struct ao2_container_hash *self = (struct ao2_container_hash *) hash;
    struct hash_bucket_node *node = (struct hash_bucket_node *) hash_node;
 
    --self->buckets[node->my_bucket].elements;
}
#endif  /* defined(AO2_DEBUG) */
 
/*!
 * \internal
 *
 * \brief Destroy this container.
 * \since 12.0.0
 *
 * \param self Container to operate upon.
 */
static void hash_ao2_destroy(struct ao2_container_hash *self)
{
    int idx;
 
    /* Check that the container no longer has any nodes */
    for (idx = self->n_buckets; idx--;) {
        if (!AST_DLLIST_EMPTY(&self->buckets[idx].list)) {
            ast_log(LOG_ERROR, "Node ref leak.  Hash container still has nodes!\n");
            ast_assert(0);
            break;
        }
    }
}
 
#if defined(AO2_DEBUG)
/*!
 * \internal
 * \brief Display contents of the specified container.
 * \since 12.0.0
 *
 * \param self Container to dump.
 * \param where User data needed by prnt to determine where to put output.
 * \param prnt Print output callback function to use.
 * \param prnt_obj Callback function to print the given object's key. (NULL if not available)
 */
static void hash_ao2_dump(struct ao2_container_hash *self, void *where, ao2_prnt_fn *prnt, ao2_prnt_obj_fn *prnt_obj)
{
#define FORMAT  "%6s, %16s, %16s, %16s, %16s, %s\n"
#define FORMAT2 "%6d, %16p, %16p, %16p, %16p, "
 
    int bucket;
    int suppressed_buckets = 0;
    struct hash_bucket_node *node;
 
    prnt(where, "Number of buckets: %d\n\n", self->n_buckets);
 
    prnt(where, FORMAT, "Bucket", "Node", "Prev", "Next", "Obj", "Key");
    for (bucket = 0; bucket < self->n_buckets; ++bucket) {
        node = AST_DLLIST_FIRST(&self->buckets[bucket].list);
        if (node) {
            suppressed_buckets = 0;
            do {
                prnt(where, FORMAT2,
                    bucket,
                    node,
                    AST_DLLIST_PREV(node, links),
                    AST_DLLIST_NEXT(node, links),
                    node->common.obj);
                if (node->common.obj && prnt_obj) {
                    prnt_obj(node->common.obj, where, prnt);
                }
                prnt(where, "\n");
 
                node = AST_DLLIST_NEXT(node, links);
            } while (node);
        } else if (!suppressed_buckets) {
            suppressed_buckets = 1;
            prnt(where, "...\n");
        }
    }
 
#undef FORMAT
#undef FORMAT2
}
#endif  /* defined(AO2_DEBUG) */
 
#if defined(AO2_DEBUG)
/*!
 * \internal
 * \brief Display statistics of the specified container.
 * \since 12.0.0
 *
 * \param self Container to display statistics.
 * \param where User data needed by prnt to determine where to put output.
 * \param prnt Print output callback function to use.
 *
 * \note The container is already locked for reading.
 */
static void hash_ao2_stats(struct ao2_container_hash *self, void *where, ao2_prnt_fn *prnt)
{
#define FORMAT  "%10.10s %10.10s %10.10s\n"
#define FORMAT2 "%10d %10d %10d\n"
 
    int bucket;
    int suppressed_buckets = 0;
 
    prnt(where, "Number of buckets: %d\n\n", self->n_buckets);
 
    prnt(where, FORMAT, "Bucket", "Objects", "Max");
    for (bucket = 0; bucket < self->n_buckets; ++bucket) {
        if (self->buckets[bucket].max_elements) {
            suppressed_buckets = 0;
            prnt(where, FORMAT2, bucket, self->buckets[bucket].elements,
                self->buckets[bucket].max_elements);
        } else if (!suppressed_buckets) {
            suppressed_buckets = 1;
            prnt(where, "...\n");
        }
    }
 
#undef FORMAT
#undef FORMAT2
}
#endif  /* defined(AO2_DEBUG) */
 
#if defined(AO2_DEBUG)
/*!
 * \internal
 * \brief Perform an integrity check on the specified container.
 * \since 12.0.0
 *
 * \param self Container to check integrity.
 *
 * \note The container is already locked for reading.
 *
 * \retval 0 on success.
 * \retval -1 on error.
 */
static int hash_ao2_integrity(struct ao2_container_hash *self)
{
    int bucket_exp;
    int bucket;
    int count_obj;
    int count_total_obj;
    int count_total_node;
    void *obj_last;
    struct hash_bucket_node *node;
    struct hash_bucket_node *prev;
    struct hash_bucket_node *next;
 
    count_total_obj = 0;
    count_total_node = 0;
 
    /* For each bucket in the container. */
    for (bucket = 0; bucket < self->n_buckets; ++bucket) {
        if (!AST_DLLIST_FIRST(&self->buckets[bucket].list)
            && !AST_DLLIST_LAST(&self->buckets[bucket].list)) {
            /* The bucket list is empty. */
            continue;
        }
 
        count_obj = 0;
        obj_last = NULL;
 
        /* Check bucket list links and nodes. */
        node = AST_DLLIST_LAST(&self->buckets[bucket].list);
        if (!node) {
            ast_log(LOG_ERROR, "Bucket %d list tail is NULL when it should not be!\n",
                bucket);
            return -1;
        }
        if (AST_DLLIST_NEXT(node, links)) {
            ast_log(LOG_ERROR, "Bucket %d list tail node is not the last node!\n",
                bucket);
            return -1;
        }
        node = AST_DLLIST_FIRST(&self->buckets[bucket].list);
        if (!node) {
            ast_log(LOG_ERROR, "Bucket %d list head is NULL when it should not be!\n",
                bucket);
            return -1;
        }
        if (AST_DLLIST_PREV(node, links)) {
            ast_log(LOG_ERROR, "Bucket %d list head node is not the first node!\n",
                bucket);
            return -1;
        }
        for (; node; node = next) {
            /* Check backward link. */
            prev = AST_DLLIST_PREV(node, links);
            if (prev) {
                if (prev == node) {
                    ast_log(LOG_ERROR, "Bucket %d list node's prev pointer points to itself!\n",
                        bucket);
                    return -1;
                }
                if (node != AST_DLLIST_NEXT(prev, links)) {
                    ast_log(LOG_ERROR, "Bucket %d list node's prev node does not link back!\n",
                        bucket);
                    return -1;
                }
            } else if (node != AST_DLLIST_FIRST(&self->buckets[bucket].list)) {
                ast_log(LOG_ERROR, "Bucket %d backward list chain is broken!\n",
                    bucket);
                return -1;
            }
 
            /* Check forward link. */
            next = AST_DLLIST_NEXT(node, links);
            if (next) {
                if (next == node) {
                    ast_log(LOG_ERROR, "Bucket %d list node's next pointer points to itself!\n",
                        bucket);
                    return -1;
                }
                if (node != AST_DLLIST_PREV(next, links)) {
                    ast_log(LOG_ERROR, "Bucket %d list node's next node does not link back!\n",
                        bucket);
                    return -1;
                }
            } else if (node != AST_DLLIST_LAST(&self->buckets[bucket].list)) {
                ast_log(LOG_ERROR, "Bucket %d forward list chain is broken!\n",
                    bucket);
                return -1;
            }
 
            if (bucket != node->my_bucket) {
                ast_log(LOG_ERROR, "Bucket %d node claims to be in bucket %d!\n",
                    bucket, node->my_bucket);
                return -1;
            }
 
            ++count_total_node;
            if (!node->common.obj) {
                /* Node is empty. */
                continue;
            }
            ++count_obj;
 
            /* Check container hash key for expected bucket. */
            bucket_exp = abs(self->hash_fn(node->common.obj, OBJ_SEARCH_OBJECT)
                    % self->n_buckets);
            if (bucket != bucket_exp) {
                ast_log(LOG_ERROR, "Bucket %d node hashes to bucket %d!\n",
                    bucket, bucket_exp);
                return -1;
            }
 
            /* Check sort if configured. */
            if (self->common.sort_fn) {
                if (obj_last
                    && self->common.sort_fn(obj_last, node->common.obj, OBJ_SEARCH_OBJECT) > 0) {
                    ast_log(LOG_ERROR, "Bucket %d nodes out of sorted order!\n",
                        bucket);
                    return -1;
                }
                obj_last = node->common.obj;
            }
        }
 
        /* Check bucket obj count statistic. */
        if (count_obj != self->buckets[bucket].elements) {
            ast_log(LOG_ERROR, "Bucket %d object count of %d does not match stat of %d!\n",
                bucket, count_obj, self->buckets[bucket].elements);
            return -1;
        }
 
        /* Accumulate found object counts. */
        count_total_obj += count_obj;
    }
 
    /* Check total obj count. */
    if (count_total_obj != ao2_container_count(&self->common)) {
        ast_log(LOG_ERROR,
            "Total object count of %d does not match ao2_container_count() of %d!\n",
            count_total_obj, ao2_container_count(&self->common));
        return -1;
    }
 
    /* Check total node count. */
    if (count_total_node != self->common.nodes) {
        ast_log(LOG_ERROR, "Total node count of %d does not match stat of %d!\n",
            count_total_node, self->common.nodes);
        return -1;
    }
 
    return 0;
}
#endif  /* defined(AO2_DEBUG) */
 
/*! Hash container virtual method table. */
static const struct ao2_container_methods v_table_hash = {
    .alloc_empty_clone = (ao2_container_alloc_empty_clone_fn) hash_ao2_alloc_empty_clone,
    .new_node = (ao2_container_new_node_fn) hash_ao2_new_node,
    .insert = (ao2_container_insert_fn) hash_ao2_insert_node,
    .traverse_first = (ao2_container_find_first_fn) hash_ao2_find_first,
    .traverse_next = (ao2_container_find_next_fn) hash_ao2_find_next,
    .iterator_next = (ao2_iterator_next_fn) hash_ao2_iterator_next,
    .destroy = (ao2_container_destroy_fn) hash_ao2_destroy,
#if defined(AO2_DEBUG)
    .link_stat = hash_ao2_link_node_stat,
    .unlink_stat = hash_ao2_unlink_node_stat,
    .dump = (ao2_container_display) hash_ao2_dump,
    .stats = (ao2_container_statistics) hash_ao2_stats,
    .integrity = (ao2_container_integrity) hash_ao2_integrity,
#endif  /* defined(AO2_DEBUG) */
};
 
/*!
 * \brief always zero hash function
 *
 * it is convenient to have a hash function that always returns 0.
 * This is basically used when we want to have a container that is
 * a simple linked list.
 *
 * \retval 0
 */
static int hash_zero(const void *user_obj, const int flags)
{
    return 0;
}
 
/*!
 * \brief Initialize a hash container with the desired number of buckets.
 *
 * \param self Container to initialize.
 * \param options Container behaviour options (See enum ao2_container_opts)
 * \param n_buckets Number of buckets for hash
 * \param hash_fn Pointer to a function computing a hash value.
 * \param sort_fn Pointer to a sort function.
 * \param cmp_fn Pointer to a compare function used by ao2_find.
 *
 * \return A pointer to a struct container.
 */
static struct ao2_container *hash_ao2_container_init(
    struct ao2_container_hash *self, unsigned int options, unsigned int n_buckets,
    ao2_hash_fn *hash_fn, ao2_sort_fn *sort_fn, ao2_callback_fn *cmp_fn)
{
    if (!self) {
        return NULL;
    }
 
    self->common.v_table = &v_table_hash;
    self->common.sort_fn = sort_fn;
    self->common.cmp_fn = cmp_fn;
    self->common.options = options;
    self->hash_fn = hash_fn ? hash_fn : hash_zero;
    self->n_buckets = n_buckets;
 
#ifdef AO2_DEBUG
    ast_atomic_fetchadd_int(&ao2.total_containers, 1);
#endif  /* defined(AO2_DEBUG) */
 
    return (struct ao2_container *) self;
}
 
struct ao2_container *__ao2_container_alloc_hash(unsigned int ao2_options,
    unsigned int container_options, unsigned int n_buckets, ao2_hash_fn *hash_fn,
    ao2_sort_fn *sort_fn, ao2_callback_fn *cmp_fn,
    const char *tag, const char *file, int line, const char *func)
{
    unsigned int num_buckets;
    size_t container_size;
    struct ao2_container_hash *self;
 
    num_buckets = hash_fn ? n_buckets : 1;
    container_size = sizeof(struct ao2_container_hash) + num_buckets * sizeof(struct hash_bucket);
 
    self = __ao2_alloc(container_size, container_destruct, ao2_options,
        tag ?: __PRETTY_FUNCTION__, file, line, func);
    return hash_ao2_container_init(self, container_options, num_buckets, hash_fn,
        sort_fn, cmp_fn);
}
 
struct ao2_container *__ao2_container_alloc_list(unsigned int ao2_options,
    unsigned int container_options, ao2_sort_fn *sort_fn, ao2_callback_fn *cmp_fn,
    const char *tag, const char *file, int line, const char *func)
{
    return __ao2_container_alloc_hash(ao2_options, container_options, 1, NULL,
        sort_fn, cmp_fn, tag, file, line, func);
}