From f8247040e6231c4b3b5099ea3a526348b7941566 Mon Sep 17 00:00:00 2001 From: russell Date: Sat, 19 Jan 2008 00:19:29 +0000 Subject: Creating tag for the release of asterisk-1.6.0-beta1 git-svn-id: http://svn.digium.com/svn/asterisk/tags/1.6.0-beta1@99163 f38db490-d61c-443f-a65b-d21fe96a405b --- trunk/main/astobj2.c | 732 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 732 insertions(+) create mode 100644 trunk/main/astobj2.c (limited to 'trunk/main/astobj2.c') diff --git a/trunk/main/astobj2.c b/trunk/main/astobj2.c new file mode 100644 index 000000000..2d3611889 --- /dev/null +++ b/trunk/main/astobj2.c @@ -0,0 +1,732 @@ +/* + * astobj2 - replacement containers for asterisk data structures. + * + * 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. + */ + +/* + * Function implementing astobj2 objects. + */ +#include "asterisk.h" + +ASTERISK_FILE_VERSION(__FILE__, "$Revision$") + +#include "asterisk/_private.h" +#include "asterisk/astobj2.h" +#include "asterisk/utils.h" +#include "asterisk/cli.h" + +/*! + * astobj2 objects are always preceded by this data structure, + * which contains a lock, a reference counter, + * the flags and a pointer to a destructor. + * The refcount is used to decide when it is time to + * invoke the destructor. + * The magic number is used for consistency check. + * XXX the lock is not always needed, and its initialization may be + * expensive. Consider making it external. + */ +struct __priv_data { + ast_mutex_t lock; + int ref_counter; + ao2_destructor_fn destructor_fn; + /*! for stats */ + size_t data_size; + /*! magic number. This is used to verify that a pointer passed in is a + * valid astobj2 */ + uint32_t magic; +}; + +#define AO2_MAGIC 0xa570b123 + +/*! + * What an astobj2 object looks like: fixed-size private data + * followed by variable-size user data. + */ +struct astobj2 { + struct __priv_data priv_data; + void *user_data[0]; +}; + +#ifdef AST_DEVMODE +#define AO2_DEBUG 1 +#endif + +#ifdef AO2_DEBUG +struct ao2_stats { + volatile int total_objects; + volatile int total_mem; + volatile int total_containers; + volatile int total_refs; + volatile int total_locked; +}; + +static struct ao2_stats ao2; +#endif + +#ifndef HAVE_BKTR /* backtrace support */ +void ao2_bt(void) {} +#else +#include /* for backtrace */ + +void ao2_bt(void) +{ + int c, i; +#define N1 20 + void *addresses[N1]; + char **strings; + + c = backtrace(addresses, N1); + strings = backtrace_symbols(addresses,c); + ast_verbose("backtrace returned: %d\n", c); + for(i = 0; i < c; i++) { + ast_verbose("%d: %p %s\n", i, addresses[i], strings[i]); + } + free(strings); +} +#endif + +/*! + * \brief convert from a pointer _p to a user-defined object + * + * \return the pointer to the astobj2 structure + */ +static inline struct astobj2 *INTERNAL_OBJ(void *user_data) +{ + struct astobj2 *p; + + if (!user_data) { + ast_log(LOG_ERROR, "user_data is NULL\n"); + return NULL; + } + + p = (struct astobj2 *) ((char *) user_data - sizeof(*p)); + if (AO2_MAGIC != (p->priv_data.magic) ) { + ast_log(LOG_ERROR, "bad magic number 0x%x for %p\n", p->priv_data.magic, p); + p = NULL; + } + + return p; +} + +/*! + * \brief convert from a pointer _p to an astobj2 object + * + * \return the pointer to the user-defined portion. + */ +#define EXTERNAL_OBJ(_p) ((_p) == NULL ? NULL : (_p)->user_data) + +int ao2_lock(void *user_data) +{ + struct astobj2 *p = INTERNAL_OBJ(user_data); + + if (p == NULL) + return -1; + +#ifdef AO2_DEBUG + ast_atomic_fetchadd_int(&ao2.total_locked, 1); +#endif + + return ast_mutex_lock(&p->priv_data.lock); +} + +int ao2_unlock(void *user_data) +{ + struct astobj2 *p = INTERNAL_OBJ(user_data); + + if (p == NULL) + return -1; + +#ifdef AO2_DEBUG + ast_atomic_fetchadd_int(&ao2.total_locked, -1); +#endif + + return ast_mutex_unlock(&p->priv_data.lock); +} + +/* + * The argument is a pointer to the user portion. + */ +int ao2_ref(void *user_data, const int delta) +{ + int current_value; + int ret; + struct astobj2 *obj = INTERNAL_OBJ(user_data); + + if (obj == NULL) + return -1; + + /* if delta is 0, just return the refcount */ + if (delta == 0) + return (obj->priv_data.ref_counter); + + /* we modify with an atomic operation the reference counter */ + ret = ast_atomic_fetchadd_int(&obj->priv_data.ref_counter, delta); + current_value = ret + delta; + +#ifdef AO2_DEBUG + ast_atomic_fetchadd_int(&ao2.total_refs, delta); +#endif + + /* this case must never happen */ + if (current_value < 0) + ast_log(LOG_ERROR, "refcount %d on object %p\n", current_value, user_data); + + if (current_value <= 0) { /* last reference, destroy the object */ + if (obj->priv_data.destructor_fn != NULL) + obj->priv_data.destructor_fn(user_data); + + ast_mutex_destroy(&obj->priv_data.lock); +#ifdef AO2_DEBUG + ast_atomic_fetchadd_int(&ao2.total_mem, - obj->priv_data.data_size); + ast_atomic_fetchadd_int(&ao2.total_objects, -1); +#endif + /* for safety, zero-out the astobj2 header and also the + * first word of the user-data, which we make sure is always + * allocated. */ + bzero(obj, sizeof(struct astobj2 *) + sizeof(void *) ); + free(obj); + } + + return ret; +} + +/* + * We always alloc at least the size of a void *, + * for debugging purposes. + */ +void *ao2_alloc(size_t data_size, ao2_destructor_fn destructor_fn) +{ + /* allocation */ + struct astobj2 *obj; + + if (data_size < sizeof(void *)) + data_size = sizeof(void *); + + obj = ast_calloc(1, sizeof(*obj) + data_size); + + if (obj == NULL) + return NULL; + + ast_mutex_init(&obj->priv_data.lock); + obj->priv_data.magic = AO2_MAGIC; + obj->priv_data.data_size = data_size; + obj->priv_data.ref_counter = 1; + obj->priv_data.destructor_fn = destructor_fn; /* can be NULL */ + +#ifdef AO2_DEBUG + ast_atomic_fetchadd_int(&ao2.total_objects, 1); + ast_atomic_fetchadd_int(&ao2.total_mem, data_size); + ast_atomic_fetchadd_int(&ao2.total_refs, 1); +#endif + + /* return a pointer to the user data */ + return EXTERNAL_OBJ(obj); +} + +/* internal callback to destroy a container. */ +static void container_destruct(void *c); + +/* each bucket in the container is a tailq. */ +AST_LIST_HEAD_NOLOCK(bucket, bucket_list); + +/*! + * A container; stores the hash and callback functions, information on + * the size, the hash bucket heads, and a version number, starting at 0 + * (for a newly created, empty container) + * and incremented every time an object is inserted or deleted. + * The assumption is that an object is never moved in a container, + * but removed and readded with the new number. + * The version number is especially useful when implementing iterators. + * In fact, we can associate a unique, monotonically increasing number to + * each object, which means that, within an iterator, we can store the + * version number of the current object, and easily look for the next one, + * which is the next one in the list with a higher number. + * Since all objects have a version >0, we can use 0 as a marker for + * 'we need the first object in the bucket'. + * + * \todo Linking and unlink objects is typically expensive, as it + * involves a malloc() of a small object which is very inefficient. + * To optimize this, we allocate larger arrays of bucket_list's + * when we run out of them, and then manage our own freelist. + * This will be more efficient as we can do the freelist management while + * we hold the lock (that we need anyways). + */ +struct ao2_container { + ao2_hash_fn *hash_fn; + ao2_callback_fn *cmp_fn; + int n_buckets; + /*! Number of elements in the container */ + int elements; + /*! described above */ + int version; + /*! variable size */ + struct bucket buckets[0]; +}; + +/*! + * \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. + * + * \returns 0 + */ +static int hash_zero(const void *user_obj, const int flags) +{ + return 0; +} + +/* + * A container is just an object, after all! + */ +struct ao2_container * +ao2_container_alloc(const uint n_buckets, ao2_hash_fn *hash_fn, + ao2_callback_fn *cmp_fn) +{ + /* XXX maybe consistency check on arguments ? */ + /* compute the container size */ + size_t container_size = sizeof(struct ao2_container) + n_buckets * sizeof(struct bucket); + + struct ao2_container *c = ao2_alloc(container_size, container_destruct); + + if (!c) + return NULL; + + c->version = 1; /* 0 is a reserved value here */ + c->n_buckets = n_buckets; + c->hash_fn = hash_fn ? hash_fn : hash_zero; + c->cmp_fn = cmp_fn; + +#ifdef AO2_DEBUG + ast_atomic_fetchadd_int(&ao2.total_containers, 1); +#endif + + return c; +} + +/*! + * return the number of elements in the container + */ +int ao2_container_count(struct ao2_container *c) +{ + return c->elements; +} + +/*! + * A structure to create a linked list of entries, + * used within a bucket. + * XXX \todo this should be private to the container code + */ +struct bucket_list { + AST_LIST_ENTRY(bucket_list) entry; + int version; + struct astobj2 *astobj; /* pointer to internal data */ +}; + +/* + * link an object to a container + */ +void *ao2_link(struct ao2_container *c, void *user_data) +{ + int i; + /* create a new list entry */ + struct bucket_list *p; + struct astobj2 *obj = INTERNAL_OBJ(user_data); + + if (!obj) + return NULL; + + if (INTERNAL_OBJ(c) == NULL) + return NULL; + + p = ast_calloc(1, sizeof(*p)); + if (!p) + return NULL; + + i = c->hash_fn(user_data, OBJ_POINTER); + + ao2_lock(c); + i %= c->n_buckets; + p->astobj = obj; + p->version = ast_atomic_fetchadd_int(&c->version, 1); + AST_LIST_INSERT_TAIL(&c->buckets[i], p, entry); + ast_atomic_fetchadd_int(&c->elements, 1); + ao2_ref(user_data, +1); + ao2_unlock(c); + + return p; +} + +/*! + * \brief another convenience function is a callback that matches on address + */ +int ao2_match_by_addr(void *user_data, void *arg, int flags) +{ + return (user_data == arg) ? (CMP_MATCH | CMP_STOP) : 0; +} + +/* + * Unlink an object from the container + * and destroy the associated * ao2_bucket_list structure. + */ +void *ao2_unlink(struct ao2_container *c, void *user_data) +{ + if (INTERNAL_OBJ(user_data) == NULL) /* safety check on the argument */ + return NULL; + + ao2_callback(c, OBJ_UNLINK | OBJ_POINTER | OBJ_NODATA, ao2_match_by_addr, user_data); + + return NULL; +} + +/*! + * \brief special callback that matches all + */ +static int cb_true(void *user_data, void *arg, int flags) +{ + return CMP_MATCH; +} + +/*! + * Browse the container using different stategies accoding the flags. + * \return Is a pointer to an object or to a list of object if OBJ_MULTIPLE is + * specified. + */ +void *ao2_callback(struct ao2_container *c, + const enum search_flags flags, + ao2_callback_fn *cb_fn, void *arg) +{ + int i, last; /* search boundaries */ + void *ret = NULL; + + if (INTERNAL_OBJ(c) == NULL) /* safety check on the argument */ + return NULL; + + if ((flags & (OBJ_MULTIPLE | OBJ_NODATA)) == OBJ_MULTIPLE) { + ast_log(LOG_WARNING, "multiple data return not implemented yet (flags %x)\n", flags); + return NULL; + } + + /* override the match function if necessary */ + if (cb_fn == NULL) /* if NULL, match everything */ + cb_fn = cb_true; + /* + * XXX this can be optimized. + * If we have a hash function and lookup by pointer, + * run the hash function. Otherwise, scan the whole container + * (this only for the time being. We need to optimize this.) + */ + if ((flags & OBJ_POINTER)) /* we know hash can handle this case */ + i = c->hash_fn(arg, flags & OBJ_POINTER) % c->n_buckets; + else /* don't know, let's scan all buckets */ + i = -1; /* XXX this must be fixed later. */ + + /* determine the search boundaries: i..last-1 */ + if (i < 0) { + i = 0; + last = c->n_buckets; + } else { + last = i + 1; + } + + ao2_lock(c); /* avoid modifications to the content */ + + for (; i < last ; i++) { + /* scan the list with prev-cur pointers */ + struct bucket_list *cur; + + AST_LIST_TRAVERSE_SAFE_BEGIN(&c->buckets[i], cur, entry) { + int match = cb_fn(EXTERNAL_OBJ(cur->astobj), arg, flags) & (CMP_MATCH | CMP_STOP); + + /* we found the object, performing operations according flags */ + if (match == 0) { /* no match, no stop, continue */ + continue; + } else if (match == CMP_STOP) { /* no match but stop, we are done */ + i = last; + break; + } + /* we have a match (CMP_MATCH) here */ + if (!(flags & OBJ_NODATA)) { /* if must return the object, record the value */ + /* it is important to handle this case before the unlink */ + ret = EXTERNAL_OBJ(cur->astobj); + ao2_ref(ret, 1); + } + + if (flags & OBJ_UNLINK) { /* must unlink */ + struct bucket_list *x = cur; + + /* we are going to modify the container, so update version */ + ast_atomic_fetchadd_int(&c->version, 1); + AST_LIST_REMOVE_CURRENT(entry); + /* update number of elements and version */ + ast_atomic_fetchadd_int(&c->elements, -1); + ao2_ref(EXTERNAL_OBJ(x->astobj), -1); + free(x); /* free the link record */ + } + + if ((match & CMP_STOP) || (flags & OBJ_MULTIPLE) == 0) { + /* We found the only match we need */ + i = last; /* force exit from outer loop */ + break; + } + if (!(flags & OBJ_NODATA)) { +#if 0 /* XXX to be completed */ + /* + * This is the multiple-return case. We need to link + * the object in a list. The refcount is already increased. + */ +#endif + } + } + AST_LIST_TRAVERSE_SAFE_END; + } + ao2_unlock(c); + return ret; +} + +/*! + * the find function just invokes the default callback with some reasonable flags. + */ +void *ao2_find(struct ao2_container *c, void *arg, enum search_flags flags) +{ + return ao2_callback(c, flags, c->cmp_fn, arg); +} + +/*! + * initialize an iterator so we start from the first object + */ +struct ao2_iterator ao2_iterator_init(struct ao2_container *c, int flags) +{ + struct ao2_iterator a = { + .c = c, + .flags = flags + }; + + return a; +} + +/* + * move to the next element in the container. + */ +void * ao2_iterator_next(struct ao2_iterator *a) +{ + int lim; + struct bucket_list *p = NULL; + void *ret = NULL; + + if (INTERNAL_OBJ(a->c) == NULL) + return NULL; + + if (!(a->flags & F_AO2I_DONTLOCK)) + ao2_lock(a->c); + + /* optimization. If the container is unchanged and + * we have a pointer, try follow it + */ + if (a->c->version == a->c_version && (p = a->obj) ) { + if ( (p = AST_LIST_NEXT(p, entry)) ) + goto found; + /* nope, start from the next bucket */ + a->bucket++; + a->version = 0; + a->obj = NULL; + } + + lim = a->c->n_buckets; + + /* Browse the buckets array, moving to the next + * buckets if we don't find the entry in the current one. + * Stop when we find an element with version number greater + * than the current one (we reset the version to 0 when we + * switch buckets). + */ + for (; a->bucket < lim; a->bucket++, a->version = 0) { + /* scan the current bucket */ + AST_LIST_TRAVERSE(&a->c->buckets[a->bucket], p, entry) { + if (p->version > a->version) + goto found; + } + } + +found: + if (p) { + a->version = p->version; + a->obj = p; + a->c_version = a->c->version; + ret = EXTERNAL_OBJ(p->astobj); + /* inc refcount of returned object */ + ao2_ref(ret, 1); + } + + if (!(a->flags & F_AO2I_DONTLOCK)) + ao2_unlock(a->c); + + return ret; +} + +/* callback for destroying container. + * we can make it simple as we know what it does + */ +static int cd_cb(void *obj, void *arg, int flag) +{ + ao2_ref(obj, -1); + return 0; +} + +static void container_destruct(void *_c) +{ + struct ao2_container *c = _c; + + ao2_callback(c, OBJ_UNLINK, cd_cb, NULL); + +#ifdef AO2_DEBUG + ast_atomic_fetchadd_int(&ao2.total_containers, -1); +#endif +} + +#ifdef AO2_DEBUG +static int print_cb(void *obj, void *arg, int flag) +{ + int *fd = arg; + char *s = (char *)obj; + + ast_cli(*fd, "string <%s>\n", s); + return 0; +} + +/* + * Print stats + */ +static char *handle_astobj2_stats(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a) +{ + switch (cmd) { + case CLI_INIT: + e->command = "astobj2 stats"; + e->usage = "Usage: astobj2 stats\n" + " Show astobj2 stats\n"; + return NULL; + case CLI_GENERATE: + return NULL; + } + ast_cli(a->fd, "Objects : %d\n", ao2.total_objects); + ast_cli(a->fd, "Containers : %d\n", ao2.total_containers); + ast_cli(a->fd, "Memory : %d\n", ao2.total_mem); + ast_cli(a->fd, "Locked : %d\n", ao2.total_locked); + ast_cli(a->fd, "Refs : %d\n", ao2.total_refs); + return CLI_SUCCESS; +} + +/* + * This is testing code for astobj + */ +static char *handle_astobj2_test(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a) +{ + struct ao2_container *c1; + int i, lim; + char *obj; + static int prof_id = -1; + struct ast_cli_args fake_args = { a->fd, 0, NULL }; + + switch (cmd) { + case CLI_INIT: + e->command = "astobj2 test"; + e->usage = "Usage: astobj2 test \n" + " Runs astobj2 test. Creates 'num' objects,\n" + " and test iterators, callbacks and may be other stuff\n"; + return NULL; + case CLI_GENERATE: + return NULL; + } + + if (a->argc != 3) { + return CLI_SHOWUSAGE; + } + + if (prof_id == -1) + prof_id = ast_add_profile("ao2_alloc", 0); + + ast_cli(a->fd, "argc %d argv %s %s %s\n", a->argc, a->argv[0], a->argv[1], a->argv[2]); + lim = atoi(a->argv[2]); + ast_cli(a->fd, "called astobj_test\n"); + + handle_astobj2_stats(e, CLI_HANDLER, &fake_args); + /* + * allocate a container with no default callback, and no hash function. + * No hash means everything goes in the same bucket. + */ + c1 = ao2_container_alloc(100, NULL /* no callback */, NULL /* no hash */); + ast_cli(a->fd, "container allocated as %p\n", c1); + + /* + * fill the container with objects. + * ao2_alloc() gives us a reference which we pass to the + * container when we do the insert. + */ + for (i = 0; i < lim; i++) { + ast_mark(prof_id, 1 /* start */); + obj = ao2_alloc(80, NULL); + ast_mark(prof_id, 0 /* stop */); + ast_cli(a->fd, "object %d allocated as %p\n", i, obj); + sprintf(obj, "-- this is obj %d --", i); + ao2_link(c1, obj); + } + ast_cli(a->fd, "testing callbacks\n"); + ao2_callback(c1, 0, print_cb, &a->fd); + + ast_cli(a->fd, "testing iterators, remove every second object\n"); + { + struct ao2_iterator ai; + int x = 0; + + ai = ao2_iterator_init(c1, 0); + while ( (obj = ao2_iterator_next(&ai)) ) { + ast_cli(a->fd, "iterator on <%s>\n", obj); + if (x++ & 1) + ao2_unlink(c1, obj); + ao2_ref(obj, -1); + } + ast_cli(a->fd, "testing iterators again\n"); + ai = ao2_iterator_init(c1, 0); + while ( (obj = ao2_iterator_next(&ai)) ) { + ast_cli(a->fd, "iterator on <%s>\n", obj); + ao2_ref(obj, -1); + } + } + ast_cli(a->fd, "testing callbacks again\n"); + ao2_callback(c1, 0, print_cb, &a->fd); + + ast_verbose("now you should see an error message:\n"); + ao2_ref(&i, -1); /* i is not a valid object so we print an error here */ + + ast_cli(a->fd, "destroy container\n"); + ao2_ref(c1, -1); /* destroy container */ + handle_astobj2_stats(e, CLI_HANDLER, &fake_args); + return CLI_SUCCESS; +} + +static struct ast_cli_entry cli_astobj2[] = { + AST_CLI_DEFINE(handle_astobj2_stats, "Print astobj2 statistics"), + AST_CLI_DEFINE(handle_astobj2_test, "Test astobj2"), +}; +#endif /* AO2_DEBUG */ + +int astobj2_init(void) +{ +#ifdef AO2_DEBUG + ast_cli_register_multiple(cli_astobj2, ARRAY_LEN(cli_astobj2)); +#endif + + return 0; +} -- cgit v1.2.3