Wed Aug 18 22:33:44 2010

Asterisk developer's documentation


astobj2.c

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00001 /*
00002  * astobj2 - replacement containers for asterisk data structures.
00003  *
00004  * Copyright (C) 2006 Marta Carbone, Luigi Rizzo - Univ. di Pisa, Italy
00005  *
00006  * See http://www.asterisk.org for more information about
00007  * the Asterisk project. Please do not directly contact
00008  * any of the maintainers of this project for assistance;
00009  * the project provides a web site, mailing lists and IRC
00010  * channels for your use.
00011  *
00012  * This program is free software, distributed under the terms of
00013  * the GNU General Public License Version 2. See the LICENSE file
00014  * at the top of the source tree.
00015  */
00016 
00017 /*
00018  * Function implementing astobj2 objects.
00019  */
00020 #include "asterisk.h"
00021 
00022 ASTERISK_FILE_VERSION(__FILE__, "$Revision: 254717 $")
00023 
00024 #include "asterisk/_private.h"
00025 #include "asterisk/astobj2.h"
00026 #include "asterisk/utils.h"
00027 #include "asterisk/cli.h"
00028 #define REF_FILE "/tmp/refs"
00029 
00030 /*!
00031  * astobj2 objects are always preceded by this data structure,
00032  * which contains a lock, a reference counter,
00033  * the flags and a pointer to a destructor.
00034  * The refcount is used to decide when it is time to
00035  * invoke the destructor.
00036  * The magic number is used for consistency check.
00037  * XXX the lock is not always needed, and its initialization may be
00038  * expensive. Consider making it external.
00039  */
00040 struct __priv_data {
00041    ast_mutex_t lock;
00042    int ref_counter;
00043    ao2_destructor_fn destructor_fn;
00044    /*! for stats */
00045    size_t data_size;
00046    /*! magic number.  This is used to verify that a pointer passed in is a
00047     *  valid astobj2 */
00048    uint32_t magic;
00049 };
00050 
00051 #define  AO2_MAGIC   0xa570b123
00052 
00053 /*!
00054  * What an astobj2 object looks like: fixed-size private data
00055  * followed by variable-size user data.
00056  */
00057 struct astobj2 {
00058    struct __priv_data priv_data;
00059    void *user_data[0];
00060 };
00061 
00062 #ifdef AST_DEVMODE
00063 #define AO2_DEBUG 1
00064 #endif
00065 
00066 #ifdef AO2_DEBUG
00067 struct ao2_stats {
00068    volatile int total_objects;
00069    volatile int total_mem;
00070    volatile int total_containers;
00071    volatile int total_refs;
00072    volatile int total_locked;
00073 };
00074 
00075 static struct ao2_stats ao2;
00076 #endif
00077 
00078 #ifndef HAVE_BKTR /* backtrace support */
00079 void ao2_bt(void) {}
00080 #else
00081 #include <execinfo.h>    /* for backtrace */
00082 
00083 void ao2_bt(void)
00084 {
00085    int c, i;
00086 #define N1  20
00087    void *addresses[N1];
00088    char **strings;
00089 
00090    c = backtrace(addresses, N1);
00091    strings = backtrace_symbols(addresses,c);
00092    ast_verbose("backtrace returned: %d\n", c);
00093    for(i = 0; i < c; i++) {
00094       ast_verbose("%d: %p %s\n", i, addresses[i], strings[i]);
00095    }
00096    free(strings);
00097 }
00098 #endif
00099 
00100 /*!
00101  * \brief convert from a pointer _p to a user-defined object
00102  *
00103  * \return the pointer to the astobj2 structure
00104  */
00105 static inline struct astobj2 *INTERNAL_OBJ(void *user_data)
00106 {
00107    struct astobj2 *p;
00108 
00109    if (!user_data) {
00110       ast_log(LOG_ERROR, "user_data is NULL\n");
00111       return NULL;
00112    }
00113 
00114    p = (struct astobj2 *) ((char *) user_data - sizeof(*p));
00115    if (AO2_MAGIC != (p->priv_data.magic) ) {
00116       ast_log(LOG_ERROR, "bad magic number 0x%x for %p\n", p->priv_data.magic, p);
00117       p = NULL;
00118    }
00119 
00120    return p;
00121 }
00122 
00123 /*!
00124  * \brief convert from a pointer _p to an astobj2 object
00125  *
00126  * \return the pointer to the user-defined portion.
00127  */
00128 #define EXTERNAL_OBJ(_p)   ((_p) == NULL ? NULL : (_p)->user_data)
00129 
00130 /* the underlying functions common to debug and non-debug versions */
00131 
00132 static int __ao2_ref(void *user_data, const int delta);
00133 static struct ao2_container *__ao2_container_alloc(struct ao2_container *c, const uint n_buckets, ao2_hash_fn *hash_fn,
00134                                  ao2_callback_fn *cmp_fn);
00135 static struct bucket_list *__ao2_link(struct ao2_container *c, void *user_data);
00136 static void *__ao2_callback(struct ao2_container *c,
00137    const enum search_flags flags, ao2_callback_fn *cb_fn, void *arg,
00138                 char *tag, char *file, int line, const char *funcname);
00139 static void * __ao2_iterator_next(struct ao2_iterator *a, struct bucket_list **q);
00140 
00141 #ifdef DEBUG_THREADS
00142 /* Need to override the macros defined in astobj2.h */
00143 #undef ao2_lock
00144 #undef ao2_trylock
00145 #undef ao2_unlock
00146 #endif
00147 
00148 int ao2_lock(void *user_data)
00149 {
00150    struct astobj2 *p = INTERNAL_OBJ(user_data);
00151 
00152    if (p == NULL)
00153       return -1;
00154 
00155 #ifdef AO2_DEBUG
00156    ast_atomic_fetchadd_int(&ao2.total_locked, 1);
00157 #endif
00158 
00159    return ast_mutex_lock(&p->priv_data.lock);
00160 }
00161 
00162 int _ao2_lock(void *user_data, const char *file, const char *func, int line, const char *var)
00163 {
00164    struct astobj2 *p = INTERNAL_OBJ(user_data);
00165 
00166    if (p == NULL)
00167       return -1;
00168 
00169 #ifdef AO2_DEBUG
00170    ast_atomic_fetchadd_int(&ao2.total_locked, 1);
00171 #endif
00172 
00173 #ifndef DEBUG_THREADS
00174    return ast_mutex_lock(&p->priv_data.lock);
00175 #else
00176    return __ast_pthread_mutex_lock(file, line, func, var, &p->priv_data.lock);
00177 #endif
00178 }
00179 
00180 int ao2_unlock(void *user_data)
00181 {
00182    struct astobj2 *p = INTERNAL_OBJ(user_data);
00183 
00184    if (p == NULL)
00185       return -1;
00186 
00187 #ifdef AO2_DEBUG
00188    ast_atomic_fetchadd_int(&ao2.total_locked, -1);
00189 #endif
00190 
00191    return ast_mutex_unlock(&p->priv_data.lock);
00192 }
00193 
00194 int _ao2_unlock(void *user_data, const char *file, const char *func, int line, const char *var)
00195 {
00196    struct astobj2 *p = INTERNAL_OBJ(user_data);
00197 
00198    if (p == NULL)
00199       return -1;
00200 
00201 #ifdef AO2_DEBUG
00202    ast_atomic_fetchadd_int(&ao2.total_locked, -1);
00203 #endif
00204 
00205 #ifndef DEBUG_THREADS
00206    return ast_mutex_unlock(&p->priv_data.lock);
00207 #else
00208    return __ast_pthread_mutex_unlock(file, line, func, var, &p->priv_data.lock);
00209 #endif
00210 }
00211 
00212 int ao2_trylock(void *user_data)
00213 {
00214    struct astobj2 *p = INTERNAL_OBJ(user_data);
00215    int ret;
00216    
00217    if (p == NULL)
00218       return -1;
00219    ret = ast_mutex_trylock(&p->priv_data.lock);
00220 
00221 #ifdef AO2_DEBUG
00222    if (!ret)
00223       ast_atomic_fetchadd_int(&ao2.total_locked, 1);
00224 #endif
00225    return ret;
00226 }
00227 
00228 int _ao2_trylock(void *user_data, const char *file, const char *func, int line, const char *var)
00229 {
00230    struct astobj2 *p = INTERNAL_OBJ(user_data);
00231    int ret;
00232    
00233    if (p == NULL)
00234       return -1;
00235 #ifndef DEBUG_THREADS
00236    ret = ast_mutex_trylock(&p->priv_data.lock);
00237 #else
00238    ret = __ast_pthread_mutex_trylock(file, line, func, var, &p->priv_data.lock);
00239 #endif
00240 
00241 #ifdef AO2_DEBUG
00242    if (!ret)
00243       ast_atomic_fetchadd_int(&ao2.total_locked, 1);
00244 #endif
00245    return ret;
00246 }
00247 
00248 void *ao2_object_get_lockaddr(void *obj)
00249 {
00250    struct astobj2 *p = INTERNAL_OBJ(obj);
00251    
00252    if (p == NULL)
00253       return NULL;
00254 
00255    return &p->priv_data.lock;
00256 }
00257 
00258 /*
00259  * The argument is a pointer to the user portion.
00260  */
00261 
00262 
00263 int _ao2_ref_debug(void *user_data, const int delta, char *tag, char *file, int line, const char *funcname)
00264 {
00265    struct astobj2 *obj = INTERNAL_OBJ(user_data);
00266    
00267    if (obj == NULL)
00268       return -1;
00269 
00270    if (delta != 0) {
00271       FILE *refo = fopen(REF_FILE,"a");
00272       fprintf(refo, "%p %s%d   %s:%d:%s (%s) [@%d]\n", user_data, (delta<0? "":"+"), delta, file, line, funcname, tag, obj->priv_data.ref_counter);
00273       fclose(refo);
00274    }
00275    if (obj->priv_data.ref_counter + delta == 0 && obj->priv_data.destructor_fn != NULL) { /* this isn't protected with lock; just for o/p */
00276          FILE *refo = fopen(REF_FILE,"a");    
00277          fprintf(refo, "%p **call destructor** %s:%d:%s (%s)\n", user_data, file, line, funcname, tag);   
00278          fclose(refo);
00279    }
00280    return __ao2_ref(user_data, delta);
00281 }
00282 
00283 int _ao2_ref(void *user_data, const int delta)
00284 {
00285    struct astobj2 *obj = INTERNAL_OBJ(user_data);
00286 
00287    if (obj == NULL)
00288       return -1;
00289 
00290    return __ao2_ref(user_data, delta);
00291 }
00292 
00293 static int __ao2_ref(void *user_data, const int delta)
00294 {
00295    struct astobj2 *obj = INTERNAL_OBJ(user_data);
00296    int current_value;
00297    int ret;
00298 
00299    if (obj == NULL)
00300       return -1;
00301 
00302    /* if delta is 0, just return the refcount */
00303    if (delta == 0)
00304       return (obj->priv_data.ref_counter);
00305 
00306    /* we modify with an atomic operation the reference counter */
00307    ret = ast_atomic_fetchadd_int(&obj->priv_data.ref_counter, delta);
00308    current_value = ret + delta;
00309 
00310 #ifdef AO2_DEBUG  
00311    ast_atomic_fetchadd_int(&ao2.total_refs, delta);
00312 #endif
00313 
00314    /* this case must never happen */
00315    if (current_value < 0)
00316       ast_log(LOG_ERROR, "refcount %d on object %p\n", current_value, user_data);
00317 
00318    if (current_value <= 0) { /* last reference, destroy the object */
00319       if (obj->priv_data.destructor_fn != NULL) {
00320          obj->priv_data.destructor_fn(user_data);
00321       }
00322 
00323       ast_mutex_destroy(&obj->priv_data.lock);
00324 #ifdef AO2_DEBUG
00325       ast_atomic_fetchadd_int(&ao2.total_mem, - obj->priv_data.data_size);
00326       ast_atomic_fetchadd_int(&ao2.total_objects, -1);
00327 #endif
00328       /* for safety, zero-out the astobj2 header and also the
00329        * first word of the user-data, which we make sure is always
00330        * allocated. */
00331       memset(obj, '\0', sizeof(struct astobj2 *) + sizeof(void *) );
00332       free(obj);
00333    }
00334 
00335    return ret;
00336 }
00337 
00338 /*
00339  * We always alloc at least the size of a void *,
00340  * for debugging purposes.
00341  */
00342 static void *__ao2_alloc(size_t data_size, ao2_destructor_fn destructor_fn, const char *file, int line, const char *funcname)
00343 {
00344    /* allocation */
00345    struct astobj2 *obj;
00346 
00347    if (data_size < sizeof(void *))
00348       data_size = sizeof(void *);
00349 
00350 #if defined(__AST_DEBUG_MALLOC)
00351    obj = __ast_calloc(1, sizeof(*obj) + data_size, file, line, funcname);
00352 #else
00353    obj = ast_calloc(1, sizeof(*obj) + data_size);
00354 #endif
00355 
00356    if (obj == NULL)
00357       return NULL;
00358 
00359    ast_mutex_init(&obj->priv_data.lock);
00360    obj->priv_data.magic = AO2_MAGIC;
00361    obj->priv_data.data_size = data_size;
00362    obj->priv_data.ref_counter = 1;
00363    obj->priv_data.destructor_fn = destructor_fn;   /* can be NULL */
00364 
00365 #ifdef AO2_DEBUG
00366    ast_atomic_fetchadd_int(&ao2.total_objects, 1);
00367    ast_atomic_fetchadd_int(&ao2.total_mem, data_size);
00368    ast_atomic_fetchadd_int(&ao2.total_refs, 1);
00369 #endif
00370 
00371    /* return a pointer to the user data */
00372    return EXTERNAL_OBJ(obj);
00373 }
00374 
00375 void *_ao2_alloc_debug(size_t data_size, ao2_destructor_fn destructor_fn, char *tag,
00376          const char *file, int line, const char *funcname, int ref_debug)
00377 {
00378    /* allocation */
00379    void *obj;
00380    FILE *refo = ref_debug ? fopen(REF_FILE,"a") : NULL;
00381 
00382    obj = __ao2_alloc(data_size, destructor_fn, file, line, funcname);
00383 
00384    if (obj == NULL)
00385       return NULL;
00386    
00387    if (refo) {
00388       fprintf(refo, "%p =1   %s:%d:%s (%s)\n", obj, file, line, funcname, tag);
00389       fclose(refo);
00390    }
00391 
00392    /* return a pointer to the user data */
00393    return obj;
00394 }
00395 
00396 void *_ao2_alloc(size_t data_size, ao2_destructor_fn destructor_fn)
00397 {
00398    return __ao2_alloc(data_size, destructor_fn, __FILE__, __LINE__, __FUNCTION__);
00399 }
00400 
00401 
00402 /* internal callback to destroy a container. */
00403 static void container_destruct(void *c);
00404 
00405 /* internal callback to destroy a container. */
00406 static void container_destruct_debug(void *c);
00407 
00408 /* each bucket in the container is a tailq. */
00409 AST_LIST_HEAD_NOLOCK(bucket, bucket_list);
00410 
00411 /*!
00412  * A container; stores the hash and callback functions, information on
00413  * the size, the hash bucket heads, and a version number, starting at 0
00414  * (for a newly created, empty container)
00415  * and incremented every time an object is inserted or deleted.
00416  * The assumption is that an object is never moved in a container,
00417  * but removed and readded with the new number.
00418  * The version number is especially useful when implementing iterators.
00419  * In fact, we can associate a unique, monotonically increasing number to
00420  * each object, which means that, within an iterator, we can store the
00421  * version number of the current object, and easily look for the next one,
00422  * which is the next one in the list with a higher number.
00423  * Since all objects have a version >0, we can use 0 as a marker for
00424  * 'we need the first object in the bucket'.
00425  *
00426  * \todo Linking and unlink objects is typically expensive, as it
00427  * involves a malloc() of a small object which is very inefficient.
00428  * To optimize this, we allocate larger arrays of bucket_list's
00429  * when we run out of them, and then manage our own freelist.
00430  * This will be more efficient as we can do the freelist management while
00431  * we hold the lock (that we need anyways).
00432  */
00433 struct ao2_container {
00434    ao2_hash_fn *hash_fn;
00435    ao2_callback_fn *cmp_fn;
00436    int n_buckets;
00437    /*! Number of elements in the container */
00438    int elements;
00439    /*! described above */
00440    int version;
00441    /*! variable size */
00442    struct bucket buckets[0];
00443 };
00444  
00445 /*!
00446  * \brief always zero hash function
00447  *
00448  * it is convenient to have a hash function that always returns 0.
00449  * This is basically used when we want to have a container that is
00450  * a simple linked list.
00451  *
00452  * \returns 0
00453  */
00454 static int hash_zero(const void *user_obj, const int flags)
00455 {
00456    return 0;
00457 }
00458 
00459 /*
00460  * A container is just an object, after all!
00461  */
00462 static struct ao2_container *__ao2_container_alloc(struct ao2_container *c, const unsigned int n_buckets, ao2_hash_fn *hash_fn,
00463                                  ao2_callback_fn *cmp_fn)
00464 {
00465    /* XXX maybe consistency check on arguments ? */
00466    /* compute the container size */
00467 
00468    if (!c)
00469       return NULL;
00470    
00471    c->version = 1;   /* 0 is a reserved value here */
00472    c->n_buckets = n_buckets;
00473    c->hash_fn = hash_fn ? hash_fn : hash_zero;
00474    c->cmp_fn = cmp_fn;
00475 
00476 #ifdef AO2_DEBUG
00477    ast_atomic_fetchadd_int(&ao2.total_containers, 1);
00478 #endif
00479 
00480    return c;
00481 }
00482 
00483 struct ao2_container *_ao2_container_alloc_debug(const unsigned int n_buckets, ao2_hash_fn *hash_fn,
00484                     ao2_callback_fn *cmp_fn, char *tag, char *file, int line,
00485                     const char *funcname, int ref_debug)
00486 {
00487    /* XXX maybe consistency check on arguments ? */
00488    /* compute the container size */
00489    size_t container_size = sizeof(struct ao2_container) + n_buckets * sizeof(struct bucket);
00490    struct ao2_container *c = _ao2_alloc_debug(container_size, container_destruct_debug, tag, file, line, funcname, ref_debug);
00491 
00492    return __ao2_container_alloc(c, n_buckets, hash_fn, cmp_fn);
00493 }
00494 
00495 struct ao2_container *
00496 _ao2_container_alloc(const unsigned int n_buckets, ao2_hash_fn *hash_fn,
00497       ao2_callback_fn *cmp_fn)
00498 {
00499    /* XXX maybe consistency check on arguments ? */
00500    /* compute the container size */
00501 
00502    size_t container_size = sizeof(struct ao2_container) + n_buckets * sizeof(struct bucket);
00503    struct ao2_container *c = _ao2_alloc(container_size, container_destruct);
00504 
00505    return __ao2_container_alloc(c, n_buckets, hash_fn, cmp_fn);
00506 }
00507 
00508 /*!
00509  * return the number of elements in the container
00510  */
00511 int ao2_container_count(struct ao2_container *c)
00512 {
00513    return c->elements;
00514 }
00515 
00516 /*!
00517  * A structure to create a linked list of entries,
00518  * used within a bucket.
00519  * XXX \todo this should be private to the container code
00520  */
00521 struct bucket_list {
00522    AST_LIST_ENTRY(bucket_list) entry;
00523    int version;
00524    struct astobj2 *astobj;    /* pointer to internal data */
00525 }; 
00526 
00527 /*
00528  * link an object to a container
00529  */
00530 
00531 static struct bucket_list *__ao2_link(struct ao2_container *c, void *user_data)
00532 {
00533    int i;
00534    /* create a new list entry */
00535    struct bucket_list *p;
00536    struct astobj2 *obj = INTERNAL_OBJ(user_data);
00537    
00538    if (obj == NULL)
00539       return NULL;
00540 
00541    if (INTERNAL_OBJ(c) == NULL)
00542       return NULL;
00543 
00544    p = ast_calloc(1, sizeof(*p));
00545    if (!p)
00546       return NULL;
00547 
00548    i = abs(c->hash_fn(user_data, OBJ_POINTER));
00549 
00550    ao2_lock(c);
00551    i %= c->n_buckets;
00552    p->astobj = obj;
00553    p->version = ast_atomic_fetchadd_int(&c->version, 1);
00554    AST_LIST_INSERT_TAIL(&c->buckets[i], p, entry);
00555    ast_atomic_fetchadd_int(&c->elements, 1);
00556 
00557    /* the last two operations (ao2_ref, ao2_unlock) must be done by the calling func */
00558    return p;
00559 }
00560 
00561 void *_ao2_link_debug(struct ao2_container *c, void *user_data, char *tag, char *file, int line, const char *funcname)
00562 {
00563    struct bucket_list *p = __ao2_link(c, user_data);
00564    
00565    if (p) {
00566       _ao2_ref_debug(user_data, +1, tag, file, line, funcname);
00567       ao2_unlock(c);
00568    }
00569    return p;
00570 }
00571 
00572 void *_ao2_link(struct ao2_container *c, void *user_data)
00573 {
00574    struct bucket_list *p = __ao2_link(c, user_data);
00575    
00576    if (p) {
00577       _ao2_ref(user_data, +1);
00578       ao2_unlock(c);
00579    }
00580    return p;
00581 }
00582 
00583 /*!
00584  * \brief another convenience function is a callback that matches on address
00585  */
00586 int ao2_match_by_addr(void *user_data, void *arg, int flags)
00587 {
00588    return (user_data == arg) ? (CMP_MATCH | CMP_STOP) : 0;
00589 }
00590 
00591 /*
00592  * Unlink an object from the container
00593  * and destroy the associated * ao2_bucket_list structure.
00594  */
00595 void *_ao2_unlink_debug(struct ao2_container *c, void *user_data, char *tag,
00596                   char *file, int line, const char *funcname)
00597 {
00598    if (INTERNAL_OBJ(user_data) == NULL)   /* safety check on the argument */
00599       return NULL;
00600 
00601    _ao2_callback_debug(c, OBJ_UNLINK | OBJ_POINTER | OBJ_NODATA, ao2_match_by_addr, user_data, tag, file, line, funcname);
00602 
00603    return NULL;
00604 }
00605 
00606 void *_ao2_unlink(struct ao2_container *c, void *user_data)
00607 {
00608    if (INTERNAL_OBJ(user_data) == NULL)   /* safety check on the argument */
00609       return NULL;
00610 
00611    _ao2_callback(c, OBJ_UNLINK | OBJ_POINTER | OBJ_NODATA, ao2_match_by_addr, user_data);
00612 
00613    return NULL;
00614 }
00615 
00616 /*! 
00617  * \brief special callback that matches all 
00618  */ 
00619 static int cb_true(void *user_data, void *arg, int flags)
00620 {
00621    return CMP_MATCH;
00622 }
00623 
00624 /*!
00625  * Browse the container using different stategies accoding the flags.
00626  * \return Is a pointer to an object or to a list of object if OBJ_MULTIPLE is 
00627  * specified.
00628  * Luckily, for debug purposes, the added args (tag, file, line, funcname)
00629  * aren't an excessive load to the system, as the callback should not be
00630  * called as often as, say, the ao2_ref func is called.
00631  */
00632 static void *__ao2_callback(struct ao2_container *c,
00633    const enum search_flags flags, ao2_callback_fn *cb_fn, void *arg,
00634    char *tag, char *file, int line, const char *funcname)
00635 {
00636    int i, start, last;  /* search boundaries */
00637    void *ret = NULL;
00638 
00639    if (INTERNAL_OBJ(c) == NULL)  /* safety check on the argument */
00640       return NULL;
00641 
00642    if ((flags & (OBJ_MULTIPLE | OBJ_NODATA)) == OBJ_MULTIPLE) {
00643       ast_log(LOG_WARNING, "multiple data return not implemented yet (flags %x)\n", flags);
00644       return NULL;
00645    }
00646 
00647    /* override the match function if necessary */
00648    if (cb_fn == NULL)   /* if NULL, match everything */
00649       cb_fn = cb_true;
00650    /*
00651     * XXX this can be optimized.
00652     * If we have a hash function and lookup by pointer,
00653     * run the hash function. Otherwise, scan the whole container
00654     * (this only for the time being. We need to optimize this.)
00655     */
00656    if ((flags & OBJ_POINTER)) /* we know hash can handle this case */
00657       start = i = c->hash_fn(arg, flags & OBJ_POINTER) % c->n_buckets;
00658    else        /* don't know, let's scan all buckets */
00659       start = i = -1;      /* XXX this must be fixed later. */
00660 
00661    /* determine the search boundaries: i..last-1 */
00662    if (i < 0) {
00663       start = i = 0;
00664       last = c->n_buckets;
00665    } else if ((flags & OBJ_CONTINUE)) {
00666       last = c->n_buckets;
00667    } else {
00668       last = i + 1;
00669    }
00670 
00671    ao2_lock(c);   /* avoid modifications to the content */
00672 
00673    for (; i < last ; i++) {
00674       /* scan the list with prev-cur pointers */
00675       struct bucket_list *cur;
00676 
00677       AST_LIST_TRAVERSE_SAFE_BEGIN(&c->buckets[i], cur, entry) {
00678          int match = cb_fn(EXTERNAL_OBJ(cur->astobj), arg, flags) & (CMP_MATCH | CMP_STOP);
00679 
00680          /* we found the object, performing operations according flags */
00681          if (match == 0) { /* no match, no stop, continue */
00682             continue;
00683          } else if (match == CMP_STOP) {  /* no match but stop, we are done */
00684             i = last;
00685             break;
00686          }
00687          /* we have a match (CMP_MATCH) here */
00688          if (!(flags & OBJ_NODATA)) {  /* if must return the object, record the value */
00689             /* it is important to handle this case before the unlink */
00690             ret = EXTERNAL_OBJ(cur->astobj);
00691             if (tag)
00692                _ao2_ref_debug(ret, 1, tag, file, line, funcname);
00693             else
00694                _ao2_ref(ret, 1);
00695          }
00696 
00697          if (flags & OBJ_UNLINK) {  /* must unlink */
00698             struct bucket_list *x = cur;
00699 
00700             /* we are going to modify the container, so update version */
00701             ast_atomic_fetchadd_int(&c->version, 1);
00702             AST_LIST_REMOVE_CURRENT(entry);
00703             /* update number of elements and version */
00704             ast_atomic_fetchadd_int(&c->elements, -1);
00705             if (tag)
00706                _ao2_ref_debug(EXTERNAL_OBJ(x->astobj), -1, tag, file, line, funcname);
00707             else
00708                _ao2_ref(EXTERNAL_OBJ(x->astobj), -1);
00709             free(x); /* free the link record */
00710          }
00711 
00712          if ((match & CMP_STOP) || (flags & OBJ_MULTIPLE) == 0) {
00713             /* We found the only match we need */
00714             i = last;   /* force exit from outer loop */
00715             break;
00716          }
00717          if (!(flags & OBJ_NODATA)) {
00718 #if 0 /* XXX to be completed */
00719             /*
00720              * This is the multiple-return case. We need to link
00721              * the object in a list. The refcount is already increased.
00722              */
00723 #endif
00724          }
00725       }
00726       AST_LIST_TRAVERSE_SAFE_END;
00727 
00728       if (ret) {
00729          /* This assumes OBJ_MULTIPLE with !OBJ_NODATA is still not implemented */
00730          break;
00731       }
00732 
00733       if (i == c->n_buckets - 1 && (flags & OBJ_POINTER) && (flags & OBJ_CONTINUE)) {
00734          /* Move to the beginning to ensure we check every bucket */
00735          i = -1;
00736          last = start;
00737       }
00738    }
00739    ao2_unlock(c);
00740    return ret;
00741 }
00742 
00743 void *_ao2_callback_debug(struct ao2_container *c,
00744                    const enum search_flags flags,
00745                    ao2_callback_fn *cb_fn, void *arg, 
00746                    char *tag, char *file, int line, const char *funcname)
00747 {
00748    return __ao2_callback(c,flags, cb_fn, arg, tag, file, line, funcname);
00749 }
00750 
00751 void *_ao2_callback(struct ao2_container *c,const enum search_flags flags,
00752                     ao2_callback_fn *cb_fn, void *arg)
00753 {
00754    return __ao2_callback(c,flags, cb_fn, arg, NULL, NULL, 0, NULL);
00755 }
00756 
00757 /*!
00758  * the find function just invokes the default callback with some reasonable flags.
00759  */
00760 void *_ao2_find_debug(struct ao2_container *c, void *arg, enum search_flags flags, char *tag, char *file, int line, const char *funcname)
00761 {
00762    return _ao2_callback_debug(c, flags, c->cmp_fn, arg, tag, file, line, funcname);
00763 }
00764 
00765 void *_ao2_find(struct ao2_container *c, void *arg, enum search_flags flags)
00766 {
00767    return _ao2_callback(c, flags, c->cmp_fn, arg);
00768 }
00769 
00770 /*!
00771  * initialize an iterator so we start from the first object
00772  */
00773 struct ao2_iterator ao2_iterator_init(struct ao2_container *c, int flags)
00774 {
00775    struct ao2_iterator a = {
00776       .c = c,
00777       .flags = flags
00778    };
00779 
00780    ao2_ref(c, +1);
00781    
00782    return a;
00783 }
00784 
00785 /*!
00786  * destroy an iterator
00787  */
00788 void ao2_iterator_destroy(struct ao2_iterator *i)
00789 {
00790    ao2_ref(i->c, -1);
00791    i->c = NULL;
00792 }
00793 
00794 /*
00795  * move to the next element in the container.
00796  */
00797 static void * __ao2_iterator_next(struct ao2_iterator *a, struct bucket_list **q)
00798 {
00799    int lim;
00800    struct bucket_list *p = NULL;
00801    void *ret = NULL;
00802 
00803    *q = NULL;
00804    
00805    if (INTERNAL_OBJ(a->c) == NULL)
00806       return NULL;
00807 
00808    if (!(a->flags & AO2_ITERATOR_DONTLOCK))
00809       ao2_lock(a->c);
00810 
00811    /* optimization. If the container is unchanged and
00812     * we have a pointer, try follow it
00813     */
00814    if (a->c->version == a->c_version && (p = a->obj) ) {
00815       if ( (p = AST_LIST_NEXT(p, entry)) )
00816          goto found;
00817       /* nope, start from the next bucket */
00818       a->bucket++;
00819       a->version = 0;
00820       a->obj = NULL;
00821    }
00822 
00823    lim = a->c->n_buckets;
00824 
00825    /* Browse the buckets array, moving to the next
00826     * buckets if we don't find the entry in the current one.
00827     * Stop when we find an element with version number greater
00828     * than the current one (we reset the version to 0 when we
00829     * switch buckets).
00830     */
00831    for (; a->bucket < lim; a->bucket++, a->version = 0) {
00832       /* scan the current bucket */
00833       AST_LIST_TRAVERSE(&a->c->buckets[a->bucket], p, entry) {
00834          if (p->version > a->version)
00835             goto found;
00836       }
00837    }
00838 
00839 found:
00840    if (p) {
00841       a->version = p->version;
00842       a->obj = p;
00843       a->c_version = a->c->version;
00844       ret = EXTERNAL_OBJ(p->astobj);
00845       /* inc refcount of returned object */
00846       *q = p;
00847    }
00848 
00849    return ret;
00850 }
00851 
00852 void * _ao2_iterator_next_debug(struct ao2_iterator *a, char *tag, char *file, int line, const char *funcname)
00853 {
00854    struct bucket_list *p;
00855    void *ret = NULL;
00856 
00857    ret = __ao2_iterator_next(a, &p);
00858    
00859    if (p) {
00860       /* inc refcount of returned object */
00861       _ao2_ref_debug(ret, 1, tag, file, line, funcname);
00862    }
00863 
00864    if (!(a->flags & AO2_ITERATOR_DONTLOCK))
00865       ao2_unlock(a->c);
00866 
00867    return ret;
00868 }
00869 
00870 void * _ao2_iterator_next(struct ao2_iterator *a)
00871 {
00872    struct bucket_list *p = NULL;
00873    void *ret = NULL;
00874 
00875    ret = __ao2_iterator_next(a, &p);
00876    
00877    if (p) {
00878       /* inc refcount of returned object */
00879       _ao2_ref(ret, 1);
00880    }
00881 
00882    if (!(a->flags & AO2_ITERATOR_DONTLOCK))
00883       ao2_unlock(a->c);
00884 
00885    return ret;
00886 }
00887 
00888 /* callback for destroying container.
00889  * we can make it simple as we know what it does
00890  */
00891 static int cd_cb(void *obj, void *arg, int flag)
00892 {
00893    _ao2_ref(obj, -1);
00894    return 0;
00895 }
00896    
00897 static int cd_cb_debug(void *obj, void *arg, int flag)
00898 {
00899    _ao2_ref_debug(obj, -1, "deref object via container destroy",  __FILE__, __LINE__, __PRETTY_FUNCTION__);
00900    return 0;
00901 }
00902    
00903 static void container_destruct(void *_c)
00904 {
00905    struct ao2_container *c = _c;
00906    int i;
00907 
00908    _ao2_callback(c, OBJ_UNLINK, cd_cb, NULL);
00909 
00910    for (i = 0; i < c->n_buckets; i++) {
00911       struct bucket_list *current;
00912 
00913       while ((current = AST_LIST_REMOVE_HEAD(&c->buckets[i], entry))) {
00914          ast_free(current);
00915       }
00916    }
00917 
00918 #ifdef AO2_DEBUG
00919    ast_atomic_fetchadd_int(&ao2.total_containers, -1);
00920 #endif
00921 }
00922 
00923 static void container_destruct_debug(void *_c)
00924 {
00925    struct ao2_container *c = _c;
00926    int i;
00927 
00928    _ao2_callback_debug(c, OBJ_UNLINK, cd_cb_debug, NULL, "container_destruct_debug called", __FILE__, __LINE__, __PRETTY_FUNCTION__);
00929 
00930    for (i = 0; i < c->n_buckets; i++) {
00931       struct bucket_list *current;
00932 
00933       while ((current = AST_LIST_REMOVE_HEAD(&c->buckets[i], entry))) {
00934          ast_free(current);
00935       }
00936    }
00937 
00938 #ifdef AO2_DEBUG
00939    ast_atomic_fetchadd_int(&ao2.total_containers, -1);
00940 #endif
00941 }
00942 
00943 #ifdef AO2_DEBUG
00944 static int print_cb(void *obj, void *arg, int flag)
00945 {
00946    int *fd = arg;
00947    char *s = (char *)obj;
00948 
00949    ast_cli(*fd, "string <%s>\n", s);
00950    return 0;
00951 }
00952 
00953 /*
00954  * Print stats
00955  */
00956 static char *handle_astobj2_stats(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
00957 {
00958    switch (cmd) {
00959    case CLI_INIT:
00960       e->command = "astobj2 stats";
00961       e->usage = "Usage: astobj2 stats\n"
00962             "       Show astobj2 stats\n";
00963       return NULL;
00964    case CLI_GENERATE:
00965       return NULL;
00966    }
00967    ast_cli(a->fd, "Objects    : %d\n", ao2.total_objects);
00968    ast_cli(a->fd, "Containers : %d\n", ao2.total_containers);
00969    ast_cli(a->fd, "Memory     : %d\n", ao2.total_mem);
00970    ast_cli(a->fd, "Locked     : %d\n", ao2.total_locked);
00971    ast_cli(a->fd, "Refs       : %d\n", ao2.total_refs);
00972    return CLI_SUCCESS;
00973 }
00974 
00975 /*
00976  * This is testing code for astobj
00977  */
00978 static char *handle_astobj2_test(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
00979 {
00980    struct ao2_container *c1;
00981    int i, lim;
00982    char *obj;
00983    static int prof_id = -1;
00984    struct ast_cli_args fake_args = { a->fd, 0, NULL };
00985 
00986    switch (cmd) {
00987    case CLI_INIT:
00988       e->command = "astobj2 test";
00989       e->usage = "Usage: astobj2 test <num>\n"
00990             "       Runs astobj2 test. Creates 'num' objects,\n"
00991             "       and test iterators, callbacks and may be other stuff\n";
00992       return NULL;
00993    case CLI_GENERATE:
00994       return NULL;
00995    }
00996 
00997    if (a->argc != 3) {
00998       return CLI_SHOWUSAGE;
00999    }
01000 
01001    if (prof_id == -1)
01002       prof_id = ast_add_profile("ao2_alloc", 0);
01003 
01004    ast_cli(a->fd, "argc %d argv %s %s %s\n", a->argc, a->argv[0], a->argv[1], a->argv[2]);
01005    lim = atoi(a->argv[2]);
01006    ast_cli(a->fd, "called astobj_test\n");
01007 
01008    handle_astobj2_stats(e, CLI_HANDLER, &fake_args);
01009    /*
01010     * allocate a container with no default callback, and no hash function.
01011     * No hash means everything goes in the same bucket.
01012     */
01013    c1 = ao2_t_container_alloc(100, NULL /* no callback */, NULL /* no hash */,"test");
01014    ast_cli(a->fd, "container allocated as %p\n", c1);
01015 
01016    /*
01017     * fill the container with objects.
01018     * ao2_alloc() gives us a reference which we pass to the
01019     * container when we do the insert.
01020     */
01021    for (i = 0; i < lim; i++) {
01022       ast_mark(prof_id, 1 /* start */);
01023       obj = ao2_t_alloc(80, NULL,"test");
01024       ast_mark(prof_id, 0 /* stop */);
01025       ast_cli(a->fd, "object %d allocated as %p\n", i, obj);
01026       sprintf(obj, "-- this is obj %d --", i);
01027       ao2_link(c1, obj);
01028       /* At this point, the refcount on obj is 2 due to the allocation
01029        * and linking. We can go ahead and reduce the refcount by 1
01030        * right here so that when the container is unreffed later, the
01031        * objects will be freed
01032        */
01033       ao2_t_ref(obj, -1, "test");
01034    }
01035    ast_cli(a->fd, "testing callbacks\n");
01036    ao2_t_callback(c1, 0, print_cb, &a->fd,"test callback");
01037    ast_cli(a->fd, "testing iterators, remove every second object\n");
01038    {
01039       struct ao2_iterator ai;
01040       int x = 0;
01041 
01042       ai = ao2_iterator_init(c1, 0);
01043       while ( (obj = ao2_t_iterator_next(&ai,"test")) ) {
01044          ast_cli(a->fd, "iterator on <%s>\n", obj);
01045          if (x++ & 1)
01046             ao2_t_unlink(c1, obj,"test");
01047          ao2_t_ref(obj, -1,"test");
01048       }
01049       ast_cli(a->fd, "testing iterators again\n");
01050       ai = ao2_iterator_init(c1, 0);
01051       while ( (obj = ao2_t_iterator_next(&ai,"test")) ) {
01052          ast_cli(a->fd, "iterator on <%s>\n", obj);
01053          ao2_t_ref(obj, -1,"test");
01054       }
01055    }
01056    ast_cli(a->fd, "testing callbacks again\n");
01057    ao2_t_callback(c1, 0, print_cb, &a->fd,"test callback");
01058 
01059    ast_verbose("now you should see an error message:\n");
01060    ao2_t_ref(&i, -1, "");  /* i is not a valid object so we print an error here */
01061 
01062    ast_cli(a->fd, "destroy container\n");
01063    ao2_t_ref(c1, -1, "");  /* destroy container */
01064    handle_astobj2_stats(e, CLI_HANDLER, &fake_args);
01065    return CLI_SUCCESS;
01066 }
01067 
01068 static struct ast_cli_entry cli_astobj2[] = {
01069    AST_CLI_DEFINE(handle_astobj2_stats, "Print astobj2 statistics"),
01070    AST_CLI_DEFINE(handle_astobj2_test, "Test astobj2"),
01071 };
01072 #endif /* AO2_DEBUG */
01073 
01074 int astobj2_init(void)
01075 {
01076 #ifdef AO2_DEBUG
01077    ast_cli_register_multiple(cli_astobj2, ARRAY_LEN(cli_astobj2));
01078 #endif
01079 
01080    return 0;
01081 }

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