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 #ifndef _ASTERISK_ASTOBJ2_H 00018 #define _ASTERISK_ASTOBJ2_H 00019 00020 #include "asterisk/compat.h" 00021 00022 /*! \file 00023 * \ref AstObj2 00024 * 00025 * \page AstObj2 Object Model implementing objects and containers. 00026 00027 This module implements an abstraction for objects (with locks and 00028 reference counts), and containers for these user-defined objects, 00029 also supporting locking, reference counting and callbacks. 00030 00031 The internal implementation of objects and containers is opaque to the user, 00032 so we can use different data structures as needs arise. 00033 00034 \section AstObj2_UsageObjects USAGE - OBJECTS 00035 00036 An ao2 object is a block of memory that the user code can access, 00037 and for which the system keeps track (with a bit of help from the 00038 programmer) of the number of references around. When an object has 00039 no more references (refcount == 0), it is destroyed, by first 00040 invoking whatever 'destructor' function the programmer specifies 00041 (it can be NULL if none is necessary), and then freeing the memory. 00042 This way objects can be shared without worrying who is in charge 00043 of freeing them. 00044 As an additional feature, ao2 objects are associated to individual 00045 locks. 00046 00047 Creating an object requires the size of the object and 00048 and a pointer to the destructor function: 00049 00050 struct foo *o; 00051 00052 o = ao2_alloc(sizeof(struct foo), my_destructor_fn); 00053 00054 The value returned points to the user-visible portion of the objects 00055 (user-data), but is also used as an identifier for all object-related 00056 operations such as refcount and lock manipulations. 00057 00058 On return from ao2_alloc(): 00059 00060 - the object has a refcount = 1; 00061 - the memory for the object is allocated dynamically and zeroed; 00062 - we cannot realloc() the object itself; 00063 - we cannot call free(o) to dispose of the object. Rather, we 00064 tell the system that we do not need the reference anymore: 00065 00066 ao2_ref(o, -1) 00067 00068 causing the destructor to be called (and then memory freed) when 00069 the refcount goes to 0. 00070 00071 - ao2_ref(o, +1) can be used to modify the refcount on the 00072 object in case we want to pass it around. 00073 00074 - ao2_lock(obj), ao2_unlock(obj), ao2_trylock(obj) can be used 00075 to manipulate the lock associated with the object. 00076 00077 00078 \section AstObj2_UsageContainers USAGE - CONTAINERS 00079 00080 An ao2 container is an abstract data structure where we can store 00081 ao2 objects, search them (hopefully in an efficient way), and iterate 00082 or apply a callback function to them. A container is just an ao2 object 00083 itself. 00084 00085 A container must first be allocated, specifying the initial 00086 parameters. At the moment, this is done as follows: 00087 00088 <b>Sample Usage:</b> 00089 \code 00090 00091 struct ao2_container *c; 00092 00093 c = ao2_container_alloc(MAX_BUCKETS, my_hash_fn, my_cmp_fn); 00094 \endcode 00095 00096 where 00097 00098 - MAX_BUCKETS is the number of buckets in the hash table, 00099 - my_hash_fn() is the (user-supplied) function that returns a 00100 hash key for the object (further reduced modulo MAX_BUCKETS 00101 by the container's code); 00102 - my_cmp_fn() is the default comparison function used when doing 00103 searches on the container, 00104 00105 A container knows little or nothing about the objects it stores, 00106 other than the fact that they have been created by ao2_alloc(). 00107 All knowledge of the (user-defined) internals of the objects 00108 is left to the (user-supplied) functions passed as arguments 00109 to ao2_container_alloc(). 00110 00111 If we want to insert an object in a container, we should 00112 initialize its fields -- especially, those used by my_hash_fn() -- 00113 to compute the bucket to use. 00114 Once done, we can link an object to a container with 00115 00116 ao2_link(c, o); 00117 00118 The function returns NULL in case of errors (and the object 00119 is not inserted in the container). Other values mean success 00120 (we are not supposed to use the value as a pointer to anything). 00121 Linking an object to a container increases its refcount by 1 00122 automatically. 00123 00124 \note While an object o is in a container, we expect that 00125 my_hash_fn(o) will always return the same value. The function 00126 does not lock the object to be computed, so modifications of 00127 those fields that affect the computation of the hash should 00128 be done by extracting the object from the container, and 00129 reinserting it after the change (this is not terribly expensive). 00130 00131 \note A container with a single buckets is effectively a linked 00132 list. However there is no ordering among elements. 00133 00134 - \ref AstObj2_Containers 00135 - \ref astobj2.h All documentation for functions and data structures 00136 00137 */ 00138 00139 /* 00140 \note DEBUGGING REF COUNTS BIBLE: 00141 An interface to help debug refcounting is provided 00142 in this package. It is dependent on the REF_DEBUG macro being 00143 defined in a source file, before the #include of astobj2.h, 00144 and in using variants of the normal ao2_xxxx functions 00145 that are named ao2_t_xxxx instead, with an extra argument, a string, 00146 that will be printed out into /tmp/refs when the refcount for an 00147 object is changed. 00148 00149 these ao2_t_xxxx variants are provided: 00150 00151 ao2_t_alloc(arg1, arg2, arg3) 00152 ao2_t_ref(arg1,arg2,arg3) 00153 ao2_t_container_alloc(arg1,arg2,arg3,arg4) 00154 ao2_t_link(arg1, arg2, arg3) 00155 ao2_t_unlink(arg1, arg2, arg3) 00156 ao2_t_callback(arg1,arg2,arg3,arg4,arg5) 00157 ao2_t_find(arg1,arg2,arg3,arg4) 00158 ao2_t_iterator_next(arg1, arg2) 00159 00160 If you study each argument list, you will see that these functions all have 00161 one extra argument that their ao2_xxx counterpart. The last argument in 00162 each case is supposed to be a string pointer, a "tag", that should contain 00163 enough of an explanation, that you can pair operations that increment the 00164 ref count, with operations that are meant to decrement the refcount. 00165 00166 Each of these calls will generate at least one line of output in /tmp/refs. 00167 These lines look like this: 00168 ... 00169 0x8756f00 =1 chan_sip.c:22240:load_module (allocate users) 00170 0x86e3408 =1 chan_sip.c:22241:load_module (allocate peers) 00171 0x86dd380 =1 chan_sip.c:22242:load_module (allocate peers_by_ip) 00172 0x822d020 =1 chan_sip.c:22243:load_module (allocate dialogs) 00173 0x8930fd8 =1 chan_sip.c:20025:build_peer (allocate a peer struct) 00174 0x8930fd8 +1 chan_sip.c:21467:reload_config (link peer into peer table) [@1] 00175 0x8930fd8 -1 chan_sip.c:2370:unref_peer (unref_peer: from reload_config) [@2] 00176 0x89318b0 =1 chan_sip.c:20025:build_peer (allocate a peer struct) 00177 0x89318b0 +1 chan_sip.c:21467:reload_config (link peer into peer table) [@1] 00178 0x89318b0 -1 chan_sip.c:2370:unref_peer (unref_peer: from reload_config) [@2] 00179 0x8930218 =1 chan_sip.c:20025:build_peer (allocate a peer struct) 00180 0x8930218 +1 chan_sip.c:21539:reload_config (link peer into peers table) [@1] 00181 0x868c040 -1 chan_sip.c:2424:dialog_unlink_all (unset the relatedpeer->call field in tandem with relatedpeer field itself) [@2] 00182 0x868c040 -1 chan_sip.c:2443:dialog_unlink_all (Let's unbump the count in the unlink so the poor pvt can disappear if it is time) [@1] 00183 0x868c040 **call destructor** chan_sip.c:2443:dialog_unlink_all (Let's unbump the count in the unlink so the poor pvt can disappear if it is time) 00184 0x8cc07e8 -1 chan_sip.c:2370:unref_peer (unsetting a dialog relatedpeer field in sip_destroy) [@3] 00185 0x8cc07e8 +1 chan_sip.c:3876:find_peer (ao2_find in peers table) [@2] 00186 0x8cc07e8 -1 chan_sip.c:2370:unref_peer (unref_peer, from sip_devicestate, release ref from find_peer) [@3] 00187 ... 00188 00189 The first column is the object address. 00190 The second column reflects how the operation affected the ref count 00191 for that object. Creation sets the ref count to 1 (=1). 00192 increment or decrement and amount are specified (-1/+1). 00193 The remainder of the line specifies where in the file the call was made, 00194 and the function name, and the tag supplied in the function call. 00195 00196 The **call destructor** is specified when the the destroy routine is 00197 run for an object. It does not affect the ref count, but is important 00198 in debugging, because it is possible to have the astobj2 system run it 00199 multiple times on the same object, commonly fatal to asterisk. 00200 00201 Sometimes you have some helper functions to do object ref/unref 00202 operations. Using these normally hides the place where these 00203 functions were called. To get the location where these functions 00204 were called to appear in /tmp/refs, you can do this sort of thing: 00205 00206 #ifdef REF_DEBUG 00207 #define dialog_ref(arg1,arg2) dialog_ref_debug((arg1),(arg2), __FILE__, __LINE__, __PRETTY_FUNCTION__) 00208 #define dialog_unref(arg1,arg2) dialog_unref_debug((arg1),(arg2), __FILE__, __LINE__, __PRETTY_FUNCTION__) 00209 static struct sip_pvt *dialog_ref_debug(struct sip_pvt *p, char *tag, char *file, int line, const char *func) 00210 { 00211 if (p) 00212 ao2_ref_debug(p, 1, tag, file, line, func); 00213 else 00214 ast_log(LOG_ERROR, "Attempt to Ref a null pointer\n"); 00215 return p; 00216 } 00217 00218 static struct sip_pvt *dialog_unref_debug(struct sip_pvt *p, char *tag, char *file, int line, const char *func) 00219 { 00220 if (p) 00221 ao2_ref_debug(p, -1, tag, file, line, func); 00222 return NULL; 00223 } 00224 #else 00225 static struct sip_pvt *dialog_ref(struct sip_pvt *p, char *tag) 00226 { 00227 if (p) 00228 ao2_ref(p, 1); 00229 else 00230 ast_log(LOG_ERROR, "Attempt to Ref a null pointer\n"); 00231 return p; 00232 } 00233 00234 static struct sip_pvt *dialog_unref(struct sip_pvt *p, char *tag) 00235 { 00236 if (p) 00237 ao2_ref(p, -1); 00238 return NULL; 00239 } 00240 #endif 00241 00242 In the above code, note that the "normal" helper funcs call ao2_ref() as 00243 normal, and the "helper" functions call ao2_ref_debug directly with the 00244 file, function, and line number info provided. You might find this 00245 well worth the effort to help track these function calls in the code. 00246 00247 To find out why objects are not destroyed (a common bug), you can 00248 edit the source file to use the ao2_t_* variants, add the #define REF_DEBUG 1 00249 before the #include "asterisk/astobj2.h" line, and add a descriptive 00250 tag to each call. Recompile, and run Asterisk, exit asterisk with 00251 "stop gracefully", which should result in every object being destroyed. 00252 Then, you can "sort -k 1 /tmp/refs > x1" to get a sorted list of 00253 all the objects, or you can use "util/refcounter" to scan the file 00254 for you and output any problems it finds. 00255 00256 The above may seem astronomically more work than it is worth to debug 00257 reference counts, which may be true in "simple" situations, but for 00258 more complex situations, it is easily worth 100 times this effort to 00259 help find problems. 00260 00261 To debug, pair all calls so that each call that increments the 00262 refcount is paired with a corresponding call that decrements the 00263 count for the same reason. Hopefully, you will be left with one 00264 or more unpaired calls. This is where you start your search! 00265 00266 For instance, here is an example of this for a dialog object in 00267 chan_sip, that was not getting destroyed, after I moved the lines around 00268 to pair operations: 00269 00270 0x83787a0 =1 chan_sip.c:5733:sip_alloc (allocate a dialog(pvt) struct) 00271 0x83787a0 -1 chan_sip.c:19173:sip_poke_peer (unref dialog at end of sip_poke_peer, obtained from sip_alloc, just before it goes out of scope) [@4] 00272 00273 0x83787a0 +1 chan_sip.c:5854:sip_alloc (link pvt into dialogs table) [@1] 00274 0x83787a0 -1 chan_sip.c:19150:sip_poke_peer (About to change the callid -- remove the old name) [@3] 00275 0x83787a0 +1 chan_sip.c:19152:sip_poke_peer (Linking in under new name) [@2] 00276 0x83787a0 -1 chan_sip.c:2399:dialog_unlink_all (unlinking dialog via ao2_unlink) [@5] 00277 00278 0x83787a0 +1 chan_sip.c:19130:sip_poke_peer (copy sip alloc from p to peer->call) [@2] 00279 00280 00281 0x83787a0 +1 chan_sip.c:2996:__sip_reliable_xmit (__sip_reliable_xmit: setting pkt->owner) [@3] 00282 0x83787a0 -1 chan_sip.c:2425:dialog_unlink_all (remove all current packets in this dialog, and the pointer to the dialog too as part of __sip_destroy) [@4] 00283 00284 0x83787a0 +1 chan_sip.c:22356:unload_module (iterate thru dialogs) [@4] 00285 0x83787a0 -1 chan_sip.c:22359:unload_module (toss dialog ptr from iterator_next) [@5] 00286 00287 00288 0x83787a0 +1 chan_sip.c:22373:unload_module (iterate thru dialogs) [@3] 00289 0x83787a0 -1 chan_sip.c:22375:unload_module (throw away iterator result) [@2] 00290 00291 0x83787a0 +1 chan_sip.c:2397:dialog_unlink_all (Let's bump the count in the unlink so it doesn't accidentally become dead before we are done) [@4] 00292 0x83787a0 -1 chan_sip.c:2436:dialog_unlink_all (Let's unbump the count in the unlink so the poor pvt can disappear if it is time) [@3] 00293 00294 As you can see, only one unbalanced operation is in the list, a ref count increment when 00295 the peer->call was set, but no corresponding decrement was made... 00296 00297 Hopefully this helps you narrow your search and find those bugs. 00298 00299 THE ART OF REFERENCE COUNTING 00300 (by Steve Murphy) 00301 SOME TIPS for complicated code, and ref counting: 00302 00303 1. Theoretically, passing a refcounted object pointer into a function 00304 call is an act of copying the reference, and could be refcounted. 00305 But, upon examination, this sort of refcounting will explode the amount 00306 of code you have to enter, and for no tangible benefit, beyond 00307 creating more possible failure points/bugs. It will even 00308 complicate your code and make debugging harder, slow down your program 00309 doing useless increments and decrements of the ref counts. 00310 00311 2. It is better to track places where a ref counted pointer 00312 is copied into a structure or stored. Make sure to decrement the refcount 00313 of any previous pointer that might have been there, if setting 00314 this field might erase a previous pointer. ao2_find and iterate_next 00315 internally increment the ref count when they return a pointer, so 00316 you need to decrement the count before the pointer goes out of scope. 00317 00318 3. Any time you decrement a ref count, it may be possible that the 00319 object will be destroyed (freed) immediately by that call. If you 00320 are destroying a series of fields in a refcounted object, and 00321 any of the unref calls might possibly result in immediate destruction, 00322 you can first increment the count to prevent such behavior, then 00323 after the last test, decrement the pointer to allow the object 00324 to be destroyed, if the refcount would be zero. 00325 00326 Example: 00327 00328 dialog_ref(dialog, "Let's bump the count in the unlink so it doesn't accidentally become dead before we are done"); 00329 00330 ao2_t_unlink(dialogs, dialog, "unlinking dialog via ao2_unlink"); 00331 00332 *//* Unlink us from the owner (channel) if we have one *//* 00333 if (dialog->owner) { 00334 if (lockowner) 00335 ast_channel_lock(dialog->owner); 00336 ast_debug(1, "Detaching from channel %s\n", dialog->owner->name); 00337 dialog->owner->tech_pvt = dialog_unref(dialog->owner->tech_pvt, "resetting channel dialog ptr in unlink_all"); 00338 if (lockowner) 00339 ast_channel_unlock(dialog->owner); 00340 } 00341 if (dialog->registry) { 00342 if (dialog->registry->call == dialog) 00343 dialog->registry->call = dialog_unref(dialog->registry->call, "nulling out the registry's call dialog field in unlink_all"); 00344 dialog->registry = registry_unref(dialog->registry, "delete dialog->registry"); 00345 } 00346 ... 00347 dialog_unref(dialog, "Let's unbump the count in the unlink so the poor pvt can disappear if it is time"); 00348 00349 In the above code, the ao2_t_unlink could end up destroying the dialog 00350 object; if this happens, then the subsequent usages of the dialog 00351 pointer could result in a core dump. So, we 'bump' the 00352 count upwards before beginning, and then decrementing the count when 00353 we are finished. This is analogous to 'locking' or 'protecting' operations 00354 for a short while. 00355 00356 4. One of the most insidious problems I've run into when converting 00357 code to do ref counted automatic destruction, is in the destruction 00358 routines. Where a "destroy" routine had previously been called to 00359 get rid of an object in non-refcounted code, the new regime demands 00360 that you tear that "destroy" routine into two pieces, one that will 00361 tear down the links and 'unref' them, and the other to actually free 00362 and reset fields. A destroy routine that does any reference deletion 00363 for its own object, will never be called. Another insidious problem 00364 occurs in mutually referenced structures. As an example, a dialog contains 00365 a pointer to a peer, and a peer contains a pointer to a dialog. Watch 00366 out that the destruction of one doesn't depend on the destruction of the 00367 other, as in this case a dependency loop will result in neither being 00368 destroyed! 00369 00370 Given the above, you should be ready to do a good job! 00371 00372 murf 00373 00374 */ 00375 00376 00377 00378 /*! \brief 00379 * Typedef for an object destructor. This is called just before freeing 00380 * the memory for the object. It is passed a pointer to the user-defined 00381 * data of the object. 00382 */ 00383 typedef void (*ao2_destructor_fn)(void *); 00384 00385 00386 /*! \brief 00387 * Allocate and initialize an object. 00388 * 00389 * \param data_size The sizeof() of the user-defined structure. 00390 * \param destructor_fn The destructor function (can be NULL) 00391 * \param debug_msg 00392 * \return A pointer to user-data. 00393 * 00394 * Allocates a struct astobj2 with sufficient space for the 00395 * user-defined structure. 00396 * \note 00397 * - storage is zeroed; XXX maybe we want a flag to enable/disable this. 00398 * - the refcount of the object just created is 1 00399 * - the returned pointer cannot be free()'d or realloc()'ed; 00400 * rather, we just call ao2_ref(o, -1); 00401 * 00402 * @{ 00403 */ 00404 00405 #if defined(REF_DEBUG) 00406 00407 #define ao2_t_alloc(data_size, destructor_fn, debug_msg) _ao2_alloc_debug((data_size), (destructor_fn), (debug_msg), __FILE__, __LINE__, __PRETTY_FUNCTION__, 1) 00408 #define ao2_alloc(data_size, destructor_fn) _ao2_alloc_debug((data_size), (destructor_fn), "", __FILE__, __LINE__, __PRETTY_FUNCTION__, 1) 00409 00410 #elif defined(__AST_DEBUG_MALLOC) 00411 00412 #define ao2_t_alloc(data_size, destructor_fn, debug_msg) _ao2_alloc_debug((data_size), (destructor_fn), (debug_msg), __FILE__, __LINE__, __PRETTY_FUNCTION__, 0) 00413 #define ao2_alloc(data_size, destructor_fn) _ao2_alloc_debug((data_size), (destructor_fn), "", __FILE__, __LINE__, __PRETTY_FUNCTION__, 0) 00414 00415 #else 00416 00417 #define ao2_t_alloc(data_size, destructor_fn, debug_msg) _ao2_alloc((data_size), (destructor_fn)) 00418 #define ao2_alloc(data_size, destructor_fn) _ao2_alloc((data_size), (destructor_fn)) 00419 00420 #endif 00421 00422 void *_ao2_alloc_debug(const size_t data_size, ao2_destructor_fn destructor_fn, char *tag, 00423 const char *file, int line, const char *funcname, int ref_debug); 00424 void *_ao2_alloc(const size_t data_size, ao2_destructor_fn destructor_fn); 00425 00426 /*! @} */ 00427 00428 /*! \brief 00429 * Reference/unreference an object and return the old refcount. 00430 * 00431 * \param o A pointer to the object 00432 * \param delta Value to add to the reference counter. 00433 * \return The value of the reference counter before the operation. 00434 * 00435 * Increase/decrease the reference counter according 00436 * the value of delta. 00437 * 00438 * If the refcount goes to zero, the object is destroyed. 00439 * 00440 * \note The object must not be locked by the caller of this function, as 00441 * it is invalid to try to unlock it after releasing the reference. 00442 * 00443 * \note if we know the pointer to an object, it is because we 00444 * have a reference count to it, so the only case when the object 00445 * can go away is when we release our reference, and it is 00446 * the last one in existence. 00447 * 00448 * @{ 00449 */ 00450 00451 #ifdef REF_DEBUG 00452 00453 #define ao2_t_ref(o,delta,tag) _ao2_ref_debug((o), (delta), (tag), __FILE__, __LINE__, __PRETTY_FUNCTION__) 00454 #define ao2_ref(o,delta) _ao2_ref_debug((o), (delta), "", __FILE__, __LINE__, __PRETTY_FUNCTION__) 00455 00456 #else 00457 00458 #define ao2_t_ref(o,delta,tag) _ao2_ref((o), (delta)) 00459 #define ao2_ref(o,delta) _ao2_ref((o), (delta)) 00460 00461 #endif 00462 00463 int _ao2_ref_debug(void *o, int delta, char *tag, char *file, int line, const char *funcname); 00464 int _ao2_ref(void *o, int delta); 00465 /*! @} */ 00466 00467 /*! @} */ 00468 00469 /*! \brief 00470 * Lock an object. 00471 * 00472 * \param a A pointer to the object we want to lock. 00473 * \return 0 on success, other values on error. 00474 */ 00475 int ao2_lock(void *a); 00476 int _ao2_lock(void *a, const char *file, const char *func, int line, const char *var); 00477 #ifdef DEBUG_THREADS 00478 #define ao2_lock(a) _ao2_lock(a, __FILE__, __PRETTY_FUNCTION__, __LINE__, #a) 00479 #endif 00480 00481 /*! \brief 00482 * Unlock an object. 00483 * 00484 * \param a A pointer to the object we want unlock. 00485 * \return 0 on success, other values on error. 00486 */ 00487 int ao2_unlock(void *a); 00488 int _ao2_unlock(void *a, const char *file, const char *func, int line, const char *var); 00489 #ifdef DEBUG_THREADS 00490 #define ao2_unlock(a) _ao2_unlock(a, __FILE__, __PRETTY_FUNCTION__, __LINE__, #a) 00491 #endif 00492 00493 /*! \brief 00494 * Try locking-- (don't block if fail) 00495 * 00496 * \param a A pointer to the object we want to lock. 00497 * \return 0 on success, other values on error. 00498 */ 00499 int ao2_trylock(void *a); 00500 int _ao2_trylock(void *a, const char *file, const char *func, int line, const char *var); 00501 #ifdef DEBUG_THREADS 00502 #define ao2_trylock(a) _ao2_trylock(a, __FILE__, __PRETTY_FUNCTION__, __LINE__, #a) 00503 #endif 00504 00505 /*! 00506 * \brief Return the lock address of an object 00507 * 00508 * \param[in] obj A pointer to the object we want. 00509 * \return the address of the lock, else NULL. 00510 * 00511 * This function comes in handy mainly for debugging locking 00512 * situations, where the locking trace code reports the 00513 * lock address, this allows you to correlate against 00514 * object address, to match objects to reported locks. 00515 * 00516 * \since 1.6.1 00517 */ 00518 void *ao2_object_get_lockaddr(void *obj); 00519 00520 /*! 00521 \page AstObj2_Containers AstObj2 Containers 00522 00523 Containers are data structures meant to store several objects, 00524 and perform various operations on them. 00525 Internally, objects are stored in lists, hash tables or other 00526 data structures depending on the needs. 00527 00528 \note NOTA BENE: at the moment the only container we support is the 00529 hash table and its degenerate form, the list. 00530 00531 Operations on container include: 00532 00533 - c = \b ao2_container_alloc(size, hash_fn, cmp_fn) 00534 allocate a container with desired size and default compare 00535 and hash function 00536 -The compare function returns an int, which 00537 can be 0 for not found, CMP_STOP to stop end a traversal, 00538 or CMP_MATCH if they are equal 00539 -The hash function returns an int. The hash function 00540 takes two argument, the object pointer and a flags field, 00541 00542 - \b ao2_find(c, arg, flags) 00543 returns zero or more element matching a given criteria 00544 (specified as arg). 'c' is the container pointer. Flags 00545 can be: 00546 OBJ_UNLINK - to remove the object, once found, from the container. 00547 OBJ_NODATA - don't return the object if found (no ref count change) 00548 OBJ_MULTIPLE - don't stop at first match (not fully implemented) 00549 OBJ_POINTER - if set, 'arg' is an object pointer, and a hashtable 00550 search will be done. If not, a traversal is done. 00551 00552 - \b ao2_callback(c, flags, fn, arg) 00553 apply fn(obj, arg) to all objects in the container. 00554 Similar to find. fn() can tell when to stop, and 00555 do anything with the object including unlinking it. 00556 - c is the container; 00557 - flags can be 00558 OBJ_UNLINK - to remove the object, once found, from the container. 00559 OBJ_NODATA - don't return the object if found (no ref count change) 00560 OBJ_MULTIPLE - don't stop at first match (not fully implemented) 00561 OBJ_POINTER - if set, 'arg' is an object pointer, and a hashtable 00562 search will be done. If not, a traversal is done through 00563 all the hashtable 'buckets'.. 00564 - fn is a func that returns int, and takes 3 args: 00565 (void *obj, void *arg, int flags); 00566 obj is an object 00567 arg is the same as arg passed into ao2_callback 00568 flags is the same as flags passed into ao2_callback 00569 fn returns: 00570 0: no match, keep going 00571 CMP_STOP: stop search, no match 00572 CMP_MATCH: This object is matched. 00573 00574 Note that the entire operation is run with the container 00575 locked, so noone else can change its content while we work on it. 00576 However, we pay this with the fact that doing 00577 anything blocking in the callback keeps the container 00578 blocked. 00579 The mechanism is very flexible because the callback function fn() 00580 can do basically anything e.g. counting, deleting records, etc. 00581 possibly using arg to store the results. 00582 00583 - \b iterate on a container 00584 this is done with the following sequence 00585 00586 \code 00587 00588 struct ao2_container *c = ... // our container 00589 struct ao2_iterator i; 00590 void *o; 00591 00592 i = ao2_iterator_init(c, flags); 00593 00594 while ((o = ao2_iterator_next(&i))) { 00595 ... do something on o ... 00596 ao2_ref(o, -1); 00597 } 00598 00599 ao2_iterator_destroy(&i); 00600 \endcode 00601 00602 The difference with the callback is that the control 00603 on how to iterate is left to us. 00604 00605 - \b ao2_ref(c, -1) 00606 dropping a reference to a container destroys it, very simple! 00607 00608 Containers are ao2 objects themselves, and this is why their 00609 implementation is simple too. 00610 00611 Before declaring containers, we need to declare the types of the 00612 arguments passed to the constructor - in turn, this requires 00613 to define callback and hash functions and their arguments. 00614 00615 - \ref AstObj2 00616 - \ref astobj2.h 00617 */ 00618 00619 /*! \brief 00620 * Type of a generic callback function 00621 * \param obj pointer to the (user-defined part) of an object. 00622 * \param arg callback argument from ao2_callback() 00623 * \param flags flags from ao2_callback() 00624 * 00625 * The return values are a combination of enum _cb_results. 00626 * Callback functions are used to search or manipulate objects in a container. 00627 */ 00628 typedef int (ao2_callback_fn)(void *obj, void *arg, int flags); 00629 00630 /*! \brief 00631 * Type of a generic callback function 00632 * \param obj pointer to the (user-defined part) of an object. 00633 * \param arg callback argument from ao2_callback() 00634 * \param data arbitrary data from ao2_callback() 00635 * \param flags flags from ao2_callback() 00636 * 00637 * The return values are a combination of enum _cb_results. 00638 * Callback functions are used to search or manipulate objects in a container. 00639 */ 00640 typedef int (ao2_callback_data_fn)(void *obj, void *arg, void *data, int flags); 00641 00642 /*! \brief a very common callback is one that matches by address. */ 00643 ao2_callback_fn ao2_match_by_addr; 00644 00645 /*! \brief 00646 * A callback function will return a combination of CMP_MATCH and CMP_STOP. 00647 * The latter will terminate the search in a container. 00648 */ 00649 enum _cb_results { 00650 CMP_MATCH = 0x1, /*!< the object matches the request */ 00651 CMP_STOP = 0x2, /*!< stop the search now */ 00652 }; 00653 00654 /*! \brief 00655 * Flags passed to ao2_callback() and ao2_hash_fn() to modify its behaviour. 00656 */ 00657 enum search_flags { 00658 /*! Unlink the object for which the callback function 00659 * returned CMP_MATCH . This is the only way to extract 00660 * objects from a container. */ 00661 OBJ_UNLINK = (1 << 0), 00662 /*! On match, don't return the object hence do not increase 00663 * its refcount. */ 00664 OBJ_NODATA = (1 << 1), 00665 /*! Don't stop at the first match in ao2_callback() 00666 * \note This is not fully implemented. Using OBJ_MULTIME with OBJ_NODATA 00667 * is perfectly fine. The part that is not implemented is the case where 00668 * multiple objects should be returned by ao2_callback(). 00669 */ 00670 OBJ_MULTIPLE = (1 << 2), 00671 /*! obj is an object of the same type as the one being searched for, 00672 * so use the object's hash function for optimized searching. 00673 * The search function is unaffected (i.e. use the one passed as 00674 * argument, or match_by_addr if none specified). */ 00675 OBJ_POINTER = (1 << 3), 00676 /*! 00677 * \brief Continue if a match is not found in the hashed out bucket 00678 * 00679 * This flag is to be used in combination with OBJ_POINTER. This tells 00680 * the ao2_callback() core to keep searching through the rest of the 00681 * buckets if a match is not found in the starting bucket defined by 00682 * the hash value on the argument. 00683 */ 00684 OBJ_CONTINUE = (1 << 4), 00685 }; 00686 00687 /*! 00688 * Type of a generic function to generate a hash value from an object. 00689 * flags is ignored at the moment. Eventually, it will include the 00690 * value of OBJ_POINTER passed to ao2_callback(). 00691 */ 00692 typedef int (ao2_hash_fn)(const void *obj, const int flags); 00693 00694 /*! \name Object Containers 00695 * Here start declarations of containers. 00696 */ 00697 /*@{ */ 00698 struct ao2_container; 00699 00700 /*! \brief 00701 * Allocate and initialize a container 00702 * with the desired number of buckets. 00703 * 00704 * We allocate space for a struct astobj_container, struct container 00705 * and the buckets[] array. 00706 * 00707 * \param n_buckets Number of buckets for hash 00708 * \param hash_fn Pointer to a function computing a hash value. 00709 * \param cmp_fn Pointer to a function comparating key-value 00710 * with a string. (can be NULL) 00711 * \return A pointer to a struct container. 00712 * 00713 * destructor is set implicitly. 00714 */ 00715 00716 #if defined(REF_DEBUG) 00717 00718 #define ao2_t_container_alloc(arg1,arg2,arg3,arg4) _ao2_container_alloc_debug((arg1), (arg2), (arg3), (arg4), __FILE__, __LINE__, __PRETTY_FUNCTION__, 1) 00719 #define ao2_container_alloc(arg1,arg2,arg3) _ao2_container_alloc_debug((arg1), (arg2), (arg3), "", __FILE__, __LINE__, __PRETTY_FUNCTION__, 1) 00720 00721 #elif defined(__AST_DEBUG_MALLOC) 00722 00723 #define ao2_t_container_alloc(arg1,arg2,arg3,arg4) _ao2_container_alloc_debug((arg1), (arg2), (arg3), (arg4), __FILE__, __LINE__, __PRETTY_FUNCTION__, 0) 00724 #define ao2_container_alloc(arg1,arg2,arg3) _ao2_container_alloc_debug((arg1), (arg2), (arg3), "", __FILE__, __LINE__, __PRETTY_FUNCTION__, 0) 00725 00726 #else 00727 00728 #define ao2_t_container_alloc(arg1,arg2,arg3,arg4) _ao2_container_alloc((arg1), (arg2), (arg3)) 00729 #define ao2_container_alloc(arg1,arg2,arg3) _ao2_container_alloc((arg1), (arg2), (arg3)) 00730 00731 #endif 00732 00733 struct ao2_container *_ao2_container_alloc(const unsigned int n_buckets, 00734 ao2_hash_fn *hash_fn, ao2_callback_fn *cmp_fn); 00735 struct ao2_container *_ao2_container_alloc_debug(const unsigned int n_buckets, 00736 ao2_hash_fn *hash_fn, ao2_callback_fn *cmp_fn, 00737 char *tag, char *file, int line, const char *funcname, 00738 int ref_debug); 00739 00740 /*! \brief 00741 * Returns the number of elements in a container. 00742 */ 00743 int ao2_container_count(struct ao2_container *c); 00744 00745 /*@} */ 00746 00747 /*! \name Object Management 00748 * Here we have functions to manage objects. 00749 * 00750 * We can use the functions below on any kind of 00751 * object defined by the user. 00752 */ 00753 /*@{ */ 00754 00755 /*! 00756 * \brief Add an object to a container. 00757 * 00758 * \param c the container to operate on. 00759 * \param newobj the object to be added. 00760 * 00761 * \retval NULL on errors 00762 * \retval newobj on success. 00763 * 00764 * This function inserts an object in a container according its key. 00765 * 00766 * \note Remember to set the key before calling this function. 00767 * 00768 * \note This function automatically increases the reference count to account 00769 * for the reference that the container now holds to the object. 00770 */ 00771 #ifdef REF_DEBUG 00772 00773 #define ao2_t_link(arg1, arg2, arg3) _ao2_link_debug((arg1), (arg2), (arg3), __FILE__, __LINE__, __PRETTY_FUNCTION__) 00774 #define ao2_link(arg1, arg2) _ao2_link_debug((arg1), (arg2), "", __FILE__, __LINE__, __PRETTY_FUNCTION__) 00775 00776 #else 00777 00778 #define ao2_t_link(arg1, arg2, arg3) _ao2_link((arg1), (arg2)) 00779 #define ao2_link(arg1, arg2) _ao2_link((arg1), (arg2)) 00780 00781 #endif 00782 00783 void *_ao2_link_debug(struct ao2_container *c, void *new_obj, char *tag, char *file, int line, const char *funcname); 00784 void *_ao2_link(struct ao2_container *c, void *newobj); 00785 00786 /*! 00787 * \brief Remove an object from a container 00788 * 00789 * \param c the container 00790 * \param obj the object to unlink 00791 * 00792 * \retval NULL, always 00793 * 00794 * \note The object requested to be unlinked must be valid. However, if it turns 00795 * out that it is not in the container, this function is still safe to 00796 * be called. 00797 * 00798 * \note If the object gets unlinked from the container, the container's 00799 * reference to the object will be automatically released. (The 00800 * refcount will be decremented). 00801 */ 00802 #ifdef REF_DEBUG 00803 00804 #define ao2_t_unlink(arg1, arg2, arg3) _ao2_unlink_debug((arg1), (arg2), (arg3), __FILE__, __LINE__, __PRETTY_FUNCTION__) 00805 #define ao2_unlink(arg1, arg2) _ao2_unlink_debug((arg1), (arg2), "", __FILE__, __LINE__, __PRETTY_FUNCTION__) 00806 00807 #else 00808 00809 #define ao2_t_unlink(arg1, arg2, arg3) _ao2_unlink((arg1), (arg2)) 00810 #define ao2_unlink(arg1, arg2) _ao2_unlink((arg1), (arg2)) 00811 00812 #endif 00813 00814 void *_ao2_unlink_debug(struct ao2_container *c, void *obj, char *tag, char *file, int line, const char *funcname); 00815 void *_ao2_unlink(struct ao2_container *c, void *obj); 00816 00817 00818 /*! \brief Used as return value if the flag OBJ_MULTIPLE is set */ 00819 struct ao2_list { 00820 struct ao2_list *next; 00821 void *obj; /* pointer to the user portion of the object */ 00822 }; 00823 00824 /*@} */ 00825 00826 /*! \brief 00827 * ao2_callback() is a generic function that applies cb_fn() to all objects 00828 * in a container, as described below. 00829 * 00830 * \param c A pointer to the container to operate on. 00831 * \param flags A set of flags specifying the operation to perform, 00832 partially used by the container code, but also passed to 00833 the callback. 00834 - If OBJ_NODATA is set, ao2_callback will return NULL. No refcounts 00835 of any of the traversed objects will be incremented. 00836 On the converse, if it is NOT set (the default), The ref count 00837 of each object for which CMP_MATCH was set will be incremented, 00838 and you will have no way of knowing which those are, until 00839 the multiple-object-return functionality is implemented. 00840 - If OBJ_POINTER is set, the traversed items will be restricted 00841 to the objects in the bucket that the object key hashes to. 00842 * \param cb_fn A function pointer, that will be called on all 00843 objects, to see if they match. This function returns CMP_MATCH 00844 if the object is matches the criteria; CMP_STOP if the traversal 00845 should immediately stop, or both (via bitwise ORing), if you find a 00846 match and want to end the traversal, and 0 if the object is not a match, 00847 but the traversal should continue. This is the function that is applied 00848 to each object traversed. It's arguments are: 00849 (void *obj, void *arg, int flags), where: 00850 obj is an object 00851 arg is the same as arg passed into ao2_callback 00852 flags is the same as flags passed into ao2_callback (flags are 00853 also used by ao2_callback). 00854 * \param arg passed to the callback. 00855 * \return A pointer to the object found/marked, 00856 * a pointer to a list of objects matching comparison function, 00857 * NULL if not found. 00858 * 00859 * If the function returns any objects, their refcount is incremented, 00860 * and the caller is in charge of decrementing them once done. 00861 * Also, in case of multiple values returned, the list used 00862 * to store the objects must be freed by the caller. 00863 * 00864 * Typically, ao2_callback() is used for two purposes: 00865 * - to perform some action (including removal from the container) on one 00866 * or more objects; in this case, cb_fn() can modify the object itself, 00867 * and to perform deletion should set CMP_MATCH on the matching objects, 00868 * and have OBJ_UNLINK set in flags. 00869 * - to look for a specific object in a container; in this case, cb_fn() 00870 * should not modify the object, but just return a combination of 00871 * CMP_MATCH and CMP_STOP on the desired object. 00872 * Other usages are also possible, of course. 00873 00874 * This function searches through a container and performs operations 00875 * on objects according on flags passed. 00876 * XXX describe better 00877 * The comparison is done calling the compare function set implicitly. 00878 * The p pointer can be a pointer to an object or to a key, 00879 * we can say this looking at flags value. 00880 * If p points to an object we will search for the object pointed 00881 * by this value, otherwise we serch for a key value. 00882 * If the key is not uniq we only find the first matching valued. 00883 * If we use the OBJ_MARK flags, we mark all the objects matching 00884 * the condition. 00885 * 00886 * The use of flags argument is the follow: 00887 * 00888 * OBJ_UNLINK unlinks the object found 00889 * OBJ_NODATA on match, do return an object 00890 * Callbacks use OBJ_NODATA as a default 00891 * functions such as find() do 00892 * OBJ_MULTIPLE return multiple matches 00893 * Default for _find() is no. 00894 * to a key (not yet supported) 00895 * OBJ_POINTER the pointer is an object pointer 00896 * 00897 * In case we return a list, the callee must take care to destroy 00898 * that list when no longer used. 00899 * 00900 * \note When the returned object is no longer in use, ao2_ref() should 00901 * be used to free the additional reference possibly created by this function. 00902 * 00903 * @{ 00904 */ 00905 #ifdef REF_DEBUG 00906 00907 #define ao2_t_callback(c,flags,cb_fn,arg,tag) _ao2_callback_debug((c), (flags), (cb_fn), (arg), (tag), __FILE__, __LINE__, __PRETTY_FUNCTION__) 00908 #define ao2_callback(c,flags,cb_fn,arg) _ao2_callback_debug((c), (flags), (cb_fn), (arg), "", __FILE__, __LINE__, __PRETTY_FUNCTION__) 00909 00910 #else 00911 00912 #define ao2_t_callback(c,flags,cb_fn,arg,tag) _ao2_callback((c), (flags), (cb_fn), (arg)) 00913 #define ao2_callback(c,flags,cb_fn,arg) _ao2_callback((c), (flags), (cb_fn), (arg)) 00914 00915 #endif 00916 00917 void *_ao2_callback_debug(struct ao2_container *c, enum search_flags flags, 00918 ao2_callback_fn *cb_fn, void *arg, char *tag, 00919 char *file, int line, const char *funcname); 00920 void *_ao2_callback(struct ao2_container *c, 00921 enum search_flags flags, 00922 ao2_callback_fn *cb_fn, void *arg); 00923 /*! @} */ 00924 00925 /*! \brief 00926 * ao2_callback_data() is a generic function that applies cb_fn() to all objects 00927 * in a container. It is functionally identical to ao2_callback() except that 00928 * instead of taking an ao2_callback_fn *, it takes an ao2_callback_data_fn *, and 00929 * allows the caller to pass in arbitrary data. 00930 * 00931 * This call would be used instead of ao2_callback() when the caller needs to pass 00932 * OBJ_POINTER as part of the flags argument (which in turn requires passing in a 00933 * prototype ao2 object for 'arg') and also needs access to other non-global data 00934 * to complete it's comparison or task. 00935 * 00936 * See the documentation for ao2_callback() for argument descriptions. 00937 * 00938 * \see ao2_callback() 00939 */ 00940 #ifdef REF_DEBUG 00941 #define ao2_t_callback_data(arg1,arg2,arg3,arg4,arg5,arg6) _ao2_callback_data_debug((arg1), (arg2), (arg3), (arg4), (arg5), (arg6), __FILE__, __LINE__, __PRETTY_FUNCTION__) 00942 #define ao2_callback_data(arg1,arg2,arg3,arg4,arg5) _ao2_callback_data_debug((arg1), (arg2), (arg3), (arg4), (arg5), "", __FILE__, __LINE__, __PRETTY_FUNCTION__) 00943 #else 00944 #define ao2_t_callback_data(arg1,arg2,arg3,arg4,arg5,arg6) _ao2_callback_data((arg1), (arg2), (arg3), (arg4), (arg5)) 00945 #define ao2_callback_data(arg1,arg2,arg3,arg4,arg5) _ao2_callback_data((arg1), (arg2), (arg3), (arg4), (arg5)) 00946 #endif 00947 void *_ao2_callback_data_debug(struct ao2_container *c, enum search_flags flags, 00948 ao2_callback_data_fn *cb_fn, void *arg, void *data, char *tag, 00949 char *file, int line, const char *funcname); 00950 void *_ao2_callback_data(struct ao2_container *c, 00951 enum search_flags flags, 00952 ao2_callback_data_fn *cb_fn, void *arg, void *data); 00953 00954 /*! ao2_find() is a short hand for ao2_callback(c, flags, c->cmp_fn, arg) 00955 * XXX possibly change order of arguments ? 00956 */ 00957 #ifdef REF_DEBUG 00958 00959 #define ao2_t_find(arg1,arg2,arg3,arg4) _ao2_find_debug((arg1), (arg2), (arg3), (arg4), __FILE__, __LINE__, __PRETTY_FUNCTION__) 00960 #define ao2_find(arg1,arg2,arg3) _ao2_find_debug((arg1), (arg2), (arg3), "", __FILE__, __LINE__, __PRETTY_FUNCTION__) 00961 00962 #else 00963 00964 #define ao2_t_find(arg1,arg2,arg3,arg4) _ao2_find((arg1), (arg2), (arg3)) 00965 #define ao2_find(arg1,arg2,arg3) _ao2_find((arg1), (arg2), (arg3)) 00966 00967 #endif 00968 00969 void *_ao2_find_debug(struct ao2_container *c, void *arg, enum search_flags flags, char *tag, char *file, int line, const char *funcname); 00970 void *_ao2_find(struct ao2_container *c, void *arg, enum search_flags flags); 00971 00972 /*! \brief 00973 * 00974 * 00975 * When we need to walk through a container, we use an 00976 * ao2_iterator to keep track of the current position. 00977 * 00978 * Because the navigation is typically done without holding the 00979 * lock on the container across the loop, objects can be inserted or deleted 00980 * or moved while we work. As a consequence, there is no guarantee that 00981 * we manage to touch all the elements in the container, and it is possible 00982 * that we touch the same object multiple times. 00983 * 00984 * However, within the current hash table container, the following is true: 00985 * - It is not possible to miss an object in the container while iterating 00986 * unless it gets added after the iteration begins and is added to a bucket 00987 * that is before the one the current object is in. In this case, even if 00988 * you locked the container around the entire iteration loop, you still would 00989 * not see this object, because it would still be waiting on the container 00990 * lock so that it can be added. 00991 * - It would be extremely rare to see an object twice. The only way this can 00992 * happen is if an object got unlinked from the container and added again 00993 * during the same iteration. Furthermore, when the object gets added back, 00994 * it has to be in the current or later bucket for it to be seen again. 00995 * 00996 * An iterator must be first initialized with ao2_iterator_init(), 00997 * then we can use o = ao2_iterator_next() to move from one 00998 * element to the next. Remember that the object returned by 00999 * ao2_iterator_next() has its refcount incremented, 01000 * and the reference must be explicitly released when done with it. 01001 * 01002 * In addition, ao2_iterator_init() will hold a reference to the container 01003 * being iterated, which will be freed when ao2_iterator_destroy() is called 01004 * to free up the resources used by the iterator (if any). 01005 * 01006 * Example: 01007 * 01008 * \code 01009 * 01010 * struct ao2_container *c = ... // the container we want to iterate on 01011 * struct ao2_iterator i; 01012 * struct my_obj *o; 01013 * 01014 * i = ao2_iterator_init(c, flags); 01015 * 01016 * while ((o = ao2_iterator_next(&i))) { 01017 * ... do something on o ... 01018 * ao2_ref(o, -1); 01019 * } 01020 * 01021 * ao2_iterator_destroy(&i); 01022 * 01023 * \endcode 01024 * 01025 */ 01026 01027 /*! \brief 01028 * The astobj2 iterator 01029 * 01030 * \note You are not supposed to know the internals of an iterator! 01031 * We would like the iterator to be opaque, unfortunately 01032 * its size needs to be known if we want to store it around 01033 * without too much trouble. 01034 * Anyways... 01035 * The iterator has a pointer to the container, and a flags 01036 * field specifying various things e.g. whether the container 01037 * should be locked or not while navigating on it. 01038 * The iterator "points" to the current object, which is identified 01039 * by three values: 01040 * 01041 * - a bucket number; 01042 * - the object_id, which is also the container version number 01043 * when the object was inserted. This identifies the object 01044 * uniquely, however reaching the desired object requires 01045 * scanning a list. 01046 * - a pointer, and a container version when we saved the pointer. 01047 * If the container has not changed its version number, then we 01048 * can safely follow the pointer to reach the object in constant time. 01049 * 01050 * Details are in the implementation of ao2_iterator_next() 01051 * A freshly-initialized iterator has bucket=0, version=0. 01052 */ 01053 struct ao2_iterator { 01054 /*! the container */ 01055 struct ao2_container *c; 01056 /*! operation flags */ 01057 int flags; 01058 /*! current bucket */ 01059 int bucket; 01060 /*! container version */ 01061 unsigned int c_version; 01062 /*! pointer to the current object */ 01063 void *obj; 01064 /*! container version when the object was created */ 01065 unsigned int version; 01066 }; 01067 01068 /*! Flags that can be passed to ao2_iterator_init() to modify the behavior 01069 * of the iterator. 01070 */ 01071 enum ao2_iterator_flags { 01072 /*! Prevents ao2_iterator_next() from locking the container 01073 * while retrieving the next object from it. 01074 */ 01075 AO2_ITERATOR_DONTLOCK = (1 << 0), 01076 }; 01077 01078 /*! 01079 * \brief Create an iterator for a container 01080 * 01081 * \param c the container 01082 * \param flags one or more flags from ao2_iterator_flags 01083 * 01084 * \retval the constructed iterator 01085 * 01086 * \note This function does \b not take a pointer to an iterator; 01087 * rather, it returns an iterator structure that should be 01088 * assigned to (overwriting) an existing iterator structure 01089 * allocated on the stack or on the heap. 01090 * 01091 * This function will take a reference on the container being iterated. 01092 * 01093 */ 01094 struct ao2_iterator ao2_iterator_init(struct ao2_container *c, int flags); 01095 01096 /*! 01097 * \brief Destroy a container iterator 01098 * 01099 * \param i the iterator to destroy 01100 * 01101 * \retval none 01102 * 01103 * This function will release the container reference held by the iterator 01104 * and any other resources it may be holding. 01105 * 01106 */ 01107 void ao2_iterator_destroy(struct ao2_iterator *i); 01108 01109 #ifdef REF_DEBUG 01110 01111 #define ao2_t_iterator_next(arg1, arg2) _ao2_iterator_next_debug((arg1), (arg2), __FILE__, __LINE__, __PRETTY_FUNCTION__) 01112 #define ao2_iterator_next(arg1) _ao2_iterator_next_debug((arg1), "", __FILE__, __LINE__, __PRETTY_FUNCTION__) 01113 01114 #else 01115 01116 #define ao2_t_iterator_next(arg1, arg2) _ao2_iterator_next((arg1)) 01117 #define ao2_iterator_next(arg1) _ao2_iterator_next((arg1)) 01118 01119 #endif 01120 01121 void *_ao2_iterator_next_debug(struct ao2_iterator *a, char *tag, char *file, int line, const char *funcname); 01122 void *_ao2_iterator_next(struct ao2_iterator *a); 01123 01124 /* extra functions */ 01125 void ao2_bt(void); /* backtrace */ 01126 01127 #endif /* _ASTERISK_ASTOBJ2_H */