git.m6w6.name Git - awesomized/libmemcached/blob - libmemcachedutil/pool.cc

   1 /*  vim:expandtab:shiftwidth=2:tabstop=2:smarttab:
   2  *
   3  *  Libmemcached library
   4  *
   5  *  Copyright (C) 2011 Data Differential, http://datadifferential.com/
   6  *  Copyright (C) 2010 Brian Aker All rights reserved.
   7  *
   8  *  Redistribution and use in source and binary forms, with or without
   9  *  modification, are permitted provided that the following conditions are
  10  *  met:
  11  *
  12  *      * Redistributions of source code must retain the above copyright
  13  *  notice, this list of conditions and the following disclaimer.
  14  *
  15  *      * Redistributions in binary form must reproduce the above
  16  *  copyright notice, this list of conditions and the following disclaimer
  17  *  in the documentation and/or other materials provided with the
  18  *  distribution.
  19  *
  20  *      * The names of its contributors may not be used to endorse or
  21  *  promote products derived from this software without specific prior
  22  *  written permission.
  23  *
  24  *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  25  *  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  26  *  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  27  *  A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  28  *  OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  29  *  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  30  *  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  31  *  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  32  *  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  33  *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  34  *  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  35  *
  36  */
  37
  38
  39 #include <libmemcachedutil/common.h>
  40
  41 #include <cassert>
  42 #include <cerrno>
  43 #include <pthread.h>
  44 #include <memory>
  45
  46 struct memcached_pool_st
  47 {
  48   pthread_mutex_t mutex;
  49   pthread_cond_t cond;
  50   memcached_st *master;
  51   memcached_st **server_pool;
  52   int firstfree;
  53   const uint32_t size;
  54   uint32_t current_size;
  55   bool _owns_master;
  56   struct timespec _timeout;
  57
  58   memcached_pool_st(memcached_st *master_arg, size_t max_arg) :
  59     master(master_arg),
  60     server_pool(NULL),
  61     firstfree(-1),
  62     size(uint32_t(max_arg)),
  63     current_size(0),
  64     _owns_master(false)
  65   {
  66     pthread_mutex_init(&mutex, NULL);
  67     pthread_cond_init(&cond, NULL);
  68     _timeout.tv_sec= 5;
  69     _timeout.tv_nsec= 0;
  70   }
  71
  72   const struct timespec& timeout() const
  73   {
  74     return _timeout;
  75   }
  76
  77   bool release(memcached_st*, memcached_return_t& rc);
  78
  79   memcached_st *fetch(memcached_return_t& rc);
  80   memcached_st *fetch(const struct timespec&, memcached_return_t& rc);
  81
  82   bool init(uint32_t initial);
  83
  84   ~memcached_pool_st()
  85   {
  86     for (int x= 0; x <= firstfree; ++x)
  87     {
  88       memcached_free(server_pool[x]);
  89       server_pool[x]= NULL;
  90     }
  91
  92     int error;
  93     if ((error= pthread_mutex_destroy(&mutex)) != 0)
  94     {
  95       assert_vmsg(error != 0, "pthread_mutex_destroy() %s(%d)", strerror(error), error);
  96     }
  97
  98     if ((error= pthread_cond_destroy(&cond)) != 0)
  99     {
 100       assert_vmsg(error != 0, "pthread_cond_destroy() %s", strerror(error));
 101     }
 102
 103     delete [] server_pool;
 104     if (_owns_master)
 105     {
 106       memcached_free(master);
 107     }
 108   }
 109
 110   void increment_version()
 111   {
 112     ++master->configure.version;
 113   }
 114
 115   bool compare_version(const memcached_st *arg) const
 116   {
 117     return (arg->configure.version == version());
 118   }
 119
 120   int32_t version() const
 121   {
 122     return master->configure.version;
 123   }
 124 };
 125
 126
 127 /**
 128  * Grow the connection pool by creating a connection structure and clone the
 129  * original memcached handle.
 130  */
 131 static bool grow_pool(memcached_pool_st* pool)
 132 {
 133   assert(pool);
 134
 135   memcached_st *obj;
 136   if (not (obj= memcached_clone(NULL, pool->master)))
 137   {
 138     return false;
 139   }
 140
 141   pool->server_pool[++pool->firstfree]= obj;
 142   pool->current_size++;
 143   obj->configure.version= pool->version();
 144
 145   return true;
 146 }
 147
 148 bool memcached_pool_st::init(uint32_t initial)
 149 {
 150   server_pool= new (std::nothrow) memcached_st *[size];
 151   if (server_pool == NULL)
 152   {
 153     return false;
 154   }
 155
 156   /*
 157     Try to create the initial size of the pool. An allocation failure at
 158     this time is not fatal..
 159   */
 160   for (unsigned int x= 0; x < initial; ++x)
 161   {
 162     if (grow_pool(this) == false)
 163     {
 164       break;
 165     }
 166   }
 167
 168   return true;
 169 }
 170
 171
 172 static inline memcached_pool_st *_pool_create(memcached_st* master, uint32_t initial, uint32_t max)
 173 {
 174   if (initial == 0 or max == 0 or (initial > max))
 175   {
 176     return NULL;
 177   }
 178
 179   memcached_pool_st *object= new (std::nothrow) memcached_pool_st(master, max);
 180   if (object == NULL)
 181   {
 182     return NULL;
 183   }
 184
 185   /*
 186     Try to create the initial size of the pool. An allocation failure at
 187     this time is not fatal..
 188   */
 189   if (not object->init(initial))
 190   {
 191     delete object;
 192     return NULL;
 193   }
 194
 195   return object;
 196 }
 197
 198 memcached_pool_st *memcached_pool_create(memcached_st* master, uint32_t initial, uint32_t max)
 199 {
 200   return _pool_create(master, initial, max);
 201 }
 202
 203 memcached_pool_st * memcached_pool(const char *option_string, size_t option_string_length)
 204 {
 205   memcached_st *memc= memcached(option_string, option_string_length);
 206
 207   if (memc == NULL)
 208   {
 209     return NULL;
 210   }
 211
 212   memcached_pool_st *self= memcached_pool_create(memc, memc->configure.initial_pool_size, memc->configure.max_pool_size);
 213   if (self == NULL)
 214   {
 215     memcached_free(memc);
 216     return NULL;
 217   }
 218
 219   self->_owns_master= true;
 220
 221   return self;
 222 }
 223
 224 memcached_st*  memcached_pool_destroy(memcached_pool_st* pool)
 225 {
 226   if (pool == NULL)
 227   {
 228     return NULL;
 229   }
 230
 231   // Legacy that we return the original structure
 232   memcached_st *ret= NULL;
 233   if (pool->_owns_master)
 234   { }
 235   else
 236   {
 237     ret= pool->master;
 238   }
 239
 240   delete pool;
 241
 242   return ret;
 243 }
 244
 245 memcached_st* memcached_pool_st::fetch(memcached_return_t& rc)
 246 {
 247   static struct timespec relative_time= { 0, 0 };
 248   return fetch(relative_time, rc);
 249 }
 250
 251 memcached_st* memcached_pool_st::fetch(const struct timespec& relative_time, memcached_return_t& rc)
 252 {
 253   rc= MEMCACHED_SUCCESS;
 254
 255   int error;
 256   if ((error= pthread_mutex_lock(&mutex)) != 0)
 257   {
 258     rc= MEMCACHED_IN_PROGRESS;
 259     return NULL;
 260   }
 261
 262   memcached_st *ret= NULL;
 263   do
 264   {
 265     if (firstfree > -1)
 266     {
 267       ret= server_pool[firstfree--];
 268     }
 269     else if (current_size == size)
 270     {
 271       if (relative_time.tv_sec == 0 and relative_time.tv_nsec == 0)
 272       {
 273         error= pthread_mutex_unlock(&mutex);
 274         rc= MEMCACHED_NOTFOUND;
 275
 276         return NULL;
 277       }
 278
 279       struct timespec time_to_wait= {0, 0};
 280       time_to_wait.tv_sec= time(NULL) +relative_time.tv_sec;
 281       time_to_wait.tv_nsec= relative_time.tv_nsec;
 282
 283       int thread_ret;
 284       if ((thread_ret= pthread_cond_timedwait(&cond, &mutex, &time_to_wait)) != 0)
 285       {
 286         int unlock_error;
 287         if ((unlock_error= pthread_mutex_unlock(&mutex)) != 0)
 288         {
 289           assert_vmsg(error != 0, "pthread_mutex_unlock() %s", strerror(error));
 290         }
 291
 292         if (thread_ret == ETIMEDOUT)
 293         {
 294           rc= MEMCACHED_TIMEOUT;
 295         }
 296         else
 297         {
 298           errno= thread_ret;
 299           rc= MEMCACHED_ERRNO;
 300         }
 301
 302         return NULL;
 303       }
 304     }
 305     else if (grow_pool(this) == false)
 306     {
 307       int unlock_error;
 308       if ((unlock_error= pthread_mutex_unlock(&mutex)) != 0)
 309       {
 310         assert_vmsg(error != 0, "pthread_mutex_unlock() %s", strerror(error));
 311       }
 312
 313       return NULL;
 314     }
 315   } while (ret == NULL);
 316
 317   if ((error= pthread_mutex_unlock(&mutex)) != 0)
 318   {
 319     assert_vmsg(error != 0, "pthread_mutex_unlock() %s", strerror(error));
 320   }
 321
 322   return ret;
 323 }
 324
 325 bool memcached_pool_st::release(memcached_st *released, memcached_return_t& rc)
 326 {
 327   rc= MEMCACHED_SUCCESS;
 328   if (released == NULL)
 329   {
 330     rc= MEMCACHED_INVALID_ARGUMENTS;
 331     return false;
 332   }
 333
 334   int error;
 335   if ((error= pthread_mutex_lock(&mutex)))
 336   {
 337     rc= MEMCACHED_IN_PROGRESS;
 338     return false;
 339   }
 340
 341   /*
 342     Someone updated the behavior on the object, so we clone a new memcached_st with the new settings. If we fail to clone, we keep the old one around.
 343   */
 344   if (compare_version(released) == false)
 345   {
 346     memcached_st *memc;
 347     if ((memc= memcached_clone(NULL, master)))
 348     {
 349       memcached_free(released);
 350       released= memc;
 351     }
 352   }
 353
 354   server_pool[++firstfree]= released;
 355
 356   if (firstfree == 0 and current_size == size)
 357   {
 358     /* we might have people waiting for a connection.. wake them up :-) */
 359     if ((error= pthread_cond_broadcast(&cond)) != 0)
 360     {
 361       assert_vmsg(error != 0, "pthread_cond_broadcast() %s", strerror(error));
 362     }
 363   }
 364
 365   if ((error= pthread_mutex_unlock(&mutex)) != 0)
 366   {
 367   }
 368
 369   return true;
 370 }
 371
 372 memcached_st* memcached_pool_fetch(memcached_pool_st* pool, struct timespec* relative_time, memcached_return_t* rc)
 373 {
 374   if (pool == NULL)
 375   {
 376     return NULL;
 377   }
 378
 379   memcached_return_t unused;
 380   if (rc == NULL)
 381   {
 382     rc= &unused;
 383   }
 384
 385   if (relative_time == NULL)
 386   {
 387     return pool->fetch(*rc);
 388   }
 389
 390   return pool->fetch(*relative_time, *rc);
 391 }
 392
 393 memcached_st* memcached_pool_pop(memcached_pool_st* pool,
 394                                  bool block,
 395                                  memcached_return_t *rc)
 396 {
 397   if (pool == NULL)
 398   {
 399     return NULL;
 400   }
 401
 402   memcached_return_t unused;
 403   if (rc == NULL)
 404   {
 405     rc= &unused;
 406   }
 407
 408   memcached_st *memc;
 409   if (block)
 410   {
 411     memc= pool->fetch(pool->timeout(), *rc);
 412   }
 413   else
 414   {
 415     memc= pool->fetch(*rc);
 416   }
 417
 418   return memc;
 419 }
 420
 421 memcached_return_t memcached_pool_release(memcached_pool_st* pool, memcached_st *released)
 422 {
 423   if (pool == NULL)
 424   {
 425     return MEMCACHED_INVALID_ARGUMENTS;
 426   }
 427
 428   memcached_return_t rc;
 429
 430   (void) pool->release(released, rc);
 431
 432   return rc;
 433 }
 434
 435 memcached_return_t memcached_pool_push(memcached_pool_st* pool, memcached_st *released)
 436 {
 437   return memcached_pool_release(pool, released);
 438 }
 439
 440
 441 memcached_return_t memcached_pool_behavior_set(memcached_pool_st *pool,
 442                                                memcached_behavior_t flag,
 443                                                uint64_t data)
 444 {
 445   if (pool == NULL)
 446   {
 447     return MEMCACHED_INVALID_ARGUMENTS;
 448   }
 449
 450   int error;
 451   if ((error= pthread_mutex_lock(&pool->mutex)))
 452   {
 453     return MEMCACHED_IN_PROGRESS;
 454   }
 455
 456   /* update the master */
 457   memcached_return_t rc= memcached_behavior_set(pool->master, flag, data);
 458   if (memcached_failed(rc))
 459   {
 460     if ((error= pthread_mutex_unlock(&pool->mutex)) != 0)
 461     {
 462       assert_vmsg(error != 0, "pthread_mutex_unlock() %s", strerror(error));
 463     }
 464     return rc;
 465   }
 466
 467   pool->increment_version();
 468   /* update the clones */
 469   for (int xx= 0; xx <= pool->firstfree; ++xx)
 470   {
 471     if (memcached_success(memcached_behavior_set(pool->server_pool[xx], flag, data)))
 472     {
 473       pool->server_pool[xx]->configure.version= pool->version();
 474     }
 475     else
 476     {
 477       memcached_st *memc;
 478       if ((memc= memcached_clone(NULL, pool->master)))
 479       {
 480         memcached_free(pool->server_pool[xx]);
 481         pool->server_pool[xx]= memc;
 482         /* I'm not sure what to do in this case.. this would happen
 483           if we fail to push the server list inside the client..
 484           I should add a testcase for this, but I believe the following
 485           would work, except that you would add a hole in the pool list..
 486           in theory you could end up with an empty pool....
 487         */
 488       }
 489     }
 490   }
 491
 492   if ((error= pthread_mutex_unlock(&pool->mutex)) != 0)
 493   {
 494     assert_vmsg(error != 0, "pthread_mutex_unlock() %s", strerror(error));
 495   }
 496
 497   return rc;
 498 }
 499
 500 memcached_return_t memcached_pool_behavior_get(memcached_pool_st *pool,
 501                                                memcached_behavior_t flag,
 502                                                uint64_t *value)
 503 {
 504   if (pool == NULL)
 505   {
 506     return MEMCACHED_INVALID_ARGUMENTS;
 507   }
 508
 509   int error;
 510   if ((error= pthread_mutex_lock(&pool->mutex)))
 511   {
 512     return MEMCACHED_IN_PROGRESS;
 513   }
 514
 515   *value= memcached_behavior_get(pool->master, flag);
 516
 517   if ((error= pthread_mutex_unlock(&pool->mutex)) != 0)
 518   {
 519     assert_vmsg(error != 0, "pthread_mutex_unlock() %s", strerror(error));
 520   }
 521
 522   return MEMCACHED_SUCCESS;
 523 }