jenkins-promote-staging-trunk-libmemcached-5
[awesomized/libmemcached] / 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(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 pthread_mutex_destroy(&mutex);
93 pthread_cond_destroy(&cond);
94 delete [] server_pool;
95 if (_owns_master)
96 {
97 memcached_free(master);
98 }
99 }
100
101 void increment_version()
102 {
103 ++master->configure.version;
104 }
105
106 bool compare_version(const memcached_st *arg) const
107 {
108 return (arg->configure.version == version());
109 }
110
111 int32_t version() const
112 {
113 return master->configure.version;
114 }
115 };
116
117
118 /**
119 * Grow the connection pool by creating a connection structure and clone the
120 * original memcached handle.
121 */
122 static bool grow_pool(memcached_pool_st* pool)
123 {
124 assert(pool);
125
126 memcached_st *obj;
127 if (not (obj= memcached_clone(NULL, pool->master)))
128 {
129 return false;
130 }
131
132 pool->server_pool[++pool->firstfree]= obj;
133 pool->current_size++;
134 obj->configure.version= pool->version();
135
136 return true;
137 }
138
139 bool memcached_pool_st::init(uint32_t initial)
140 {
141 server_pool= new (std::nothrow) memcached_st *[size];
142 if (not server_pool)
143 return false;
144
145 /*
146 Try to create the initial size of the pool. An allocation failure at
147 this time is not fatal..
148 */
149 for (unsigned int x= 0; x < initial; ++x)
150 {
151 if (grow_pool(this) == false)
152 {
153 break;
154 }
155 }
156
157 return true;
158 }
159
160
161 static inline memcached_pool_st *_pool_create(memcached_st* master, uint32_t initial, uint32_t max)
162 {
163 if (initial == 0 or max == 0 or (initial > max))
164 {
165 return NULL;
166 }
167
168 memcached_pool_st *object= new (std::nothrow) memcached_pool_st(master, max);
169 if (object == NULL)
170 {
171 return NULL;
172 }
173
174 /*
175 Try to create the initial size of the pool. An allocation failure at
176 this time is not fatal..
177 */
178 if (not object->init(initial))
179 {
180 delete object;
181 return NULL;
182 }
183
184 return object;
185 }
186
187 memcached_pool_st *memcached_pool_create(memcached_st* master, uint32_t initial, uint32_t max)
188 {
189 return _pool_create(master, initial, max);
190 }
191
192 memcached_pool_st * memcached_pool(const char *option_string, size_t option_string_length)
193 {
194 memcached_st *memc= memcached(option_string, option_string_length);
195
196 if (memc == NULL)
197 {
198 return NULL;
199 }
200
201 memcached_pool_st *self= memcached_pool_create(memc, memc->configure.initial_pool_size, memc->configure.max_pool_size);
202 if (self == NULL)
203 {
204 memcached_free(memc);
205 return NULL;
206 }
207
208 self->_owns_master= true;
209
210 return self;
211 }
212
213 memcached_st* memcached_pool_destroy(memcached_pool_st* pool)
214 {
215 if (pool == NULL)
216 {
217 return NULL;
218 }
219
220 // Legacy that we return the original structure
221 memcached_st *ret= NULL;
222 if (pool->_owns_master)
223 { }
224 else
225 {
226 ret= pool->master;
227 }
228
229 delete pool;
230
231 return ret;
232 }
233
234 memcached_st* memcached_pool_st::fetch(memcached_return_t& rc)
235 {
236 static struct timespec relative_time= { 0, 0 };
237 return fetch(relative_time, rc);
238 }
239
240 memcached_st* memcached_pool_st::fetch(const struct timespec& relative_time, memcached_return_t& rc)
241 {
242 rc= MEMCACHED_SUCCESS;
243
244 int error;
245 if ((error= pthread_mutex_lock(&mutex)) != 0)
246 {
247 rc= MEMCACHED_IN_PROGRESS;
248 return NULL;
249 }
250
251 memcached_st *ret= NULL;
252 do
253 {
254 if (firstfree > -1)
255 {
256 ret= server_pool[firstfree--];
257 }
258 else if (current_size == size)
259 {
260 if (relative_time.tv_sec == 0 and relative_time.tv_nsec == 0)
261 {
262 error= pthread_mutex_unlock(&mutex);
263 rc= MEMCACHED_NOTFOUND;
264
265 return NULL;
266 }
267
268 struct timespec time_to_wait= {0, 0};
269 time_to_wait.tv_sec= time(NULL) +relative_time.tv_sec;
270 time_to_wait.tv_nsec= relative_time.tv_nsec;
271
272 int thread_ret;
273 if ((thread_ret= pthread_cond_timedwait(&cond, &mutex, &time_to_wait)) != 0)
274 {
275 int unlock_error;
276 if ((unlock_error= pthread_mutex_unlock(&mutex)) != 0)
277 {
278 }
279
280 if (thread_ret == ETIMEDOUT)
281 {
282 rc= MEMCACHED_TIMEOUT;
283 }
284 else
285 {
286 errno= thread_ret;
287 rc= MEMCACHED_ERRNO;
288 }
289
290 return NULL;
291 }
292 }
293 else if (grow_pool(this) == false)
294 {
295 int unlock_error;
296 if ((unlock_error= pthread_mutex_unlock(&mutex)) != 0)
297 {
298 }
299
300 return NULL;
301 }
302 } while (ret == NULL);
303
304 if ((error= pthread_mutex_unlock(&mutex)) != 0)
305 {
306 }
307
308 return ret;
309 }
310
311 bool memcached_pool_st::release(memcached_st *released, memcached_return_t& rc)
312 {
313 rc= MEMCACHED_SUCCESS;
314 if (released == NULL)
315 {
316 rc= MEMCACHED_INVALID_ARGUMENTS;
317 return false;
318 }
319
320 int error;
321 if ((error= pthread_mutex_lock(&mutex)))
322 {
323 rc= MEMCACHED_IN_PROGRESS;
324 return false;
325 }
326
327 /*
328 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.
329 */
330 if (compare_version(released) == false)
331 {
332 memcached_st *memc;
333 if ((memc= memcached_clone(NULL, master)))
334 {
335 memcached_free(released);
336 released= memc;
337 }
338 }
339
340 server_pool[++firstfree]= released;
341
342 if (firstfree == 0 and current_size == size)
343 {
344 /* we might have people waiting for a connection.. wake them up :-) */
345 if ((error= pthread_cond_broadcast(&cond)) != 0)
346 {
347 }
348 }
349
350 if ((error= pthread_mutex_unlock(&mutex)) != 0)
351 {
352 }
353
354 return true;
355 }
356
357 memcached_st* memcached_pool_fetch(memcached_pool_st* pool, struct timespec* relative_time, memcached_return_t* rc)
358 {
359 if (pool == NULL)
360 {
361 return NULL;
362 }
363
364 memcached_return_t unused;
365 if (rc == NULL)
366 {
367 rc= &unused;
368 }
369
370 if (relative_time == NULL)
371 {
372 return pool->fetch(*rc);
373 }
374
375 return pool->fetch(*relative_time, *rc);
376 }
377
378 memcached_st* memcached_pool_pop(memcached_pool_st* pool,
379 bool block,
380 memcached_return_t *rc)
381 {
382 if (pool == NULL)
383 {
384 return NULL;
385 }
386
387 memcached_return_t unused;
388 if (rc == NULL)
389 {
390 rc= &unused;
391 }
392
393 memcached_st *memc;
394 if (block)
395 {
396 memc= pool->fetch(pool->timeout(), *rc);
397 }
398 else
399 {
400 memc= pool->fetch(*rc);
401 }
402
403 return memc;
404 }
405
406 memcached_return_t memcached_pool_release(memcached_pool_st* pool, memcached_st *released)
407 {
408 if (pool == NULL)
409 {
410 return MEMCACHED_INVALID_ARGUMENTS;
411 }
412
413 memcached_return_t rc;
414
415 (void) pool->release(released, rc);
416
417 return rc;
418 }
419
420 memcached_return_t memcached_pool_push(memcached_pool_st* pool, memcached_st *released)
421 {
422 return memcached_pool_release(pool, released);
423 }
424
425
426 memcached_return_t memcached_pool_behavior_set(memcached_pool_st *pool,
427 memcached_behavior_t flag,
428 uint64_t data)
429 {
430 if (pool == NULL)
431 {
432 return MEMCACHED_INVALID_ARGUMENTS;
433 }
434
435 int error;
436 if ((error= pthread_mutex_lock(&pool->mutex)))
437 {
438 return MEMCACHED_IN_PROGRESS;
439 }
440
441 /* update the master */
442 memcached_return_t rc= memcached_behavior_set(pool->master, flag, data);
443 if (memcached_failed(rc))
444 {
445 if ((error= pthread_mutex_unlock(&pool->mutex)) != 0)
446 {
447 }
448 return rc;
449 }
450
451 pool->increment_version();
452 /* update the clones */
453 for (int xx= 0; xx <= pool->firstfree; ++xx)
454 {
455 if (memcached_success(memcached_behavior_set(pool->server_pool[xx], flag, data)))
456 {
457 pool->server_pool[xx]->configure.version= pool->version();
458 }
459 else
460 {
461 memcached_st *memc;
462 if ((memc= memcached_clone(NULL, pool->master)))
463 {
464 memcached_free(pool->server_pool[xx]);
465 pool->server_pool[xx]= memc;
466 /* I'm not sure what to do in this case.. this would happen
467 if we fail to push the server list inside the client..
468 I should add a testcase for this, but I believe the following
469 would work, except that you would add a hole in the pool list..
470 in theory you could end up with an empty pool....
471 */
472 }
473 }
474 }
475
476 if ((error= pthread_mutex_unlock(&pool->mutex)) != 0)
477 {
478 }
479
480 return rc;
481 }
482
483 memcached_return_t memcached_pool_behavior_get(memcached_pool_st *pool,
484 memcached_behavior_t flag,
485 uint64_t *value)
486 {
487 if (pool == NULL)
488 {
489 return MEMCACHED_INVALID_ARGUMENTS;
490 }
491
492 int error;
493 if ((error= pthread_mutex_lock(&pool->mutex)))
494 {
495 return MEMCACHED_IN_PROGRESS;
496 }
497
498 *value= memcached_behavior_get(pool->master, flag);
499
500 if ((error= pthread_mutex_unlock(&pool->mutex)) != 0)
501 {
502 }
503
504 return MEMCACHED_SUCCESS;
505 }