sync_8h-source.html

来自「一个功能强大的内存数据库源代码,c++编写,有详细的注释」· HTML 代码 · 共 1,178 行 · 第 1/4 页

00288 <font class="preprocessor">#ifdef NO_MMAP</font>
00289 <font class="preprocessor"></font>        ptr = <font class="keyword">new</font> T();
00290 <font class="preprocessor">#else</font>
00291 <font class="preprocessor"></font>        h = CreateFileMapping(INVALID_HANDLE_VALUE,
00292                               FASTDB_SECURITY_ATTRIBUTES, PAGE_READWRITE, 0, 
00293                               <font class="keyword">sizeof</font>(T), name);
00294         <font class="keywordflow">if</font> (h == NULL) { 
00295             <font class="keywordflow">return</font> <font class="keyword">false</font>;
00296         }
00297         ptr = (T*)MapViewOfFile(h, FILE_MAP_ALL_ACCESS, 0, 0, 0);
00298         <font class="keywordflow">if</font> (ptr == NULL) { 
00299             CloseHandle(h);
00300             <font class="keywordflow">return</font> <font class="keyword">false</font>;
00301         }
00302 <font class="preprocessor">#endif</font>
00303 <font class="preprocessor"></font>        <font class="keywordflow">return</font> <font class="keyword">true</font>;
00304     }
00305 
00306     T* get() { <font class="keywordflow">return</font> ptr; }
00307 
00308     <font class="keywordtype">void</font> close() { 
00309 <font class="preprocessor">#ifdef NO_MMAP</font>
00310 <font class="preprocessor"></font>        <font class="keyword">delete</font>[] ptr;
00311 <font class="preprocessor">#else</font>
00312 <font class="preprocessor"></font>        UnmapViewOfFile(ptr);
00313         CloseHandle(h);
00314 <font class="preprocessor">#endif</font>
00315 <font class="preprocessor"></font>    }
00316     <font class="keywordtype">void</font> erase() { 
00317         close();
00318     }
00319 };
00320 
00321 <font class="keyword">typedef</font> <font class="keywordtype">long</font> sharedsem_t;
00322 
00323 <font class="keyword">class </font>FASTDB_DLL_ENTRY dbGlobalCriticalSection { 
00324     HANDLE       event;
00325     sharedsem_t* count;
00326 
00327   <font class="keyword">public</font>:
00328     <font class="keywordtype">void</font> enter() { 
00329         <font class="keywordflow">if</font> (InterlockedDecrement(count) != 0) { 
00330             <font class="comment">// another process is in critical section</font>
00331             <font class="keywordtype">int</font> rc = WaitForSingleObject(event, INFINITE);
00332             assert (rc == WAIT_OBJECT_0);
00333         }
00334     }
00335 
00336     <font class="keywordtype">void</font> leave() { 
00337         <font class="keywordflow">if</font> (InterlockedIncrement(count) &lt;= 0) { 
00338             <font class="comment">// some other processes try to enter critical section</font>
00339             SetEvent(event);
00340         }
00341     }
00342 
00343     <font class="keywordtype">bool</font> open(<font class="keywordtype">char</font> <font class="keyword">const</font>* name, <font class="keywordtype">long</font>* count) { 
00344         this-&gt;count = count;
00345         event = OpenEvent(EVENT_ALL_ACCESS, FALSE, name);
00346         <font class="keywordflow">return</font> event != NULL;
00347     }
00348     <font class="keywordtype">bool</font> create(<font class="keywordtype">char</font> <font class="keyword">const</font>* name, <font class="keywordtype">long</font>* count) { 
00349         this-&gt;count = count;
00350         *count = 1;
00351         event = CreateEvent(FASTDB_SECURITY_ATTRIBUTES, <font class="keyword">false</font>, <font class="keyword">false</font>, name);
00352         <font class="keywordflow">return</font> event != NULL;
00353     }
00354     <font class="keywordtype">void</font> close() { 
00355         CloseHandle(event);
00356     }
00357     <font class="keywordtype">void</font> erase() { 
00358         close();
00359     }
00360 };
00361         
00362     
00363 <font class="preprocessor">#else // Unix</font>
00364 <font class="preprocessor"></font>
00365 <font class="preprocessor">#include &lt;unistd.h&gt;</font>
00366 <font class="preprocessor">#include &lt;string.h&gt;</font>
00367 <font class="preprocessor">#include &lt;fcntl.h&gt;</font>
00368 <font class="preprocessor">#include &lt;sys/time.h&gt;</font>
00369 <font class="preprocessor">#include &lt;sys/types.h&gt;</font>
00370 <font class="preprocessor">#include &lt;errno.h&gt;</font>
00371 
00372 <font class="preprocessor">#ifdef USE_POSIX_API</font>
00373 <font class="preprocessor"></font><font class="preprocessor">#include &lt;semaphore.h&gt;</font>
00374 <font class="preprocessor">#include &lt;sys/mman.h&gt;</font>
00375 <font class="preprocessor">#else</font>
00376 <font class="preprocessor"></font><font class="preprocessor">#include &lt;sys/ipc.h&gt;</font>
00377 <font class="preprocessor">#include &lt;sys/sem.h&gt;</font>
00378 <font class="preprocessor">#include &lt;sys/shm.h&gt;</font>
00379 <font class="preprocessor">#include &lt;sys/mman.h&gt;</font>
00380 <font class="preprocessor">#endif</font>
00381 <font class="preprocessor"></font>
00382 <font class="preprocessor">#define thread_proc</font>
00383 <font class="preprocessor"></font>
00384 <font class="preprocessor">#ifndef NO_PTHREADS</font>
00385 <font class="preprocessor"></font>
00386 <font class="preprocessor">#include &lt;pthread.h&gt;</font>
00387 
00388 <font class="keyword">class </font>dbMutex { 
00389     <font class="keyword">friend</font> <font class="keyword">class </font>dbLocalEvent;
00390     <font class="keyword">friend</font> <font class="keyword">class </font>dbLocalSemaphore;
00391     pthread_mutex_t cs;
00392   <font class="keyword">public</font>:
00393     dbMutex() { 
00394         pthread_mutex_init(&amp;cs, NULL);
00395     }
00396     ~dbMutex() { 
00397         pthread_mutex_destroy(&amp;cs);
00398     }
00399     <font class="keywordtype">void</font> lock() { 
00400         pthread_mutex_lock(&amp;cs);
00401     }
00402     <font class="keywordtype">void</font> unlock() { 
00403         pthread_mutex_unlock(&amp;cs);
00404     }
00405 };
00406 
00407 <font class="keyword">const</font> size_t dbThreadStackSize = 1024*1024;
00408 
00409 <font class="keyword">class </font>dbThread { 
00410     pthread_t thread;
00411   <font class="keyword">public</font>:
00412     <font class="keyword">typedef</font> void (thread_proc* thread_proc_t)(<font class="keywordtype">void</font>*);
00413     <font class="keywordtype">void</font> create(thread_proc_t f, <font class="keywordtype">void</font>* arg) {
00414         pthread_attr_t attr;
00415         pthread_attr_init(&amp;attr);
00416 <font class="preprocessor">#if !defined(__linux__)</font>
00417 <font class="preprocessor"></font>        pthread_attr_setstacksize(&amp;attr, dbThreadStackSize);
00418 <font class="preprocessor">#endif</font>
00419 <font class="preprocessor"></font><font class="preprocessor">#if defined(_AIX41)</font>
00420 <font class="preprocessor"></font>        <font class="comment">// At AIX 4.1, 4.2 threads are by default created detached</font>
00421         pthread_attr_setdetachstate(&amp;attr, PTHREAD_CREATE_UNDETACHED);
00422 <font class="preprocessor">#endif</font>
00423 <font class="preprocessor"></font>        pthread_create(&amp;thread, &amp;attr, (<font class="keywordtype">void</font>*(*)(<font class="keywordtype">void</font>*))f, arg);
00424         pthread_attr_destroy(&amp;attr);
00425     }
00426 
00427     <font class="keywordtype">void</font> join() { 
00428         <font class="keywordtype">void</font>* result;
00429         pthread_join(thread, &amp;result);
00430     }
00431     <font class="keywordtype">void</font> detach() { 
00432         pthread_detach(thread);
00433     }
00434 
00435     <font class="keyword">enum</font> ThreadPriority { 
00436         THR_PRI_LOW, 
00437         THR_PRI_HIGH
00438     };
00439     <font class="keywordtype">void</font> setPriority(ThreadPriority pri) { 
00440 <font class="preprocessor">#if defined(PRI_OTHER_MIN) &amp;&amp; defined(PRI_OTHER_MAX)</font>
00441 <font class="preprocessor"></font>        <font class="keyword">struct </font>sched_param sp;
00442         sp.gsched_priority = pri == THR_PRI_LOW ? PRI_OTHER_MIN : PRI_OTHER_MAX;
00443         pthread_setschedparam(thread, SCHED_OTHER, &amp;sp); 
00444 <font class="preprocessor">#endif</font>
00445 <font class="preprocessor"></font>    }
00446 
00447     <font class="keyword">static</font> <font class="keywordtype">int</font> numberOfProcessors();
00448 };
00449 
00450 
00451 <font class="keyword">class </font>dbLocalEvent { 
00452     pthread_cond_t   cond;
00453     <font class="keywordtype">int</font>              signaled;
00454   <font class="keyword">public</font>:
00455     <font class="keywordtype">void</font> wait(dbMutex&amp; mutex) { 
00456         <font class="keywordflow">while</font> (!signaled) { 
00457             pthread_cond_wait(&amp;cond, &amp;mutex.cs);
00458         }
00459     }
00460     <font class="keywordtype">bool</font> wait(dbMutex&amp; mutex, time_t timeout) {
00461         <font class="keywordflow">while</font> (!signaled) {
00462             <font class="keyword">struct </font>timespec abs_ts; 
00463 <font class="preprocessor">#ifdef PTHREAD_GET_EXPIRATION_NP</font>
00464 <font class="preprocessor"></font>            <font class="keyword">struct </font>timespec rel_ts; 
00465             rel_ts.tv_sec = timeout/1000; 
00466             rel_ts.tv_nsec = timeout%1000*1000000;
00467             pthread_get_expiration_np(&amp;rel_ts, &amp;abs_ts);
00468 <font class="preprocessor">#else</font>
00469 <font class="preprocessor"></font>            <font class="keyword">struct </font>timeval cur_tv;
00470             gettimeofday(&amp;cur_tv, NULL);
00471             abs_ts.tv_sec = cur_tv.tv_sec + timeout/1000; 
00472             abs_ts.tv_nsec = cur_tv.tv_usec*1000 + timeout%1000*1000000;
00473             <font class="keywordflow">if</font> (abs_ts.tv_nsec &gt; 1000000000) { 
00474                 abs_ts.tv_nsec -= 1000000000;
00475                 abs_ts.tv_sec += 1;
00476             }
00477 <font class="preprocessor">#endif</font>
00478 <font class="preprocessor"></font>            <font class="keywordtype">int</font> rc = pthread_cond_timedwait(&amp;cond, &amp;mutex.cs, &amp;abs_ts);
00479             <font class="keywordflow">if</font> (rc == ETIMEDOUT) { 
00480                 <font class="keywordflow">return</font> <font class="keyword">false</font>;
00481             }
00482         }
00483         <font class="keywordflow">return</font> <font class="keyword">true</font>;
00484     }
00485     <font class="keywordtype">void</font> signal() {
00486         signaled = <font class="keyword">true</font>;
00487         pthread_cond_broadcast(&amp;cond);
00488     }
00489     <font class="keywordtype">void</font> reset() {
00490         signaled = <font class="keyword">false</font>;
00491     }
00492     <font class="keywordtype">void</font> open(<font class="keywordtype">bool</font> initValue = <font class="keyword">false</font>) { 
00493         signaled = initValue;
00494         pthread_cond_init(&amp;cond, NULL);
00495     }
00496     <font class="keywordtype">void</font> close() {
00497         pthread_cond_destroy(&amp;cond);
00498     }
00499 };
00500 
00501 <font class="keyword">class </font>dbLocalSemaphore { 
00502     pthread_cond_t   cond;
00503     <font class="keywordtype">int</font>              count;
00504   <font class="keyword">public</font>:
00505     <font class="keywordtype">void</font> wait(dbMutex&amp; mutex) { 
00506         <font class="keywordflow">while</font> (count == 0) { 
00507             pthread_cond_wait(&amp;cond, &amp;mutex.cs);
00508         }
00509         count -= 1;
00510     }
00511     <font class="keywordtype">void</font> wait(dbMutex&amp; mutex, time_t timeout) {
00512         <font class="keywordflow">while</font> (count == 0) {
00513             <font class="keyword">struct </font>timespec abs_ts; 
00514 <font class="preprocessor">#ifdef PTHREAD_GET_EXPIRATION_NP</font>
00515 <font class="preprocessor"></font>            <font class="keyword">struct </font>timespec rel_ts; 
00516             rel_ts.tv_sec = timeout/1000; 
00517             rel_ts.tv_nsec = timeout%1000*1000000;
00518             pthread_get_expiration_np(&amp;rel_ts, &amp;abs_ts);
00519 <font class="preprocessor">#else</font>
00520 <font class="preprocessor"></font>            <font class="keyword">struct </font>timeval cur_tv;
00521             gettimeofday(&amp;cur_tv, NULL);
00522             abs_ts.tv_sec = cur_tv.tv_sec + timeout/1000; 
00523             abs_ts.tv_nsec = cur_tv.tv_usec*1000 + timeout%1000*1000000;
00524             <font class="keywordflow">if</font> (abs_ts.tv_nsec &gt; 1000000000) { 
00525                 abs_ts.tv_nsec -= 1000000000;
00526                 abs_ts.tv_sec += 1;
00527             }
00528 <font class="preprocessor">#endif</font>
00529 <font class="preprocessor"></font>            pthread_cond_timedwait(&amp;cond, &amp;mutex.cs, &amp;abs_ts);
00530         }
00531         count -= 1;
00532     }
00533      <font class="keywordtype">void</font> signal(<font class="keywordtype">unsigned</font> inc = 1) {
00534         count += inc;
00535         <font class="keywordflow">if</font> (inc &gt; 1) { 
00536             pthread_cond_broadcast(&amp;cond);
00537         } <font class="keywordflow">else</font> <font class="keywordflow">if</font> (inc == 1) { 
00538             pthread_cond_signal(&amp;cond);
00539         }
00540     }
00541     <font class="keywordtype">void</font> open(<font class="keywordtype">unsigned</font> initValue = 0) { 
00542         pthread_cond_init(&amp;cond, NULL);
00543         count = initValue;
00544     }
00545     <font class="keywordtype">void</font> close() {
00546         pthread_cond_destroy(&amp;cond);
00547     }
00548 };
00549 
00550 <font class="keyword">template</font>&lt;<font class="keyword">class</font> T&gt; 
00551 <font class="keyword">class </font>dbThreadContext { 
00552     pthread_key_t key;
00553   <font class="keyword">public</font>:
00554     T* get() { 
00555         <font class="keywordflow">return</font> (T*)pthread_getspecific(key);
00556     }
00557     <font class="keywordtype">void</font> set(T* value) { 
00558         pthread_setspecific(key, value);
00559     }
00560     dbThreadContext() { 
00561         pthread_key_create(&amp;key, NULL);
00562     }
00563     ~dbThreadContext() { 
00564         pthread_key_delete(key);
00565     }
00566 };
00567 
00568 <font class="keyword">class </font>dbProcessId { 
00569     <font class="keywordtype">int</font>       pid;
00570     pthread_t tid;
00571   <font class="keyword">public</font>:
00572     <font class="keywordtype">bool</font> operator != (dbProcessId <font class="keyword">const</font>&amp; other)<font class="keyword"> const </font>{ 
00573         <font class="keywordflow">return</font> pid != other.pid || tid != other.tid;
00574     }
00575 
00576     <font class="keywordtype">void</font> clear() { 
00577         pid = 0;
00578         tid = 0;
00579     }
00580 
00581     <font class="keyword">static</font> dbProcessId getCurrent() {
00582         dbProcessId curr;