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      1 /*
      2  * Copyright (C) 2013 Google Inc. All rights reserved.
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions are
      6  * met:
      7  *
      8  *     * Redistributions of source code must retain the above copyright
      9  * notice, this list of conditions and the following disclaimer.
     10  *     * Redistributions in binary form must reproduce the above
     11  * copyright notice, this list of conditions and the following disclaimer
     12  * in the documentation and/or other materials provided with the
     13  * distribution.
     14  *     * Neither the name of Google Inc. nor the names of its
     15  * contributors may be used to endorse or promote products derived from
     16  * this software without specific prior written permission.
     17  *
     18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     19  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     21  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     22  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     23  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     24  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     28  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     29  */
     30 
     31 #include "config.h"
     32 #include "wtf/SpinLock.h"
     33 
     34 #include "wtf/Threading.h"
     35 #include <gtest/gtest.h>
     36 
     37 namespace {
     38 
     39 static const size_t bufferSize = 16;
     40 
     41 static int lock = 0;
     42 
     43 static void fillBuffer(volatile char* buffer, char fillPattern)
     44 {
     45     for (int i = 0; i < bufferSize; ++i)
     46         buffer[i] = fillPattern;
     47 }
     48 
     49 static void changeAndCheckBuffer(volatile char* buffer)
     50 {
     51     fillBuffer(buffer, '\0');
     52     int total = 0;
     53     for (int i = 0; i < bufferSize; ++i)
     54         total += buffer[i];
     55 
     56     EXPECT_EQ(0, total);
     57 
     58     // This will mess with the other thread's calculation if we accidentally get
     59     // concurrency.
     60     fillBuffer(buffer, '!');
     61 }
     62 
     63 static void threadMain(void* arg)
     64 {
     65     volatile char* buffer = reinterpret_cast<volatile char*>(arg);
     66     for (int i = 0; i < 500000; ++i) {
     67         spinLockLock(&lock);
     68         changeAndCheckBuffer(buffer);
     69         spinLockUnlock(&lock);
     70     }
     71 }
     72 
     73 TEST(WTF_SpinLock, Torture)
     74 {
     75     char sharedBuffer[bufferSize];
     76 
     77     ThreadIdentifier thread1 = createThread(threadMain, sharedBuffer, "thread1");
     78     ThreadIdentifier thread2 = createThread(threadMain, sharedBuffer, "thread2");
     79     EXPECT_NE(0, thread1);
     80     EXPECT_NE(0, thread2);
     81 
     82     int ret = waitForThreadCompletion(thread1);
     83     EXPECT_EQ(0, ret);
     84     ret = waitForThreadCompletion(thread2);
     85     EXPECT_EQ(0, ret);
     86 }
     87 
     88 } // namespace
     89