[2/3] kernel32/tests: Add a SRWLock test to simulate a typical usecase

[Sebastian Lackner]

This test has the purpose to verify that the SRWLock also behaves
correctly in a "real world scenario" where multiple threads have access
to the same shared data and periodically exclusive access is required.

Please note that no sleeps are required to ensure that the exclusive
access can happen - as soon as AcquireSRWLockExclusive is called no
further shared lock requests will be accepted until the exclusive access
is over.

---
 dlls/kernel32/tests/sync.c |   85
++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 85 insertions(+)
-------------- next part --------------
>From f03e92f96e840b6d4fb683457583032305418c38 Mon Sep 17 00:00:00 2001
From: Sebastian Lackner <sebastian at fds-team.de>
Date: Sat, 11 Jan 2014 02:23:12 +0100
Subject: kernel32/tests: Add a SRWLock test to simulate a typical usecase

---
 dlls/kernel32/tests/sync.c |   85 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 85 insertions(+)

diff --git a/dlls/kernel32/tests/sync.c b/dlls/kernel32/tests/sync.c
index 79e045d..e5d1353 100644
--- a/dlls/kernel32/tests/sync.c
+++ b/dlls/kernel32/tests/sync.c
@@ -1919,6 +1919,90 @@ static void test_srwlock_base(void)
     }
 }
 
+static SRWLOCK srwlock_example;
+static LONG srwlock_protected_value = 0;
+static LONG srwlock_example_errors = 0, srwlock_inside = 0, srwlock_cnt = 0;
+static BOOL srwlock_stop = FALSE;
+
+static DWORD WINAPI srwlock_example_thread(LPVOID x) {
+    DWORD *cnt = (DWORD*)x;
+    LONG old;
+
+    while (!srwlock_stop)
+    {
+
+        /* periodically request exclusive access */
+        if (InterlockedIncrement(&srwlock_cnt) % 13 == 0)
+        {
+            pAcquireSRWLockExclusive(&srwlock_example);
+            if (InterlockedIncrement(&srwlock_inside) != 1)
+                InterlockedIncrement(&srwlock_example_errors);
+
+            InterlockedIncrement(&srwlock_protected_value);
+            Sleep(1);
+
+            if (InterlockedDecrement(&srwlock_inside) != 0)
+                InterlockedIncrement(&srwlock_example_errors);
+            pReleaseSRWLockExclusive(&srwlock_example);
+        }
+
+        /* request shared access */
+        pAcquireSRWLockShared(&srwlock_example);
+        InterlockedIncrement(&srwlock_inside);
+        old = srwlock_protected_value;
+
+        (*cnt)++;
+        Sleep(1);
+
+        if (old != srwlock_protected_value)
+            InterlockedIncrement(&srwlock_example_errors);
+        InterlockedDecrement(&srwlock_inside);
+        pReleaseSRWLockShared(&srwlock_example);
+    }
+
+    return 0;
+}
+
+static void test_srwlock_example(void)
+{
+    HANDLE h1, h2, h3;
+    DWORD dummy;
+    DWORD cnt1, cnt2, cnt3;
+
+    if (!pInitializeSRWLock) {
+        /* function is not yet in XP, only in newer Windows */
+        win_skip("no srw lock support.\n");
+        return;
+    }
+
+    pInitializeSRWLock(&srwlock_example);
+
+    cnt1 = cnt2 = cnt3 = 0;
+
+    h1 = CreateThread(NULL, 0, srwlock_example_thread, &cnt1, 0, &dummy);
+    h2 = CreateThread(NULL, 0, srwlock_example_thread, &cnt2, 0, &dummy);
+    h3 = CreateThread(NULL, 0, srwlock_example_thread, &cnt3, 0, &dummy);
+
+    /* limit run to 1 second. */
+    Sleep(1000);
+
+    /* tear down start */
+    srwlock_stop = TRUE;
+
+    WaitForSingleObject(h1, 1000);
+    WaitForSingleObject(h2, 1000);
+    WaitForSingleObject(h3, 1000);
+
+    ok(!srwlock_inside, "threads didn't terminate properly, srwlock_inside is %d.\n", srwlock_inside);
+
+    todo_wine
+    ok(!srwlock_example_errors, "errors occured while running SRWLock example test (number of errors: %d)\n",
+            srwlock_example_errors);
+
+    trace("number of shared accesses per thread are c1 %d, c2 %d, c3 %d\n", cnt1, cnt2, cnt3);
+    trace("number of total exclusive accesses is %d\n", srwlock_protected_value);
+}
+
 START_TEST(sync)
 {
     HMODULE hdll = GetModuleHandleA("kernel32.dll");
@@ -1959,4 +2043,5 @@ START_TEST(sync)
     test_condvars_base();
     test_condvars_consumer_producer();
     test_srwlock_base();
+    test_srwlock_example();
 }
-- 
1.7.9.5