206 lines
4.3 KiB
C
206 lines
4.3 KiB
C
/*++
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Copyright (c) 1999, Microsoft Corporation
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Module Name:
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sample\utils.c
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Abstract:
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The file contains miscellaneous utilities.
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--*/
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#include "pchsample.h"
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#pragma hdrstop
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DWORD
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QueueSampleWorker(
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IN WORKERFUNCTION pfnFunction,
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IN PVOID pvContext
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)
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/*++
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Routine Description
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This function is called to queue a worker function in a safe fashion;
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if cleanup is in progress or if SAMPLE has stopped, this function
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discards the work-item.
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Locks
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Acquires exclusively g_ce.rwlLock
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Releases g_ce.rwlLock
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Arguments
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pfnFunction function to be called
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pvContext opaque ptr used in callback
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Return Value
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NO_ERROR if success
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Failure code o/w
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--*/
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{
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DWORD dwErr = NO_ERROR;
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BOOL bSuccess = FALSE;
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ACQUIRE_WRITE_LOCK(&(g_ce.rwlLock));
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do // breakout loop
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{
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// cannot queue a work function when SAMPLE has quit or is quitting
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if (g_ce.iscStatus != IPSAMPLE_STATUS_RUNNING)
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{
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dwErr = ERROR_CAN_NOT_COMPLETE;
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break;
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}
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bSuccess = QueueUserWorkItem((LPTHREAD_START_ROUTINE)pfnFunction,
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pvContext,
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0); // no flags
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if (bSuccess)
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g_ce.ulActivityCount++;
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else
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dwErr = GetLastError();
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} while (FALSE);
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RELEASE_WRITE_LOCK(&(g_ce.rwlLock));
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return dwErr;
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}
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BOOL
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EnterSampleAPI(
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)
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/*++
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Routine Description
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This function is called when entering a SAMPLE api, as well as when
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entering the input thread and timer thread. It checks to see if SAMPLE
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has stopped, and if so it quits; otherwise it increments the count of
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active threads.
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Locks
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Acquires exclusively g_ce.rwlLock
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Releases g_ce.rwlLock
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Arguments
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None
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Return Value
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TRUE if entered successfully
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FALSE o/w
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--*/
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{
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BOOL bEntered = FALSE;
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ACQUIRE_WRITE_LOCK(&(g_ce.rwlLock));
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if (g_ce.iscStatus is IPSAMPLE_STATUS_RUNNING)
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{
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// SAMPLE is running, so continue
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g_ce.ulActivityCount++;
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bEntered = TRUE;
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}
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RELEASE_WRITE_LOCK(&(g_ce.rwlLock));
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return bEntered;
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}
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BOOL
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EnterSampleWorker(
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)
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/*++
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Routine Description
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This function is called when entering a SAMPLE worker-function. Since
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there is a lapse between the time a worker-function is queued and the
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time the function is actually invoked by a worker thread, this function
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must check to see if SAMPLE has stopped or is stopping; if this is the
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case, then it decrements the activity count, releases the activity
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semaphore, and quits.
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Locks
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Acquires exclusively g_ce.rwlLock
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Releases g_ce.rwlLock
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Arguments
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None
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Return Value
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TRUE if entered successfully
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FALSE o/w
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--*/
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{
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BOOL bEntered = FALSE;
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ACQUIRE_WRITE_LOCK(&(g_ce.rwlLock));
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do // breakout loop
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{
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// SAMPLE is running, so the function may continue
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if (g_ce.iscStatus is IPSAMPLE_STATUS_RUNNING)
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{
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bEntered = TRUE;
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break;
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}
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// SAMPLE is not running, but it was, so the function must stop
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if (g_ce.iscStatus is IPSAMPLE_STATUS_STOPPING)
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{
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g_ce.ulActivityCount--;
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ReleaseSemaphore(g_ce.hActivitySemaphore, 1, NULL);
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break;
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}
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// SAMPLE probably never started. quit
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} while (FALSE);
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RELEASE_WRITE_LOCK(&(g_ce.rwlLock));
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return bEntered;
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}
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VOID
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LeaveSampleWorker(
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)
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/*++
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Routine Description
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This function is called when leaving a SAMPLE api or worker function.
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It decrements the activity count, and if it detects that SAMPLE has
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stopped or is stopping, it releases the activity semaphore.
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Locks
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Acquires exclusively g_ce.rwlLock
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Releases g_ce.rwlLock
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Arguments
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None
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Return Value
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TRUE if entered successfully
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FALSE o/w
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--*/
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{
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ACQUIRE_WRITE_LOCK(&(g_ce.rwlLock));
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g_ce.ulActivityCount--;
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if (g_ce.iscStatus is IPSAMPLE_STATUS_STOPPING)
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ReleaseSemaphore(g_ce.hActivitySemaphore, 1, NULL);
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RELEASE_WRITE_LOCK(&(g_ce.rwlLock));
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}
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