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Merge "Prevent PID tests from hanging."

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This commit is contained in:
Brad Miller (WPI)
2015-11-28 03:11:45 -08:00
committed by Gerrit Code Review
parent d998e53f9a e3191b0bfd
commit 84ca2ab0f5
2 changed files with 36 additions and 18 deletions
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51
wpilibc/Athena/src/Notifier.cpp
View File

@@ -13,8 +13,9 @@
Notifier *Notifier::timerQueueHead = nullptr;
priority_recursive_mutex Notifier::queueMutex;
priority_mutex Notifier::halMutex;
void *Notifier::m_notifier = nullptr;
int Notifier::refcount = 0;
std::atomic<int> Notifier::refcount{0};
/**
* Create a Notifier for timer event notification.
@@ -26,15 +27,15 @@ Notifier::Notifier(TimerEventHandler handler, void *param) {
wpi_setWPIErrorWithContext(NullParameter, "handler must not be nullptr");
m_handler = handler;
m_param = param;
{
std::lock_guard<priority_recursive_mutex> sync(queueMutex);
// do the first time intialization of static variables
if (refcount == 0) {
int32_t status = 0;
m_notifier = initializeNotifier(ProcessQueue, &status);
wpi_setErrorWithContext(status, getHALErrorMessage(status));
// do the first time intialization of static variables
if (refcount.fetch_add(1) == 0) {
int32_t status = 0;
{
std::lock_guard<priority_mutex> sync(halMutex);
if (!m_notifier)
m_notifier = initializeNotifier(ProcessQueue, &status);
}
refcount++;
wpi_setErrorWithContext(status, getHALErrorMessage(status));
}
}
@@ -47,13 +48,19 @@ Notifier::~Notifier() {
{
std::lock_guard<priority_recursive_mutex> sync(queueMutex);
DeleteFromQueue();
}
// Delete the static variables when the last one is going away
if (!(--refcount)) {
int32_t status = 0;
cleanNotifier(m_notifier, &status);
wpi_setErrorWithContext(status, getHALErrorMessage(status));
// Delete the static variables when the last one is going away
if (refcount.fetch_sub(1) == 1) {
int32_t status = 0;
{
std::lock_guard<priority_mutex> sync(halMutex);
if (m_notifier) {
cleanNotifier(m_notifier, &status);
m_notifier = nullptr;
}
}
wpi_setErrorWithContext(status, getHALErrorMessage(status));
}
// Acquire the mutex; this makes certain that the handler is
@@ -73,9 +80,19 @@ Notifier::~Notifier() {
void Notifier::UpdateAlarm() {
if (timerQueueHead != nullptr) {
int32_t status = 0;
updateNotifierAlarm(m_notifier,
(uint32_t)(timerQueueHead->m_expirationTime * 1e6),
&status);
// This locking is necessary in order to avoid two things:
// 1) Race condition issues with calling cleanNotifer() and
// updateNotifierAlarm() at the same time.
// 2) Avoid deadlock by making it so that this won't block waiting
// for the mutex to unlock.
// Checking refcount as well is unnecessary, but will not hurt.
if (halMutex.try_lock() && refcount != 0) {
if (m_notifier)
updateNotifierAlarm(m_notifier,
(uint32_t)(timerQueueHead->m_expirationTime * 1e6),
&status);
halMutex.unlock();
}
wpi_setStaticErrorWithContext(timerQueueHead, status,
getHALErrorMessage(status));
}

3
wpilibc/shared/include/Notifier.h
View File

@@ -28,8 +28,9 @@ class Notifier : public ErrorBase {
private:
static Notifier *timerQueueHead;
static priority_recursive_mutex queueMutex;
static priority_mutex halMutex;
static void *m_notifier;
static int refcount;
static std::atomic<int> refcount;
static void ProcessQueue(
uint32_t mask, void *params); // process the timer queue on a timer event