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More properly fix the threading lock. Instead of waiting on a packet, release it and wait on the packetqueue.

This commit is contained in:
Isaac Connor 2021-09-14 16:21:32 -04:00
parent 167dece604
commit bf5c0a8617
3 changed files with 28 additions and 14 deletions
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30
src/zm_monitor.cpp
View File

@ -1735,10 +1735,6 @@ bool Monitor::Analyse() {
return false;
}
// Store the it that points to our snap we will need it later
packetqueue_iterator snap_it = *analysis_it;
packetqueue.increment_it(analysis_it);
// signal is set by capture
bool signal = shared_data->signal;
bool signal_change = (signal != last_signal);
@ -1848,8 +1844,15 @@ bool Monitor::Analyse() {
while (!snap->decoded and !zm_terminate and !analysis_thread->Stopped()) {
// Need to wait for the decoder thread.
Debug(1, "Waiting for decode");
packetqueue.unlock(packet_lock);
packetqueue.notify_all(); // decode might be waiting
packet_lock->wait();
packetqueue.wait();
// Another thread may have moved our it. Unlikely but possible
packet_lock = packetqueue.get_packet(analysis_it);
if (!packet_lock) return false;
snap = packet_lock->packet_;
if (!snap->image and snap->decoded) {
Debug(1, "No image but was decoded, giving up");
delete packet_lock;
@ -1947,14 +1950,14 @@ bool Monitor::Analyse() {
// Must start on a keyframe so rewind. Only for passthrough though I guess.
// FIXME this iterator is not protected from invalidation
packetqueue_iterator *start_it = packetqueue.get_event_start_packet_it(
snap_it, 0 /* pre_event_count */
*analysis_it, 0 /* pre_event_count */
);
// This gets a lock on the starting packet
ZMLockedPacket *starting_packet_lock = nullptr;
std::shared_ptr<ZMPacket> starting_packet = nullptr;
if (*start_it != snap_it) {
if (*start_it != *analysis_it) {
starting_packet_lock = packetqueue.get_packet(start_it);
if (!starting_packet_lock) {
Warning("Unable to get starting packet lock");
@ -1968,12 +1971,12 @@ bool Monitor::Analyse() {
event = new Event(this, starting_packet->timestamp, "Continuous", noteSetMap);
// Write out starting packets, do not modify packetqueue it will garbage collect itself
while (starting_packet and ((*start_it) != snap_it)) {
while (starting_packet and ((*start_it) != *analysis_it)) {
event->AddPacket(starting_packet);
// Have added the packet, don't want to unlock it until we have locked the next
packetqueue.increment_it(start_it);
if ((*start_it) == snap_it) {
if ((*start_it) == *analysis_it) {
if (starting_packet_lock) delete starting_packet_lock;
break;
}
@ -2051,12 +2054,12 @@ bool Monitor::Analyse() {
if (!event) {
packetqueue_iterator *start_it = packetqueue.get_event_start_packet_it(
snap_it,
*analysis_it,
(pre_event_count > alarm_frame_count ? pre_event_count : alarm_frame_count)
);
ZMLockedPacket *starting_packet_lock = nullptr;
std::shared_ptr<ZMPacket> starting_packet = nullptr;
if (*start_it != snap_it) {
if (*start_it != *analysis_it) {
starting_packet_lock = packetqueue.get_packet(start_it);
if (!starting_packet_lock) return false;
starting_packet = starting_packet_lock->packet_;
@ -2071,11 +2074,11 @@ bool Monitor::Analyse() {
shared_data->state = state = ALARM;
// Write out starting packets, do not modify packetqueue it will garbage collect itself
while (*start_it != snap_it) {
while (*start_it != *analysis_it) {
event->AddPacket(starting_packet);
packetqueue.increment_it(start_it);
if ( (*start_it) == snap_it ) {
if ( (*start_it) == (*analysis_it) ) {
if (starting_packet_lock) delete starting_packet_lock;
break;
}
@ -2262,6 +2265,7 @@ bool Monitor::Analyse() {
if (function == MODECT or function == MOCORD)
UpdateAnalysisFPS();
}
packetqueue.increment_it(analysis_it);
packetqueue.unlock(packet_lock);
shared_data->last_read_time = std::chrono::system_clock::to_time_t(std::chrono::system_clock::now());

9
src/zm_packetqueue.cpp
View File

@ -663,3 +663,12 @@ void PacketQueue::setPreEventVideoPackets(int p) {
pre_event_video_packet_count = 1;
// We can simplify a lot of logic in queuePacket if we can assume at least 1 packet in queue
}
void PacketQueue::notify_all() {
condition.notify_all();
};
void PacketQueue::wait() {
std::unique_lock<std::mutex> lck(mutex);
condition.wait(lck);
}

3
src/zm_packetqueue.h
View File

@ -81,7 +81,8 @@ class PacketQueue {
);
bool is_there_an_iterator_pointing_to_packet(const std::shared_ptr<ZMPacket> &zm_packet);
void unlock(ZMLockedPacket *lp);
void notify_all() { condition.notify_all(); };
void notify_all();
void wait();
};
#endif /* ZM_PACKETQUEUE_H */