Unity3d Parse FindAsync method freezes UI - unity3d

I'm running a simple Parse FindAsync method as show below (on Unity3d):
Task queryTask = query.FindAsync();
Debug.Log("Start");
Thread.Sleep(5000);
Debug.Log("Middle");
while (!queryTask.IsCompleted) {
Debug.Log("Waiting");
Thread.Sleep(1);
}
Debug.Log("Finished");
I'm running this method on a separate thread and I put a load circle on UI. My load freezes (+- 1 second) somewhere in the middle of the Thread.sleep method. It's look like when findAsync finishes the process it freezes the UI until it complete their job. Is there anything I could do?
Ps: This works perfectly on editor, the problem is on Android devices.
Ps2: I'm running parse 1.4.1
Ps3: I already tried the continueWith method, but the same problem happens.

IEnumerator RunSomeLongLastingTask () {
Task queryTask = query.FindAsync();
Debug.Log("Start");
//Thread.Sleep(5000); //Replace with below call
yield WaitForSeconds(5); //Try this
Debug.Log("Middle");
while (!queryTask.IsCompleted) {
Debug.Log("Waiting");
//Thread.Sleep(1);
yield WaitForSeconds(0.001f);
}
Debug.Log("Finished");
}
To call this function, use:
StartCoroutine(RunSomeLongLastingTask());

Making the thread sleep might not be a good idea, mainly because the number of threads available is different on each device.
Unity as a built-in scheduler that uses coroutines, so it is better to use it.
IEnumerator RunSomeLongLastingTask()
{
Task queryTask = query.FindAsync();
while (!queryTask.IsCompleted)
{
Debug.Log("Waiting"); // consider removing this log because it also impact performance
yield return null; // wait until next frame
}
}
Now, one possible issue is if your task take too much CPU, then the UI will still not be responsive. If possible, try to give a lower priority to this task.

Related

Background Process as NSOperation or Thread to monitor and update File

I want to check if a pdf file is changed or not, and if is changed i want to update the corresponding view. I don't know if it's more suitable to use a background process as a Thread or as an NSOperation to do this task. The Apple Documentation says: "Examples of tasks that lend themselves well to NSOperation include network requests, image resizing, text processing, or any other repeatable, structured, long-running task that produces associated state or data.But simply wrapping computation into an object doesn’t do much without a little oversight".
Also, if I understood correctly from the documentation, a Thread once started can't be stopped during his execution while an NSOperation could be paused or stopped and also they could rely on dependency to wait the completion of another task.
The workflow of this task should be more or less this diagram:
Task workflow
I managed to get the handler working after the notification of type .write has been sent. If i monitor for example a *.txt file everything works as expected and i receive only one notification. But i am monitoring a pdf file which is generated from terminal by pdflatex and thus i receive with '.write' nearly 15 notification. If i change to '.attrib' i get 3 notification. I need the handler to be called only once, not 15 or 3 times. Do you have any idea how can i do it or is not possible with a Dispatch Source? Maybe there is a way to execute a dispatchWorkItem only once?
I have tried to implement it like this(This is inside a FileMonitor class):
func startMonitoring()
{
....
let fileSystemRepresentation = fileManager.fileSystemRepresentation(withPath: fileStringURL)
let fileDescriptor = open(fileSystemRepresentation, O_EVTONLY)
let newfileMonitorSource = DispatchSource.makeFileSystemObjectSource(fileDescriptor: fileDescriptor,
eventMask: .attrib,
queue: queue)
newfileMonitorSource.setEventHandler(handler:
{
self.queue.async
{
print(" \n received first write event, removing handler..." )
self.newfileMonitorSource.setEventHandler(handler: nil)
self.test()
}
})
self.fileMonitorSource = newfileMonitorSource
fileMonitorSource!.resume()
}
func test()
{
fileMonitorSource?.cancel()
print(" restart monitoring ")
startMonitoring()
}
I have tried to reassign the handler in test(), but it's not working(if a regenerate the pdf file, what is inside the new handler it's not executed) and to me, doing in this way, it seems a bit boilerplate code. I have also tried the following things:
suspend the DispatchSource in the setEventHandler of startMonitoring() (passing nil), but then when i am resuming it, i get the remaining .write events.
cancel the DispatchSource object and recall the startMonitoring() as you can see in the code above, but in this way i create and destroy the DispatchSource object everytime i receive an event, which i don't like because the cancel() function shoul be called in my case only when the user decide to disable this feauture i am implementing.
I will try to write better how the workflow of the app should be so you can have an more clear idea of what i am doing:
When the app starts, a functions sets the default value of some checkboxes of the window preference. The user can modify this checkboxes. So when the user open a pdf file, the idea is to launch in a background thread the following task:
I create a new queue call it A and launch asynch an infinite while where i check the value of the UserDefault checkboxe (that i use to reload and update the pdf file) and two things could happen
if the user set the value to off and the pdf document has been loaded there could be two situations:
if there is no current monitoring of the file (when the app starts): continue to check the checkboxe value
if there is currently a monitoring of the file: stop it
if the user set value to on and the pdf document has been loaded in this background thread (the same queue A) i will create a class Monitor (that could be a subclass of NSThread or a class that uses DispatchSourceFileSystemObject like above), then i will call startMonitoring() that will check the date or .write events and when there is a change it will call the handler. Basically this handler should recall the main thread (the main queue) and check if the file can be loaded or is corrupted and if so update the view.
Note: The infinite while loop(that should be running in the background), that check the UserDefault related to the feature i am implementing it's launched when the user open the pdf file.
Because of the problem above (multiple handlers calls), i should use the cancel() function when the user set checkboxe to off, and not create/destroy the DispatchSource object everytime i receive a .write event.

Gstreamer 1.0 Pause signal

I need to detect when the current playing audio/video is paused. I cannot find anything for 1.0. My app is a bit complex but here is condensed code
/* This function is called when the pipeline changes states. We use it to
* keep track of the current state. */
static void state_changed_cb(GstBus *bus, GstMessage *msg, CustomData *data)
{
GstState old_state, new_state, pending_state;
gst_message_parse_state_changed(msg, &old_state, &new_state, &pending_state);
if(GST_MESSAGE_SRC(msg) == GST_OBJECT(data->playbin))
{
g_print("State set to %s\n", gst_element_state_get_name(new_state));
}
}
gst_init(&wxTheApp->argc, &argv);
m_playbin = gst_element_factory_make("playbin", "playbin");
if(!m_playbin)
{
g_printerr("Not all elements could be created.\n");
exit(1);
}
CustomData* data = new CustomData(xid, m_playbin);
GstBus *bus = gst_element_get_bus(m_playbin);
gst_bus_set_sync_handler(bus, (GstBusSyncHandler) create_window, data, NULL);//here I do video overly stuffs
g_signal_connect (G_OBJECT (bus), "message::state-changed", (GCallback)state_changed_cb, &data);
What do I do wrong? I cannot find working example on connecting such events on Gstreamer 1.0 and 0.x seems a bit different than 1.0 so the vast exaples there don't help
UPDATE
I have found a way to get signals. I run wxWidgets timer with 500ms time span and each time timer fires I call
GstMessage* msg = gst_bus_pop(m_bus);
if(msg!=NULL)
{
g_print ("New Message -- %s\n", gst_message_type_get_name(msg->type));
}
Now I get a lot of 'state-change' messages. Still I want to know if that message is for Pause or Stop or Play or End of Media (I mean way to differentiate which message is this) so that I can notify the UI.
So while I get signals now, the basic problem, to get specific signals, remains unsolved.
You have to call gst_bus_add_signal_watch() (like in 0.10) to enable emission of the signals. Without that you can only use the other ways to get notified about GstMessages on that bus.
Also just to be sure, you need a running GLib main loop on the default main context for this to work. Otherwise you need to do things a bit different.
For the updated question:
Check the documentation: gst_message_parse_state_changed() can be used to parse the old, new and pending state from the message. This is also still the same as in 0.10. From the application point of view, and conceptionally nothing much has changed really between 0.10 and 1.0
Also you shouldn't do this timeout-waiting as it will block your wxwidget main loop. Easiest solution would be to use a sync bus handler (which you already have) and dispatch all messages from there to some callback on the wxwidget main loop.

Yield return in AssetBundle.CreateFromMemory

As documentation says IEnumerator methods are executed like thread, but I'm confused why
AssetBundleCreateRequest assetBundleCreateRequest = AssetBundle.CreateFromMemory(ByteArray);
yield return assetBundleCreateRequest;
freezes my game for 2 seconds. Can anybody explain?
Well it freezes for 2 seconds because that is what you are actually requesting with your yield return assetBundleCreateRequest
Asynchronous operation coroutine.
You can yield until asynchronous operation continues, or manually check whether it's done (isDone) or progress (progress). AsyncOperation
So right now you are requesting your coroutine to wait till your assetbundlecreaterequest is done.
For manually checking wheter the function is done, without having to freeze your application would be using the isdone or progress command instead
If you need further clarification feel free to comment.
Edit
Sample of using isdone
AssetBundleCreateRequest acr = AssetBundle.CreateFromMemory(decryptedData);
while (!acr.isDone)
{
yield;
}
AssetBundle bundle = acr.assetBundle;

QApplication::processEvents never returns

In my application I need to wait until external program (using QProcess) is finished. I want to keep the application responsible so blocking methods are unacceptable.
Also I need to disallow user input. I've tried to make QEventLoop and exec it with QEventLoop::ExcludeUserInputEvents flag, but as documentation says it only delays an event handling:
the events are not discarded; they will be delivered the next time processEvents() is called without the ExcludeUserInputEvents flag.
So I implemented simple event filter and install it on qApp (the idea is took from Qt Application: Simulating modal behaviour (enable/disable user input)). It works well, but sometimes QApplication::processEvents function never returns even if I specify the maximum timeout. Could anyone help me to understand for what reasons it periodically happens?
class UserInputEater : public QObject
{
public:
bool eventFilter(QObject *object, QEvent *event)
{
switch(event->type())
{
case QEvent::UpdateRequest:
case QEvent::UpdateLater:
case QEvent::Paint:
return QObject::eventFilter(object, event);
default:
return true;
}
}
};
-
UserInputEater eventEater;
qApp->installEventFilter(&eventEater);
QProcess prc;
prc.start("...");
while(!prc.waitForFinished(10))
{
if(qApp->hasPendingEvents())
{
// Sometimes it never returns from processEvents
qApp->processEvents(QEventLoop::AllEvents, 100);
}
}
qApp->removeEventFilter(&eventEater);
UPD: Seems like it depends of the timeout value for QProcess::waitForFinished.
I guess you are filtering some useful events (for example, QEvent::SockAct could be involved). Try to add some debug output and find out which event types you're actually filtering. Or it might be better to specify the black list of events you want to block instead of white list of events you want to allow. See this answer.
Also you shouldn't use return QObject::eventFilter(object, event);. You should use return false. All other event filters will be called automatically.
This solution however seems weird and unreasonable to me because you can just call setEnabled(false) for your top level widget to block user input, and then you can use QApplication::processEvents without any flags.

Confusion about CFNetwork, CFReadStreamOpen, and CFRunLoopRun

That sinking feeling when you realize you have no idea what's going on...
I've been using this code in my network code for almost two years without problems.
if (!CFReadStreamOpen(myReadStream)) {
CFStreamError myErr = CFReadStreamGetError(myReadStream);
if (myErr.error != 0) {
// An error has occurred.
if (myErr.domain == kCFStreamErrorDomainPOSIX) {
// Interpret myErr.error as a UNIX errno.
strerror(myErr.error);
} else if (myErr.domain == kCFStreamErrorDomainMacOSStatus) {
OSStatus macError = (OSStatus)myErr.error;
}
// Check other domains.
}
}
I believe it was originally based on the code samples given here:
http://developer.apple.com/library/mac/#documentation/Networking/Conceptual/CFNetwork/CFStreamTasks/CFStreamTasks.html
I recently noticed, however, that some connections are failing, because CFReadStreamOpen returns false but the error code is 0. After staring at the above link some more, I noticed the CFRunLoopRun() statement, and added it:
if (!CFReadStreamOpen(myReadStream)) {
CFStreamError myErr = CFReadStreamGetError(myReadStream);
if (myErr.error != 0) {
// An error has occurred.
if (myErr.domain == kCFStreamErrorDomainPOSIX) {
// Interpret myErr.error as a UNIX errno.
strerror(myErr.error);
} else if (myErr.domain == kCFStreamErrorDomainMacOSStatus) {
OSStatus macError = (OSStatus)myErr.error;
}
// Check other domains.
} else
// start the run loop
CFRunLoopRun();
}
This fixed the connection problem. However, my app started showing random problems - interface sometimes not responsive, or not drawing, text fields not editable, that kind of stuff.
I've read up on CFReadStreamOpen and on run loops (specifically, that the main run loop runs by itself and I shouldn't run a run loop unless I'm setting it up myself in a secondary thread - which I'm not, as far as I know). But I'm still confused about what's actually happening above. Specifically:
1) Why does CFReadStreamOpen sometimes return FALSE and error code 0? What does that actually mean?
2) What does the CFRunLoopRun call actually do in the above code? Why does the sample code make that call - if this code is running in the main thread I shouldn't have to run the run loop?
I guess I'll answer my own question, as much as I can.
1) In my code, at least, CFReadStreamOpen always seems to return false. The documentation is a bit confusing, but I read it to mean the stream wasn't opened yet, but will be open later in the run loop.
2) Most of the calls I was making were happening in the main thread, where the run loop was already running, so calling CFRunLoopRun was unnecessary. The call that was giving me problems was happening inside a block, which apparently spawned a new thread. This new thread didn't start a new run loop - so the stream would never open unless I explicitly ran the new thread's run loop.
I'm still not 100% clear on what happens if I call CFRunLoopRun() on a thread with an already running run loop, but it's obviously not good.
I ended up ditching my home-brewed networking code and switching to ASIHTTPRequest, which I was considering to do anyway.