I get the following annotation of my code. I understand that the line 1076 was executed 209 times and the line 1078 was executed 2 times. From here I can conclude that the line 1082 should be executed 209 - 2 = 207 times. But it is not the case. Why?
209: 1076: if (some condition) {
-: 1077: // some condition happen
2: 1078: LOG("some condition happen”);
-: 1079: return STATUS_DONE;
-: 1080: }
-: 1081:
408: 1082: if (another condition) {
Thanks in advance, Stella
Related
I am working on a KMM project and am currently developing a model layer. In order to work with data I was planning to create a singleton like so:
#ThreadLocal object Repository {
private var dao: DataAccessObject? = null
private val scope = CoroutineScope(Dispatchers.Main)
fun injectDao(dao: DataAccessObject) {
scope.async {
Repository.dao = dao
}
}
suspend fun create(dataObjectType: TypeOfDataObject): DataObject? {
var dataObject: DataObject? = null
val job = scope.async {
dataObject = dao?.create(dataObjectType = dataObjectType)
}
job.await()
return dataObject
}
}
In such implementation as you see the request to the database is handled in Main thread, which's quite not good. But it works and the data is returned from the function correctly. The next obvious step is to try to run it in background scope. To make it we should just redeclare scope:
private val scope = CoroutineScope(Dispatchers.Default)
When we run the code and call create function from somewhere it falls with
Uncaught Kotlin exception: kotlin.native.concurrent.InvalidMutabilityException: mutation attempt of frozen kotlin.native.internal.Ref#5761ad88
2021-02-02 23:54:50.408645+0300 Plendy[28960:2893398] [] nw_protocol_get_quic_image_block_invoke dlopen libquic failed
at 0 Shared 0x000000010d51640f kfun:kotlin.Throwable#<init>(kotlin.String?){} + 95 (/Users/teamcity/buildAgent/work/f01984a9f5203417/runtime/src/main/kotlin/kotlin/Throwable.kt:23:37)
at 1 Shared 0x000000010d50f0bd kfun:kotlin.Exception#<init>(kotlin.String?){} + 93 (/Users/teamcity/buildAgent/work/f01984a9f5203417/runtime/src/main/kotlin/kotlin/Exceptions.kt:23:44)
at 2 Shared 0x000000010d50f32d kfun:kotlin.RuntimeException#<init>(kotlin.String?){} + 93 (/Users/teamcity/buildAgent/work/f01984a9f5203417/runtime/src/main/kotlin/kotlin/Exceptions.kt:34:44)
at 3 Shared 0x000000010d5448cd kfun:kotlin.native.concurrent.InvalidMutabilityException#<init>(kotlin.String){} + 93 (/Users/teamcity/buildAgent/work/f01984a9f5203417/runtime/src/main/kotlin/kotlin/native/concurrent/Freezing.kt:22:60)
at 4 Shared 0x000000010d5460af ThrowInvalidMutabilityException + 431 (/Users/teamcity/buildAgent/work/f01984a9f5203417/runtime/src/main/kotlin/kotlin/native/concurrent/Internal.kt:92:11)
at 5 Shared 0x000000010d6470b0 MutationCheck + 128
at 6 Shared 0x000000010d5640f8 kfun:kotlin.native.internal.Ref#<set-element>(1:0){} + 104 (/Users/teamcity/buildAgent/work/f01984a9f5203417/runtime/src/main/kotlin/kotlin/native/internal/Ref.kt:12:5)
at 7 Shared 0x000000010d4a1d5b kfun:com.plendy.PlendyCore.Model.KNPlendyData.$create$lambda-1COROUTINE$4.invokeSuspend#internal + 779 (/Users/petr/Documents/Projects/Plendy/Android/Plendy/PlendyCore/src/commonMain/kotlin/com/plendy/PlendyCore/Model/KNPlendyData.kt:23:13)
at 8 Shared 0x000000010d537958 kfun:kotlin.coroutines.native.internal.BaseContinuationImpl#resumeWith(kotlin.Result<kotlin.Any?>){} + 760 (/Users/teamcity/buildAgent/work/f01984a9f5203417/runtime/src/main/kotlin/kotlin/coroutines/ContinuationImpl.kt:30:39)
at 9 Shared 0x000000010d6d7a78 kfun:kotlinx.coroutines.DispatchedTask#run(){} + 2680 (/opt/buildAgent/work/44ec6e850d5c63f0/kotlinx-coroutines-core/common/src/internal/DispatchedTask.kt:106:71)
at 10 Shared 0x000000010d687fb8 kfun:kotlinx.coroutines.EventLoopImplBase#processNextEvent(){}kotlin.Long + 840 (/opt/buildAgent/work/44ec6e850d5c63f0/kotlinx-coroutines-core/common/src/EventLoop.common.kt:274:18)
at 11 Shared 0x000000010d6efbbb kfun:kotlinx.coroutines#runEventLoop(kotlinx.coroutines.EventLoop?;kotlin.Function0<kotlin.Boolean>){} + 843 (/opt/buildAgent/work/44ec6e850d5c63f0/kotlinx-coroutines-core/native/src/Builders.kt:80:40)
at 12 Shared 0x000000010d6f8d39 kfun:kotlinx.coroutines.WorkerCoroutineDispatcherImpl.start$lambda-0#internal + 409 (/opt/buildAgent/work/44ec6e850d5c63f0/kotlinx-coroutines-core/native/src/Workers.kt:49:17)
at 13 Shared 0x000000010d6f8f30 kfun:kotlinx.coroutines.WorkerCoroutineDispatcherImpl.$start$lambda-0$FUNCTION_REFERENCE$35.invoke#internal + 64 (/opt/buildAgent/work/44ec6e850d5c63f0/kotlinx-coroutines-core/native/src/Workers.kt:47:24)
at 14 Shared 0x000000010d6f8f90 kfun:kotlinx.coroutines.WorkerCoroutineDispatcherImpl.$start$lambda-0$FUNCTION_REFERENCE$35.$<bridge-UNN>invoke(){}#internal + 64 (/opt/buildAgent/work/44ec6e850d5c63f0/kotlinx-coroutines-core/native/src/Workers.kt:47:24)
at 15 Shared 0x000000010d545d59 WorkerLaunchpad + 185 (/Users/teamcity/buildAgent/work/f01984a9f5203417/runtime/src/main/kotlin/kotlin/native/concurrent/Internal.kt:69:54)
at 16 Shared 0x000000010d64ba4f _ZN6Worker19processQueueElementEb + 3135
at 17 Shared 0x000000010d64adf6 _ZN12_GLOBAL__N_113workerRoutineEPv + 54
at 18 libsystem_pthread.dylib 0x0000000110a86950 _pthread_start + 224
at 19 libsystem_pthread.dylib 0x0000000110a8247b thread_start + 15
What is strange that the data is written to the db, meaning that dao is called successfully, but data isn't returning from the function, because the exception occurs earlier. At this point I don't understand to what frozen object does the exception relates? What I've tried next is to remove job.await() line and it worked perfectly with no exceptions besides of cause having null in function's output.
So my question is: how to make code run in a background thread still having an ability to wait for its output?
You should include more of the exception info to help figure out what's happening, and you can use ensureNeverFrozen to help identify when something is being inadvertently frozen. However, in this case, I think I can figure it out.
In this case, capturing a reference to dataObject in your background lambda will freeze it. Trying to reassign it is (probably) throwing your exception.
var dataObject: DataObject? = null
val job = scope.async {
//Trying to assign the frozen dataObject will fail
dataObject = dao?.create(dataObjectType = dataObjectType)
}
Since you're already in a suspend function, why not just use something like withContext?
suspend fun create(dataObjectType: TypeOfDataObject): DataObject? {
val dataObject = withContext(Dispatchers.Default) {
dao?.create(dataObjectType = dataObjectType)
}
return dataObject
}
And if you're going that far ...
suspend fun create(dataObjectType: TypeOfDataObject): DataObject? = withContext(Dispatchers.Default) {
dao?.create(dataObjectType = dataObjectType)
}
I've run into an interesting issue with the Swift compiler, which seems to be caused by a very simple generic function. I've got a workaround, but I'd really like to understand what the underlying issue is.
In my app I have a requirement to fade in some UICollectionViewCells in a given order, sequentially, with a slight overlap between the animations.
I've implemented this using the methods below. The revealCells method takes an array of cells. If the collection is empty, it simply returns. Otherwise it animates the fade-in on the first cell in the array, and then waits a certain amount of time before making a recursive call to itself, passing all the cells except the one it just animated.
Code below:
func revealCells(cells:[UICollectionViewCell],animationTime:NSTimeInterval,overlap:Double) {
if cells.count > 0 {
let firstCell = cells.first
UIView.animateWithDuration(0.3, animations: { () -> Void in
firstCell?.alpha = 1.0
let timeMinusOverlap = animationTime - overlap
let delayTime = dispatch_time(DISPATCH_TIME_NOW,Int64(timeMinusOverlap * Double(NSEC_PER_SEC)))
dispatch_after(delayTime, dispatch_get_main_queue(), { () -> Void in
self.revealCells(self.cdr(cells),animationTime: animationTime,overlap: overlap)
})
})
}
}
}
//Returns the collection passed into the function with its first element removed
//i.e the traditional LISP cdr function
func cdr<T>(input:[T]) -> [T] {
var rVal = [T]()
if input.count == 1 {
rVal.append(input.first!)
} else {
rVal = [T](input[1...input.count-1])
}
return rVal
}
All this works fine in the simulator. But when I try to archive the build, the swift compiler crashes with the message Swift Compiler Error Command failed due to signal: Segmentation fault 11. My setup is Xcode 6.3.1 (iOSSDK 8.3), and my min deployment target is 8.3.
Fixing the problem is trivial - if I just replace the code inside the dispatch_after with:
let newCells = [UICollectionViewCell](cells[1...cells.count-1])
self.revealCells(newCells,animationTime: animationTime,overlap: overlap)
the problem goes away. So it seems to be something to do with the generic function, or possibly something block related.
Stack trace is:
0 swift 0x000000010105ba18 llvm::sys::PrintStackTrace(__sFILE*) + 40
1 swift 0x000000010105bef4 SignalHandler(int) + 452
2 libsystem_platform.dylib 0x00007fff8725ef1a _sigtramp + 26
3 libsystem_platform.dylib 0x000000000000000f _sigtramp + 2027557135
4 swift 0x00000001021a98cb llvm::AsmPrinter::EmitFunctionBody() + 4379
5 swift 0x000000010116c84c llvm::ARMAsmPrinter::runOnMachineFunction(llvm::MachineFunction&) + 220
6 swift 0x0000000100d81d13 llvm::MachineFunctionPass::runOnFunction(llvm::Function&) + 99
7 swift 0x00000001024d5edf llvm::FPPassManager::runOnFunction(llvm::Function&) + 495
8 swift 0x00000001024d60cb llvm::FPPassManager::runOnModule(llvm::Module&) + 43
9 swift 0x00000001024d658f llvm::legacy::PassManagerImpl::run(llvm::Module&) + 975
10 swift 0x0000000100a09b41 performIRGeneration(swift::IRGenOptions&, swift::Module*, swift::SILModule*, llvm::StringRef, llvm::LLVMContext&, swift::SourceFile*, unsigned int) + 4369
11 swift 0x0000000100a09cb3 swift::performIRGeneration(swift::IRGenOptions&, swift::SourceFile&, swift::SILModule*, llvm::StringRef, llvm::LLVMContext&, unsigned int) + 51
12 swift 0x0000000100945687 frontend_main(llvm::ArrayRef<char const*>, char const*, void*) + 6647
13 swift 0x0000000100943ae6 main + 1814
14 libdyld.dylib 0x00007fff8a46b5c9 start + 1
(a long list of program arguments, which are mostly the names of file being compiled)
1. Running pass 'Function Pass Manager' on module '/Users/tolleyr/Library/Developer/Xcode/DerivedData/ParseTestQuiz-fgnfjkxxlyqfnrfrfntgtsjnrcfv/Build/Intermediates/ArchiveIntermediates/ParseTestQuiz/IntermediateBuildFilesPath/ParseTestQuiz.build/Release-iphoneos/ParseTestQuiz.build/Objects-normal/armv7/QuizQuestionViewController.o'.
2. Running pass 'ARM Assembly / Object Emitter' on function '#_TFC13ParseTestQuiz26QuizQuestionViewController13viewDidAppearfS0_FSbT_'
(the last part enabled me to figure out what code was causing the problem). The command being run was CompileSwift normal armv7
I'm going to file a radar for this, since the compiler itself is crashing , but thought I'd post it here in case anyone has an idea of what might be going on, or has run into the same issue.
I want to add some sections to UICollectionView. insertSections at the index zero didn't work for me. So my idea was to insertSections at the end and then use moveSection:toSection: to move the elements from the end to the beginning. Here I get
NSInternalInconsistencyException Reason: attempt to move section 36, but there are only 36 sections before the update
I can only provide C# code, but you can also post Objective-C/Swift.
this.controller.CollectionView.PerformBatchUpdatesAsync (
delegate() {
nint sectionsBefore = this.controller.CurrentNumberOfSections;
this.controller.CurrentNumberOfSections += 12;
this.controller.CollectionView.InsertSections(NSIndexSet.FromNSRange(new NSRange(sectionsBefore,12)));
for(nint i=sectionsBefore; i<=this.controller.CurrentNumberOfSections; i++){
this.controller.CollectionView.MoveSection(i,0);
}
}
);
Edit:
Here is an output of the variables:
sectionsBefore: 36
CurrentNumberOfSections: 48
Range: <NSIndexSet: 0x7a77b9b0>[number of indexes: 12 (in 1 ranges), indexes: (36-47)]
36
37
38
39
40
41
42
43
44
45
46
47
If you have 36 sections then then your valid section indexes are 0-35, but your loop will end up calling MoveSection(36, 0). You should use < instead of <=.
I have a problem using Dart postgresql database driver (xxgreg on Github) insofar as when the postgresql server is not running and it needs to be, I am unable to correctly handle the error. I’ve attempted to solve this for a while now, so any help would be appreciated. I can easily work around it by handling it silently and simply testing if the database connection object is null, however I think it should be possible to handle the raising of an error. It should be noted that when the Postgresql server is running, there is no problem.
The error that I am getting is as follows :
“Uncaught Error: Exception: fConnectToDb: Database is not connected
Stack Trace: ………….”
The problem area relates to these lines of code : (Line 663 is called from line 169 below)
663 async.Future<bool> fConnectToDb(String sUri) {
664 async.Completer<bool> oCompleter = new async.Completer<bool>();
665
666 pg.connect(sUri)
667 .catchError((oError) {
668 String sErrorMsg = (oError is SocketException) ?
669 "Database is not connected"
670 : "Fatal error encountered ${oError}";
671 throw("fConnectToDb: ${sErrorMsg}");
//(expanded below)
I have previously encountered problems in this area where at line 671, instead of throwing an exception, I called an internal method which displayed an error, and terminated the program. I found however what appeared to be a problem doing that, and I found in that situation, throwing an error enabled the program to exit the Future method, and not doing that appeared to be the problem. The problem may relate to the Future not being completed, but I don’t know how to do that and also throw an exception.
The overall code in-question is as follows. I put a try at line 167… 406, however that doesn’t catch the error either.
164 /*
165 * Connect to database
166 */
167 try {
168 sCheckpoint = "Connect to Database";
169 fConnectToDb(sUri)
170 .catchError((oError) =>
171 fFatal(sCheckpoint, "Error = \n${oError}"))
172 .then((_) {
173 if (ogDb == null) // ogDb is global object for db connection
174 fFatal(sCheckpoint, "Database did not connect");
175
176 /*
177 * Perform an SQL Select to test connection
178 */
179 ogPrintLine.fPrintForce("Testing Db connection .....");
180 sCheckpoint = "test connection";
181 return fProcessSqlSelect ("SELECT count(*) FROM ${S_TABLE_NAME}",
182 false);
183 }).then((llResult) {
184
…………
…………
// (catch related to line 167)
406 } catch(oError) {fFatal("Program Main()",
407 "Checkpoint ${sCheckpoint}, Error = \n${oError}");}
408 }
………..
………..
660 /*
661 * Connect To Database
662 */
663 async.Future<bool> fConnectToDb(String sUri) {
664 async.Completer<bool> oCompleter = new async.Completer<bool>();
665
666 pg.connect(sUri)
667 .catchError((oError) {
668 String sErrorMsg = (oError is SocketException) ?
669 "Database is not connected"
670 : "Fatal error encountered ${oError}";
671 throw("fConnectToDb: ${sErrorMsg}");
672
673 }).then((pg.Connection oDb) {
674 ogDb = oDb;
675 oCompleter.complete(true);
676 return;
677
678 });
679
680 return oCompleter.future;
681 }
As far as I can determine, it appears to me that it's Ok to throw an error in a Future providing it's followed by a catchError() that doesn't throw an error.
The following code appears to solve the problem that I was having :
/*
* Connect To Database
*/
async.Future<bool> fConnectToDb(String sUri) {
async.Completer<bool> oCompleter = new async.Completer<bool>();
pg.connect(sUri).then((pg.Connection oDb) {
ogDb = oDb; // assign to global database object
oCompleter.complete(true);
return;
}).catchError((oError) =>
fFatal("fConnectToDb", "Error=\n${oError}"));
return oCompleter.future;
}
Could someone please explain to me why in the following code (using r25630 Windows), the value of iInsertTot at line 241 is null, or more to the point, why is line 234 ("return iInsertTot;") not executed and therefore at line 241, iInsertTot is null. The value of iInsertTot at lines 231/232 is an integer. While I can and probably should code this differently, I thought that I would try and see if it worked, because my understanding of Futures and Chaining was that it would work. I have used “return” in a similar way before and it worked, but I was returning null in those cases (eg. line 201 below).
/// The problem lines are :
233 fUpdateTotalsTable().then((_) {
234 return iInsertTot;
235 });
While running in the debugger, it appears that line 234 “return iInsertTot;” is never actually executed. Running from command line has the same result.
The method being called on line 233 (fUpdateTotalsTable) is something I am just in the process of adding, and it consists basically of sync code at this stage. However, the debugger appears to go through it correctly.
I have included the method “fUpdateTotalsTable()” (line 1076) just in case that is causing a problem.
Lines 236 to 245 have just been added, however just in case that code is invalid I have commented those lines out and run with the same problem occurring.
218 /*
219 * Process Inserts
220 */
221 }).then((_) {
222 sCheckpoint = "fProcessMainInserts";
223 ogPrintLine.fPrintForce ("Processing database ......");
224 int iMaxInserts = int.parse(lsInput[I_MAX_INSERTS]);
225 print ("");
226 return fProcessMainInserts(iMaxInserts, oStopwatch);
227 /*
228 * Update the 'totals' table with the value of Inserts
229 */
230 }).then((int iReturnVal) {
231 int iInsertTot = iReturnVal;
232 sCheckpoint = "fUpdateTotalsTable (insert value)";
233 fUpdateTotalsTable().then((_) {
234 return iInsertTot;
235 });
236 /*
237 * Display totals for inserts
238 */
239 }).then((int iInsertTot) {
240 ogTotals.fPrintTotals(
241 "${iInsertTot} rows inserted - Inserts completed",
242 iInsertTot, oStopwatch.elapsedMilliseconds);
243
244 return null;
245 /*
192 /*
193 * Clear main table if selected
194 */
195 }).then((tReturnVal) {
196 if (tReturnVal)
197 ogPrintLine.fPrintForce("Random Keys Cleared");
198 sCheckpoint = "Clear Table ${S_TABLE_NAME}";
199 bool tClearTable = (lsInput[I_CLEAR_YN] == "y");
200 if (!tFirstInstance)
201 return null;
202 return fClearTable(tClearTable, S_TABLE_NAME);
203
204 /*
205 * Update control row to increment count of instances started
206 */
207 }).then((_) {
1073 /*
1074 * Update totals table with values from inserts and updates
1075 */
1076 async.Future<bool> fUpdateTotalsTable() {
1077 async.Completer<bool> oCompleter = new async.Completer<bool>();
1078
1079 String sCcyValue = ogCcy.fCcyIntToString(ogTotals.iTotAmt);
1080
1081 print ("\n********* Total = ${sCcyValue} \n");
1082
1083 oCompleter.complete(true);
1084 return oCompleter.future;
1085 }
Your function L230-235 does not return anything and that's why your iInsertTot is null L239. To make it work you have to add a return at line 233.
231 int iInsertTot = iReturnVal;
232 sCheckpoint = "fUpdateTotalsTable (insert value)";
233 return fUpdateTotalsTable().then((_) {
234 return iInsertTot;
235 });