Flow data pin support for add ons #334

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LindyHopperGT wants to merge 20 commits into MothCocoon:5.x from LindyHopperGT:FlowDataPinSupportForAddOns

Source/Flow/Private/Asset/FlowDeferredTransitionScope.cpp

-Original file line number
+Diff line change
@@ -0,0 +1,32 @@
+    // Copyright https://github.com/MothCocoon/FlowGraph/graphs/contributors
+    #include "Asset/FlowDeferredTransitionScope.h"
+    #include "FlowAsset.h"
+    #include "Interfaces/FlowExecutionGate.h"
+    void FFlowDeferredTransitionScope::EnqueueDeferredTrigger(const FFlowDeferredTriggerInput& Entry)
+    {
+    	check(bIsOpen);
+    	DeferredTriggers.Add(Entry);
+    }
+    bool FFlowDeferredTransitionScope::TryFlushDeferredTriggers(UFlowAsset& OwningFlowAsset)
+    {
+    	// Ensure the scope is closed before beginning flushing
+    	CloseScope();
+    	// Remove and trigger each deferred trigger input
+    	while (!DeferredTriggers.IsEmpty() && !FFlowExecutionGate::IsHalted())
+    	{
+    		const FFlowDeferredTriggerInput Entry = DeferredTriggers[0];
+    		DeferredTriggers.RemoveAt(0, 1, EAllowShrinking::No);
+    		OwningFlowAsset.TriggerInput(Entry.NodeGuid, Entry.PinName, Entry.FromPin);
+    	}
+    	check(DeferredTriggers.IsEmpty() || FFlowExecutionGate::IsHalted());
+    	// Return true if everything flushed without being interrupted by an ExecutionGate
+    	return DeferredTriggers.IsEmpty();
+    }

Source/Flow/Private/FlowAsset.cpp

            
                      Original file line number
                      Diff line number
                      Diff line change
                  
    @@ -8,6 +8,7 @@
  
    #include "AddOns/FlowNodeAddOn.h"

    #include "Asset/FlowAssetParams.h"

    #include "Asset/FlowAssetParamsUtils.h"

    #include "Interfaces/FlowExecutionGate.h"

    #include "Nodes/FlowNodeBase.h"

    #include "Nodes/Graph/FlowNode_CustomInput.h"

    #include "Nodes/Graph/FlowNode_CustomOutput.h"

    @@ -645,30 +646,34 @@ bool UFlowAsset::TryUpdateManagedFlowPinsForNode(UFlowNode& FlowNode)
  
    			FlowNode.GetAutoInputDataPins(),

    			FlowNode.GetAutoOutputDataPins());

    	// Allow the node to auto-generate data pins

    	FlowNode.AutoGenerateDataPins(WorkingData);

    	bool bAutoInputDataPinsChanged = false;

    	bool bAutoOutputDataPinsChanged = false;

    	// If the auto-generated data pins array changed, it counts as dirty as well

    	const bool bAutoInputDataPinsChanged = WorkingData.DidAutoInputDataPinsChange();

    	const bool bAutoOutputDataPinsChanged = WorkingData.DidAutoOutputDataPinsChange();

    	if (bAutoInputDataPinsChanged || bAutoOutputDataPinsChanged)

    	if (WorkingData.AutoGenerateDataPinsForFlowNode(FlowNode, bAutoInputDataPinsChanged, bAutoOutputDataPinsChanged))

    	{

    		FlowNode.SetFlags(RF_Transactional);

    		FlowNode.Modify();

    		// Lock-in the data that changed.

    		if (bAutoInputDataPinsChanged || bAutoOutputDataPinsChanged)

    		TArray<FFlowPin> FlowPinsNext;

    		const int32 LargestPinNum = FMath::Max(WorkingData.AutoInputDataPinsNext.Num(), WorkingData.AutoOutputDataPinsNext.Num());

    		if (bAutoInputDataPinsChanged)

    		{

    			if (bAutoInputDataPinsChanged)

    			{

    				FlowNode.SetAutoInputDataPins(WorkingData.AutoInputDataPinsNext);

    			}

    			FlowPinsNext.Reserve(LargestPinNum);

    			if (bAutoOutputDataPinsChanged)

    			{

    				FlowNode.SetAutoOutputDataPins(WorkingData.AutoOutputDataPinsNext);

    			}

    			WorkingData.BuildNextFlowPinArray(WorkingData.AutoInputDataPinsNext, FlowPinsNext);

    			FlowNode.SetAutoInputDataPins(FlowPinsNext);

    		}

    		if (bAutoOutputDataPinsChanged)

    		{

    			FlowPinsNext.Reserve(LargestPinNum);

    			WorkingData.BuildNextFlowPinArray(WorkingData.AutoOutputDataPinsNext, FlowPinsNext);

    			FlowNode.SetAutoOutputDataPins(FlowPinsNext);

    		}

    		FlowNode.PostEditChange();

    @@ -970,6 +975,9 @@ void UFlowAsset::InitializeInstance(const TWeakObjectPtr<UObject> InOwner, UFlow
  
    void UFlowAsset::DeinitializeInstance()

    {

    	// These should have been flushed in FinishFlow()

    	check(DeferredTransitionScopes.IsEmpty());

    	if (IsInstanceInitialized())

    	{

    		for (const TPair<FGuid, UFlowNode*>& Node : ObjectPtrDecay(Nodes))

    @@ -1012,6 +1020,11 @@ void UFlowAsset::PreStartFlow()
  
    void UFlowAsset::StartFlow(IFlowDataPinValueSupplierInterface* DataPinValueSupplier)

    {

    	if (FFlowExecutionGate::IsHalted())

    	{

    		return;

    	}

    	PreStartFlow();

    	if (UFlowNode* ConnectedEntryNode = GetDefaultEntryNode())

    @@ -1031,6 +1044,8 @@ void UFlowAsset::FinishFlow(const EFlowFinishPolicy InFinishPolicy, const bool b
  
    {

    	FinishPolicy = InFinishPolicy;

    	CancelAndWarnForUnflushedDeferredTriggers();

    	// end execution of this asset and all of its nodes

    	for (UFlowNode* Node : ActiveNodes)

    	{

    @@ -1052,6 +1067,62 @@ void UFlowAsset::FinishFlow(const EFlowFinishPolicy InFinishPolicy, const bool b
  
    	}

    }

    void UFlowAsset::CancelAndWarnForUnflushedDeferredTriggers()

    {

    	// Aggressively drop any pending deferred triggers — graph is done

    	// In normal execution these should have been flushed via PopDeferredTransitionScope() in TriggerInputDirect

    	// In the debugger they should have been flushed by ResumePIE

    	// Remaining scopes here usually mean:

    	//   - early/abnormal termination (e.g. FinishFlow called from unexpected place)

    	//   - exception/early return before Pop

    	//   - forced deinitialization during active execution (e.g. PIE stop, subsystem cleanup)

    	if (!DeferredTransitionScopes.IsEmpty())

    	{

    		int32 TotalDroppedTriggers = 0;

    		for (const TSharedPtr<FFlowDeferredTransitionScope>& ScopePtr : DeferredTransitionScopes)

    		{

    			if (!ScopePtr.IsValid())

    			{

    				continue;

    			}

    			const TArray<FFlowDeferredTriggerInput>& Triggers = ScopePtr->GetDeferredTriggers();

    			if (TotalDroppedTriggers == 0 && !Triggers.IsEmpty())

    			{

    				UE_LOG(LogFlow, Warning, TEXT("FlowAsset '%s' is finishing with %d lingering deferred transition scope(s) — dropping them. "

    					"This is usually unexpected and may indicate a bug or abnormal termination."),

    					*GetName(), DeferredTransitionScopes.Num());

    			}

    			TotalDroppedTriggers += Triggers.Num();

    			for (const FFlowDeferredTriggerInput& Trigger : Triggers)

    			{

    				const UFlowNode* ToNode = GetNode(Trigger.NodeGuid);

    				const UFlowNode* FromNode = Trigger.FromPin.NodeGuid.IsValid() ? GetNode(Trigger.FromPin.NodeGuid) : nullptr;

    				UE_LOG(LogFlow, Error,

    					TEXT("  → Dropped deferred trigger:\n")

    					TEXT("      To Node: %s (%s)\n")

    					TEXT("      To Pin:  %s\n")

    					TEXT("      From Node: %s (%s)\n")

    					TEXT("      From Pin:  %s"),

    					*ToNode->GetName(),

    					*Trigger.NodeGuid.ToString(),

    					*Trigger.PinName.ToString(),

    					*FromNode->GetName(),

    					*Trigger.FromPin.NodeGuid.ToString(),

    					*Trigger.FromPin.PinName.ToString()

    				);

    			}

    		}

    		ClearAllDeferredTriggerScopes();

    	}

    }

    bool UFlowAsset::HasStartedFlow() const

    {

    	return RecordedNodes.Num() > 0;

    @@ -1126,6 +1197,34 @@ void UFlowAsset::TriggerCustomOutput(const FName& EventName)
  
    }

    void UFlowAsset::TriggerInput(const FGuid& NodeGuid, const FName& PinName, const FConnectedPin& FromPin)

    {

    	if (ShouldDeferTriggersForDebugger())

    	{

    		EnqueueDeferredTrigger(NodeGuid, PinName, FromPin);

    	}

    	else if (ShouldUseStandardDeferTriggers())

    	{

    		// Defer only if we have an open top scope

    		if (!DeferredTransitionScopes.IsEmpty() && DeferredTransitionScopes.Top()->IsOpen())

    		{

    			EnqueueDeferredTrigger(NodeGuid, PinName, FromPin);

    		}

    		else

    		{

    			const TSharedPtr<FFlowDeferredTransitionScope> CurScope = PushDeferredTransitionScope();

    			TriggerInputDirect(NodeGuid, PinName, FromPin);

    			PopDeferredTransitionScope(CurScope);

    		}

    	}

    	else

    	{

    		TriggerInputDirect(NodeGuid, PinName, FromPin);

    	}

    }

    void UFlowAsset::TriggerInputDirect(const FGuid& NodeGuid, const FName& PinName, const FConnectedPin& FromPin)

    {

    	if (UFlowNode* Node = Nodes.FindRef(NodeGuid))

    	{

    @@ -1139,6 +1238,86 @@ void UFlowAsset::TriggerInput(const FGuid& NodeGuid, const FName& PinName, const
  
    	}

    }

    bool UFlowAsset::ShouldDeferTriggersForDebugger() const

    {

    	// Halt always takes precedence for debugger correctness

    	return FFlowExecutionGate::IsHalted();

    }

    bool UFlowAsset::ShouldUseStandardDeferTriggers() const

    {

    	return UFlowSettings::Get()->bDeferTriggeredOutputsWhileTriggering;

    }

    TSharedPtr<FFlowDeferredTransitionScope> UFlowAsset::PushDeferredTransitionScope()

    {

    	// Close the former top scope (if any)

    	if (!DeferredTransitionScopes.IsEmpty())

    	{

    		const TSharedPtr<FFlowDeferredTransitionScope>& FormerTop = DeferredTransitionScopes.Top();

    		FormerTop->CloseScope();

    	}

    	// Push a fresh open scope

    	return DeferredTransitionScopes.Add_GetRef(MakeShared<FFlowDeferredTransitionScope>());

    }

    bool UFlowAsset::TryFlushAndRemoveDeferredTransitionScope(const TSharedPtr<FFlowDeferredTransitionScope>& ScopeToFlush)

    {

    	if (ScopeToFlush->TryFlushDeferredTriggers(*this))

    	{

    		// Remove the exact instance we were holding (handles nested push/pop cases)

    		DeferredTransitionScopes.RemoveSingle(ScopeToFlush);

    		return true;

    	}

    	else

    	{

    		// Flush was interrupted — should only happen due to execution gate halt

    		check(FFlowExecutionGate::IsHalted());

    		return false;

    	}

    }

    void UFlowAsset::EnqueueDeferredTrigger(const FGuid& NodeGuid, const FName& PinName, const FConnectedPin& FromPin)

    {

    	if (DeferredTransitionScopes.IsEmpty() || !DeferredTransitionScopes.Top()->IsOpen())

    	{

    		// This should only occur when halted at an execution gate

    		check(FFlowExecutionGate::IsHalted());

    		PushDeferredTransitionScope();

    	}

    	// Always enqueue to the current innermost (top) scope

    	DeferredTransitionScopes.Top()->EnqueueDeferredTrigger(FFlowDeferredTriggerInput{ NodeGuid, PinName, FromPin });

    }

    bool UFlowAsset::TryFlushAllDeferredTriggerScopes()

    {

    	while (const TSharedPtr<FFlowDeferredTransitionScope> TopScope = GetTopDeferredTransitionScope())

    	{

    		if (!TryFlushAndRemoveDeferredTransitionScope(TopScope))

    		{

    			break;

    		}

    		// Keep flushing until stack is empty or we hit an ExecutionGate halt

    	}

    	check(DeferredTransitionScopes.IsEmpty() || FFlowExecutionGate::IsHalted());

    	return DeferredTransitionScopes.IsEmpty();

    }

    void UFlowAsset::ClearAllDeferredTriggerScopes()

    {

    	DeferredTransitionScopes.Reset();

    }

    TSharedPtr<FFlowDeferredTransitionScope> UFlowAsset::GetTopDeferredTransitionScope() const

    {

    	return !DeferredTransitionScopes.IsEmpty() ? DeferredTransitionScopes.Top() : nullptr;

    }

    void UFlowAsset::FinishNode(UFlowNode* Node)

    {

    	if (ActiveNodes.Contains(Node))

Source/Flow/Private/FlowSettings.cpp

-Original file line number
+Diff line change
@@ Expand Up @@
     	, bWarnAboutMissingIdentityTags(true)
     	, bLogOnSignalDisabled(true)
     	, bLogOnSignalPassthrough(true)
+    	, bDeferTriggeredOutputsWhileTriggering(true)
     	, bUseAdaptiveNodeTitles(false)
     	, DefaultExpectedOwnerClass(UFlowComponent::StaticClass())
     {
@@ Expand Down @@

Source/Flow/Private/FlowSubsystem.cpp

-Original file line number
+Diff line change
@@ Expand Up / @@ -7,6 +7,7 @@ @@
     #include "FlowLogChannels.h"
     #include "FlowSave.h"
     #include "FlowSettings.h"
+    #include "Interfaces/FlowExecutionGate.h"
     #include "Nodes/Graph/FlowNode_SubGraph.h"
     #include "Engine/GameInstance.h"
@@ Expand Down Expand Up @@
     	}
     }
+    bool UFlowSubsystem::TryFlushAllDeferredTriggerScopes()
+    {
+    	// Flush deferred triggers on all active runtime instances.
+    	// Flush order follows InstancedTemplates iteration + per-template ActiveInstances.
+    	// This provides reasonable per-asset FIFO but is not a strict global FIFO across assets.
+    	// A more precise global queue could be implemented later if cross-asset ordering becomes critical.
+    	const TArray<UFlowAsset*> CapturedInstancedTemplates = InstancedTemplates;
+    	for (UFlowAsset* Template : CapturedInstancedTemplates)
+    	{
+    		if (!IsValid(Template))
+    		{
+    			continue;
+    		}
+    		for (UFlowAsset* Instance : Template->GetActiveInstances())
+    		{
+    			if (FFlowExecutionGate::IsHalted())
+    			{
+    				break;
+    			}
+    			if (IsValid(Instance))
+    			{
+    				const bool bFlushed = Instance->TryFlushAllDeferredTriggerScopes();
+    				// The only case where we allow a flush to stop before completing
+    				// is if we hit an execution gate halt
+    				check(bFlushed || FFlowExecutionGate::IsHalted());
+    			}
+    		}
+    	}
+    	// The only case where we allow a flush to stop before completing
+    	// is if we hit an execution gate halt
+    	const bool bCompletedFlushAll = !FFlowExecutionGate::IsHalted();
+    	return bCompletedFlushAll;
+    }
+    void UFlowSubsystem::ClearAllDeferredTriggerScopes()
+    {
+    	for (UFlowAsset* Template : InstancedTemplates)
+    	{
+    		if (!IsValid(Template))
+    		{
+    			continue;
+    		}
+    		for (UFlowAsset* Instance : Template->GetActiveInstances())
+    		{
+    			if (IsValid(Instance))
+    			{
+    				Instance->ClearAllDeferredTriggerScopes();
+    			}
+    		}
+    	}
+    }
     UFlowAsset* UFlowSubsystem::CreateSubFlow(UFlowNode_SubGraph* SubGraphNode, const FString& SavedInstanceName, const bool bPreloading /* = false */)
     {
     	UFlowAsset* NewInstance = nullptr;
@@ Expand Down @@

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