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FStateTreeExecutionContext

StateTree Execution Context is a helper that is used to update StateTree instance data.

API > API/Plugins > API/Plugins/StateTreeModule

StateTree Execution Context is a helper that is used to update StateTree instance data.

The context is meant to be temporary, you should not store a context across multiple frames.

The owner is used as the owner of the instantiated UObjects in the instance data and logging, it should have same or greater lifetime as the InstanceData.

In common case you can use the constructor to initialize the context, and us a helper struct to set up the context data and external data getter: FStateTreeExecutionContext Context(*GetOwner(), *StateTreeRef.GetStateTree(), InstanceData); if (SetContextRequirements(Context)) { Context.Tick(DeltaTime); }

bool UMyComponent::SetContextRequirements(FStateTreeExecutionContext& Context) { if (!Context.IsValid()) { return false; } // Setup context data Context.SetContextDataByName(...); ...

Context.SetCollectExternalDataCallback(FOnCollectStateTreeExternalData::CreateUObject(this, &UMyComponent::CollectExternalData);

return Context.AreContextDataViewsValid(); }

bool UMyComponent::CollectExternalData(const FStateTreeExecutionContext& Context, const UStateTree* StateTree, TArrayView ExternalDataDescs, TArrayView OutDataViews) { ... for (int32 Index = 0; Index < ExternalDataDescs.Num(); Index++) { const FStateTreeExternalDataDesc& Desc = ExternalDataDescs[Index]; if (Desc.Struct->IsChildOf(UWorldSubsystem::StaticClass())) { UWorldSubsystem* Subsystem = World->GetSubsystemBase(Cast(const_cast(Desc.Struct.Get()))); OutDataViews[Index] = FStateTreeDataView(Subsystem); } ... } return true; }

In this example the SetContextRequirements() method is used to set the context defined in the schema, and the delegate FOnCollectStateTreeExternalData is used to query the external data required by the tasks and conditions.

In case the State Tree links to other state tree assets, the collect external data might get called multiple times, once for each asset.

   
Name FStateTreeExecutionContext
Type struct
Header File /Engine/Plugins/Runtime/StateTree/Source/StateTreeModule/Public/StateTreeExecutionContext.h
Include Path #include "StateTreeExecutionContext.h"

Syntax

struct FStateTreeExecutionContext : public FStateTreeMinimalExecutionContext

Inheritance Hierarchy

Derived Classes

Constructors

Name Remarks Include Path Unreal Specifiers

FStateTreeExecutionContext ( TNotNull< UObject* > Owner,
TNotNull< const UStateTree* > StateTree,
FStateTreeInstanceData& InInstanceData,
const FOnCollectStateTreeExternalData& CollectExternalDataCallback,
const EStateTreeRecordTransitions RecordTransitions
)

   StateTreeExecutionContext.h  

FStateTreeExecutionContext ( UObject& InOwner,
const UStateTree& InStateTree,
FStateTreeInstanceData& InInstanceData,
const FOnCollectStateTreeExternalData& CollectExternalDataCallback,
const EStateTreeRecordTransitions RecordTransitions
)

 FStateTreeExecutionContext implementation StateTreeExecutionContext.h  

FStateTreeExecutionContext ( const FStateTreeExecutionContext& InContextToCopy,
TNotNull< const UStateTree* > StateTree,
FStateTreeInstanceData& InInstanceData
)

 Construct an execution context from a parent context and another tree. StateTreeExecutionContext.h  

FStateTreeExecutionContext ( const FStateTreeExecutionContext& InContextToCopy,
const UStateTree& InStateTree,
FStateTreeInstanceData& InInstanceData
)

 Construct an execution context from a parent context and another tree. StateTreeExecutionContext.h  
  StateTreeExecutionContext.h  

Destructors

Name Remarks Include Path Unreal Specifiers

virtual ~FStateTreeExecutionContext()

   StateTreeExecutionContext.h  

Structs

Name Remarks
FAllowDirectTransitionsScope Helper struct to track when it is allowed to request transitions.
FCollectedExternalDataCache  
FCurrentFrameStateSelectionEventsScope Helper struct to track currently processed state selection events.
FCurrentlyProcessedFrameScope Helper struct to track currently processed frame.
FCurrentlyProcessedStateScope Helper struct to track currently processed state.
FCurrentlyProcessedTransitionEventScope Helper struct to track currently processed transition event.
FExternalGlobalParameters Structure to-be-populated and set for any StateTree using any EStateTreeDataSourceType::ExternalGlobalParameterData bindings
FNodeInstanceDataScope Helper struct to set current node data.
FStartParameters  
FStateSelectionResult Describes a result of States Selection.
FTickTaskArguments  
FTickTaskResult  

Functions

Public

Name Remarks Include Path Unreal Specifiers

bool AddDelegateListener ( const FStateTreeDelegateListener& Listener,
FSimpleDelegate Delegate
)

 Adds delegate listener. StateTreeExecutionContext.h  

bool AreContextDataViewsValid()

   StateTreeExecutionContext.h  

void BindDelegate ( const FStateTreeDelegateListener& Listener,
FSimpleDelegate Delegate
)

 Registers the delegate to the listener. StateTreeExecutionContext.h  

void BroadcastDelegate ( const FStateTreeDelegateDispatcher& Dispatcher
)

 Broadcasts the delegate. StateTreeExecutionContext.h  

void ConsumeEvent ( const FStateTreeSharedEvent& Event
)

 Consumes and removes the specified event from the event queue. StateTreeExecutionContext.h  

PRAGMA_DISABLE_DEPRECATION_WARNINGS void FinishTask ( const UE::StateTree::FFinishedTask& Task,
EStateTreeFinishTaskType FinishType
)

 Finishes a task. StateTreeExecutionContext.h  

void FinishTask ( const FStateTreeTaskBase& Task,
EStateTreeFinishTaskType FinishType
)

 Finishes a task. StateTreeExecutionContext.h  
Forces transition to a state from a previously recorded state tree transition result. StateTreeExecutionContext.h  

TEnableIf< TIsInvocable< TFunc, FStateTreeSharedEvent >::Value, void >::Type ForEachEvent ( TFunc&& Function
) const

 Iterates over all events. StateTreeExecutionContext.h  

TEnableIf< TIsInvocable< TFunc, FStateTreeEvent >::Value, void >::Type ForEachEvent ( TFunc&& Function
) const

 Iterates over all events. StateTreeExecutionContext.h  

FStateTreeDataView GetContextDataByName ( const FName Name
) const

   StateTreeExecutionContext.h  

TConstArrayView< FStateTreeExternalDataDesc > GetContextDataDescs()

   StateTreeExecutionContext.h  

const FStateTreeExecutionFrame * GetCurrentlyProcessedFrame()

   StateTreeExecutionContext.h  

FStateTreeDataHandle GetCurrentlyProcessedNode()

   StateTreeExecutionContext.h  

FStateTreeIndex16 GetCurrentlyProcessedNodeIndex()

   StateTreeExecutionContext.h  

FStateTreeDataHandle GetCurrentlyProcessedNodeInstanceData()

   StateTreeExecutionContext.h  

const FStateTreeExecutionFrame * GetCurrentlyProcessedParentFrame()

   StateTreeExecutionContext.h  

FStateTreeStateHandle GetCurrentlyProcessedState()

   StateTreeExecutionContext.h  

const FStateTreeEventQueue & GetEventQueue()

   StateTreeExecutionContext.h  

TConstArrayView< FStateTreeEvent > GetEventsToProcess()

   StateTreeExecutionContext.h  

TConstArrayView< FStateTreeSharedEvent > GetEventsToProcessView()

   StateTreeExecutionContext.h  

T::DataType & GetExternalData ( const T Handle
) const

 Returns reference to external data based on provided handle. StateTreeExecutionContext.h  

T::DataType * GetExternalDataPtr ( const T Handle
) const

 Returns pointer to external data based on provided item handle. StateTreeExecutionContext.h  

FStateTreeDataView GetExternalDataView ( const FStateTreeExternalDataHandle Handle
)

   StateTreeExecutionContext.h  
  StateTreeExecutionContext.h  

T & GetInstanceData ( const FStateTreeNodeBase& Node
) const

   StateTreeExecutionContext.h  

T::FInstanceDataType & GetInstanceData ( const T& Node
) const

   StateTreeExecutionContext.h  

T * GetInstanceDataPtr ( const FStateTreeNodeBase& Node
) const

   StateTreeExecutionContext.h  

TStateTreeInstanceDataStructRef< typename T::FInstanceDataType > GetInstanceDataStructRef ( const T& Node
) const

   StateTreeExecutionContext.h  

const FStateTreeReference * GetLinkedStateTreeOverrideForTag ( const FGameplayTag StateTag
) const

   StateTreeExecutionContext.h  

FStateTreeEventQueue & GetMutableEventQueue()

   StateTreeExecutionContext.h  

TArrayView< FStateTreeSharedEvent > GetMutableEventsToProcessView()

   StateTreeExecutionContext.h  

FStateTreeInstanceData * GetMutableInstanceData()

   StateTreeExecutionContext.h  

TConstArrayView< FRecordedStateTreeTransitionResult > GetRecordedTransitions()

 Returns the recorded transitions for this context. StateTreeExecutionContext.h  

FStateTreeWeakExecutionContext MakeWeakExecutionContext()

   StateTreeExecutionContext.h  

PRAGMA_DISABLE_DEPRECATION_WARNINGS FStateTreeWeakTaskRef MakeWeakTaskRef ( const FStateTreeTaskBase& Node
) const

 Similar to GetInstanceData, the node needs to be the current processing node. StateTreeExecutionContext.h  

PRAGMA_DISABLE_DEPRECATION_WARNINGS FStateTreeWeakTaskRef MakeWeakTaskRefFromInstanceData ( const T& InInstanceData
) const

 Similar to GetInstanceData, the instance data needs to be the current processing node. StateTreeExecutionContext.h  

PRAGMA_DISABLE_DEPRECATION_WARNINGS FStateTreeWeakTaskRef MakeWeakTaskRefFromInstanceDataPtr ( const T* InInstanceData
) const

 Similar to GetInstanceData, the instance data needs to be the current processing node. StateTreeExecutionContext.h  

void RemoveDelegateListener ( const FStateTreeDelegateListener& Listener
)

 Removes delegate listener. StateTreeExecutionContext.h  
Requests transition to a state. StateTreeExecutionContext.h  
Requests transition to a state. StateTreeExecutionContext.h  

void SetCollectExternalDataCallback ( const FOnCollectStateTreeExternalData& Callback
)

 Sets callback used to collect external data views during State Tree execution. StateTreeExecutionContext.h  

void SetContextData ( const FStateTreeExternalDataHandle Handle,
FStateTreeDataView DataView
)

 Sets context data view value for specific item. StateTreeExecutionContext.h  

bool SetContextDataByName ( const FName Name,
FStateTreeDataView DataView
)

 Sets the context data based on name (name is defined in the schema), returns true if data was found StateTreeExecutionContext.h  

void SetExternalGlobalParameters ( const FExternalGlobalParameters* Parameters
)

   StateTreeExecutionContext.h  

void SetLinkedStateTreeOverrides ( const FStateTreeReferenceOverrides* InLinkedStateTreeOverrides
)

 Overrides for linked State Trees. StateTreeExecutionContext.h  

void SetLinkedStateTreeOverrides ( FStateTreeReferenceOverrides InLinkedStateTreeOverrides
)

 Overrides for linked State Trees. StateTreeExecutionContext.h  
Start executing. StateTreeExecutionContext.h  

EStateTreeRunStatus Start ( const FInstancedPropertyBag* InitialParameters,
int32 RandomSeed
)

 Start executing. StateTreeExecutionContext.h  

EStateTreeRunStatus Stop ( const EStateTreeRunStatus CompletionStatus
)

 Stop executing if the tree is running. StateTreeExecutionContext.h  

EStateTreeRunStatus Tick ( const float DeltaTime
)

 Tick the state tree logic, updates the tasks and triggers transitions. StateTreeExecutionContext.h  
Tick the state tree logic partially, triggers the transitions. StateTreeExecutionContext.h  

EStateTreeRunStatus TickUpdateTasks ( const float DeltaTime
)

 Tick the state tree logic partially, updates the tasks. StateTreeExecutionContext.h  

void UnbindDelegate ( const FStateTreeDelegateListener& Listener
)

 Unregisters the callback bound to the listener. StateTreeExecutionContext.h  

Protected

Name Remarks Include Path Unreal Specifiers

FStateTreeDataView AddTemporaryInstance ( const FStateTreeExecutionFrame& Frame,
const FStateTreeIndex16 OwnerNodeIndex,
const FStateTreeDataHandle DataHandle,
FConstStructView NewInstanceData
)

 Adds a temporary instance that can be located using frame and data handle later. StateTreeExecutionContext.h  

virtual void BeginDelayedTransition ( const FStateTreeTransitionDelayedState& DelayedState
)

 Callback when delayed transition is triggered. StateTreeExecutionContext.h  

void CallStopOnEvaluatorsAndGlobalTasks ( const FStateTreeExecutionFrame* ParentFrame,
const FStateTreeExecutionFrame& Frame,
const FStateTreeTransitionResult& Transition,
const FStateTreeIndex16 LastInitializedTaskIndex
)

 Stops evaluators and global tasks of the given frame. Expects nodes data to be already bound. StateTreeExecutionContext.h  

void CaptureNewStateEvents ( TConstArrayView< FStateTreeExecutionFrame > PrevFrames,
TConstArrayView< FStateTreeExecutionFrame > NewFrames,
TArrayView< FStateTreeFrameStateSelectionEvents > FramesStateSelectionEvents
)

 Captures StateTree events used during the state selection. StateTreeExecutionContext.h  

bool CollectActiveExternalData()

 Collects external data for all StateTrees in active frames. StateTreeExecutionContext.h  
Collects external data for specific State Tree asset. StateTreeExecutionContext.h  

bool CopyBatchOnActiveInstances ( const FStateTreeExecutionFrame* ParentFrame,
const FStateTreeExecutionFrame& CurrentFrame,
const FStateTreeDataView TargetView,
const FStateTreeIndex16 BindingsBatch
)

 Copies a batch of properties to the data in TargetView. StateTreeExecutionContext.h  

bool CopyBatchWithValidation ( const FStateTreeExecutionFrame* ParentFrame,
const FStateTreeExecutionFrame& CurrentFrame,
const FStateTreeDataView TargetView,
const FStateTreeIndex16 BindingsBatch
)

 Copies a batch of properties to the data in TargetView. StateTreeExecutionContext.h  

FString DebugGetEventsAsString()

   StateTreeExecutionContext.h  

FString DebugGetStatePath ( TConstArrayView< FStateTreeExecutionFrame > ActiveFrames,
const FStateTreeExecutionFrame* CurrentFrame,
const int32 ActiveStateIndex
) const

   StateTreeExecutionContext.h  
Handles logic for entering State. StateTreeExecutionContext.h  

void EvaluatePropertyFunctionsOnActiveInstances ( const FStateTreeExecutionFrame* CurrentParentFrame,
const FStateTreeExecutionFrame& CurrentFrame,
FStateTreeIndex16 FuncsBegin,
uint16 FuncsNum
)

 Evaluate all function at given range. StateTreeExecutionContext.h  

void EvaluatePropertyFunctionsWithValidation ( const FStateTreeExecutionFrame* CurrentParentFrame,
const FStateTreeExecutionFrame& CurrentFrame,
FStateTreeIndex16 FuncsBegin,
uint16 FuncsNum
)

 Evaluate all function at given range. StateTreeExecutionContext.h  

float EvaluateUtility ( const FStateTreeExecutionFrame* CurrentParentFrame,
const FStateTreeExecutionFrame& CurrentFrame,
const int32 ConsiderationsOffset,
const int32 ConsiderationsNum,
const float StateWeight
)

 Calculate the final score of all considerations at given range StateTreeExecutionContext.h  

void ExitState ( const FStateTreeTransitionResult& Transition
)

 Handles logic for exiting State. StateTreeExecutionContext.h  
  StateTreeExecutionContext.h  
  StateTreeExecutionContext.h  
  StateTreeExecutionContext.h  
  StateTreeExecutionContext.h  
  StateTreeExecutionContext.h  
  StateTreeExecutionContext.h  

EStateTreeRunStatus GetGlobalTasksCompletedStatesStatus()

 In the list of completed states, returns the run status when it's completed by a global task. StateTreeExecutionContext.h  

virtual FString GetInstanceDescription()

   StateTreeExecutionContext.h  

FString GetSafeStateName ( const FStateTreeExecutionFrame& CurrentFrame,
const FStateTreeStateHandle State
) const

   StateTreeExecutionContext.h  

FString GetStateStatusString ( const FStateTreeExecutionState& ExecState
) const

   StateTreeExecutionContext.h  

FStateTreeDataView GetTemporaryDataView ( const FStateTreeExecutionFrame* ParentFrame,
const FStateTreeExecutionFrame& CurrentFrame,
const FStateTreeDataHandle Handle
)

   StateTreeExecutionContext.h  

PRAGMA_DISABLE_DEPRECATION_WARNINGS bool IsFinishedTaskValid ( const UE::StateTree::FFinishedTask& Task
) const

 Confirms that the frame and state ID are valid and the task index is correct. StateTreeExecutionContext.h  

bool IsHandleSourceValid ( const FStateTreeExecutionFrame* ParentFrame,
const FStateTreeExecutionFrame& CurrentFrame,
const FPropertyBindingCopyInfo& CopyInfo
) const

   StateTreeExecutionContext.h  

bool IsHandleSourceValid ( const FStateTreeExecutionFrame* ParentFrame,
const FStateTreeExecutionFrame& CurrentFrame,
const FStateTreeDataHandle Handle
) const

   StateTreeExecutionContext.h  

FRecordedStateTreeTransitionResult MakeRecordedTransitionResult ( const FStateTreeTransitionResult& Transition
) const

 Create a new recorded transition from a transition result. StateTreeExecutionContext.h  
Create a new transition result from a recorded transition result. StateTreeExecutionContext.h  

PRAGMA_DISABLE_DEPRECATION_WARNINGS FStateTreeWeakTaskRef MakeWeakTaskRefInternal()

   StateTreeExecutionContext.h  

PRAGMA_DISABLE_DEPRECATION_WARNINGS void MarkStateCompleted ( UE::StateTree::FFinishedTask& FinisedTask
)

 Adds the state to the completed list from a finished task. StateTreeExecutionContext.h  

void RemoveAllDelegateListeners()

 Removes all delegate listeners. StateTreeExecutionContext.h  

bool RequestTransition ( const FStateTreeExecutionFrame& CurrentFrame,
const FStateTreeStateHandle NextState,
const EStateTreeTransitionPriority Priority,
const FStateTreeSharedEvent* TransitionEvent,
const EStateTreeSelectionFallback Fallback
)

 Requests transition to a specified state with specified priority. StateTreeExecutionContext.h  

bool SelectState ( const FStateTreeExecutionFrame& CurrentFrame,
const FStateTreeStateHandle NextState,
FStateSelectionResult& OutSelectionResult,
const FStateTreeSharedEvent* TransitionEvent,
const EStateTreeSelectionFallback Fallback
)

 Runs state selection logic starting at the specified state, walking towards the leaf states. StateTreeExecutionContext.h  

bool SelectStateInternal ( const FStateTreeExecutionFrame* CurrentParentFrame,
FStateTreeExecutionFrame& CurrentFrame,
const FStateTreeExecutionFrame* CurrentFrameInActiveFrames,
TConstArrayView< FStateTreeStateHandle > PathToNextState,
FStateSelectionResult& OutSelectionResult,
const FStateTreeSharedEvent* TransitionEvent
)

 Used internally to do the recursive part of the SelectState(). StateTreeExecutionContext.h  

bool SetGlobalParameters ( const FInstancedPropertyBag& Parameters
)

 Stores copy of provided parameters as State Tree global parameters. StateTreeExecutionContext.h  

void SetUpdatePhaseInExecutionState ( FStateTreeExecutionState& ExecutionState,
EStateTreeUpdatePhase UpdatePhase
) const

 Updates the update phase of the statetree execution state. StateTreeExecutionContext.h  

void SetupNextTransition ( const FStateTreeExecutionFrame& CurrentFrame,
const FStateTreeStateHandle NextState,
const EStateTreeTransitionPriority Priority
)

 Sets up NextTransition based on the provided parameters and the current execution status. StateTreeExecutionContext.h  

EStateTreeRunStatus StartEvaluatorsAndGlobalTasks ( FStateTreeIndex16& OutLastInitializedTaskIndex
)

 Starts evaluators and global tasks. StateTreeExecutionContext.h  
  StateTreeExecutionContext.h  
Starts temporary instances of global evaluators and tasks for a given frame. StateTreeExecutionContext.h  

void StateCompleted ()

 Handles logic for signaling State completed. StateTreeExecutionContext.h  

void StopEvaluatorsAndGlobalTasks ( const EStateTreeRunStatus CompletionStatus,
const FStateTreeIndex16 LastInitializedTaskIndex
)

 Stops evaluators and global tasks. StateTreeExecutionContext.h  

void StopTemporaryEvaluatorsAndGlobalTasks ( const FStateTreeExecutionFrame* CurrentParentFrame,
const FStateTreeExecutionFrame& CurrentFrame
)

 Stops temporary global evaluators and tasks for the provided frame. StateTreeExecutionContext.h  

bool TestAllConditions ( const FStateTreeExecutionFrame* CurrentParentFrame,
const FStateTreeExecutionFrame& CurrentFrame,
const int32 ConditionsOffset,
const int32 ConditionsNum
)

 Checks all conditions at given range StateTreeExecutionContext.h  

EStateTreeRunStatus TickEvaluatorsAndGlobalTasks ( const float DeltaTime,
bool bTickGlobalTasks
)

 Tick evaluators and global tasks by delta time. StateTreeExecutionContext.h  

EStateTreeRunStatus TickEvaluatorsAndGlobalTasksForFrame ( const float DeltaTime,
const bool bTickGlobalTasks,
const int32 FrameIndex,
const FStateTreeExecutionFrame* CurrentParentFrame,
const TNotNull< FStateTreeExecutionFrame* > CurrentFrame
)

 Tick evaluators and global tasks of a specific frame. StateTreeExecutionContext.h  

EStateTreeRunStatus TickPostlude()

   StateTreeExecutionContext.h  

EStateTreeRunStatus TickPrelude()

 Common functionality shared by the tick methods. StateTreeExecutionContext.h  

EStateTreeRunStatus TickTasks ( const float DeltaTime
)

 Ticks tasks of all active states starting from current state by delta time. StateTreeExecutionContext.h  
Ticks tasks and updates the bindings for a specific state or frame. StateTreeExecutionContext.h  

void TickTriggerTransitionsInternal()

 Handles transition triggering part of the tick. StateTreeExecutionContext.h  

void TickUpdateTasksInternal ( float DeltaTime
)

 Handles task ticking part of the tick. StateTreeExecutionContext.h  
Triggers transitions based on current run status. StateTreeExecutionContext.h  
  StateTreeExecutionContext.h  

void UpdateCompletedStateList ( bool bMarkTaskProcessed
)

 Removes stale entries and fills the completed states list. StateTreeExecutionContext.h  

void UpdateInstanceData ( TConstArrayView< FStateTreeExecutionFrame > CurrentActiveFrames,
TArrayView< FStateTreeExecutionFrame > NextActiveFrames
)

   StateTreeExecutionContext.h  

Static

Name Remarks Include Path Unreal Specifiers

static const FStateTreeExecutionFrame * FindFrame ( const UStateTree* StateTree,
FStateTreeStateHandle RootState,
TConstArrayView< FStateTreeExecutionFrame > Frames,
const FStateTreeExecutionFrame*& OutParentFrame
)

 Looks for a frame in provided list of frames. StateTreeExecutionContext.h  

static FStateTreeDataView GetDataView ( FStateTreeInstanceStorage& InstanceDataStorage,
FStateTreeInstanceStorage* CurrentlyProcessedSharedInstanceStorage,
const FStateTreeExecutionFrame* ParentFrame,
const FStateTreeExecutionFrame& CurrentFrame,
TConstArrayView< FStateTreeDataView > ContextAndExternalDataViews,
const FStateTreeDataHandle Handle
)

   StateTreeExecutionContext.h  

static FStateTreeDataView GetDataViewFromInstanceStorage ( FStateTreeInstanceStorage& InstanceDataStorage,
FStateTreeInstanceStorage* CurrentlyProcessedSharedInstanceStorage,
const FStateTreeExecutionFrame* ParentFrame,
const FStateTreeExecutionFrame& CurrentFrame,
const FStateTreeDataHandle Handle
)

   StateTreeExecutionContext.h  

Operators

Name Remarks Include Path Unreal Specifiers
  StateTreeExecutionContext.h  

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