C++ UProperty类代码示例

/**
 * Finds a child property node from the provided parent node (does not recurse into grandchildren)
 *
 * @param InParentNode	The parent node to locate the child from
 * @param PropertyName	The property name to find
 * @param Index			The index of the property if its in an array
 */
static TSharedPtr<FPropertyNode> FindChildPropertyNode( FPropertyNode& InParentNode, const FString& PropertyName, int32 Index )
{
	TSharedPtr<FPropertyNode> FoundNode(NULL);

	// search each child for a property with the provided name
	for( int32 ChildIndex = 0; ChildIndex < InParentNode.GetNumChildNodes(); ++ChildIndex )
	{
		TSharedPtr<FPropertyNode>& ChildNode = InParentNode.GetChildNode(ChildIndex);
		UProperty* Property = ChildNode->GetProperty();
		if( Property && Property->GetFName() == *PropertyName )
		{
			FoundNode = ChildNode;
			break;
		}
	}

	// Find the array element.
	if( FoundNode.IsValid() && Index != INDEX_NONE )
	{
		// The found node is the top array so get its child which is the actual node
		FoundNode = FoundNode->GetChildNode( Index );
	}

	return FoundNode;
}

bool FDetailWidgetExtensionHandler::IsPropertyExtendable(const UClass* InObjectClass, const IPropertyHandle& InPropertyHandle) const
{
	// TODO UMG make this work for multiple widgets.
	if ( InPropertyHandle.GetNumOuterObjects() == 1 )
	{
		TArray<UObject*> Objects;
		InPropertyHandle.GetOuterObjects(Objects);

		// We don't allow bindings on the CDO.
		if ( Objects[0]->HasAnyFlags(RF_ClassDefaultObject) )
		{
			return false;
		}

		UProperty* Property = InPropertyHandle.GetProperty();
		FString DelegateName = Property->GetName() + "Delegate";

		if ( UClass* ContainerClass = Cast<UClass>(Property->GetOuter()) )
		{
			UDelegateProperty* DelegateProperty = FindField<UDelegateProperty>(ContainerClass, FName(*DelegateName));
			if ( DelegateProperty )
			{
				return true;
			}
		}
	}

	return false;
}

void UUserDefinedStructEditorData::RecreateDefaultInstance(FString* OutLog)
{
	UStruct* ScriptStruct = GetOwnerStruct();
	DefaultStructInstance.Recreate(ScriptStruct);
	uint8* StructData = DefaultStructInstance.GetStructMemory();
	ensure(DefaultStructInstance.IsValid() && DefaultStructInstance.GetStruct() == ScriptStruct);
	if (DefaultStructInstance.IsValid() && StructData && ScriptStruct)
	{
		DefaultStructInstance.SetPackage(ScriptStruct->GetOutermost());

		for (TFieldIterator<UProperty> It(ScriptStruct); It; ++It)
		{
			UProperty* Property = *It;
			if (Property)
			{
				auto VarDesc = VariablesDescriptions.FindByPredicate(FStructureEditorUtils::FFindByNameHelper<FStructVariableDescription>(Property->GetFName()));
				if (VarDesc && !VarDesc->CurrentDefaultValue.IsEmpty())
				{
					if (!FBlueprintEditorUtils::PropertyValueFromString(Property, VarDesc->CurrentDefaultValue, StructData))
					{
						const FString Message = FString::Printf(TEXT("Cannot parse value. Property: %s String: \"%s\" ")
							, (Property ? *Property->GetDisplayNameText().ToString() : TEXT("None"))
							, *VarDesc->CurrentDefaultValue);
						UE_LOG(LogClass, Warning, TEXT("UUserDefinedStructEditorData::RecreateDefaultInstance %s Struct: %s "), *Message, *GetPathNameSafe(ScriptStruct));
						if (OutLog)
						{
							OutLog->Append(Message);
						}
					}
				}
			}
		}
	}
}

void UCanvasPanelSlot::PostEditChangeChainProperty(struct FPropertyChangedChainEvent& PropertyChangedEvent)
{
	SynchronizeProperties();

	static FName AnchorsProperty(TEXT("Anchors"));

	FEditPropertyChain::TDoubleLinkedListNode* AnchorNode = PropertyChangedEvent.PropertyChain.GetHead()->GetNextNode();
	if ( !AnchorNode )
	{
		return;
	}

	FEditPropertyChain::TDoubleLinkedListNode* LayoutDataNode = AnchorNode->GetNextNode();

	if ( !LayoutDataNode )
	{
		return;
	}

	UProperty* AnchorProperty = LayoutDataNode->GetValue();

	if ( AnchorProperty && AnchorProperty->GetFName() == AnchorsProperty )
	{
		RebaseLayout();
	}

	Super::PostEditChangeProperty(PropertyChangedEvent);
}

/** Finds a property by name, starting in the specified scope; Validates property type and returns NULL along with emitting an error if there is a mismatch. */
UProperty* FKismetCompilerUtilities::FindPropertyInScope(UStruct* Scope, UEdGraphPin* Pin, FCompilerResultsLog& MessageLog, const UEdGraphSchema_K2* Schema, UClass* SelfClass)
{
	while (Scope != NULL)
	{
		for (TFieldIterator<UProperty> It(Scope, EFieldIteratorFlags::IncludeSuper); It; ++It)
		{
			UProperty* Property = *It;

			if (Property->GetName() == Pin->PinName)
			{
				if (FKismetCompilerUtilities::IsTypeCompatibleWithProperty(Pin, Property, MessageLog, Schema, SelfClass))
				{
					return Property;
				}
				else
				{
					// Exit now, we found one with the right name but the type mismatched (and there was a type mismatch error)
					return NULL;
				}
			}
		}

		// Functions don't automatically check their class when using a field iterator
		UFunction* Function = Cast<UFunction>(Scope);
		Scope = (Function != NULL) ? Cast<UStruct>(Function->GetOuter()) : NULL;
	}

	// Couldn't find the name
	MessageLog.Error(*LOCTEXT("PropertyNotFound_Error", "The property associated with @@ could not be found").ToString(), Pin);
	return NULL;
}

void FNodeHandlingFunctor::ResolveAndRegisterScopedTerm(FKismetFunctionContext& Context, UEdGraphPin* Net, TIndirectArray<FBPTerminal>& NetArray)
{
	// Determine the scope this takes place in
	UStruct* SearchScope = Context.Function;

	UEdGraphPin* SelfPin = CompilerContext.GetSchema()->FindSelfPin(*(Net->GetOwningNode()), EGPD_Input);
	if (SelfPin != NULL)
	{
		SearchScope = Context.GetScopeFromPinType(SelfPin->PinType, Context.NewClass);
	}

	// Find the variable in the search scope
	UProperty* BoundProperty = FKismetCompilerUtilities::FindPropertyInScope(SearchScope, Net, CompilerContext.MessageLog, CompilerContext.GetSchema(), Context.NewClass);
	if (BoundProperty != NULL)
	{
		// Create the term in the list
		FBPTerminal* Term = new (NetArray) FBPTerminal();
		Term->CopyFromPin(Net, Net->PinName);
		Term->AssociatedVarProperty = BoundProperty;
		Context.NetMap.Add(Net, Term);

		// Read-only variables and variables in const classes are both const
		if (BoundProperty->HasAnyPropertyFlags(CPF_BlueprintReadOnly) || Context.IsConstFunction())
		{
			Term->bIsConst = true;
		}

		// Resolve the context term
		if (SelfPin != NULL)
		{
			FBPTerminal** pContextTerm = Context.NetMap.Find(FEdGraphUtilities::GetNetFromPin(SelfPin));
			Term->Context = (pContextTerm != NULL) ? *pContextTerm : NULL;
		}
	}
}

void UGatherTextFromMetaDataCommandlet::GatherTextFromUObjects(const TArray<FString>& IncludePaths, const TArray<FString>& ExcludePaths, const FGatherParameters& Arguments)
{
	const FFuzzyPathMatcher FuzzyPathMatcher = FFuzzyPathMatcher(IncludePaths, ExcludePaths);

	for(TObjectIterator<UField> It; It; ++It)
	{
		// Skip editor-only properties if we're not gathering for editor-only data.
		UProperty* Property = Cast<UProperty>(*It);
		if (Property && !ShouldGatherFromEditorOnlyData && Property->HasAnyPropertyFlags(CPF_EditorOnly))
		{
			continue;
		}

		FString SourceFilePath;
		FSourceCodeNavigation::FindClassHeaderPath(*It, SourceFilePath);
		SourceFilePath = FPaths::ConvertRelativePathToFull(SourceFilePath);

		check(!SourceFilePath.IsEmpty());

		const FFuzzyPathMatcher::EPathMatch PathMatch = FuzzyPathMatcher.TestPath(SourceFilePath);
		if (PathMatch != FFuzzyPathMatcher::Included)
		{
			continue;
		}

		GatherTextFromUObject(*It, Arguments);
	}
}

bool FStructureEditorUtils::Change3dWidgetEnabled(UUserDefinedStruct* Struct, FGuid VarGuid, bool bIsEnabled)
{
	FStructVariableDescription* VarDesc = GetVarDescByGuid(Struct, VarGuid);
	if (!VarDesc)
	{
		return false;
	}

	const UStruct* PropertyStruct = Cast<const UStruct>(VarDesc->SubCategoryObject.Get());
	if (FEdMode::CanCreateWidgetForStructure(PropertyStruct) && (VarDesc->bEnable3dWidget != bIsEnabled))
	{
		const FScopedTransaction Transaction(LOCTEXT("Change3dWidgetEnabled", "Change 3d Widget Enabled"));
		ModifyStructData(Struct);

		VarDesc->bEnable3dWidget = bIsEnabled;
		UProperty* Property = FindField<UProperty>(Struct, VarDesc->VarName);
		if (Property)
		{
			if (VarDesc->bEnable3dWidget)
			{
				Property->SetMetaData(FEdMode::MD_MakeEditWidget, TEXT("true"));
			}
			else
			{
				Property->RemoveMetaData(FEdMode::MD_MakeEditWidget);
			}
		}
		return true;
	}
	return false;
}

static UProperty *get_field_from_name(UScriptStruct *u_struct, char *name)
{
	FString attr = UTF8_TO_TCHAR(name);
	UProperty *u_property = u_struct->FindPropertyByName(FName(*attr));
	if (u_property)
		return u_property;

#if WITH_EDITOR
	static const FName DisplayNameKey(TEXT("DisplayName"));

	// if the property is not found, attempt to search for DisplayName
	for (TFieldIterator<UProperty> prop(u_struct); prop; ++prop)
	{
		UProperty *property = *prop;
		if (property->HasMetaData(DisplayNameKey))
		{
			FString display_name = property->GetMetaData(DisplayNameKey);
			if (display_name.Len() > 0 && attr.Equals(display_name))
			{
				return property;
			}
		}
	}
#endif

	return nullptr;
}

void GetKeyablePropertyPaths(UClass* Class, UStruct* PropertySource, TArray<UProperty*>& PropertyPath, FSequencer& Sequencer, TArray<TArray<UProperty*>>& KeyablePropertyPaths)
{
	//@todo need to resolve this between UMG and the level editor sequencer
	const bool bRecurseAllProperties = Sequencer.IsLevelEditorSequencer();

	for (TFieldIterator<UProperty> PropertyIterator(PropertySource); PropertyIterator; ++PropertyIterator)
	{
		UProperty* Property = *PropertyIterator;

		if (Property && !Property->HasAnyPropertyFlags(CPF_Deprecated))
		{
			PropertyPath.Add(Property);

			bool bIsPropertyKeyable = Sequencer.CanKeyProperty(FCanKeyPropertyParams(Class, PropertyPath));
			if (bIsPropertyKeyable)
			{
				KeyablePropertyPaths.Add(PropertyPath);
			}

			if (!bIsPropertyKeyable || bRecurseAllProperties)
			{
				UStructProperty* StructProperty = Cast<UStructProperty>(Property);
				if (StructProperty != nullptr)
				{
					GetKeyablePropertyPaths(Class, StructProperty->Struct, PropertyPath, Sequencer, KeyablePropertyPaths);
				}
			}

			PropertyPath.RemoveAt(PropertyPath.Num() - 1);
		}
	}
}

void UNavAreaMeta_SwitchByAgent::UpdateAgentConfig()
{
	Super::UpdateAgentConfig();

	const UNavigationSystem* DefNavSys = (UNavigationSystem*)(UNavigationSystem::StaticClass()->GetDefaultObject());
	check(DefNavSys);

	const int32 MaxAllowedAgents = 16;
	const int32 NumAgents = FMath::Min(DefNavSys->GetSupportedAgents().Num(), MaxAllowedAgents);
	if (DefNavSys->GetSupportedAgents().Num() > MaxAllowedAgents)
	{
		UE_LOG(LogNavigation, Error, TEXT("Navigation system supports %d agents, but only %d can be shown in %s properties!"),
			DefNavSys->GetSupportedAgents().Num(), MaxAllowedAgents, *GetClass()->GetName());
	}

	const FString CustomNameMeta = TEXT("DisplayName");
	for (int32 i = 0; i < MaxAllowedAgents; i++)
	{
		const FString PropName = FString::Printf(TEXT("Agent%dArea"), i);
		UProperty* Prop = FindField<UProperty>(UNavAreaMeta_SwitchByAgent::StaticClass(), *PropName);
		check(Prop);

		if (i < NumAgents && NumAgents > 1)
		{
			Prop->SetPropertyFlags(CPF_Edit);
			Prop->SetMetaData(*CustomNameMeta, *FString::Printf(TEXT("Area Class for: %s"), *DefNavSys->GetSupportedAgents()[i].Name.ToString()));
		}
		else
		{
			Prop->ClearPropertyFlags(CPF_Edit);
		}
	}
}

	/**
	 * Scans for changes to the value
	 *
	 * @param bRecacheNewValues	If true, recaches new values found
	 * @return true if any changes were found
	 */
	bool ScanForChanges( bool bRecacheNewValues )
	{
		FPropertyNode& PropertyNodeRef = *PropertyNode.Pin();
		UProperty* Property = PropertyNodeRef.GetProperty();

		bool bPropertyValid = true;
		bool bChanged = false;

		UArrayProperty* OuterArrayProperty = Cast<UArrayProperty>( Property->GetOuter() );
		if ( OuterArrayProperty != NULL )
		{
			// make sure we're not trying to compare against an element that doesn't exist
			if ( PropertyNodeRef.GetArrayIndex() >= FScriptArrayHelper::Num( PropertyValueBaseAddress ) )
			{
				bPropertyValid = false;
			}
		}

		if( bPropertyValid )
		{
			bChanged = !Property->Identical( PropertyValueAddress, Data.GetData() );
			if( bRecacheNewValues )
			{
				CacheValue();
			}
		}

		return bChanged;
	}

void UDeveloperSettings::ImportConsoleVariableValues()
{
	for (UProperty* Property = GetClass()->PropertyLink; Property; Property = Property->PropertyLinkNext)
	{
		if (!Property->HasAnyPropertyFlags(CPF_Config))
		{
			continue;
		}

		FString CVarName = Property->GetMetaData(DeveloperSettingsConsoleVariableMetaFName);
		if (!CVarName.IsEmpty())
		{
			IConsoleVariable* CVar = IConsoleManager::Get().FindConsoleVariable(*CVarName);
			if (CVar)
			{
				if (Property->ImportText(*CVar->GetString(), Property->ContainerPtrToValuePtr<uint8>(this, 0), PPF_ConsoleVariable, this) == NULL)
				{
					UE_LOG(LogTemp, Error, TEXT("%s import failed for %s on console variable %s (=%s)"), *GetClass()->GetName(), *Property->GetName(), *CVarName, *CVar->GetString());
				}
			}
			else
			{
				UE_LOG(LogTemp, Fatal, TEXT("%s failed to find console variable %s for %s"), *GetClass()->GetName(), *CVarName, *Property->GetName());
			}
		}
	}
}

	void CollectBlackboardSelectors(const UObject* Ob, const UClass* StopAtClass, TArray<FName>& KeyNames)
	{
		for (UProperty* TestProperty = Ob->GetClass()->PropertyLink; TestProperty; TestProperty = TestProperty->PropertyLinkNext)
		{
			// stop when reaching base class
			if (TestProperty->GetOuter() == StopAtClass)
			{
				break;
			}

			// skip properties without any setup data	
			if (TestProperty->HasAnyPropertyFlags(CPF_Transient) ||
				TestProperty->HasAnyPropertyFlags(CPF_DisableEditOnInstance))
			{
				continue;
			}

			const UStructProperty* StructProp = Cast<const UStructProperty>(TestProperty);
			if (StructProp && StructProp->GetCPPType(NULL, CPPF_None).Contains(GET_STRUCT_NAME_CHECKED(FBlackboardKeySelector)))
			{
				const FBlackboardKeySelector* PropData = TestProperty->ContainerPtrToValuePtr<FBlackboardKeySelector>(Ob);
				KeyNames.AddUnique(PropData->SelectedKeyName);
			}
		}
	}

bool UK2Node::CreatePinsForFunctionEntryExit(const UFunction* Function, bool bForFunctionEntry)
{
	const UEdGraphSchema_K2* K2Schema = GetDefault<UEdGraphSchema_K2>();

	// Create the inputs and outputs
	bool bAllPinsGood = true;
	for (TFieldIterator<UProperty> PropIt(Function); PropIt && (PropIt->PropertyFlags & CPF_Parm); ++PropIt)
	{
		UProperty* Param = *PropIt;

		const bool bIsFunctionInput = !Param->HasAnyPropertyFlags(CPF_OutParm) || Param->HasAnyPropertyFlags(CPF_ReferenceParm);

		if (bIsFunctionInput == bForFunctionEntry)
		{
			const EEdGraphPinDirection Direction = bForFunctionEntry ? EGPD_Output : EGPD_Input;

			UEdGraphPin* Pin = CreatePin(Direction, TEXT(""), TEXT(""), NULL, false, false, Param->GetName());
			const bool bPinGood = K2Schema->ConvertPropertyToPinType(Param, /*out*/ Pin->PinType);
			K2Schema->SetPinDefaultValueBasedOnType(Pin);
			
			UK2Node_CallFunction::GeneratePinTooltipFromFunction(*Pin, Function);

			bAllPinsGood = bAllPinsGood && bPinGood;
		}
	}

	return bAllPinsGood;
}