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  3. FUniversalObjectLocatorFragment

FUniversalObjectLocatorFragment

Universal Object Locator (UOL) Fragments provide an extensible mechanism for referencing permanent, transient or dynamically created objects relative to an external context.

API > API/Runtime > API/Runtime/UniversalObjectLocator

Inheritance Hierarchy

References

   
Module UniversalObjectLocator
Header /Engine/Source/Runtime/UniversalObjectLocator/Public/UniversalObjectLocatorFragment.h
Include #include "UniversalObjectLocatorFragment.h"

Syntax

USTRUCT (BlueprintType )  
struct FUniversalObjectLocatorFragment

Remarks

Universal Object Locator (UOL) Fragments provide an extensible mechanism for referencing permanent, transient or dynamically created objects relative to an external context. UOLs comprise zero or more nested fragments.

Creation and resolution of a fragment requires a context to be provided; normally this will be the object on which the UOL exists as a property.

The way in which the object is referenced is defined by globally registered 'FragmentTypes' (See IUniversalObjectLocatorModule::RegisterFragmentType). Each FragmentType can be thought of as somewhat equivalent to a www URI fragment type, though the 'path' is not necessarily just a string, but includes support for the full set of Engine Property types.

The type is implemented as a type-erased payload block, a fragment type handle and some internal flags. Payloads will be allocated using the inline memory if alignment and size constraints allow, but will fall back to a heap allocation if necessary. Allocation should be avoided by keeping payload types small.

Aligned to 8 bytes, 32 (runtime) or 64 (editor) bytes big.

Constructors

  Type Name Description
Public function   Default constructor: initializes to an empty fragment with no fragment type
Public function  

FUniversalObjectLocatorFragment ( const UE::UniversalObjectLocator::FFragmentType& InFragmentType
)

 Construct a new fragment with a specific fragment type and default-constructed payload.
Public function   Copy construction/assignment
Public function   Move construction/assignment
Public function   Construct a new fragment with a specific fragment type and data.
Public function  

FUniversalObjectLocatorFragment ( const UObject* InObject,
UObject* Context
)

 Construct this fragment by binding it to an object within a given context.

Destructors

  Type Name Description
Public function   Destructor - destructs the payload, and frees any heap allocation as necessary

Functions

  Type Name Description
Public function void  
Protected function Const void

CheckPayloadType ( UScriptStruct* TypeToCompare
)

 Runtime type-checking against specific struct types.
Protected function void Destroy the payload (if valid) by calling its destructor and freeing the memory (if necessary)
Public function Const bool

ExportTextItem ( FString& ValueStr,
const FUniversalObjectLocatorFragment& DefaultValue,
UObject* Parent,
int32 PortFlags,
UObject* ExportRootScope
)

  
Public function Const UScriptStruct * Retrieve this fragment's fragment struct type
Public function Const const UE::UniversalObjectLocator::FFragmentType * Retrieve this fragment's fragment type
Public function Const UE::UniversalObjectLocator::FFragmentTypeHandle Retrieve this fragment's fragment type handle
Public function Const const void * Retrieve this fragment's payload data
Public function void * Retrieve this fragment's payload data
Public function Const const T * Try and retrieve this fragment's payload as a specific type using its fragment type handle
Public function T * Try and retrieve this fragment's payload as a specific type using its fragment type handle
Public function void  
Public function bool

ImportTextItem ( const TCHAR*& Buffer,
int32 PortFlags,
UObject* Parent,
FOutputDevice* ErrorText,
FArchive* InSerializingArchive
)

  
Protected function void

InitializePayload ( const UScriptStruct* StructType
)

 Default-initialize the fragment payload using the specified type
Public function Const bool

IsEmpty ()

 Check whether this reference is empty.
Public function void

Reset ( const UObject* InObject,
UObject* Context
)

 Reset this fragment to point to a new object from the specified context
Public function void

Reset ( const UObject* InObject,
UObject* Context,
TFunctionRef< bool(UE::UniversalObjectLocator::FFragmentTypeHandle)> CanUseFragmentType
)

 Reset this fragment to point to a new object from the specified context using a filtered set of fragment types
Public function void

Reset ()

 Reset this fragment back to its default-constructed, empty state
Public function Const UE::UniversalObjectLocator::FResolveResult

Resolve ( const UE::UniversalObjectLocator::FResolveParams& Params
)

 Attempt to resolve this fragment by invoking the payload's 'Resolve' function
Public function bool  
Public function bool  
Public function Const void

ToString ( FStringBuilderBase& OutString
)

 Convert this fragment to a string of the form fragment-id[=fragment-payload]
Public function Const bool Try and retrieve this fragment's payload as a specific type using its fragment type handle
Public function bool Try and retrieve this fragment's payload as a specific type using its fragment type handle
Public function FParseStringResult Attempt to deserialize this fragment's payload from a string, based on its currently assigned type The state of this instance will not be changed if this function returns false.
Public function FParseStringResult

TryParseFragmentType ( FStringView InString,
const FParseStringParams& InParams
)

 Attempt to default initialize this fragment using a string that defines the type The state of this instance will not be changed if this function returns false.
Public function FParseStringResult

TryParseString ( FStringView InString,
const FParseStringParams& InParams
)

 Attempt to initialize this fragment from a string of the form fragment-type-id[=payload] The state of this instance will not be changed if this function returns false.

Operators

  Type Name Description
Public function FUniversalObjectLocatorFragment &  
Public function FUniversalObjectLocatorFragment &  

Typedefs

Name Description
FParseStringParams  
FParseStringResult  

Constants

Name Description
Size Make our inline data buffer larger in-editor to support editor-only data without allocation
ValidFragmentDelimiters Valid fragment delimiters are those that are allowable by RFC3986 for the query part (unreserved / pct-encoded / sub-delims / ":" / "@" / "/" / "?") excluding '&' which we use to separate fragments within a path.
ValidFragmentPayloadCharacters  
ValidFragmentTypeCharacters  

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