1. Epic GamesDeveloper
  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

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.

   
Name FUniversalObjectLocatorFragment
Type struct
Header File /Engine/Source/Runtime/UniversalObjectLocator/Public/UniversalObjectLocatorFragment.h
Include Path #include "UniversalObjectLocatorFragment.h"

Syntax

USTRUCT (BlueprintType )  
struct FUniversalObjectLocatorFragment

Derived Classes

Constructors

Name Remarks Include Path Unreal Specifiers
Default constructor: initializes to an empty fragment with no fragment type UniversalObjectLocatorFragment.h  
Move construction/assignment UniversalObjectLocatorFragment.h  
Construct a new fragment with a specific fragment type and data. UniversalObjectLocatorFragment.h  

FUniversalObjectLocatorFragment ( const UObject* InObject,
UObject* Context
)

 Construct this fragment by binding it to an object within a given context. UniversalObjectLocatorFragment.h  
Copy construction/assignment UniversalObjectLocatorFragment.h  
Construct a new fragment with a specific fragment type and default-constructed payload. UniversalObjectLocatorFragment.h  

Destructors

Name Remarks Include Path Unreal Specifiers

~FUniversalObjectLocatorFragment()

 Destructor - destructs the payload, and frees any heap allocation as necessary UniversalObjectLocatorFragment.h  

Structs

Name Remarks
FAllocatedPayload Describes a UOL fragment payload after it has been allocated Where UE_UNIVERSALOBJECTLOCATOR_DEBUG is enabled, the allocation will be laid out as such: 0..
FDebuggableFragment  
FDebuggableFragmentType  

Typedefs

Name Type Remarks Include Path
FParseStringParams UE::UniversalObjectLocator::FParseStringParams   UniversalObjectLocatorFragment.h
FParseStringResult UE::UniversalObjectLocator::FParseStringResult   UniversalObjectLocatorFragment.h

Constants

Name Type Remarks Include Path
SizeInMemory SIZE_T Make our inline data buffer larger in-editor to support editor-only data without allocation UniversalObjectLocatorFragment.h
ValidFragmentDelimiters FAsciiSet 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. UniversalObjectLocatorFragment.h
ValidFragmentPayloadCharacters FAsciiSet   UniversalObjectLocatorFragment.h
ValidFragmentTypeCharacters FAsciiSet   UniversalObjectLocatorFragment.h

Variables

Protected

Name Type Remarks Include Path Unreal Specifiers
bIsInitialized uint8 True when FragmentType has been assigned to a valid handle, and Data has been initialized with FragmentType::PayloadType UniversalObjectLocatorFragment.h  
bIsInline uint8 True if Data is an inline allocation of FragmentType::PayloadType, false means Data is a (void*) to the heap allocated data. UniversalObjectLocatorFragment.h  
Data uint8 Payload data - implicitly aligned to a 8 byte boundary since it's the first member. UniversalObjectLocatorFragment.h  
DebugHeaderSizeLog2 uint8 Offset from the allocated memory to the fragment payload stored as a power of 2. UniversalObjectLocatorFragment.h  
FragmentType UE::UniversalObjectLocator::FFragmentTypeHandle 1 Byte - the fragment type portion of the universal fragment UniversalObjectLocatorFragment.h  

Functions

Public

Name Remarks Include Path Unreal Specifiers

void AddStructReferencedObjects ( FReferenceCollector& Collector
)

   UniversalObjectLocatorFragment.h  

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

   UniversalObjectLocatorFragment.h  

UScriptStruct * GetFragmentStruct()

 Retrieve this fragment's fragment struct type UniversalObjectLocatorFragment.h  

const UE::UniversalObjectLocator::FFragmentType * GetFragmentType()

 Retrieve this fragment's fragment type UniversalObjectLocatorFragment.h  
Retrieve this fragment's fragment type handle UniversalObjectLocatorFragment.h  

const void * GetPayload ()

 Retrieve this fragment's payload data UniversalObjectLocatorFragment.h  

void * GetPayload ()

 Retrieve this fragment's payload data UniversalObjectLocatorFragment.h  
Try and retrieve this fragment's payload as a specific type using its fragment type handle UniversalObjectLocatorFragment.h  
Try and retrieve this fragment's payload as a specific type using its fragment type handle UniversalObjectLocatorFragment.h  

void GetPreloadDependencies ( TArray< UObject* >& OutDeps
)

   UniversalObjectLocatorFragment.h  

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

   UniversalObjectLocatorFragment.h  

bool IsEmpty ()

 Check whether this reference is empty. UniversalObjectLocatorFragment.h  

void Reset ( const UObject* InObject,
UObject* Context
)

 Reset this fragment to point to a new object from the specified context UniversalObjectLocatorFragment.h  

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 UniversalObjectLocatorFragment.h  

void Reset ()

 Reset this fragment back to its default-constructed, empty state UniversalObjectLocatorFragment.h  
Attempt to resolve this fragment by invoking the payload's 'Resolve' function UniversalObjectLocatorFragment.h  

bool Serialize ( FArchive& Ar
)

   UniversalObjectLocatorFragment.h  

bool SerializeFromMismatchedTag ( const FPropertyTag& Tag,
FStructuredArchive::FSlot Slot
)

   UniversalObjectLocatorFragment.h  

void ToString ( FStringBuilderBase& OutString
) const

 Convert this fragment to a string of the form fragment-id[=fragment-payload] UniversalObjectLocatorFragment.h  

bool TryGetPayloadAs ( UE::UniversalObjectLocator::TFragmentTypeHandle< T > InType,
const T*& OutData
) const

 Try and retrieve this fragment's payload as a specific type using its fragment type handle UniversalObjectLocatorFragment.h  
Try and retrieve this fragment's payload as a specific type using its fragment type handle UniversalObjectLocatorFragment.h  

FParseStringResult TryParseFragmentPayload ( FStringView InString,
const FParseStringParams& InParams
)

 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. UniversalObjectLocatorFragment.h  

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. UniversalObjectLocatorFragment.h  

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. UniversalObjectLocatorFragment.h  

Protected

Name Remarks Include Path Unreal Specifiers

FAllocatedPayload AllocatePayload ( size_t Size,
size_t Alignment
)

 Allocate (but do not initialize) the fragment payload using the specified size and alignment, accounting for enough space to fit a debug vftable ptr whern UE_UNIVERSALOBJECTLOCATOR_DEBUG is enabled. UniversalObjectLocatorFragment.h  

void CheckPayloadType ( UScriptStruct* TypeToCompare
) const

 Runtime type-checking against specific struct types. UniversalObjectLocatorFragment.h  

void DefaultConstructPayload ( const UE::UniversalObjectLocator::FFragmentType& InFragmentType
)

 Default-initialize the fragment payload using the specified type UniversalObjectLocatorFragment.h  

void DestroyPayload()

 Destroy the payload (if valid) by calling its destructor and freeing the memory (if necessary) UniversalObjectLocatorFragment.h  

Operators

Name Remarks Include Path Unreal Specifiers
  UniversalObjectLocatorFragment.h  
  UniversalObjectLocatorFragment.h  

Ask questions and help your peers Developer Forums

Write your own tutorials or read those from others Learning Library

On this page