IFileCacheHandle Class Reference

#include <FileCache.h>

Inheritance diagram for IFileCacheHandle:

Public Member Functions
virtual	~IFileCacheHandle ()
virtual IMemoryReadStreamRef	ReadData (FGraphEventArray &OutCompletionEvents, int64 Offset, int64 BytesToRead, EAsyncIOPriorityAndFlags Priority)=0
virtual FGraphEventRef	PreloadData (const FFileCachePreloadEntry *PreloadEntries, int32 NumEntries, EAsyncIOPriorityAndFlags Priority)=0
virtual void	WaitAll ()=0

Static Public Member Functions
static CORE_API void	EvictAll ()
static CORE_API IFileCacheHandle *	CreateFileCacheHandle (const TCHAR *InFileName, int64 InBaseOffset=0)
static CORE_API IFileCacheHandle *	CreateFileCacheHandle (IAsyncReadFileHandle *FileHandle, int64 InBaseOffset=0)
static CORE_API int64	GetFileCacheSize ()

Detailed Description

All methods may be safely called from multiple threads simultaneously, unless otherwise noted

Also note, if you create several IFileCacheHandle's to the same file on separate threads these will be considered as individual separate files from the cache point of view and thus each will have their own cache data allocated.

Constructor & Destructor Documentation

~IFileCacheHandle()

virtual IFileCacheHandle::~IFileCacheHandle ( )

inlinevirtual

Member Function Documentation

CreateFileCacheHandle() [1/2]

IFileCacheHandle * IFileCacheHandle::CreateFileCacheHandle ( const TCHAR *  InFileName, int64  InBaseOffset = 0  )

static

Create a IFileCacheHandle from a filename.

Parameters

InFileName

A path to a file.

Returns

A IFileCacheHandle that can be used to make read requests. This will be a nullptr if the target file can not be accessed for any given reason.

CreateFileCacheHandle() [2/2]

IFileCacheHandle * IFileCacheHandle::CreateFileCacheHandle ( IAsyncReadFileHandle *  FileHandle, int64  InBaseOffset = 0  )

static

Create a IFileCacheHandle from a IAsyncReadFileHandle.

Parameters

FileHandle

A valid IAsyncReadFileHandle that has already been created elsewhere.

Returns

A IFileCacheHandle that can be used to make read requests. This will be a nullptr if the FileHandle was not valid.

EvictAll()

void IFileCacheHandle::EvictAll ( )

static

GetFileCacheSize()

int64 IFileCacheHandle::GetFileCacheSize ( )

static

Return size of underlying file cache in bytes.

PreloadData()

virtual FGraphEventRef IFileCacheHandle::PreloadData ( const FFileCachePreloadEntry *  PreloadEntries, int32  NumEntries, EAsyncIOPriorityAndFlags  Priority  )

pure virtual

Implemented in FFileCacheHandle.

ReadData()

virtual IMemoryReadStreamRef IFileCacheHandle::ReadData ( FGraphEventArray &  OutCompletionEvents, int64  Offset, int64  BytesToRead, EAsyncIOPriorityAndFlags  Priority  )

pure virtual

Read a byte range form the file. This can be a high-throughput operation and done lots of times for small reads. The system will handle this efficiently.

Parameters

OutCompletionEvents

Must wait until these events are complete before returned data is valid

Returns

Memory stream that contains the requested range. May return nullptr in rare cases if the request could not be serviced Data read from this stream will not be valid until all events returned in OutCompletionEvents are complete

Implemented in FFileCacheHandle.

WaitAll()

virtual void IFileCacheHandle::WaitAll ( )

pure virtual

Wait until all outstanding read requests complete.

Implemented in FFileCacheHandle.

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The documentation for this class was generated from the following files:

• Engine/Source/Runtime/Core/Public/FileCache/FileCache.h
• Engine/Source/Runtime/Core/Private/FileCache/FileCache.cpp