IFileHandle Class Reference

#include <GenericPlatformFile.h>

Inheritance diagram for IFileHandle:

Public Member Functions
virtual	~IFileHandle ()
virtual int64	Tell ()=0
virtual bool	Seek (int64 NewPosition)=0
virtual bool	SeekFromEnd (int64 NewPositionRelativeToEnd=0)=0
virtual bool	Read (uint8 *Destination, int64 BytesToRead)=0
virtual bool	ReadAt (uint8 *Destination, int64 BytesToRead, int64 Offset)=0
virtual bool	Write (const uint8 *Source, int64 BytesToWrite)=0
virtual bool	Flush (const bool bFullFlush=false)=0
virtual bool	Truncate (int64 NewSize)=0
virtual void	ShrinkBuffers ()
virtual CORE_API int64	Size ()

Detailed Description

File handle interface.

Constructor & Destructor Documentation

~IFileHandle()

virtual IFileHandle::~IFileHandle ( )

inlinevirtual

Destructor, also the only way to close the file handle

Member Function Documentation

Flush()

virtual bool IFileHandle::Flush ( const bool  bFullFlush = false )

pure virtual

Flushes file handle to disk.

Parameters

bFullFlush

true to flush everything about the file (including its meta-data) with a strong guarantee that it will be on disk by the time this function returns, or false to let the operating/file system have more leeway about when the data actually gets written to disk

Returns

true if operation completed successfully.

Implemented in FFileHandleApple, FIOSFileHandle, FFileHandleUnix, FFileHandleWindows, FCachedFileHandle, FLoggedFileHandle, FManagedStorageFileWriteHandle, FNetworkFileHandle, FPakFileHandle< ReaderPolicy >, FStorageServerFileHandle, and FStreamingNetworkFileHandle.

Read()

virtual bool IFileHandle::Read ( uint8 *  Destination, int64  BytesToRead  )

pure virtual

Read bytes from the file.

Parameters

Destination	Buffer to holds the results, should be at least BytesToRead in size.
BytesToRead	Number of bytes to read into the destination.

Returns

true if the operation completed successfully. Returns false if a read is attempted while the read position is already at the end of the file.

Remarks

If BytesToRead is larger than the bytes remaining in the file from the current read position the Read() will return true if the underlying file read could read all remaining bytes.

Implemented in FFileHandleApple, FIOSFileHandle, FFileHandleUnix, FFileHandleWindows, FCachedFileHandle, FLoggedFileHandle, FManagedStorageFileWriteHandle, FNetworkFileHandle, FPakFileHandle< ReaderPolicy >, FStorageServerFileHandle, and FStreamingNetworkFileHandle.

ReadAt()

virtual bool IFileHandle::ReadAt ( uint8 *  Destination, int64  BytesToRead, int64  Offset  )

pure virtual

Implemented in FStorageServerFileHandle, FFileHandleApple, FIOSFileHandle, FFileHandleUnix, FFileHandleWindows, FCachedFileHandle, FLoggedFileHandle, FManagedStorageFileWriteHandle, FPakFileHandle< ReaderPolicy >, and FStreamingNetworkFileHandle.

Seek()

virtual bool IFileHandle::Seek ( int64  NewPosition )

pure virtual

Change the current write or read position.

Parameters

NewPosition

new write or read position

Returns

true if the operation completed successfully.

Implemented in FFileHandleApple, FIOSFileHandle, FFileHandleUnix, FFileHandleWindows, FCachedFileHandle, FLoggedFileHandle, FManagedStorageFileWriteHandle, FNetworkFileHandle, FPakFileHandle< ReaderPolicy >, FStorageServerFileHandle, and FStreamingNetworkFileHandle.

SeekFromEnd()

virtual bool IFileHandle::SeekFromEnd ( int64  NewPositionRelativeToEnd = 0 )

pure virtual

Change the current write or read position, relative to the end of the file.

Parameters

NewPositionRelativeToEnd

new write or read position, relative to the end of the file should be <=0!

Returns

true if the operation completed successfully.

Implemented in FLoggedFileHandle, FPakFileHandle< ReaderPolicy >, FFileHandleApple, FIOSFileHandle, FFileHandleUnix, FFileHandleWindows, FCachedFileHandle, FManagedStorageFileWriteHandle, FNetworkFileHandle, FStorageServerFileHandle, and FStreamingNetworkFileHandle.

ShrinkBuffers()

virtual void IFileHandle::ShrinkBuffers ( )

inlinevirtual

Minimizes optional system or process cache kept for the file.

Reimplemented in FFileHandleWindows, FCachedFileHandle, FLoggedFileHandle, and FManagedStorageFileWriteHandle.

Size()

int64 IFileHandle::Size ( )

virtual

Return the total size of the file

Reimplemented in FFileHandleApple, FIOSFileHandle, FFileHandleUnix, FFileHandleWindows, FCachedFileHandle, FLoggedFileHandle, FManagedStorageFileWriteHandle, FPakFileHandle< ReaderPolicy >, FStorageServerFileHandle, and FStreamingNetworkFileHandle.

Tell()

virtual int64 IFileHandle::Tell ( )

pure virtual

Return the current write or read position.

Implemented in FFileHandleApple, FIOSFileHandle, FFileHandleUnix, FCachedFileHandle, FLoggedFileHandle, FManagedStorageFileWriteHandle, FNetworkFileHandle, FPakFileHandle< ReaderPolicy >, FStorageServerFileHandle, FStreamingNetworkFileHandle, and FFileHandleWindows.

Truncate()

virtual bool IFileHandle::Truncate ( int64  NewSize )

pure virtual

Truncate the file to the given size (in bytes).

Parameters

NewSize

Truncated file size (in bytes).

Returns

true if the operation completed successfully.

Implemented in FFileHandleApple, FIOSFileHandle, FFileHandleUnix, FFileHandleWindows, FCachedFileHandle, FLoggedFileHandle, FManagedStorageFileWriteHandle, FNetworkFileHandle, FPakFileHandle< ReaderPolicy >, FStorageServerFileHandle, and FStreamingNetworkFileHandle.

Write()

virtual bool IFileHandle::Write ( const uint8 *  Source, int64  BytesToWrite  )

pure virtual

Write bytes to the file.

Parameters

Source	Buffer to write, should be at least BytesToWrite in size.
BytesToWrite	Number of bytes to write.

Returns

true if the operation completed successfully.

Implemented in FFileHandleApple, FIOSFileHandle, FFileHandleUnix, FFileHandleWindows, FCachedFileHandle, FLoggedFileHandle, FManagedStorageFileWriteHandle, FNetworkFileHandle, FPakFileHandle< ReaderPolicy >, FStorageServerFileHandle, and FStreamingNetworkFileHandle.

---

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

• Engine/Source/Runtime/Core/Public/GenericPlatform/GenericPlatformFile.h
• Engine/Source/Runtime/Core/Private/GenericPlatform/GenericPlatformFile.cpp