llvm::FileOutputBuffer Class Reference

FileOutputBuffer - This interface provides simple way to create an in-memory buffer which will be written to a file. More...

#include "llvm/Support/FileOutputBuffer.h"

Public Types
enum	{ F_executable = 1 , F_no_mmap = 2 }

Public Member Functions
virtual uint8_t *	getBufferStart () const =0
	Returns a pointer to the start of the buffer.
virtual uint8_t *	getBufferEnd () const =0
	Returns a pointer to the end of the buffer.
virtual size_t	getBufferSize () const =0
	Returns size of the buffer.
StringRef	getPath () const
	Returns path where file will show up if buffer is committed.
virtual Error	commit ()=0
	Flushes the content of the buffer to its file and deallocates the buffer.
virtual	~FileOutputBuffer ()=default
	If this object was previously committed, the destructor just deletes this object.
virtual void	discard ()
	This removes the temporary file (unless it already was committed) but keeps the memory mapping alive.

Static Public Member Functions
static Expected< std::unique_ptr< FileOutputBuffer > >	create (StringRef FilePath, size_t Size, unsigned Flags=0)
	Factory method to create an OutputBuffer object which manages a read/write buffer of the specified size.

Protected Member Functions
	FileOutputBuffer (StringRef Path)

Protected Attributes
std::string	FinalPath

Detailed Description

FileOutputBuffer - This interface provides simple way to create an in-memory buffer which will be written to a file.

During the lifetime of these objects, the content or existence of the specified file is undefined. That is, creating an OutputBuffer for a file may immediately remove the file. If the FileOutputBuffer is committed, the target file's content will become the buffer content at the time of the commit. If the FileOutputBuffer is not committed, the file will be deleted in the FileOutputBuffer destructor.

Definition at line 28 of file FileOutputBuffer.h.

Member Enumeration Documentation

anonymous enum

anonymous enum

Enumerator
F_executable	Set the 'x' bit on the resulting file.
F_no_mmap	Don't use mmap and instead write an in-memory buffer to a file when this buffer is closed.

Definition at line 30 of file FileOutputBuffer.h.

Constructor & Destructor Documentation

~FileOutputBuffer()

virtual llvm::FileOutputBuffer::~FileOutputBuffer ( )

virtualdefault

If this object was previously committed, the destructor just deletes this object.

If this object was not committed, the destructor deallocates the buffer and the target file is never written.

FileOutputBuffer()

llvm::FileOutputBuffer::FileOutputBuffer ( StringRef  Path )

inlineprotected

Definition at line 80 of file FileOutputBuffer.h.

Member Function Documentation

commit()

virtual Error llvm::FileOutputBuffer::commit ( )

pure virtual

Flushes the content of the buffer to its file and deallocates the buffer.

If commit() is not called before this object's destructor is called, the file is deleted in the destructor. The optional parameter is used if it turns out you want the file size to be smaller than initially requested.

create()

Expected< std::unique_ptr< FileOutputBuffer > > FileOutputBuffer::create ( StringRef  FilePath, size_t  Size, unsigned  Flags = 0  )

static

Factory method to create an OutputBuffer object which manages a read/write buffer of the specified size.

When committed, the buffer will be written to the file at the specified path.

When F_modify is specified and FilePath refers to an existing on-disk file Size may be set to -1, in which case the entire file is used. Otherwise, the file shrinks or grows as necessary based on the value of Size. It is an error to specify F_modify and Size=-1 if FilePath does not exist.

Definition at line 159 of file FileOutputBuffer.cpp.

References llvm::sys::fs::all_exe, llvm::sys::fs::all_read, llvm::sys::fs::all_write, createInMemoryBuffer(), createOnDiskBuffer(), llvm::errorCodeToError(), F_executable, F_no_mmap, llvm::is_a_directory, Size, and llvm::sys::fs::status().

Referenced by llvm::msf::MSFBuilder::commit(), llvm::objcopy::deepWriteArchive(), llvm::objcopy::coff::dumpSection(), dumpSectionToFile(), llvm::objcopy::wasm::dumpSectionToFile(), and llvm::ifs::writeELFBinaryToFile().

discard()

virtual void llvm::FileOutputBuffer::discard ( )

inlinevirtual

This removes the temporary file (unless it already was committed) but keeps the memory mapping alive.

Definition at line 77 of file FileOutputBuffer.h.

getBufferEnd()

virtual uint8_t * llvm::FileOutputBuffer::getBufferEnd ( ) const

pure virtual

Returns a pointer to the end of the buffer.

getBufferSize()

virtual size_t llvm::FileOutputBuffer::getBufferSize ( ) const

pure virtual

Returns size of the buffer.

getBufferStart()

virtual uint8_t * llvm::FileOutputBuffer::getBufferStart ( ) const

pure virtual

Returns a pointer to the start of the buffer.

getPath()

StringRef llvm::FileOutputBuffer::getPath ( ) const

inline

Returns path where file will show up if buffer is committed.

Definition at line 61 of file FileOutputBuffer.h.

References FinalPath.

Member Data Documentation

FinalPath

std::string llvm::FileOutputBuffer::FinalPath

protected

Definition at line 82 of file FileOutputBuffer.h.

Referenced by getPath().

---

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

• include/llvm/Support/FileOutputBuffer.h
• lib/Support/FileOutputBuffer.cpp