A file system that allows overlaying one AbstractFileSystem on top of another. More...

#include "llvm/Support/VirtualFileSystem.h"

Inheritance diagram for llvm::vfs::OverlayFileSystem:

[legend]

Public Types
using	iterator = FileSystemList::reverse_iterator

using	const_iterator = FileSystemList::const_reverse_iterator

using	reverse_iterator = FileSystemList::iterator

using	const_reverse_iterator = FileSystemList::const_iterator

using	range = iterator_range< iterator >

using	const_range = iterator_range< const_iterator >

Public Types inherited from llvm::vfs::FileSystem
enum class	PrintType { Summary , Contents , RecursiveContents }

Public Member Functions
	OverlayFileSystem (IntrusiveRefCntPtr< FileSystem > Base)

void	pushOverlay (IntrusiveRefCntPtr< FileSystem > FS)
	Pushes a file system on top of the stack.

llvm::ErrorOr< Status >	status (const Twine &Path) override
	Get the status of the entry at `Path`, if one exists.

llvm::ErrorOr< std::unique_ptr< File > >	openFileForRead (const Twine &Path) override
	Get a `File` object for the file at `Path`, if one exists.

directory_iterator	dir_begin (const Twine &Dir, std::error_code &EC) override
	Get a directory_iterator for `Dir`.

llvm::ErrorOr< std::string >	getCurrentWorkingDirectory () const override
	Get the working directory of this file system.

std::error_code	setCurrentWorkingDirectory (const Twine &Path) override
	Set the working directory.

std::error_code	isLocal (const Twine &Path, bool &Result) override
	Is the file mounted on a local filesystem?

std::error_code	getRealPath (const Twine &Path, SmallVectorImpl< char > &Output) const override
	Gets real path of `Path` e.g.

iterator	overlays_begin ()
	Get an iterator pointing to the most recently added file system.

const_iterator	overlays_begin () const

iterator	overlays_end ()
	Get an iterator pointing one-past the least recently added file system.

const_iterator	overlays_end () const

reverse_iterator	overlays_rbegin ()
	Get an iterator pointing to the least recently added file system.

const_reverse_iterator	overlays_rbegin () const

reverse_iterator	overlays_rend ()
	Get an iterator pointing one-past the most recently added file system.

const_reverse_iterator	overlays_rend () const

range	overlays_range ()

const_range	overlays_range () const

Public Member Functions inherited from llvm::vfs::FileSystem
virtual	~FileSystem ()

virtual llvm::ErrorOr< Status >	status (const Twine &Path)=0
	Get the status of the entry at `Path`, if one exists.

virtual llvm::ErrorOr< std::unique_ptr< File > >	openFileForRead (const Twine &Path)=0
	Get a `File` object for the file at `Path`, if one exists.

llvm::ErrorOr< std::unique_ptr< llvm::MemoryBuffer > >	getBufferForFile (const Twine &Name, int64_t FileSize=-1, bool RequiresNullTerminator=true, bool IsVolatile=false)
	This is a convenience method that opens a file, gets its content and then closes the file.

virtual directory_iterator	dir_begin (const Twine &Dir, std::error_code &EC)=0
	Get a directory_iterator for `Dir`.

virtual std::error_code	setCurrentWorkingDirectory (const Twine &Path)=0
	Set the working directory.

virtual llvm::ErrorOr< std::string >	getCurrentWorkingDirectory () const =0
	Get the working directory of this file system.

virtual std::error_code	getRealPath (const Twine &Path, SmallVectorImpl< char > &Output) const
	Gets real path of `Path` e.g.

bool	exists (const Twine &Path)
	Check whether a file exists. Provided for convenience.

virtual std::error_code	isLocal (const Twine &Path, bool &Result)
	Is the file mounted on a local filesystem?

virtual std::error_code	makeAbsolute (SmallVectorImpl< char > &Path) const
	Make Path an absolute path.

void	print (raw_ostream &OS, PrintType Type=PrintType::Contents, unsigned IndentLevel=0) const

LLVM_DUMP_METHOD void	dump () const

Public Member Functions inherited from llvm::ThreadSafeRefCountedBase< FileSystem >
unsigned	UseCount () const

void	Retain () const

void	Release () const

Protected Member Functions
void	printImpl (raw_ostream &OS, PrintType Type, unsigned IndentLevel) const override

Protected Member Functions inherited from llvm::vfs::FileSystem
virtual void	printImpl (raw_ostream &OS, PrintType Type, unsigned IndentLevel) const

void	printIndent (raw_ostream &OS, unsigned IndentLevel) const

Protected Member Functions inherited from llvm::ThreadSafeRefCountedBase< FileSystem >
	ThreadSafeRefCountedBase ()=default

	ThreadSafeRefCountedBase (const ThreadSafeRefCountedBase &)

ThreadSafeRefCountedBase &	operator= (const ThreadSafeRefCountedBase &)=delete

	~ThreadSafeRefCountedBase ()

Detailed Description

A file system that allows overlaying one AbstractFileSystem on top of another.

Consists of a stack of >=1 FileSystem objects, which are treated as being one merged file system. When there is a directory that exists in more than one file system, the OverlayFileSystem contains a directory containing the union of their contents. The attributes (permissions, etc.) of the top-most (most recently added) directory are used. When there is a file that exists in more than one file system, the file in the top-most file system overrides the other(s).

Definition at line 366 of file VirtualFileSystem.h.

Member Typedef Documentation

◆ const_iterator

using llvm::vfs::OverlayFileSystem::const_iterator = FileSystemList::const_reverse_iterator

Definition at line 390 of file VirtualFileSystem.h.

◆ const_range

using llvm::vfs::OverlayFileSystem::const_range = iterator_range<const_iterator>

Definition at line 394 of file VirtualFileSystem.h.

◆ const_reverse_iterator

using llvm::vfs::OverlayFileSystem::const_reverse_iterator = FileSystemList::const_iterator

Definition at line 392 of file VirtualFileSystem.h.

◆ iterator

using llvm::vfs::OverlayFileSystem::iterator = FileSystemList::reverse_iterator

Definition at line 389 of file VirtualFileSystem.h.

◆ range

using llvm::vfs::OverlayFileSystem::range = iterator_range<iterator>

Definition at line 393 of file VirtualFileSystem.h.

◆ reverse_iterator

using llvm::vfs::OverlayFileSystem::reverse_iterator = FileSystemList::iterator

Definition at line 391 of file VirtualFileSystem.h.

Constructor & Destructor Documentation

◆ OverlayFileSystem()

OverlayFileSystem::OverlayFileSystem ( IntrusiveRefCntPtr< FileSystem > Base )

Definition at line 421 of file VirtualFileSystem.cpp.

References llvm::SmallVectorTemplateBase< T, bool >::push_back().

Member Function Documentation

◆ dir_begin()

directory_iterator OverlayFileSystem::dir_begin	(	const Twine &	Dir,
		std::error_code &	EC
	)

overridevirtual

Get a directory_iterator for Dir.

Note: The 'end' iterator is directory_iterator().

Implements llvm::vfs::FileSystem.

Definition at line 579 of file VirtualFileSystem.cpp.

References llvm::Twine::str().

◆ getCurrentWorkingDirectory()

llvm::ErrorOr< std::string > OverlayFileSystem::getCurrentWorkingDirectory ( ) const

overridevirtual

Get the working directory of this file system.

Implements llvm::vfs::FileSystem.

Definition at line 454 of file VirtualFileSystem.cpp.

References llvm::SmallVectorTemplateCommon< T, typename >::front().

Referenced by pushOverlay().

◆ getRealPath()

std::error_code OverlayFileSystem::getRealPath	(	const Twine &	Path,
		SmallVectorImpl< char > &	Output
	)		const

overridevirtual

Gets real path of Path e.g.

collapse all . and .. patterns, resolve symlinks. For real file system, this uses llvm::sys::fs::real_path. This returns errc::operation_not_permitted if not implemented by subclass.

Reimplemented from llvm::vfs::FileSystem.

Definition at line 475 of file VirtualFileSystem.cpp.

References llvm::no_such_file_or_directory.