#include <LowercaseFileSystem.h>

Inheritance diagram for LowercaseFileSystem:

Public Member Functions
	LowercaseFileSystem (FileSystem *base)

virtual	~LowercaseFileSystem ()

void	refresh ()

Public Member Functions inherited from FileSystem
	FileSystem ()=default

virtual	~FileSystem ()=default

bool	exists (std::string_view path) const

bool	exists (FileSystemPathView path) const

FileStat	stat (std::string_view path) const

FileStat	stat (FileSystemPathView path) const

std::vector< DirectoryEntry >	ls (std::string_view path) const

std::vector< DirectoryEntry >	ls (FileSystemPathView path) const

void	ls (std::string_view path, std::vector< DirectoryEntry > *entries) const

void	ls (FileSystemPathView path, std::vector< DirectoryEntry > *entries) const

Blob	read (std::string_view path) const

Blob	read (FileSystemPathView path) const

void	write (std::string_view path, const Blob &data)

void	write (FileSystemPathView path, const Blob &data)

std::unique_ptr< InputStream >	openForReading (std::string_view path) const

std::unique_ptr< InputStream >	openForReading (FileSystemPathView path) const

std::unique_ptr< OutputStream >	openForWriting (std::string_view path)

std::unique_ptr< OutputStream >	openForWriting (FileSystemPathView path)

void	rename (std::string_view srcPath, std::string_view dstPath)

void	rename (FileSystemPathView srcPath, FileSystemPathView dstPath)

bool	remove (std::string_view path)

bool	remove (FileSystemPathView path)

std::string	displayPath (std::string_view path) const

std::string	displayPath (FileSystemPathView path) const

Private Types
using	Node = FileSystemTrieNode< detail::LowercaseFileData >

Private Member Functions
virtual bool	_exists (FileSystemPathView path) const override

virtual FileStat	_stat (FileSystemPathView path) const override

virtual void	_ls (FileSystemPathView path, std::vector< DirectoryEntry > *entries) const override

virtual Blob	_read (FileSystemPathView path) const override

virtual void	_write (FileSystemPathView path, const Blob &data) override

virtual std::unique_ptr< InputStream >	_openForReading (FileSystemPathView path) const override

virtual std::unique_ptr< OutputStream >	_openForWriting (FileSystemPathView path) override

virtual void	_rename (FileSystemPathView srcPath, FileSystemPathView dstPath) override

virtual bool	_remove (FileSystemPathView path) override

virtual std::string	_displayPath (FileSystemPathView path) const override

std::tuple< FileSystemPath, Node *, FileSystemPathView >	walk (FileSystemPathView path) const

void	cacheLs (Node *node, FileSystemPathView basePath) const

void	invalidateLs (Node *node) const

void	cacheRemove (Node *node) const

void	cacheInsert (Node *node, FileSystemPathView tail, FileType type) const

FileSystemPath	locateForReading (FileSystemPathView path) const

std::tuple< FileSystemPath, Node *, FileSystemPathView >	locateForWriting (FileSystemPathView path)

Private Attributes
FileSystem *	_base = nullptr

FileSystemTrie< detail::LowercaseFileData >	_trie

Additional Inherited Members
Protected Types inherited from FileSystem
template<class T >
using	FileSystemTrieNode = detail::FileSystemTrieNode< T >

template<class T >
using	FileSystemTrie = detail::FileSystemTrie< T >

virtual bool	_exists (FileSystemPathView path) const =0

virtual FileStat	_stat (FileSystemPathView path) const =0

virtual void	_ls (FileSystemPathView path, std::vector< DirectoryEntry > *entries) const =0

virtual Blob	_read (FileSystemPathView path) const =0

virtual void	_write (FileSystemPathView path, const Blob &data)=0

virtual std::unique_ptr< InputStream >	_openForReading (FileSystemPathView path) const =0

virtual std::unique_ptr< OutputStream >	_openForWriting (FileSystemPathView path)=0

virtual void	_rename (FileSystemPathView srcPath, FileSystemPathView dstPath)

virtual bool	_remove (FileSystemPathView path)=0

virtual std::string	_displayPath (FileSystemPathView path) const =0

Detailed Description

Provides a lowercase view over another FileSystem:

Contains only lowercase-named files.
Effectively gives the user a case-insensitive view over a potentially case-sensitive filesystem.
Caches the contents of the underlying filesystem. Call refresh to clear cache.
Preserves empty folders that exist on the underlying FS, but also supports file systems that automatically prune empty folders.
Conflicts are visible as empty files but are not readable / writeable / removeable (conflict is when both "file.txt" and "FILE.txt" exist).
Is not thread-safe. Even const methods update the underlying cache.

Some notes on why it is designed the way it is designed.

Previous iteration was a writeable FS that was always up to date with the underlying FS (was checking timestamps for all parents in each call). The code was messy, it was O(N) on each call, and even after writing an implementation that actually worked, I hated it. Mostly because of the O(N) - which led to a recursive implementation of FileSystem::rename becoming O(N^2). It is possible to iron this out, but that would require to redo the FileSystem interface & expose the Directory abstraction directly. Which is just not worth it.

Next iteration was caching the whole file tree in constructor, but this was blowing up spectacularly when constructed for /. Thus, we're now caching lazily.

The important point about the implementation is that there is no amplification of the number of calls into the underlying file system. Each of the methods in LowercaseFileSystem calls into the underlying file system at most once.

Member Typedef Documentation

◆ Node

using LowercaseFileSystem::Node = FileSystemTrieNode<detail::LowercaseFileData>

private

Constructor & Destructor Documentation

◆ LowercaseFileSystem()

LowercaseFileSystem::LowercaseFileSystem ( FileSystem * base )

explicit

◆ ~LowercaseFileSystem()

LowercaseFileSystem::~LowercaseFileSystem ( )

virtualdefault

Member Function Documentation

◆ _displayPath()

std::string LowercaseFileSystem::_displayPath ( FileSystemPathView path ) const

overrideprivatevirtual

Implements FileSystem.

◆ _exists()

bool LowercaseFileSystem::_exists ( FileSystemPathView path ) const

overrideprivatevirtual

Implements FileSystem.

◆ _ls()

void LowercaseFileSystem::_ls	(	FileSystemPathView	path,
		std::vector< DirectoryEntry > *	entries
	)		const

overrideprivatevirtual

Implements FileSystem.

◆ _openForReading()

std::unique_ptr< InputStream > LowercaseFileSystem::_openForReading ( FileSystemPathView path ) const

overrideprivatevirtual

Implements FileSystem.

◆ _openForWriting()

std::unique_ptr< OutputStream > LowercaseFileSystem::_openForWriting ( FileSystemPathView path )

overrideprivatevirtual

Implements FileSystem.

◆ _read()

Blob LowercaseFileSystem::_read ( FileSystemPathView path ) const

overrideprivatevirtual

Implements FileSystem.

◆ _remove()

bool LowercaseFileSystem::_remove ( FileSystemPathView path )

overrideprivatevirtual

Implements FileSystem.

◆ _rename()

void LowercaseFileSystem::_rename	(	FileSystemPathView	srcPath,
		FileSystemPathView	dstPath
	)

overrideprivatevirtual

Reimplemented from FileSystem.

◆ _stat()

FileStat LowercaseFileSystem::_stat ( FileSystemPathView path ) const

overrideprivatevirtual

Implements FileSystem.

◆ _write()

void LowercaseFileSystem::_write	(	FileSystemPathView	path,
		const Blob &	data
	)

overrideprivatevirtual

Implements FileSystem.

◆ cacheInsert()

void LowercaseFileSystem::cacheInsert	(	Node *	node,
		FileSystemPathView	tail,
		FileType	type
	)		const

private

◆ cacheLs()

void LowercaseFileSystem::cacheLs	(	Node *	node,
		FileSystemPathView	basePath
	)		const

private

◆ cacheRemove()

void LowercaseFileSystem::cacheRemove ( Node * node ) const

private

◆ invalidateLs()

void LowercaseFileSystem::invalidateLs ( Node * node ) const

private

◆ locateForReading()

FileSystemPath LowercaseFileSystem::locateForReading ( FileSystemPathView path ) const

private

◆ locateForWriting()

std::tuple< FileSystemPath, LowercaseFileSystem::Node *, FileSystemPathView > LowercaseFileSystem::locateForWriting ( FileSystemPathView path )

private

◆ refresh()

void LowercaseFileSystem::refresh ( )

◆ walk()

std::tuple< FileSystemPath, LowercaseFileSystem::Node *, FileSystemPathView > LowercaseFileSystem::walk ( FileSystemPathView path ) const

private

Member Data Documentation

◆ _base

FileSystem* LowercaseFileSystem::_base = nullptr

private

◆ _trie

FileSystemTrie<detail::LowercaseFileData> LowercaseFileSystem::_trie

mutableprivate

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

src/Library/FileSystem/Lowercase/LowercaseFileSystem.h
src/Library/FileSystem/Lowercase/LowercaseFileSystem.cpp

Public Member Functions

Private Types

Private Member Functions

Private Attributes

Additional Inherited Members

Detailed Description

Member Typedef Documentation

◆ Node

Constructor & Destructor Documentation

◆ LowercaseFileSystem()

◆ ~LowercaseFileSystem()

Member Function Documentation

◆ _displayPath()

◆ _exists()

◆ _ls()

◆ _openForReading()

◆ _openForWriting()

◆ _read()

◆ _remove()

◆ _rename()

◆ _stat()

◆ _write()

◆ cacheInsert()

◆ cacheLs()

◆ cacheRemove()

◆ invalidateLs()

◆ locateForReading()

◆ locateForWriting()

◆ refresh()

◆ walk()

Member Data Documentation

◆ _base

◆ _trie