Module: MemFs

Defined in:
lib/memfs.rb,
lib/memfs/io.rb,
lib/memfs/dir.rb,
lib/memfs/file.rb,
lib/memfs/version.rb,
lib/memfs/fake/file.rb,
lib/memfs/file/stat.rb,
lib/memfs/fake/entry.rb,
lib/memfs/file_system.rb,
lib/memfs/fake/symlink.rb,
lib/memfs/fake/directory.rb,
lib/memfs/fake/file/content.rb,
lib/memfs/filesystem_access.rb

Overview

Provides a clean way to interact with a fake file system.

Examples:

Calling activate with a block.

MemFs.activate do
  Dir.mkdir '/hello_world'
  # /hello_world exists here, in memory
end
# /hello_world doesn't exist and has never been on the real FS

Calling activate! and deactivate!.

MemFs.activate!
  # The fake file system is running here
MemFs.deactivate!
# Everything back to normal

Defined Under Namespace

Modules: Fake, FilesystemAccess Classes: Dir, File, FileSystem, IO

Constant Summary collapse

OriginalDir =

Keeps track of the original Ruby Dir class.

::Dir
OriginalFile =

Keeps track of the original Ruby File class.

::File
OriginalIO =

Keeps track of the original Ruby IO class.

::IO
VERSION = 
'2.0.0'

Class Method Summary collapse

Class Method Details

.activate { ... } ⇒ Object

Calls the given block with MemFs activated.

The advantage of using #activate against #activate! is that, in case an exception occurs, MemFs is deactivated.

Examples:

MemFs.activate do
  Dir.mkdir '/hello_world'
  # /hello_world exists here, in memory
end
# /hello_world doesn't exist and has never been on the real FS

Exception in activate block.

MemFs.activate do
  raise "Some Error"
end
# Still back to the original Ruby classes

Yields:

  • with no argument.

Returns:

  • nothing.



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# File 'lib/memfs.rb', line 136

def activate
  activate!
  yield
ensure
  deactivate!
end

.activate!(clear: true) ⇒ Object

Note:

Don't forget to call #deactivate! to disable the fake file system, you may have some issues in your scripts or tests otherwise.

Activates the fake file system.

Examples:

MemFs.activate!
Dir.mkdir '/hello_world'
# /hello_world exists here, in memory
MemFs.deactivate!
# /hello_world doesn't exist and has never been on the real FS

Returns:

  • nothing.

See Also:

  • #deactivate!


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# File 'lib/memfs.rb', line 158

def activate!(clear: true)
  Object.class_eval do
    remove_const :Dir
    remove_const :File
    remove_const :IO

    const_set :Dir, MemFs::Dir
    const_set :IO, MemFs::IO
    const_set :File, MemFs::File
  end

  MemFs::FileSystem.instance.clear! if clear
end

.deactivate! ⇒ Object

Note:

This method should always be called when using activate!

Deactivates the fake file system.

Returns:

  • nothing.

See Also:

  • #activate!


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# File 'lib/memfs.rb', line 179

def deactivate!
  Object.class_eval do
    remove_const :Dir
    remove_const :File
    remove_const :IO

    const_set :Dir, MemFs::OriginalDir
    const_set :IO, MemFs::OriginalIO
    const_set :File, MemFs::OriginalFile
  end
end

.default_platform_root ⇒ Object

Returns the default platform root based on the current OS



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# File 'lib/memfs.rb', line 54

def self.default_platform_root
  if windows?
    # Normalize drive letter to uppercase
    OriginalFile.expand_path('/').sub(/\A([a-z]):/) { "#{::Regexp.last_match(1).upcase}:" }
  else
    '/'
  end
end

.halt ⇒ Object

Switches back to the original file system, calls the given block (if any), and switches back afterwards.

If a block is given, all file & dir operations (like reading dir contents or requiring files) will operate on the original fs.

Examples:

MemFs.halt do
  puts Dir.getwd
end

Returns:

  • nothing



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# File 'lib/memfs.rb', line 203

def halt
  deactivate!

  yield if block_given?
ensure
  activate!(clear: false)
end

.normalize_path(path) ⇒ Object

Normalize path for consistent handling rubocop:disable Metrics/AbcSize, Metrics/CyclomaticComplexity, Metrics/MethodLength rubocop:disable Metrics/PerceivedComplexity



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# File 'lib/memfs.rb', line 74

def self.normalize_path(path)
  return path unless path.is_a?(String)

  # Reject UNC paths
  fail ArgumentError, "UNC paths are not supported: #{path}" if path.start_with?('\\\\', '//')

  # Convert backslashes to forward slashes
  path = path.tr('\\', '/')

  return path unless windows?

  # Normalize drive letter to uppercase
  path = path.sub(/\A([a-z]):/) { "#{::Regexp.last_match(1).upcase}:" }

  # Handle drive-relative paths like 'D:foo' or 'D:.' (no slash after colon)
  # and bare drive letters like 'D:' (current directory on drive D)
  # Convert to absolute paths since our fake fs doesn't support per-drive working directories
  if path.match?(/\A[A-Z]:\z/) # Bare drive like 'D:'
    path = "#{path}/"
  elsif path.match?(%r{\A[A-Z]:[^/]}) # Drive-relative like 'D:foo' or 'D:.'
    path = path.sub(/\A([A-Z]):/, '\1:/')
  end

  # Convert bare '/' to platform root on Windows
  if path == '/'
    platform_root
  elsif path.start_with?('/') && !path.match?(%r{\A[A-Z]:/})
    # Convert '/foo' to 'D:/foo' on Windows
    "#{platform_root}#{path[1..]}"
  else
    path
  end
end

.platform_root ⇒ Object

Returns the platform-specific root path (e.g., '/' on Unix, 'D:/' on Windows)



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# File 'lib/memfs.rb', line 39

def self.platform_root
  @platform_root || default_platform_root
end

.platform_root=(value) ⇒ Object

Allows setting a custom platform root (mainly for testing)



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# File 'lib/memfs.rb', line 44

def self.platform_root=(value)
  @platform_root = value
end

.reset_platform_root! ⇒ Object

Resets platform_root to the default value



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# File 'lib/memfs.rb', line 49

def self.reset_platform_root!
  @platform_root = nil
end

.root_path?(path) ⇒ Boolean

Check if a path is the root path (handles both '/' and 'D:/')

Returns:

  • (Boolean) 


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# File 'lib/memfs.rb', line 64

def self.root_path?(path)
  return false if path.nil?

  normalized = normalize_path(path)
  normalized == platform_root || normalized == '/'
end

.ruby_version_gte?(version) ⇒ Boolean

:nodoc:

Returns:

  • (Boolean) 


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# File 'lib/memfs.rb', line 30

def self.ruby_version_gte?(version) # :nodoc:
  Gem::Version.new(RUBY_VERSION) >= Gem::Version.new(version)
end

.touch(*paths) ⇒ Object

Creates a file and all its parent directories.

Parameters:

  • path: —

    The path of the file to create.

Returns:

  • nothing.



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# File 'lib/memfs.rb', line 217

def touch(*paths)
  fail 'Always call MemFs.touch inside a MemFs active context.' if ::File != MemFs::File

  paths.each do |path|
    FileUtils.mkdir_p File.dirname(path)
    FileUtils.touch path
  end
end

.windows? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/memfs.rb', line 34

def self.windows?
  /mswin|bccwin|mingw/ =~ RUBY_PLATFORM
end