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path.cr
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path.cr
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require "crystal/system/path"
# A `Path` represents a filesystem path and allows path-handling operations
# such as querying its components as well as semantic manipulations.
#
# A path is hierarchical and composed of a sequence of directory and file name
# elements separated by a special separator or delimiter. A root component,
# that identifies a file system hierarchy, may also be present.
# The name element that is farthest from the root of the directory hierarchy is
# the name of a file or directory. The other name elements are directory names.
# A `Path` can represent a root, a root and a sequence of names, or simply one or
# more name elements.
# A `Path` is considered to be an empty path if it consists solely of one name
# element that is empty or equal to `"."`. Accessing a file using an empty path
# is equivalent to accessing the default directory of the process.
#
# # Examples
#
# ```
# Path["foo/bar/baz.cr"].parent # => Path["foo/bar"]
# Path["foo/bar/baz.cr"].basename # => "baz.cr"
# Path["./foo/../bar"].normalize # => Path["bar"]
# Path["~/bin"].expand(home: true) # => Path["/home/crystal/bin"]
# ```
#
# For now, its methods are purely lexical, there is no direct filesystem access.
#
# Path handling comes in different kinds depending on operating system:
#
# * `Path.posix()` creates a new POSIX path
# * `Path.windows()` creates a new Windows path
# * `Path.new()` means `Path.posix` on POSIX platforms and `Path.windows()`
# on Windows platforms.
#
# ```
# # On POSIX system:
# Path.new("foo", "bar", "baz.cr") == Path.posix("foo/bar/baz.cr")
# # On Windows system:
# Path.new("foo", "bar", "baz.cr") == Path.windows("foo\\bar\\baz.cr")
# ```
#
# The main differences between Windows and POSIX paths:
# * POSIX paths use forward slash (`/`) as only path separator, Windows paths use
# backslash (`\`) as default separator but also recognize forward slashes.
# * POSIX paths are generally case-sensitive, Windows paths case-insensitive
# (see `#<=>`).
# * A POSIX path is absolute if it begins with a forward slash (`/`). A Windows path
# is absolute if it starts with a drive letter and root (`C:\`).
#
# ```
# Path.posix("/foo/./bar").normalize # => Path.posix("/foo/bar")
# Path.windows("/foo/./bar").normalize # => Path.windows("\\foo\\bar")
#
# Path.posix("/foo").absolute? # => true
# Path.windows("/foo").absolute? # => false
#
# Path.posix("foo") == Path.posix("FOO") # => false
# Path.windows("foo") == Path.windows("FOO") # => true
# ```
struct Path
include Comparable(Path)
class Error < Exception
end
enum Kind : UInt8
# TODO: Consider adding NATIVE member, see https://github.com/crystal-lang/crystal/pull/5635#issuecomment-441237811
POSIX
WINDOWS
def self.native : Kind
{% if flag?(:win32) %}
WINDOWS
{% else %}
POSIX
{% end %}
end
end
# The file/directory separator characters of the current platform.
# `{'/'}` on POSIX, `{'\\', '/'}` on Windows.
SEPARATORS = separators(Kind.native)
# :nodoc:
def self.separators(kind)
if kind.windows?
{'\\', '/'}
else
{'/'}
end
end
# Creates a new `Path` of native kind.
#
# When compiling for a windows target, this is equal to `Path.windows()`,
# otherwise `Path.posix` is used.
def self.new(name : String = "") : Path
new(name.check_no_null_byte, Kind.native)
end
# :ditto:
def self.new(path : Path) : Path
path.to_native
end
# :ditto:
def self.new(name : String | Path, *parts : String | Path) : Path
new(name).join(*parts)
end
# :ditto:
def self.[](name : String | Path, *parts) : Path
new(name, *parts)
end
# :ditto:
def self.new(parts : Enumerable) : Path
new("").join(parts)
end
# :ditto:
def self.[](parts : Enumerable) : Path
new(parts)
end
# Creates a new `Path` of POSIX kind.
def self.posix(name : String = "") : Path
new(name.check_no_null_byte, Kind::POSIX)
end
# :ditto:
def self.posix(path : Path) : Path
path.to_posix
end
# :ditto:
def self.posix(name : String | Path, *parts : String | Path) : Path
posix(name).join(parts)
end
# :ditto:
def self.posix(parts : Enumerable) : Path
posix("").join(parts)
end
# Creates a new `Path` of Windows kind.
def self.windows(name : String = "") : Path
new(name.check_no_null_byte, Kind::WINDOWS)
end
# :ditto:
def self.windows(path : Path) : Path
path.to_windows
end
# :ditto:
def self.windows(name : String | Path, *parts : String | Path) : Path
windows(name).join(parts)
end
# :ditto:
def self.windows(parts : Enumerable) : Path
windows("").join(parts)
end
# :nodoc:
protected def initialize(@name : String, @kind : Kind)
end
# Internal helper method to create a new `Path` of the same kind as `self`.
private def new_instance(string : String, kind = @kind) : Path
Path.new(string, kind)
end
# Returns `true` if this is a Windows path.
def windows? : Bool
@kind.windows?
end
# Returns `true` if this is a POSIX path.
def posix? : Bool
@kind.posix?
end
# Returns `true` if this is a native path for the target platform.
def native? : Bool
@kind == Kind.native
end
# Returns all components of this path except the last one.
#
# ```
# Path["/foo/bar/file.cr"].dirname # => "/foo/bar"
# ```
def dirname : String
return "." if @name.empty?
slice = @name.to_slice
sep = self.separators.map &.ord
pos = slice.size - 1
stage = 0
slice.reverse_each do |byte|
is_separator = byte.in? sep
# The stages are ordered like this to improve performance
# Trailing separators are possible but unlikely (stage 0)
# There will probably only be one separator between filename and dirname (stage 2)
# There will probably be multiple characters in the filename which need to be skipped (stage 1)
case stage
when 1 # Wait until separator
stage += 1 if is_separator
when 2 # Remove trailing separators
break unless is_separator
when 0 # Wait until past trailing separators
stage += 1 unless is_separator
end
pos -= 1
end
case stage
when 0 # Path only consists of separators
String.new(slice[0, 1])
when 1 # Path has no parent (ex. "hello/", "C:/", "crystal")
return anchor.to_s if windows? && windows_drive?
"."
else # Path has a parent (ex. "a/a", "/home/user//", "C://Users/mmm")
return String.new(slice[0, 1]) if pos == -1
if windows? && pos == 1 && slice.unsafe_fetch(pos) === ':' && (anchor = self.anchor)
return anchor.to_s
end
String.new(slice[0, pos + 1])
end
end
# Returns the parent path of this path.
#
# If the path is empty, it returns `"."`. If the path is rooted
# and in the top-most hierarchy, the root path is returned.
#
# ```
# Path["foo/bar/file.cr"].parent # => Path["foo/bar"]
# Path["foo"].parent # => Path["."]
# Path["/foo"].parent # => Path["/"]
# Path["/"].parent # => Path["/"]
# Path[""].parent # => Path["."]
# Path["foo/bar/."].parent # => Path["foo/bar"]
# ```
def parent : Path
new_instance dirname
end
# Returns all parent paths of this path beginning with the topmost path.
#
# ```
# Path["foo/bar/file.cr"].parents # => [Path["."], Path["foo"], Path["foo/bar"]]
# ```
def parents : Array(Path)
parents = [] of Path
each_parent do |parent|
parents << parent
end
parents
end
# Yields each parent of this path beginning with the topmost parent.
#
# ```
# Path["foo/bar/file.cr"].each_parent { |parent| puts parent }
# # Path["."]
# # Path["foo"]
# # Path["foo/bar"]
# ```
def each_parent(&block : Path ->)
return if empty?
first_char = @name.char_at(0)
unless separators.includes?(first_char) || (first_char == '.' && separators.includes?(@name.byte_at?(1).try &.unsafe_chr)) || (windows? && (windows_drive? || unc_share?))
yield new_instance(".")
end
pos_memo = nil
each_part_separator_index do |start_pos, length|
# Delay yielding for each part to avoid yielding for the last part, which
# means the entire path.
if pos_memo
yield new_instance(@name.byte_slice(0, pos_memo))
end
pos_memo = start_pos + length
end
end
# Returns the last component of this path.
#
# If *suffix* is given, it is stripped from the end.
#
# In case the last component is the empty string (i.e. the path has a trailing
# separator), the second to last component is returned.
# For a path that only consists of an anchor, or an empty path, the base name
# is equivalent to the full path.
#
# ```
# Path["/foo/bar/file.cr"].basename # => "file.cr"
# Path["/foo/bar/"].basename # => "bar"
# Path["/foo/bar/."].basename # => "."
# Path["/"].basename # => "/"
# Path[""].basename # => ""
# ```
def basename(suffix : String? = nil) : String
suffix.try &.check_no_null_byte
return "" if @name.empty?
return @name if @name.size == 1 && separators.includes?(@name[0])
bytes = @name.to_slice
current = bytes.size - 1
separators = self.separators.map &.ord
# skip trailing separators
while separators.includes?(bytes[current]) && current > 0
current -= 1
end
# read suffix
if suffix && suffix.bytesize <= current && suffix == @name.byte_slice(current - suffix.bytesize + 1, suffix.bytesize)
current -= suffix.bytesize
end
# one character left?
return @name.byte_slice(0, 1) if current == 0
end_pos = {current, 1}.max
# read basename
while !separators.includes?(bytes[current]) && current > 0
current -= 1
end
start_pos = current + 1
if start_pos == 1 && !separators.includes?(bytes[current])
start_pos = 0
end
@name.byte_slice(start_pos, end_pos - start_pos + 1)
end
# Returns the extension of this path, or an empty string if it has no extension.
#
# ```
# Path["foo.cr"].extension # => ".cr"
# Path["foo"].extension # => ""
# Path["foo.tar.gz"].extension # => ".gz"
# ```
def extension : String
return "" if @name.bytesize < 3
bytes = @name.to_slice
separators = self.separators.map &.ord
# Ignore trailing separators
offset = bytes.size - 1
while bytes.unsafe_fetch(offset).in? separators
return "" if offset == 0
offset -= 1
end
# Get the first occurrence of a separator or a '.' past the trailing separators
dot_index = bytes.rindex(offset: offset) { |byte| byte === '.' || byte.in? separators }
# Return "" if '.' is the first character (ex. ".dotfile"),
# or if the '.' character follows after a separator (ex. "pathto/.dotfile")
# or if the character at the returned index is a separator (ex. "no/extension")
# or if the filename ends with a '.'
return "" unless dot_index
return "" if dot_index == 0
return "" if dot_index == offset
return "" if bytes.unsafe_fetch(dot_index - 1).in?(separators)
return "" if bytes.unsafe_fetch(dot_index).in?(separators)
String.new(bytes[dot_index, offset - dot_index + 1])
end
# Returns the last component of this path without the extension.
#
# This is equivalent to `self.basename(self.extension)`.
#
# ```
# Path["file.cr"].stem # => "file"
# Path["file.tar.gz"].stem # => "file.tar"
# Path["foo/file.cr"].stem # => "file"
# ```
def stem : String
basename(extension)
end
# Removes redundant elements from this path and returns the shortest equivalent path by purely lexical processing.
# It applies the following rules iteratively until no further processing can be done:
#
# 1. Replace multiple slashes with a single slash.
# 2. Eliminate each `.` path name element (the current directory).
# 3. Eliminate each `..` path name element (the parent directory) preceded
# by a non-`..` element along with the latter.
# 4. Eliminate `..` elements that begin a rooted path:
# that is, replace `"/.."` by `"/"` at the beginning of a path.
#
# If the path turns to be empty, the current directory (`"."`) is returned.
#
# The returned path ends in a slash only if it is the root (`"/"`, `\`, or `C:\`).
#
# See also Rob Pike: *[Lexical File Names in Plan 9 or Getting Dot-Dot Right](https://9p.io/sys/doc/lexnames.html)*
def normalize(*, remove_final_separator : Bool = true) : Path
return new_instance "." if empty?
drive, root = drive_and_root
reader = Char::Reader.new(@name)
dotdot = 0
separators = self.separators
add_separator_at_end = !remove_final_separator && ends_with_separator?
new_name = String.build do |str|
if drive
str << drive.gsub('/', '\\')
reader.pos += drive.bytesize
end
if root
str << separators[0]
reader.next_char
dotdot = str.bytesize
end
anchor_pos = str.bytesize
while (char = reader.current_char) != Char::ZERO
curr_pos = reader.pos
if separators.includes?(char)
# empty path element
reader.next_char
elsif char == '.' && (reader.pos + 1 == @name.bytesize || separators.includes?(reader.peek_next_char))
# . element
reader.next_char
elsif char == '.' && reader.next_char == '.' && (reader.pos + 1 == @name.bytesize || separators.includes?(reader.peek_next_char))
# .. element: remove to last /
reader.next_char
if str.bytesize > dotdot
str.back 1
while str.bytesize > dotdot && !separators.includes?((str.buffer + str.bytesize).value.unsafe_chr)
str.back 1
end
elsif !root
if str.bytesize > 0
str << separators[0]
end
str << ".."
dotdot = str.bytesize
end
else
reader.pos = curr_pos # make sure to reset lookahead used in previous condition
# real path element
# add slash if needed
if str.bytesize > anchor_pos && !separators.includes?((str.buffer + str.bytesize - 1).value.unsafe_chr)
str << separators[0]
end
loop do
str << char
char = reader.next_char
break if separators.includes?(char) || char == Char::ZERO
end
end
end
if str.empty?
str << '.'
end
last_char = (str.buffer + str.bytesize - 1).value.unsafe_chr
if add_separator_at_end && !separators.includes?(last_char)
str << separators[0]
end
end
new_instance new_name
end
# Yields each component of this path as a `String`.
#
# ```
# Path.new("foo/bar/").each_part # yields: "foo", "bar"
# ```
#
# See `#parts` for more examples.
def each_part(& : String ->)
each_part_separator_index do |start_pos, length|
yield @name.byte_slice(start_pos, length)
end
end
# Returns the components of this path as an `Array(String)`.
#
# ```
# Path.new("foo/bar/").parts # => ["foo", "bar"]
# Path.new("/Users/foo/bar.cr").parts # => ["/", "Users", "foo", "bar.cr"]
# Path.windows("C:\\Users\\foo\\bar.cr").parts # => ["C:\\", "Users", "foo", "bar.cr"]
# Path.posix("C:\\Users\\foo\\bar.cr").parts # => ["C:\\Users\\foo\\bar.cr"]
# ```
def parts : Array(String)
parts = [] of String
each_part do |part|
parts << part
end
parts
end
# Returns an iterator over all components of this path.
#
# ```
# parts = Path.new("foo/bar/").each_part
# parts.next # => "foo"
# parts.next # => "bar"
# parts.next # => Iterator::Stop::INSTANCE
# ```
#
# See `#parts` for more examples.
def each_part : Iterator(String)
PartIterator.new(self)
end
private def each_part_separator_index(&)
reader = Char::Reader.new(@name)
start_pos = reader.pos
if anchor = self.anchor
reader.pos = anchor.@name.bytesize
# Path is absolute, consume leading separators
while separators.includes?(reader.current_char)
break unless reader.has_next?
reader.next_char
end
start_pos = reader.pos
yield 0, start_pos
end
last_was_separator = false
separators = self.separators
while next_part = Path.next_part_separator_index(reader, last_was_separator, separators)
reader, last_was_separator, start_pos = next_part
break if reader.pos == start_pos
yield start_pos, reader.pos - start_pos
end
end
# :nodoc:
def self.next_part_separator_index(reader : Char::Reader, last_was_separator, separators)
start_pos = reader.pos
reader.each do |char|
if separators.includes?(char)
if last_was_separator
next
end
return reader, true, start_pos
elsif last_was_separator
start_pos = reader.pos
last_was_separator = false
end
end
unless last_was_separator
{reader, false, start_pos}
end
end
# :nodoc:
class PartIterator
include Iterator(String)
def initialize(@path : Path)
@reader = Char::Reader.new(@path.@name)
@last_was_separator = false
@anchor_processed = false
end
def next
start_pos = next_pos
return stop unless start_pos
return stop if start_pos == @reader.pos
@path.@name.byte_slice(start_pos, @reader.pos - start_pos)
end
private def next_pos
unless @anchor_processed
@anchor_processed = true
if anchor_pos = process_anchor
return anchor_pos
end
end
next_part = Path.next_part_separator_index(@reader, @last_was_separator, @path.separators)
return unless next_part
@reader, @last_was_separator, start_pos = next_part
start_pos
end
private def process_anchor
anchor = @path.anchor
return unless anchor
reader = @reader
reader.pos = anchor.@name.bytesize
# Path is absolute, consume leading separators
while @path.separators.includes?(reader.current_char)
return unless reader.has_next?
reader.next_char
end
@reader = reader
0
end
end
private def windows_drive?
@name.byte_at?(1) === ':' && @name.char_at(0).ascii_letter?
end
# Converts this path to a native path.
#
# * `#to_kind` performs a configurable conversion.
def to_native : Path
to_kind(Kind.native)
end
# Converts this path to a Windows path.
#
# This creates a new instance with the same string representation but with
# `Kind::WINDOWS`. If `#windows?` is true, this is a no-op.
#
# ```
# Path.posix("foo/bar").to_windows # => Path.windows("foo/bar")
# Path.windows("foo/bar").to_windows # => Path.windows("foo/bar")
# ```
#
# When *mappings* is `true` (default), forbidden characters in Windows paths are
# substituted by replacement characters when converting from a POSIX path.
# Replacements are calculated by adding `0xF000` to their codepoint.
# For example, the backslash character `U+005C` becomes `U+F05C`.
#
# ```
# Path.posix("foo\\bar").to_windows(mappings: true) # => Path.windows("foo\uF05Cbar")
# Path.posix("foo\\bar").to_windows(mappings: false) # => Path.windows("foo\\bar")
# ```
#
# * `#to_posix` performs the inverse conversion.
# * `#to_kind` performs a configurable conversion.
def to_windows(*, mappings : Bool = true) : Path
name = @name
if posix? && mappings
name = name.tr(WINDOWS_ESCAPE_CHARACTERS, WINDOWS_ESCAPED_CHARACTERS)
end
new_instance(name, Kind::WINDOWS)
end
# :nodoc:
WINDOWS_ESCAPE_CHARACTERS = %("*:<>?\\| )
# :nodoc:
WINDOWS_ESCAPED_CHARACTERS = "\uF022\uF02A\uF03A\uF03C\uF03E\uF03F\uF05C\uF07C\uF020"
# Converts this path to a POSIX path.
#
# It returns a new instance with `Kind::POSIX` and all occurrences of Windows'
# backslash file separators (`\\`) replaced by forward slash (`/`).
# If `#posix?` is true, this is a no-op.
#
# ```
# Path.windows("foo/bar\\baz").to_posix # => Path.posix("foo/bar/baz")
# Path.posix("foo/bar\\baz").to_posix # => Path.posix("foo/bar\\baz")
# ```
#
# When *mappings* is `true` (default), replacements for forbidden characters in Windows
# paths are substituted by the original characters when converting to a POSIX path.
# Originals are calculated by subtracting `0xF000` from the replacement codepoint.
# For example, the `U+F05C` becomes `U+005C`, the backslash character.
#
# ```
# Path.windows("foo\uF05Cbar").to_posix(mappings: true) # => Path.posix("foo\\bar")
# Path.windows("foo\uF05Cbar").to_posix(mappings: false) # => Path.posix("foo\uF05Cbar")
# ```
#
# * `#to_windows` performs the inverse conversion.
# * `#to_kind` performs a configurable conversion.
def to_posix(*, mappings : Bool = true) : Path
name = @name
if windows?
name = name.gsub('\\', '/')
if mappings
name = name.tr(WINDOWS_ESCAPED_CHARACTERS, WINDOWS_ESCAPE_CHARACTERS)
end
end
new_instance(name, Kind::POSIX)
end
# Converts this path to the given *kind*.
#
# See `#to_windows` and `#to_posix` for details.
#
# * `#to_native` converts to the native path semantics.
def to_kind(kind, *, mappings : Bool = true) : Path
if kind.posix?
to_posix(mappings: mappings)
else
to_windows(mappings: mappings)
end
end
# Converts this path to an absolute path. Relative paths are
# referenced from the current working directory of the process (`Dir.current`)
# unless *base* is given, in which case it will be used as the reference path.
#
# ```
# Path["foo"].expand # => Path["/current/path/foo"]
# Path["~/foo"].expand(home: "/bar") # => Path["/bar/foo"]
# Path["baz"].expand("/foo/bar") # => Path["/foo/bar/baz"]
# ```
#
# *home* specifies the home directory which `~` will expand to.
# "~" is expanded to the value passed to *home*.
# If it is `false` (default), home is not expanded.
# If `true`, it is expanded to the user's home directory (`Path.home`).
#
# If *expand_base* is `true`, *base* itself will be expanded in `Dir.current`
# if it is not an absolute path. This guarantees the method returns an absolute
# path (assuming that `Dir.current` is absolute).
def expand(base : Path | String = Dir.current, *, home : Path | String | Bool = false, expand_base = true) : Path
base = Path.new(base) unless base.is_a?(Path)
base = base.to_kind(@kind)
if base == self
# expanding base, avoid recursion
return new_instance(@name).normalize(remove_final_separator: false)
end
name = @name
if home
if name == "~"
name = resolve_home(home).to_s
elsif name.starts_with?("~/") || (windows? && name.starts_with?("~\\"))
name = resolve_home(home).join(name.byte_slice(2, name.bytesize - 2)).to_s
end
end
unless new_instance(name).absolute?
unless base.absolute? || !expand_base
base = base.expand
end
if name.empty?
expanded = base
elsif windows?
base_drive, base_root = base.drive_and_root
drive, root = new_instance(name).drive_and_root
if drive && base_root
base_relative = base_drive ? base.@name.lchop(base_drive) : base.@name
expanded = "#{drive}#{base_relative}#{separators[0]}#{name.lchop(drive)}"
elsif root
if base_drive
expanded = "#{base_drive}#{name}"
else
expanded = name
end
else
if base_root
expanded = base.join(name)
else
expanded = String.build do |io|
if drive
io << drive
elsif base_drive
io << base_drive
end
base_relative = base.@name
base_relative = base_relative.lchop(base_drive) if base_drive
name_relative = drive ? name.lchop(drive) : name
io << base_relative
io << separators[0] unless base_relative.empty?
io << name_relative
end
end
end
else
expanded = base.join(name)
end
else
expanded = name
end
expanded = new_instance(expanded) unless expanded.is_a?(Path)
expanded.normalize(remove_final_separator: false)
end
private def resolve_home(home)
case home
when String then home = Path[home]
when Bool then home = Path.home
when Path # no transformation needed
end
home.to_kind(@kind).normalize
end
# Appends the given *part* to this path and returns the joined path.
#
# ```
# Path["foo"].join("bar") # => Path["foo/bar"]
# Path["foo/"].join("/bar") # => Path["foo/bar"]
# Path["/foo/"].join("/bar/") # => Path["/foo/bar/"]
# ```
#
# Joining an empty string (`""`) appends a trailing path separator.
# In case the path already ends with a trailing separator, no additional
# separator is added.
#
# ```
# Path["a/b"].join("") # => Path["a/b/"]
# Path["a/b/"].join("") # => Path["a/b/"]
# Path["a/b/"].join("c") # => Path["a/b/c"]
# ```
def join(part) : Path
# If we are joining a single part we can use `String.new` instead of
# `String.build` which avoids an extra allocation.
# Given that `File.join(arg1, arg2)` is the most common usage
# it's good if we can optimize this case.
if part.is_a?(Path)
part = part.to_kind(@kind).to_s
else
part = part.to_s
part.check_no_null_byte
end
if @name.empty?
if part.empty?
# We could use `separators[0].to_s` but then we'd have to
# convert Char to String which involves a memory allocation
return new_instance(windows? ? "\\" : "/")
else
return new_instance(part)
end
end
bytesize = @name.bytesize + part.bytesize # bytesize of the resulting string
add_separator = false # do we need to add a separate between the parts?
part_ptr = part.to_unsafe # where do we start copying from `part`?
part_bytesize = part.bytesize # how much do we copy from `part`?
case {ends_with_separator?, starts_with_separator?(part)}
when {true, true}
# There are separators on both sides so we'll just lchop from the right part
bytesize -= 1
part_ptr += 1
part_bytesize -= 1
when {false, false}
# No separators on any side so we need to add one
bytesize += 1
add_separator = true
else
# There's at least on separator in the middle, so nothing to do
end
new_name = String.new(bytesize) do |buffer|
# Copy name
buffer.copy_from(@name.to_unsafe, @name.bytesize)
buffer += @name.bytesize
# Add separator if needed
if add_separator
buffer.value = separators[0].ord.to_u8
buffer += 1
end
# Copy the part
buffer.copy_from(part_ptr, part_bytesize)
{bytesize, @name.single_byte_optimizable? && part.single_byte_optimizable? ? bytesize : 0}
end
new_instance new_name
end
# Appends the given *parts* to this path and returns the joined path.
#
# ```
# Path["foo"].join("bar", "baz") # => Path["foo/bar/baz"]
# Path["foo/"].join("/bar/", "/baz") # => Path["foo/bar/baz"]
# Path["/foo/"].join("/bar/", "/baz/") # => Path["/foo/bar/baz/"]
# ```
#
# See `join(part)` for details.
def join(*parts) : Path
join parts
end
# Appends the given *parts* to this path and returns the joined path.
#
# ```
# Path["foo"].join("bar", "baz") # => Path["foo/bar/baz"]
# Path["foo/"].join(Path["/bar/", "/baz"]) # => Path["foo/bar/baz"]
# Path["/foo/"].join("/bar/", "/baz/") # => Path["/foo/bar/baz/"]
# ```
#
# Non-matching paths are implicitly converted to this path's kind.
#
# ```
# Path.posix("foo/bar").join(Path.windows("baz\\baq")) # => Path.posix("foo/bar/baz/baq")
# Path.windows("foo\\bar").join(Path.posix("baz/baq")) # => Path.windows("foo\\bar\\baz/baq")
# ```
#
# See `join(part)` for details.
def join(parts : Enumerable) : Path
parts.reduce(self) { |path, part| path.join(part) }
end
# Appends the given *part* to this path and returns the joined path.
#
# ```
# Path["foo"] / "bar" / "baz" # => Path["foo/bar/baz"]
# Path["foo/"] / Path["/bar/baz"] # => Path["foo/bar/baz"]
# ```
#
# See `join(part)` for details.
def /(part : Path | String) : Path
join(part)
end
# Resolves path *name* in this path's parent directory.
#
# Raises `Path::Error` if `#parent` is `nil`.
def sibling(name : Path | String) : Path
if parent = self.parent
parent.join(name)
else
raise Error.new("Can't resolve sibling for a path without parent directory")
end
end
private def empty?
@name.empty? || @name == "."
end
# Returns a relative path that is lexically equivalent to `self` when joined
# to *base* with an intervening separator.
#
# The returned path is in normalized form.
#
# That means with normalized paths `base.join(target.relative_to(base))` is
# equivalent to `target`.
#
# Returns `nil` if `self` cannot be expressed as relative to *base* or if
# knowing the current working directory would be necessary to resolve it. The
# latter can be avoided by expanding the paths first.
def relative_to?(base : Path) : Path?
base_anchor = base.anchor
target_anchor = self.anchor
# if paths have a different anchors, there can't be a relative path between
# them.
if base_anchor != target_anchor
return nil
end
# work on normalized paths otherwise we would need to backtrack on `..` parts
base = base.normalize
target = self.normalize
# check for trivial case of equal paths
if base == target
return new_instance(".")
end
base_iterator = base.each_part
target_iterator = target.each_part
if target_anchor
# process anchors, we have already established they're equal
base_iterator.next
target_iterator.next
end
# consume both paths simultaneously as long as they have identical components