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file.cr
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file.cr
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require "crystal/system/file"
class File < IO::FileDescriptor
# The file/directory separator character. `'/'` in Unix, `'\\'` in Windows.
SEPARATOR = {% if flag?(:windows) %}
'\\'
{% else %}
'/'
{% end %}
# The file/directory separator string. `"/"` in Unix, `"\\"` in Windows.
SEPARATOR_STRING = {% if flag?(:windows) %}
"\\"
{% else %}
"/"
{% end %}
# :nodoc:
DEFAULT_CREATE_MODE = LibC::S_IRUSR | LibC::S_IWUSR | LibC::S_IRGRP | LibC::S_IROTH
include Crystal::System::File
# This constructor is provided for subclasses to be able to initialize an
# `IO::FileDescriptor` with a *path* and *fd*.
private def initialize(@path, fd, blocking = false, encoding = nil, invalid = nil)
self.set_encoding(encoding, invalid: invalid) if encoding
super(fd, blocking)
end
def self.new(filename : String, mode = "r", perm = DEFAULT_CREATE_MODE, encoding = nil, invalid = nil)
fd = Crystal::System::File.open(filename, mode, perm)
new(filename, fd, blocking: true, encoding: encoding, invalid: invalid)
end
getter path : String
# Returns a `File::Stat` object for the file given by *path* or returns `nil`
# if the file does not exist. Raises `Errno` in case of an error. In case of
# a symbolic link it is followed and information about the target is returned.
#
# ```
# File.write("foo", "foo")
# File.stat?("foo").try(&.size) # => 3
# File.stat?("non_existent") # => nil
# ```
def self.stat?(path : String) : Stat?
Crystal::System::File.stat?(path)
end
# Returns a `File::Stat` object for the file given by *path* or returns `nil`
# if the file does not exist. Raises `Errno` in case of an error. In case of
# a symbolic link information about the link itself is returned.
#
# ```
# File.write("foo", "foo")
# File.lstat?("foo").try(&.size) # => 3
#
# File.symlink("foo", "bar")
# File.lstat?("bar").try(&.symlink?) # => true
#
# File.lstat?("non_existent") # => nil
# ```
def self.lstat?(path : String) : Stat?
Crystal::System::File.lstat?(path)
end
# Returns a `File::Stat` object for the file given by *path* or raises
# `Errno` in case of an error. In case of a symbolic link
# it is followed and information about the target is returned.
#
# ```
# File.write("foo", "foo")
# File.stat("foo").size # => 3
# File.stat("foo").mtime # => 2015-09-23 06:24:19 UTC
# ```
def self.stat(path) : Stat
stat?(path) || raise Errno.new("Unable to get stat for #{path.inspect}")
end
# Returns a `File::Stat` object for the file given by *path* or raises
# `Errno` in case of an error. In case of a symbolic link
# information about the link itself is returned.
#
# ```
# File.write("foo", "foo")
# File.lstat("foo").size # => 3
# File.lstat("foo").mtime # => 2015-09-23 06:24:19 UTC
# ```
def self.lstat(path) : Stat
lstat?(path) || raise Errno.new("Unable to get stat for #{path.inspect}")
end
# Returns `true` if *path* exists else returns `false`
#
# ```
# File.delete("foo") if File.exists?("foo")
# File.exists?("foo") # => false
# File.write("foo", "foo")
# File.exists?("foo") # => true
# ```
def self.exists?(path) : Bool
Crystal::System::File.exists?(path)
end
# Returns the size of *filename* bytes. Raises `Errno` if the file at *path*
# does not exist.
#
# ```
# File.size("foo") # raises Errno
# File.write("foo", "foo")
# File.size("foo") # => 3
# ```
def self.size(filename) : UInt64
stat(filename).size
rescue ex : Errno
raise Errno.new("Error determining size of #{filename.inspect}", ex.errno)
end
# Returns `true` if the file at *path* is empty, otherwise returns `false`.
# Raises `Errno` if the file at *path* does not exist.
#
# ```
# File.write("foo", "")
# File.empty?("foo") # => true
# File.write("foo", "foo")
# File.empty?("foo") # => false
# ```
def self.empty?(path) : Bool
size(path) == 0
end
# Returns `true` if *path* is readable by the real user id of this process else returns `false`.
#
# ```
# File.write("foo", "foo")
# File.readable?("foo") # => true
# ```
def self.readable?(path) : Bool
Crystal::System::File.readable?(path)
end
# Returns `true` if *path* is writable by the real user id of this process else returns `false`.
#
# ```
# File.write("foo", "foo")
# File.writable?("foo") # => true
# ```
def self.writable?(path) : Bool
Crystal::System::File.writable?(path)
end
# Returns `true` if *path* is executable by the real user id of this process else returns `false`.
#
# ```
# File.write("foo", "foo")
# File.executable?("foo") # => false
# ```
def self.executable?(path) : Bool
Crystal::System::File.executable?(path)
end
# Returns `true` if given *path* exists and is a file.
#
# ```
# File.write("foo", "")
# Dir.mkdir("dir1")
# File.file?("foo") # => true
# File.file?("dir1") # => false
# File.file?("foobar") # => false
# ```
def self.file?(path) : Bool
if stat = stat?(path)
stat.file?
else
false
end
end
# Returns `true` if the given *path* exists and is a directory.
#
# ```
# File.write("foo", "")
# Dir.mkdir("dir2")
# File.directory?("foo") # => false
# File.directory?("dir2") # => true
# File.directory?("foobar") # => false
# ```
def self.directory?(path) : Bool
Dir.exists?(path)
end
# Returns all components of the given *path* except the last one.
#
# ```
# File.dirname("/foo/bar/file.cr") # => "/foo/bar"
# ```
def self.dirname(path) : String
path.check_no_null_byte
index = path.rindex SEPARATOR
if index
if index == 0
SEPARATOR_STRING
else
path[0, index]
end
else
"."
end
end
# Returns the last component of the given *path*.
#
# ```
# File.basename("/foo/bar/file.cr") # => "file.cr"
# ```
def self.basename(path) : String
return "" if path.bytesize == 0
return SEPARATOR_STRING if path == SEPARATOR_STRING
path.check_no_null_byte
last = path.size - 1
last -= 1 if path[last] == SEPARATOR
index = path.rindex SEPARATOR, last
if index
path[index + 1, last - index]
else
path
end
end
# Returns the last component of the given *path*.
#
# If *suffix* is present at the end of *path*, it is removed.
#
# ```
# File.basename("/foo/bar/file.cr", ".cr") # => "file"
# ```
def self.basename(path, suffix) : String
suffix.check_no_null_byte
basename(path).chomp(suffix)
end
# Changes the owner of the specified file.
#
# ```
# File.chown("/foo/bar/baz.cr", 1001, 100)
# File.chown("/foo/bar", gid: 100)
# ```
#
# Unless *follow_symlinks* is set to `true`, then the owner symlink itself will
# be changed, otherwise the owner of the symlink destination file will be
# changed. For example, assuming symlinks as `foo -> bar -> baz`:
#
# ```
# File.chown("foo", gid: 100) # changes foo's gid
# File.chown("foo", gid: 100, follow_symlinks: true) # changes baz's gid
# ```
def self.chown(path, uid : Int = -1, gid : Int = -1, follow_symlinks = false)
Crystal::System::File.chown(path, uid, gid, follow_symlinks)
end
# Changes the permissions of the specified file.
#
# Symlinks are dereferenced, so that only the permissions of the symlink
# destination are changed, never the permissions of the symlink itself.
#
# ```
# File.chmod("foo", 0o755)
# File.stat("foo").perm # => 0o755
#
# File.chmod("foo", 0o700)
# File.stat("foo").perm # => 0o700
# ```
def self.chmod(path, mode : Int)
Crystal::System::File.chmod(path, mode)
end
# Delete the file at *path*. Deleting non-existent file will raise an exception.
#
# ```
# File.write("foo", "")
# File.delete("./foo")
# File.delete("./bar") # raises Errno (No such file or directory)
# ```
def self.delete(path)
Crystal::System::File.delete(path)
end
# Returns *filename*'s extension, or an empty string if it has no extension.
#
# ```
# File.extname("foo.cr") # => ".cr"
# ```
def self.extname(filename) : String
filename.check_no_null_byte
dot_index = filename.rindex('.')
if dot_index && dot_index != filename.size - 1 && filename[dot_index - 1] != SEPARATOR
filename[dot_index, filename.size - dot_index]
else
""
end
end
# Converts *path* to an absolute path. Relative paths are
# referenced from the current working directory of the process unless
# *dir* is given, in which case it will be used as the starting point.
#
# ```
# File.expand_path("foo") # => "/home/.../foo"
# File.expand_path("~/crystal/foo") # => "/home/crystal/foo"
# File.expand_path("baz", "/foo/bar") # => "/foo/bar/baz"
# ```
def self.expand_path(path, dir = nil) : String
path.check_no_null_byte
if path.starts_with?('~')
home = ENV["HOME"]
home = home.chomp('/') unless home == "/"
if path.size >= 2 && path[1] == SEPARATOR
path = home + path[1..-1]
elsif path.size < 2
return home
end
end
unless path.starts_with?(SEPARATOR)
dir = dir ? expand_path(dir) : Dir.current
path = "#{dir}#{SEPARATOR}#{path}"
end
parts = path.split(SEPARATOR)
items = [] of String
parts.each do |part|
case part
when "", "."
# Nothing
when ".."
items.pop?
else
items << part
end
end
String.build do |str|
{% if !flag?(:windows) %}
str << SEPARATOR_STRING
{% end %}
items.join SEPARATOR_STRING, str
end
end
class BadPatternError < Exception
end
# Matches *path* against *pattern*.
#
# The pattern syntax is similar to shell filename globbing. It may contain the following metacharacters:
#
# * `*` matches an unlimited number of arbitrary characters excluding `/`.
# * `"*"` matches all regular files.
# * `"c*"` matches all files beginning with `c`.
# * `"*c"` matches all files ending with `c`.
# * `"*c*"` matches all files that have `c` in them (including at the beginning or end).
# * `**` matches an unlimited number of arbitrary charachters including `/`.
# * `?` matches any one charachter excluding `/`.
# * character sets:
# * `[abc]` matches any one of these character.
# * `[^abc]` matches any one character other than these.
# * `[a-z]` matches any one charachter in the range.
# * `{a,b}` matches subpattern `a` or `b`.
# * `\\` escapes the next character.
#
# NOTE: Only `/` is recognized as path separator in both *pattern* and *path*.
def self.match?(pattern : String, path : String)
expanded_patterns = [] of String
File.expand_brace_pattern(pattern, expanded_patterns)
expanded_patterns.each do |expanded_pattern|
return true if match_single_pattern(expanded_pattern, path)
end
false
end
private def self.match_single_pattern(pattern : String, path : String)
# linear-time algorithm adapted from https://research.swtch.com/glob
preader = Char::Reader.new(pattern)
sreader = Char::Reader.new(path)
next_ppos = 0
next_spos = 0
strlen = path.bytesize
escaped = false
while true
pnext = preader.has_next?
snext = sreader.has_next?
return true unless pnext || snext
if pnext
pchar = preader.current_char
char = sreader.current_char
case {pchar, escaped}
when {'\\', false}
escaped = true
preader.next_char
next
when {'?', false}
if snext && char != '/'
preader.next_char
sreader.next_char
next
end
when {'*', false}
double_star = preader.peek_next_char == '*'
if char == '/' && !double_star
preader.next_char
next_spos = 0
next
else
next_ppos = preader.pos
next_spos = sreader.pos + sreader.current_char_width
preader.next_char
preader.next_char if double_star
next
end
when {'[', false}
pnext = preader.has_next?
character_matched = false
character_set_open = true
escaped = false
inverted = false
case preader.peek_next_char
when '^'
inverted = true
preader.next_char
when ']'
raise BadPatternError.new "Invalid character set: empty character set"
end
while pnext
pchar = preader.next_char
case {pchar, escaped}
when {'\\', false}
escaped = true
when {']', false}
character_set_open = false
break
when {'-', false}
raise BadPatternError.new "Invalid character set: missing range start"
else
escaped = false
if preader.has_next? && preader.peek_next_char == '-'
preader.next_char
range_end = preader.next_char
case range_end
when ']'
raise BadPatternError.new "Invalid character set: missing range end"
when '\\'
range_end = preader.next_char
end
range = (pchar..range_end)
character_matched = true if range.includes?(char)
elsif char == pchar
character_matched = true
end
end
pnext = preader.has_next?
false
end
raise BadPatternError.new "Invalid character set: unterminated character set" if character_set_open
if character_matched != inverted && snext
preader.next_char
sreader.next_char
next
end
else
escaped = false
if snext && sreader.current_char == pchar
preader.next_char
sreader.next_char
next
end
end
end
if 0 < next_spos <= strlen
preader.pos = next_ppos
sreader.pos = next_spos
next
end
raise BadPatternError.new "Empty escape character" if escaped
return false
end
end
# :nodoc:
def self.expand_brace_pattern(pattern : String, expanded)
reader = Char::Reader.new(pattern)
lbrace = nil
rbrace = nil
alt_start = nil
alternatives = [] of String
nest = 0
escaped = false
reader.each do |char|
case {char, escaped}
when {'{', false}
lbrace = reader.pos if nest == 0
nest += 1
when {'}', false}
nest -= 1
if nest == 0
rbrace = reader.pos
start = (alt_start || lbrace).not_nil! + 1
alternatives << pattern.byte_slice(start, reader.pos - start)
break
end
when {',', false}
if nest == 1
start = (alt_start || lbrace).not_nil! + 1
alternatives << pattern.byte_slice(start, reader.pos - start)
alt_start = reader.pos
end
when {'\\', false}
escaped = true
else
escaped = false
end
end
if lbrace && rbrace
front = pattern.byte_slice(0, lbrace)
back = pattern.byte_slice(rbrace + 1)
alternatives.each do |alt|
brace_pattern = {front, alt, back}.join
expand_brace_pattern brace_pattern, expanded
end
else
expanded << pattern
end
end
# Resolves the real path of *path* by following symbolic links.
def self.real_path(path) : String
Crystal::System::File.real_path(path)
end
# Creates a new link (also known as a hard link) at *new_path* to an existing file
# given by *old_path*.
def self.link(old_path, new_path)
Crystal::System::File.link(old_path, new_path)
end
# Creates a symbolic link at *new_path* to an existing file given by *old_path.
def self.symlink(old_path, new_path)
Crystal::System::File.symlink(old_path, new_path)
end
# Returns `true` if the *path* is a symbolic link.
def self.symlink?(path) : Bool
if stat = lstat?(path)
stat.symlink?
else
false
end
end
# Opens the file named by *filename*. If a file is being created, its initial
# permissions may be set using the *perm* parameter.
def self.open(filename, mode = "r", perm = DEFAULT_CREATE_MODE, encoding = nil, invalid = nil) : self
new filename, mode, perm, encoding, invalid
end
# Opens the file named by *filename*. If a file is being created, its initial
# permissions may be set using the *perm* parameter. Then given block will be passed the opened
# file as an argument, the file will be automatically closed when the block returns.
def self.open(filename, mode = "r", perm = DEFAULT_CREATE_MODE, encoding = nil, invalid = nil)
file = new filename, mode, perm, encoding, invalid
begin
yield file
ensure
file.close
end
end
# Returns the content of *filename* as a string.
#
# ```
# File.write("bar", "foo")
# File.read("bar") # => "foo"
# ```
def self.read(filename, encoding = nil, invalid = nil) : String
open(filename, "r") do |file|
if encoding
file.set_encoding(encoding, invalid: invalid)
file.gets_to_end
else
# We try to read a string with an initialize capacity
# equal to the file's size, but the size might not be
# correct or even be zero (for example for /proc files)
size = file.size.to_i
size = 256 if size == 0
String.build(size) do |io|
IO.copy(file, io)
end
end
end
end
# Yields each line in *filename* to the given block.
#
# ```
# File.write("foobar", "foo\nbar")
#
# array = [] of String
# File.each_line("foobar") do |line|
# array << line
# end
# array # => ["foo", "bar"]
# ```
def self.each_line(filename, encoding = nil, invalid = nil, chomp = true)
open(filename, "r", encoding: encoding, invalid: invalid) do |file|
file.each_line(chomp: chomp) do |line|
yield line
end
end
end
# Returns an `Iterator` for each line in *filename*.
def self.each_line(filename, encoding = nil, invalid = nil, chomp = true)
open(filename, "r", encoding: encoding, invalid: invalid).each_line(chomp: chomp)
end
# Returns all lines in *filename* as an array of strings.
#
# ```
# File.write("foobar", "foo\nbar")
# File.read_lines("foobar") # => ["foo", "bar"]
# ```
def self.read_lines(filename, encoding = nil, invalid = nil, chomp = true) : Array(String)
lines = [] of String
each_line(filename, encoding: encoding, invalid: invalid, chomp: chomp) do |line|
lines << line
end
lines
end
# Write the given *content* to *filename*.
#
# An existing file will be overwritten, else a file will be created.
#
# ```
# File.write("foo", "bar")
# ```
#
# NOTE: If the content is a `Slice(UInt8)`, those bytes will be written.
# If it's an `IO`, all bytes from the `IO` will be written.
# Otherwise, the string representation of *content* will be written
# (the result of invoking `to_s` on *content*).
def self.write(filename, content, perm = DEFAULT_CREATE_MODE, encoding = nil, invalid = nil)
open(filename, "w", perm, encoding: encoding, invalid: invalid) do |file|
case content
when Bytes
file.write(content)
when IO
IO.copy(content, file)
else
file.print(content)
end
end
end
# Returns a new string formed by joining the strings using `File::SEPARATOR`.
#
# ```
# File.join("foo", "bar", "baz") # => "foo/bar/baz"
# File.join("foo/", "/bar/", "/baz") # => "foo/bar/baz"
# File.join("/foo/", "/bar/", "/baz/") # => "/foo/bar/baz/"
# ```
def self.join(*parts) : String
join parts
end
# Returns a new string formed by joining the strings using `File::SEPARATOR`.
#
# ```
# File.join({"foo", "bar", "baz"}) # => "foo/bar/baz"
# File.join({"foo/", "/bar/", "/baz"}) # => "foo/bar/baz"
# File.join(["/foo/", "/bar/", "/baz/"]) # => "/foo/bar/baz/"
# ```
def self.join(parts : Array | Tuple) : String
String.build do |str|
parts.each_with_index do |part, index|
part.check_no_null_byte
str << SEPARATOR if index > 0
byte_start = 0
byte_count = part.bytesize
if index > 0 && part.starts_with?(SEPARATOR)
byte_start += 1
byte_count -= 1
end
if index != parts.size - 1 && part.ends_with?(SEPARATOR)
byte_count -= 1
end
str.write part.unsafe_byte_slice(byte_start, byte_count)
end
end
end
# Moves *old_filename* to *new_filename*.
#
# ```
# File.write("afile", "foo")
# File.exists?("afile") # => true
#
# File.rename("afile", "afile.cr")
# File.exists?("afile") # => false
# File.exists?("afile.cr") # => true
# ```
def self.rename(old_filename, new_filename) : Nil
Crystal::System::File.rename(old_filename, new_filename)
end
# Sets the access and modification times of *filename*.
def self.utime(atime : Time, mtime : Time, filename : String) : Nil
Crystal::System::File.utime(atime, mtime, filename)
end
# Attempts to set the access and modification times of the file named
# in the *filename* parameter to the value given in *time*.
#
# If the file does not exist, it will be created.
def self.touch(filename : String, time : Time = Time.now)
open(filename, "a") { } unless exists?(filename)
utime time, time, filename
end
# Return the size in bytes of the currently opened file.
def size
stat.size
end
# Truncates the file to the specified *size*. Requires that the current file is opened
# for writing.
def truncate(size = 0) : Nil
flush
system_truncate(size)
end
# Yields an `IO` to read a section inside this file.
# Multiple sections can be read concurrently.
def read_at(offset, bytesize, &block)
self_bytesize = self.size
unless 0 <= offset <= self_bytesize
raise ArgumentError.new("Offset out of bounds")
end
if bytesize < 0
raise ArgumentError.new("Negative bytesize")
end
unless 0 <= offset + bytesize <= self_bytesize
raise ArgumentError.new("Bytesize out of bounds")
end
io = PReader.new(fd, offset, bytesize)
yield io ensure io.close
end
def inspect(io)
io << "#<File:" << @path
io << " (closed)" if closed?
io << ">"
io
end
# TODO: use fcntl/lockf instead of flock (which doesn't lock over NFS)
# TODO: always use non-blocking locks, yield fiber until resource becomes available
def flock_shared(blocking = true)
flock_shared blocking
begin
yield
ensure
flock_unlock
end
end
# Place a shared advisory lock. More than one process may hold a shared lock for a given file at a given time.
# `Errno::EWOULDBLOCK` is raised if *blocking* is set to `false` and an existing exclusive lock is set.
def flock_shared(blocking = true)
system_flock_shared(blocking)
end
def flock_exclusive(blocking = true)
flock_exclusive blocking
begin
yield
ensure
flock_unlock
end
end
# Place an exclusive advisory lock. Only one process may hold an exclusive lock for a given file at a given time.
# `Errno::EWOULDBLOCK` is raised if *blocking* is set to `false` and any existing lock is set.
def flock_exclusive(blocking = true)
system_flock_exclusive(blocking)
end
# Remove an existing advisory lock held by this process.
def flock_unlock
system_flock_unlock
end
end
require "./file/*"