# A utility class for managing temporary files. When you create a Tempfile
# object, it will create a temporary file with a unique filename. A Tempfile
# objects behaves just like a File object, and you can perform all the usual
# file operations on it: reading data, writing data, changing its permissions,
# etc. So although this class does not explicitly document all instance methods
# supported by File, you can in fact call any File instance method on a Tempfile
# object.
#
# ## Synopsis
#
#     require 'tempfile'
#
#     file = Tempfile.new('foo')
#     file.path      # => A unique filename in the OS's temp directory,
#                    #    e.g.: "/tmp/foo.24722.0"
#                    #    This filename contains 'foo' in its basename.
#     file.write("hello world")
#     file.rewind
#     file.read      # => "hello world"
#     file.close
#     file.unlink    # deletes the temp file
#
# ## Good practices
#
# ### Explicit close
#
# When a Tempfile object is garbage collected, or when the Ruby interpreter
# exits, its associated temporary file is automatically deleted. This means
# that's it's unnecessary to explicitly delete a Tempfile after use, though it's
# good practice to do so: not explicitly deleting unused Tempfiles can
# potentially leave behind large amounts of tempfiles on the filesystem until
# they're garbage collected. The existence of these temp files can make it
# harder to determine a new Tempfile filename.
#
# Therefore, one should always call #unlink or close in an ensure block, like
# this:
#
#     file = Tempfile.new('foo')
#     begin
#        # ...do something with file...
#     ensure
#        file.close
#        file.unlink   # deletes the temp file
#     end
#
# Tempfile.create { ... } exists for this purpose and is more convenient to use.
# Note that Tempfile.create returns a File instance instead of a Tempfile, which
# also avoids the overhead and complications of delegation.
#
#     Tempfile.open('foo') do |file|
#        # ...do something with file...
#     end
#
# ### Unlink after creation
#
# On POSIX systems, it's possible to unlink a file right after creating it, and
# before closing it. This removes the filesystem entry without closing the file
# handle, so it ensures that only the processes that already had the file handle
# open can access the file's contents. It's strongly recommended that you do
# this if you do not want any other processes to be able to read from or write
# to the Tempfile, and you do not need to know the Tempfile's filename either.
#
# For example, a practical use case for unlink-after-creation would be this: you
# need a large byte buffer that's too large to comfortably fit in RAM, e.g. when
# you're writing a web server and you want to buffer the client's file upload
# data.
#
# Please refer to #unlink for more information and a code example.
#
# ## Minor notes
#
# Tempfile's filename picking method is both thread-safe and inter-process-safe:
# it guarantees that no other threads or processes will pick the same filename.
#
# Tempfile itself however may not be entirely thread-safe. If you access the
# same Tempfile object from multiple threads then you should protect it with a
# mutex.
class Tempfile < File
  # Creates a temporary file as a usual File object (not a Tempfile). It does not
  # use finalizer and delegation, which makes it more efficient and reliable.
  #
  # If no block is given, this is similar to Tempfile.new except creating File
  # instead of Tempfile. In that case, the created file is not removed
  # automatically. You should use File.unlink to remove it.
  #
  # If a block is given, then a File object will be constructed, and the block is
  # invoked with the object as the argument. The File object will be automatically
  # closed and the temporary file is removed after the block terminates, releasing
  # all resources that the block created. The call returns the value of the block.
  #
  # In any case, all arguments (`basename`, `tmpdir`, `mode`, and `**options`)
  # will be treated the same as for Tempfile.new.
  #
  #     Tempfile.create('foo', '/home/temp') do |f|
  #        # ... do something with f ...
  #     end
  #
  def self.create: (?String basename, ?String? tmpdir, ?mode: Integer, **untyped) -> File
                 | [A] (?String basename, ?String? tmpdir, ?mode: Integer, **untyped) { (File) -> A } -> A

  # Creates a new Tempfile.
  #
  # This method is not recommended and exists mostly for backward compatibility.
  # Please use Tempfile.create instead, which avoids the cost of delegation, does
  # not rely on a finalizer, and also unlinks the file when given a block.
  #
  # Tempfile.open is still appropriate if you need the Tempfile to be unlinked by
  # a finalizer and you cannot explicitly know where in the program the Tempfile
  # can be unlinked safely.
  #
  # If no block is given, this is a synonym for Tempfile.new.
  #
  # If a block is given, then a Tempfile object will be constructed, and the block
  # is run with the Tempfile object as argument. The Tempfile object will be
  # automatically closed after the block terminates. However, the file will
  # **not** be unlinked and needs to be manually unlinked with Tempfile#close! or
  # Tempfile#unlink. The finalizer will try to unlink but should not be relied
  # upon as it can keep the file on the disk much longer than intended. For
  # instance, on CRuby, finalizers can be delayed due to conservative stack
  # scanning and references left in unused memory.
  #
  # The call returns the value of the block.
  #
  # In any case, all arguments (`*args`) will be passed to Tempfile.new.
  #
  #     Tempfile.open('foo', '/home/temp') do |f|
  #        # ... do something with f ...
  #     end
  #
  #     # Equivalent:
  #     f = Tempfile.open('foo', '/home/temp')
  #     begin
  #        # ... do something with f ...
  #     ensure
  #        f.close
  #     end
  #
  def self.open: (*untyped args, **untyped) -> Tempfile
               | [A] (*untyped args, **untyped) { (Tempfile) -> A } -> A

  public

  # Closes the file. If `unlink_now` is true, then the file will be unlinked
  # (deleted) after closing. Of course, you can choose to later call #unlink if
  # you do not unlink it now.
  #
  # If you don't explicitly unlink the temporary file, the removal will be delayed
  # until the object is finalized.
  #
  def close: (?boolish unlink_now) -> void

  # Closes and unlinks (deletes) the file. Has the same effect as called
  # `close(true)`.
  #
  def close!: () -> void

  alias delete unlink

  def inspect: () -> String

  alias length size

  # Opens or reopens the file with mode "r+".
  #
  def open: () -> File

  # Returns the full path name of the temporary file. This will be nil if #unlink
  # has been called.
  #
  def path: () -> String?

  # Returns the size of the temporary file.  As a side effect, the IO buffer is
  # flushed before determining the size.
  #
  def size: () -> Integer

  # Unlinks (deletes) the file from the filesystem. One should always unlink the
  # file after using it, as is explained in the "Explicit close" good practice
  # section in the Tempfile overview:
  #
  #     file = Tempfile.new('foo')
  #     begin
  #        # ...do something with file...
  #     ensure
  #        file.close
  #        file.unlink   # deletes the temp file
  #     end
  #
  # ### Unlink-before-close
  #
  # On POSIX systems it's possible to unlink a file before closing it. This
  # practice is explained in detail in the Tempfile overview (section "Unlink
  # after creation"); please refer there for more information.
  #
  # However, unlink-before-close may not be supported on non-POSIX operating
  # systems. Microsoft Windows is the most notable case: unlinking a non-closed
  # file will result in an error, which this method will silently ignore. If you
  # want to practice unlink-before-close whenever possible, then you should write
  # code like this:
  #
  #     file = Tempfile.new('foo')
  #     file.unlink   # On Windows this silently fails.
  #     begin
  #        # ... do something with file ...
  #     ensure
  #        file.close!   # Closes the file handle. If the file wasn't unlinked
  #                      # because #unlink failed, then this method will attempt
  #                      # to do so again.
  #     end
  #
  def unlink: () -> void

  class Remover
    public

    def call: (*untyped args) -> void

    private

    def initialize: (::Tempfile tmpfile) -> void
  end

  private

  # Creates a temporary file with permissions 0600 (= only readable and writable
  # by the owner) and opens it with mode "w+".
  #
  # It is recommended to use Tempfile.create { ... } instead when possible,
  # because that method avoids the cost of delegation and does not rely on a
  # finalizer to close and unlink the file, which is unreliable.
  #
  # The `basename` parameter is used to determine the name of the temporary file.
  # You can either pass a String or an Array with 2 String elements. In the former
  # form, the temporary file's base name will begin with the given string. In the
  # latter form, the temporary file's base name will begin with the array's first
  # element, and end with the second element. For example:
  #
  #     file = Tempfile.new('hello')
  #     file.path  # => something like: "/tmp/hello2843-8392-92849382--0"
  #
  #     # Use the Array form to enforce an extension in the filename:
  #     file = Tempfile.new(['hello', '.jpg'])
  #     file.path  # => something like: "/tmp/hello2843-8392-92849382--0.jpg"
  #
  # The temporary file will be placed in the directory as specified by the
  # `tmpdir` parameter. By default, this is `Dir.tmpdir`.
  #
  #     file = Tempfile.new('hello', '/home/aisaka')
  #     file.path  # => something like: "/home/aisaka/hello2843-8392-92849382--0"
  #
  # You can also pass an options hash. Under the hood, Tempfile creates the
  # temporary file using `File.open`. These options will be passed to `File.open`.
  # This is mostly useful for specifying encoding options, e.g.:
  #
  #     Tempfile.new('hello', '/home/aisaka', encoding: 'ascii-8bit')
  #
  #     # You can also omit the 'tmpdir' parameter:
  #     Tempfile.new('hello', encoding: 'ascii-8bit')
  #
  # Note: `mode` keyword argument, as accepted by Tempfile, can only be numeric,
  # combination of the modes defined in File::Constants.
  #
  # ### Exceptions
  #
  # If Tempfile.new cannot find a unique filename within a limited number of
  # tries, then it will raise an exception.
  #
  def self.new: (?String basename, ?String? tmpdir, ?mode: Integer, **untyped) -> instance
              | [A] (?String basename, ?String? tmpdir, ?mode: Integer, **untyped) { (instance) -> A } -> A
end