Results for: "remove_const"

Resolv 

Windows NT

PrettyPrint

This class implements a pretty printing algorithm. It finds line breaks and nice indentations for grouped structure.

By default, the class assumes that primitive elements are strings and each byte in the strings have single column in width. But it can be used for other situations by giving suitable arguments for some methods:

There are several candidate uses:

Bugs

Report any bugs at bugs.ruby-lang.org

References

Christian Lindig, Strictly Pretty, March 2000, lindig.github.io/papers/strictly-pretty-2000.pdf

Philip Wadler, A prettier printer, March 1998, homepages.inf.ed.ac.uk/wadler/topics/language-design.html#prettier

Author

Tanaka Akira <akr@fsij.org>

Resolv

Resolv is a thread-aware DNS resolver library written in Ruby. Resolv can handle multiple DNS requests concurrently without blocking the entire Ruby interpreter.

See also resolv-replace.rb to replace the libc resolver with Resolv.

Resolv can look up various DNS resources using the DNS module directly.

Examples:

p Resolv.getaddress "www.ruby-lang.org"
p Resolv.getname "210.251.121.214"

Resolv::DNS.open do |dns|
  ress = dns.getresources "www.ruby-lang.org", Resolv::DNS::Resource::IN::A
  p ress.map(&:address)
  ress = dns.getresources "ruby-lang.org", Resolv::DNS::Resource::IN::MX
  p ress.map { |r| [r.exchange.to_s, r.preference] }
end

Bugs

Tempfile

A utility class for managing temporary files.

There are two kind of methods of creating a temporary file:

Tempfile.create creates a usual File object. The timing of file deletion is predictable. Also, it supports open-and-unlink technique which removes the temporary file immediately after creation.

Tempfile.new and Tempfile.open creates a Tempfile object. The created file is removed by the GC (finalizer). The timing of file deletion is not predictable.

Synopsis 

require 'tempfile'

# Tempfile.create with a block
# The filename are choosen automatically.
# (You can specify the prefix and suffix of the filename by an optional argument.)
Tempfile.create {|f|
  f.puts "foo"
  f.rewind
  f.read                # => "foo\n"
}                       # The file is removed at block exit.

# Tempfile.create without a block
# You need to unlink the file in non-block form.
f = Tempfile.create
f.puts "foo"
f.close
File.unlink(f.path)     # You need to unlink the file.

# Tempfile.create(anonymous: true) without a block
f = Tempfile.create(anonymous: true)
# The file is already removed because anonymous.
f.path                  # => "/tmp/"  (no filename since no file)
f.puts "foo"
f.rewind
f.read                  # => "foo\n"
f.close

# Tempfile.create(anonymous: true) with a block
Tempfile.create(anonymous: true) {|f|
  # The file is already removed because anonymous.
  f.path                # => "/tmp/"  (no filename since no file)
  f.puts "foo"
  f.rewind
  f.read                # => "foo\n"
}

# Not recommended: Tempfile.new without a block
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

About Tempfile.new and Tempfile.open

This section does not apply to Tempfile.create because it returns a File object (not a Tempfile object).

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.

A Tempfile object has a finalizer to remove the temporary file. This means that the temporary file is removed via GC. This can cause several problems:

There are legacy good practices for Tempfile.new and Tempfile.open as follows.

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 it’s unnecessary to explicitly delete a Tempfile after use, though it’s a good practice to do so: not explicitly deleting unused Tempfiles can potentially leave behind a large number of temp files 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.create('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.

Also, this guarantees the temporary file is removed even if Ruby exits abnormally. The OS reclaims the storage for the temporary file when the file is closed or the Ruby process exits (normally or abnormally).

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.

‘Tempfile.create(anonymous: true)` supports this behavior. It also works on Windows.

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.

WeakRef

Weak Reference class that allows a referenced object to be garbage-collected.

A WeakRef may be used exactly like the object it references.

Usage:

foo = Object.new            # create a new object instance
p foo.to_s                  # original's class
foo = WeakRef.new(foo)      # reassign foo with WeakRef instance
p foo.to_s                  # should be same class
GC.start                    # start the garbage collector
p foo.to_s                  # should raise exception (recycled)

RegexpError

Raised when given an invalid regexp expression.

Regexp.new("?")

raises the exception:

RegexpError: target of repeat operator is not specified: /?/

ThreadGroup

ThreadGroup provides a means of keeping track of a number of threads as a group.

A given Thread object can only belong to one ThreadGroup at a time; adding a thread to a new group will remove it from any previous group.

Newly created threads belong to the same group as the thread from which they were created.

ThreadError

Raised when an invalid operation is attempted on a thread.

For example, when no other thread has been started:

Thread.stop

This will raises the following exception:

ThreadError: stopping only thread
note: use sleep to stop forever

Thread

Threads are the Ruby implementation for a concurrent programming model.

Programs that require multiple threads of execution are a perfect candidate for Ruby’s Thread class.

For example, we can create a new thread separate from the main thread’s execution using ::new.

thr = Thread.new { puts "What's the big deal" }

Then we are able to pause the execution of the main thread and allow our new thread to finish, using join:

thr.join #=> "What's the big deal"

If we don’t call thr.join before the main thread terminates, then all other threads including thr will be killed.

Alternatively, you can use an array for handling multiple threads at once, like in the following example:

threads = []
threads << Thread.new { puts "What's the big deal" }
threads << Thread.new { 3.times { puts "Threads are fun!" } }

After creating a few threads we wait for them all to finish consecutively.

threads.each { |thr| thr.join }

To retrieve the last value of a thread, use value

thr = Thread.new { sleep 1; "Useful value" }
thr.value #=> "Useful value"

Thread initialization

In order to create new threads, Ruby provides ::new, ::start, and ::fork. A block must be provided with each of these methods, otherwise a ThreadError will be raised.

When subclassing the Thread class, the initialize method of your subclass will be ignored by ::start and ::fork. Otherwise, be sure to call super in your initialize method.

Thread termination

For terminating threads, Ruby provides a variety of ways to do this.

The class method ::kill, is meant to exit a given thread:

thr = Thread.new { sleep }
Thread.kill(thr) # sends exit() to thr

Alternatively, you can use the instance method exit, or any of its aliases kill or terminate.

thr.exit

Thread status

Ruby provides a few instance methods for querying the state of a given thread. To get a string with the current thread’s state use status

thr = Thread.new { sleep }
thr.status # => "sleep"
thr.exit
thr.status # => false

You can also use alive? to tell if the thread is running or sleeping, and stop? if the thread is dead or sleeping.

Thread variables and scope

Since threads are created with blocks, the same rules apply to other Ruby blocks for variable scope. Any local variables created within this block are accessible to only this thread.

Fiber-local vs. Thread-local

Each fiber has its own bucket for Thread#[] storage. When you set a new fiber-local it is only accessible within this Fiber. To illustrate:

Thread.new {
  Thread.current[:foo] = "bar"
  Fiber.new {
    p Thread.current[:foo] # => nil
  }.resume
}.join

This example uses [] for getting and []= for setting fiber-locals, you can also use keys to list the fiber-locals for a given thread and key? to check if a fiber-local exists.

When it comes to thread-locals, they are accessible within the entire scope of the thread. Given the following example:

Thread.new{
  Thread.current.thread_variable_set(:foo, 1)
  p Thread.current.thread_variable_get(:foo) # => 1
  Fiber.new{
    Thread.current.thread_variable_set(:foo, 2)
    p Thread.current.thread_variable_get(:foo) # => 2
  }.resume
  p Thread.current.thread_variable_get(:foo)   # => 2
}.join

You can see that the thread-local :foo carried over into the fiber and was changed to 2 by the end of the thread.

This example makes use of thread_variable_set to create new thread-locals, and thread_variable_get to reference them.

There is also thread_variables to list all thread-locals, and thread_variable? to check if a given thread-local exists.

Exception handling

When an unhandled exception is raised inside a thread, it will terminate. By default, this exception will not propagate to other threads. The exception is stored and when another thread calls value or join, the exception will be re-raised in that thread.

t = Thread.new{ raise 'something went wrong' }
t.value #=> RuntimeError: something went wrong

An exception can be raised from outside the thread using the Thread#raise instance method, which takes the same parameters as Kernel#raise.

Setting Thread.abort_on_exception = true, Thread#abort_on_exception = true, or $DEBUG = true will cause a subsequent unhandled exception raised in a thread to be automatically re-raised in the main thread.

With the addition of the class method ::handle_interrupt, you can now handle exceptions asynchronously with threads.

Scheduling

Ruby provides a few ways to support scheduling threads in your program.

The first way is by using the class method ::stop, to put the current running thread to sleep and schedule the execution of another thread.

Once a thread is asleep, you can use the instance method wakeup to mark your thread as eligible for scheduling.

You can also try ::pass, which attempts to pass execution to another thread but is dependent on the OS whether a running thread will switch or not. The same goes for priority, which lets you hint to the thread scheduler which threads you want to take precedence when passing execution. This method is also dependent on the OS and may be ignored on some platforms.

Gem

RubyGems is the Ruby standard for publishing and managing third party libraries.

For user documentation, see:

For gem developer documentation see:

Further RubyGems documentation can be found at:

RubyGems Plugins

RubyGems will load plugins in the latest version of each installed gem or $LOAD_PATH. Plugins must be named ‘rubygems_plugin’ (.rb, .so, etc) and placed at the root of your gem’s require_path. Plugins are installed at a special location and loaded on boot.

For an example plugin, see the Graph gem which adds a gem graph command.

RubyGems Defaults, Packaging

RubyGems defaults are stored in lib/rubygems/defaults.rb. If you’re packaging RubyGems or implementing Ruby you can change RubyGems’ defaults.

For RubyGems packagers, provide lib/rubygems/defaults/operating_system.rb and override any defaults from lib/rubygems/defaults.rb.

For Ruby implementers, provide lib/rubygems/defaults/#{RUBY_ENGINE}.rb and override any defaults from lib/rubygems/defaults.rb.

If you need RubyGems to perform extra work on install or uninstall, your defaults override file can set pre/post install and uninstall hooks. See Gem::pre_install, Gem::pre_uninstall, Gem::post_install, Gem::post_uninstall.

Bugs

You can submit bugs to the RubyGems bug tracker on GitHub

Credits

RubyGems is currently maintained by Eric Hodel.

RubyGems was originally developed at RubyConf 2003 by:

Contributors:

(If your name is missing, PLEASE let us know!)

License

See LICENSE.txt for permissions.

Thanks!

-The RubyGems Team

Provides 3 methods for declaring when something is going away.

+deprecate(name, repl, year, month)+:

Indicate something may be removed on/after a certain date.

+rubygems_deprecate(name, replacement=:none)+:

Indicate something will be removed in the next major RubyGems version,
and (optionally) a replacement for it.

rubygems_deprecate_command:

Indicate a RubyGems command (in +lib/rubygems/commands/*.rb+) will be
removed in the next RubyGems version.

Also provides skip_during for temporarily turning off deprecation warnings. This is intended to be used in the test suite, so deprecation warnings don’t cause test failures if you need to make sure stderr is otherwise empty.

Example usage of deprecate and rubygems_deprecate:

class Legacy
  def self.some_class_method
    # ...
  end

  def some_instance_method
    # ...
  end

  def some_old_method
    # ...
  end

  extend Gem::Deprecate
  deprecate :some_instance_method, "X.z", 2011, 4
  rubygems_deprecate :some_old_method, "Modern#some_new_method"

  class << self
    extend Gem::Deprecate
    deprecate :some_class_method, :none, 2011, 4
  end
end

Example usage of rubygems_deprecate_command:

class Gem::Commands::QueryCommand < Gem::Command
  extend Gem::Deprecate
  rubygems_deprecate_command

  # ...
end

Example usage of skip_during:

class TestSomething < Gem::Testcase
  def test_some_thing_with_deprecations
    Gem::Deprecate.skip_during do
      actual_stdout, actual_stderr = capture_output do
        Gem.something_deprecated
      end
      assert_empty actual_stdout
      assert_equal(expected, actual_stderr)
    end
  end
end

MakeMakefile

mkmf.rb is used by Ruby C extensions to generate a Makefile which will correctly compile and link the C extension to Ruby and a third-party library.

SecureRandom

Secure random number generator interface.

This library is an interface to secure random number generators which are suitable for generating session keys in HTTP cookies, etc.

You can use this library in your application by requiring it:

require 'securerandom'

It supports the following secure random number generators:

SecureRandom is extended by the Random::Formatter module which defines the following methods:

These methods are usable as class methods of SecureRandom such as SecureRandom.hex.

If a secure random number generator is not available, NotImplementedError is raised.

Prism::Relocation::CodeUnitColumnsField

A field representing the start and end code unit columns for a specific encoding.

Gem::Commands::ContentsCommand

No documentation available

Gem::Commands::InstallCommand

Gem installer command line tool

See ‘gem help install`

Gem::Commands::UninstallCommand

Gem uninstaller command line tool

See ‘gem help uninstall`

Gem::Resolver::InstalledSpecification

An InstalledSpecification represents a gem that is already installed locally.

Gem::S3URISigner::ConfigurationError

No documentation available

IO::EINPROGRESSWaitReadable

exception to wait for reading by EINPROGRESS. see IO.select.

DidYouMean::RequirePathChecker

No documentation available

Net::HTTPServerError

Parent class for server error (5xx) HTTP response classes.

A server error response indicates that the server failed to fulfill a request.

References:

Net::HTTPAlreadyReported

Response class for Already Reported (WebDAV) responses (status code 208).

The Already Reported (WebDAV) response indicates that the server has received the request, and that the members of a DAV binding have already been enumerated in a preceding part of the (multi-status) response, and are not being included again.

References:

Net::HTTPPermanentRedirect

Response class for Permanent Redirect responses (status code 308).

This and all future requests should be directed to the given URI.

References:

Net::HTTPPaymentRequired

Response class for Payment Required responses (status code 402).

Reserved for future use.

References:

Net::HTTPLengthRequired

Response class for Length Required responses (status code 411).

The request did not specify the length of its content, which is required by the requested resource.

References:

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