Adds aProc as a finalizer, to be called after obj was destroyed. The object ID of the obj will be passed as an argument to aProc. If aProc is a lambda or method, make sure it can be called with a single argument.
The return value is an array [0, aProc]
.
The two recommended patterns are to either create the finaliser proc in a non-instance method where it can safely capture the needed state, or to use a custom callable object that stores the needed state explicitly as instance variables.
class Foo def initialize(data_needed_for_finalization) ObjectSpace.define_finalizer(self, self.class.create_finalizer(data_needed_for_finalization)) end def self.create_finalizer(data_needed_for_finalization) proc { puts "finalizing #{data_needed_for_finalization}" } end end class Bar class Remover def initialize(data_needed_for_finalization) @data_needed_for_finalization = data_needed_for_finalization end def call(id) puts "finalizing #{@data_needed_for_finalization}" end end def initialize(data_needed_for_finalization) ObjectSpace.define_finalizer(self, Remover.new(data_needed_for_finalization)) end end
Note that if your finalizer references the object to be finalized it will never be run on GC
, although it will still be run at exit. You will get a warning if you capture the object to be finalized as the receiver of the finalizer.
class CapturesSelf def initialize(name) ObjectSpace.define_finalizer(self, proc { # this finalizer will only be run on exit puts "finalizing #{name}" }) end end
Also note that finalization can be unpredictable and is never guaranteed to be run except on exit.
Removes all finalizers for obj.
Parse a YAML
string in yaml
. Returns the Psych::Nodes::Stream
. This method can handle multiple YAML
documents contained in yaml
. filename
is used in the exception message if a Psych::SyntaxError
is raised.
If a block is given, a Psych::Nodes::Document
node will be yielded to the block as it’s being parsed.
Raises a Psych::SyntaxError
when a YAML
syntax error is detected.
Example:
Psych.parse_stream("---\n - a\n - b") # => #<Psych::Nodes::Stream:0x00> Psych.parse_stream("--- a\n--- b") do |node| node # => #<Psych::Nodes::Document:0x00> end begin Psych.parse_stream("--- `", filename: "file.txt") rescue Psych::SyntaxError => ex ex.file # => 'file.txt' ex.message # => "(file.txt): found character that cannot start any token" end
Raises a TypeError
when NilClass
is passed.
See Psych::Nodes
for more information about YAML
AST.
Dump a list of objects as separate documents to a document stream.
Example:
Psych.dump_stream("foo\n ", {}) # => "--- ! \"foo\\n \"\n--- {}\n"
Load multiple documents given in yaml
. Returns the parsed documents as a list. If a block is given, each document will be converted to Ruby and passed to the block during parsing
Example:
Psych.load_stream("--- foo\n...\n--- bar\n...") # => ['foo', 'bar'] list = [] Psych.load_stream("--- foo\n...\n--- bar\n...") do |ruby| list << ruby end list # => ['foo', 'bar']
Returns true if using experimental feature Variable Width Allocation, false otherwise.
Creates hard links; returns nil
.
Arguments src
and dest
should be interpretable as paths.
If src
is the path to a file and dest
does not exist, creates a hard link at dest
pointing to src
:
FileUtils.touch('src0.txt') File.exist?('dest0.txt') # => false FileUtils.link_entry('src0.txt', 'dest0.txt') File.file?('dest0.txt') # => true
If src
is the path to a directory and dest
does not exist, recursively creates hard links at dest
pointing to paths in src
:
FileUtils.mkdir_p(['src1/dir0', 'src1/dir1']) src_file_paths = [ 'src1/dir0/t0.txt', 'src1/dir0/t1.txt', 'src1/dir1/t2.txt', 'src1/dir1/t3.txt', ] FileUtils.touch(src_file_paths) File.directory?('dest1') # => true FileUtils.link_entry('src1', 'dest1') File.file?('dest1/dir0/t0.txt') # => true File.file?('dest1/dir0/t1.txt') # => true File.file?('dest1/dir1/t2.txt') # => true File.file?('dest1/dir1/t3.txt') # => true
Keyword arguments:
dereference_root: true
- dereferences src
if it is a symbolic link.
remove_destination: true
- removes dest
before creating links.
Raises an exception if dest
is the path to an existing file or directory and keyword argument remove_destination: true
is not given.
Related: FileUtils.ln
(has different options).
Creates hard links; returns nil
.
Arguments src
and dest
should be interpretable as paths.
If src
is the path to a file and dest
does not exist, creates a hard link at dest
pointing to src
:
FileUtils.touch('src0.txt') File.exist?('dest0.txt') # => false FileUtils.link_entry('src0.txt', 'dest0.txt') File.file?('dest0.txt') # => true
If src
is the path to a directory and dest
does not exist, recursively creates hard links at dest
pointing to paths in src
:
FileUtils.mkdir_p(['src1/dir0', 'src1/dir1']) src_file_paths = [ 'src1/dir0/t0.txt', 'src1/dir0/t1.txt', 'src1/dir1/t2.txt', 'src1/dir1/t3.txt', ] FileUtils.touch(src_file_paths) File.directory?('dest1') # => true FileUtils.link_entry('src1', 'dest1') File.file?('dest1/dir0/t0.txt') # => true File.file?('dest1/dir0/t1.txt') # => true File.file?('dest1/dir1/t2.txt') # => true File.file?('dest1/dir1/t3.txt') # => true
Keyword arguments:
dereference_root: true
- dereferences src
if it is a symbolic link.
remove_destination: true
- removes dest
before creating links.
Raises an exception if dest
is the path to an existing file or directory and keyword argument remove_destination: true
is not given.
Related: FileUtils.ln
(has different options).
Copies IO stream src
to IO stream dest
via IO.copy_stream
.
Related: methods for copying.
Copies IO stream src
to IO stream dest
via IO.copy_stream
.
Related: methods for copying.
Returns true
if the contents of streams a
and b
are identical, false
otherwise.
Arguments a
and b
should be interpretable as a path.
Related: FileUtils.compare_file
.
Returns true
if the contents of streams a
and b
are identical, false
otherwise.
Arguments a
and b
should be interpretable as a path.
Related: FileUtils.compare_file
.
Takes a hash as its argument. The key is a symbol or an array of symbols. These symbols correspond to method names, instance variable names, or constant names (see def_delegator
). The value is the accessor to which the methods will be delegated.
Takes a hash as its argument. The key is a symbol or an array of symbols. These symbols correspond to method names. The value is the accessor to which the methods will be delegated.
Open3.pipeline_start
starts a list of commands as a pipeline. No pipes are created for stdin of the first command and stdout of the last command.
Open3.pipeline_start(cmd1, cmd2, ... [, opts]) {|wait_threads| ... } wait_threads = Open3.pipeline_start(cmd1, cmd2, ... [, opts]) ...
Each cmd is a string or an array. If it is an array, the elements are passed to Process.spawn
.
cmd: commandline command line string which is passed to a shell [env, commandline, opts] command line string which is passed to a shell [env, cmdname, arg1, ..., opts] command name and one or more arguments (no shell) [env, [cmdname, argv0], arg1, ..., opts] command name and arguments including argv[0] (no shell) Note that env and opts are optional, as for Process.spawn.
Example:
# Run xeyes in 10 seconds. Open3.pipeline_start("xeyes") {|ts| sleep 10 t = ts[0] Process.kill("TERM", t.pid) p t.value #=> #<Process::Status: pid 911 SIGTERM (signal 15)> } # Convert pdf to ps and send it to a printer. # Collect error message of pdftops and lpr. pdf_file = "paper.pdf" printer = "printer-name" err_r, err_w = IO.pipe Open3.pipeline_start(["pdftops", pdf_file, "-"], ["lpr", "-P#{printer}"], :err=>err_w) {|ts| err_w.close p err_r.read # error messages of pdftops and lpr. }
Open3.pipeline_start
starts a list of commands as a pipeline. No pipes are created for stdin of the first command and stdout of the last command.
Open3.pipeline_start(cmd1, cmd2, ... [, opts]) {|wait_threads| ... } wait_threads = Open3.pipeline_start(cmd1, cmd2, ... [, opts]) ...
Each cmd is a string or an array. If it is an array, the elements are passed to Process.spawn
.
cmd: commandline command line string which is passed to a shell [env, commandline, opts] command line string which is passed to a shell [env, cmdname, arg1, ..., opts] command name and one or more arguments (no shell) [env, [cmdname, argv0], arg1, ..., opts] command name and arguments including argv[0] (no shell) Note that env and opts are optional, as for Process.spawn.
Example:
# Run xeyes in 10 seconds. Open3.pipeline_start("xeyes") {|ts| sleep 10 t = ts[0] Process.kill("TERM", t.pid) p t.value #=> #<Process::Status: pid 911 SIGTERM (signal 15)> } # Convert pdf to ps and send it to a printer. # Collect error message of pdftops and lpr. pdf_file = "paper.pdf" printer = "printer-name" err_r, err_w = IO.pipe Open3.pipeline_start(["pdftops", pdf_file, "-"], ["lpr", "-P#{printer}"], :err=>err_w) {|ts| err_w.close p err_r.read # error messages of pdftops and lpr. }
Adds a pre-install hook that will be passed an Gem::Installer
instance when Gem::Installer#install
is called. If the hook returns false
then the install will be aborted.
Adds a pre-uninstall hook that will be passed an Gem::Uninstaller
instance and the spec that will be uninstalled when Gem::Uninstaller#uninstall
is called
Safely write a file in binary mode on all platforms.
Returns the status of the last executed child process in the current thread.
Process.wait Process.spawn("ruby", "-e", "exit 13") Process.last_status #=> #<Process::Status: pid 4825 exit 13>
If no child process has ever been executed in the current thread, this returns nil
.
Process.last_status #=> nil