require 'rbconfig' module Kernel # Sets $VERBOSE to nil for the duration of the block and back to its original value afterwards. # # silence_warnings do # value = noisy_call # no warning voiced # end # # noisy_call # warning voiced def silence_warnings with_warnings(nil) { yield } end # Sets $VERBOSE to true for the duration of the block and back to its original value afterwards. def enable_warnings with_warnings(true) { yield } end # Sets $VERBOSE for the duration of the block and back to its original value afterwards. def with_warnings(flag) old_verbose, $VERBOSE = $VERBOSE, flag yield ensure $VERBOSE = old_verbose end # For compatibility def silence_stderr #:nodoc: silence_stream(STDERR) { yield } end # Silences any stream for the duration of the block. # # silence_stream(STDOUT) do # puts 'This will never be seen' # end # # puts 'But this will' def silence_stream(stream) old_stream = stream.dup stream.reopen(RbConfig::CONFIG['host_os'] =~ /mswin|mingw/ ? 'NUL:' : '/dev/null') stream.sync = true yield ensure stream.reopen(old_stream) end # Blocks and ignores any exception passed as argument if raised within the block. # # suppress(ZeroDivisionError) do # 1/0 # puts "This code is NOT reached" # end # # puts "This code gets executed and nothing related to ZeroDivisionError was seen" def suppress(*exception_classes) begin yield rescue Exception => e raise unless exception_classes.any? { |cls| e.kind_of?(cls) } end end # Captures the given stream and returns it: # # stream = capture(:stdout) { puts "Cool" } # stream # => "Cool\n" # def capture(stream) begin stream = stream.to_s eval "$#{stream} = StringIO.new" yield result = eval("$#{stream}").string ensure eval("$#{stream} = #{stream.upcase}") end result end alias :silence :capture # Silences both STDOUT and STDERR, even for subprocesses. # # quietly { system 'bundle install' } # def quietly silence_stream(STDOUT) do silence_stream(STDERR) do yield end end end end