mirror of
https://github.com/samsonjs/csc360-a1-shell.git
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132 lines
3.2 KiB
Ruby
132 lines
3.2 KiB
Ruby
begin
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require "readline"
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rescue LoadError
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require "reline"
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end
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require "shell/builtins"
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require "shell/colours"
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require "shell/job_control"
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require "shell/logger"
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require "shell/word_expander"
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module Shell
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class REPL
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include Colours
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attr_reader :builtins, :job_control, :logger, :options, :word_expander
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attr_accessor :precmd_hook
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def initialize(builtins: nil, job_control: nil, logger: nil, word_expander: nil)
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logger ||= Logger.instance
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job_control ||= JobControl.new(logger: logger)
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builtins ||= Builtins.new(job_control: job_control)
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word_expander ||= WordExpander.new
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@builtins = builtins
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@job_control = job_control
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@logger = logger
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@options = {}
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@word_expander = word_expander
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end
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def start(options: nil)
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@options = options || {}
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job_control.trap_sigchld
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add_to_history = true
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status = 0
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loop do
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precmd_hook&.call
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print "#{red(status)} " unless status.zero?
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line = Readline.readline(prompt(Dir.pwd), add_to_history)
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Readline::HISTORY.pop if line.nil? || line.strip.empty?
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status = process_command(line)
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end
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end
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def process_command(line)
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exit 0 if line.nil? # EOF, ctrl-d
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return 0 if line.strip.empty? # no input, no-op
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logger.verbose "Processing command: #{line.inspect}"
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commands = parse_line(line)
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result = nil
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commands.each do |command|
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args = word_expander.expand(command)
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program = args.shift
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logger.verbose "Parsed command: #{program} #{args.inspect}"
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if builtins.builtin?(program)
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logger.verbose "Executing builtin #{program}"
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result = builtins.exec(program, args)
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else
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logger.verbose "Shelling out for #{program}"
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result = job_control.exec_command(program, args)
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end
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end
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result
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rescue Errno => e
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warn "#{red("[ERROR]")} #{e.message}"
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-1
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end
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# Looks like this: /path/to/somewhere%
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def prompt(pwd)
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"#{blue(pwd)}#{white("%")} #{CLEAR}"
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end
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def parse_line(line)
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commands = []
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command = "".dup
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state = :unquoted
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line.each_char do |c|
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case state
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when :unquoted
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case c
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when ";"
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commands << command
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command = "".dup
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when "'"
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command << c
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state = :single_quoted
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when "\""
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command << c
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state = :double_quoted
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when "\\"
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command << c
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state = :escaped
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else
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command << c
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end
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when :single_quoted
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command << c
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state = :unquoted if c == "'"
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when :double_quoted
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case c
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when "\\"
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state = :double_quoted_escape
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else
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command << c
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end
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state = :unquoted if c == "\""
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when :double_quoted_escape
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command << "\\"
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command << c
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state = :double_quoted
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when :escaped
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command << c
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state = :unquoted
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else
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raise "Unknown state #{state}"
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end
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end
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commands << command
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commands
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end
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end
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end
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