Module: MFE

Defined in:
lib/mfe.rb

Overview

This module houses the main logic for MFE.

Constant Summary collapse

MLook =

Method lookup table for commands

{
	'add' => :add_cmd,
	'edit' => :edit_json,
	'show' => :show_cmd,
	'to-shell' => :cmd_to_shell,
	'rm' => :rm_cmd,
	'remove' => :rm_cmd,
}
CommandSig =

This is the character (or string) that indicates that we will be running an MFE command rather than loading and executing a user-defined command.

ENV['MFE_COMMAND_SIG'] || '-'

Instance Method Summary collapse

Instance Method Details

#add_cmd(name, *cmd) ⇒ Object

Adds a new command.



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# File 'lib/mfe.rb', line 113

def add_cmd(name, *cmd)
	if cmd.empty?
		cmd = edit_json(name)
		return false if cmd.to_s.empty?
	else
		cmd = Cmd.new(name, cmd)
	end
	cmd.save(dirname!)
end

#cmd_to_shell(name, *argv) ⇒ Object

Given a name and a list of args, this method prints a shell script that would have the effect of running the command.



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# File 'lib/mfe.rb', line 92

def cmd_to_shell(name, *argv)
	cmd = load_cmd(name)
	shell = [
		`which ENV['SHELL'] 2>/dev/null`,
		Etc.getpwuid(Process.uid).shell,
		'/bin/sh',
	].find { |shell| !shell.chomp.empty? }

	puts("#!#{shell}", 
		cmd.expand(argv))
	true
end

#dirname ⇒ Object

Returns the first viable directory for the MFE directory. If none is found, returns nil. Otherwise, it’s guaranteed to always return the same value.



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# File 'lib/mfe.rb', line 132

def dirname
	dir = dirnames.find { |d| File.directory?(d) }
	if dir
		# It's important for this to be consistent (and faster anyway).
		meta_def(:dirname) { dir }
		return dir
	end
	nil
end

#dirname! ⇒ Object

Returns the dirname, but if it’s nil, makes the directory with permissions 0700.



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# File 'lib/mfe.rb', line 144

def dirname!
	return dirname if dirname
	Dir.mkdir(dirnames.first, 0700)
	dirname
end

#dirnames ⇒ Object 



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# File 'lib/mfe.rb', line 40

def dirnames
	# Possible directories for housing mfe commands.
	@dirnames ||= [ENV['MFE_HOME'],
		(File.join(ENV['HOME'], '/.mfe') rescue nil),
		File.join(Etc.getpwuid(Process.euid).dir, '/.mfe'),
	].compact
end

#edit_json(name, *argv) ⇒ Object

Allows the user to directly edit the JSON representation of a command.



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# File 'lib/mfe.rb', line 124

def edit_json(name, *argv)
	system editor, full_path!(name)
	$?.exited?
end

#editor ⇒ Object

Returns the user’s (suspected) preferred editor.



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# File 'lib/mfe.rb', line 151

def editor
	ENV['VISUAL'] || 
	ENV['EDITOR'] || 
	'vi'  # Reasonable default.
end

#exec_cmd(name, *argv) ⇒ Object

Loads and executes a command named by name with args argv.



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# File 'lib/mfe.rb', line 54

def exec_cmd(name, *argv)
	begin
		exec load_cmd(name).expand(argv)
	rescue Errno::E2BIG
		fp = full_path name
		$stderr.puts "Couldn't execute #{name}!", "Argument list too long."
	rescue Exception => e
		fp = full_path name
		$stderr.puts "Couldn't execute #{name}! (#{e.message})"

		if !File.exist? fp
			$stderr.puts 'File does not exist.'
		elsif !File.readable? fp
			$stderr.puts 'File is not readable.'
		elsif File.directory? fp
			$stderr.puts 'It\'s a directory.'
		else
			$stderr.puts e.inspect
		end
	end
end

#full_path(name) ⇒ Object

Returns the full path for a given command with name name.



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# File 'lib/mfe.rb', line 158

def full_path(name)
	File.join(dirname, name)
end

#full_path!(name) ⇒ Object

Returns the full path for a given command with name name, and creates the path if it does not exist.



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# File 'lib/mfe.rb', line 164

def full_path!(name)
	fn = File.join(dirname!, name)
	File.open(fn, 'a').close
	fn
end

#load_cmd(name) ⇒ Object

Loads a command with the given name



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# File 'lib/mfe.rb', line 49

def load_cmd(name)
	Cmd.load full_path(name)
end

#rm_cmd(names) ⇒ Object

Removes commands! :O



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# File 'lib/mfe.rb', line 106

def rm_cmd(names)
	names.each { |name|
		File.unlink full_path(name)
	}
end

#show_cmd(*names) ⇒ Object

Given a list of command names, show_cmd will print what each one does. In the absense of a list of names, it will print all commands in the .mfe directory.



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# File 'lib/mfe.rb', line 79

def show_cmd(*names)
	if names.empty?
		names = Dir["#{dirname}/*"] - %w(. ..)
		names.map! &File.method(:basename)
	end

	names.sort.each { |name|
		puts "#{name}:  #{load_cmd(name).to_s}"
	}
end

#usage(out = $stderr) ⇒ Object 



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# File 'lib/mfe.rb', line 170

def usage(out = $stderr)
	out.puts [ "",
		"MFE, the meta front-end (#{MFEConfig::URL})",
		"Usage:",
		"#{$0} #{CommandSig} command [args ...]",
		"    Where command is one of",
		"        add name script [args ...]:",
		"            Adds a command named 'name' that executes " +
			"'script [args ...]'.",
		"        show [name(s)]", 
		"            Shows the command(s) named, or all commands if none " +
			"are named.",
		"        edit name",
		"            Runs your favorite editor on the named command.",
		"        to-shell name [args ...]",
		"            Turns the user-defined command into a shell script.",
		"#{$0} your_command [args ...]",
		"    Runs the user-defined command named 'your_command' with the " +
			"specified\n    arguments.",
		"#{$0} ['-h'|'-help'|'--help']",
		"    This help screen.",
		"See the README for more info about usage and influential " +
			"environment\nvariables.",
	]
end

#version_string ⇒ Object 



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# File 'lib/mfe.rb', line 196

def version_string
	"MFE, version #{MFEConfig::Version}."
end