module GnuplotRB

##

# Just a new error name

class GnuplotError < ArgumentError

end

##

# Mixin for classes that need to run subprocess and

# handle errors from its stderr.

module ErrorHandling

##

# Check if there were errors in previous commands.

# Throws GnuplotError in case of any errors.

def check_errors(raw: false)

return if @err_array.empty?

command = ''

rest = ''

@semaphore.synchronize do

command = @err_array.first

rest = @err_array[1..-1].join('; ')

@err_array.clear

end

message = if raw

"#{command};#{rest}}"

else

"Error in previous command (\"#{command}\"): \"#{rest}\""

end

fail GnuplotError, message

end

private

##

# Start new thread that will read stderr given as stream

# and add errors into @err_array.

def handle_stderr(stream)

@err_array = []

# synchronize access to @err_array

@semaphore = Mutex.new

Thread.new do

until (line = stream.gets).nil?

line.strip!

@semaphore.synchronize { @err_array << line if line.size > 3 }

end

end

end

end

end