Class: RubySnooper::TraceWriter

Inherits:
Object
  • Object
show all
Defined in:
lib/ruby_snooper/trace_writer.rb

Defined Under Namespace

Classes: Line, Return

Instance Method Summary collapse

Constructor Details

#initialize(method_name, caller_path) ⇒ TraceWriter

Returns a new instance of TraceWriter.



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# File 'lib/ruby_snooper/trace_writer.rb', line 5

def initialize(method_name, caller_path)
  @method_name = method_name
  @caller_path = caller_path
  @source_cache = {}
  @lines = []
  @return = nil
end

Instance Method Details

#code_for(filename) ⇒ Object 



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# File 'lib/ruby_snooper/trace_writer.rb', line 13

def code_for(filename)
  @source_cache[filename] ||= IO.readlines(filename, chomp: true)
end

#print ⇒ Object 



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# File 'lib/ruby_snooper/trace_writer.rb', line 17

def print
  @lines.each(&:print)
  @return.print
end

#trace_point ⇒ Object 



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# File 'lib/ruby_snooper/trace_writer.rb', line 22

def trace_point
  @trace_point ||= TracePoint.new(:call, :line, :return) do |tp|
    next if @method_name != tp.method_id
    next if tp.path != @caller_path

    local_variables = tp.binding.local_variables.map do |name|
      [name, tp.binding.local_variable_get(name).inspect]
    end.to_h

    if @lines.count > 0
      new_variables = local_variables.select { |key,value| !@lines.last.local_variables.has_key?(key) }
      modified_variables = local_variables.select {|key, value| @lines.last.local_variables.has_key?(key) && value != @lines.last.local_variables[key] }
    end

    case tp.event
    when :call, :line
      @lines << Line.new(
        tp.method_id,
        tp.event,
        tp.lineno,
        Time.now,
        code_for(tp.path)[tp.lineno - 1],
        local_variables,
        new_variables,
        modified_variables,
        tp.path,
      )
    when :return
      @return = Return.new(
        tp.method_id,
        tp.event,
        tp.lineno,
        Time.now,
        code_for(tp.path)[tp.lineno - 1],
        tp.return_value,
        tp.path,
      )
    end
  end
end