Class: RubyRunJs::ByteCodeExecutor

Inherits:
Object
  • Object
show all
Defined in:
lib/ruby_run_js/bytecode_executor.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ ByteCodeExecutor

Returns a new instance of ByteCodeExecutor.



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# File 'lib/ruby_run_js/bytecode_executor.rb', line 6

def initialize()
  @label2loc = {}
  @codes = []
  @scopes = []
  @func_return_locs = []
end

Instance Attribute Details

#codes ⇒ Object (readonly)

Returns the value of attribute codes.



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# File 'lib/ruby_run_js/bytecode_executor.rb', line 4

def codes
  @codes
end

Instance Method Details

#_run_under_control(ctx, label_start, label_end) ⇒ Object 



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# File 'lib/ruby_run_js/bytecode_executor.rb', line 109

def _run_under_control(ctx, label_start, label_end)

  loc_start = @label2loc[label_start]
  loc_end = @label2loc[label_end]
  loc = loc_start

  entry_scope = @scopes.length
  stack_length = ctx.stack.length

  if @debug
    puts "Stack when enter run_under_control: "
    print_stack(ctx.stack)
  end

  while loc < @codes.length || @codes.length == loc_end
    if loc >= loc_end && @scopes.length == entry_scope
      if loc != loc_end
        raise "run_under_control must exit from label_end"
      end
      if ctx.stack.length - stack_length != 1
        raise "Stack must have exactly one value when run_under_control exits"
      end
      return [0, ctx.stack.pop]
    end

    if @debug
      puts 'Will execute: ' + @codes[loc].to_s
    end

    status = @codes[loc].eval(ctx)

    if @debug
      print_stack(ctx.stack)
    end

    if status != nil
      if status.is_a?(Integer)
        loc = @label2loc[status]
        if @scopes.length == entry_scope
          if loc < loc_start || loc >= loc_end
            if ctx.stack.length - stack_length != 1
              if @debug
                puts "Stack when exit run_under_control: "
                print_stack(ctx.stack)
              end
              raise "Stack must have exactly one value when run_under_control exits"
            end
            return [2, ctx.stack.pop, status]
          end
        end
      elsif status == :Return
        if @scopes.length == entry_scope
          if ctx.stack.length - stack_length != 1
            raise "Stack must have exactly one value when run_under_control exits"
          end
          return [1, ctx.stack.pop]
        end
        return_value = ctx.stack.pop()
        ctx = @scopes.pop()
        @current_ctx = ctx
        ctx.stack.push(return_value)
        loc = @func_return_locs.pop()
      elsif status.length == 2
        @scopes.push(ctx)
        @func_return_locs.push(loc + 1)

        loc = @label2loc[status[1]]
        ctx = status[0]
        @current_ctx = ctx
      end
      next
    end
    loc += 1
  end
  raise 'internal error - unexpected end of code, will crash'
end

#call_js_func(func, this, args) ⇒ Object 



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# File 'lib/ruby_run_js/bytecode_executor.rb', line 186

def call_js_func(func, this, args)
  if func.is_native
    raise "func is native when call_js_func"
  end
  old_scopes = @scopes
  old_return_locs = @func_return_locs

  ctx = func.generate_my_scope(this, args)

  @scopes = [LocalScope.new(nil, nil)]
  @func_return_locs = [@codes.length]

  return_value = run(ctx, @label2loc[func.code], @debug)

  @scopes = old_scopes
  @func_return_locs = old_return_locs

  return_value
end

#compile(bytecodes) ⇒ Object 



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# File 'lib/ruby_run_js/bytecode_executor.rb', line 13

def compile(bytecodes)
  i = 0
  length = bytecodes.length
  while i < length
    code = bytecodes[i]
    if code.is_a?(OPCODES::LABEL)
      @label2loc[code.num] = @codes.length
    else
      @codes.push(code)
    end
    i += 1
  end
end

#print_stack(stack) ⇒ Object 



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# File 'lib/ruby_run_js/bytecode_executor.rb', line 27

def print_stack(stack)
  puts 'Stack after execute :'
  stack.each do |v|
    if v.is_a?(Array)
      puts "[#{v.map(&:to_s).join(',')}]"
    else
      puts v
    end
  end
  puts ''
end

#run(ctx, start_loc = 0, debug = false) ⇒ Object 



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# File 'lib/ruby_run_js/bytecode_executor.rb', line 39

def run(ctx, start_loc = 0, debug = false)
  @debug = debug
  loc = start_loc
  @current_ctx = ctx
  while loc < @codes.length
    if @debug
      puts 'Will execute: ' + @codes[loc].to_s
    end
    status = @codes[loc].eval(ctx)

    if @debug
      print_stack(ctx.stack)
    end
    if status != nil
      if status.is_a?(Integer)
        loc = @label2loc[status]
      elsif status == :Return
        return_value = ctx.stack.pop()
        ctx = @scopes.pop()
        @current_ctx = ctx
        ctx.stack.push(return_value)
        loc = @func_return_locs.pop()
      elsif status.length == 2
        @scopes.push(ctx)
        @func_return_locs.push(loc + 1)

        loc = @label2loc[status[1]]
        ctx = status[0]
        @current_ctx = ctx
      end
      next
    end

    loc += 1
  end

  if ctx.stack.length != 1
   # raise "Inernal Error: There must be exactly one value on
   #        the top of stack when codes run done " 
  end

  ctx.stack.pop
end

#run_under_control(ctx, label_start, label_end) ⇒ status, value

status = 0 : normal status = 1 : return status = 2 : jump out status = 3 : error

Returns:

  • (status, value) 


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# File 'lib/ruby_run_js/bytecode_executor.rb', line 88

def run_under_control(ctx, label_start, label_end)
  old_stack_length = ctx.stack.length
  old_ret_length = @func_return_locs.length
  old_scope_length = @scopes.length

  begin
    return _run_under_control(ctx, label_start, label_end)
  rescue JsException => e
    ctx.stack.pop([ctx.stack.length - old_stack_length, 0].max)
    @func_return_locs.pop([@func_return_locs.length - old_ret_length, 0].max)
    @scopes.pop([@scopes.length - old_scope_length, 0].max)

    return [3, e]
  else
    if old_stack_length != ctx.stack.length
      raise "Stack must be not changed after calling run_under_control"
    end
  end

end