如何存儲和讀取 RubyVM::InstructionSequence？

Question

有沒有辦法將 RubyVM::InstructionSequence 存儲到文件並稍后讀取？

我試過Marshal.dump沒有成功。 我收到以下錯誤：

`dump': no _dump_data is defined for class RubyVM::InstructionSequence (TypeError)

Answer 1

是的，有辦法。

首先，您需要創建可訪問的InstructionSequence load方法，默​​認情況下該方法是禁用的：

require 'fiddle'

class RubyVM::InstructionSequence
  # Retrieve Ruby Core's C-ext `iseq_load' function address
  load_fn_addr  = Fiddle::Handle::DEFAULT['rb_iseq_load']
  # Retrieve `iseq_load' C function representation
  load_fn       = Fiddle::Function.new(load_fn_addr,
                                       [Fiddle::TYPE_VOIDP] * 3,
                                       Fiddle::TYPE_VOIDP)

  # Make `iseq_load' accessible as `load' class method
  define_singleton_method(:load) do |data, parent = nil, opt = nil|
    load_fn.call(Fiddle.dlwrap(data), parent, opt).to_value
  end
end

由於RubyVM::InstructionSequence.load方法可以將已編譯的 VM 指令作為數組加載，因此您可以自由地將其用於（反）序列化目的：

irb> # compile simple ruby program into its instruction sequence
irb> seq = RubyVM::InstructionSequence.new <<-EOS
irb:   p 'Hello, world !'
irb:   EOS
=> <RubyVM::InstructionSequence:<compiled>@<compiled>

irb> # serialize sequence as Array instance representation
irb> data = Marshal.dump seq.to_a
=> "\x04\b[\x13\"-YARVInstructionSequence/SimpleDataFormat … ]"

irb> # de-serialize previously serialized sequence
irb> seq_loaded = Marshal.load data
=> ["YARVInstructionSequence/SimpleDataFormat", 2, 2, 1, { … ]

irb> # load deserialized Array back into instruction sequence
irb> new_iseq = RubyVM::InstructionSequence.load seq_loaded
=> <RubyVM::InstructionSequence:<compiled>@<compiled>>

irb> # execute instruction sequence in current context
irb> new_iseq.eval
"Hello, world !"
=> "Hello, world !"

這就是所有人;)

Answer 2

鑒於該類的方法有限，您可以嘗試的東西也有限。 可能你唯一能做的就是將它的實例保存為一個字符串：

puts RubyVM::InstructionSequence.disasm(proc{puts "foo"})

結果：

== disasm: <RubyVM::InstructionSequence:block in irb_binding@(irb)>=====
== catch table
| catch type: redo   st: 0002 ed: 0009 sp: 0000 cont: 0002
| catch type: next   st: 0002 ed: 0009 sp: 0000 cont: 0009
|------------------------------------------------------------------------
0000 trace            256                                             (   1)
0002 trace            1
0004 putself          
0005 putstring        \"foo\"
0007 opt_send_without_block <callinfo!mid:puts, argc:1, FCALL|ARGS_SIMPLE>
0009 trace            512
0011 leave            

當你想反序列化它時，你需要解析這個字符串。

Answer 3

這很簡單。

iseq = RubyVM::InstructionSequence.compile("a = 1 + 2") # just an example
File.open('iseq.bin', 'wb') { |file| file.write iseq.to_binary }

# later
RubyVM::InstructionSequence.load_from_binary(File.read('iseq.bin')).eval # returns 3