Class: DpStmMap::TransactionLog

Inherits:
Object
  • Object
show all
Defined in:
lib/dp_stm_map/Manager.rb

Instance Method Summary collapse

Constructor Details

#initialize(log_dir) ⇒ TransactionLog

Returns a new instance of TransactionLog.



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# File 'lib/dp_stm_map/Manager.rb', line 190

def initialize log_dir
  @log_dir=log_dir

  FileUtils.mkdir_p(log_dir) unless File.exist?(log_dir)

  unless File.exist?("#{log_dir}/last_id.txt")
    File.open("#{log_dir}/last_id.txt","w") {|f| f.write("0")}
    @last_id=0
  else
    @last_id=File.open("#{log_dir}/last_id.txt","r") {|f| f.read().to_i}
  end

  @mutex=Mutex.new
  @change=ConditionVariable.new
end

Instance Method Details

#add_listener(current_state, &block) ⇒ Object 



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# File 'lib/dp_stm_map/Manager.rb', line 218

def add_listener current_state, &block
  Thread.new do
    begin
      loop do
        arg=@mutex.synchronize do
          until current_state < last_id
            @change.wait(@mutex)
          end
          current_state+=1
          [current_state, read_tx(current_state)]
        end
        yield arg
      end


    rescue => e
      # puts "Error during processing: #{$!}"
      # puts "Backtrace:\n\t#{e.backtrace.join("\n\t")}"
    end
  end
end

#last_id ⇒ Object 



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# File 'lib/dp_stm_map/Manager.rb', line 241

def last_id
  @last_id
end

#read_tx(id) ⇒ Object 



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# File 'lib/dp_stm_map/Manager.rb', line 207

def read_tx id
  JSON::parse(File.open("#{@log_dir}/#{id}.json","r") {|f| f.read})
end

#store_transaction(references_to_change, values_to_add, values_to_remove) ⇒ Object 



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# File 'lib/dp_stm_map/Manager.rb', line 245

def store_transaction references_to_change, values_to_add, values_to_remove
  @mutex.synchronize do
    txid=last_id+1
    write_tx txid, [references_to_change, values_to_add, values_to_remove]
    File.open("#{@log_dir}/last_id.txt","w") {|f| f.write(txid.to_s)}
    @change.broadcast
    @last_id=txid
    txid
  end
end

#write_tx(id, tx) ⇒ Object 



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# File 'lib/dp_stm_map/Manager.rb', line 211

def write_tx id, tx

  File.open("#{@log_dir}/#{id}.json","w") {|f| f.write(tx.to_json)}
end