Class: Z3Solver

Inherits:
Object
  • Object
show all
Defined in:
lib/solver-lib.rb

Instance Method Summary collapse

Constructor Details

#initialize(progress, z3path) ⇒ Z3Solver

Returns a new instance of Z3Solver.



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# File 'lib/solver-lib.rb', line 140

def initialize(progress, z3path)
  z3version = `#{z3path} --version`.chomp()
  if $?.exitstatus == 0 then
    progress.print_line "INFO: Using #{z3version} found in z3path=#{z3path}"
    @z3in, @z3outAndErr, @z3thr = Open3.popen2e(z3path, '-in', '-smt2')
    Process.detach(@z3thr.pid)
  else
    progress.print_line "WARN: could not find z3 in z3path=#{z3path.inspect}"
    `which z3`
    if $?.exitstatus == 0 then
      z3version = `z3 --version`.chomp()
      progress.print_line "However, #{z3version} is availlable on the PATH. Using this one."
      @z3in, @z3outAndErr, @z3thr = Open3.popen2e('z3', '-in', '-smt2')
      Process.detach(@z3thr.pid)
    else
      raise RuntimeError.new("ERROR: unable to find Z3. Exiting! (Please provide its location in the config file using the key :z3path)")
    end
  end
  @z3in.sync = true

  @sessionIdCounter = 0
end

Instance Method Details

#check_type(type, value, xpath) ⇒ Object 



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# File 'lib/solver-lib.rb', line 373

def check_type(type, value, xpath)
  if type == "String" then
    unless value =~ /\".*\"/ then
      raise RuntimeError.new("inconsistent model value: model value for #{xpath} should be a String, but was #{value}.")
    end
  elsif type == "Bool"
    unless value == "true" or value == "false" then
      raise RuntimeError.new("inconsistent model value for #{xpath} should be a Bool, but was #{value.inspect}.")
    end
  elsif type == "Int"
    unless value =~ /\d+/ then
      raise RuntimeError.new("inconsistent model value: model value for #{xpath} should be a Int, but was #{value}.")
    end
  else
    raise RuntimeError.new("encountered unknown solver type: type of solver-var for #{xpath} is #{info[:type]}.")
  end
end

#close ⇒ Object 



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# File 'lib/solver-lib.rb', line 163

def close()
  @z3in.close()
  @z3outAndErr.close()
  Thread.kill(@z3thr)
end

#convert_solver_value(type, datatype, value, xpath) ⇒ Object 



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# File 'lib/solver-lib.rb', line 391

def convert_solver_value(type, datatype, value, xpath)
  check_type(type, value, xpath)
  if datatype == :date then
    return (Time.at(0).to_date + Integer(value)).to_s
  elsif datatype == :timestamp then
    return Time.at(Integer(value)).to_s
  else
    return value
  end
end

#display_assertion(assertion, solver) ⇒ Object 



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# File 'lib/solver-lib.rb', line 199

def display_assertion(assertion, solver)
  if assertion =~ /validation_rule_(.*)_instance_(.*)/ then
    return "Validation rule #{$1} of structure #{$2.gsub("_", "/")}"
  else
    info = solver.getAssociationForAssertionID(assertion)
    if info then
      if info[:assertion_type] == :doc_field_filled then
        return "Field #{info[:xpath]} contains value #{info[:value].inspect} in document"
      elsif info[:assertion_type] == :doc_field_empty then
        return "Field #{info[:xpath]} is empty in document"
      elsif info[:assertion_type] == :doc_structure_exists then
        return "Structure #{info[:xpath]} exists in document"
      elsif info[:assertion_type] == :doc_structure_not_exists then
        return "Structure #{info[:xpath]} does not exist in document"
      elsif info[:assertion_type] == :constraint then
        if info[:constraint_type] == :min then
          return "Field #{info[:xpath]} has a minimum value of #{info[:value]}."
        elsif info[:constraint_type] == :max then
          return "Field #{info[:xpath]} has a maximum value of #{info[:value]}."
        elsif info[:constraint_type] == :required then
          return "Field #{info[:xpath]} is required."
        else
          p info
          raise RuntimeError.new("encountered unknown :constraint_type #{info[:constraint_type].inspect} for assertionID #{assertion.inspect}")
        end
      else
        raise RuntimeError.new("encountered unknown :assertion_type #{info[:assertion_type].inspect} for assertionID #{assertion.inspect}")
      end
    else
      return assertion
    end
  end
end

#foreach_field_in_model_str(str, solver, const_info, &block) ⇒ Object 



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# File 'lib/solver-lib.rb', line 402

def foreach_field_in_model_str(str, solver, const_info, &block)
  unless str =~ /^\((.*)\)$/m
    raise RuntimeError.new("could not parse model: #{str.inspect}")
  end
  str = $1

  str.split("\n").each do |line|
    unless line =~ /\(([^\ ]*)\ (.*)\)/
      raise RuntimeError.new("could not parse model line: #{line.inspect}")
    end
    varname = $1
    value = $2
    if value =~ /\(-\ (\d+)\)/ then
      simplified = "-#{$1}"
      value = simplified
    end
    info = const_info[varname]

    block.call(varname, value, info)
  end

  return nil
end

#handleSolverError(progress, solver, options, result) ⇒ Object

Raises:

  • (RuntimeError) 


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# File 'lib/solver-lib.rb', line 426

def handleSolverError(progress, solver, options, result)
  solver.writeProtocolToFile(progress, options[:solverLog])
  raise RuntimeError.new("Solver Error: Solver returned '#{result}', for more information see #{options[:solverLog]}")
end

#parse_unsat_core(solver, unsat_core) ⇒ Object 



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# File 'lib/solver-lib.rb', line 233

def parse_unsat_core(solver, unsat_core)
  unsat_core = unsat_core.chomp
  # TODO: implement
  unless unsat_core =~ /\((.*)\)/ then
    raise RuntimeError.new("could not parse unsat core: #{unsat_core.inspect}")
  end
  list = $1.split(" ")

  result = "EXPLANATION:\n"
  result += "The following values\n"

  list.filter{|a| a.start_with?("doc-")}.each do |assertion|
    result += "- #{display_assertion(assertion, solver)} (#{assertion})\n"
  end
  result += "\nviolate the following constraints\n"
  list.filter{|a| !a.start_with?("doc-")}.each do |assertion|
    result += "- #{display_assertion(assertion, solver)} (#{assertion})\n"
  end
  return result
end

#query(progress, options, &block) ⇒ Object 



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# File 'lib/solver-lib.rb', line 169

def query(progress, options, &block)
  unless options[:solverLog]
    raise RuntimeError.new("No solverLog specified, but the option :solverLog is required!")
  end
  progress.print_line("calling solver (solver-log is written to #{options[:solverLog]})")
  solver = SolverSession.new(@z3in, @z3outAndErr, options[:solverLog])

  block.call(solver)

  solver.to_solver(progress, "(check-sat)")
  result = solver.from_solver(progress)
  explanation = true
  if result.chomp == "sat"
      # model is not contradictory -> continue
  elsif result.chomp == "unsat"
      # model is contradictory -> add a message

      solver.to_solver(progress, "(get-unsat-core)")
      unsat_core = solver.from_solver(progress)
      explanation = parse_unsat_core(solver, unsat_core)
  else
    handleSolverError(progress, solver, options, result)
  end

  solver.to_solver(progress, "(reset)")
  solver.to_solver(progress, "(set-logic ALL)") 
  solver.to_solver(progress, "(set-option :produce-unsat-cores true)") 
  return explanation
end

#query_model(progress, options, &block) ⇒ Object

main entry point!



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# File 'lib/solver-lib.rb', line 255

def query_model(progress, options, &block)
  unless options[:solverLog]
    raise RuntimeError.new("No solverLog specified, but the option :solverLog is required!")
  end
  progress.print_line("calling solver (solver-log is written to #{options[:solverLog]})")
  solver = SolverSession.new(@z3in, @z3outAndErr, options[:solverLog])

  block.call(solver)
  
  solver.to_solver(progress, "(check-sat)")
  result = solver.from_solver(progress)
  if result.chomp == "sat"
      # model is not contradictory -> extract model
      const_list = []
      const_info = {}
      solver.for_each_const do |name, info|
        const_list << name
        const_info[name] = info
      end
      solver.to_solver(progress, "(get-value (#{const_list.join(" ")}))")
      model_str = solver.read_multiline_from_solver()
      model = {}
      foreach_field_in_model_str(model_str, solver, const_info) do |varname, value, info|
        unless info then
          progress.print_line "WARN: no info availlable for varname=#{varname.inspect}, value=#{value.inspect}"
        end
        xpath = info[:xpath]
        if model.has_key?(xpath) then
          if varname.end_with?("-filled") then
            unless model[xpath][:type] == :field then
              raise RuntimeError.new("inconsistent model: xpath #{xpath} should be a field, not a #{model[xpath][:type]}.")
            end
            unless value == "true" or value == "false" then
              raise RuntimeError.new("inconsistent model value filled-value of #{xpath} should be a Bool, but was #{value.inspect}.")
            end
            if value == "true" then
              model[xpath][:filled] = true
            else
              model[xpath][:filled] = false
            end
          elsif varname.end_with?("-value") then
            unless model[xpath][:type] == :field || model[xpath][:type] == :list then
              raise RuntimeError.new("inconsistent model: xpath #{xpath} should be a field or a list, not a #{model[xpath][:type]}.")
            end
            if model[xpath][:type] == :field then
              model[xpath][:value] = convert_solver_value(info[:type], info[:datatype], value, xpath)
            elsif model[xpath][:type] == :list then
              unless varname =~ /-index-(\d+)-value$/
                raise RuntimeError.new("inconsistent model: xpath #{xpath} is a list value and hence its varname should end like -index-X-value, not #{varname.inspect}.")
              end
              index = Integer($1)
              model[xpath][:xpath_element] = info[:xpath_element]
              if model[xpath].has_key?(:value) then
                val = convert_solver_value(info[:type], info[:datatype], value, xpath)
                model[xpath][:value].insert(index, val)
              else
                val = convert_solver_value(info[:type], info[:datatype], value, xpath)
                model[xpath][:value] = [val]
              end
            end
          elsif varname.end_with?("-size") then
            unless model[xpath][:type] == :list || model[xpath][:type] == :field then
              raise RuntimeError.new("inconsistent model: xpath #{xpath} should be a list or a field, not a #{model[xpath][:type]}.")
            end
            if model[xpath][:type] == :field then
              model[xpath][:type] = :list
            end
            model[xpath][:size] = Integer(value)
          elsif varname.start_with?("struct-") && varname.end_with?("-exists") then
            unless model[xpath][:type] == :struct then
              raise RuntimeError.new("inconsistent model: xpath #{xpath} should be a struct, not a #{model[xpath][:type]}.")
            end
            model[xpath][:exists] = value
          end
        else
          if varname.end_with?("-filled") then
            unless value == "true" or value == "false" then
              raise RuntimeError.new("inconsistent model value filled-value of #{xpath} should be a Bool, but was #{value.inspect}.")
            end
            if value == "true" then
              model[xpath] = { :type => :field, :filled => true }
            else
              model[xpath] = { :type => :field, :filled => false }
            end
          elsif varname.end_with?("-value") then
            check_type(info[:type], value, xpath)
            model[xpath] = {  :type => :field, :value => value }
          elsif varname.start_with?("struct-") && varname.end_with?("-exists") then
            unless value == "true" or value == "false" then
              raise RuntimeError.new("inconsistent model value exists-value of struct #{xpath} should be a Bool, but was #{value.inspect}.")
            end
            model[xpath] = { :type => :struct, :exists => value }
          elsif varname.end_with?("-size") then
            model[xpath] = { :type => :list, :size => value }
          end
        end
      end
      return model
  elsif result.chomp == "unsat"
      # model is contradictory -> add a message

      solver.to_solver(progress, "(get-unsat-core)")
      unsat_core = solver.from_solver(progress)
      solver.writeProtocolToFile(progress, options[:solverLog])
      progress.print_line "Solver reported a contradiction! please see #{options[:solverLog]} for further information."
      return nil
  else
    handleSolverError(progress, solver, options, result)
  end

  messages = []
  solver.to_solver "(reset)"
  solver.to_solver "(set-logic ALL)"
  solver.to_solver "(set-option :produce-unsat-cores true)"

  return messages
end