Class: Oso::Polar::Host

Inherits:
Object
  • Object
show all
Defined in:
lib/oso/polar/host.rb

Overview

Translate between Polar and the host language (Ruby).

Constant Summary collapse

DEFAULT_COMBINE_QUERY = 
proc { raise 'implement combine_query to use data filtering' }
DEFAULT_BUILD_QUERY = 
proc { raise 'implement build_query to use data filtering' }
DEFAULT_EXEC_QUERY = 
proc { raise 'implement exec_query to use data filtering' }
OPS = 
{
  'Lt' => :<,
  'Gt' => :>,
  'Eq' => :==,
  'Geq' => :>=,
  'Leq' => :<=,
  'Neq' => :!=
}.freeze

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(ffi_polar) ⇒ Host

Returns a new instance of Host.



78
79
80
81
82
83
84
85
86
 
# File 'lib/oso/polar/host.rb', line 78

def initialize(ffi_polar)
  @ffi_polar = ffi_polar
  @types = {}
  @instances = {}
  @accept_expression = false
  @combine_query = DEFAULT_COMBINE_QUERY
  @build_query = DEFAULT_BUILD_QUERY
  @exec_query = DEFAULT_EXEC_QUERY
end

Instance Attribute Details

#accept_expression=(value) ⇒ Object

Sets the attribute accept_expression

Parameters:

  • value —

    the value to set the attribute accept_expression to.



71
72
73
 
# File 'lib/oso/polar/host.rb', line 71

def accept_expression=(value)
  @accept_expression = value
end

#adapter ⇒ Object

Returns the value of attribute adapter.



72
73
74
 
# File 'lib/oso/polar/host.rb', line 72

def adapter
  @adapter
end

#build_query ⇒ Object

Returns the value of attribute build_query.



72
73
74
 
# File 'lib/oso/polar/host.rb', line 72

def build_query
  @build_query
end

#combine_query ⇒ Object

Returns the value of attribute combine_query.



72
73
74
 
# File 'lib/oso/polar/host.rb', line 72

def combine_query
  @combine_query
end

#exec_query ⇒ Object

Returns the value of attribute exec_query.



72
73
74
 
# File 'lib/oso/polar/host.rb', line 72

def exec_query
  @exec_query
end

#types ⇒ Hash<String, UserType> (readonly)

Returns:



58
59
60
 
# File 'lib/oso/polar/host.rb', line 58

def types
  @types
end

Instance Method Details

#cache_class(cls, name:, fields:, build_query:, combine_query:, exec_query:) ⇒ String

Store a Ruby class in the #types cache.

under a previously-registered name.

Parameters:

  • cls (Class) —

    the class to cache.

  • name (String) —

    the name to cache the class as.

Returns:

  • (String) —

    the name the class is cached as.

Raises:



113
114
115
116
117
118
119
120
121
122
123
124
125
126
 
# File 'lib/oso/polar/host.rb', line 113

def cache_class(cls, name:, fields:, build_query:, combine_query:, exec_query:) # rubocop:disable Metrics/ParameterLists, Metrics/MethodLength
  raise DuplicateClassAliasError.new name: name, old: get_class(name), new: cls if types.key? name

  types[name] = types[cls] = UserType.new(
    name: name,
    klass: PolarClass.new(cls),
    id: cache_instance(cls),
    fields: fields || {},
    combine_query: combine_query || self.combine_query,
    exec_query: exec_query || self.exec_query,
    build_query: build_query || self.build_query
  )
  name
end

#cache_instance(instance, id: nil) ⇒ Integer

Cache a Ruby instance in the #instances cache, fetching a new id if one isn't provided.

Parameters:

  • instance (Object)
  • id (Integer) (defaults to: nil) —

    the instance ID. Generated via FFI if not provided.

Returns:

  • (Integer) —

    the instance ID.



171
172
173
174
175
176
177
 
# File 'lib/oso/polar/host.rb', line 171

def cache_instance(instance, id: nil)
  id = ffi_polar.new_id if id.nil?
  # Save the instance as a PolarClass if it is a non-anonymous class
  instance = PolarClass.new(instance) if instance.is_a?(Class)
  instances[id] = instance
  id
end

#enrich_message(msg) ⇒ Object 



412
413
414
415
416
 
# File 'lib/oso/polar/host.rb', line 412

def enrich_message(msg)
  msg.gsub(/\^\{id: ([0-9]+)\}/) do
    get_instance(Regexp.last_match[1].to_i).to_s
  end
end

#get_class(name) ⇒ Class

Fetch a Ruby class from the #types cache.

Parameters:

  • name (String)

Returns:

  • (Class)

Raises:



99
100
101
102
103
104
 
# File 'lib/oso/polar/host.rb', line 99

def get_class(name)
  typ = types[name]
  raise UnregisteredClassError, name if typ.nil?

  typ.klass.get
end

#get_instance(id) ⇒ Object

Fetch a Ruby instance from the #instances cache.

Parameters:

  • id (Integer)

Returns:

  • (Object)

Raises:



156
157
158
159
160
161
162
163
 
# File 'lib/oso/polar/host.rb', line 156

def get_instance(id)
  raise UnregisteredInstanceError, id unless instance? id

  instance = instances[id]
  return instance.get if instance.is_a? PolarClass

  instance
end

#initialize_copy(other) ⇒ Object 



88
89
90
91
92
 
# File 'lib/oso/polar/host.rb', line 88

def initialize_copy(other)
  @ffi_polar = other.ffi_polar
  @types = other.types.dup
  @instances = other.instances.dup
end

#instance?(id) ⇒ Boolean

Check if an instance exists in the #instances cache.

Parameters:

  • id (Integer)

Returns:

  • (Boolean) 


142
143
144
145
146
147
148
149
 
# File 'lib/oso/polar/host.rb', line 142

def instance?(id)
  case id
  when Integer
    instances.key? id
  else
    instances.value? id
  end
end

#isa?(instance, class_tag:) ⇒ Boolean

Check if instance is an instance of class.

Parameters:

  • instance (Hash<String, Object>)
  • class_tag (String)

Returns:

  • (Boolean) 


248
249
250
251
252
 
# File 'lib/oso/polar/host.rb', line 248

def isa?(instance, class_tag:)
  instance = to_ruby(instance)
  cls = get_class(class_tag)
  instance.is_a? cls
end

#make_instance(cls_name, args:, kwargs:, id:) ⇒ Integer

Construct and cache a Ruby instance.

Parameters:

  • cls_name (String) —

    name of the instance's class.

  • args (Array<Object>) —

    positional args to the constructor.

  • kwargs (Hash<String, Object>) —

    keyword args to the constructor.

  • id (Integer) —

    the instance ID.

Returns:

  • (Integer) —

    the instance ID.

Raises:



187
188
189
190
191
192
193
194
195
196
 
# File 'lib/oso/polar/host.rb', line 187

def make_instance(cls_name, args:, kwargs:, id:)
  instance = if kwargs.empty? # This check is for Ruby < 2.7.
               get_class(cls_name).__send__(:new, *args)
             else
               get_class(cls_name).__send__(:new, *args, **kwargs)
             end
  cache_instance(instance, id: id)
rescue StandardError => e
  raise PolarRuntimeError, "Error constructing instance of #{cls_name}: #{e}"
end

#operator(operation, args) ⇒ Boolean

Compare two values

Parameters:

  • operation (String) —

    operation to perform.

  • args (Array<Object>) —

    left and right args to operation.

Returns:

  • (Boolean)

Raises:



213
214
215
216
217
218
219
220
221
222
223
 
# File 'lib/oso/polar/host.rb', line 213

def operator(operation, args)
  left, right = args
  op = OPS[operation]
  raise PolarRuntimeError, "Unsupported external operation '#{left.class} #{operation} #{right.class}'" if op.nil?

  begin
    left.__send__ op, right
  rescue StandardError
    raise PolarRuntimeError, "External operation '#{left.class} #{operation} #{right.class}' failed."
  end
end

#register_mros ⇒ Object

rubocop:disable Metrics/AbcSize



128
129
130
131
132
133
134
135
136
 
# File 'lib/oso/polar/host.rb', line 128

def register_mros # rubocop:disable Metrics/AbcSize
  types.values.uniq.each do |typ|
    mro = []
    typ.klass.get.ancestors.each do |a|
      mro.push(types[a].id) if types.key?(a)
    end
    ffi_polar.register_mro(typ.name, mro)
  end
end

#serialize_types ⇒ Object

rubocop:disable Metrics/AbcSize, Metrics/MethodLength



254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
 
# File 'lib/oso/polar/host.rb', line 254

def serialize_types # rubocop:disable Metrics/AbcSize, Metrics/MethodLength
  polar_types = {}
  types.values.uniq.each do |typ|
    tag = typ.name
    fields = typ.fields
    field_types = {}
    fields.each do |k, v|
      field_types[k] =
        if v.is_a? ::Oso::Polar::DataFiltering::Relation
          {
            'Relation' => {
              'kind' => v.kind,
              'other_class_tag' => v.other_type,
              'my_field' => v.my_field,
              'other_field' => v.other_field
            }
          }
        else
          { 'Base' => { 'class_tag' => types[v].name } }
        end
    end
    polar_types[tag] = field_types
  end
  polar_types
end

#subclass?(left_tag:, right_tag:) ⇒ Boolean

Returns:

  • (Boolean) 


239
240
241
 
# File 'lib/oso/polar/host.rb', line 239

def subclass?(left_tag:, right_tag:)
  get_class(left_tag) <= get_class(right_tag)
end

#subspecializer?(instance_id, left_tag:, right_tag:) ⇒ Boolean

Check if the left class is more specific than the right class with respect to the given instance.

Parameters:

  • instance_id (Integer)
  • left_tag (String)
  • right_tag (String)

Returns:

  • (Boolean) 


232
233
234
235
236
237
 
# File 'lib/oso/polar/host.rb', line 232

def subspecializer?(instance_id, left_tag:, right_tag:)
  mro = get_instance(instance_id).class.ancestors
  left_index = mro.index(get_class(left_tag))
  right_index = mro.index(get_class(right_tag))
  left_index && right_index && left_index < right_index
end

#to_polar(value) ⇒ Hash<String, Object>

Turn a Ruby value into a Polar term that's ready to be sent across the FFI boundary.

Parameters:

  • value (Object)

Returns:

  • (Hash<String, Object>) 


285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
 
# File 'lib/oso/polar/host.rb', line 285

def to_polar(value) # rubocop:disable Metrics/AbcSize, Metrics/CyclomaticComplexity, Metrics/MethodLength, Metrics/PerceivedComplexity
  value = case true # rubocop:disable Lint/LiteralAsCondition
          when value.instance_of?(TrueClass) || value.instance_of?(FalseClass)
            { 'Boolean' => value }
          when value.instance_of?(Integer)
            { 'Number' => { 'Integer' => value } }
          when value.instance_of?(Float)
            if value == Float::INFINITY
              value = 'Infinity'
            elsif value == -Float::INFINITY
              value = '-Infinity'
            elsif value.nan?
              value = 'NaN'
            end
            { 'Number' => { 'Float' => value } }
          when value.instance_of?(String)
            { 'String' => value }
          when value.instance_of?(Array)
            { 'List' => value.map { |el| to_polar(el) } }
          when value.instance_of?(Hash)
            { 'Dictionary' => { 'fields' => value.transform_values { |v| to_polar(v) } } }
          when value.instance_of?(Predicate)
            { 'Call' => { 'name' => value.name, 'args' => value.args.map { |el| to_polar(el) } } }
          when value.instance_of?(Variable)
            # This is supported so that we can query for unbound variables
            { 'Variable' => value.name }
          when value.instance_of?(Expression)
            { 'Expression' => { 'operator' => value.operator, 'args' => value.args.map { |el| to_polar(el) } } }
          when value.instance_of?(Pattern)
            dict = to_polar(value.fields)['value']
            if value.tag.nil?
              { 'Pattern' => dict }
            else
              { 'Pattern' => { 'Instance' => { 'tag' => value.tag, 'fields' => dict['Dictionary'] } } }
            end
          else
            instance_id = nil
            class_id = nil
            class_repr = nil
            # id=class_id,

            # pass `class_id` & `class_repr` for registered types
            if value.is_a?(Class) && types.key?(value)
              instance_id = class_id = types[value].id
            elsif types.key?(value.class)
              class_id = types[value.class].id
              class_repr = types[value.class].name
            end

            {
              'ExternalInstance' => {
                'instance_id' => cache_instance(value, id: instance_id),
                'repr' => nil,
                'class_repr' => class_repr,
                'class_id' => class_id
              }
            }
          end
  { 'value' => value }
end

#to_ruby(data) ⇒ Object

Turn a Polar term passed across the FFI boundary into a Ruby value.

Parameters:

  • data (Hash<String, Object>)

Options Hash (data):

  • :id (Integer)
  • :offset (Integer) —

    Character offset of the term in its source string.

  • :value (Hash<String, Object>)

Returns:

  • (Object)

Raises:



354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
 
# File 'lib/oso/polar/host.rb', line 354

def to_ruby(data) # rubocop:disable Metrics/AbcSize, Metrics/CyclomaticComplexity, Metrics/MethodLength, Metrics/PerceivedComplexity
  tag, value = data['value'].first
  case tag
  when 'String', 'Boolean'
    value
  when 'Number'
    num = value.values.first
    case value.keys.first
    when 'Float'
      case num
      when 'Infinity'
        Float::INFINITY
      when '-Infinity'
        -Float::INFINITY
      when 'NaN'
        Float::NAN
      else
        unless value['Float'].is_a? Float # rubocop:disable Metrics/BlockNesting
          raise PolarRuntimeError, "Expected a floating point number, got \"#{value['Float']}\""
        end

        num
      end
    else
      num
    end
  when 'List'
    value.map { |el| to_ruby(el) }
  when 'Dictionary'
    value['fields'].transform_values { |v| to_ruby(v) }
  when 'ExternalInstance'
    get_instance(value['instance_id'])
  when 'Call'
    Predicate.new(value['name'], args: value['args'].map { |a| to_ruby(a) })
  when 'Variable'
    Variable.new(value)
  when 'Expression'
    raise UnexpectedPolarTypeError, tag unless accept_expression

    args = value['args'].map { |a| to_ruby(a) }
    Expression.new(value['operator'], args)
  when 'Pattern'
    case value.keys.first
    when 'Instance'
      tag = value.values.first['tag']
      fields = value.values.first['fields']['fields'].transform_values { |v| to_ruby(v) }
      Pattern.new(tag, fields)
    when 'Dictionary'
      fields = value.values.first['fields'].transform_values { |v| to_ruby(v) }
      Pattern.new(nil, fields)
    else
      raise UnexpectedPolarTypeError, "#{value.keys.first} variant of Pattern"
    end
  else
    raise UnexpectedPolarTypeError, tag
  end
end