1 # This file is part of NIT ( http://www.nitlanguage.org ).
3 # Copyright 2014 Alexis Laferrière <alexis.laf@xymus.net>
5 # Licensed under the Apache License, Version 2.0 (the "License");
6 # you may not use this file except in compliance with the License.
7 # You may obtain a copy of the License at
9 # http://www.apache.org/licenses/LICENSE-2.0
11 # Unless required by applicable law or agreed to in writing, software
12 # distributed under the License is distributed on an "AS IS" BASIS,
13 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 # See the License for the specific language governing permissions and
15 # limitations under the License.
17 # Abstract services to serialize Nit objects to different formats
19 # This module declares the `serialize` annotation to mark Nit classes as serializable.
20 # For an introduction to this service, refer to the documentation of the `serialization` group.
21 # This documentation provides more technical information on interesting entitie of this module.
23 # Interesting entities for end users of serializable classes:
25 # * Serialize an instance subclass of `Serializable` with either
26 # `Serializer::serializable` and `Serializable::serialize`.
27 # * Deserialize an object using `Deserializer::deserialize`.
28 # The object type must the be checked with an `assert` or otherwise.
30 # Interesting entities to create custom serializable classes:
32 # * Subclass `Serializable` to declare a class as serializable and to customize
33 # the serialization and deserialization behavior.
34 # * Redefine `Serializable::core_serialize_to` to customize the serialization
35 # of the receiver class.
36 # * Redefine `Deserializer::deserialize_class` to customize the deserialization
37 # of a specific class by name.
39 # Interesting entities for serialization format:
41 # * Subclass `Serializer` and `Deserializer` with custom serices.
42 # * In `Serializer`, `serialize` and `serialize_reference` must be redefined.
43 # * In `Deserializer`; `deserialize`, `deserialize_attribute and
44 # `notify_of_creation` must be redefined.
45 module serialization
is
46 new_annotation auto_serializable
47 new_annotation serialize
48 new_annotation noserialize
49 new_annotation serialize_as
52 intrude import core
::queue
55 # Abstract serialization service to be sub-classed by specialized services.
57 # Entry point method of this service, serialize the `object`
59 # This method, and refinements, should handle `null` and probably
60 # use double dispatch to customize the bahavior per serializable objects.
61 fun serialize
(object
: nullable Serializable) is abstract
63 # The object currently serialized by `serialized`
65 # Can be used by a custom serializer to add domain-specific serialization behavior.
66 protected fun current_object
: nullable Object is abstract
68 # Serialize an object, with full serialization or a simple reference
69 protected fun serialize_reference
(object
: Serializable) is abstract
71 # Serialize an attribute to compose a serializable object
73 # This method should be called from `Serializable::core_serialize_to`.
74 fun serialize_attribute
(name
: String, value
: nullable Object)
76 if not try_to_serialize
(value
) then
77 warn
("argument {name} of type {value.class_name} is not serializable.")
81 # Serialize `value` is possie, i.e. it is `Serializable` or `null`
82 fun try_to_serialize
(value
: nullable Object): Bool
84 if value
isa Serializable then
85 value
.serialize_to_or_delay
(self)
86 else if value
== null then
92 # The method is called when a standard `value` is serialized
94 # The default behavior is to call `value.core_serialize_to(self)` but it
95 # can be redefined by a custom serializer to add domain-specific serialization behavior.
96 fun serialize_core
(value
: Serializable)
98 value
.core_serialize_to
(self)
101 # Warn of problems and potential errors (such as if an attribute
102 # is not serializable)
103 fun warn
(msg
: String) do print
"Serialization warning: {msg}"
106 # Abstract deserialization service
108 # The main service is `deserialize`.
109 abstract class Deserializer
110 # Deserialize and return an object, storing errors in the attribute `errors`
112 # If a `static_type` is given, only subtypes of the `static_type` are accepted.
114 # This method behavior varies according to the implementation engines.
115 fun deserialize
(static_type
: nullable String): nullable Object is abstract
117 # Deserialize the attribute with `name` from the object open for deserialization
119 # The `static_type` restricts what kind of object can be deserialized.
121 # Return the deserialized value or null on error, and set
122 # `deserialize_attribute_missing` to whether the attribute was missing.
124 # Internal method to be implemented by the engines.
125 fun deserialize_attribute
(name
: String, static_type
: nullable String): nullable Object is abstract
127 # Was the attribute queried by the last call to `deserialize_attribute` missing?
128 var deserialize_attribute_missing
= false
130 # Register a newly allocated object (even if not completely built)
132 # Internal method called by objects in creation, to be implemented by the engines.
133 fun notify_of_creation
(new_object
: Object) is abstract
135 # Deserialize the next available object as an instance of `class_name`
137 # Return the deserialized object on success and
138 # record in `errors` if `class_name` is unknown.
140 # This method should be redefined for each custom subclass of `Serializable`.
141 # All refinement should look for a precise `class_name` and call super
142 # on unsupported classes.
143 protected fun deserialize_class
(class_name
: String): nullable Object do
144 if class_name
== "Error" then return new Error.from_deserializer
(self)
145 return deserialize_class_intern
(class_name
)
148 # Generated service to deserialize the next available object as an instance of `class_name`
150 # Refinements to this method will be generated by the serialization phase.
151 # To avoid conflicts, there should not be any other refinements to this method.
152 # You can instead use `deserialize_class`.
153 protected fun deserialize_class_intern
(class_name
: String): nullable Object do
154 errors
.add
new Error("Deserialization Error: Doesn't know how to deserialize class \"{class_name}\
"")
158 # Should `self` keep trying to deserialize an object after an error?
160 # This behavior takes effect after each attribute deserialization with
161 # errors such as a missing attribute or the value is of the wrong type.
162 # If `keep_going`, the attribute will be skipped but the engine will
163 # deserialize the next attribute.
164 # If `not keep_going`, the engine stops deserializing right away.
166 # When at `true`, this may cause the accumulation of a lot of entries in `errors`.
169 var keep_going
: nullable Bool = null is writable
171 # Errors encountered in the last call to `deserialize`
172 var errors
= new Array[Error]
175 # Deserialization error related to an attribute of `receiver`
176 abstract class AttributeError
179 # Parent object of the problematic attribute
182 # Name of the problematic attribute in `receiver`
183 var attribute_name
: String
186 # Invalid dynamic type for a deserialized attribute
187 class AttributeTypeError
190 autoinit receiver
, attribute_name
, attribute
, expected_type
192 # Deserialized object that isn't of the `expected_type`
193 var attribute
: nullable Object
195 # Name of the type expected for `attribute`
196 var expected_type
: String
198 redef var message
is lazy
do
199 var attribute
= attribute
200 var found_type
= if attribute
!= null then attribute
.class_name
else "null"
202 return "Deserialization Error: {
203 }Wrong type on `{receiver.class_name}::{attribute_name}` expected `{expected_type}`, got `{found_type}`"
207 # Missing attribute at deserialization
208 class AttributeMissingError
211 autoinit receiver
, attribute_name
213 redef var message
is lazy
do
214 return "Deserialization Error: Missing attribute `{receiver.class_name}::{attribute_name}`"
218 # Instances of this class can be passed to `Serializer::serialize`
219 interface Serializable
220 # Serialize `self` to `serializer`
222 # This is a shortcut to `Serializer::serialize`.
223 fun serialize_to
(serializer
: Serializer) do serializer
.serialize
(self)
225 # Actual serialization of `self` to `serializer`
227 # This writes the full data of `self` to `serializer`.
229 # This method can be redefined in sub classes and refinements.
230 # It should use `Serializer::serialize_attribute` to to register real or
231 # logical attributes.
233 # Any refinement should have its equivalent refinement of
234 # `Deserializer::deserialize_class` to support this custom deserialization.
235 fun core_serialize_to
(serializer
: Serializer) do end
237 # Accept references or force direct serialization (using `serialize_to`)
239 # The subclass change the default behavior, which will accept references,
240 # to force to always serialize copies of `self`.
241 private fun serialize_to_or_delay
(v
: Serializer) do v
.serialize_reference
(self)
243 # Create an instance of this class from the `deserializer`
245 # This constructor is refined by subclasses to correctly build their instances.
246 init from_deserializer
(deserializer
: Deserializer) is nosuper
do end
249 redef interface Object
250 # Is `self` the same as `other` in a serialization context?
252 # Used to determine if an object has already been serialized.
253 fun is_same_serialized
(other
: nullable Object): Bool do return is_same_instance
(other
)
255 # Hash value use for serialization
257 # Used in combination with `is_same_serialized`. If two objects are the same
258 # in a serialization context, they must have the same `serialization_hash`.
259 fun serialization_hash
: Int do return object_id
262 # Instances of this class are not delayed and instead serialized immediately
263 # This applies mainly to `universal` types
264 interface DirectSerializable
267 redef fun serialize_to_or_delay
(v
) do serialize_to
(v
)
270 redef class Bool super DirectSerializable end
271 redef class Char super DirectSerializable end
272 redef class Int super DirectSerializable end
273 redef class Float super DirectSerializable end
274 redef class CString super DirectSerializable end
275 redef class Text super DirectSerializable end
276 redef class SimpleCollection[E
] super Serializable end
277 redef class Map[K
, V
] super Serializable end
279 redef class Couple[F
, S
]
282 redef init from_deserializer
(v
)
284 v
.notify_of_creation
self
285 var first
= v
.deserialize_attribute
("first")
286 var second
= v
.deserialize_attribute
("second")
290 redef fun core_serialize_to
(v
)
292 v
.serialize_attribute
("first", first
)
293 v
.serialize_attribute
("second", second
)
300 redef init from_deserializer
(v
)
302 v
.notify_of_creation
self
303 var item
= v
.deserialize_attribute
("item")
307 redef fun core_serialize_to
(v
)
309 v
.serialize_attribute
("item", first
)
316 redef init from_deserializer
(v
)
318 v
.notify_of_creation
self
320 var message
= v
.deserialize_attribute
("message")
321 if not message
isa String then message
= ""
324 var cause
= v
.deserialize_attribute
("cause")
325 if cause
isa nullable Error then self.cause
= cause
328 redef fun core_serialize_to
(v
)
330 v
.serialize_attribute
("message", message
)
331 v
.serialize_attribute
("cause", cause
)
336 # core::queue classes
338 redef abstract class ProxyQueue[E
]
340 redef init from_deserializer
(v
)
342 v
.notify_of_creation
self
344 var seq
= v
.deserialize_attribute
("seq", (new GetName[Sequence[E
]]).to_s
)
345 if not seq
isa Sequence[E
] then seq
= new Array[E
]
346 if v
.deserialize_attribute_missing
then
347 v
.errors
.add
new AttributeMissingError(self, "seq")
353 redef fun core_serialize_to
(v
) do v
.serialize_attribute
("seq", seq
)
356 redef class RandQueue[E
]
358 redef init from_deserializer
(v
)
360 v
.notify_of_creation
self
362 var seq
= v
.deserialize_attribute
("seq", (new GetName[SimpleCollection[E
]]).to_s
)
363 if not seq
isa SimpleCollection[E
] then seq
= new Array[E
]
364 if v
.deserialize_attribute_missing
then
365 v
.errors
.add
new AttributeMissingError(self, "seq")
371 redef fun core_serialize_to
(v
) do v
.serialize_attribute
("seq", seq
)
374 redef class MinHeap[E
]
376 redef init from_deserializer
(v
)
378 v
.notify_of_creation
self
380 var items
= v
.deserialize_attribute
("items", (new GetName[SimpleCollection[E
]]).to_s
)
381 if not items
isa Array[E
] then items
= new Array[E
]
382 if v
.deserialize_attribute_missing
then
383 v
.errors
.add
new AttributeMissingError(self, "items")
386 var comparator
= v
.deserialize_attribute
("comparator", "Comparator")
387 if not comparator
isa Comparator then comparator
= default_comparator
388 if v
.deserialize_attribute_missing
then
389 v
.errors
.add
new AttributeMissingError(self, "comparator")
393 self.items
.add_all items
396 redef fun core_serialize_to
(v
)
398 v
.serialize_attribute
("items", items
)
399 v
.serialize_attribute
("comparator", comparator
)