frontend serialization: don't create `core_serialize_to` if it exists

[nit.git] / src / frontend / serialization_phase.nit

# This file is part of NIT ( http://www.nitlanguage.org ).
#
# Copyright 2013 Jean-Philippe Caissy <jpcaissy@piji.ca>
# Copyright 2013 Guillaume Auger <jeho@resist.ca>
# Copyright 2014 Alexis Laferrière <alexis.laf@xymus.net>
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

# Phase generating methods to serialize Nit objects to different formats
module serialization_phase

private import parser_util
import modelize
private import annotation
intrude import literal

redef class ToolContext

        # Apply the annotation `serialize_as`
        var serialization_phase_rename: Phase = new SerializationPhaseRename(self, null)

        # Generate serialization and deserialization methods on `auto_serializable` annotated classes.
        var serialization_phase_pre_model: Phase = new SerializationPhasePreModel(self,
                [serialization_phase_rename])

        # The second phase of the serialization
        var serialization_phase_post_model: Phase = new SerializationPhasePostModel(self,
                [modelize_property_phase, serialization_phase_pre_model])
end

redef class ANode
        # Is this node annotated to be made serializable?
        private fun is_serialize: Bool do return false

        # Is this node annotated to not be made serializable?
        private fun is_noserialize: Bool do return false
end

redef class ADefinition

        redef fun is_serialize do
                return get_annotations("serialize").not_empty or
                        get_annotations("auto_serializable").not_empty
        end

        redef fun is_noserialize do
                return get_annotations("noserialize").not_empty
        end
end

private class SerializationPhaseRename
        super Phase

        redef fun process_annotated_node(node, nat)
        do
                var text = nat.n_atid.n_id.text
                if text != "serialize_as" then return

                if not node isa AAttrPropdef then
                        toolcontext.error(node.location,
                                "Syntax Error: annotation `{text}` applies only to attributes.")
                        return
                end

                # Can't use `arg_as_string` because it needs the literal phase
                var args = nat.n_args
                if args.length != 1 or not args.first isa AStringFormExpr then
                        toolcontext.error(node.location,
                                "Syntax Error: annotation `{text}` expects a single string literal as argument.")
                        return
                end

                var t = args.first.collect_text
                var val = t.substring(1, t.length-2)
                node.serialize_name = val
        end
end

private class SerializationPhasePreModel
        super Phase

        redef fun process_annotated_node(node, nat)
        do
                # Skip if we are not interested
                var text = nat.n_atid.n_id.text
                var serialize = text == "auto_serializable" or text == "serialize"
                var noserialize = text == "noserialize"
                if not (serialize or noserialize) then return

                # Check legality of annotation
                if node isa AModuledecl then
                        if noserialize then toolcontext.error(node.location, "Syntax Error: superfluous use of `{text}`, by default a module is `{text}`")
                        return
                else if not (node isa AStdClassdef or node isa AAttrPropdef) then
                        toolcontext.error(node.location,
                                "Syntax Error: only a class, a module or an attribute can be annotated with `{text}`.")
                        return
                else if serialize and node.is_noserialize then
                        toolcontext.error(node.location,
                                "Syntax Error: an entity cannot be both `{text}` and `noserialize`.")
                        return
                else if node.as(Prod).get_annotations(text).length > 1 then
                        toolcontext.warning(node.location, "useless-{text}",
                                "Warning: duplicated annotation `{text}`.")
                end

                # Check the `serialize` state of the parent
                if not node isa AModuledecl then
                        var up_serialize = false
                        var up: nullable ANode = node
                        while up != null do
                                up = up.parent
                                if up == null then
                                        break
                                else if up.is_serialize then
                                        up_serialize = true
                                        break
                                else if up.is_noserialize then
                                        break
                                end
                        end

                        # Check for useless double declarations
                        if serialize and up_serialize then
                                toolcontext.warning(node.location, "useless-serialize",
                                        "Warning: superfluous use of `{text}`.")
                        else if noserialize and not up_serialize then
                                toolcontext.warning(node.location, "useless-noserialize",
                                        "Warning: superfluous use of `{text}`.")
                        end
                end
        end

        redef fun process_nclassdef(nclassdef)
        do
                if not nclassdef isa AStdClassdef then return

                var serialize_by_default = nclassdef.how_serialize

                if serialize_by_default != null then

                        # Add `super Serializable`
                        var sc = toolcontext.parse_superclass("Serializable")
                        sc.location = nclassdef.location
                        nclassdef.n_propdefs.add sc

                        # Add services
                        var per_attribute = not serialize_by_default
                        generate_serialization_method(nclassdef, per_attribute)
                        generate_deserialization_init(nclassdef)
                end
        end

        redef fun process_nmodule(nmodule)
        do
                # Clear the cache of constructors to review before adding to it
                nmodule.inits_to_retype.clear

                # collect all classes
                var auto_serializable_nclassdefs = nmodule.auto_serializable_nclassdefs
                if not auto_serializable_nclassdefs.is_empty then
                        generate_deserialization_method(nmodule, auto_serializable_nclassdefs)
                end
        end

        # Implement `core_serialize_to` on `nclassdef`
        #
        # Are attributes serialized on demand `per_attribute` with `serialize`?
        # Otherwise they are serialized by default, and we check instead for `noserialize`.
        fun generate_serialization_method(nclassdef: AClassdef, per_attribute: Bool)
        do
                var npropdefs = nclassdef.n_propdefs

                # Do not insert a `core_serialize_to` if it already exists
                for npropdef in npropdefs do
                        if npropdef isa AMethPropdef then
                                var methid = npropdef.n_methid
                                if methid != null and methid.collect_text == "core_serialize_to" then
                                        return
                                end
                        end
                end

                var code = new Array[String]
                code.add "redef fun core_serialize_to(v)"
                code.add "do"
                code.add "      super"

                for attribute in npropdefs do if attribute isa AAttrPropdef then

                        # Is `attribute` to be skipped?
                        if (per_attribute and not attribute.is_serialize) or
                                attribute.is_noserialize then continue

                        code.add "      v.serialize_attribute(\"{attribute.serialize_name}\", {attribute.name})"
                end

                code.add "end"

                # Create method Node and add it to the AST
                npropdefs.push(toolcontext.parse_propdef(code.join("\n")))
        end

        # Add an empty constructor to the automated nclassdef
        #
        # Will be filled by `SerializationPhasePostModel`.
        fun generate_deserialization_init(nclassdef: AClassdef)
        do
                var npropdefs = nclassdef.n_propdefs

                # Do not insert a `from_deserializer` if it already exists
                for npropdef in npropdefs do
                        if npropdef isa AMethPropdef then
                                var methid = npropdef.n_methid
                                if methid != null and methid.collect_text == "from_deserializer" then
                                        return
                                end
                        end
                end

                var code = """
redef init from_deserializer(v: Deserializer) do abort"""

                var npropdef = toolcontext.parse_propdef(code).as(AMethPropdef)
                npropdefs.add npropdef
                nclassdef.parent.as(AModule).inits_to_retype.add npropdef
        end

        # Add an empty `Deserializer::deserialize_class_intern`
        #
        # Will be filled by `SerializationPhasePostModel`.
        fun generate_deserialization_method(nmodule: AModule, nclassdefs: Array[AStdClassdef])
        do
                var code = new Array[String]

                var deserializer_nclassdef = nmodule.deserializer_nclassdef
                var deserializer_npropdef
                if deserializer_nclassdef == null then
                        # create the class
                        code.add "redef class Deserializer"
                        deserializer_npropdef = null
                else
                        deserializer_npropdef = deserializer_nclassdef.deserializer_npropdef
                end

                if deserializer_npropdef == null then
                        # create the property
                        code.add "      redef fun deserialize_class_intern(name) do abort"
                else
                        toolcontext.error(deserializer_npropdef.location, "Error: `Deserializer::deserialize_class_intern` is generated and must not be defined, use `deserialize_class` instead.")
                        return
                end

                if deserializer_nclassdef == null then
                        code.add "end"
                        nmodule.n_classdefs.add toolcontext.parse_classdef(code.join("\n"))
                else
                        deserializer_nclassdef.n_propdefs.add(toolcontext.parse_propdef(code.join("\n")))
                end
        end
end

private class SerializationPhasePostModel
        super Phase

        # Fill the deserialization init `from_deserializer` and `Deserializer.deserialize_class_intern`
        redef fun process_nmodule(nmodule)
        do
                for npropdef in nmodule.inits_to_retype do
                        var nclassdef = npropdef.parent
                        assert nclassdef isa AStdClassdef

                        var serialize_by_default = nclassdef.how_serialize
                        assert serialize_by_default != null

                        var per_attribute = not serialize_by_default
                        fill_deserialization_init(nclassdef, npropdef, per_attribute)
                end

                # collect all classes
                var auto_serializable_nclassdefs = nmodule.auto_serializable_nclassdefs
                if not auto_serializable_nclassdefs.is_empty then
                        fill_deserialization_method(nmodule, auto_serializable_nclassdefs)
                end
        end

        # Fill the constructor to the generated `init_npropdef` of `nclassdef`
        fun fill_deserialization_init(nclassdef: AClassdef, init_npropdef: AMethPropdef, per_attribute: Bool)
        do
                var code = new Array[String]
                code.add """
redef init from_deserializer(v: Deserializer)
do
        super
        v.notify_of_creation self
"""

                for attribute in nclassdef.n_propdefs do
                        if not attribute isa AAttrPropdef then continue

                        # Is `attribute` to be skipped?
                        if (per_attribute and not attribute.is_serialize) or
                                attribute.is_noserialize then continue

                        var mtype = attribute.mtype
                        if mtype == null then continue
                        var type_name = mtype.to_s
                        var name = attribute.name

                        if type_name == "nullable Object" then
                                # Don't type check
                                code.add """
        self.{{{name}}} = v.deserialize_attribute("{{{attribute.serialize_name}}}", "{{{type_name}}}")
"""
                        else
                                code.add """
        var {{{name}}} = v.deserialize_attribute("{{{attribute.serialize_name}}}", "{{{type_name}}}")
        if v.deserialize_attribute_missing then
"""
                                # What to do when an attribute is missing?
                                if attribute.has_value then
                                        # Leave it to the default value
                                else if mtype isa MNullableType then
                                        code.add """
                self.{{{name}}} = null"""
                                else code.add """
                v.errors.add new Error("Deserialization Error: attribute `{class_name}::{{{name}}}` missing from JSON object")"""

                                code.add """
        else if not {{{name}}} isa {{{type_name}}} then
                v.errors.add new AttributeTypeError(self, "{{{attribute.serialize_name}}}", {{{name}}}, "{{{type_name}}}")
                if v.keep_going == false then return
        else
                self.{{{name}}} = {{{name}}}
        end
"""
                        end
                end

                code.add "end"

                # Replace the body of the constructor
                var npropdef = toolcontext.parse_propdef(code.join("\n")).as(AMethPropdef)
                init_npropdef.n_block = npropdef.n_block

                # Run the literal phase on the generated code
                var v = new LiteralVisitor(toolcontext)
                v.enter_visit(npropdef.n_block)
        end

        # Fill the abstract serialization service
        fun fill_deserialization_method(nmodule: AModule, nclassdefs: Array[AStdClassdef])
        do
                var deserializer_nclassdef = nmodule.deserializer_nclassdef
                if deserializer_nclassdef == null then return
                var deserializer_npropdef = deserializer_nclassdef.deserializer_npropdef
                if deserializer_npropdef == null then return

                # Collect local types expected to be deserialized
                var types_to_deserialize = new Set[String]

                ## Local serializable standard class without parameters
                for nclassdef in nclassdefs do
                        var mclass = nclassdef.mclass
                        if mclass == null then continue

                        if mclass.arity == 0 and mclass.kind == concrete_kind then
                                types_to_deserialize.add mclass.name
                        end
                end

                ## Static parametized types on serializable attributes
                for nclassdef in nmodule.n_classdefs do
                        if not nclassdef isa AStdClassdef then continue

                        for attribute in nclassdef.n_propdefs do
                                if not attribute isa AAttrPropdef then continue

                                var serialize_by_default = nclassdef.how_serialize
                                if serialize_by_default == null then continue
                                var per_attribute = not serialize_by_default

                                # Is `attribute` to be skipped?
                                if (per_attribute and not attribute.is_serialize) or
                                        attribute.is_noserialize then continue

                                var mtype = attribute.mtype
                                if mtype == null then continue
                                if mtype isa MNullableType then mtype = mtype.mtype

                                if mtype isa MClassType and mtype.mclass.arity > 0 and
                                   mtype.mclass.kind == concrete_kind and not mtype.need_anchor then

                                        # Check is a `Serializable`
                                        var mmodule = nmodule.mmodule
                                        if mmodule == null then continue

                                        var greaters = mtype.mclass.in_hierarchy(mmodule).greaters
                                        var is_serializable = false
                                        for sup in greaters do if sup.name == "Serializable" then
                                                is_serializable = true
                                                break
                                        end

                                        if is_serializable then types_to_deserialize.add mtype.to_s
                                end
                        end
                end

                # Build implementation code
                var code = new Array[String]
                code.add "redef fun deserialize_class_intern(name)"
                code.add "do"

                for name in types_to_deserialize do
                        code.add "      if name == \"{name}\" then return new {name}.from_deserializer(self)"
                end

                code.add "      return super"
                code.add "end"

                # Replace the body of the constructor
                var npropdef = toolcontext.parse_propdef(code.join("\n")).as(AMethPropdef)
                deserializer_npropdef.n_block = npropdef.n_block

                # Run the literal phase on the generated code
                var v = new LiteralVisitor(toolcontext)
                v.enter_visit(npropdef.n_block)
        end
end

redef class AAttrPropdef
        private fun name: String do return n_id2.text

        # Name of this attribute in the serialized format
        private var serialize_name: String = name is lazy
end

redef class AType
        private fun type_name: String
        do
                var name = n_qid.n_id.text

                if n_kwnullable != null then name = "nullable {name}"

                var types = n_types
                if not types.is_empty then
                        var params = new Array[String]
                        for t in types do params.add(t.type_name)
                        return "{name}[{params.join(", ")}]"
                else return name
        end
end

redef class AModule
        private fun deserializer_nclassdef: nullable AStdClassdef
        do
                for nclassdef in n_classdefs do
                        if not nclassdef isa AStdClassdef then continue
                        var n_qid = nclassdef.n_qid
                        if n_qid != null and n_qid.n_id.text == "Deserializer" then return nclassdef
                end

                return null
        end

        private var inits_to_retype = new Array[AMethPropdef]

        redef fun is_serialize
        do
                var n_moduledecl = n_moduledecl
                return n_moduledecl != null and n_moduledecl.is_serialize
        end

        # `AStdClassdef` marked as serializable, itself or one of theur attribute
        private var auto_serializable_nclassdefs: Array[AStdClassdef] is lazy do
                var array = new Array[AStdClassdef]
                for nclassdef in n_classdefs do
                        if nclassdef isa AStdClassdef and nclassdef.how_serialize != null then
                                array.add nclassdef
                        end
                end
                return array
        end
end

redef class AStdClassdef
        private fun deserializer_npropdef: nullable AMethPropdef
        do
                for npropdef in n_propdefs do if npropdef isa AMethPropdef then
                        var id = npropdef.n_methid
                        if id isa AIdMethid and id.n_id.text == "deserialize_class_intern" then
                                return npropdef
                        end
                end

                return null
        end

        # Is this classed marked `serialize`? in part or fully?
        #
        # This method returns 3 possible values:
        # * `null`, this class is not to be serialized.
        # * `true`, the attributes of this class are to be serialized by default.
        # * `false`, the attributes of this class are to be serialized on demand only.
        fun how_serialize: nullable Bool
        do
                # Is there a declaration on the classdef or the module?
                var serialize = is_serialize

                if not serialize and not is_noserialize then
                        # Is the module marked serialize?
                        serialize = parent.as(AModule).is_serialize
                end

                if serialize then return true

                if not serialize then
                        # Is there an attribute marked serialize?
                        for npropdef in n_propdefs do
                                if npropdef.is_serialize then
                                        return false
                                end
                        end
                end

                return null
        end
end