frontend serialization: do not generate from_deserializer if it exists locally

[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

redef class ToolContext
        # Generate serialization and deserialization methods on `auto_serializable` annotated classes.
        var serialization_phase_pre_model: Phase = new SerializationPhasePreModel(self, null)

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

        private fun place_holder_type_name: String do return "PlaceHolderTypeWhichShouldNotExist"
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

        private fun accept_precise_type_visitor(v: PreciseTypeVisitor) do visit_all(v)
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 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
                        loop
                                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, per_attribute)
                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 = new Array[AStdClassdef]
                for nclassdef in nmodule.n_classdefs do
                        if nclassdef isa AStdClassdef and nclassdef.how_serialize != null then
                                auto_serializable_nclassdefs.add nclassdef
                        end
                end

                if not auto_serializable_nclassdefs.is_empty then
                        generate_deserialization_method(nmodule, auto_serializable_nclassdefs)
                end
        end

        fun generate_serialization_method(nclassdef: AClassdef, per_attribute: Bool)
        do
                var npropdefs = nclassdef.n_propdefs

                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

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

                code.add "end"

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

        # Add a constructor to the automated nclassdef
        fun generate_deserialization_init(nclassdef: AClassdef, per_attribute: Bool)
        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 = new Array[String]
                code.add """
redef init from_deserializer(v: Deserializer)
do
        super
        v.notify_of_creation self
"""

                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

                        var n_type = attribute.n_type
                        var type_name
                        if n_type == null then
                                # Use a place holder, we will replace it with the inferred type after the model phases
                                type_name = toolcontext.place_holder_type_name
                        else
                                type_name = n_type.type_name
                        end
                        var name = attribute.name

                        code.add """
        var {{{name}}} = v.deserialize_attribute("{{{name}}}")
        if not {{{name}}} isa {{{type_name}}} then
                # Check if it was a subjectent error
                v.errors.add new AttributeTypeError("TODO remove this arg on c_src regen",
                        self, "{{{name}}}", {{{name}}}, "{{{type_name}}}")

                # Clear subjacent error
                if v.keep_going == false then return
        else
                self.{{{name}}} = {{{name}}}
        end
"""
                end

                code.add "end"

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

        # Added to the abstract serialization service
        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)"
                        code.add "      do"
                else
                        toolcontext.error(deserializer_npropdef.location, "Error: `Deserializer::deserialize_class_intern` is generated and must not be defined, use `deserialize_class` instead.")
                        return
                end

                for nclassdef in nclassdefs do
                        var name = nclassdef.n_qid.n_id.text
                        if nclassdef.n_formaldefs.is_empty and
                           nclassdef.n_classkind isa AConcreteClasskind then

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

                code.add "              return super"
                code.add "      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

        redef fun process_nmodule(nmodule)
        do
                for npropdef in nmodule.inits_to_retype do
                        var mpropdef = npropdef.mpropdef
                        if mpropdef == null then continue # skip error
                        var v = new PreciseTypeVisitor(npropdef, mpropdef.mclassdef, toolcontext)
                        npropdef.accept_precise_type_visitor v
                end
        end
end

# Visitor on generated constructors to replace the expected type of deserialized attributes
private class PreciseTypeVisitor
        super Visitor

        var npropdef: AMethPropdef
        var mclassdef: MClassDef
        var toolcontext: ToolContext

        redef fun visit(n) do n.accept_precise_type_visitor(self)
end

redef class AIsaExpr
        redef fun accept_precise_type_visitor(v)
        do
                if n_type.collect_text != v.toolcontext.place_holder_type_name then return

                var attr_name = "_" + n_expr.collect_text
                for mattrdef in v.mclassdef.mpropdefs do
                        if mattrdef isa MAttributeDef and mattrdef.name == attr_name then
                                var new_ntype = v.toolcontext.parse_something(mattrdef.static_mtype.to_s)
                                n_type.replace_with new_ntype
                                break
                        end
                end
        end
end

redef class AAttrPropdef
        private fun name: String
        do
                return n_id2.text
        end
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 nclassdef isa AStdClassdef and nclassdef.n_qid.n_id.text == "Deserializer" then
                                return nclassdef
                        end
                end

                return null
        end

        private var inits_to_retype = new Array[AMethPropdef]

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