aboutsummaryrefslogtreecommitdiffstats
path: root/activerecord/lib/active_record/relation/predicate_builder.rb
blob: 8dbff849508c02915f110942d7d54e9014118ef2 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
module ActiveRecord
  class PredicateBuilder # :nodoc:
    require "active_record/relation/predicate_builder/array_handler"
    require "active_record/relation/predicate_builder/association_query_handler"
    require "active_record/relation/predicate_builder/base_handler"
    require "active_record/relation/predicate_builder/basic_object_handler"
    require "active_record/relation/predicate_builder/class_handler"
    require "active_record/relation/predicate_builder/polymorphic_array_handler"
    require "active_record/relation/predicate_builder/range_handler"
    require "active_record/relation/predicate_builder/relation_handler"

    delegate :resolve_column_aliases, to: :table

    def initialize(table)
      @table = table
      @handlers = []

      register_handler(BasicObject, BasicObjectHandler.new)
      register_handler(Class, ClassHandler.new(self))
      register_handler(Base, BaseHandler.new(self))
      register_handler(Range, RangeHandler.new)
      register_handler(RangeHandler::RangeWithBinds, RangeHandler.new)
      register_handler(Relation, RelationHandler.new)
      register_handler(Array, ArrayHandler.new(self))
      register_handler(AssociationQueryValue, AssociationQueryHandler.new(self))
      register_handler(PolymorphicArrayValue, PolymorphicArrayHandler.new(self))
    end

    def build_from_hash(attributes)
      attributes = convert_dot_notation_to_hash(attributes)
      expand_from_hash(attributes)
    end

    def create_binds(attributes)
      attributes = convert_dot_notation_to_hash(attributes)
      create_binds_for_hash(attributes)
    end

    def expand(column, value)
      # Find the foreign key when using queries such as:
      # Post.where(author: author)
      #
      # For polymorphic relationships, find the foreign key and type:
      # PriceEstimate.where(estimate_of: treasure)
      value = AssociationQueryHandler.value_for(table, column, value) if table.associated_with?(column)
      build(table.arel_attribute(column), value)
    end

    def self.references(attributes)
      attributes.map do |key, value|
        if value.is_a?(Hash)
          key
        else
          key = key.to_s
          key.split(".".freeze).first if key.include?(".".freeze)
        end
      end.compact
    end

    # Define how a class is converted to Arel nodes when passed to +where+.
    # The handler can be any object that responds to +call+, and will be used
    # for any value that +===+ the class given. For example:
    #
    #     MyCustomDateRange = Struct.new(:start, :end)
    #     handler = proc do |column, range|
    #       Arel::Nodes::Between.new(column,
    #         Arel::Nodes::And.new([range.start, range.end])
    #       )
    #     end
    #     ActiveRecord::PredicateBuilder.new("users").register_handler(MyCustomDateRange, handler)
    def register_handler(klass, handler)
      @handlers.unshift([klass, handler])
    end

    def build(attribute, value)
      handler_for(value).call(attribute, value)
    end

    protected

    attr_reader :table

    def expand_from_hash(attributes)
      return ["1=0"] if attributes.empty?

      attributes.flat_map do |key, value|
        if value.is_a?(Hash)
          associated_predicate_builder(key).expand_from_hash(value)
        else
          expand(key, value)
        end
      end
    end


    def create_binds_for_hash(attributes)
      result = attributes.dup
      binds = []

      attributes.each do |column_name, value|
        case value
        when Hash
          attrs, bvs = associated_predicate_builder(column_name).create_binds_for_hash(value)
          result[column_name] = attrs
          binds += bvs
        when Relation
          binds += value.bound_attributes
        when Range
          first = value.begin
          last = value.end
          unless first.respond_to?(:infinite?) && first.infinite?
            binds << build_bind_param(column_name, first)
            first = Arel::Nodes::BindParam.new
          end
          unless last.respond_to?(:infinite?) && last.infinite?
            binds << build_bind_param(column_name, last)
            last = Arel::Nodes::BindParam.new
          end

          result[column_name] = RangeHandler::RangeWithBinds.new(first, last, value.exclude_end?)
        else
          if can_be_bound?(column_name, value)
            result[column_name] = Arel::Nodes::BindParam.new
            binds << build_bind_param(column_name, value)
          end
        end
      end

      [result, binds]
    end

    private

    def associated_predicate_builder(association_name)
      self.class.new(table.associated_table(association_name))
    end

    def convert_dot_notation_to_hash(attributes)
      dot_notation = attributes.select do |k, v|
        k.include?(".".freeze) && !v.is_a?(Hash)
      end

      dot_notation.each_key do |key|
        table_name, column_name = key.split(".".freeze)
        value = attributes.delete(key)
        attributes[table_name] ||= {}

        attributes[table_name] = attributes[table_name].merge(column_name => value)
      end

      attributes
    end

    def handler_for(object)
      @handlers.detect { |klass, _| klass === object }.last
    end

    def can_be_bound?(column_name, value)
      !value.nil? &&
        handler_for(value).is_a?(BasicObjectHandler) &&
        !table.associated_with?(column_name)
    end

    def build_bind_param(column_name, value)
      Relation::QueryAttribute.new(column_name.to_s, value, table.type(column_name))
    end
  end
end