Module: GraphQL::InternalRepresentation::Rewrite

Includes:
Language
Included in:
StaticValidation::DefaultVisitor, StaticValidation::NoValidateVisitor
Defined in:
lib/graphql/internal_representation/rewrite.rb

Overview

While visiting an AST, build a normalized, flattened tree of Nodes.

No unions or interfaces are present in this tree, only object types.

Selections from the AST are attached to the object types they apply to.

Inline fragments and fragment spreads are preserved in InternalRepresentation::Node#ast_spreads, where they can be used to check for the presence of directives. This might not be sufficient for future directives, since the selections’ grouping is lost.

The rewritten query tree serves as the basis for the FieldsWillMerge validation.

Constant Summary collapse

NO_DIRECTIVES =
[].freeze

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from Language

serialize

Instance Attribute Details

#rewrite_documentObject (readonly)

Returns InternalRepresentation::Document.

Returns:

  • InternalRepresentation::Document



22
23
24
# File 'lib/graphql/internal_representation/rewrite.rb', line 22

def rewrite_document
  @rewrite_document
end

Instance Method Details

#initializeObject



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
# File 'lib/graphql/internal_representation/rewrite.rb', line 24

def initialize(*)
  super
  @query = context.query
  @rewrite_document = InternalRepresentation::Document.new
  # Hash<Nodes::FragmentSpread => Set<InternalRepresentation::Node>>
  # A record of fragment spreads and the irep nodes that used them
  @rewrite_spread_parents = Hash.new { |h, k| h[k] = Set.new }
  # Hash<Nodes::FragmentSpread => Scope>
  @rewrite_spread_scopes = {}
  # Array<Set<InternalRepresentation::Node>>
  # The current point of the irep_tree during visitation
  @rewrite_nodes_stack = []
  # Array<Scope>
  @rewrite_scopes_stack = []
  @rewrite_skip_nodes = Set.new

  # Resolve fragment spreads.
  # Fragment definitions got their own irep trees during visitation.
  # Those nodes are spliced in verbatim (not copied), but this is OK
  # because fragments are resolved from the "bottom up", each fragment
  # can be shared between its usages.
  context.on_dependency_resolve do |defn_ast_node, spread_ast_nodes, frag_ast_node|
    frag_name = frag_ast_node.name
    fragment_node = @rewrite_document.fragment_definitions[frag_name]

    if fragment_node
      spread_ast_nodes.each do |spread_ast_node|
        parent_nodes = @rewrite_spread_parents[spread_ast_node]
        parent_scope = @rewrite_spread_scopes[spread_ast_node]
        parent_nodes.each do |parent_node|
          parent_node.deep_merge_node(fragment_node, scope: parent_scope, merge_self: false)
        end
      end
    end
  end
end

#on_field(ast_node, ast_parent) ⇒ Object



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
# File 'lib/graphql/internal_representation/rewrite.rb', line 120

def on_field(ast_node, ast_parent)
  if skip?(ast_node)
    @rewrite_skip_nodes.add(ast_node)
  end

  if @rewrite_skip_nodes.empty?
    node_name = ast_node.alias || ast_node.name
    parent_nodes = @rewrite_nodes_stack.last
    next_nodes = []

    field_defn = context.field_definition
    if field_defn.nil?
      # It's a non-existent field
      new_scope = nil
    else
      field_return_type = field_defn.type
      @rewrite_scopes_stack.last.each do |scope_type|
        parent_nodes.each do |parent_node|
          node = parent_node.scoped_children[scope_type][node_name] ||= Node.new(
            parent: parent_node,
            name: node_name,
            owner_type: scope_type,
            query: @query,
            return_type: field_return_type,
          )
          node.ast_nodes << ast_node
          node.definitions << field_defn
          next_nodes << node
        end
      end
      new_scope = Scope.new(@query, field_return_type.unwrap)
    end

    @rewrite_nodes_stack.push(next_nodes)
    @rewrite_scopes_stack.push(new_scope)
  end

  super

  if @rewrite_skip_nodes.empty?
    @rewrite_nodes_stack.pop
    @rewrite_scopes_stack.pop
  end

  if @rewrite_skip_nodes.include?(ast_node)
    @rewrite_skip_nodes.delete(ast_node)
  end
end

#on_fragment_definition(ast_node, parent) ⇒ Object



71
72
73
# File 'lib/graphql/internal_representation/rewrite.rb', line 71

def on_fragment_definition(ast_node, parent)
  push_root_node(ast_node, @rewrite_document.fragment_definitions) { super }
end

#on_fragment_spread(ast_node, ast_parent) ⇒ Object



169
170
171
172
173
174
175
176
# File 'lib/graphql/internal_representation/rewrite.rb', line 169

def on_fragment_spread(ast_node, ast_parent)
  if @rewrite_skip_nodes.empty? && !skip?(ast_node)
    # Register the irep nodes that depend on this AST node:
    @rewrite_spread_parents[ast_node].merge(@rewrite_nodes_stack.last)
    @rewrite_spread_scopes[ast_node] = @rewrite_scopes_stack.last
  end
  super
end

#on_inline_fragment(node, parent) ⇒ Object



97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
# File 'lib/graphql/internal_representation/rewrite.rb', line 97

def on_inline_fragment(node, parent)
  # Inline fragments provide two things to the rewritten tree:
  # - They _may_ narrow the scope by their type condition
  # - They _may_ apply their directives to their children
  if skip?(node)
    @rewrite_skip_nodes.add(node)
  end

  if @rewrite_skip_nodes.empty?
    @rewrite_scopes_stack.push(@rewrite_scopes_stack.last.enter(context.type_definition))
  end

  super

  if @rewrite_skip_nodes.empty?
    @rewrite_scopes_stack.pop
  end

  if @rewrite_skip_nodes.include?(node)
    @rewrite_skip_nodes.delete(node)
  end
end

#on_operation_definition(ast_node, parent) ⇒ Object



67
68
69
# File 'lib/graphql/internal_representation/rewrite.rb', line 67

def on_operation_definition(ast_node, parent)
  push_root_node(ast_node, @rewrite_document.operation_definitions) { super }
end

#operationsHash<String, Node>

Returns Roots of this query.

Returns:

  • (Hash<String, Node>)

    Roots of this query



62
63
64
65
# File 'lib/graphql/internal_representation/rewrite.rb', line 62

def operations
  warn "#{self.class}#operations is deprecated; use `document.operation_definitions` instead"
  @document.operation_definitions
end

#push_root_node(ast_node, definitions) ⇒ Object



75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
# File 'lib/graphql/internal_representation/rewrite.rb', line 75

def push_root_node(ast_node, definitions)
  # Either QueryType or the fragment type condition
  owner_type = context.type_definition
  defn_name = ast_node.name

  node = Node.new(
    parent: nil,
    name: defn_name,
    owner_type: owner_type,
    query: @query,
    ast_nodes: [ast_node],
    return_type: owner_type,
  )

  definitions[defn_name] = node
  @rewrite_scopes_stack.push(Scope.new(@query, owner_type))
  @rewrite_nodes_stack.push([node])
  yield
  @rewrite_nodes_stack.pop
  @rewrite_scopes_stack.pop
end

#skip?(ast_node) ⇒ Boolean

Returns:

  • (Boolean)


178
179
180
181
# File 'lib/graphql/internal_representation/rewrite.rb', line 178

def skip?(ast_node)
  dir = ast_node.directives
  dir.any? && !GraphQL::Execution::DirectiveChecks.include?(dir, @query)
end