Module: Squeel::Adapters::ActiveRecord::Relation

Defined in:
lib/squeel/adapters/active_record/relation.rb

Constant Summary collapse

JoinAssociation = 
::ActiveRecord::Associations::JoinDependency::JoinAssociation
JoinDependency = 
::ActiveRecord::Associations::JoinDependency

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#join_dependency ⇒ Object 



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# File 'lib/squeel/adapters/active_record/relation.rb', line 14

def join_dependency
  @join_dependency ||= (build_join_dependency(table.from(table), @joins_values) && @join_dependency)
end

Class Method Details

.included(base) ⇒ Object

ZOMG ALIAS_METHOD_CHAIN IS BELOW. HIDE YOUR EYES! … … … Since you’re still looking, let me explain this horrible transgression you see before you. You see, Relation#where_values_hash is defined on the ActiveRecord::Relation class. Since it’s defined there, but I would very much like to modify its behavior, I have three choices.

  1. Inherit from ActiveRecord::Relation in a Squeel::Relation class, and make an attempt to usurp all of the various calls to methods on ActiveRecord::Relation by doing some really evil stuff with constant reassignment, all for the sake of being able to use super().

  2. Submit a patch to Rails core, breaking this method off into another module, all for my own selfish desire to use super() while mucking about in Rails internals.

  3. Use alias_method_chain, and say 10 hail Hanssons as penance.

I opted to go with #3. Except for the hail Hansson thing. Unless you’re DHH, in which case, I totally said them.



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# File 'lib/squeel/adapters/active_record/relation.rb', line 277

def self.included(base)
  base.class_eval do
    alias_method_chain :where_values_hash, :squeel
  end
end

Instance Method Details

#build_arel ⇒ Object 



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# File 'lib/squeel/adapters/active_record/relation.rb', line 63

def build_arel
  arel = table.from table

  build_join_dependency(arel, @joins_values) unless @joins_values.empty?

  predicate_viz = predicate_visitor

  collapse_wheres(arel, predicate_viz.accept((@where_values - ['']).uniq))

  arel.having(*predicate_viz.accept(@having_values.uniq.reject{|h| h.blank?})) unless @having_values.empty?

  arel.take(connection.sanitize_limit(@limit_value)) if @limit_value
  arel.skip(@offset_value) if @offset_value

  arel.group(*@group_values.uniq.reject{|g| g.blank?}) unless @group_values.empty?

  unless @order_values.empty?
    order_viz = order_visitor
    arel.order(*order_viz.accept(@order_values.uniq.reject{|o| o.blank?}))
  end

  build_select(arel, select_visitor.accept(@select_values.uniq))

  arel.from(@from_value) if @from_value
  arel.lock(@lock_value) if @lock_value

  arel
end

#build_join_dependency(manager, joins) ⇒ Object 



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# File 'lib/squeel/adapters/active_record/relation.rb', line 92

def build_join_dependency(manager, joins)
  buckets = joins.group_by do |join|
    case join
    when String
      'string_join'
    when Hash, Symbol, Array, Nodes::Stub, Nodes::Join, Nodes::KeyPath
      'association_join'
    when JoinAssociation
      'stashed_join'
    when Arel::Nodes::Join
      'join_node'
    else
      raise 'unknown class: %s' % join.class.name
    end
  end

  association_joins         = buckets['association_join'] || []
  stashed_association_joins = buckets['stashed_join'] || []
  join_nodes                = buckets['join_node'] || []
  string_joins              = (buckets['string_join'] || []).map { |x|
    x.strip
  }.uniq

  join_list = custom_join_ast(manager, string_joins)

  # All of this duplication just to add
  self.join_dependency = JoinDependency.new(
    @klass,
    association_joins,
    join_list
  )

  join_nodes.each do |join|
    join_dependency.alias_tracker.aliased_name_for(join.left.name.downcase)
  end

  join_dependency.graft(*stashed_association_joins)

  @implicit_readonly = true unless association_joins.empty? && stashed_association_joins.empty?

  join_dependency.join_associations.each do |association|
    association.join_to(manager)
  end

  manager.join_sources.concat join_nodes.uniq
  manager.join_sources.concat join_list

  manager
end

#build_where(opts, other = []) ⇒ Object 



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# File 'lib/squeel/adapters/active_record/relation.rb', line 164

def build_where(opts, other = [])
  case opts
  when String, Array
    super
  else  # Let's prevent PredicateBuilder from doing its thing
    [opts, *other].map do |arg|
      case arg
      when Array  # Just in case there's an array in there somewhere
        @klass.send(:sanitize_sql, arg)
      when Hash
        @klass.send(:expand_hash_conditions_for_aggregates, arg)
      else
        arg
      end
    end
  end
end

#collapse_wheres(arel, wheres) ⇒ Object 



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# File 'lib/squeel/adapters/active_record/relation.rb', line 206

def collapse_wheres(arel, wheres)
  wheres = [wheres] unless Array === wheres
  binaries = wheres.grep(Arel::Nodes::Binary)

  groups = binaries.group_by {|b| [b.class, b.left]}

  groups.each do |_, bins|
    arel.where(Arel::Nodes::And.new(bins))
  end

  (wheres - binaries).each do |where|
    where = Arel.sql(where) if String === where
    arel.where(Arel::Nodes::Grouping.new(where))
  end
end

#debug_sql ⇒ Object

Simulate the logic that occurs in #to_a

This will let us get a dump of the SQL that will be run against the DB for debug purposes without actually running the query.



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# File 'lib/squeel/adapters/active_record/relation.rb', line 241

def debug_sql
  if eager_loading?
    including = (@eager_load_values + @includes_values).uniq
    join_dependency = JoinDependency.new(@klass, including, [])
    construct_relation_for_association_find(join_dependency).to_sql
  else
    arel.to_sql
  end
end

#find_equality_predicates(nodes) ⇒ Object 



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# File 'lib/squeel/adapters/active_record/relation.rb', line 222

def find_equality_predicates(nodes)
  nodes.map { |node|
    case node
    when Arel::Nodes::Equality
      node
    when Arel::Nodes::Grouping
      find_equality_predicates([node.expr])
    when Arel::Nodes::And
      find_equality_predicates(node.children)
    else
      nil
    end
  }.compact.flatten
end

#having(*args) ⇒ Object 



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# File 'lib/squeel/adapters/active_record/relation.rb', line 198

def having(*args)
  if block_given? && args.empty?
    super(DSL.evaluate &Proc.new)
  else
    super
  end
end

#infer_association_for_relation_merge(r) ⇒ Object 



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# File 'lib/squeel/adapters/active_record/relation.rb', line 52

def infer_association_for_relation_merge(r)
  default_association = reflect_on_all_associations.detect {|a| a.class_name == r.klass.name}
  default_association ? default_association.name : r.table_name.to_sym
end

#joins(*args) ⇒ Object 



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# File 'lib/squeel/adapters/active_record/relation.rb', line 190

def joins(*args)
  if block_given? && args.empty?
    super(DSL.evaluate &Proc.new)
  else
    super
  end
end

#merge(r, association_name = nil) ⇒ Object 



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# File 'lib/squeel/adapters/active_record/relation.rb', line 36

def merge(r, association_name = nil)
  if association_name || relation_with_different_base?(r)
    r = r.clone
    association_name ||= infer_association_for_relation_merge(r)
    prepare_relation_for_association_merge!(r, association_name)
    self.joins_values += [association_name] if reflect_on_association(association_name)
  end

  super(r)
end

#order(*args) ⇒ Object 



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# File 'lib/squeel/adapters/active_record/relation.rb', line 182

def order(*args)
  if block_given? && args.empty?
    super(DSL.evaluate &Proc.new)
  else
    super
  end
end

#order_visitor ⇒ Object 



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# File 'lib/squeel/adapters/active_record/relation.rb', line 30

def order_visitor
  Visitors::OrderVisitor.new(
    Contexts::JoinDependencyContext.new(join_dependency)
  )
end

#predicate_visitor ⇒ Object 



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# File 'lib/squeel/adapters/active_record/relation.rb', line 24

def predicate_visitor
  Visitors::PredicateVisitor.new(
    Contexts::JoinDependencyContext.new(join_dependency)
  )
end

#prepare_relation_for_association_merge!(r, association_name) ⇒ Object 



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# File 'lib/squeel/adapters/active_record/relation.rb', line 57

def prepare_relation_for_association_merge!(r, association_name)
  r.where_values.map! {|w| Squeel::Visitors::PredicateVisitor.can_accept?(w) ? {association_name => w} : w}
  r.having_values.map! {|h| Squeel::Visitors::PredicateVisitor.can_accept?(h) ? {association_name => h} : h}
  r.joins_values.map! {|j| [Symbol, Hash, Nodes::Stub, Nodes::Join].include?(j.class) ? {association_name => j} : j}
end

#relation_with_different_base?(r) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/squeel/adapters/active_record/relation.rb', line 47

def relation_with_different_base?(r)
  ::ActiveRecord::Relation === r &&
  base_class.name != r.klass.base_class.name
end

#select(value = Proc.new) ⇒ Object 



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# File 'lib/squeel/adapters/active_record/relation.rb', line 142

def select(value = Proc.new)
  if block_given? && Proc === value
    if value.arity > 0
      to_a.select {|*block_args| value.call(*block_args)}
    else
      relation = clone
      relation.select_values += Array.wrap(DSL.evaluate &value)
      relation
    end
  else
    super
  end
end

#select_visitor ⇒ Object 



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# File 'lib/squeel/adapters/active_record/relation.rb', line 18

def select_visitor
  Visitors::SelectVisitor.new(
    Contexts::JoinDependencyContext.new(join_dependency)
  )
end

#where(opts = Proc.new, *rest) ⇒ Object 



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# File 'lib/squeel/adapters/active_record/relation.rb', line 156

def where(opts = Proc.new, *rest)
  if block_given? && Proc === opts
    super(DSL.evaluate &opts)
  else
    super
  end
end

#where_values_hash_with_squeel ⇒ Object 



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# File 'lib/squeel/adapters/active_record/relation.rb', line 283

def where_values_hash_with_squeel
  equalities = find_equality_predicates(predicate_visitor.accept(@where_values))

  Hash[equalities.map { |where| [where.left.name, where.right] }]
end