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# Adds support for WITH statements when using PostgreSQL. The code here is taken
# from https://github.com/shmay/ctes_in_my_pg which at the time of writing has
# not been pushed to RubyGems. The license of this repository is as follows:
#
# The MIT License (MIT)
#
# Copyright (c) 2012 Dan McClain
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.
module ActiveRecord
class Relation
class Merger # :nodoc:
def normal_values
NORMAL_VALUES + [:with]
end
end
end
end
module ActiveRecord::Querying
delegate :with, to: :all
end
module ActiveRecord
class Relation
# WithChain objects act as placeholder for queries in which #with does not have any parameter.
# In this case, #with must be chained with #recursive to return a new relation.
class WithChain
def initialize(scope)
@scope = scope
end
# Returns a new relation expressing WITH RECURSIVE
def recursive(*args)
@scope.with_values += args
@scope.recursive_value = true
@scope
end
end
def with_values
@values[:with] || []
end
def with_values=(values)
raise ImmutableRelation if @loaded
@values[:with] = values
end
def recursive_value=(value)
raise ImmutableRelation if @loaded
@values[:recursive] = value
end
def recursive_value
@values[:recursive]
end
def with(opts = :chain, *rest)
if opts == :chain
WithChain.new(spawn)
elsif opts.blank?
self
else
spawn.with!(opts, *rest)
end
end
def with!(opts = :chain, *rest) # :nodoc:
if opts == :chain
WithChain.new(self)
else
self.with_values += [opts] + rest
self
end
end
def build_arel(aliases)
arel = super
build_with(arel) if @values[:with]
arel
end
def build_with(arel)
with_statements = with_values.flat_map do |with_value|
case with_value
when String
with_value
when Hash
with_value.map do |name, expression|
case expression
when String
select = Arel::Nodes::SqlLiteral.new "(#{expression})"
when ActiveRecord::Relation, Arel::SelectManager
select = Arel::Nodes::SqlLiteral.new "(#{expression.to_sql})"
end
Arel::Nodes::As.new Arel::Nodes::SqlLiteral.new("\"#{name}\""), select
end
when Arel::Nodes::As
with_value
end
end
unless with_statements.empty?
if recursive_value
arel.with :recursive, with_statements
else
arel.with with_statements
end
end
end
end
end
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