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require 'active_support/core_ext/string/conversions'
module ActiveRecord
module Associations
# Keeps track of table aliases for ActiveRecord::Associations::ClassMethods::JoinDependency and
# ActiveRecord::Associations::ThroughAssociationScope
class AliasTracker # :nodoc:
# table_joins is an array of arel joins which might conflict with the aliases we assign here
def initialize(table_joins = nil)
@aliases = Hash.new
@table_joins = table_joins
end
def aliased_name_for(table_name, aliased_name = nil)
aliased_name ||= table_name
initialize_count_for(table_name) if @aliases[table_name].nil?
if @aliases[table_name].zero?
# If it's zero, we can have our table_name
@aliases[table_name] = 1
table_name
else
# Otherwise, we need to use an alias
aliased_name = connection.table_alias_for(aliased_name)
initialize_count_for(aliased_name) if @aliases[aliased_name].nil?
# Update the count
@aliases[aliased_name] += 1
if @aliases[aliased_name] > 1
"#{truncate(aliased_name)}_#{@aliases[aliased_name]}"
else
aliased_name
end
end
end
def pluralize(table_name)
ActiveRecord::Base.pluralize_table_names ? table_name.to_s.pluralize : table_name
end
private
def initialize_count_for(name)
@aliases[name] = 0
unless @table_joins.nil? || Arel::Table === @table_joins
# quoted_name should be downcased as some database adapters (Oracle) return quoted name in uppercase
quoted_name = connection.quote_table_name(name).downcase
@aliases[name] += @table_joins.grep(Arel::Nodes::Join).map { |join|
right = join.right
case right
when Arel::Table
right.name.downcase == name ? 1 : 0
when String
# Table names + table aliases
right.downcase.scan(
/join(?:\s+\w+)?\s+(\S+\s+)?#{quoted_name}\son/
).size
else
0
end
}.sum
end
@aliases[name]
end
def truncate(name)
name[0..connection.table_alias_length-3]
end
def connection
ActiveRecord::Base.connection
end
end
end
end
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