diff options
Diffstat (limited to 'activerecord/lib/active_record/associations/alias_tracker.rb')
-rw-r--r-- | activerecord/lib/active_record/associations/alias_tracker.rb | 73 |
1 files changed, 73 insertions, 0 deletions
diff --git a/activerecord/lib/active_record/associations/alias_tracker.rb b/activerecord/lib/active_record/associations/alias_tracker.rb new file mode 100644 index 0000000000..64582188b6 --- /dev/null +++ b/activerecord/lib/active_record/associations/alias_tracker.rb @@ -0,0 +1,73 @@ +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: + # other_sql is some other sql which might conflict with the aliases we assign here. Therefore + # we store other_sql so that we can scan it before assigning a specific name. + def initialize(other_sql = nil) + @aliases = Hash.new + @other_sql = other_sql.to_s.downcase + 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 @other_sql.blank? + # quoted_name should be downcased as some database adapters (Oracle) return quoted name in uppercase + quoted_name = connection.quote_table_name(name.downcase).downcase + + # Table names + @aliases[name] += @other_sql.scan(/join(?:\s+\w+)?\s+#{quoted_name}\son/).size + + # Table aliases + @aliases[name] += @other_sql.scan(/join(?:\s+\w+)?\s+\S+\s+#{quoted_name}\son/).size + end + + @aliases[name] + end + + def truncate(name) + name[0..connection.table_alias_length-3] + end + + def connection + ActiveRecord::Base.connection + end + end + end +end |