module ActiveRecord module ConnectionAdapters class SchemaCache attr_reader :primary_keys, :tables, :version attr_accessor :connection def initialize(conn) @connection = conn @columns = {} @columns_hash = {} @primary_keys = {} @tables = {} prepare_default_proc end # A cached lookup for table existence. def table_exists?(name) return @tables[name] if @tables.key? name @tables[name] = connection.table_exists?(name) end # Add internal cache for table with +table_name+. def add(table_name) if table_exists?(table_name) @primary_keys[table_name] @columns[table_name] @columns_hash[table_name] end end # Get the columns for a table def columns(table = nil) if table @columns[table] else @columns end end # Get the columns for a table as a hash, key is the column name # value is the column object. def columns_hash(table = nil) if table @columns_hash[table] else @columns_hash end end # Clears out internal caches def clear! @columns.clear @columns_hash.clear @primary_keys.clear @tables.clear @version = nil end # Clear out internal caches for table with +table_name+. def clear_table_cache!(table_name) @columns.delete table_name @columns_hash.delete table_name @primary_keys.delete table_name @tables.delete table_name end def marshal_dump # if we get current version during initialization, it happens stack over flow. @version = ActiveRecord::Migrator.current_version [@version] + [:@columns, :@columns_hash, :@primary_keys, :@tables].map do |val| self.instance_variable_get(val).inject({}) { |h, v| h[v[0]] = v[1]; h } end end def marshal_load(array) @version, @columns, @columns_hash, @primary_keys, @tables = array prepare_default_proc end private def prepare_default_proc @columns.default_proc = Proc.new do |h, table_name| h[table_name] = connection.columns(table_name) end @columns_hash.default_proc = Proc.new do |h, table_name| h[table_name] = Hash[columns[table_name].map { |col| [col.name, col] }] end @primary_keys.default_proc = Proc.new do |h, table_name| h[table_name] = table_exists?(table_name) ? connection.primary_key(table_name) : nil end end end end end