# File activerecord/lib/active_record/connection_adapters/schema_cache.rb, line 7
def initialize(conn)
  @connection = conn

  @columns      = {}
  @columns_hash = {}
  @primary_keys = {}
  @data_sources = {}
end

# File activerecord/lib/active_record/connection_adapters/schema_cache.rb, line 40
def add(table_name)
  if data_source_exists?(table_name)
    primary_keys(table_name)
    columns(table_name)
    columns_hash(table_name)
  end
end

# File activerecord/lib/active_record/connection_adapters/schema_cache.rb, line 68
def clear!
  @columns.clear
  @columns_hash.clear
  @primary_keys.clear
  @data_sources.clear
  @version = nil
end

# File activerecord/lib/active_record/connection_adapters/schema_cache.rb, line 81
def clear_data_source_cache!(name)
  @columns.delete name
  @columns_hash.delete name
  @primary_keys.delete name
  @data_sources.delete name
end

# File activerecord/lib/active_record/connection_adapters/schema_cache.rb, line 55
def columns(table_name)
  @columns[table_name] ||= connection.columns(table_name)
end

# File activerecord/lib/active_record/connection_adapters/schema_cache.rb, line 61
def columns_hash(table_name)
  @columns_hash[table_name] ||= Hash[columns(table_name).map { |col|
    [col.name, col]
  }]
end

# File activerecord/lib/active_record/connection_adapters/schema_cache.rb, line 29
def data_source_exists?(name)
  prepare_data_sources if @data_sources.empty?
  return @data_sources[name] if @data_sources.key? name

  @data_sources[name] = connection.data_source_exists?(name)
end

# File activerecord/lib/active_record/connection_adapters/schema_cache.rb, line 48
def data_sources(name)
  @data_sources[name]
end

# File activerecord/lib/active_record/connection_adapters/schema_cache.rb, line 16
def initialize_dup(other)
  super
  @columns      = @columns.dup
  @columns_hash = @columns_hash.dup
  @primary_keys = @primary_keys.dup
  @data_sources = @data_sources.dup
end

# File activerecord/lib/active_record/connection_adapters/schema_cache.rb, line 90
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, @data_sources]
end

# File activerecord/lib/active_record/connection_adapters/schema_cache.rb, line 96
def marshal_load(array)
  @version, @columns, @columns_hash, @primary_keys, @data_sources = array
end

# File activerecord/lib/active_record/connection_adapters/schema_cache.rb, line 24
def primary_keys(table_name)
  @primary_keys[table_name] ||= data_source_exists?(table_name) ? connection.primary_key(table_name) : nil
end

# File activerecord/lib/active_record/connection_adapters/schema_cache.rb, line 76
def size
  [@columns, @columns_hash, @primary_keys, @data_sources].map(&:size).inject :+
end