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module ActiveRecord
module ConnectionAdapters
class SchemaCache
attr_reader :columns, :columns_hash, :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
# 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
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