132 lines
3.6 KiB
Crystal
132 lines
3.6 KiB
Crystal
module DB
|
|
# Transactions should be started from `DB#transaction`, `Connection#transaction`
|
|
# or `Connection#begin_transaction`.
|
|
#
|
|
# Use `Transaction#connection` to submit statements to the database.
|
|
#
|
|
# Use `Transaction#commit` or `Transaction#rollback` to close the ongoing transaction
|
|
# explicitly. Or refer to `BeginTransaction#transaction` for documentation on how to
|
|
# use `#transaction(&block)` methods in `DB` and `Connection`.
|
|
#
|
|
# Nested transactions are supported by using sql `SAVEPOINT`. To start a nested
|
|
# transaction use `Transaction#transaction` or `Transaction#begin_transaction`.
|
|
#
|
|
abstract class Transaction
|
|
include Disposable
|
|
include BeginTransaction
|
|
|
|
abstract def connection : Connection
|
|
|
|
# commits the current transaction
|
|
def commit
|
|
close!
|
|
end
|
|
|
|
# rollbacks the current transaction
|
|
def rollback
|
|
close!
|
|
end
|
|
|
|
private def close!
|
|
raise DB::Error.new("Transaction already closed") if closed?
|
|
close
|
|
end
|
|
|
|
abstract def release_from_nested_transaction
|
|
end
|
|
|
|
class TopLevelTransaction < Transaction
|
|
getter connection : Connection
|
|
# :nodoc:
|
|
property savepoint_name : String? = nil
|
|
|
|
def initialize(@connection : Connection)
|
|
@nested_transaction = false
|
|
@connection.perform_begin_transaction
|
|
end
|
|
|
|
def commit
|
|
@connection.perform_commit_transaction
|
|
super
|
|
end
|
|
|
|
def rollback
|
|
@connection.perform_rollback_transaction
|
|
super
|
|
end
|
|
|
|
protected def do_close
|
|
connection.release_from_transaction
|
|
end
|
|
|
|
def begin_transaction : Transaction
|
|
raise DB::Error.new("There is an existing nested transaction in this transaction") if @nested_transaction
|
|
@nested_transaction = true
|
|
create_save_point_transaction(self)
|
|
end
|
|
|
|
# :nodoc:
|
|
def create_save_point_transaction(parent : Transaction) : SavePointTransaction
|
|
# TODO should we wrap this in a mutex?
|
|
previous_savepoint = @savepoint_name
|
|
savepoint_name = if previous_savepoint
|
|
previous_savepoint.succ
|
|
else
|
|
# random prefix to avoid determinism
|
|
"cr_#{@connection.object_id}_#{Random.rand(10_000)}_00001"
|
|
end
|
|
|
|
@savepoint_name = savepoint_name
|
|
|
|
create_save_point_transaction(parent, savepoint_name)
|
|
end
|
|
|
|
protected def create_save_point_transaction(parent : Transaction, savepoint_name : String) : SavePointTransaction
|
|
SavePointTransaction.new(parent, savepoint_name)
|
|
end
|
|
|
|
# :nodoc:
|
|
def release_from_nested_transaction
|
|
@nested_transaction = false
|
|
end
|
|
end
|
|
|
|
class SavePointTransaction < Transaction
|
|
getter connection : Connection
|
|
|
|
def initialize(@parent : Transaction, @savepoint_name : String)
|
|
@nested_transaction = false
|
|
@connection = @parent.connection
|
|
@connection.perform_create_savepoint(@savepoint_name)
|
|
end
|
|
|
|
def commit
|
|
@connection.perform_release_savepoint(@savepoint_name)
|
|
super
|
|
end
|
|
|
|
def rollback
|
|
@connection.perform_rollback_savepoint(@savepoint_name)
|
|
super
|
|
end
|
|
|
|
protected def do_close
|
|
@parent.release_from_nested_transaction
|
|
end
|
|
|
|
def begin_transaction : Transaction
|
|
raise DB::Error.new("There is an existing nested transaction in this transaction") if @nested_transaction
|
|
@nested_transaction = true
|
|
create_save_point_transaction(self)
|
|
end
|
|
|
|
def create_save_point_transaction(parent : Transaction)
|
|
@parent.create_save_point_transaction(parent)
|
|
end
|
|
|
|
def release_from_nested_transaction
|
|
@nested_transaction = false
|
|
end
|
|
end
|
|
end
|