2016-11-16 02:46:11 +00:00
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module DB
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abstract class Transaction
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include Disposable
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2016-12-13 19:15:25 +00:00
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include BeginTransaction
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2016-11-16 02:46:11 +00:00
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abstract def connection : Connection
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def commit
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close!
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end
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def rollback
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close!
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end
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private def close!
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raise DB::Error.new("Transaction already closed") if closed?
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close
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end
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2016-12-13 19:15:25 +00:00
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abstract def release_from_nested_transaction
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2016-11-16 02:46:11 +00:00
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end
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class TopLevelTransaction < Transaction
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getter connection
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2016-12-13 19:15:25 +00:00
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# :nodoc:
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property savepoint_name : String? = nil
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2016-11-16 02:46:11 +00:00
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def initialize(@connection : Connection)
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2016-12-13 19:15:25 +00:00
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@nested_transaction = false
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2016-11-16 02:46:11 +00:00
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@connection.perform_begin_transaction
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end
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def commit
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@connection.perform_commit_transaction
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2016-12-13 19:15:25 +00:00
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super
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2016-11-16 02:46:11 +00:00
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end
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def rollback
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@connection.perform_rollback_transaction
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2016-12-13 19:15:25 +00:00
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super
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2016-11-16 02:46:11 +00:00
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end
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protected def do_close
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connection.release_from_transaction
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end
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2016-12-13 19:15:25 +00:00
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def begin_transaction : Transaction
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raise DB::Error.new("There is an existing nested transaction in this transaction") if @nested_transaction
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@nested_transaction = true
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create_save_point_transaction(self)
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end
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# :nodoc:
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def create_save_point_transaction(parent : Transaction) : SavePointTransaction
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# TODO should we wrap this in a mutex?
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previous_savepoint = @savepoint_name
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savepoint_name = if previous_savepoint
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previous_savepoint.succ
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else
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# random prefix to avoid determinism
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2016-12-14 14:07:17 +00:00
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"cr_#{@connection.object_id}_#{Random.rand(10_000)}_00001"
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2016-12-13 19:15:25 +00:00
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end
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@savepoint_name = savepoint_name
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create_save_point_transaction(parent, savepoint_name)
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end
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protected def create_save_point_transaction(parent : Transaction, savepoint_name : String) : SavePointTransaction
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SavePointTransaction.new(parent, savepoint_name)
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end
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# :nodoc:
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def release_from_nested_transaction
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@nested_transaction = false
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end
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end
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class SavePointTransaction < Transaction
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getter connection : Connection
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def initialize(@parent : Transaction,
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@savepoint_name : String)
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@nested_transaction = false
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@connection = @parent.connection
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@connection.perform_create_savepoint(@savepoint_name)
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end
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def commit
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@connection.perform_release_savepoint(@savepoint_name)
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super
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end
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def rollback
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@connection.perform_rollback_savepoint(@savepoint_name)
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super
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end
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protected def do_close
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@parent.release_from_nested_transaction
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end
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def begin_transaction : Transaction
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raise DB::Error.new("There is an existing nested transaction in this transaction") if @nested_transaction
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@nested_transaction = true
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create_save_point_transaction(self)
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end
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def create_save_point_transaction(parent : Transaction)
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@parent.create_save_point_transaction(parent)
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end
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def release_from_nested_transaction
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@nested_transaction = false
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end
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2016-11-16 02:46:11 +00:00
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end
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end
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