/usr/lib/ruby/vendor_ruby/sequel/database/transactions.rb is in ruby-sequel 4.1.1-1.
This file is owned by root:root, with mode 0o644.
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class Database
# ---------------------
# :section: 8 - Methods related to database transactions
# Database transactions make multiple queries atomic, so
# that either all of the queries take effect or none of
# them do.
# ---------------------
SQL_BEGIN = 'BEGIN'.freeze
SQL_COMMIT = 'COMMIT'.freeze
SQL_RELEASE_SAVEPOINT = 'RELEASE SAVEPOINT autopoint_%d'.freeze
SQL_ROLLBACK = 'ROLLBACK'.freeze
SQL_ROLLBACK_TO_SAVEPOINT = 'ROLLBACK TO SAVEPOINT autopoint_%d'.freeze
SQL_SAVEPOINT = 'SAVEPOINT autopoint_%d'.freeze
TRANSACTION_BEGIN = 'Transaction.begin'.freeze
TRANSACTION_COMMIT = 'Transaction.commit'.freeze
TRANSACTION_ROLLBACK = 'Transaction.rollback'.freeze
TRANSACTION_ISOLATION_LEVELS = {:uncommitted=>'READ UNCOMMITTED'.freeze,
:committed=>'READ COMMITTED'.freeze,
:repeatable=>'REPEATABLE READ'.freeze,
:serializable=>'SERIALIZABLE'.freeze}
# The default transaction isolation level for this database,
# used for all future transactions. For MSSQL, this should be set
# to something if you ever plan to use the :isolation option to
# Database#transaction, as on MSSQL if affects all future transactions
# on the same connection.
attr_accessor :transaction_isolation_level
# Starts a database transaction. When a database transaction is used,
# either all statements are successful or none of the statements are
# successful. Note that MySQL MyISAM tables do not support transactions.
#
# The following general options are respected:
#
# :isolation :: The transaction isolation level to use for this transaction,
# should be :uncommitted, :committed, :repeatable, or :serializable,
# used if given and the database/adapter supports customizable
# transaction isolation levels.
# :num_retries :: The number of times to retry if the :retry_on option is used.
# The default is 5 times. Can be set to nil to retry indefinitely,
# but that is not recommended.
# :prepare :: A string to use as the transaction identifier for a
# prepared transaction (two-phase commit), if the database/adapter
# supports prepared transactions.
# :retry_on :: An exception class or array of exception classes for which to
# automatically retry the transaction. Can only be set if not inside
# an existing transaction.
# Note that this should not be used unless the entire transaction
# block is idempotent, as otherwise it can cause non-idempotent
# behavior to execute multiple times.
# :rollback :: Can the set to :reraise to reraise any Sequel::Rollback exceptions
# raised, or :always to always rollback even if no exceptions occur
# (useful for testing).
# :server :: The server to use for the transaction.
# :savepoint :: Whether to create a new savepoint for this transaction,
# only respected if the database/adapter supports savepoints. By
# default Sequel will reuse an existing transaction, so if you want to
# use a savepoint you must use this option.
#
# PostgreSQL specific options:
#
# :deferrable :: (9.1+) If present, set to DEFERRABLE if true or NOT DEFERRABLE if false.
# :read_only :: If present, set to READ ONLY if true or READ WRITE if false.
# :synchronous :: if non-nil, set synchronous_commit
# appropriately. Valid values true, :on, false, :off, :local (9.1+),
# and :remote_write (9.2+).
def transaction(opts=OPTS, &block)
if retry_on = opts[:retry_on]
num_retries = opts.fetch(:num_retries, 5)
begin
transaction(opts.merge(:retry_on=>nil, :retrying=>true), &block)
rescue *retry_on
if num_retries
num_retries -= 1
retry if num_retries >= 0
else
retry
end
raise
end
else
synchronize(opts[:server]) do |conn|
if already_in_transaction?(conn, opts)
if opts[:retrying]
raise Sequel::Error, "cannot set :retry_on options if you are already inside a transaction"
end
return yield(conn)
end
_transaction(conn, opts, &block)
end
end
end
private
# Internal generic transaction method. Any exception raised by the given
# block will cause the transaction to be rolled back. If the exception is
# not a Sequel::Rollback, the error will be reraised. If no exception occurs
# inside the block, the transaction is commited.
def _transaction(conn, opts=OPTS)
rollback = opts[:rollback]
begin
add_transaction(conn, opts)
begin_transaction(conn, opts)
if rollback == :always
begin
yield(conn)
rescue Exception => e1
raise e1
ensure
raise ::Sequel::Rollback unless e1
end
else
yield(conn)
end
rescue Exception => e
begin
rollback_transaction(conn, opts)
rescue Exception => e3
raise_error(e3, :classes=>database_error_classes, :conn=>conn)
end
transaction_error(e, :conn=>conn, :rollback=>rollback)
ensure
begin
committed = commit_or_rollback_transaction(e, conn, opts)
rescue Exception => e2
begin
raise_error(e2, :classes=>database_error_classes, :conn=>conn)
rescue Sequel::DatabaseError => e4
begin
rollback_transaction(conn, opts)
ensure
raise e4
end
end
ensure
remove_transaction(conn, committed)
end
end
end
# Synchronize access to the current transactions, returning the hash
# of options for the current transaction (if any)
def _trans(conn)
Sequel.synchronize{@transactions[conn]}
end
# Add the current thread to the list of active transactions
def add_transaction(conn, opts)
if supports_savepoints?
unless _trans(conn)
if (prep = opts[:prepare]) && supports_prepared_transactions?
Sequel.synchronize{@transactions[conn] = {:savepoint_level=>0, :prepare=>prep}}
else
Sequel.synchronize{@transactions[conn] = {:savepoint_level=>0}}
end
end
elsif (prep = opts[:prepare]) && supports_prepared_transactions?
Sequel.synchronize{@transactions[conn] = {:prepare => prep}}
else
Sequel.synchronize{@transactions[conn] = {}}
end
end
# Call all stored after_commit blocks for the given transaction
def after_transaction_commit(conn)
if ary = _trans(conn)[:after_commit]
ary.each{|b| b.call}
end
end
# Call all stored after_rollback blocks for the given transaction
def after_transaction_rollback(conn)
if ary = _trans(conn)[:after_rollback]
ary.each{|b| b.call}
end
end
# Whether the current thread/connection is already inside a transaction
def already_in_transaction?(conn, opts)
_trans(conn) && (!supports_savepoints? || !opts[:savepoint])
end
# SQL to start a new savepoint
def begin_savepoint_sql(depth)
SQL_SAVEPOINT % depth
end
# Start a new database connection on the given connection
def begin_new_transaction(conn, opts)
log_connection_execute(conn, begin_transaction_sql)
set_transaction_isolation(conn, opts)
end
# Start a new database transaction or a new savepoint on the given connection.
def begin_transaction(conn, opts=OPTS)
if supports_savepoints?
th = _trans(conn)
if (depth = th[:savepoint_level]) > 0
log_connection_execute(conn, begin_savepoint_sql(depth))
else
begin_new_transaction(conn, opts)
end
th[:savepoint_level] += 1
else
begin_new_transaction(conn, opts)
end
end
# SQL to BEGIN a transaction.
def begin_transaction_sql
SQL_BEGIN
end
if (! defined?(RUBY_ENGINE) or RUBY_ENGINE == 'ruby' or RUBY_ENGINE == 'rbx') and RUBY_VERSION < '1.9'
# :nocov:
# Whether to commit the current transaction. On ruby 1.8 and rubinius,
# Thread.current.status is checked because Thread#kill skips rescue
# blocks (so exception would be nil), but the transaction should
# still be rolled back.
def commit_or_rollback_transaction(exception, conn, opts)
if exception
false
else
if Thread.current.status == 'aborting'
rollback_transaction(conn, opts)
false
else
commit_transaction(conn, opts)
true
end
end
end
# :nocov:
else
# Whether to commit the current transaction. On ruby 1.9 and JRuby,
# transactions will be committed if Thread#kill is used on an thread
# that has a transaction open, and there isn't a work around.
def commit_or_rollback_transaction(exception, conn, opts)
if exception
false
else
commit_transaction(conn, opts)
true
end
end
end
# SQL to commit a savepoint
def commit_savepoint_sql(depth)
SQL_RELEASE_SAVEPOINT % depth
end
# Commit the active transaction on the connection
def commit_transaction(conn, opts=OPTS)
if supports_savepoints?
depth = _trans(conn)[:savepoint_level]
log_connection_execute(conn, depth > 1 ? commit_savepoint_sql(depth-1) : commit_transaction_sql)
else
log_connection_execute(conn, commit_transaction_sql)
end
end
# SQL to COMMIT a transaction.
def commit_transaction_sql
SQL_COMMIT
end
# Method called on the connection object to execute SQL on the database,
# used by the transaction code.
def connection_execute_method
:execute
end
# Remove the current thread from the list of active transactions
def remove_transaction(conn, committed)
if !supports_savepoints? || ((_trans(conn)[:savepoint_level] -= 1) <= 0)
begin
if committed
after_transaction_commit(conn)
else
after_transaction_rollback(conn)
end
ensure
Sequel.synchronize{@transactions.delete(conn)}
end
end
end
# SQL to rollback to a savepoint
def rollback_savepoint_sql(depth)
SQL_ROLLBACK_TO_SAVEPOINT % depth
end
# Rollback the active transaction on the connection
def rollback_transaction(conn, opts=OPTS)
if supports_savepoints?
depth = _trans(conn)[:savepoint_level]
log_connection_execute(conn, depth > 1 ? rollback_savepoint_sql(depth-1) : rollback_transaction_sql)
else
log_connection_execute(conn, rollback_transaction_sql)
end
end
# SQL to ROLLBACK a transaction.
def rollback_transaction_sql
SQL_ROLLBACK
end
# Set the transaction isolation level on the given connection
def set_transaction_isolation(conn, opts)
if supports_transaction_isolation_levels? and level = opts.fetch(:isolation, transaction_isolation_level)
log_connection_execute(conn, set_transaction_isolation_sql(level))
end
end
# SQL to set the transaction isolation level
def set_transaction_isolation_sql(level)
"SET TRANSACTION ISOLATION LEVEL #{TRANSACTION_ISOLATION_LEVELS[level]}"
end
# Raise a database error unless the exception is an Rollback.
def transaction_error(e, opts=OPTS)
if e.is_a?(Rollback)
raise e if opts[:rollback] == :reraise
else
raise_error(e, opts.merge(:classes=>database_error_classes))
end
end
end
end
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