r4663@asus: jeremy | 2006-06-19 17:23:57 -0700
ActiveRecord::Locking is now ActiveRecord::Locking::Optimistic (to make way for Pessimistic.) git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@4461 5ecf4fe2-1ee6-0310-87b1-e25e094e27de
This commit is contained in:
parent
15aa6e0552
commit
e4254939aa
|
@ -54,7 +54,7 @@ require 'active_record/xml_serialization'
|
||||||
|
|
||||||
ActiveRecord::Base.class_eval do
|
ActiveRecord::Base.class_eval do
|
||||||
include ActiveRecord::Validations
|
include ActiveRecord::Validations
|
||||||
include ActiveRecord::Locking
|
include ActiveRecord::Locking::Optimistic
|
||||||
include ActiveRecord::Callbacks
|
include ActiveRecord::Callbacks
|
||||||
include ActiveRecord::Observing
|
include ActiveRecord::Observing
|
||||||
include ActiveRecord::Timestamp
|
include ActiveRecord::Timestamp
|
||||||
|
|
|
@ -1,77 +1,84 @@
|
||||||
module ActiveRecord
|
module ActiveRecord
|
||||||
# Active Records support optimistic locking if the field <tt>lock_version</tt> is present. Each update to the
|
|
||||||
# record increments the lock_version column and the locking facilities ensure that records instantiated twice
|
|
||||||
# will let the last one saved raise a StaleObjectError if the first was also updated. Example:
|
|
||||||
#
|
|
||||||
# p1 = Person.find(1)
|
|
||||||
# p2 = Person.find(1)
|
|
||||||
#
|
|
||||||
# p1.first_name = "Michael"
|
|
||||||
# p1.save
|
|
||||||
#
|
|
||||||
# p2.first_name = "should fail"
|
|
||||||
# p2.save # Raises a ActiveRecord::StaleObjectError
|
|
||||||
#
|
|
||||||
# You're then responsible for dealing with the conflict by rescuing the exception and either rolling back, merging,
|
|
||||||
# or otherwise apply the business logic needed to resolve the conflict.
|
|
||||||
#
|
|
||||||
# You must ensure that your database schema defaults the lock_version column to 0.
|
|
||||||
#
|
|
||||||
# This behavior can be turned off by setting <tt>ActiveRecord::Base.lock_optimistically = false</tt>.
|
|
||||||
# To override the name of the lock_version column, invoke the <tt>set_locking_column</tt> method.
|
|
||||||
# This method uses the same syntax as <tt>set_table_name</tt>
|
|
||||||
module Locking
|
module Locking
|
||||||
def self.included(base) #:nodoc:
|
# Active Records support optimistic locking if the field <tt>lock_version</tt> is present. Each update to the
|
||||||
base.class_eval do
|
# record increments the lock_version column and the locking facilities ensure that records instantiated twice
|
||||||
alias_method_chain :update, :lock
|
# will let the last one saved raise a StaleObjectError if the first was also updated. Example:
|
||||||
|
#
|
||||||
|
# p1 = Person.find(1)
|
||||||
|
# p2 = Person.find(1)
|
||||||
|
#
|
||||||
|
# p1.first_name = "Michael"
|
||||||
|
# p1.save
|
||||||
|
#
|
||||||
|
# p2.first_name = "should fail"
|
||||||
|
# p2.save # Raises a ActiveRecord::StaleObjectError
|
||||||
|
#
|
||||||
|
# You're then responsible for dealing with the conflict by rescuing the exception and either rolling back, merging,
|
||||||
|
# or otherwise apply the business logic needed to resolve the conflict.
|
||||||
|
#
|
||||||
|
# You must ensure that your database schema defaults the lock_version column to 0.
|
||||||
|
#
|
||||||
|
# This behavior can be turned off by setting <tt>ActiveRecord::Base.lock_optimistically = false</tt>.
|
||||||
|
# To override the name of the lock_version column, invoke the <tt>set_locking_column</tt> method.
|
||||||
|
# This method uses the same syntax as <tt>set_table_name</tt>
|
||||||
|
module Optimistic
|
||||||
|
def self.included(base) #:nodoc:
|
||||||
|
super
|
||||||
|
base.extend ClassMethods
|
||||||
|
|
||||||
|
base.cattr_accessor :lock_optimistically
|
||||||
|
base.lock_optimistically = true
|
||||||
|
|
||||||
|
base.alias_method_chain :update, :lock
|
||||||
|
class << base
|
||||||
|
alias_method :locking_column=, :set_locking_column
|
||||||
|
end
|
||||||
|
end
|
||||||
|
|
||||||
|
def locking_enabled? #:nodoc:
|
||||||
|
lock_optimistically && respond_to?(self.class.locking_column)
|
||||||
|
end
|
||||||
|
|
||||||
|
def update_with_lock #:nodoc:
|
||||||
|
return update_without_lock unless locking_enabled?
|
||||||
|
|
||||||
|
lock_col = self.class.locking_column
|
||||||
|
previous_value = send(lock_col)
|
||||||
|
send(lock_col + '=', previous_value + 1)
|
||||||
|
|
||||||
|
affected_rows = connection.update(<<-end_sql, "#{self.class.name} Update with optimistic locking")
|
||||||
|
UPDATE #{self.class.table_name}
|
||||||
|
SET #{quoted_comma_pair_list(connection, attributes_with_quotes(false))}
|
||||||
|
WHERE #{self.class.primary_key} = #{quote(id)}
|
||||||
|
AND #{lock_col} = #{quote(previous_value)}
|
||||||
|
end_sql
|
||||||
|
|
||||||
|
unless affected_rows == 1
|
||||||
|
raise ActiveRecord::StaleObjectError, "Attempted to update a stale object"
|
||||||
|
end
|
||||||
|
|
||||||
|
return true
|
||||||
|
end
|
||||||
|
|
||||||
|
module ClassMethods
|
||||||
|
DEFAULT_LOCKING_COLUMN = 'lock_version'
|
||||||
|
|
||||||
|
# Set the column to use for optimistic locking. Defaults to lock_version.
|
||||||
|
def set_locking_column(value = nil, &block)
|
||||||
|
define_attr_method :locking_column, value, &block
|
||||||
|
value
|
||||||
|
end
|
||||||
|
|
||||||
|
# The version column used for optimistic locking. Defaults to lock_version.
|
||||||
|
def locking_column
|
||||||
|
reset_locking_column
|
||||||
|
end
|
||||||
|
|
||||||
|
# Reset the column used for optimistic locking back to the lock_version default.
|
||||||
|
def reset_locking_column
|
||||||
|
set_locking_column DEFAULT_LOCKING_COLUMN
|
||||||
|
end
|
||||||
end
|
end
|
||||||
end
|
end
|
||||||
|
|
||||||
def update_with_lock #:nodoc:
|
|
||||||
return update_without_lock unless locking_enabled?
|
|
||||||
|
|
||||||
lock_col = self.class.locking_column
|
|
||||||
previous_value = send(lock_col)
|
|
||||||
send(lock_col + '=', previous_value + 1)
|
|
||||||
|
|
||||||
affected_rows = connection.update(<<-end_sql, "#{self.class.name} Update with optimistic locking")
|
|
||||||
UPDATE #{self.class.table_name}
|
|
||||||
SET #{quoted_comma_pair_list(connection, attributes_with_quotes(false))}
|
|
||||||
WHERE #{self.class.primary_key} = #{quote(id)}
|
|
||||||
AND #{lock_col} = #{quote(previous_value)}
|
|
||||||
end_sql
|
|
||||||
|
|
||||||
unless affected_rows == 1
|
|
||||||
raise ActiveRecord::StaleObjectError, "Attempted to update a stale object"
|
|
||||||
end
|
|
||||||
|
|
||||||
return true
|
|
||||||
end
|
|
||||||
end
|
|
||||||
|
|
||||||
class Base
|
|
||||||
@@lock_optimistically = true
|
|
||||||
cattr_accessor :lock_optimistically
|
|
||||||
|
|
||||||
def locking_enabled? #:nodoc:
|
|
||||||
lock_optimistically && respond_to?(self.class.locking_column)
|
|
||||||
end
|
|
||||||
|
|
||||||
class << self
|
|
||||||
def set_locking_column(value = nil, &block)
|
|
||||||
define_attr_method :locking_column, value, &block
|
|
||||||
end
|
|
||||||
|
|
||||||
def locking_column #:nodoc:
|
|
||||||
reset_locking_column
|
|
||||||
end
|
|
||||||
|
|
||||||
def reset_locking_column #:nodoc:
|
|
||||||
default = 'lock_version'
|
|
||||||
set_locking_column(default)
|
|
||||||
default
|
|
||||||
end
|
|
||||||
end
|
|
||||||
|
|
||||||
end
|
end
|
||||||
end
|
end
|
||||||
|
|
Loading…
Reference in New Issue