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author | Emilio Tagua <miloops@gmail.com> | 2009-12-27 18:04:35 -0300 |
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committer | Emilio Tagua <miloops@gmail.com> | 2009-12-27 18:04:35 -0300 |
commit | b339caca2f3c7306c3944c5fc5d8dde17ae2deb8 (patch) | |
tree | a443bebb38ffc34c3642a655c5cc9d20a22ee3d3 | |
parent | 3ea68bc6bde539f4391cc1b96999e16c25ca0801 (diff) | |
download | rails-b339caca2f3c7306c3944c5fc5d8dde17ae2deb8.tar.gz rails-b339caca2f3c7306c3944c5fc5d8dde17ae2deb8.tar.bz2 rails-b339caca2f3c7306c3944c5fc5d8dde17ae2deb8.zip |
Added lock to Arel, allowing a locking read if required.
-rw-r--r-- | lib/arel/algebra/relations.rb | 1 | ||||
-rw-r--r-- | lib/arel/algebra/relations/operations/lock.rb | 12 | ||||
-rw-r--r-- | lib/arel/algebra/relations/relation.rb | 5 | ||||
-rw-r--r-- | lib/arel/algebra/relations/utilities/compound.rb | 2 | ||||
-rw-r--r-- | lib/arel/engines/sql/relations/relation.rb | 6 | ||||
-rw-r--r-- | spec/arel/engines/sql/unit/relations/lock_spec.rb | 47 |
6 files changed, 70 insertions, 3 deletions
diff --git a/lib/arel/algebra/relations.rb b/lib/arel/algebra/relations.rb index cee308299b..951b69d970 100644 --- a/lib/arel/algebra/relations.rb +++ b/lib/arel/algebra/relations.rb @@ -13,3 +13,4 @@ require 'arel/algebra/relations/operations/project' require 'arel/algebra/relations/operations/where' require 'arel/algebra/relations/operations/skip' require 'arel/algebra/relations/operations/take' +require 'arel/algebra/relations/operations/lock' diff --git a/lib/arel/algebra/relations/operations/lock.rb b/lib/arel/algebra/relations/operations/lock.rb new file mode 100644 index 0000000000..0d6c12e65b --- /dev/null +++ b/lib/arel/algebra/relations/operations/lock.rb @@ -0,0 +1,12 @@ +module Arel + class Lock < Compound + attributes :relation, :locked + deriving :initialize, :== + + def initialize(relation, locked, &block) + @relation = relation + @locked = locked.blank? ? " FOR UPDATE" : locked + end + end +end + diff --git a/lib/arel/algebra/relations/relation.rb b/lib/arel/algebra/relations/relation.rb index 2ce3fdcce8..b24e7c24d0 100644 --- a/lib/arel/algebra/relations/relation.rb +++ b/lib/arel/algebra/relations/relation.rb @@ -51,6 +51,10 @@ module Arel OPERATION end + def lock(locking = nil) + Lock.new(self, locking) + end + def alias Alias.new(self) end @@ -131,6 +135,7 @@ module Arel def taken; nil end def skipped; nil end def sources; [] end + def locked; [] end end include DefaultOperations end diff --git a/lib/arel/algebra/relations/utilities/compound.rb b/lib/arel/algebra/relations/utilities/compound.rb index 06bfce4ac0..9967472d88 100644 --- a/lib/arel/algebra/relations/utilities/compound.rb +++ b/lib/arel/algebra/relations/utilities/compound.rb @@ -2,7 +2,7 @@ module Arel class Compound < Relation attr_reader :relation delegate :joins, :join?, :inserts, :taken, :skipped, :name, :externalizable?, - :column_for, :engine, :sources, + :column_for, :engine, :sources, :locked, :to => :relation [:attributes, :wheres, :groupings, :orders].each do |operation_name| diff --git a/lib/arel/engines/sql/relations/relation.rb b/lib/arel/engines/sql/relations/relation.rb index 448cf7951d..8b71aa8c04 100644 --- a/lib/arel/engines/sql/relations/relation.rb +++ b/lib/arel/engines/sql/relations/relation.rb @@ -16,7 +16,8 @@ module Arel "FROM #{from_clauses}", (joins(self) unless joins(self).blank? ), ("WHERE #{where_clauses.join("\n\tAND ")}" unless wheres.blank? ), - ("GROUP BY #{group_clauses.join(', ')}" unless groupings.blank? ) + ("GROUP BY #{group_clauses.join(', ')}" unless groupings.blank? ), + ("#{locked}" unless locked.blank? ) build_query \ "SELECT * FROM (#{query}) AS id_list", @@ -33,7 +34,8 @@ module Arel ("GROUP BY #{group_clauses.join(', ')}" unless groupings.blank? ), ("ORDER BY #{order_clauses.join(', ')}" unless orders.blank? ), ("LIMIT #{taken}" unless taken.blank? ), - ("OFFSET #{skipped}" unless skipped.blank? ) + ("OFFSET #{skipped}" unless skipped.blank? ), + ("#{locked}" unless locked.blank? ) end end diff --git a/spec/arel/engines/sql/unit/relations/lock_spec.rb b/spec/arel/engines/sql/unit/relations/lock_spec.rb new file mode 100644 index 0000000000..27239eb1a8 --- /dev/null +++ b/spec/arel/engines/sql/unit/relations/lock_spec.rb @@ -0,0 +1,47 @@ +require 'spec_helper' + +module Arel + describe Lock do + before do + @relation = Table.new(:users) + end + + describe '#to_sql' do + it "manufactures a simple select query lock" do + sql = @relation.lock.to_sql + + adapter_is :mysql do + sql.should be_like(%Q{ + SELECT `users`.`id`, `users`.`name` + FROM `users` FOR UPDATE + }) + end + + adapter_is_not :mysql do + sql.should be_like(%Q{ + SELECT "users"."id", "users"."name" + FROM "users" FOR UPDATE + }) + end + end + + it "manufactures a select query locking with a given lock" do + sql = @relation.lock("LOCK IN SHARE MODE").to_sql + + adapter_is :mysql do + sql.should be_like(%Q{ + SELECT `users`.`id`, `users`.`name` + FROM `users` LOCK IN SHARE MODE + }) + end + + adapter_is_not :mysql do + sql.should be_like(%Q{ + SELECT "users"."id", "users"."name" + FROM "users" LOCK IN SHARE MODE + }) + end + end + end + end +end |