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require 'active_support/core_ext/object/duplicable'
module ActiveRecord
module ConnectionAdapters # :nodoc:
module QueryCache
class << self
def included(base)
dirties_query_cache base, :insert, :update, :delete
end
def dirties_query_cache(base, *method_names)
method_names.each do |method_name|
base.class_eval <<-end_code, __FILE__, __LINE__ + 1
def #{method_name}(*) # def update_with_query_dirty(*args)
clear_query_cache if @query_cache_enabled # clear_query_cache if @query_cache_enabled
super # update_without_query_dirty(*args)
end # end
end_code
end
end
end
attr_reader :query_cache, :query_cache_enabled
# Enable the query cache within the block.
def cache
old, @query_cache_enabled = @query_cache_enabled, true
yield
ensure
clear_query_cache
@query_cache_enabled = old
end
# Disable the query cache within the block.
def uncached
old, @query_cache_enabled = @query_cache_enabled, false
yield
ensure
@query_cache_enabled = old
end
# Clears the query cache.
#
# One reason you may wish to call this method explicitly is between queries
# that ask the database to randomize results. Otherwise the cache would see
# the same SQL query and repeatedly return the same result each time, silently
# undermining the randomness you were expecting.
def clear_query_cache
@query_cache.clear
end
def select_all(*args)
if @query_cache_enabled
cache_sql(args.first) { super }
else
super
end
end
private
def cache_sql(sql)
result =
if @query_cache.has_key?(sql)
ActiveSupport::Notifications.instrument("sql.active_record",
:sql => sql, :name => "CACHE", :connection_id => self.object_id)
@query_cache[sql]
else
@query_cache[sql] = yield
end
if Array === result
result.collect { |row| row.dup }
else
result.duplicable? ? result.dup : result
end
rescue TypeError
result
end
end
end
end
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