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|
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
def enable_query_cache!
@query_cache_enabled = true
end
def disable_query_cache!
@query_cache_enabled = false
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(arel, name = nil, binds = [])
if @query_cache_enabled
sql = to_sql(arel, binds)
cache_sql(sql, binds) { super(sql, name, binds) }
else
super
end
end
private
def cache_sql(sql, binds)
result =
if @query_cache[sql].key?(binds)
ActiveSupport::Notifications.instrument("sql.active_record",
:sql => sql, :binds => binds, :name => "CACHE", :connection_id => object_id)
@query_cache[sql][binds]
else
@query_cache[sql][binds] = yield
end
# FIXME: we should guarantee that all cached items are Result
# objects. Then we can avoid this conditional
if ActiveRecord::Result === result
result.dup
else
result.collect { |row| row.dup }
end
end
end
end
end
|
