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module ActiveRecord
class Base
class ConnectionSpecification #:nodoc:
attr_reader :config, :adapter_method
def initialize (config, adapter_method)
@config, @adapter_method = config, adapter_method
end
end
# Check for activity after at least +verification_timeout+ seconds.
# Defaults to 0 (always check.)
cattr_accessor :verification_timeout, :instance_writer => false
@@verification_timeout = 0
# The connection handler
cattr_accessor :connection_handler, :instance_writer => false
@@connection_handler = ConnectionAdapters::SingleThreadConnectionHandler.new
# Turning on allow_concurrency changes the single threaded connection handler
# for a multiple threaded one, so that multi-threaded access of the
# connection pools is synchronized.
def self.allow_concurrency=(flag)
if @@allow_concurrency != flag
@@allow_concurrency = flag
# When switching connection handlers, preserve the existing pools so that
# #establish_connection doesn't need to be called again.
if @@allow_concurrency
self.connection_handler = ConnectionAdapters::MultipleThreadConnectionHandler.new(
self.connection_handler.connection_pools)
else
self.connection_handler = ConnectionAdapters::SingleThreadConnectionHandler.new(
self.connection_handler.connection_pools)
end
end
end
# Returns the connection currently associated with the class. This can
# also be used to "borrow" the connection to do database work that isn't
# easily done without going straight to SQL.
def connection
self.class.connection
end
# Establishes the connection to the database. Accepts a hash as input where
# the <tt>:adapter</tt> key must be specified with the name of a database adapter (in lower-case)
# example for regular databases (MySQL, Postgresql, etc):
#
# ActiveRecord::Base.establish_connection(
# :adapter => "mysql",
# :host => "localhost",
# :username => "myuser",
# :password => "mypass",
# :database => "somedatabase"
# )
#
# Example for SQLite database:
#
# ActiveRecord::Base.establish_connection(
# :adapter => "sqlite",
# :database => "path/to/dbfile"
# )
#
# Also accepts keys as strings (for parsing from YAML for example):
#
# ActiveRecord::Base.establish_connection(
# "adapter" => "sqlite",
# "database" => "path/to/dbfile"
# )
#
# The exceptions AdapterNotSpecified, AdapterNotFound and ArgumentError
# may be returned on an error.
def self.establish_connection(spec = nil)
case spec
when nil
raise AdapterNotSpecified unless defined? RAILS_ENV
establish_connection(RAILS_ENV)
when ConnectionSpecification
@@connection_handler.establish_connection(name, spec)
when Symbol, String
if configuration = configurations[spec.to_s]
establish_connection(configuration)
else
raise AdapterNotSpecified, "#{spec} database is not configured"
end
else
spec = spec.symbolize_keys
unless spec.key?(:adapter) then raise AdapterNotSpecified, "database configuration does not specify adapter" end
begin
require 'rubygems'
gem "activerecord-#{spec[:adapter]}-adapter"
require "active_record/connection_adapters/#{spec[:adapter]}_adapter"
rescue LoadError
begin
require "active_record/connection_adapters/#{spec[:adapter]}_adapter"
rescue LoadError
raise "Please install the #{spec[:adapter]} adapter: `gem install activerecord-#{spec[:adapter]}-adapter` (#{$!})"
end
end
adapter_method = "#{spec[:adapter]}_connection"
if !respond_to?(adapter_method)
raise AdapterNotFound, "database configuration specifies nonexistent #{spec[:adapter]} adapter"
end
remove_connection
establish_connection(ConnectionSpecification.new(spec, adapter_method))
end
end
class << self
# Returns the connection currently associated with the class. This can
# also be used to "borrow" the connection to do database work unrelated
# to any of the specific Active Records.
def connection
retrieve_connection
end
def connection_pool
connection_handler.retrieve_connection_pool(self)
end
def retrieve_connection
connection_handler.retrieve_connection(self)
end
def connected?
connection_handler.connected?(self)
end
def remove_connection(klass = self)
connection_handler.remove_connection(klass)
end
delegate :active_connections, :clear_active_connections!,
:clear_reloadable_connections!, :clear_all_connections!,
:verify_active_connections!, :to => :connection_handler
end
end
end
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