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abstract_adapter.rb
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abstract_adapter.rb
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require 'benchmark'
require 'date'
# Method that requires a library, ensuring that rubygems is loaded
# This is used in the database adaptors to require DB drivers. Reasons:
# (1) database drivers are the only third-party library that Rails depend upon
# (2) they are often installed as gems
def require_library_or_gem(library_name)
begin
require library_name
rescue LoadError => cannot_require
# 1. Requiring the module is unsuccessful, maybe it's a gem and nobody required rubygems yet. Try.
begin
require 'rubygems'
rescue LoadError => rubygems_not_installed
raise cannot_require
end
# 2. Rubygems is installed and loaded. Try to load the library again
begin
require library_name
rescue LoadError => gem_not_installed
raise cannot_require
end
end
end
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
# The class -> [adapter_method, config] map
@@defined_connections = {}
# Establishes the connection to the database. Accepts a hash as input where
# the :adapter 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",
# :dbfile => "path/to/dbfile"
# )
#
# Also accepts keys as strings (for parsing from yaml for example):
# ActiveRecord::Base.establish_connection(
# "adapter" => "sqlite",
# "dbfile" => "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
@@defined_connections[self] = 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
adapter_method = "#{spec[:adapter]}_connection"
unless respond_to?(adapter_method) then raise AdapterNotFound, "database configuration specifies nonexistent #{spec[:adapter]} adapter" end
remove_connection
establish_connection(ConnectionSpecification.new(spec, adapter_method))
end
end
def self.active_connections #:nodoc:
if threaded_connections
Thread.current['active_connections'] ||= {}
else
@@active_connections ||= {}
end
end
# Locate the connection of the nearest super class. This can be an
# active or defined connections: if it is the latter, it will be
# opened and set as the active connection for the class it was defined
# for (not necessarily the current class).
def self.retrieve_connection #:nodoc:
klass = self
ar_super = ActiveRecord::Base.superclass
until klass == ar_super
if conn = active_connections[klass]
return conn
elsif conn = @@defined_connections[klass]
klass.connection = conn
return self.connection
end
klass = klass.superclass
end
raise ConnectionNotEstablished
end
# Returns true if a connection that's accessible to this class have already been opened.
def self.connected?
klass = self
until klass == ActiveRecord::Base.superclass
if active_connections[klass]
return true
else
klass = klass.superclass
end
end
return false
end
# Remove the connection for this class. This will close the active
# connection and the defined connection (if they exist). The result
# can be used as argument for establish_connection, for easy
# re-establishing of the connection.
def self.remove_connection(klass=self)
conn = @@defined_connections[klass]
@@defined_connections.delete(klass)
active_connections[klass] = nil
conn.config if conn
end
# Set the connection for the class.
def self.connection=(spec)
raise ConnectionNotEstablished unless spec
conn = self.send(spec.adapter_method, spec.config)
active_connections[self] = conn
end
# Converts all strings in a hash to symbols.
def self.symbolize_strings_in_hash(hash) #:nodoc:
hash.symbolize_keys
end
end
module ConnectionAdapters # :nodoc:
class Column # :nodoc:
attr_reader :name, :default, :type, :limit
# The name should contain the name of the column, such as "name" in "name varchar(250)"
# The default should contain the type-casted default of the column, such as 1 in "count int(11) DEFAULT 1"
# The type parameter should either contain :integer, :float, :datetime, :date, :text, or :string
# The sql_type is just used for extracting the limit, such as 10 in "varchar(10)"
def initialize(name, default, sql_type = nil)
@name, @default, @type = name, type_cast(default), simplified_type(sql_type)
@limit = extract_limit(sql_type) unless sql_type.nil?
end
def klass
case type
when :integer then Fixnum
when :float then Float
when :datetime then Time
when :date then Date
when :timestamp then Time
when :time then Time
when :text, :string then String
when :binary then String
when :boolean then Object
end
end
def type_cast(value)
if value.nil? then return nil end
case type
when :string then value
when :text then value
when :integer then value.to_i rescue value ? 1 : 0
when :float then value.to_f
when :datetime then string_to_time(value)
when :timestamp then string_to_time(value)
when :time then string_to_dummy_time(value)
when :date then string_to_date(value)
when :binary then binary_to_string(value)
when :boolean then value == true or (value =~ /^t(rue)?$/i) == 0 or value.to_s == '1'
else value
end
end
def human_name
Base.human_attribute_name(@name)
end
def string_to_binary(value)
value
end
def binary_to_string(value)
value
end
private
def string_to_date(string)
return string unless string.is_a?(String)
date_array = ParseDate.parsedate(string.to_s)
# treat 0000-00-00 as nil
Date.new(date_array[0], date_array[1], date_array[2]) rescue nil
end
def string_to_time(string)
return string unless string.is_a?(String)
time_array = ParseDate.parsedate(string.to_s).compact
# treat 0000-00-00 00:00:00 as nil
Time.send(Base.default_timezone, *time_array) rescue nil
end
def string_to_dummy_time(string)
return string unless string.is_a?(String)
time_array = ParseDate.parsedate(string.to_s)
# pad the resulting array with dummy date information
time_array[0] = 2000; time_array[1] = 1; time_array[2] = 1;
Time.send(Base.default_timezone, *time_array) rescue nil
end
def extract_limit(sql_type)
$1.to_i if sql_type =~ /\((.*)\)/
end
def simplified_type(field_type)
case field_type
when /int/i
:integer
when /float|double|decimal|numeric/i
:float
when /datetime/i
:datetime
when /timestamp/i
:timestamp
when /time/i
:time
when /date/i
:date
when /clob/i, /text/i
:text
when /blob/i, /binary/i
:binary
when /char/i, /string/i
:string
when /boolean/i
:boolean
end
end
end
# All the concrete database adapters follow the interface laid down in this class.
# You can use this interface directly by borrowing the database connection from the Base with
# Base.connection.
class AbstractAdapter
@@row_even = true
def initialize(connection, logger = nil) # :nodoc:
@connection, @logger = connection, logger
@runtime = 0
end
# Returns an array of record hashes with the column names as a keys and fields as values.
def select_all(sql, name = nil) end
# Returns a record hash with the column names as a keys and fields as values.
def select_one(sql, name = nil) end
# Returns an array of column objects for the table specified by +table_name+.
def columns(table_name, name = nil) end
# Returns the last auto-generated ID from the affected table.
def insert(sql, name = nil, pk = nil, id_value = nil, sequence_name = nil) end
# Executes the update statement and returns the number of rows affected.
def update(sql, name = nil) end
# Executes the delete statement and returns the number of rows affected.
def delete(sql, name = nil) end
def reset_runtime # :nodoc:
rt = @runtime
@runtime = 0
return rt
end
# Wrap a block in a transaction. Returns result of block.
def transaction(start_db_transaction = true)
begin
if block_given?
begin_db_transaction if start_db_transaction
result = yield
commit_db_transaction if start_db_transaction
result
end
rescue Exception => database_transaction_rollback
rollback_db_transaction if start_db_transaction
raise
end
end
# Begins the transaction (and turns off auto-committing).
def begin_db_transaction() end
# Commits the transaction (and turns on auto-committing).
def commit_db_transaction() end
# Rolls back the transaction (and turns on auto-committing). Must be done if the transaction block
# raises an exception or returns false.
def rollback_db_transaction() end
def quote(value, column = nil)
case value
when String
if column && column.type == :binary
"'#{quote_string(column.string_to_binary(value))}'" # ' (for ruby-mode)
elsif column && [:integer, :float].include?(column.type)
value.to_s
else
"'#{quote_string(value)}'" # ' (for ruby-mode)
end
when NilClass then "NULL"
when TrueClass then (column && column.type == :boolean ? "'t'" : "1")
when FalseClass then (column && column.type == :boolean ? "'f'" : "0")
when Float, Fixnum, Bignum then value.to_s
when Date then "'#{value.to_s}'"
when Time, DateTime then "'#{value.strftime("%Y-%m-%d %H:%M:%S")}'"
else "'#{quote_string(value.to_yaml)}'"
end
end
def quote_string(s)
s.gsub(/\\/, '\&\&').gsub(/'/, "''") # ' (for ruby-mode)
end
def quote_column_name(name)
name
end
# Returns the human-readable name of the adapter. Use mixed case - one can always use downcase if needed.
def adapter_name()
'Abstract'
end
# Returns a string of the CREATE TABLE SQL statements for recreating the entire structure of the database.
def structure_dump() end
def add_limit!(sql, options)
return unless options
add_limit_offset!(sql, options)
end
def add_limit_offset!(sql, options)
return if options[:limit].nil?
sql << " LIMIT #{options[:limit]}"
sql << " OFFSET #{options[:offset]}" if options.has_key?(:offset) and !options[:offset].nil?
end
def initialize_schema_information
begin
execute "CREATE TABLE schema_info (version #{type_to_sql(:integer)})"
execute "INSERT INTO schema_info (version) VALUES(0)"
rescue ActiveRecord::StatementInvalid
# Schema has been intialized
end
end
def create_table(name, options = {})
table_definition = TableDefinition.new(self)
table_definition.primary_key(options[:primary_key] || "id") unless options[:id] == false
yield table_definition
create_sql = "CREATE#{' TEMPORARY' if options[:temporary]} TABLE "
create_sql << "#{name} ("
create_sql << table_definition.to_sql
create_sql << ") #{options[:options]}"
execute create_sql
end
def drop_table(name)
execute "DROP TABLE #{name}"
end
def add_column(table_name, column_name, type, options = {})
native_type = native_database_types[type]
add_column_sql = "ALTER TABLE #{table_name} ADD #{column_name} #{type_to_sql(type, options[:limit])}"
add_column_options!(add_column_sql, options)
execute(add_column_sql)
end
def remove_column(table_name, column_name)
execute "ALTER TABLE #{table_name} DROP #{column_name}"
end
def change_column(table_name, column_name, type, options = {})
raise NotImplementedError, "change_column is not implemented"
end
def change_column_default(table_name, column_name, default)
raise NotImplementedError, "change_column_default is not implemented"
end
def rename_column(table_name, column_name, new_column_name)
raise NotImplementedError, "rename_column is not implemented"
end
def add_index(table_name, column_name, index_type = '')
execute "CREATE #{index_type} INDEX #{table_name}_#{column_name.to_a.first}_index ON #{table_name} (#{column_name.to_a.join(", ")})"
end
def remove_index(table_name, column_name)
execute "DROP INDEX #{table_name}_#{column_name}_index ON #{table_name}"
end
def supports_migrations?
false
end
def native_database_types
{}
end
def type_to_sql(type, limit = nil)
native = native_database_types[type]
limit ||= native[:limit]
column_type_sql = native[:name]
column_type_sql << "(#{limit})" if limit
column_type_sql
end
def add_column_options!(sql, options)
sql << " NOT NULL" if options[:null] == false
sql << " DEFAULT '#{options[:default]}'" unless options[:default].nil?
end
protected
def log(sql, name)
begin
if block_given?
if @logger and @logger.level <= Logger::INFO
result = nil
seconds = Benchmark.realtime { result = yield }
@runtime += seconds
log_info(sql, name, seconds)
result
else
yield
end
else
log_info(sql, name, 0)
nil
end
rescue Exception => e
log_info("#{e.message}: #{sql}", name, 0)
raise ActiveRecord::StatementInvalid, "#{e.message}: #{sql}"
end
end
def log_info(sql, name, runtime)
return unless @logger
@logger.debug(
format_log_entry(
"#{name.nil? ? "SQL" : name} (#{sprintf("%f", runtime)})",
sql.gsub(/ +/, " ")
)
)
end
def format_log_entry(message, dump = nil)
if ActiveRecord::Base.colorize_logging
if @@row_even then
@@row_even = false; caller_color = "1;32"; message_color = "4;33"; dump_color = "1;37"
else
@@row_even = true; caller_color = "1;36"; message_color = "4;35"; dump_color = "0;37"
end
log_entry = " \e[#{message_color}m#{message}\e[m"
log_entry << " \e[#{dump_color}m%s\e[m" % dump if dump.kind_of?(String) && !dump.nil?
log_entry << " \e[#{dump_color}m%p\e[m" % dump if !dump.kind_of?(String) && !dump.nil?
log_entry
else
"%s %s" % [message, dump]
end
end
end
class ColumnDefinition < Struct.new(:base, :name, :type, :limit, :default, :null)
def to_sql
column_sql = "#{name} #{type_to_sql(type.to_sym, limit)}"
add_column_options!(column_sql, :null => null, :default => default)
column_sql
end
alias to_s :to_sql
private
def type_to_sql(name, limit)
base.type_to_sql(name, limit) rescue name
end
def add_column_options!(sql, options)
base.add_column_options!(sql, options)
end
end
class TableDefinition
attr_accessor :columns
def initialize(base)
@columns = []
@base = base
end
def primary_key(name)
column(name, native[:primary_key])
end
def [](name)
@columns.find {|column| column.name == name}
end
def column(name, type, options = {})
column = self[name] || ColumnDefinition.new(@base, name, type)
column.limit = options[:limit] || native[type.to_sym][:limit] if options[:limit] or native[type.to_sym]
column.default = options[:default]
column.null = options[:null]
@columns << column unless @columns.include? column
self
end
def to_sql
@columns * ', '
end
private
def native
@base.native_database_types
end
end
end
end