aboutsummaryrefslogtreecommitdiffstats
path: root/activerecord/lib/active_record/core.rb
blob: 980f8fe50fe0b9f4e70b9b0931c405378532a49e (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
require 'active_support/concern'

module ActiveRecord
  module Core
    extend ActiveSupport::Concern

    included do
      ##
      # :singleton-method:
      # Accepts a logger conforming to the interface of Log4r or the default Ruby 1.8+ Logger class,
      # which is then passed on to any new database connections made and which can be retrieved on both
      # a class and instance level by calling +logger+.
      config_attribute :logger, :global => true

      ##
      # :singleton-method:
      # Contains the database configuration - as is typically stored in config/database.yml -
      # as a Hash.
      #
      # For example, the following database.yml...
      #
      #   development:
      #     adapter: sqlite3
      #     database: db/development.sqlite3
      #
      #   production:
      #     adapter: sqlite3
      #     database: db/production.sqlite3
      #
      # ...would result in ActiveRecord::Base.configurations to look like this:
      #
      #   {
      #      'development' => {
      #         'adapter'  => 'sqlite3',
      #         'database' => 'db/development.sqlite3'
      #      },
      #      'production' => {
      #         'adapter'  => 'sqlite3',
      #         'database' => 'db/production.sqlite3'
      #      }
      #   }
      config_attribute :configurations, :global => true
      self.configurations = {}

      ##
      # :singleton-method:
      # Determines whether to use Time.local (using :local) or Time.utc (using :utc) when pulling
      # dates and times from the database. This is set to :local by default.
      config_attribute :default_timezone, :global => true
      self.default_timezone = :local

      ##
      # :singleton-method:
      # Specifies the format to use when dumping the database schema with Rails'
      # Rakefile. If :sql, the schema is dumped as (potentially database-
      # specific) SQL statements. If :ruby, the schema is dumped as an
      # ActiveRecord::Schema file which can be loaded into any database that
      # supports migrations. Use :ruby if you want to have different database
      # adapters for, e.g., your development and test environments.
      config_attribute :schema_format, :global => true
      self.schema_format = :ruby

      ##
      # :singleton-method:
      # Specify whether or not to use timestamps for migration versions
      config_attribute :timestamped_migrations, :global => true
      self.timestamped_migrations = true

      ##
      # :singleton-method:
      # The connection handler
      config_attribute :connection_handler
      self.connection_handler = ConnectionAdapters::ConnectionHandler.new
    end

    module ClassMethods
      def inherited(child_class) #:nodoc:
        child_class.initialize_generated_modules
        super
      end

      def initialize_generated_modules
        # force attribute methods to be higher in inheritance hierarchy than other generated methods
        generated_attribute_methods
        generated_feature_methods
      end

      def generated_feature_methods
        @generated_feature_methods ||= begin
          mod = const_set(:GeneratedFeatureMethods, Module.new)
          include mod
          mod
        end
      end

      # Returns a string like 'Post(id:integer, title:string, body:text)'
      def inspect
        if self == Base
          super
        elsif abstract_class?
          "#{super}(abstract)"
        elsif table_exists?
          attr_list = columns.map { |c| "#{c.name}: #{c.type}" } * ', '
          "#{super}(#{attr_list})"
        else
          "#{super}(Table doesn't exist)"
        end
      end

      # Overwrite the default class equality method to provide support for association proxies.
      def ===(object)
        object.is_a?(self)
      end

      def arel_table
        @arel_table ||= Arel::Table.new(table_name, arel_engine)
      end

      def arel_engine
        @arel_engine ||= connection_handler.connection_pools[name] ? self : active_record_super.arel_engine
      end

      private

      def relation #:nodoc:
        @relation ||= Relation.new(self, arel_table)

        if finder_needs_type_condition?
          @relation.where(type_condition).create_with(inheritance_column.to_sym => sti_name)
        else
          @relation
        end
      end
    end

    # New objects can be instantiated as either empty (pass no construction parameter) or pre-set with
    # attributes but not yet saved (pass a hash with key names matching the associated table column names).
    # In both instances, valid attribute keys are determined by the column names of the associated table --
    # hence you can't have attributes that aren't part of the table columns.
    #
    # +initialize+ respects mass-assignment security and accepts either +:as+ or +:without_protection+ options
    # in the +options+ parameter.
    #
    # ==== Examples
    #   # Instantiates a single new object
    #   User.new(:first_name => 'Jamie')
    #
    #   # Instantiates a single new object using the :admin mass-assignment security role
    #   User.new({ :first_name => 'Jamie', :is_admin => true }, :as => :admin)
    #
    #   # Instantiates a single new object bypassing mass-assignment security
    #   User.new({ :first_name => 'Jamie', :is_admin => true }, :without_protection => true)
    def initialize(attributes = nil, options = {})
      @attributes = self.class.initialize_attributes(self.class.column_defaults.dup)
      @association_cache = {}
      @aggregation_cache = {}
      @attributes_cache = {}
      @new_record = true
      @readonly = false
      @destroyed = false
      @marked_for_destruction = false
      @previously_changed = {}
      @changed_attributes = {}
      @relation = nil

      ensure_proper_type

      populate_with_current_scope_attributes

      assign_attributes(attributes, options) if attributes

      yield self if block_given?
      run_callbacks :initialize
    end

    # Initialize an empty model object from +coder+. +coder+ must contain
    # the attributes necessary for initializing an empty model object. For
    # example:
    #
    #   class Post < ActiveRecord::Base
    #   end
    #
    #   post = Post.allocate
    #   post.init_with('attributes' => { 'title' => 'hello world' })
    #   post.title # => 'hello world'
    def init_with(coder)
      @attributes = self.class.initialize_attributes(coder['attributes'])
      @relation = nil

      @attributes_cache, @previously_changed, @changed_attributes = {}, {}, {}
      @association_cache = {}
      @aggregation_cache = {}
      @readonly = @destroyed = @marked_for_destruction = false
      @new_record = false
      run_callbacks :find
      run_callbacks :initialize

      self
    end

    # Duped objects have no id assigned and are treated as new records. Note
    # that this is a "shallow" copy as it copies the object's attributes
    # only, not its associations. The extent of a "deep" copy is application
    # specific and is therefore left to the application to implement according
    # to its need.
    # The dup method does not preserve the timestamps (created|updated)_(at|on).
    def initialize_dup(other)
      cloned_attributes = other.clone_attributes(:read_attribute_before_type_cast)
      cloned_attributes.delete(self.class.primary_key)

      @attributes = cloned_attributes

      _run_after_initialize_callbacks if respond_to?(:_run_after_initialize_callbacks)

      @changed_attributes = {}
      self.class.column_defaults.each do |attr, orig_value|
        @changed_attributes[attr] = orig_value if field_changed?(attr, orig_value, @attributes[attr])
      end

      @aggregation_cache = {}
      @association_cache = {}
      @attributes_cache = {}
      @new_record  = true

      ensure_proper_type
      populate_with_current_scope_attributes
      super
    end

    # Populate +coder+ with attributes about this record that should be
    # serialized. The structure of +coder+ defined in this method is
    # guaranteed to match the structure of +coder+ passed to the +init_with+
    # method.
    #
    # Example:
    #
    #   class Post < ActiveRecord::Base
    #   end
    #   coder = {}
    #   Post.new.encode_with(coder)
    #   coder # => { 'id' => nil, ... }
    def encode_with(coder)
      coder['attributes'] = attributes
    end

    # Returns true if +comparison_object+ is the same exact object, or +comparison_object+
    # is of the same type and +self+ has an ID and it is equal to +comparison_object.id+.
    #
    # Note that new records are different from any other record by definition, unless the
    # other record is the receiver itself. Besides, if you fetch existing records with
    # +select+ and leave the ID out, you're on your own, this predicate will return false.
    #
    # Note also that destroying a record preserves its ID in the model instance, so deleted
    # models are still comparable.
    def ==(comparison_object)
      super ||
        comparison_object.instance_of?(self.class) &&
        id.present? &&
        comparison_object.id == id
    end
    alias :eql? :==

    # Delegates to id in order to allow two records of the same type and id to work with something like:
    #   [ Person.find(1), Person.find(2), Person.find(3) ] & [ Person.find(1), Person.find(4) ] # => [ Person.find(1) ]
    def hash
      id.hash
    end

    # Freeze the attributes hash such that associations are still accessible, even on destroyed records.
    def freeze
      @attributes.freeze; self
    end

    # Returns +true+ if the attributes hash has been frozen.
    def frozen?
      @attributes.frozen?
    end

    # Allows sort on objects
    def <=>(other_object)
      if other_object.is_a?(self.class)
        self.to_key <=> other_object.to_key
      else
        nil
      end
    end

    # Returns +true+ if the record is read only. Records loaded through joins with piggy-back
    # attributes will be marked as read only since they cannot be saved.
    def readonly?
      @readonly
    end

    # Marks this record as read only.
    def readonly!
      @readonly = true
    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

    # Returns the contents of the record as a nicely formatted string.
    def inspect
      inspection = if @attributes
                     self.class.column_names.collect { |name|
                       if has_attribute?(name)
                         "#{name}: #{attribute_for_inspect(name)}"
                       end
                     }.compact.join(", ")
                   else
                     "not initialized"
                   end
      "#<#{self.class} #{inspection}>"
    end

    # Hackery to accomodate Syck. Remove for 4.0.
    def to_yaml(opts = {}) #:nodoc:
      if YAML.const_defined?(:ENGINE) && !YAML::ENGINE.syck?
        super
      else
        coder = {}
        encode_with(coder)
        YAML.quick_emit(self, opts) do |out|
          out.map(taguri, to_yaml_style) do |map|
            coder.each { |k, v| map.add(k, v) }
          end
        end
      end
    end

    # Hackery to accomodate Syck. Remove for 4.0.
    def yaml_initialize(tag, coder) #:nodoc:
      init_with(coder)
    end

    private

    # Under Ruby 1.9, Array#flatten will call #to_ary (recursively) on each of the elements
    # of the array, and then rescues from the possible NoMethodError. If those elements are
    # ActiveRecord::Base's, then this triggers the various method_missing's that we have,
    # which significantly impacts upon performance.
    #
    # So we can avoid the method_missing hit by explicitly defining #to_ary as nil here.
    #
    # See also http://tenderlovemaking.com/2011/06/28/til-its-ok-to-return-nil-from-to_ary/
    def to_ary # :nodoc:
      nil
    end
  end
end