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# encoding: utf-8
require "mongoid/criterion/inspection"
require "mongoid/criterion/findable"
require "mongoid/criterion/modifiable"
require "mongoid/criterion/scoping"
module Mongoid
# The +Criteria+ class is the core object needed in Mongoid to retrieve
# objects from the database. It is a DSL that essentially sets up the
# selector and options arguments that get passed on to a Mongo::Collection
# in the Ruby driver. Each method on the +Criteria+ returns self to they
# can be chained in order to create a readable criterion to be executed
# against the database.
class Criteria
include Enumerable
include Contextual
include Origin::Queryable
include Criterion::Inspection
include Criterion::Findable
include Criterion::Modifiable
include Criterion::Scoping
attr_accessor :embedded, :klass
# Returns true if the supplied +Enumerable+ or +Criteria+ is equal to the results
# of this +Criteria+ or the criteria itself.
#
# @note This will force a database load when called if an enumerable is passed.
#
# @param [ Object ] other The other +Enumerable+ or +Criteria+ to compare to.
#
# @return [ true, false ] If the objects are equal.
#
# @since 1.0.0
def ==(other)
return super if other.respond_to?(:selector)
entries == other
end
# Needed to properly get a criteria back as json
#
# @example Get the criteria as json.
# Person.where(:title => "Sir").as_json
#
# @param [ Hash ] options Options to pass through to the serializer.
#
# @return [ String ] The JSON string.
def as_json(options = nil)
entries.as_json(options)
end
# Tells the criteria that the cursor that gets returned needs to be
# cached. This is so multiple iterations don't hit the database multiple
# times, however this is not advisable when working with large data sets
# as the entire results will get stored in memory.
#
# @example Flag the criteria as cached.
# criteria.cache
#
# @return [ Criteria ] The cloned criteria.
def cache
crit = clone
crit.options.merge!(cache: true)
crit
end
# Will return true if the cache option has been set.
#
# @example Is the criteria cached?
# criteria.cached?
#
# @return [ true, false ] If the criteria is flagged as cached.
def cached?
options[:cache] == true
end
# Get the documents from the embedded criteria.
#
# @example Get the documents.
# criteria.documents
#
# @return [ Array<Document> ] The documents.
#
# @since 3.0.0
def documents
@documents ||= []
end
# Set the embedded documents on the criteria.
#
# @example Set the documents.
#
# @param [ Array<Document> ] docs The embedded documents.
#
# @return [ Array<Document> ] The embedded documents.
#
# @since 3.0.0
def documents=(docs)
@documents = docs
end
# Is the criteria for embedded documents?
#
# @example Is the criteria for embedded documents?
# criteria.embedded?
#
# @return [ true, false ] If the criteria is embedded.
#
# @since 3.0.0
def embedded?
!!@embedded
end
# Extract a single id from the provided criteria. Could be in an $and
# query or a straight _id query.
#
# @example Extract the id.
# criteria.extract_id
#
# @return [ Object ] The id.
#
# @since 2.3.0
def extract_id
selector.extract_id
end
# Adds a criterion to the +Criteria+ that specifies additional options
# to be passed to the Ruby driver, in the exact format for the driver.
#
# @example Add extra params to the criteria.
# criteria.extras(:limit => 20, :skip => 40)
#
# @param [ Hash ] extras The extra driver options.
#
# @return [ Criteria ] The cloned criteria.
#
# @since 2.0.0
def extras(extras)
crit = clone
crit.options.merge!(extras)
crit
end
# Get the list of included fields.
#
# @example Get the field list.
# criteria.field_list
#
# @return [ Array<String> ] The fields.
#
# @since 2.0.0
def field_list
if options[:fields]
options[:fields].keys.reject{ |key| key == "_type" }
else
[]
end
end
# When freezing a criteria we need to initialize the context first
# otherwise the setting of the context on attempted iteration will raise a
# runtime error.
#
# @example Freeze the criteria.
# criteria.freeze
#
# @return [ Criteria ] The frozen criteria.
#
# @since 2.0.0
def freeze
context and inclusions and super
end
# Initialize the new criteria.
#
# @example Init the new criteria.
# Criteria.new(Band)
#
# @param [ Class ] klass The model class.
#
# @since 1.0.0
def initialize(klass)
@klass = klass
super(klass.aliased_fields, klass.fields)
end
# Eager loads all the provided relations. Will load all the documents
# into the identity map who's ids match based on the extra query for the
# ids.
#
# @note This will only work if Mongoid's identity map is enabled. To do
# so set identity_map_enabled: true in your mongoid.yml
#
# @note This will work for embedded relations that reference another
# collection via belongs_to as well.
#
# @note Eager loading brings all the documents into memory, so there is a
# sweet spot on the performance gains. Internal benchmarks show that
# eager loading becomes slower around 100k documents, but this will
# naturally depend on the specific application.
#
# @example Eager load the provided relations.
# Person.includes(:posts, :game)
#
# @param [ Array<Symbol> ] relations The names of the relations to eager
# load.
#
# @return [ Criteria ] The cloned criteria.
#
# @since 2.2.0
def includes(*relations)
relations.flatten.each do |name|
metadata = klass.reflect_on_association(name)
raise Errors::InvalidIncludes.new(klass, relations) unless metadata
inclusions.push(metadata) unless inclusions.include?(metadata)
end
clone
end
# Get a list of criteria that are to be executed for eager loading.
#
# @example Get the eager loading inclusions.
# Person.includes(:game).inclusions
#
# @return [ Array<Metadata> ] The inclusions.
#
# @since 2.2.0
def inclusions
@inclusions ||= []
end
# Set the inclusions for the criteria.
#
# @example Set the inclusions.
# criteria.inclusions = [ meta ]
#
# @param [ Array<Metadata> ] The inclusions.
#
# @return [ Array<Metadata> ] The new inclusions.
#
# @since 3.0.0
def inclusions=(value)
@inclusions = value
end
# Merges another object with this +Criteria+ and returns a new criteria.
# The other object may be a +Criteria+ or a +Hash+. This is used to
# combine multiple scopes together, where a chained scope situation
# may be desired.
#
# @example Merge the criteria with another criteria.
# criteri.merge(other_criteria)
#
# @param [ Criteria ] other The other criterion to merge with.
#
# @return [ Criteria ] A cloned self.
def merge(other)
crit = clone
crit.merge!(other)
crit
end
# Merge the other criteria into this one.
#
# @example Merge another criteria into this criteria.
# criteria.merge(Person.where(name: "bob"))
#
# @param [ Criteria ] other The criteria to merge in.
#
# @return [ Criteria ] The merged criteria.
#
# @since 3.0.0
def merge!(other)
criteria = other.to_criteria
selector.merge!(criteria.selector)
options.merge!(criteria.options)
self.documents = criteria.documents.dup unless criteria.documents.empty?
self.scoping_options = criteria.scoping_options
self.inclusions = (inclusions + criteria.inclusions.dup).uniq
self
end
# Overriden to include _type in the fields.
#
# @example Limit the fields returned from the database.
# Band.only(:name)
#
# @param [ Array<Symbol> ] args The names of the fields.
#
# @return [ Criteria ] The cloned criteria.
#
# @since 1.0.0
def only(*args)
return clone if args.flatten.empty?
args = args.flatten
if klass.hereditary?
super(*args.push(:_type))
else
super(*args)
end
end
# Returns true if criteria responds to the given method.
#
# @example Does the criteria respond to the method?
# crtiteria.respond_to?(:each)
#
# @param [ Symbol ] name The name of the class method on the +Document+.
# @param [ true, false ] include_private Whether to include privates.
#
# @return [ true, false ] If the criteria responds to the method.
def respond_to?(name, include_private = false)
super || klass.respond_to?(name) || entries.respond_to?(name, include_private)
end
alias :to_ary :to_a
# Convenience for objects that want to be merged into a criteria.
#
# @example Convert to a criteria.
# criteria.to_criteria
#
# @return [ Criteria ] self.
#
# @since 3.0.0
def to_criteria
self
end
# Convert the criteria to a proc.
#
# @example Convert the criteria to a proc.
# criteria.to_proc
#
# @return [ Proc ] The wrapped criteria.
#
# @since 3.0.0
def to_proc
->{ self }
end
# Adds a criterion to the +Criteria+ that specifies a type or an Array of
# types that must be matched.
#
# @example Match only specific models.
# criteria.type('Browser')
# criteria.type(['Firefox', 'Browser'])
#
# @param [ Array<String> ] types The types to match against.
#
# @return [ Criteria ] The cloned criteria.
def type(types)
any_in(_type: Array(types))
end
# This is the general entry point for most MongoDB queries. This either
# creates a standard field: value selection, and expanded selection with
# the use of hash methods, or a $where selection if a string is provided.
#
# @example Add a standard selection.
# criteria.where(name: "syd")
#
# @example Add a javascript selection.
# criteria.where("this.name == 'syd'")
#
# @param [ String, Hash ] criterion The javascript or standard selection.
#
# @raise [ UnsupportedJavascript ] If provided a string and the criteria
# is embedded.
#
# @return [ Criteria ] The cloned selectable.
#
# @since 1.0.0
def where(expression)
if expression.is_a?(::String) && embedded?
raise Errors::UnsupportedJavascript.new(klass, expression)
end
super
end
# Get a version of this criteria without the options.
#
# @example Get the criteria without options.
# criteria.without_options
#
# @return [ Criteria ] The cloned criteria.
#
# @since 3.0.4
def without_options
crit = clone
crit.options.clear
crit
end
# Find documents by the provided javascript and scope. Uses a $where but is
# different from +Criteria#where+ in that it will pass a code object to the
# query instead of a pure string. Safe against Javascript injection
# attacks.
#
# @example Find by javascript.
# Band.for_js("this.name = param", param: "Tool")
#
# @param [ String ] javascript The javascript to execute in the $where.
# @param [ Hash ] scope The scope for the code.
#
# @return [ Criteria ] The criteria.
#
# @since 3.1.0
def for_js(javascript, scope = {})
js_query(Moped::BSON::Code.new(javascript, scope))
end
private
# Are documents in the query missing, and are we configured to raise an
# error?
#
# @api private
#
# @example Check for missing documents.
# criteria.check_for_missing_documents!([], [ 1 ])
#
# @param [ Array<Document> ] result The result.
# @param [ Array<Object> ] ids The ids.
#
# @raise [ Errors::DocumentNotFound ] If none are found and raising an
# error.
#
# @since 3.0.0
def check_for_missing_documents!(result, ids)
if (result.size < ids.size) && Mongoid.raise_not_found_error
raise Errors::DocumentNotFound.new(klass, ids, ids - result.map(&:_id))
end
end
# Clone or dup the current +Criteria+. This will return a new criteria with
# the selector, options, klass, embedded options, etc intact.
#
# @api private
#
# @example Clone a criteria.
# criteria.clone
#
# @example Dup a criteria.
# criteria.dup
#
# @param [ Criteria ] other The criteria getting cloned.
#
# @return [ nil ] nil.
#
# @since 1.0.0
def initialize_copy(other)
@inclusions = other.inclusions.dup
@scoping_options = other.scoping_options
@documents = other.documents.dup
@context = nil
super
end
# Used for chaining +Criteria+ scopes together in the for of class methods
# on the +Document+ the criteria is for.
#
# @example Handle method missing.
# criteria.method_missing(:name)
#
# @param [ Symbol ] name The method name.
# @param [ Array ] args The arguments.
#
# @return [ Object ] The result of the method call.
#
# @since 1.0.0
def method_missing(name, *args, &block)
if klass.respond_to?(name)
klass.send(:with_scope, self) do
klass.send(name, *args, &block)
end
else
return entries.send(name, *args)
end
end
# For models where inheritance is at play we need to add the type
# selection.
#
# @example Add the type selection.
# criteria.merge_type_selection
#
# @return [ true, false ] If type selection was added.
#
# @since 3.0.3
def merge_type_selection
selector.merge!(type_selection) if type_selectable?
end
# Is the criteria type selectable?
#
# @api private
#
# @example If the criteria type selectable?
# criteria.type_selectable?
#
# @return [ true, false ] If type selection should be added.
#
# @since 3.0.3
def type_selectable?
klass.hereditary? && !selector.keys.include?(:_type)
end
# Get the selector for type selection.
#
# @api private
#
# @example Get a type selection hash.
# criteria.type_selection
#
# @return [ Hash ] The type selection.
#
# @since 3.0.3
def type_selection
{ _type: { "$in" => klass._types }}
end
# Get a new selector with type selection in it.
#
# @api private
#
# @example Get a selector with type selection.
# criteria.selector_with_type_selection
#
# @return [ Hash ] The selector.
#
# @since 3.0.3
def selector_with_type_selection
type_selectable? ? selector.merge(type_selection) : selector
end
end
end
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