class RSpec::Core::FilterableItemRepository::QueryOptimized

This implementation is much more complex, and is optimized for rare (or hopefully no) updates once the queries start. Updates incur a cost as it has to clear the memoization and keep track of applicable keys. Queries will be O(N) the first time an item is provided with a given set of applicable metadata; subsequent queries with items with the same set of applicable metadata will be O(1) due to internal memoization.

This is ideal for use by config, where filterable items (e.g. hooks) are typically added at the start of the process (e.g. in ‘spec_helper`) and then repeatedly queried as example groups and examples are defined. @private

Public Class Methods

new ()

Calls superclass method RSpec::Core::FilterableItemRepository::UpdateOptimized::new

# File rspec-core/lib/rspec/core/metadata_filter.rb, line 131
def initialize
  super
  @applicable_keys   = Set.new
  @proc_keys         = Set.new
  @memoized_lookups  = Hash.new do |hash, applicable_metadata|
    hash[applicable_metadata] = find_items_for(applicable_metadata)
  end
end

Public Instance Methods

append (item, metadata)

Calls superclass method RSpec::Core::FilterableItemRepository::UpdateOptimized#append

# File rspec-core/lib/rspec/core/metadata_filter.rb, line 140
def append(item, metadata)
  super
  handle_mutation(metadata)
end

delete (item, metadata)

Calls superclass method RSpec::Core::FilterableItemRepository::UpdateOptimized#delete

# File rspec-core/lib/rspec/core/metadata_filter.rb, line 150
def delete(item, metadata)
  super
  reconstruct_caches
end

find_items_for (metadata)

Alias for: items_for

items_for (metadata)

# File rspec-core/lib/rspec/core/metadata_filter.rb, line 155
def items_for(metadata)
  # The filtering of `metadata` to `applicable_metadata` is the key thing
  # that makes the memoization actually useful in practice, since each
  # example and example group have different metadata (e.g. location and
  # description). By filtering to the metadata keys our items care about,
  # we can ignore extra metadata keys that differ for each example/group.
  # For example, given `config.include DBHelpers, :db`, example groups
  # can be split into these two sets: those that are tagged with `:db` and those
  # that are not. For each set, this method for the first group in the set is
  # still an `O(N)` calculation, but all subsequent groups in the set will be
  # constant time lookups when they call this method.
  applicable_metadata = metadata.slice(*@applicable_keys)

  if applicable_metadata.any? { |k, _| @proc_keys.include?(k) }
    # It's unsafe to memoize lookups involving procs (since they can
    # be non-deterministic), so we skip the memoization in this case.
    find_items_for(applicable_metadata)
  else
    @memoized_lookups[applicable_metadata]
  end
end

Also aliased as: find_items_for

prepend (item, metadata)

Calls superclass method RSpec::Core::FilterableItemRepository::UpdateOptimized#prepend

# File rspec-core/lib/rspec/core/metadata_filter.rb, line 145
def prepend(item, metadata)
  super
  handle_mutation(metadata)
end