Class: Mochigome::ModelGraph

Inherits:
Object
  • Object
show all
Defined in:
lib/model_graph.rb

Instance Method Summary collapse

Constructor Details

#initialize ⇒ ModelGraph

Returns a new instance of ModelGraph.



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# File 'lib/model_graph.rb', line 10

def initialize
  @graphed_models = Set.new
  @table_to_model = {}
  @assoc_graph = RGL::DirectedAdjacencyGraph.new(OrderedSet)
  # TODO Also maybe need to do this with hashes used internally in traversal
  @assoc_graph.instance_variable_set( # Make path choice more predictable
    :@vertice_dict,
    ActiveSupport::OrderedHash.new
  )
  @edge_conditions = {}
  @shortest_paths = {}
end

Instance Method Details

#edge_condition(u, v) ⇒ Object 



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# File 'lib/model_graph.rb', line 61

def edge_condition(u, v)
  @edge_conditions[[u,v]]
end

#expr_models(e) ⇒ Object

Take an expression and return a Set of all models it references



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# File 'lib/model_graph.rb', line 24

def expr_models(e)
  r = Set.new
  if e.is_a?(Array)
    e.each{|sub_e| r += expr_models(sub_e)}
    return r
  end
  [:expr, :left, :right, :expressions].each do |m|
    r += expr_models(e.send(m)) if e.respond_to?(m)
  end
  if e.respond_to?(:relation)
    model = nil
    begin
      model = @table_to_model[e.relation.name] or
        raise ModelSetupError.new("Table lookup error: #{e.relation.name}")
    rescue ModelSetupError
      Dir.glob(RAILS_ROOT + '/app/models/*.rb').each do |path|
        clsname = File.basename(path).sub(/\.rb$/, "").classify
        require File.expand_path(path) unless Object.const_defined?(clsname)
      end
      Object.subclasses_of(ActiveRecord::Base).each do |m|
        if m.table_name == e.relation.name
          model = m
          break
        end
      end
      raise unless model
    end
    r.add model
  end
  r
end

#path_thru(models) ⇒ Object 



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# File 'lib/model_graph.rb', line 65

def path_thru(models)
  update_assoc_graph(models)
  model_queue = models.dup
  path = [model_queue.shift]
  until model_queue.empty?
    src = path.last
    tgt = model_queue.shift
    next if src == tgt
    real_src = src.to_real_model
    real_tgt = tgt.to_real_model
    unless real_src == real_tgt
      seg = @shortest_paths[[real_src,real_tgt]]
      return nil unless seg
      path.concat seg.take(seg.size-1).drop(1)
    end
    path << tgt
  end

  # Don't return any paths that double back
  return nil unless path.uniq.size == path.size
  path
end

#relation_init(model) ⇒ Object 



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# File 'lib/model_graph.rb', line 56

def relation_init(model)
  update_assoc_graph([model])
  model.arel_table.project # Project to convert Arel::Table to Arel::Rel
end