Class: Volt::Persistors::ArrayStore

Inherits:
Store show all
Includes:
StoreState
Defined in:
lib/volt/models/persistors/array_store.rb

Constant Summary collapse

@@query_pool = 
QueryListenerPool.new

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from Store

#clear_identity_map, #read_new_model, #saved?

Methods inherited from Base

#auto_generate_id, #changed, #root_model

Constructor Details

#initialize(model, tasks = nil) ⇒ ArrayStore

Returns a new instance of ArrayStore.



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# File 'lib/volt/models/persistors/array_store.rb', line 20

def initialize(model, tasks = nil)
  # Keep a hash of all ids in this collection
  @ids = {}

  super

  # The listener event counter keeps track of how many things are listening
  # on this model and loads/unloads data when in use.
  @listener_event_counter = EventCounter.new(
    -> { load_data },
    -> { stop_listening }
  )

  # The root dependency tracks how many listeners are on the ArrayModel
  # @root_dep = Dependency.new(@listener_event_counter.method(:add), @listener_event_counter.method(:remove))
  @root_dep = Dependency.new(method(:listener_added), method(:listener_removed))

  @query = @model.options[:query]
end

Instance Attribute Details

#model ⇒ Object (readonly)

Returns the value of attribute model.



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# File 'lib/volt/models/persistors/array_store.rb', line 14

def model
  @model
end

#root_dep ⇒ Object (readonly)

Returns the value of attribute root_dep.



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# File 'lib/volt/models/persistors/array_store.rb', line 14

def root_dep
  @root_dep
end

Class Method Details

.query_pool ⇒ Object 



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# File 'lib/volt/models/persistors/array_store.rb', line 16

def self.query_pool
  @@query_pool
end

Instance Method Details

#add(index, data) ⇒ Object

Called from backend when an item is added



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# File 'lib/volt/models/persistors/array_store.rb', line 239

def add(index, data)
  $loading_models = true

  Model.no_validate do
    data_id = data['id'] || data[:id]

    # Don't add if the model is already in the ArrayModel (from the client already)
    unless @ids[data_id]
      @ids[data_id] = true
      # Find the existing model, or create one
      new_model = @@identity_map.find(data_id) do
        new_options = @model.options.merge(path: @model.path + [:[]], parent: @model)
        @model.new_model(data, new_options, :loaded)
      end

      @model.insert(index, new_model)
    end
  end

  $loading_models = false
end

#add_query_part(*args) ⇒ Cursor

Add query part adds a [method_name, *arguments] array to the query. This will then be passed to the backend to run the query.

Returns:



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# File 'lib/volt/models/persistors/array_store.rb', line 160

def add_query_part(*args)
  opts = @model.options
  query = opts[:query] ? opts[:query].deep_clone : []
  query << args

  # Make a new opts hash with changed query
  opts = opts.merge(query: query)
  Cursor.new([], opts)
end

#added(model, index) ⇒ Object

Called when the client adds an item.



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# File 'lib/volt/models/persistors/array_store.rb', line 288

def added(model, index)
  if model.persistor
    # Tell the persistor it was added, return the promise
    promise = model.persistor.add_to_collection

    # Track the the model got added
    @ids[model.id] = true

    promise
  end
end

#channel_name ⇒ Object 



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# File 'lib/volt/models/persistors/array_store.rb', line 283

def channel_name
  @model.path[-1]
end

#clear ⇒ Object

Called when all models are removed



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# File 'lib/volt/models/persistors/array_store.rb', line 279

def clear
  @ids = {}
end

#event_added(event, first, first_for_event) ⇒ Object

Called when an each binding is listening



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# File 'lib/volt/models/persistors/array_store.rb', line 57

def event_added(event, first, first_for_event)
  # First event, we load the data.
  @listener_event_counter.add if first
end

#event_removed(event, last, last_for_event) ⇒ Object

Called when an each binding stops listening



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# File 'lib/volt/models/persistors/array_store.rb', line 63

def event_removed(event, last, last_for_event)
  # Remove listener where there are no more events on this model
  @listener_event_counter.remove if last
end

#fetch(&block) ⇒ Object Also known as: then

Returns a promise that is resolved/rejected when the query is complete. Any passed block will be passed to the promises then. Then will be passed the model.



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# File 'lib/volt/models/persistors/array_store.rb', line 212

def fetch(&block)
  Volt.logger.warn('Deprication warning: in 0.9.3.pre4, all query methods on store now return Promises, so you can juse use .all or .first instead of .first')
  promise = Promise.new

  # Run the block after resolve if a block is passed in
  promise = promise.then(&block) if block

  if @model.loaded_state == :loaded
    promise.resolve(@model)
  else
    proc do |comp|
      if @model.loaded_state == :loaded
        promise.resolve(@model)

        comp.stop
      end
    end.watch!
  end

  promise
end

#inspect ⇒ Object 



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# File 'lib/volt/models/persistors/array_store.rb', line 52

def inspect
  "<#{self.class}:#{object_id} #{@model.path.inspect} #{@query.inspect}>"
end

#listener_added ⇒ Object

Called by child models to track their listeners



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# File 'lib/volt/models/persistors/array_store.rb', line 69

def listener_added
  @listener_event_counter.add
end

#listener_removed ⇒ Object

Called by child models to track their listeners



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# File 'lib/volt/models/persistors/array_store.rb', line 74

def listener_removed
  @listener_event_counter.remove
end

#load_data ⇒ Object

Called the first time data is requested from this collection



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# File 'lib/volt/models/persistors/array_store.rb', line 101

def load_data
  Computation.run_without_tracking do
    loaded_state = @model.loaded_state

    # Don't load data from any queried
    if loaded_state == :not_loaded || loaded_state == :dirty
      @model.change_state_to(:loaded_state, :loading)

      run_query
    end
  end
end

#loaded(initial_state = nil) ⇒ Object 



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# File 'lib/volt/models/persistors/array_store.rb', line 40

def loaded(initial_state = nil)
  super

  # Setup up the query listener, and if it is already listening, then
  # go ahead and load that data in.  This allows us to use it immediately
  # if the data is loaded in another place.
  if query_listener.listening
    query_listener.add_store(self)
    @added_to_query = true
  end
end

#query_listener ⇒ Object

Looks up the query listener for this ArrayStore



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# File 'lib/volt/models/persistors/array_store.rb', line 125

def query_listener
  return @query_listener if @query_listener

  collection = @model.path.last
  query = @query

  # Scope to the parent
  if @model.path.size > 1
    parent = @model.parent

    parent.persistor.ensure_setup if parent.persistor

    if parent && (attrs = parent.attributes) && attrs[:id]
      query = query.dup

      query << [:find, { :"#{@model.path[-3].singularize}_id" => attrs[:id] }]
    end
  end

  query = Volt::DataStore.adaptor_client.normalize_query(query)

  @query_listener ||= @@query_pool.lookup(collection, query) do
    # Create if it does not exist
    QueryListener.new(@@query_pool, @tasks, collection, query)
  end

  # @@query_pool.print

  @query_listener
end

#remove(ids) ⇒ Object

Called from the server when it removes an item.



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# File 'lib/volt/models/persistors/array_store.rb', line 262

def remove(ids)
  $loading_models = true
  ids.each do |id|
    # TODO: optimize this delete so we don't need to loop
    @model.each_with_index do |model, index|
      if model.id == id
        @ids.delete(id)
        del = @model.delete_at(index)
        break
      end
    end
  end

  $loading_models = false
end

#removed(model) ⇒ Object

Called when the client removes an item



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# File 'lib/volt/models/persistors/array_store.rb', line 301

def removed(model)
  if model.persistor
    # Tell the persistor it was removed
    model.persistor.remove_from_collection

    @ids.delete(model.id)
  end

  if defined?($loading_models) && $loading_models
    return
  else
    StoreTasks.delete(channel_name, model.attributes[:id])
  end
end

#run_once_loaded(block) ⇒ Object

Call a method on the model once the model is loaded. Return a promise that will resolve the result of the method, or reject with any Exceptions.



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# File 'lib/volt/models/persistors/array_store.rb', line 173

def run_once_loaded(block)
  promise = Promise.new

  # call once the method is loaded.
  model_loaded = proc do
    begin
      result = yield
      promise.resolve(result)
    rescue Exception => error
      promise.reject(error)
    end
  end

  # Run the block after resolve if a block is passed in
  if block
    promise2 = promise.then do |val|
      block.call(val)
    end
  else
    promise2 = promise
  end

  if @model.loaded_state == :loaded
    model_loaded.call
  else
    proc do |comp|
      if @model.loaded_state == :loaded
        model_loaded.call

        comp.stop
      end
    end.watch!
  end

  promise2
end

#run_query ⇒ Object 



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# File 'lib/volt/models/persistors/array_store.rb', line 114

def run_query
  unless @added_to_query
    @model.clear

    @added_to_query = true
    query_listener.add_store(self)
  end
end

#stop_listening ⇒ Object

Called when an event is removed and we no longer want to keep in sync with the database. The data is kept in memory and the model’s loaded_state is marked as “dirty” meaning it may not be in sync.



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# File 'lib/volt/models/persistors/array_store.rb', line 81

def stop_listening
  Timers.client_set_timeout(5000) do
    Computation.run_without_tracking do
      if @listener_event_counter.count == 0
        if @added_to_query
          @query_listener.remove_store(self)
          @query_listener = nil

          @added_to_query = nil
        end

        @model.change_state_to(:loaded_state, :dirty)
      end
    end
  end

  Timers.flush_next_tick_timers! if Volt.server?
end