Class: DBus::Object

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

Overview

Exported object type

Exportable D-Bus object class

Objects that are going to be exported by a D-Bus service should inherit from this class. At the client side, use ProxyObject.

Defined Under Namespace

Classes: UndefinedInterface

Constant Summary collapse

@@cur_intf =

Interface

nil
@@intfs_mutex = 
Mutex.new

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(path) ⇒ Object

Create a new object with a given path. Use ObjectServer#export to export it.

Parameters:



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# File 'lib/dbus/object.rb', line 35

def initialize(path)
  @path = path
  # TODO: what parts of our API are supposed to work before we're exported?
  self.object_server = nil
end

Instance Attribute Details

#path ⇒ ObjectPath (readonly)

Returns The path of the object.

Returns:



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# File 'lib/dbus/object.rb', line 23

def path
  @path
end

Class Method Details

.camelize(str) ⇒ String

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

TODO: borrow a proven implementation

Parameters:

  • str (String)

Returns:

  • (String) 


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# File 'lib/dbus/object.rb', line 375

def self.camelize(str)
  str.split(/_/).map(&:capitalize).join("")
end

.dbus_accessor(ruby_name, type, dbus_name: nil, emits_changed_signal: nil) ⇒ void

This method returns an undefined value.

A read-write property using a pair of reader/writer methods (which must already exist). (To directly access an instance variable, use dbus_attr_accessor instead)

Uses dbus_watcher to set up the PropertiesChanged signal.

Parameters:

  • ruby_name (Symbol) —

    :foo_bar is exposed as FooBar; use dbus_name to override

  • type (Type, SingleCompleteType) —

    a signature like “s” or “a(uus)” or Type::STRING

  • dbus_name (String) (defaults to: nil) —

    if not given it is made by CamelCasing the ruby_name. foo_bar becomes FooBar to convert the Ruby convention to the DBus convention.

  • emits_changed_signal (true, false, :const, :invalidates) (defaults to: nil) —

    see EmitsChangedSignal; if unspecified, ask the interface.

Raises:



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# File 'lib/dbus/object.rb', line 213

def self.dbus_accessor(ruby_name, type, dbus_name: nil, emits_changed_signal: nil)
  raise UndefinedInterface, ruby_name if @@cur_intf.nil?

  dbus_name = make_dbus_name(ruby_name, dbus_name: dbus_name)
  property = Property.new(dbus_name, type, :readwrite, ruby_name: ruby_name)
  @@cur_intf.define(property)

  dbus_watcher(ruby_name, dbus_name: dbus_name, emits_changed_signal: emits_changed_signal)
end

.dbus_attr_accessor(ruby_name, type, dbus_name: nil, emits_changed_signal: nil) ⇒ void

This method returns an undefined value.

A read-write property accessing an instance variable. A combination of ‘attr_accessor` and dbus_accessor.

PropertiesChanged signal will be emitted whenever ‘foo_bar=` is used but not when @foo_bar is written directly.

Parameters:

  • ruby_name (Symbol) —

    :foo_bar is exposed as FooBar; use dbus_name to override

  • type (Type, SingleCompleteType) —

    a signature like “s” or “a(uus)” or Type::STRING

  • dbus_name (String) (defaults to: nil) —

    if not given it is made by CamelCasing the ruby_name. foo_bar becomes FooBar to convert the Ruby convention to the DBus convention.

  • emits_changed_signal (true, false, :const, :invalidates) (defaults to: nil) —

    see EmitsChangedSignal; if unspecified, ask the interface.



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# File 'lib/dbus/object.rb', line 153

def self.dbus_attr_accessor(ruby_name, type, dbus_name: nil, emits_changed_signal: nil)
  attr_accessor(ruby_name)

  dbus_accessor(ruby_name, type, dbus_name: dbus_name, emits_changed_signal: emits_changed_signal)
end

.dbus_attr_reader(ruby_name, type, dbus_name: nil, emits_changed_signal: nil) ⇒ void

This method returns an undefined value.

A read-only property accessing an instance variable. A combination of ‘attr_reader` and dbus_reader.

You may be instead looking for a variant which is read-write from the Ruby side: dbus_reader_attr_accessor.

Whenever the property value gets changed from “inside” the object, you should emit the ‘PropertiesChanged` signal by calling #dbus_properties_changed.

dbus_properties_changed(interface_name, {dbus_name.to_s => value}, [])

or, omitting the value in the signal,

dbus_properties_changed(interface_name, {}, [dbus_name.to_s])

Parameters:

  • ruby_name (Symbol) —

    :foo_bar is exposed as FooBar; use dbus_name to override

  • type (Type, SingleCompleteType) —

    a signature like “s” or “a(uus)” or Type::STRING

  • dbus_name (String) (defaults to: nil) —

    if not given it is made by CamelCasing the ruby_name. foo_bar becomes FooBar to convert the Ruby convention to the DBus convention.

  • emits_changed_signal (true, false, :const, :invalidates) (defaults to: nil) —

    see EmitsChangedSignal; if unspecified, ask the interface.



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# File 'lib/dbus/object.rb', line 188

def self.dbus_attr_reader(ruby_name, type, dbus_name: nil, emits_changed_signal: nil)
  attr_reader(ruby_name)

  dbus_reader(ruby_name, type, dbus_name: dbus_name, emits_changed_signal: emits_changed_signal)
end

.dbus_attr_writer(ruby_name, type, dbus_name: nil, emits_changed_signal: nil) ⇒ void

This method returns an undefined value.

A write-only property accessing an instance variable. A combination of ‘attr_writer` and dbus_writer.

Parameters:

  • ruby_name (Symbol) —

    :foo_bar is exposed as FooBar; use dbus_name to override

  • type (Type, SingleCompleteType) —

    a signature like “s” or “a(uus)” or Type::STRING

  • dbus_name (String) (defaults to: nil) —

    if not given it is made by CamelCasing the ruby_name. foo_bar becomes FooBar to convert the Ruby convention to the DBus convention.

  • emits_changed_signal (true, false, :const, :invalidates) (defaults to: nil) —

    see EmitsChangedSignal; if unspecified, ask the interface.



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# File 'lib/dbus/object.rb', line 199

def self.dbus_attr_writer(ruby_name, type, dbus_name: nil, emits_changed_signal: nil)
  attr_writer(ruby_name)

  dbus_writer(ruby_name, type, dbus_name: dbus_name, emits_changed_signal: emits_changed_signal)
end

.dbus_interface(name) ⇒ Object

Select (and create) the interface that the following defined methods belong to.

Parameters:

  • name (String) —

    interface name like “org.example.ManagerManager”

See Also:



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# File 'lib/dbus/object.rb', line 97

def self.dbus_interface(name)
  @@intfs_mutex.synchronize do
    @@cur_intf = intfs[name]
    if !@@cur_intf
      @@cur_intf = Interface.new(name) # validates the name
      # As this is a mutable class_attr, we cannot use
      #   self.intfs[name] = @@cur_intf                      # Hash#[]=
      # as that would modify parent class attr in place.
      # Using the setter lets a subclass have the new value
      # while the superclass keeps the old one.
      self.intfs = intfs.merge(name => @@cur_intf)
    end
    begin
      yield
    ensure
      @@cur_intf = nil
    end
  end
end

.dbus_method(sym, prototype = "", &block) ⇒ Object

Defines an exportable method on the object with the given name sym, prototype and the code in a block.

Parameters:

Raises:



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# File 'lib/dbus/object.rb', line 329

def self.dbus_method(sym, prototype = "", &block)
  raise UndefinedInterface, sym if @@cur_intf.nil?

  @@cur_intf.define(Method.new(sym.to_s).from_prototype(prototype))

  ruby_name = Object.make_method_name(@@cur_intf.name, sym.to_s)
  # ::Module#define_method(name) { body }
  define_method(ruby_name, &block)
end

.dbus_reader(ruby_name, type, dbus_name: nil, emits_changed_signal: nil) ⇒ void

This method returns an undefined value.

A read-only property accessing a reader method (which must already exist). (To directly access an instance variable, use dbus_attr_reader instead)

At the D-Bus side the property is read only but it makes perfect sense to implement it with a read-write attr_accessor. In that case this method uses dbus_watcher to set up the PropertiesChanged signal.

attr_accessor :foo_bar
dbus_reader :foo_bar, "s"

The above two declarations have a shorthand:

dbus_reader_attr_accessor :foo_bar, "s"

If the property value should change by other means than its attr_writer, you should emit the ‘PropertiesChanged` signal by calling #dbus_properties_changed.

dbus_properties_changed(interface_name, {dbus_name.to_s => value}, [])

or, omitting the value in the signal,

dbus_properties_changed(interface_name, {}, [dbus_name.to_s])

Parameters:

  • ruby_name (Symbol) —

    :foo_bar is exposed as FooBar; use dbus_name to override

  • type (Type, SingleCompleteType) —

    a signature like “s” or “a(uus)” or Type::STRING

  • dbus_name (String) (defaults to: nil) —

    if not given it is made by CamelCasing the ruby_name. foo_bar becomes FooBar to convert the Ruby convention to the DBus convention.

  • emits_changed_signal (true, false, :const, :invalidates) (defaults to: nil) —

    see EmitsChangedSignal; if unspecified, ask the interface.

Raises:



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# File 'lib/dbus/object.rb', line 249

def self.dbus_reader(ruby_name, type, dbus_name: nil, emits_changed_signal: nil)
  raise UndefinedInterface, ruby_name if @@cur_intf.nil?

  dbus_name = make_dbus_name(ruby_name, dbus_name: dbus_name)
  property = Property.new(dbus_name, type, :read, ruby_name: ruby_name)
  @@cur_intf.define(property)

  ruby_name_eq = "#{ruby_name}=".to_sym
  return unless method_defined?(ruby_name_eq)

  dbus_watcher(ruby_name, dbus_name: dbus_name, emits_changed_signal: emits_changed_signal)
end

.dbus_reader_attr_accessor(ruby_name, type, dbus_name: nil, emits_changed_signal: nil) ⇒ void

This method returns an undefined value.

A read-only property accessing a read-write instance variable. A combination of ‘attr_accessor` and dbus_reader.

Parameters:

  • ruby_name (Symbol) —

    :foo_bar is exposed as FooBar; use dbus_name to override

  • type (Type, SingleCompleteType) —

    a signature like “s” or “a(uus)” or Type::STRING

  • dbus_name (String) (defaults to: nil) —

    if not given it is made by CamelCasing the ruby_name. foo_bar becomes FooBar to convert the Ruby convention to the DBus convention.

  • emits_changed_signal (true, false, :const, :invalidates) (defaults to: nil) —

    see EmitsChangedSignal; if unspecified, ask the interface.



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# File 'lib/dbus/object.rb', line 164

def self.dbus_reader_attr_accessor(ruby_name, type, dbus_name: nil, emits_changed_signal: nil)
  attr_accessor(ruby_name)

  dbus_reader(ruby_name, type, dbus_name: dbus_name, emits_changed_signal: emits_changed_signal)
end

.dbus_signal(sym, prototype = "") ⇒ Object

Defines a signal for the object with a given name sym and prototype.

Raises:



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# File 'lib/dbus/object.rb', line 351

def self.dbus_signal(sym, prototype = "")
  raise UndefinedInterface, sym if @@cur_intf.nil?

  cur_intf = @@cur_intf
  signal = Signal.new(sym.to_s).from_prototype(prototype)
  cur_intf.define(signal)

  # ::Module#define_method(name) { body }
  define_method(sym.to_s) do |*args|
    emit(cur_intf, signal, *args)
  end
end

.dbus_watcher(ruby_name, dbus_name: nil, emits_changed_signal: nil) ⇒ void

This method returns an undefined value.

Enables automatic sending of the PropertiesChanged signal. For ruby_name ‘foo_bar`, wrap `foo_bar=` so that it sends the signal for FooBar. The original version remains as `_original_foo_bar=`.

Parameters:

  • ruby_name (Symbol) —

    :foo_bar and :foo_bar= both mean the same thing

  • dbus_name (String) (defaults to: nil) —

    if not given it is made by CamelCasing the ruby_name. foo_bar becomes FooBar to convert the Ruby convention to the DBus convention.

  • emits_changed_signal (true, false, :const, :invalidates) (defaults to: nil) —

    see EmitsChangedSignal; if unspecified, ask the interface.

Raises:



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# File 'lib/dbus/object.rb', line 291

def self.dbus_watcher(ruby_name, dbus_name: nil, emits_changed_signal: nil)
  raise UndefinedInterface, ruby_name if @@cur_intf.nil?

  interface_name = @@cur_intf.name

  ruby_name = ruby_name.to_s.sub(/=$/, "").to_sym
  ruby_name_eq = "#{ruby_name}=".to_sym
  original_ruby_name_eq = "_original_#{ruby_name_eq}"

  dbus_name = make_dbus_name(ruby_name, dbus_name: dbus_name)

  emits_changed_signal = EmitsChangedSignal.new(emits_changed_signal, interface: @@cur_intf)

  # the argument order is alias_method(new_name, existing_name)
  alias_method original_ruby_name_eq, ruby_name_eq
  define_method ruby_name_eq do |value|
    result = public_send(original_ruby_name_eq, value)

    case emits_changed_signal.value
    when true
      # signature: "interface:s, changed_props:a{sv}, invalidated_props:as"
      dbus_properties_changed(interface_name, { dbus_name.to_s => value }, [])
    when :invalidates
      dbus_properties_changed(interface_name, {}, [dbus_name.to_s])
    when :const
      # Oh my, seeing a value change of a supposedly constant property.
      # Maybe should have raised at declaration time, don't make a fuss now.
    when false
      # Do nothing
    end

    result
  end
end

.dbus_writer(ruby_name, type, dbus_name: nil, emits_changed_signal: nil) ⇒ void

This method returns an undefined value.

A write-only property accessing a writer method (which must already exist). (To directly access an instance variable, use dbus_attr_writer instead)

Uses dbus_watcher to set up the PropertiesChanged signal.

Parameters:

  • ruby_name (Symbol) —

    :foo_bar is exposed as FooBar; use dbus_name to override

  • type (Type, SingleCompleteType) —

    a signature like “s” or “a(uus)” or Type::STRING

  • dbus_name (String) (defaults to: nil) —

    if not given it is made by CamelCasing the ruby_name. foo_bar becomes FooBar to convert the Ruby convention to the DBus convention.

  • emits_changed_signal (true, false, :const, :invalidates) (defaults to: nil) —

    see EmitsChangedSignal; if unspecified, ask the interface.

Raises:



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# File 'lib/dbus/object.rb', line 269

def self.dbus_writer(ruby_name, type, dbus_name: nil, emits_changed_signal: nil)
  raise UndefinedInterface, ruby_name if @@cur_intf.nil?

  dbus_name = make_dbus_name(ruby_name, dbus_name: dbus_name)
  property = Property.new(dbus_name, type, :write, ruby_name: ruby_name)
  @@cur_intf.define(property)

  dbus_watcher(ruby_name, dbus_name: dbus_name, emits_changed_signal: emits_changed_signal)
end

.emits_changed_signal=(value) ⇒ Object

Declare the behavior of PropertiesChanged signal, common for all properties in this interface (individual properties may override it)

Examples:

self.emits_changed_signal = :invalidates

Parameters:

  • value (true, false, :const, :invalidates)

Raises:



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# File 'lib/dbus/object.rb', line 131

def self.emits_changed_signal=(value)
  raise UndefinedInterface, :emits_changed_signal if @@cur_intf.nil?

  @@cur_intf.emits_changed_signal = EmitsChangedSignal.new(value)
end

.make_dbus_name(ruby_name, dbus_name: nil) ⇒ Symbol

Make a D-Bus conventional name, CamelCased.

Parameters:

  • ruby_name (String, Symbol) —

    eg :do_something

  • dbus_name (String, Symbol, nil) (defaults to: nil) —

    use this if given

Returns:

  • (Symbol) —

    eg DoSomething



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# File 'lib/dbus/object.rb', line 383

def self.make_dbus_name(ruby_name, dbus_name: nil)
  dbus_name ||= camelize(ruby_name.to_s)
  dbus_name.to_sym
end

.make_method_name(intfname, methname) ⇒ Object

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Helper method that returns a method name generated from the interface name intfname and method name methname.



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# File 'lib/dbus/object.rb', line 367

def self.make_method_name(intfname, methname)
  "#{intfname}%%#{methname}"
end

Instance Method Details

#dbus_lookup_property(interface_name, property_name) ⇒ Property

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Parameters:

  • interface_name (String)
  • property_name (String)

Returns:

Raises:



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# File 'lib/dbus/object.rb', line 412

def dbus_lookup_property(interface_name, property_name)
  # what should happen for unknown properties
  # plasma: InvalidArgs (propname), UnknownInterface (interface)
  # systemd: UnknownProperty
  interface = intfs[interface_name]
  if !interface
    raise DBus.error("org.freedesktop.DBus.Error.UnknownProperty"),
          "Property '#{interface_name}.#{property_name}' (on object '#{@path}') not found: no such interface"
  end

  property = interface.properties[property_name.to_sym]
  if !property
    raise DBus.error("org.freedesktop.DBus.Error.UnknownProperty"),
          "Property '#{interface_name}.#{property_name}' (on object '#{@path}') not found"
  end

  property
end

#dbus_properties_changed(interface_name, changed_props, invalidated_props) ⇒ Object

Use this instead of calling PropertiesChanged directly. This one considers not only the PC signature (which says that all property values are variants) but also the specific property type.

Parameters:

  • interface_name (String) —

    interface name like “org.example.ManagerManager”

  • changed_props (Hash{String => ::Object}) —

    changed properties (D-Bus names) and their values.

  • invalidated_props (Array<String>) —

    names of properties whose changed value is not specified



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# File 'lib/dbus/object.rb', line 396

def dbus_properties_changed(interface_name, changed_props, invalidated_props)
  typed_changed_props = changed_props.map do |dbus_name, value|
    property = dbus_lookup_property(interface_name, dbus_name)
    type = property.type
    typed_value = Data.make_typed(type, value)
    variant = Data::Variant.new(typed_value, member_type: type)
    [dbus_name, variant]
  end.to_h
  PropertiesChanged(interface_name, typed_changed_props, invalidated_props)
end

#dispatch(msg) ⇒ Object

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Dispatch a message msg to call exported methods

Parameters:

  • msg (Message) —

    only METHOD_CALLS do something



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# File 'lib/dbus/object.rb', line 58

def dispatch(msg)
  case msg.message_type
  when Message::METHOD_CALL
    reply = nil
    begin
      iface = intfs[msg.interface]
      if !iface
        raise DBus.error("org.freedesktop.DBus.Error.UnknownMethod"),
              "Interface \"#{msg.interface}\" of object \"#{msg.path}\" doesn't exist"
      end
      member_sym = msg.member.to_sym
      meth = iface.methods[member_sym]
      if !meth
        raise DBus.error("org.freedesktop.DBus.Error.UnknownMethod"),
              "Method \"#{msg.member}\" on interface \"#{msg.interface}\" of object \"#{msg.path}\" doesn't exist"
      end
      methname = Object.make_method_name(msg.interface, msg.member)
      retdata = method(methname).call(*msg.params)
      retdata = [*retdata]

      reply = Message.method_return(msg)
      rsigs = meth.rets.map(&:type)
      rsigs.zip(retdata).each do |rsig, rdata|
        reply.add_param(rsig, rdata)
      end
    rescue StandardError => e
      dbus_msg_exc = msg.annotate_exception(e)
      reply = ErrorMessage.from_exception(dbus_msg_exc).reply_to(msg)
    end
    # TODO: this method chain is too long,
    # we should probably just return reply [Message] like we get a [Message]
    object_server.connection.message_queue.push(reply)
  end
end

#emit(intf, sig, *args) ⇒ Object

Emits a signal from the object with the given interface, signal sig and arguments args.

Parameters:



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# File 'lib/dbus/object.rb', line 344

def emit(intf, sig, *args)
  raise "Cannot emit signal #{intf.name}.#{sig.name} before #{path} is exported" if object_server.nil?

  object_server.connection.emit(nil, self, intf, sig, *args)
end

#interfaces_and_properties ⇒ Hash{String => Hash{String => Data::Base}}

Generates information about interfaces and properties of the object

Returns a hash containing interfaces names as keys. Each value is the same hash that would be returned by the org.freedesktop.DBus.Properties.GetAll() method for that combination of object path and interface. If an interface has no properties, the empty hash is returned.

Returns:

  • (Hash{String => Hash{String => Data::Base}}) —

    interface -> property -> value



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# File 'lib/dbus/object.rb', line 440

def interfaces_and_properties
  get_all_method = self.class.make_method_name("org.freedesktop.DBus.Properties", :GetAll)

  intfs.keys.each_with_object({}) do |interface, hash|
    hash[interface] = public_send(get_all_method, interface).first
  end
end

#object_server ⇒ ObjectServer

Returns the server the object is exported by.

Returns:



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# File 'lib/dbus/object.rb', line 42

def object_server
  # tests may mock the old ivar
  @object_server || @service
end

#object_server=(server) ⇒ Object

Note:

only the server itself should call this in its #export/#unexport

Parameters:

  • server (ObjectServer) —

    the server the object is exported by



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# File 'lib/dbus/object.rb', line 49

def object_server=(server)
  # until v0.22.1 there was attr_writer :service
  # so subclasses only could use @service
  @object_server = @service = server
end