Class: DBus::PacketMarshaller
- Inherits:
-
Object
- Object
- DBus::PacketMarshaller
- Defined in:
- lib/dbus/marshall.rb
Overview
D-Bus packet marshaller class
Class that handles the conversion (marshalling) of Ruby objects to (binary) payload data.
Instance Attribute Summary collapse
-
#packet ⇒ Object
readonly
The current or result packet.
Class Method Summary collapse
-
.make_variant(value) ⇒ Object
Make a [signature, value] pair for a variant.
Instance Method Summary collapse
-
#align(a) ⇒ Object
Align the buffer with NULL (0) bytes on a byte length of a.
-
#append(type, val) ⇒ Object
Append a value val to the packet based on its type.
-
#append_signature(str) ⇒ Object
Append the the signature signature itself to the packet.
-
#append_string(str) ⇒ Object
Append the the string str itself to the packet.
-
#array(type) ⇒ Object
Append the array type type to the packet and allow for appending the child elements.
-
#initialize(offset = 0) ⇒ PacketMarshaller
constructor
Create a new marshaller, setting the current packet to the empty packet.
-
#num_align(n, a) ⇒ Object
Round n up to the specified power of two, a.
-
#struct ⇒ Object
Align and allow for appending struct fields.
Constructor Details
#initialize(offset = 0) ⇒ PacketMarshaller
Create a new marshaller, setting the current packet to the empty packet.
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# File 'lib/dbus/marshall.rb', line 241 def initialize(offset = 0) @packet = "" @offset = offset # for correct alignment of nested marshallers end |
Instance Attribute Details
#packet ⇒ Object (readonly)
The current or result packet. FIXME: allow access only when marshalling is finished
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# File 'lib/dbus/marshall.rb', line 237 def packet @packet end |
Class Method Details
.make_variant(value) ⇒ Object
Make a [signature, value] pair for a variant
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# File 'lib/dbus/marshall.rb', line 403 def self.make_variant(value) # TODO: mix in _make_variant to String, Integer... if value == true ["b", true] elsif value == false ["b", false] elsif value.nil? ["b", nil] elsif value.is_a? Float ["d", value] elsif value.is_a? Symbol ["s", value.to_s] elsif value.is_a? Array ["av", value.map { |i| make_variant(i) }] elsif value.is_a? Hash h = {} value.each_key { |k| h[k] = make_variant(value[k]) } ["a{sv}", h] elsif value.respond_to? :to_str ["s", value.to_str] elsif value.respond_to? :to_int i = value.to_int if -2_147_483_648 <= i && i < 2_147_483_648 ["i", i] else ["x", i] end end end |
Instance Method Details
#align(a) ⇒ Object
Align the buffer with NULL (0) bytes on a byte length of a.
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# File 'lib/dbus/marshall.rb', line 258 def align(a) @packet = @packet.ljust(num_align(@offset + @packet.bytesize, a) - @offset, 0.chr) end |
#append(type, val) ⇒ Object
Append a value val to the packet based on its type.
Host native endianness is used, declared in Message#marshall
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# File 'lib/dbus/marshall.rb', line 297 def append(type, val) raise TypeException, "Cannot send nil" if val.nil? type = type.chr if type.is_a?(Integer) type = Type::Parser.new(type).parse[0] if type.is_a?(String) case type.sigtype when Type::BYTE @packet += val.chr when Type::UINT32, Type::UNIX_FD align(4) @packet += [val].pack("L") when Type::UINT64 align(8) @packet += [val].pack("Q") when Type::INT64 align(8) @packet += [val].pack("q") when Type::INT32 align(4) @packet += [val].pack("l") when Type::UINT16 align(2) @packet += [val].pack("S") when Type::INT16 align(2) @packet += [val].pack("s") when Type::DOUBLE align(8) @packet += [val].pack("d") when Type::BOOLEAN align(4) @packet += if val [1].pack("L") else [0].pack("L") end when Type::OBJECT_PATH append_string(val) when Type::STRING append_string(val) when Type::SIGNATURE append_signature(val) when Type::VARIANT vartype = nil if val.is_a?(Array) && val.size == 2 if val[0].is_a?(DBus::Type::Type) vartype, vardata = val elsif val[0].is_a?(String) begin parsed = Type::Parser.new(val[0]).parse vartype = parsed[0] if parsed.size == 1 vardata = val[1] rescue Type::SignatureException # no assignment end end end if vartype.nil? vartype, vardata = PacketMarshaller.make_variant(val) vartype = Type::Parser.new(vartype).parse[0] end append_signature(vartype.to_s) align(vartype.alignment) sub = PacketMarshaller.new(@offset + @packet.bytesize) sub.append(vartype, vardata) @packet += sub.packet when Type::ARRAY if val.is_a?(Hash) raise TypeException, "Expected an Array but got a Hash" if type.child.sigtype != Type::DICT_ENTRY # Damn ruby rocks here val = val.to_a end # If string is recieved and ay is expected, explode the string if val.is_a?(String) && type.child.sigtype == Type::BYTE val = val.bytes end if !val.is_a?(Enumerable) raise TypeException, "Expected an Enumerable of #{type.child.inspect} but got a #{val.class}" end array(type.child) do val.each do |elem| append(type.child, elem) end end when Type::STRUCT, Type::DICT_ENTRY # TODO: use duck typing, val.respond_to? raise TypeException, "Struct/DE expects an Array" if !val.is_a?(Array) if type.sigtype == Type::DICT_ENTRY && val.size != 2 raise TypeException, "Dict entry expects a pair" end if type.members.size != val.size raise TypeException, "Struct/DE has #{val.size} elements but type info for #{type.members.size}" end struct do type.members.zip(val).each do |t, v| append(t, v) end end else raise NotImplementedError, "sigtype: #{type.sigtype} (#{type.sigtype.chr})" end end |
#append_signature(str) ⇒ Object
Append the the signature signature itself to the packet.
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# File 'lib/dbus/marshall.rb', line 269 def append_signature(str) @packet += str.bytesize.chr + str + "\0" end |
#append_string(str) ⇒ Object
Append the the string str itself to the packet.
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# File 'lib/dbus/marshall.rb', line 263 def append_string(str) align(4) @packet += [str.bytesize].pack("L") + [str].pack("Z*") end |
#array(type) ⇒ Object
Append the array type type to the packet and allow for appending the child elements.
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# File 'lib/dbus/marshall.rb', line 275 def array(type) # Thanks to Peter Rullmann for this line align(4) sizeidx = @packet.bytesize @packet += "ABCD" align(type.alignment) contentidx = @packet.bytesize yield sz = @packet.bytesize - contentidx raise InvalidPacketException if sz > 67_108_864 @packet[sizeidx...sizeidx + 4] = [sz].pack("L") end |
#num_align(n, a) ⇒ Object
Round n up to the specified power of two, a
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# File 'lib/dbus/marshall.rb', line 247 def num_align(n, a) case a when 1, 2, 4, 8 bits = a - 1 n + bits & ~bits else raise "Unsupported alignment" end end |
#struct ⇒ Object
Align and allow for appending struct fields.
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# File 'lib/dbus/marshall.rb', line 289 def struct align(8) yield end |