caf::message Class Reference

Describes a fixed-length, copy-on-write, type-erased tuple with elements of any type. More...

#include <message.hpp>

Inheritance diagram for caf::message:

Classes
struct	cli_arg
	Stores the name of a command line option ("<long name>[,<short name>]") along with a description and a callback. More...
struct	cli_res
	Stores the result of message::extract_opts. More...

Public Types
using	raw_ptr = detail::message_data *
	Raw pointer to content.
using	data_ptr = detail::message_data::cow_ptr
	Copy-on-write pointer to content.
using	help_factory = std::function< std::string(const std::vector< cli_arg > &)>
	Function object for generating CLI argument help text.

Public Member Functions
	message (none_t) noexcept
	message (const message &) noexcept=default
message &	operator= (const message &) noexcept=default
	message (message &&) noexcept
message &	operator= (message &&) noexcept
	message (data_ptr ptr) noexcept
void *	get_mutable (size_t p) override
	Returns a mutable pointer to the element at position pos.
error	load (size_t pos, deserializer &source) override
	Load the content for the element at position pos from source.
size_t	size () const noexcept override
	Returns the size of this tuple.
uint32_t	type_token () const noexcept override
	Returns a type hint for the element types.
rtti_pair	type (size_t pos) const noexcept override
	Returns the type number and std::type_info object for the element at position pos.
const void *	get (size_t pos) const noexcept override
	Returns the element at position pos.
std::string	stringify (size_t pos) const override
	Returns a string representation of the element at position pos.
type_erased_value_ptr	copy (size_t pos) const override
	Returns a copy of the element at position pos.
error	save (size_t pos, serializer &sink) const override
	Saves the element at position pos to sink.
bool	shared () const noexcept override
	Returns whether multiple references to this tuple exist. More...
error	load (deserializer &source) override
	Load the content for the tuple from source.
error	save (serializer &sink) const override
	Saves the content of the tuple to sink.
message &	operator+= (const message &x)
	Concatenates *this and x.
optional< message >	apply (message_handler handler)
	Returns handler(*this).
void	force_unshare ()
	Forces the message to copy its content if there are more than one references to the content.
data_ptr &	vals ()
	Returns a mutable reference to the content. More...
void	swap (message &other) noexcept
	Exchanges content of this and other.
void	reset (raw_ptr new_ptr=nullptr, bool add_ref=true) noexcept
	Assigns new content.
message	drop (size_t n) const
	Creates a new message with all but the first n values.
message	drop_right (size_t n) const
	Creates a new message with all but the last n values.
message	slice (size_t pos, size_t n) const
	Creates a new message of size n starting at the element at position p.
message	extract (message_handler handler) const
	Filters this message by applying slices of it to handler and returns the remaining elements of this operation. More...
cli_res	extract_opts (std::vector< cli_arg > xs, const help_factory &f=nullptr, bool no_help=false) const
	A simplistic interface for using extract to parse command line options. More...
const void *	at (size_t p) const noexcept
	Returns a const pointer to the element at position p.
const data_ptr &	vals () const noexcept
	Returns a reference to the content.
const data_ptr &	cvals () const noexcept
	Returns a reference to the content.
message	take (size_t n) const
	Returns the size of this message. More...
message	take_right (size_t n) const
	Creates a new message from the last n values.
Public Member Functions inherited from caf::type_erased_tuple
	type_erased_tuple (const type_erased_tuple &)=default
type_erased_tuple &	operator= (const type_erased_tuple &)=default
bool	empty () const
	Returns size() == 0.
std::string	stringify () const
	Returns a string representation of the tuple.
bool	matches (size_t pos, uint16_t nr, const std::type_info *ptr) const noexcept
	Checks whether the type of the stored value at position pos matches type number n and run-time type information p.
uint16_t	type_nr (size_t pos) const noexcept
	Returns the type number for the element at position pos.
bool	matches (size_t pos, const rtti_pair &rtti) const noexcept
	Checks whether the type of the stored value matches rtti.
template<class T >
const T &	get_as (size_t pos) const
	Convenience function for *reinterpret_cast<const T*>(get()).
template<class T , size_t Pos>
const T &	get_as (typed_index< T, Pos >) const
template<class... Ts, long... Is>
std::tuple< const Ts &... >	get_as_tuple (detail::type_list< Ts... >, detail::int_list< Is... >) const
template<class... Ts>
std::tuple< const Ts &... >	get_as_tuple () const
template<class T >
T &	get_mutable_as (size_t pos)
	Convenience function for *reinterpret_cast<T*>(get_mutable()).
template<class T >
T	move_if_unshared (size_t pos)
	Convenience function for moving a value out of the tuple if it is unshared. More...
template<class T >
bool	match_element (size_t pos) const noexcept
	Returns true if the element at pos matches T.
template<class... Ts>
bool	match_elements () const noexcept
	Returns true if the pattern Ts... matches the content of this tuple.
template<class F >
auto	apply (F fun) -> optional< typename detail::get_callable_trait< F >::result_type >

Static Public Member Functions
template<class... Ts>
static message	concat (const Ts &... xs)
	Creates a new message by concatenating xs....
static message	copy (const type_erased_tuple &xs)
	Creates a new message by copying all elements in a type-erased tuple.
Static Public Member Functions inherited from caf::type_erased_tuple
template<class T , size_t Pos>
static constexpr typed_index< T, Pos >	make_typed_index ()

Related Functions
(Note that these are not member functions.)
template<class T , class... Ts>
std::enable_if< !std::is_same< message, typename std::decay< T >::type >::value||(sizeof...(Ts) >) message::type	make_message (T &&x, Ts &&... xs)
	Returns a new message containing the values (x, xs...).
message	make_message (message other)
	Returns a copy of other.
message	make_message ()
	Returns an empty message.
error	inspect (serializer &sink, message &msg)
error	inspect (deserializer &source, message &msg)
std::string	to_string (const message &msg)
message	operator+ (const message &lhs, const message &rhs)
Related Functions inherited from caf::type_erased_tuple
template<class... Ts>
detail::type_erased_tuple_view< Ts... >	make_type_erased_tuple_view (Ts &... xs)
template<class Processor >
std::enable_if< Processor::reads_state >::type	serialize (Processor &proc, type_erased_tuple &x)
template<class Processor >
std::enable_if< Processor::writes_state >::type	serialize (Processor &proc, type_erased_tuple &x)
std::string	to_string (const type_erased_tuple &x)

Detailed Description

Describes a fixed-length, copy-on-write, type-erased tuple with elements of any type.

Member Function Documentation

extract()

message caf::message::extract

(

message_handler

handler

)

const

Filters this message by applying slices of it to handler and returns the remaining elements of this operation.

Slices are generated in the sequence [0, size), [0, size-1), ... , [1, size-1), ..., [size-1, size). Whenever a slice matches, it is removed from the message and the next slice starts at the same index on the reduced message.

For example:

auto msg = make_message(1, 2.f, 3.f, 4);
// extract float and integer pairs
auto msg2 = msg.extract({
  [](float, float) { },
  [](int, int) { }
});
assert(msg2 == make_message(1, 4));

Step-by-step explanation:

• Slice 1: (1, 2.f, 3.f, 4), no match
• Slice 2: (1, 2.f, 3.f), no match
• Slice 3: (1, 2.f), no match
• Slice 4: (1), no match
• Slice 5: (2.f, 3.f, 4), no match
• Slice 6: (2.f, 3.f), match; new message is (1, 4)
• Slice 7: (4), no match

Slice 7 is (4), i.e., does not contain the first element, because the match on slice 6 occurred at index position 1. The function extract iterates a message only once, from left to right.

extract_opts()

cli_res caf::message::extract_opts	(	std::vector< cli_arg >	xs,
		const help_factory &	f = nullptr,
		bool	no_help = false
	)		const

A simplistic interface for using extract to parse command line options.

Usage example:

int main(int argc, char** argv) {
  uint16_t port;
  string host = "localhost";
  auto res = message_builder(argv + 1, argv + argc).extract_opts({
    {"port,p", "set port", port},
    {"host,H", "set host (default: localhost)", host},
    {"verbose,v", "enable verbose mode"}
  });
  if (!res.error.empty()) {
    cerr << res.error << endl;
    return 1;
  }
  if (res.opts.count("help") > 0) {
    // CLI arguments contained "-h", "--help", or "-?" (builtin);
    cout << res.helptext << endl;
    return 0;
  }
  if (!res.remainder.empty()) {
    // ... extract did not consume all CLI arguments ...
  }
  if (res.opts.count("verbose") > 0) {
    // ... enable verbose mode ...
  }
  // ...
}

Parameters

xs	List of argument descriptors.
f	Optional factory function to generate help text (overrides the default generator).
no_help	Suppress generation of default-generated help option.

Returns

A struct containing remainder (i.e. unmatched elements), a set containing the names of all used arguments, and the generated help text.

Exceptions

std::invalid_argument

if no name or more than one long name is set

shared()

bool caf::message::shared ( ) const

overridevirtualnoexcept

Returns whether multiple references to this tuple exist.

The default implementation returns false.

Reimplemented from caf::type_erased_tuple.

take()

message caf::message::take

(

size_t

n

)

const

Returns the size of this message.

Creates a new message from the first n values.

vals()

data_ptr& caf::message::vals

(

)

Returns a mutable reference to the content.

Callers are responsible for unsharing content if necessary.

---

The documentation for this class was generated from the following files:

• /build/actor-framework-GBadMI/actor-framework-0.17.6/libcaf_core/caf/message.hpp
• /build/actor-framework-GBadMI/actor-framework-0.17.6/libcaf_core/caf/make_message.hpp