LibXR::Topic::Callback Class Reference

每次发布时直接执行函数的订阅句柄 / Subscription handle that runs a function on each publish More...

#include <callback.hpp>

Collaboration diagram for LibXR::Topic::Callback:

Data Structures
struct	BlockHeader
	回调句柄真正指向的那块数据的公共头 / Common header of the data block actually pointed to by one callback handle More...
struct	Factory
	看回调有几个参数，决定分配哪种回调块 / Choose which callback block to allocate from the callback parameter count More...
struct	Factory< Function, BoundArg, 3 >
	三参数回调块工厂 / Factory for three-argument callback blocks More...
struct	Factory< Function, BoundArg, 4 >
	四参数回调块工厂 / Factory for four-argument callback blocks More...
struct	FunctionTraits
	把一个无捕获回调函数拆成返回类型和参数类型 / Split one callback function without captures into its return type and parameter types More...
struct	FunctionTraits< Return(*)(Args...)>
struct	MessageViewTraits
	判断某个参数是否为 MessageView<T> / Tell whether one argument is MessageView<T> More...
struct	MessageViewTraits< MessageView< Data > >
struct	PayloadOnlyBlock
	只转发负载的回调块 / Callback block that forwards only the payload More...
struct	TimestampPayloadBlock
	同时转发时间戳和负载的回调块 / Callback block that forwards both timestamp and payload More...

Public Member Functions
	Callback ()=default
	构造一个空回调句柄 / Construct one empty callback handle
	Callback (const Callback &other)=default
	拷贝构造回调句柄 / Copy-construct one callback handle
Callback &	operator= (const Callback &other)=default
	拷贝赋值回调句柄 / Copy-assign one callback handle
void	Run (bool in_isr, MicrosecondTimestamp timestamp, void *payload_addr, size_t payload_size) const
	执行回调 / Run the callback
TypeID::ID	PayloadTypeID () const
	读取这个回调句柄期望的 payload 类型标识 / Read the payload type ID expected by this callback handle
bool	IsRawPayloadView () const
	判断该回调是否按 raw payload 视图接收消息 / Tell whether this callback receives messages as a raw payload view

Static Public Member Functions
template<typename BoundArg , typename Callable >
static Callback	Create (Callable fun, BoundArg arg)
	创建一个回调订阅句柄 / Create a callback subscription handle

Private Types
template<typename T >
using	RemoveCVRef = std::remove_cv_t<std::remove_reference_t<T>>
	去掉引用和 cv 限定后的规范类型 / Canonical type after removing reference and cv qualifiers

Private Member Functions
	Callback (BlockHeader *block)
	用指定执行块构造回调句柄 / Construct one callback handle from the given execution block

Static Private Member Functions
template<typename PayloadArg >
static TypeID::ID	PayloadTypeID ()
	取回调 payload 参数对应的精确类型标识 / Get the exact type ID expected by one callback payload argument
template<typename PayloadArg >
static constexpr bool	AcceptsRawPayload ()
	回调 payload 参数是否是 raw 字节视图 / Whether the callback payload argument is a raw byte view
template<typename Function , typename BoundArg , typename PayloadArg >
static void	InvokePayload (Function fun, BoundArg &arg, bool in_isr, MicrosecondTimestamp timestamp, void *payload_addr, size_t payload_size)
	按回调声明的参数形式，把当前消息拼成实参再调函数 / Build the actual call arguments from the current message in the form declared by the callback, then invoke it
static void	EmptyRun (const BlockHeader *header, bool in_isr, MicrosecondTimestamp timestamp, void *payload_addr, size_t payload_size)
	空回调块的执行函数 / Execution function of the empty callback block

Private Attributes
BlockHeader *	block_ = &empty_block_

Static Private Attributes
template<typename T >
static constexpr bool	IS_MESSAGE_VIEW
	是否为带时间戳的类型化消息视图参数 / Whether one callback payload argument is a timestamped typed message view
template<typename T >
static constexpr bool	IS_RAW_DATA_VIEW
	是否为只读 raw payload 视图参数 / Whether one callback payload argument is a read-only raw payload view
template<typename T >
static constexpr bool	IS_TYPED_DATA
	是否把 payload 直接当成一个对象接收 / Whether one callback payload argument receives the payload directly as one object
template<typename T >
static constexpr bool	IS_CALLBACK_PAYLOAD
	是否是回调接口允许的 payload 参数写法 / Whether one payload argument form is accepted by this callback interface
template<typename T >
static constexpr bool	IS_MUTABLE_MESSAGE_VIEW_REF
	是否错误地使用了可变 MessageView<T>& / Whether one payload argument is an invalid mutable MessageView<T>&
static BlockHeader	empty_block_

Detailed Description

每次发布时直接执行函数的订阅句柄 / Subscription handle that runs a function on each publish

每次发布时直接执行函数的回调订阅句柄 / Callback subscription handle that runs a function on each publish

Definition at line 15 of file callback.hpp.

Member Typedef Documentation

RemoveCVRef

template<typename T >

using LibXR::Topic::Callback::RemoveCVRef = std::remove_cv_t<std::remove_reference_t<T>>

private

去掉引用和 cv 限定后的规范类型 / Canonical type after removing reference and cv qualifiers

Template Parameters

T	待规范化的类型 / Type to normalize

Definition at line 82 of file callback.hpp.

Constructor & Destructor Documentation

Callback() [1/2]

LibXR::Topic::Callback::Callback ( const Callback & other )

default

拷贝构造回调句柄 / Copy-construct one callback handle

Parameters

other

被拷贝的回调句柄 / Callback handle to copy from

Note

这里只复制句柄本身，不复制底层回调块；两个句柄会指向同一块回调数据 / This copies only the handle itself, not the underlying callback block; both handles point to the same callback data block

Callback() [2/2]

LibXR::Topic::Callback::Callback ( BlockHeader * block )

inlineexplicitprivate

用指定执行块构造回调句柄 / Construct one callback handle from the given execution block

Parameters

block

回调块公共头；为空时回退到静态空块 / Callback block header; falls back to the shared empty block when null

Definition at line 554 of file callback.hpp.

: block_(block ? block : &empty_block_) {}

Member Function Documentation

AcceptsRawPayload()

template<typename PayloadArg >

static constexpr bool LibXR::Topic::Callback::AcceptsRawPayload ( )

inlinestaticconstexprprivate

回调 payload 参数是否是 raw 字节视图 / Whether the callback payload argument is a raw byte view

Template Parameters

PayloadArg

回调 payload 参数类型 / Callback payload argument type

Returns

是 raw 字节视图则返回 true / Returns true for raw byte view payloads

Definition at line 201 of file callback.hpp.

  {
    return IS_RAW_DATA_VIEW<PayloadArg>;
  }

Create()

template<typename BoundArg , typename Callable >

static Callback LibXR::Topic::Callback::Create ( Callable fun, BoundArg arg )

inlinestaticnodiscard

创建一个回调订阅句柄 / Create a callback subscription handle

Template Parameters

BoundArg	绑定参数类型 / Bound argument type
Callable	回调可调用对象类型 / Callback callable type

Parameters

fun	捕获为空的回调函数 / Capture-free callback function
arg	绑定到回调的参数 / Argument bound into the callback

Returns

创建后的回调订阅句柄 / Returns the created callback subscription handle

Note

这里会把 arg 拷进新分配的回调块里；之后回调执行读写的就是这份块内副本 / This copies arg into the newly allocated callback block; later callback execution reads or writes that stored copy

Definition at line 508 of file callback.hpp.

  {
    using Function = decltype(+std::declval<Callable>());
    using Traits = FunctionTraits<Function>;
    static_assert(Traits::ARITY == 3 || Traits::ARITY == 4,
                  "LibXR::Topic::Callback::Create expects a capture-free callable "
                  "with bool and bound-argument parameters.");
    return Callback(
        Factory<Function, BoundArg, Traits::ARITY>::Create(+fun, std::move(arg)));
  }

EmptyRun()

static void LibXR::Topic::Callback::EmptyRun ( const BlockHeader * header, bool in_isr, MicrosecondTimestamp timestamp, void * payload_addr, size_t payload_size )

inlinestaticprivate

空回调块的执行函数 / Execution function of the empty callback block

Parameters

header	空块头指针 / Empty block header pointer
in_isr	当前是否处于中断上下文 / Whether the current path runs in ISR context
timestamp	当前消息时间戳 / Current message timestamp
payload_addr	当前消息 payload 对象地址 / Address of the current payload object

Definition at line 456 of file callback.hpp.

  {
    UNUSED(header);
    UNUSED(in_isr);
    UNUSED(timestamp);
    UNUSED(payload_addr);
    UNUSED(payload_size);
  }

InvokePayload()

template<typename Function , typename BoundArg , typename PayloadArg >

static void LibXR::Topic::Callback::InvokePayload ( Function fun, BoundArg & arg, bool in_isr, MicrosecondTimestamp timestamp, void * payload_addr, size_t payload_size )

inlinestaticprivate

按回调声明的参数形式，把当前消息拼成实参再调函数 / Build the actual call arguments from the current message in the form declared by the callback, then invoke it

Template Parameters

Function	回调函数类型 / Callback function type
BoundArg	绑定参数类型 / Bound argument type
PayloadArg	负载参数类型 / Payload argument type

Parameters

fun	回调函数 / Callback function
arg	绑定参数 / Bound argument
in_isr	当前是否处于中断上下文 / Whether the current path runs in ISR context
timestamp	当前消息时间戳 / Current message timestamp
payload_addr	当前消息 payload 对象地址 / Address of the current payload object

Definition at line 221 of file callback.hpp.

  {
    if constexpr (std::same_as<RemoveCVRef<PayloadArg>, ConstRawData>)
    {
      ConstRawData raw_payload{payload_addr, payload_size};
      fun(in_isr, arg, raw_payload);
    }
    else if constexpr (std::same_as<RemoveCVRef<PayloadArg>, RawMessageView>)
    {
      RawMessageView raw_message{timestamp, ConstRawData{payload_addr, payload_size}};
      fun(in_isr, arg, raw_message);
    }
    else if constexpr (IS_MESSAGE_VIEW<PayloadArg>)
    {
      using View = MessageViewTraits<RemoveCVRef<PayloadArg>>;
      using Data = typename View::DataType;
      fun(in_isr, arg,
          MessageView<Data>{timestamp, reinterpret_cast<Data*>(payload_addr)});
    }
    else
    {
      using Data = RemoveCVRef<PayloadArg>;
      fun(in_isr, arg, *reinterpret_cast<Data*>(payload_addr));
    }
  }

IsRawPayloadView()

bool LibXR::Topic::Callback::IsRawPayloadView ( ) const

inline

判断该回调是否按 raw payload 视图接收消息 / Tell whether this callback receives messages as a raw payload view

Returns

是 raw payload 视图回调则返回 true / Returns true for raw payload view callbacks

Definition at line 545 of file callback.hpp.

{ return block_->accepts_raw_payload; }

operator=()

Callback & LibXR::Topic::Callback::operator= ( const Callback & other )

default

拷贝赋值回调句柄 / Copy-assign one callback handle

Parameters

other

被拷贝的回调句柄 / Callback handle to copy from

Returns

当前回调句柄 / Returns the current callback handle

Note

这里只复制句柄本身，不复制底层回调块；赋值后两个句柄会指向同一块回调数据 / This copies only the handle itself, not the underlying callback block; after assignment both handles point to the same callback data block

PayloadTypeID() [1/2]

template<typename PayloadArg >

static TypeID::ID LibXR::Topic::Callback::PayloadTypeID ( )

inlinestaticprivate

取回调 payload 参数对应的精确类型标识 / Get the exact type ID expected by one callback payload argument

Template Parameters

PayloadArg

回调 payload 参数类型 / Callback payload argument type

Returns

对应的精确类型标识 / Exact type ID expected by this callback payload argument

Definition at line 170 of file callback.hpp.

  {
    static_assert(!IS_MUTABLE_MESSAGE_VIEW_REF<PayloadArg>,
                  "LibXR::Topic::Callback does not accept MessageView<T>&; "
                  "use MessageView<T> or const MessageView<T>& instead.");
 
    if constexpr (IS_RAW_DATA_VIEW<PayloadArg>)
    {
      return nullptr;
    }
    else if constexpr (IS_MESSAGE_VIEW<PayloadArg>)
    {
      using View = MessageViewTraits<RemoveCVRef<PayloadArg>>;
      return TypeID::GetID<typename View::DataType>();
    }
    else
    {
      static_assert(IS_TYPED_DATA<PayloadArg>,
                    "LibXR::Topic::Callback payload must be Topic::MessageView<T>, "
                    "Topic::RawMessageView, ConstRawData, T, T&, or const T&.");
      return TypeID::GetID<RemoveCVRef<PayloadArg>>();
    }
  }

PayloadTypeID() [2/2]

TypeID::ID LibXR::Topic::Callback::PayloadTypeID ( ) const

inline

读取这个回调句柄期望的 payload 类型标识 / Read the payload type ID expected by this callback handle

Returns

payload 类型标识 / Payload type ID

Definition at line 537 of file callback.hpp.

{ return block_->payload_type_id; }

Run()

void LibXR::Topic::Callback::Run ( bool in_isr, MicrosecondTimestamp timestamp, void * payload_addr, size_t payload_size ) const

inline

执行回调 / Run the callback

Parameters

in_isr	当前是否处于中断上下文 / Whether the current path runs in ISR context
timestamp	当前消息时间戳 / Current message timestamp
payload_addr	当前消息 payload 对象地址 / Address of the current payload object

Definition at line 526 of file callback.hpp.

  {
    block_->run(block_, in_isr, timestamp, payload_addr, payload_size);
  }

Field Documentation

block_

BlockHeader* LibXR::Topic::Callback::block_ = &empty_block_

private

当前回调句柄绑定的执行块。Execution block bound to the current callback handle.

Definition at line 556 of file callback.hpp.

empty_block_

BlockHeader LibXR::Topic::Callback::empty_block_

inlinestaticprivate

Initial value:

{
      &EmptyRun, nullptr, false}

空回调句柄共用的静态空执行块。Shared static empty execution block used by empty callback handles.

Definition at line 467 of file callback.hpp.

                                        {
      &EmptyRun, nullptr, false};  

IS_CALLBACK_PAYLOAD

template<typename T >

bool LibXR::Topic::Callback::IS_CALLBACK_PAYLOAD

staticconstexprprivate

Initial value:

=
      IS_MESSAGE_VIEW<T> || IS_RAW_DATA_VIEW<T> ||
      IS_TYPED_DATA<T>

是否是回调接口允许的 payload 参数写法 / Whether one payload argument form is accepted by this callback interface

Template Parameters

T	待判断的参数类型 / Argument type to inspect 是否是这个回调接口允许的负载参数写法。Whether this callback interface accepts this payload argument form.

Definition at line 122 of file callback.hpp.

IS_MESSAGE_VIEW

template<typename T >

bool LibXR::Topic::Callback::IS_MESSAGE_VIEW

staticconstexprprivate

Initial value:

= MessageViewTraits<
      RemoveCVRef<T>>::VALUE

是否为带时间戳的类型化消息视图参数 / Whether one callback payload argument is a timestamped typed message view

Template Parameters

T	待判断的参数类型 / Argument type to inspect 是否为带时间戳的类型化消息视图参数。Whether the argument is a timestamped typed message view.

Definition at line 90 of file callback.hpp.

IS_MUTABLE_MESSAGE_VIEW_REF

template<typename T >

bool LibXR::Topic::Callback::IS_MUTABLE_MESSAGE_VIEW_REF

staticconstexprprivate

Initial value:

=
      IS_MESSAGE_VIEW<T> && std::is_lvalue_reference_v<T> &&
      !std::is_const_v<std::remove_reference_t<T>>

是否错误地使用了可变 MessageView<T>& / Whether one payload argument is an invalid mutable MessageView<T>&

Template Parameters

T	待判断的参数类型 / Argument type to inspect

Definition at line 133 of file callback.hpp.

IS_RAW_DATA_VIEW

template<typename T >

bool LibXR::Topic::Callback::IS_RAW_DATA_VIEW

staticconstexprprivate

Initial value:

= std::same_as<RemoveCVRef<T>, ConstRawData> ||
                                           std::same_as<RemoveCVRef<T>, RawMessageView>

是否为只读 raw payload 视图参数 / Whether one callback payload argument is a read-only raw payload view

Template Parameters

T	待判断的参数类型 / Argument type to inspect

Definition at line 101 of file callback.hpp.

IS_TYPED_DATA

template<typename T >

bool LibXR::Topic::Callback::IS_TYPED_DATA

staticconstexprprivate

Initial value:

=
      !IS_MESSAGE_VIEW<T> && !IS_RAW_DATA_VIEW<T> &&
      TopicPayload<RemoveCVRef<T>>

是否把 payload 直接当成一个对象接收 / Whether one callback payload argument receives the payload directly as one object

Template Parameters

T	待判断的参数类型 / Argument type to inspect 是否把负载直接当成一个对象来接收。Whether the payload is received directly as one typed object.

Definition at line 110 of file callback.hpp.

---

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

• src/middleware/message/subscriber/callback.hpp