libraries/eosiolib/contracts/eosio/dispatcher.hpp

Namespaces

Name
eosio

Defines

	Name
	EOSIO_DISPATCH(TYPE, MEMBERS)

Macros Documentation

define EOSIO_DISPATCH

#define EOSIO_DISPATCH(
    TYPE,
    MEMBERS
)
extern "C" { \
   [[eosio::wasm_entry]] \
   void apply( uint64_t receiver, uint64_t code, uint64_t action ) { \
      if( code == receiver ) { \
         switch( action ) { \
            EOSIO_DISPATCH_HELPER( TYPE, MEMBERS ) \
         } \
         /* does not allow destructor of thiscontract to run: eosio_exit(0); */ \
      } \
   } \
} \

Parameters:

• TYPE - The class name of the contract
• MEMBERS - The sequence of available actions supported by this contract

Note: To be able to use this macro, the contract needs to be derived from eosio::contract

Convenient macro to create contract apply handler

Example:

EOSIO_DISPATCH( eosio::bios, (setpriv)(setalimits)(setglimits)(setprods)(reqauth) )

Source code

#pragma once
#include "action.hpp"

#include <boost/fusion/adapted/std_tuple.hpp>
#include <boost/fusion/include/std_tuple.hpp>

#include <boost/mp11/tuple.hpp>

namespace eosio {


   template<typename Contract, typename FirstAction>
   bool dispatch( uint64_t code, uint64_t act ) {
      if( code == FirstAction::get_account() && FirstAction::get_name() == act ) {
         Contract().on( unpack_action_data<FirstAction>() );
         return true;
      }
      return false;
   }


   template<typename Contract, typename FirstAction, typename SecondAction, typename... Actions>
   bool dispatch( uint64_t code, uint64_t act ) {
      if( code == FirstAction::get_account() && FirstAction::get_name() == act ) {
         Contract().on( unpack_action_data<FirstAction>() );
         return true;
      }
      return eosio::dispatch<Contract,SecondAction,Actions...>( code, act );
   }




   template<typename T, typename... Args>
   bool execute_action( name self, name code, void (T::*func)(Args...)  ) {
      size_t size = action_data_size();

      //using malloc/free here potentially is not exception-safe, although WASM doesn't support exceptions
      constexpr size_t max_stack_buffer_size = 512;
      void* buffer = nullptr;
      if( size > 0 ) {
         buffer = max_stack_buffer_size < size ? malloc(size) : alloca(size);
         read_action_data( buffer, size );
      }

      std::tuple<std::decay_t<Args>...> args;
      datastream<const char*> ds((char*)buffer, size);
      ds >> args;

      T inst(self, code, ds);

      auto f2 = [&]( auto... a ){
         ((&inst)->*func)( a... );
      };

      boost::mp11::tuple_apply( f2, args );
      if ( max_stack_buffer_size < size ) {
         free(buffer);
      }
      return true;
   }


 // Helper macro for EOSIO_DISPATCH_INTERNAL
 #define EOSIO_DISPATCH_INTERNAL( r, OP, elem ) \
    case eosio::name( BOOST_PP_STRINGIZE(elem) ).value: \
       eosio::execute_action( eosio::name(receiver), eosio::name(code), &OP::elem ); \
       break;

 // Helper macro for EOSIO_DISPATCH
 #define EOSIO_DISPATCH_HELPER( TYPE,  MEMBERS ) \
    BOOST_PP_SEQ_FOR_EACH( EOSIO_DISPATCH_INTERNAL, TYPE, MEMBERS )


#define EOSIO_DISPATCH( TYPE, MEMBERS ) \
extern "C" { \
   [[eosio::wasm_entry]] \
   void apply( uint64_t receiver, uint64_t code, uint64_t action ) { \
      if( code == receiver ) { \
         switch( action ) { \
            EOSIO_DISPATCH_HELPER( TYPE, MEMBERS ) \
         } \
         /* does not allow destructor of thiscontract to run: eosio_exit(0); */ \
      } \
   } \
} \

}

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Updated on 2022-12-05 at 15:38:08 +0000