eosio.cdt_OldvsNew.md

Differences between Version 1.2.x and Version 1.3.x

eosiolib C API

• Removed the following typedefs to uint64_t:
  • account_name
  • permission_name
  • scope_name
  • table_name
  • action_name
• Added a uint64_t typedef called capi_name to replace the removed typedefs above:
  • These have been replaced by capi_name and as a practice should not be used when writing C++ contract code. Instead, the new version of the eosio::name type from the eosiolib C++ API should be used to replace these instances. This decision was made because of bad implicit casting issues with uint64_t and the new pattern should allow for better type safety.
• Removed symbol_name typedef:
  • This has no C equivalent to replace it. When writing C++ contract code, the eosio::symbol_code struct should be used instead. As with the previously mentioned named types, this was removed and replaced with eosio::symbol_code to allow for better type safety in contracts. To use a symbol, i.e. symbol name and precision, use the eosio::symbol class.
• Removed time and weight_type typedefs.
• Removed the transaction_id_type and block_id_type typedefs.
• Removed the account_permission struct.
• Renamed the following typedefs:
  • checksum160 -> capi_checksum160
  • checksum256 -> capi_checksum256
  • checksum512 -> capi_checksum512
  • public_key -> capi_public_key
  • signature -> capi_signature
• Removed the non-existent intrinsics declarations require_write_lock and require_read_lock.

eosiolib C++ API

• Removed eosiolib/vector.hpp:
  • Removed alias eosio::vector and typedef bytes.
  • Going forward contract writers should include <vector> from the STL and use std::vector<char> instead of bytes.
• Removed eosiolib/types.hpp.
• Removed eosiolib/optional.hpp. Use std::optional as a replacement.
• Removed eosiolib/core_symbol.hpp. The contract writer should explicitly specify the symbol.
• Added eosiolib/name.hpp.

eosiolib/types.hpp

• Moved the typedef eosio::extensions_types to eosiolib/transaction.hpp.
• Removed comparison functions for checksum structs.
• Removal of eosio::char_to_symbol, eosio::string_to_name, eosio::name_suffix functions
• Removal of the N macro. The ""_n operator or the name constructor should be used as a type safe replacement. Example: N(foo) -> "foo"_n, or N(foo) -> name("foo").
• Moved eosio::name struct definition and ""_n operator to eosiolib/name.hpp.

eosiolib/name.hpp

• Removed implicit and explicit conversions to uint64_t.
• Added enum class eosio::name::raw which is implicitly converted from an eosio::name (used for template non-type parameters).
• Added bool conversion operator for conditionally testing if a name is empty.
• All constructors are now constexpr. These take either a uint64_t, an eosio::name::raw or a std::string_view.
• Added constexpr methods eosio::name::length and eosio::name::suffix.
• Added equivalence, inverted equivalence and less than operators to eosio::name.

eosiolib/symbol.hpp

• Removed eosio::symbol_type struct and replaced with eosio::symbol class.
• Added struct eosio::symbol_code:
  • Added two constexpr constructors that take either a raw uint64_t or an std::string_view.
  • Added constexpr methods is_valid, length and raw.
  • Added a print method.
  • Added bool conversion operator to test is symbol_code is empty.
• Removed eosio::string_to_symbol, eosio::is_valid_symbol, eosio::symbol_name_length functions.
• Removed the S macro. The symbol constructor should be used as a type safe replacement. Example: S(4,SYS) -> symbol(symbol_code("SYS"), 4) (or simply symbol("SYS", 4) as of v1.3.1).
• Added struct eosio::symbol:
  • Added three constexpr constructors that take either a raw uint64_t, symbol_code and a uint8_t precision or an std::string_view and a uint8_t precision.
  • Added constexpr methods is_valid, precision, code, and raw. These, respectively, check if the symbol is valid, get the uint8_t precision, get the symbol_code part of the symbol, and get the raw uint64_t representation of symbol.
  • Added equivalence, inverted equivalence and less than operators to eosio::symbol.
• Modified struct eosio::extended_symbol:
  • Restricted fields to private.
  • Added constexpr constructor that takes a eosio::symbol and an eosio::name.
  • Added constexpr methods get_symbol and get_contract.
  • Made existing comparison operators constexpr.

eosiolib/asset.hpp

• The main constructor now requires a int64_t (quantity) and eosio::symbol explicitly.
• The default constructor no longer initializes the instance to a valid zero quantity asset with a symbol equivalent to "core symbol". Instead the default constructed eosio::asset is a bit representation of all zeros (which will cause is_valid to fail) so that check is bypassed to allow for multi_index and datastream to work.
• Old contracts that use eosio::asset() should be changed to either use the core symbol of the specific chain they are targeting i.e. eosio::asset(0, symbol(symbol_code("SYS"),4)). To reduce writing symbol(symbol_code("SYS"),4) over and over, a constexpr function to return the symbol or constexpr global variable should be used.

eosiolib/contract.hpp

• The constructor for eosio::contract now takes an eosio::name for the receiver, an eosio::name for the code, and a eosio::datastream<const char*> for the datastream used for the contract. The last argument is for manually unpacking an action, see the section on eosio::ignore for a more indepth usage.

eosiolib/dispatcher.hpp

• Renamed the macro EOSIO_ABI to EOSIO_DISPATCH as this is more descriptive of what this macro actually does.
• Modified the definition of EOSIO_DISPATCH to work with the new constructor for eosio::contract.

eosiolib/multi_index.hpp

• The first template parameter for indexed_by now requires the argument be convertible to eosio::name::raw (replacing uint64_t).
• The first template parameter for multi_index now requires the argument be convertible to eosio::name::raw (replacing uint64_t).
• The constructor now takes an eosio::name type for the code (replacing uint64_t). Scope is still uint64_t.
• Various other replacements of uint64_t to eosio::name.

eosiolib/singleton.hpp

• The first template parameter for eosio::singleton now requires the argument be convertible to eosio::name::raw (replacing uint64_t).
• The constructor now takes an eosio::name type for the code.
• In the methods get_or_create and set, the argument bill_to_account is now of type eosio::name (replacing uint64_t).

eosiolib/action.hpp

• Added C++ function eosio::require_auth.
• Added C++ function eosio::has_auth.
• Added C++ function eosio::is_account.
• Redefined eosio::permission_level to use eosio::name in place of uint64_t.
• Removed the macro ACTION. (The identifier ACTION has been reused for another macro described below in the Macros section.)

eosiolib/permission.hpp

• The optional provided_keys argument of the function eosio::check_transaction_authorization is now of the type std::set<eosio::public_key> rather than the type std::set<capi_public_key>. C++ contract code should most likely be using the eosio::public_key struct (defined in "eosiolib/public_key.hpp") if they need to deal with EOSIO-compatible public keys rather than the capi_public_key struct (now renamed from its original name of ::public_key) from the eosiolib C API. Note that existing contract code that just referred to the type public_key without namespace qualification may have accidentally been using the capi_public_key struct and therefore should ideally be modified to use the eosio::public_key C++ type.
• The account and permission arguments of eosio::check_transaction_authorization are both eosio::name now instead of uint64_t.

eosiolib/ignore.hpp

• Added new type ignore:
  • This type acts as a placeholder for actions that don't want to deserialize their fields but want the types to be reflected in the ABI.

    ACTION action(ignore<some_type>) { some_type st; _ds >> st; }

• Added new type ignore_wrapper:
  • This allows for calling SEND_INLINE_ACTION with ignore_wrapper(some_value) against an action with an ignore of matching types.

Macros

• Added ACTION macro which is simply a shortcut for [[eosio::action]] void.
• Added TABLE macro which is simply a shortcut for struct [[eosio::table]].
• Added CONTRACT macro which is simply a shortcut for class [[eosio::contract]].

CMake

• Added eosio.cdt-config.cmake to allow for find_package(eosio.cdt). See eosio.cdt/examples/hello or eosio.cdt/examples/template for an example.
• Added new macro add_contract. This new contract takes a contract name, cmake target, then any normal arguments you would give to add_executable. See eosio.cdt/examples/hello or eosio.cdt/examples/template.
• New version checking mechanism is included. See eosio.contracts/CMakeLists.txt to see this in use.

libc

• Replaced printf, sprintf, and snprintf with new minimal variants. This allows contracts to use these functions without causing stack overflow issues.

libcxx

• Removed sstream with the intent to return this after more has been done.
• Added __cxa_pure_virtual to allow for pure virtual methods in contract classes.
• std::to_string now works without the issues of stack overflows.

attributes

• Added [[eosio::ignore]] attribute to flag a type as being ignored by the deserializer. This attribute is primarily only used for internal use within eosiolib.
• Added [[eosio::contract]] attribute. This new attribute is used to mark a contract class as "contract" with the name being either the C++ name of the class or a user specified name (i.e. [[eosio::contract("somecontract")]]). This attribute can also be used in conjunction with the eosio::action and eosio::table attributes for tables that you would like to define outside of the eosio::contract class. This is used in conjunction with either the raw eosio-cpp option --contract <name>, -o <name>.wasm or with CMake add_contract. It acts as a filter enabling contract developers to include a header file with attributes from another contract (e.g. eosio.token) while generating an ABI devoid of those actions and tables.

  #include <eosiolib/eosio.hpp>
  using namespace eosio;
  CONTRACT test : public eosio::contract {
  public:
     using contract::contract;
     ACTION acta(){}
     TABLE taba {
        uint64_t a;
        float b;
        uint64_t primary_key() const { return a; }
     };
  };
  struct [[eosio::table, eosio::contract("test")]]
  tabb {
     uint64_t a;
     int b;
  };
  typedef eosio::multi_index<"testtaba"_n, test::taba> table_a;
  typedef eosio::multi_index<"testtabb"_n, tabb> table_b;
  EOSIO_DISPATCH( test, (acta) )

  The above code will produce the tables testtaba and testtabb in your ABI. Example: eosio-cpp -abigen test.cpp -o test.wasm will mark this compilation and ABI generation for the eosio::contract test. The same thing can be done with eosio-cpp -abigen test.cpp -o test_contract.wasm --contract test or with the CMake command add_contract( test, test_contract, test.cpp ). Either of the previous two approaches will produce a test_contract.wasm and test_contract.abi generated under the context of the contract name of test.

Boost

• Boost is now part of the library. No more external dependence on Boost and all system inclusion are within it's sysroot. (Boost will be removed in a future release.)

References

• https://github.com/EOSIO/eosio.cdt/blob/master/README.md