EOS學(xué)習(xí)實(shí)戰(zhàn)(三)教你如何發(fā)幣！

學(xué)習(xí)區(qū)塊鏈乐纸，最刺激的莫過于發(fā)幣衬廷，第一篇文章里介紹了如何搭建EOS開發(fā)環(huán)境，第二篇文章我們已經(jīng)介紹了如何部署調(diào)用合約锯仪，實(shí)際上隱含著對(duì)錢包和賬號(hào)的操作泵督！

這一篇我們重點(diǎn)介紹智能合約如何發(fā)幣！既如何用(yekai)給(dinglinlin)發(fā)幣庶喜。提示：本篇篇幅較長請(qǐng)耐新閱讀小腊。

另，為方便大家交流久窟，需要EOS實(shí)戰(zhàn)系列代碼的小伙伴可以加QQ2082049536索要秩冈，希望跟大家一同進(jìn)步。

使用eosio.token發(fā)幣

我們先將eos官方給提供的eosio.token代碼拷貝到開發(fā)目錄斥扛。

yekaideMacBook-Pro:contracts yk$ cp -r ~/eoshome/eos/contracts/eosio.token/ eosio.token

yekaideMacBook-Pro:contracts yk$ ls

bak? ? ? ? ? ? ? ? eosio.token? ? ?

database? ? ? ? ? jing? ? ? ? ? ? ? tic_tac_toe

debug? ? ? ? ? ? ? moment?

yekaideMacBook-Pro:contracts yk$ cd eosio.token/

yekaideMacBook-Pro:eosio.token yk$ ls

CMakeLists.txt? eosio.token.abi eosio.token.cpp eosio.token.hpp

同樣得到abi文件入问，hpp文件，cpp文件稀颁，缺少wast文件芬失，通過eosiocpp可以生成！

yekaideMacBook-Pro:eosio.token yk$ eosiocpp -o eosio.token.wast eosio.token.cpp eosio.token.cpp:6:10: fatal error: 'eosio.token/eosio.token.hpp' file not found#include ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~

1 error generated.

上述有一個(gè)錯(cuò)誤匾灶，我們需要修改cpp包含頭文件的路徑棱烂，在本目錄下編譯路徑有點(diǎn)問題。修改為 "eosio.token.hpp"阶女。

/**

*? @file

*? @copyright defined in eos/LICENSE.txt

*/

#include "eosio.token.hpp"

namespace eosio {

void token::create( account_name issuer,

? ? ? ? ? ? ? ? ? ? asset? ? ? ? maximum_supply,

? ? ? ? ? ? ? ? ? ? uint8_t? ? ? issuer_can_freeze,

? ? ? ? ? ? ? ? ? ? uint8_t? ? ? issuer_can_recall,

? ? ? ? ? ? ? ? ? ? uint8_t? ? ? issuer_can_whitelist )

{

? ? require_auth( _self );

? ? auto sym = maximum_supply.symbol;

? ? eosio_assert( sym.is_valid(), "invalid symbol name" );

? ? eosio_assert( maximum_supply.is_valid(), "invalid supply");

? ? eosio_assert( maximum_supply.amount > 0, "max-supply must be positive");

? ? stats statstable( _self, sym.name() );

? ? auto existing = statstable.find( sym.name() );

? ? eosio_assert( existing == statstable.end(), "token with symbol already exists" );

? ? statstable.emplace( _self, [&]( auto& s ) {

? ? ? s.supply.symbol = maximum_supply.symbol;

? ? ? s.max_supply? ? = maximum_supply;

? ? ? s.issuer? ? ? ? = issuer;

? ? ? s.can_freeze? ? = issuer_can_freeze;

? ? ? s.can_recall? ? = issuer_can_recall;

? ? ? s.can_whitelist = issuer_can_whitelist;

? ? });

}

void token::issue( account_name to, asset quantity, string memo )

{

? ? print( "issue" );

? ? auto sym = quantity.symbol.name();

? ? stats statstable( _self, sym );

? ? const auto& st = statstable.get( sym );

? ? require_auth( st.issuer );

? ? eosio_assert( quantity.is_valid(), "invalid quantity" );

? ? eosio_assert( quantity.amount > 0, "must issue positive quantity" );

? ? eosio_assert( quantity <= st.max_supply - st.supply, "quantity exceeds available supply");

? ? statstable.modify( st, 0, [&]( auto& s ) {

? ? ? s.supply += quantity;

? ? });

? ? add_balance( st.issuer, quantity, st, st.issuer );

? ? if( to != st.issuer )

? ? {

? ? ? SEND_INLINE_ACTION( *this, transfer, {st.issuer,N(active)}, {st.issuer, to, quantity, memo} );

? ? }

}

void token::transfer( account_name from,

? ? ? ? ? ? ? ? ? ? ? account_name to,

? ? ? ? ? ? ? ? ? ? ? asset? ? ? ? quantity,

? ? ? ? ? ? ? ? ? ? ? string? ? ? /*memo*/ )

{

? ? print( "transfer" );

? ? require_auth( from );

? ? auto sym = quantity.symbol.name();

? ? stats statstable( _self, sym );

? ? const auto& st = statstable.get( sym );

? ? require_recipient( from );

? ? require_recipient( to );

? ? eosio_assert( quantity.is_valid(), "invalid quantity" );

? ? eosio_assert( quantity.amount > 0, "must transfer positive quantity" );

? ? sub_balance( from, quantity, st );

? ? add_balance( to, quantity, st, from );

}

void token::sub_balance( account_name owner, asset value, const currency_stats& st ) {

? accounts from_acnts( _self, owner );

? const auto& from = from_acnts.get( value.symbol.name() );

? eosio_assert( from.balance.amount >= value.amount, "overdrawn balance" );

? if( has_auth( owner ) ) {

? ? ? eosio_assert( !st.can_freeze || !from.frozen, "account is frozen by issuer" );

? ? ? eosio_assert( !st.can_freeze || !st.is_frozen, "all transfers are frozen by issuer" );

? ? ? eosio_assert( !st.enforce_whitelist || from.whitelist, "account is not white listed" );

? } else if( has_auth( st.issuer ) ) {

? ? ? eosio_assert( st.can_recall, "issuer may not recall token" );

? } else {

? ? ? eosio_assert( false, "insufficient authority" );

? }

? from_acnts.modify( from, owner, [&]( auto& a ) {

? ? ? a.balance -= value;

? });

}

void token::add_balance( account_name owner, asset value, const currency_stats& st, account_name ram_payer )

{

? accounts to_acnts( _self, owner );

? auto to = to_acnts.find( value.symbol.name() );

? if( to == to_acnts.end() ) {

? ? ? eosio_assert( !st.enforce_whitelist, "can only transfer to white listed accounts" );

? ? ? to_acnts.emplace( ram_payer, [&]( auto& a ){

? ? ? ? a.balance = value;

? ? ? });

? } else {

? ? ? eosio_assert( !st.enforce_whitelist || to->whitelist, "receiver requires whitelist by issuer" );

? ? ? to_acnts.modify( to, 0, [&]( auto& a ) {

? ? ? ? a.balance += value;

? ? ? });

? }

}

} /// namespace eosio

EOSIO_ABI( eosio::token, (create)(issue)(transfer) )

yekaideMacBook-Pro:eosio.token yk$

再次執(zhí)行編譯生成wast文件

yekaideMacBook-Pro:eosio.token yk$ eosiocpp -o eosio.token.wast eosio.token.cpp

終于可以發(fā)幣了

有可能看到如圖所示颊糜，這是由于nodes重啟后哩治，錢包需要解鎖，此時(shí)上篇提到的錢包密碼在此處就將有用武之地了衬鱼！

yekaideMacBook-Pro:eosio.token yk$ cleos wallet unlock

輸入錢包密碼就會(huì)解鎖成功了业筏！再次發(fā)布合約！

yekaideMacBook-Pro:eosio.token yk$ cleos set contract yekai ../eosio.token/

Reading WAST/WASM from ../eosio.token/eosio.token.wast...

Assembling WASM...

Publishing contract...

executed transaction: 0cfdf14e4d5d7351b31ba88a029b9c96693fdaf9d9f7738738356cb01ad48dff? 8320 bytes? 2200576 cycles

#? ? ? ? eosio <= eosio::setcode? ? ? ? ? ? ? {"account":"yekai","vmtype":0,"vmversion":0,"code":"0061736d010000000181011560067f7e7f7f7f7f0060057f...

#? ? ? ? eosio <= eosio::setabi? ? ? ? ? ? ? ? {"account":"yekai","abi":{"types":[],"structs":[{"name":"transfer","base":"","fields":[{"name":"from...

看到上述結(jié)果代表成了鸟赫！激動(dòng)人心的時(shí)刻也開始了蒜胖！

馬上發(fā)幣，手里有幣惯疙，心里不慌

計(jì)劃發(fā)布一個(gè)葉開幣翠勉，持幣的可以找我換飛刀！需要指定發(fā)行者issuer霉颠，指定最大發(fā)行量以及幣符號(hào)（YKC）对碌，還有三個(gè)參數(shù)can_freeze，can_recall蒿偎，can_whitelist分別代表是否可以凍結(jié)朽们，是否可以回收，是否使用白名單诉位。

yekaideMacBook-Pro:eosio.token yk$ cleos push action yekai create '{"issuer":"yekai", "maximum_supply": "1000000000.0000 YKC", "can_freeze": 1, "can_recall": 1, "can_whitelist": 1}' -p yekai@active

executed transaction: 60aba3068a0e3afebd81d23c3a5b954321eb1d29926a46199c7168590f3cf1fa? 248 bytes? 104448 cycles

#? ? ? ? yekai <= yekai::create? ? ? ? ? ? ? ? {"issuer":"yekai","maximum_supply":"1000000000.0000 YKC","can_freeze":1,"can_recall":1,"can_whitelis...

這樣執(zhí)行成功骑脱，我們就可以發(fā)幣了

yekaideMacBook-Pro:eosio.token yk$ cleos push action yekai issue '{"to":"yekai","quantity":"1000.0000 YKC","memo":"issue first"}' -p yekai@active

executed transaction: fd0079f68e354e70a2c6af53d091531064681a256fbe807292bb11b20dcc408d? 264 bytes? 109568 cycles

#? ? ? ? yekai <= yekai::issue? ? ? ? ? ? ? ? {"to":"yekai","quantity":"1000.0000 YKC","memo":"issue first"}

>> issue

可以查看yekai當(dāng)前的余額，兩個(gè)yekai一個(gè)代表合約苍糠，一個(gè)代表范圍叁丧，accounts代表表名，accounts在哪定義的岳瞭？

yekaideMacBook-Pro:eosio.token yk$ cleos get table yekai yekai accounts

{

? "rows": [{

? ? ? "balance": "1000.0000 YKC",

? ? ? "frozen": 0,

? ? ? "whitelist": 1

? ? }

? ],

? "more": false

}

轉(zhuǎn)賬給dinglinlin拥娄，先創(chuàng)建一個(gè)賬戶dinglinlin

yekaideMacBook-Pro:eosio.token yk$ cleos create key

Private key: 5JibbdFPc4f5ZX9Qq8sWpX8yACNwAzex5ogHWxtTGVSYeUkvWJq

Public key: EOS5vn5Jj5oU1zP7rKDwbXsEjLbQnT8yvLF1PcyCEFKzoAX3xVz2J

yekaideMacBook-Pro:eosio.token yk$ cleos create account eosio dinglinlin EOS5vn5Jj5oU1zP7rKDwbXsEjLbQnT8yvLF1PcyCEFKzoAX3xVz2J EOS5vn5Jj5oU1zP7rKDwbXsEjLbQnT8yvLF1PcyCEFKzoAX3xVz2J

executed transaction: d710f137d34568981eb0bd65fbf4e7306cc813e47b067d06138af9eea15b352a? 352 bytes? 102400 cycles

#? ? ? ? eosio <= eosio::newaccount? ? ? ? ? ? {"creator":"eosio","name":"dinglinlin","owner":{"threshold":1,"keys":[{"key":"EOS5vn5Jj5oU1zP7rKDwbX...

yekaideMacBook-Pro:eosio.token yk$

yekaideMacBook-Pro:eosio.token yk$ cleos wallet import 5JibbdFPc4f5ZX9Qq8sWpX8yACNwAzex5ogHWxtTGVSYeUkvWJq

imported private key for: EOS5vn5Jj5oU1zP7rKDwbXsEjLbQnT8yvLF1PcyCEFKzoAX3xVz2J

轉(zhuǎn)賬給dinglinlin

yekaideMacBook-Pro:eosio.token yk$ cleos push action yekai transfer '{"from":"yekai","to":"dinglinlin","quantity":"20.0000 YKC","memo":"my first transfer"}' -p yekai@active

executed transaction: ae530eaab3c7b2dbecb73df0dc7d74c5861ff1d0cc50655f2f31d46004e4187d? 272 bytes? 112640 cycles

#? ? ? ? yekai <= yekai::transfer? ? ? ? ? ? ? {"from":"yekai","to":"dinglinlin","quantity":"20.0000 YKC","memo":"my first transfer"}

>> transfer

#? ? dinglinlin <= yekai::transfer? ? ? ? ? ? ? {"from":"yekai","to":"dinglinlin","quantity":"20.0000 YKC","memo":"my first transfer"}

再次查看余額，葉開和丁琳琳金額發(fā)生了變化瞳筏！

yekaideMacBook-Pro:eosio.token yk$ cleos get table yekai dinglinlin accounts

{

? "rows": [{

? ? ? "balance": "20.0000 YKC",

? ? ? "frozen": 0,

? ? ? "whitelist": 1

? ? }

? ],

? "more": false

}

yekaideMacBook-Pro:eosio.token yk$ cleos get table yekai yekai accounts

{

? "rows": [{

? ? ? "balance": "980.0000 YKC",

? ? ? "frozen": 0,

? ? ? "whitelist": 1

? ? }

? ],

? "more": false

}

abi文件三要素

發(fā)幣已然成功稚瘾，然而少了點(diǎn)什么，我們?cè)倩剡^來介紹abi文件的內(nèi)容姚炕。abi文件有三要素摊欠，當(dāng)然不是陽光、空氣和水柱宦！abi文件的三要素是struct些椒，action，table掸刊。

yekaideMacBook-Pro:eosio.token yk$ cat eosio.token.abi

{

? "types": [],

? "structs": [{

? ? ? "name": "transfer",

? ? ? "base": "",

? ? ? "fields": [

? ? ? ? {"name":"from", "type":"account_name"},

? ? ? ? {"name":"to", "type":"account_name"},

? ? ? ? {"name":"quantity", "type":"asset"},

? ? ? ? {"name":"memo", "type":"string"}

? ? ? ]

? ? },{

? ? "name": "create",

? ? "base": "",

? ? "fields": [

? ? ? ? {"name":"issuer", "type":"account_name"},

? ? ? ? {"name":"maximum_supply", "type":"asset"},

? ? ? ? {"name":"can_freeze", "type":"uint8"},

? ? ? ? {"name":"can_recall", "type":"uint8"},

? ? ? ? {"name":"can_whitelist", "type":"uint8"}

? ? ]

? },{

? ? "name": "issue",

? ? "base": "",

? ? "fields": [

? ? ? ? {"name":"to", "type":"account_name"},

? ? ? ? {"name":"quantity", "type":"asset"},

? ? ? ? {"name":"memo", "type":"string"}

? ? ]

? },{

? ? ? "name": "account",

? ? ? "base": "",

? ? ? "fields": [

? ? ? ? {"name":"balance", "type":"asset"},

? ? ? ? {"name":"frozen", "type":"uint8"},

? ? ? ? {"name":"whitelist", "type":"uint8"}

? ? ? ]

? ? },{

? ? ? "name": "currency_stats",

? ? ? "base": "",

? ? ? "fields": [

? ? ? ? {"name":"supply", "type":"asset"},

? ? ? ? {"name":"max_supply", "type":"asset"},

? ? ? ? {"name":"issuer", "type":"account_name"},

? ? ? ? {"name":"can_freeze", "type":"uint8"},

? ? ? ? {"name":"can_recall", "type":"uint8"},

? ? ? ? {"name":"can_whitelist", "type":"uint8"},

? ? ? ? {"name":"is_frozen", "type":"uint8"},

? ? ? ? {"name":"enforce_whitelist", "type":"uint8"}

? ? ? ]

? ? }

? ],

? "actions": [{

? ? ? "name": "transfer",

? ? ? "type": "transfer",

? ? ? "ricardian_contract": ""

? ? },{

? ? ? "name": "issue",

? ? ? "type": "issue",

? ? ? "ricardian_contract": ""

? ? }, {

? ? ? "name": "create",

? ? ? "type": "create",

? ? ? "ricardian_contract": ""

? ? }

? ],

? "tables": [{

? ? ? "name": "accounts",

? ? ? "type": "account",

? ? ? "index_type": "i64",

? ? ? "key_names" : ["currency"],

? ? ? "key_types" : ["uint64"]

? ? },{

? ? ? "name": "stat",

? ? ? "type": "currency_stats",

? ? ? "index_type": "i64",

? ? ? "key_names" : ["currency"],

? ? ? "key_types" : ["uint64"]

? ? }

? ],

? "ricardian_clauses": []

}

struct 結(jié)構(gòu)

struct不會(huì)碰到太多問題免糕，就是我們定義的結(jié)構(gòu)體

action 動(dòng)作

action是abi文件的靈魂，eos是以action驅(qū)動(dòng)，當(dāng)然锝得得action说墨。

table

table其實(shí)是非必須的，比如hello的例子中就沒有table苍柏，table做什么用呢尼斧？既然是table，就可以當(dāng)成數(shù)據(jù)庫的table试吁，那么什么用處也就清晰了棺棵！本例使用table存儲(chǔ)每個(gè)用戶的持幣余額！說到這里熄捍，也就能理解之前的操作為什么用accounts這個(gè)表了烛恤！

修改示例代碼重新得到abi

很遺憾的是官方給的示例代碼是無法通過eosiocpp生成官方版的abi文件的，咱們做一下跳坑練習(xí)余耽！

yekaideMacBook-Pro:eosio.token yk$ eosiocpp -g eosio.token.abi eosio.token.cpp

yekaideMacBook-Pro:eosio.token yk$ cat eosio.token.abi

{

? "____comment": "This file was generated by eosio-abigen. DO NOT EDIT - 2018-05-11T06:32:03",

? "types": [],

? "structs": [],

? "actions": [],

? "tables": [],

? "ricardian_clauses": []

}

很郁悶的發(fā)現(xiàn)abi的文件空空如也缚柏，整個(gè)人都不好了！接下來就看動(dòng)手能力了碟贾，我們先將hpp和cpp源碼改造一下币喧，將namespace的使用方式去掉，經(jīng)過證明袱耽，我們需要使用全局空間杀餐，不能再次定義eosio這個(gè)命名空間！

代碼改造如下（第一次修改）

eosio.token.hpp

/**

* @file

* @copyright defined in eos/LICENSE.txt

*/

#pragma once

#include#include#includenamespace eosiosystem { class system_contract;}using namespace eosio ; using std::string; class token : public contract { public: token( account_name self ):contract(self){} /// @abi action void create( account_name issuer, asset maximum_supply, uint8_t issuer_can_freeze, uint8_t issuer_can_recall, uint8_t issuer_can_whitelist ); void issue( account_name to, asset quantity, string memo ); void transfer( account_name from, account_name to, asset quantity, string memo ); private: friend eosiosystem::system_contract; inline asset get_supply( symbol_name sym )const; inline asset get_balance( account_name owner, symbol_name sym )const; private: struct account { asset balance; bool frozen = false; bool whitelist = true; uint64_t primary_key()const { return balance.symbol.name(); } }; struct currency_stats { asset supply; asset max_supply; account_name issuer; bool can_freeze = true; bool can_recall = true; bool can_whitelist = true; bool is_frozen = false; bool enforce_whitelist = false; uint64_t primary_key()const { return supply.symbol.name(); } }; typedef eosio::multi_indexaccounts; typedef eosio::multi_index stats;

? ? ? ? void sub_balance( account_name owner, asset value, const currency_stats& st );

? ? ? ? void add_balance( account_name owner, asset value, const currency_stats& st,

? ? ? ? ? ? ? ? ? ? ? ? ? account_name ram_payer );

? ? ? public:

? ? ? ? struct transfer_args {

? ? ? ? ? ? account_name? from;

? ? ? ? ? ? account_name? to;

? ? ? ? ? ? asset? ? ? ? quantity;

? ? ? ? ? ? string? ? ? ? memo;

? ? ? ? };

? };

? asset token::get_supply( symbol_name sym )const

? {

? ? ? stats statstable( _self, sym );

? ? ? const auto& st = statstable.get( sym );

? ? ? return st.supply;

? }

? asset token::get_balance( account_name owner, symbol_name sym )const

? {

? ? ? accounts accountstable( _self, owner );

? ? ? const auto& ac = accountstable.get( sym );

? ? ? return ac.balance;

? }

eosio.token.cpp

/**

*? @file

*? @copyright defined in eos/LICENSE.txt

*/

#include "eosio.token.hpp"

void token::create( account_name issuer,

? ? ? ? ? ? ? ? ? ? asset? ? ? ? maximum_supply,

? ? ? ? ? ? ? ? ? ? uint8_t? ? ? issuer_can_freeze,

? ? ? ? ? ? ? ? ? ? uint8_t? ? ? issuer_can_recall,

? ? ? ? ? ? ? ? ? ? uint8_t? ? ? issuer_can_whitelist )

{

? ? require_auth( _self );

? ? auto sym = maximum_supply.symbol;

? ? eosio_assert( sym.is_valid(), "invalid symbol name" );

? ? eosio_assert( maximum_supply.is_valid(), "invalid supply");

? ? eosio_assert( maximum_supply.amount > 0, "max-supply must be positive");

? ? stats statstable( _self, sym.name() );

? ? auto existing = statstable.find( sym.name() );

? ? eosio_assert( existing == statstable.end(), "token with symbol already exists" );

? ? statstable.emplace( _self, [&]( auto& s ) {

? ? ? s.supply.symbol = maximum_supply.symbol;

? ? ? s.max_supply? ? = maximum_supply;

? ? ? s.issuer? ? ? ? = issuer;

? ? ? s.can_freeze? ? = issuer_can_freeze;

? ? ? s.can_recall? ? = issuer_can_recall;

? ? ? s.can_whitelist = issuer_can_whitelist;

? ? });

}

void token::issue( account_name to, asset quantity, string memo )

{

? ? print( "issue" );

? ? auto sym = quantity.symbol.name();

? ? stats statstable( _self, sym );

? ? const auto& st = statstable.get( sym );

? ? require_auth( st.issuer );

? ? eosio_assert( quantity.is_valid(), "invalid quantity" );

? ? eosio_assert( quantity.amount > 0, "must issue positive quantity" );

? ? eosio_assert( quantity <= st.max_supply - st.supply, "quantity exceeds available supply");

? ? statstable.modify( st, 0, [&]( auto& s ) {

? ? ? s.supply += quantity;

? ? });

? ? add_balance( st.issuer, quantity, st, st.issuer );

? ? if( to != st.issuer )

? ? {

? ? ? SEND_INLINE_ACTION( *this, transfer, {st.issuer,N(active)}, {st.issuer, to, quantity, memo} );

? ? }

}

void token::transfer( account_name from,

? ? ? ? ? ? ? ? ? ? ? account_name to,

? ? ? ? ? ? ? ? ? ? ? asset? ? ? ? quantity,

? ? ? ? ? ? ? ? ? ? ? string? ? ? /*memo*/ )

{

? ? print( "transfer" );

? ? require_auth( from );

? ? auto sym = quantity.symbol.name();

? ? stats statstable( _self, sym );

? ? const auto& st = statstable.get( sym );

? ? require_recipient( from );

? ? require_recipient( to );

? ? eosio_assert( quantity.is_valid(), "invalid quantity" );

? ? eosio_assert( quantity.amount > 0, "must transfer positive quantity" );

? ? sub_balance( from, quantity, st );

? ? add_balance( to, quantity, st, from );

}

void token::sub_balance( account_name owner, asset value, const currency_stats& st ) {

? accounts from_acnts( _self, owner );

? const auto& from = from_acnts.get( value.symbol.name() );

? eosio_assert( from.balance.amount >= value.amount, "overdrawn balance" );

? if( has_auth( owner ) ) {

? ? ? eosio_assert( !st.can_freeze || !from.frozen, "account is frozen by issuer" );

? ? ? eosio_assert( !st.can_freeze || !st.is_frozen, "all transfers are frozen by issuer" );

? ? ? eosio_assert( !st.enforce_whitelist || from.whitelist, "account is not white listed" );

? } else if( has_auth( st.issuer ) ) {

? ? ? eosio_assert( st.can_recall, "issuer may not recall token" );

? } else {

? ? ? eosio_assert( false, "insufficient authority" );

? }

? from_acnts.modify( from, owner, [&]( auto& a ) {

? ? ? a.balance -= value;

? });

}

void token::add_balance( account_name owner, asset value, const currency_stats& st, account_name ram_payer )

{

? accounts to_acnts( _self, owner );

? auto to = to_acnts.find( value.symbol.name() );

? if( to == to_acnts.end() ) {

? ? ? eosio_assert( !st.enforce_whitelist, "can only transfer to white listed accounts" );

? ? ? to_acnts.emplace( ram_payer, [&]( auto& a ){

? ? ? ? a.balance = value;

? ? ? });

? } else {

? ? ? eosio_assert( !st.enforce_whitelist || to->whitelist, "receiver requires whitelist by issuer" );

? ? ? to_acnts.modify( to, 0, [&]( auto& a ) {

? ? ? ? a.balance += value;

? ? ? });

? }

}

EOSIO_ABI( token, (create)(issue)(transfer) )

這次abi文件有變化了朱巨，但是好像還缺少點(diǎn)什么!

{

? "____comment": "This file was generated by eosio-abigen. DO NOT EDIT - 2018-05-11T06:41:35",

? "types": [],

? "structs": [{

? ? ? "name": "create",

? ? ? "base": "",

? ? ? "fields": [{

? ? ? ? ? "name": "issuer",

? ? ? ? ? "type": "account_name"

? ? ? ? },{

? ? ? ? ? "name": "maximum_supply",

? ? ? ? ? "type": "asset"

? ? ? ? },{

? ? ? ? ? "name": "issuer_can_freeze",

? ? ? ? ? "type": "uint8"

? ? ? ? },{

? ? ? ? ? "name": "issuer_can_recall",

? ? ? ? ? "type": "uint8"

? ? ? ? },{

? ? ? ? ? "name": "issuer_can_whitelist",

? ? ? ? ? "type": "uint8"

? ? ? ? }

? ? ? ]

? ? },{

? ? ? "name": "issue",

? ? ? "base": "",

? ? ? "fields": [{

? ? ? ? ? "name": "to",

? ? ? ? ? "type": "account_name"

? ? ? ? },{

? ? ? ? ? "name": "quantity",

? ? ? ? ? "type": "asset"

? ? ? ? },{

? ? ? ? ? "name": "memo",

? ? ? ? ? "type": "string"

? ? ? ? }

? ? ? ]

? ? },{

? ? ? "name": "transfer",

? ? ? "base": "",

? ? ? "fields": [{

? ? ? ? ? "name": "from",

? ? ? ? ? "type": "account_name"

? ? ? ? },{

? ? ? ? ? "name": "to",

? ? ? ? ? "type": "account_name"

? ? ? ? },{

? ? ? ? ? "name": "quantity",

? ? ? ? ? "type": "asset"

? ? ? ? },{

? ? ? ? ? "name": "memo",

? ? ? ? ? "type": "string"

? ? ? ? }

? ? ? ]

? ? }

? ],

? "actions": [{

? ? ? "name": "create",

? ? ? "type": "create",

? ? ? "ricardian_contract": ""

? ? },{

? ? ? "name": "issue",

? ? ? "type": "issue",

? ? ? "ricardian_contract": ""

? ? },{

? ? ? "name": "transfer",

? ? ? "type": "transfer",

? ? ? "ricardian_contract": ""

? ? }

? ],

? "tables": [],

? "ricardian_clauses": []

}

上面看似abi文件沒有問題了史翘，但實(shí)際上tables部分，也就是abi的三要素少了一個(gè)tables冀续，這樣數(shù)據(jù)是存儲(chǔ)不下來的琼讽，發(fā)幣會(huì)有問題！

關(guān)鍵點(diǎn)沥阳，添加注釋

再次編譯跨琳，結(jié)果更多的錯(cuò)誤！不要慌桐罕！

abi_generation_exception: Unable to generate abi

false: types can only be: vector, struct, class or a built-in type. (bool)

? ? {"type":"bool"}

? ? thread-0? abi_generator.cpp:606 add_type

? ? {}

? ? thread-0? abi_generator.cpp:290 handle_decl

在eos的智能合約里脉让，導(dǎo)出的table數(shù)據(jù)中不可以有bool類型，其實(shí)提示的已經(jīng)較為明顯了功炮，另外就是加那行注釋是有實(shí)際作用的溅潜，eosiocpp會(huì)做正則匹配，然后才會(huì)導(dǎo)出table信息到abi薪伏。

/**

*? @file

*? @copyright defined in eos/LICENSE.txt

*/

#pragma once

#include

#include

#include

namespace eosiosystem {

? class system_contract;

}

using namespace eosio ;

? using std::string;

? class token : public contract {

? ? ? public:

? ? ? ? token( account_name self ):contract(self){}

? ? ? ? /// @abi action

? ? ? ? void create( account_name issuer,

? ? ? ? ? ? ? ? ? ? ? asset? ? ? ? maximum_supply,

? ? ? ? ? ? ? ? ? ? ? uint8_t? ? ? issuer_can_freeze,

? ? ? ? ? ? ? ? ? ? ? uint8_t? ? ? issuer_can_recall,

? ? ? ? ? ? ? ? ? ? ? uint8_t? ? ? issuer_can_whitelist );

? ? ? ? void issue( account_name to, asset quantity, string memo );

? ? ? ? void transfer( account_name from,

? ? ? ? ? ? ? ? ? ? ? ? account_name to,

? ? ? ? ? ? ? ? ? ? ? ? asset? ? ? ? quantity,

? ? ? ? ? ? ? ? ? ? ? ? string? ? ? memo );

? ? ? private:

? ? ? ? friend eosiosystem::system_contract;

? ? ? ? inline asset get_supply( symbol_name sym )const;

? ? ? ? inline asset get_balance( account_name owner, symbol_name sym )const;

? ? ? private:

? ? ? ? /// @abi table accounts i64

? ? ? ? struct account {

? ? ? ? ? ? asset? ? balance;

? ? ? ? ? ? uint8_t frozen? ? = 0;

? ? ? ? ? ? uint8_t? ? whitelist = 1;

? ? ? ? ? ? uint64_t primary_key()const { return balance.symbol.name(); }

? ? ? ? };

? ? ? ? /// @abi table stats i64

? ? ? ? struct stat {

? ? ? ? ? ? asset? ? ? ? ? supply;

? ? ? ? ? ? asset? ? ? ? ? max_supply;

? ? ? ? ? ? account_name? issuer;

? ? ? ? ? ? uint8_t? ? ? ? ? can_freeze? ? ? ? = 1;

? ? ? ? ? ? uint8_t? ? ? ? ? can_recall? ? ? ? = 1;

? ? ? ? ? ? uint8_t? ? ? ? ? can_whitelist? ? ? = 1;

? ? ? ? ? ? uint8_t? ? ? ? ? is_frozen? ? ? ? ? = 0;

? ? ? ? ? ? uint8_t? ? ? ? ? enforce_whitelist? = 0;

? ? ? ? ? ? uint64_t primary_key()const { return supply.symbol.name(); }

? ? ? ? };

? ? ? ? typedef eosio::multi_index accounts;

? ? ? ? typedef eosio::multi_index stats;

? ? ? ? void sub_balance( account_name owner, asset value, const stat& st );

? ? ? ? void add_balance( account_name owner, asset value, const stat& st,

? ? ? ? ? ? ? ? ? ? ? ? ? account_name ram_payer );

? ? ? public:

? ? ? ? struct transfer_args {

? ? ? ? ? ? account_name? from;

? ? ? ? ? ? account_name? to;

? ? ? ? ? ? asset? ? ? ? quantity;

? ? ? ? ? ? string? ? ? ? memo;

? ? ? ? };

? };

? asset token::get_supply( symbol_name sym )const

? {

? ? ? stats statstable( _self, sym );

? ? ? const auto& st = statstable.get( sym );

? ? ? return st.supply;

? }

? asset token::get_balance( account_name owner, symbol_name sym )const

? {

? ? ? accounts accountstable( _self, owner );

? ? ? const auto& ac = accountstable.get( sym );

? ? ? return ac.balance;

? }

注意一下修改變化滚澜，account和stat結(jié)構(gòu)體前都加了注釋，另外導(dǎo)出時(shí)對(duì)table的name長度有限制嫁怀，所以去掉了currency_和后面的s设捐，當(dāng)然相應(yīng)的函數(shù)調(diào)用部分都要調(diào)整借浊。別忘了同步修改cpp文件對(duì)應(yīng)的函數(shù)接口部分，這樣基本可以大公告成了萝招！

再次發(fā)幣

先部署合約

cleos set contract yekai ../eosio.token

給linlin妹子再來點(diǎn)幣

yk$ cleos push action yekai transfer '{"from":"yekai","to":"dinglinlin","quantity":"66.0000 YKC","memo":"my sencond transfer"}' -p yekai@active

executed transaction: 08f6f04ee43e51423e84379080e1788461fc6b36bdbbf58c3a1fe518e2140e90? 280 bytes? 112640 cycles

#? ? ? ? yekai <= yekai::transfer? ? ? ? ? ? ? {"from":"yekai","to":"dinglinlin","quantity":"66.0000 YKC","memo":"my sencond transfer"}

>> transfer

#? ? dinglinlin <= yekai::transfer? ? ? ? ? ? ? {"from":"yekai","to":"dinglinlin","quantity":"66.0000 YKC","memo":"my sencond transfer"}

再次分別查看余額

yekaideMacBook-Pro:eosio.token yk$ cleos get table yekai yekai accounts

{

? "rows": [{

? ? ? "balance": "914.0000 YKC",

? ? ? "frozen": 0,

? ? ? "whitelist": 1

? ? }

? ],

? "more": false

}

yekaideMacBook-Pro:eosio.token yk$ cleos get table yekai dinglinlin accounts

{

? "rows": [{

? ? ? "balance": "86.0000 YKC",

? ? ? "frozen": 0,

? ? ? "whitelist": 1

? ? }

? ],

? "more": false

}

總結(jié)

本篇主要介紹如何發(fā)幣蚂斤，如何編譯智能合約代碼，以及智能合約編寫時(shí)碰到的問題槐沼，把遇到的坑總結(jié)如下：

/// @abi 有特殊作用

類型必須使用內(nèi)建類型曙蒸，或者結(jié)構(gòu)體，類岗钩，vector等

table結(jié)構(gòu)體長度是有限制的纽窟，不能太長，這也需要注意

table指定主鍵有時(shí)也需要自己指定兼吓，例如：/// @abi table tablename i64

?著作權(quán)歸作者所有,轉(zhuǎn)載或內(nèi)容合作請(qǐng)聯(lián)系作者

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EOS學(xué)習(xí)實(shí)戰(zhàn)(三)教你如何發(fā)幣愿汰！