cli.go

package main

import (
	"flag"
	"fmt"
	"log"
	"os"
	"strconv"
)

// CLI responsible for processing command line arguments
type CLI struct {
	bc *Blockchain
}

// print how to use cli
func (cli *CLI) printUsage() {
	fmt.Println("Usage:")
	fmt.Println("  addblock -data BLOCK_DATA - add a block to the blockchain")
	fmt.Println("  printchain - print all the blocks of the blockchain")
}

// 检查有没有参数
func (cli *CLI) validateArgs() {
	if len(os.Args) < 2 {
		cli.printUsage()
		os.Exit(1)
	}
}

// 添加区块 --在调用了一层
func (cli *CLI) addBlock(data string) {
	cli.bc.AddBlock(data)
	fmt.Println("Success!")
}

func (cli *CLI) printChain() {
	bci := cli.bc.Iterator()
	for {
		block := bci.Next()
		fmt.Printf("Prev. hash: %x\n", block.PrevBlockHash)
		fmt.Printf("Data: %s\n", block.Data)
		fmt.Printf("Hash: %x\n", block.Hash)
		pow := NewProofOfWork(block)
		fmt.Printf("PoW: %s\n", strconv.FormatBool(pow.Validate()))
		fmt.Println()

		if len(block.PrevBlockHash) == 0 {
			break
		}
	}
}

// Run parses command line arguments and processes commands
func (cli *CLI) Run() {
	cli.validateArgs()
	// parse command-line arguments
	// 创建两个子命令addblock, printchain
	addBlockCmd := flag.NewFlagSet("addblock", flag.ExitOnError)
	printChainCmd := flag.NewFlagSet("printchain", flag.ExitOnError)
	// 给add 添加-data标志，在这儿拿到用户传的数据
	addBlockData := addBlockCmd.String("data", "", "Block data")
	// 在这儿拿到的参数， 用户输入什么命令
	switch os.Args[1] {
	case "addblock":
		err := addBlockCmd.Parse(os.Args[2:])
		if err != nil {
			log.Panic(err)
		}
	case "printchain":
		err := printChainCmd.Parse(os.Args[2:])
		if err != nil {
			log.Panic(err)
		}
	default:
		cli.printUsage()
		os.Exit(1)
	}
	// 看看究竟是那个命令
	if addBlockCmd.Parsed() {
		if *addBlockData == "" {
			addBlockCmd.Usage()
			os.Exit(1)
		}
		cli.addBlock(*addBlockData)
	}

	if printChainCmd.Parsed() {
		cli.printChain()
	}
}