欢迎您访问程序员文章站本站旨在为大家提供分享程序员计算机编程知识!
您现在的位置是: 首页

使用golang统计代码行数

程序员文章站 2022-04-18 18:29:39
...

有关golang的介绍请参考我的另一篇博文.

 

 

本文通过递归遍历src目录, 统计代码行数. 涉及到的知识点有:

1. 目录遍历.

2. 读取文件.

3. 使用channel进行goroutine间的通信.

4. 使用sync包进行传统的共享内存方式的同步.

5. 错误处理.

6. defer语句的使用.

 

 

在程序中有详细的注释:

 

// a simple go program for computing total line of souce files stored in one dir
package main

import (
	"fmt"
	"bufio"
	"os"
	"sync"
	"strings"
)

var (
	linesum int
	mutex   *sync.Mutex = new(sync.Mutex)
)

var (
	// the dir where souce file stored
	rootPath string = "/home/xing/Dropbox/source/go/src"
	// exclude these sub dirs
	nodirs [5]string = [...]string{"/bitbucket.org", "/github.com", "/goplayer", "/uniqush", "/code.google.com"}
	// the suffix name you care
	suffixname string = ".go"
)

func main() {
	argsLen := len(os.Args)
	if argsLen == 2 {
		rootPath = os.Args[1]
	} else if argsLen == 3 {
		rootPath = os.Args[1]
		suffixname = os.Args[2]
	}
	// sync chan using for waiting
	done := make(chan bool)
	go codeLineSum(rootPath, done)
	<-done

	fmt.Println("total line:", linesum)
}

// compute souce file line number
func codeLineSum(root string, done chan bool) {
	var goes int              // children goroutines number
	godone := make(chan bool) // sync chan using for waiting all his children goroutines finished
	isDstDir := checkDir(root)
	defer func() {
		if pan := recover(); pan != nil {
			fmt.Printf("root: %s, panic:%#v\n", root, pan)
		}

		// waiting for his children done
		for i := 0; i < goes; i++ {
			<-godone
		}

		// this goroutine done, notify his parent
		done <- true
	}()
	if !isDstDir {
		return
	}

	rootfi, err := os.Lstat(root)
	checkerr(err)

	rootdir, err := os.Open(root)
	checkerr(err)
	defer rootdir.Close()

	if rootfi.IsDir() {
		fis, err := rootdir.Readdir(0)
		checkerr(err)
		for _, fi := range fis {
			if strings.HasPrefix(fi.Name(), ".") {
				continue
			}
			goes++
			if fi.IsDir() {
				go codeLineSum(root+"/"+fi.Name(), godone)
			} else {
				go readfile(root+"/"+fi.Name(), godone)
			}
		}
	} else {
		goes = 1 // if rootfi is a file, current goroutine has only one child
		go readfile(root, godone)
	}
}

func readfile(filename string, done chan bool) {
	var line int
	isDstFile := strings.HasSuffix(filename, suffixname)
	defer func() {
		if pan := recover(); pan != nil {
			fmt.Printf("filename: %s, panic:%#v\n", filename, pan)
		}
		if isDstFile {
			addLineNum(line)
			fmt.Printf("file %s complete, line = %d\n", filename, line)
		}
		// this goroutine done, notify his parent
		done <- true
	}()
	if !isDstFile {
		return
	}

	file, err := os.Open(filename)
	checkerr(err)
	defer file.Close()

	reader := bufio.NewReader(file)
	for {
		_, isPrefix, err := reader.ReadLine()
		if err != nil {
			break
		}
		if !isPrefix {
			line++
		}
	}
}

// check whether this dir is the dest dir
func checkDir(dirpath string) bool {
	// 判断该文件夹是否在被排除的范围之内
	for _, dir := range nodirs {
		if rootPath+dir == dirpath {
			return false
		}
	}
	return true
}

func addLineNum(num int) {
	// 获取锁
	mutex.Lock()
	// defer语句在函数返回时调用, 确保锁被释放
	defer mutex.Unlock()
	linesum += num
}

// if error happened, throw a panic, and the panic will be recover in defer function
func checkerr(err error) {
	if err != nil {
		// 在发生错误时调用panic, 程序将立即停止正常执行, 开始沿调用栈往上抛, 直到遇到recover
		// 对于java程序员, 可以将panic类比为exception, 而recover则是try...catch
		panic(err.Error())
	}
}