gopl-zh.github.com/ch8/ch8-08.html

2221 lines
71 KiB
HTML
Raw Normal View History

2015-12-09 07:57:17 +00:00
<!DOCTYPE HTML>
<html lang="zh-tw" >
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
2015-12-31 08:20:27 +00:00
<title>示例: 併發的字典遍歷 | Go语言圣经</title>
2015-12-09 07:57:17 +00:00
<meta content="text/html; charset=utf-8" http-equiv="Content-Type">
<meta name="description" content="">
<meta name="generator" content="GitBook 2.5.2">
<meta name="HandheldFriendly" content="true"/>
<meta name="viewport" content="width=device-width, initial-scale=1, user-scalable=no">
<meta name="apple-mobile-web-app-capable" content="yes">
<meta name="apple-mobile-web-app-status-bar-style" content="black">
<link rel="apple-touch-icon-precomposed" sizes="152x152" href="../gitbook/images/apple-touch-icon-precomposed-152.png">
<link rel="shortcut icon" href="../gitbook/images/favicon.ico" type="image/x-icon">
<link rel="stylesheet" href="../gitbook/style.css">
2015-12-28 08:08:26 +00:00
<link rel="stylesheet" href="../gitbook/plugins/gitbook-plugin-katex/katex.min.css">
2015-12-09 07:57:17 +00:00
<link rel="stylesheet" href="../gitbook/plugins/gitbook-plugin-highlight/website.css">
<link rel="stylesheet" href="../gitbook/plugins/gitbook-plugin-fontsettings/website.css">
<link rel="next" href="../ch8/ch8-09.html" />
<link rel="prev" href="../ch8/ch8-07.html" />
</head>
<body>
2015-12-31 08:20:27 +00:00
<div class="book" data-level="8.8" data-chapter-title="示例: 併發的字典遍歷" data-filepath="ch8/ch8-08.md" data-basepath=".." data-revision="Thu Dec 31 2015 16:18:40 GMT+0800 (中国标准时间)">
2015-12-09 07:57:17 +00:00
<div class="book-summary">
<nav role="navigation">
<ul class="summary">
<li class="chapter " data-level="0" data-path="index.html">
<a href="../index.html">
<i class="fa fa-check"></i>
前言
</a>
<ul class="articles">
<li class="chapter " data-level="0.1" data-path="ch0/ch0-01.html">
<a href="../ch0/ch0-01.html">
<i class="fa fa-check"></i>
<b>0.1.</b>
Go語言起源
</a>
</li>
<li class="chapter " data-level="0.2" data-path="ch0/ch0-02.html">
<a href="../ch0/ch0-02.html">
<i class="fa fa-check"></i>
<b>0.2.</b>
Go語言項目
</a>
</li>
<li class="chapter " data-level="0.3" data-path="ch0/ch0-03.html">
<a href="../ch0/ch0-03.html">
<i class="fa fa-check"></i>
<b>0.3.</b>
本書的組織
</a>
</li>
<li class="chapter " data-level="0.4" data-path="ch0/ch0-04.html">
<a href="../ch0/ch0-04.html">
<i class="fa fa-check"></i>
<b>0.4.</b>
更多的信息
</a>
</li>
<li class="chapter " data-level="0.5" data-path="ch0/ch0-05.html">
<a href="../ch0/ch0-05.html">
<i class="fa fa-check"></i>
<b>0.5.</b>
2015-12-21 04:55:18 +00:00
致謝
2015-12-09 07:57:17 +00:00
</a>
</li>
</ul>
</li>
<li class="chapter " data-level="1" data-path="ch1/ch1.html">
<a href="../ch1/ch1.html">
<i class="fa fa-check"></i>
<b>1.</b>
入門
</a>
<ul class="articles">
<li class="chapter " data-level="1.1" data-path="ch1/ch1-01.html">
<a href="../ch1/ch1-01.html">
<i class="fa fa-check"></i>
<b>1.1.</b>
Hello, World
</a>
</li>
<li class="chapter " data-level="1.2" data-path="ch1/ch1-02.html">
<a href="../ch1/ch1-02.html">
<i class="fa fa-check"></i>
<b>1.2.</b>
命令行參數
</a>
</li>
<li class="chapter " data-level="1.3" data-path="ch1/ch1-03.html">
<a href="../ch1/ch1-03.html">
<i class="fa fa-check"></i>
<b>1.3.</b>
2015-12-21 04:55:18 +00:00
査找重複的行
2015-12-09 07:57:17 +00:00
</a>
</li>
<li class="chapter " data-level="1.4" data-path="ch1/ch1-04.html">
<a href="../ch1/ch1-04.html">
<i class="fa fa-check"></i>
<b>1.4.</b>
2015-12-21 04:55:18 +00:00
GIF動畵
2015-12-09 07:57:17 +00:00
</a>
</li>
<li class="chapter " data-level="1.5" data-path="ch1/ch1-05.html">
<a href="../ch1/ch1-05.html">
<i class="fa fa-check"></i>
<b>1.5.</b>
2015-12-28 08:08:26 +00:00
獲取URL
2015-12-09 07:57:17 +00:00
</a>
</li>
<li class="chapter " data-level="1.6" data-path="ch1/ch1-06.html">
<a href="../ch1/ch1-06.html">
<i class="fa fa-check"></i>
<b>1.6.</b>
2015-12-28 08:08:26 +00:00
併發獲取多個URL
2015-12-09 07:57:17 +00:00
</a>
</li>
<li class="chapter " data-level="1.7" data-path="ch1/ch1-07.html">
<a href="../ch1/ch1-07.html">
<i class="fa fa-check"></i>
<b>1.7.</b>
Web服務
</a>
</li>
<li class="chapter " data-level="1.8" data-path="ch1/ch1-08.html">
<a href="../ch1/ch1-08.html">
<i class="fa fa-check"></i>
<b>1.8.</b>
本章要點
</a>
</li>
</ul>
</li>
<li class="chapter " data-level="2" data-path="ch2/ch2.html">
<a href="../ch2/ch2.html">
<i class="fa fa-check"></i>
<b>2.</b>
程序結構
</a>
<ul class="articles">
<li class="chapter " data-level="2.1" data-path="ch2/ch2-01.html">
<a href="../ch2/ch2-01.html">
<i class="fa fa-check"></i>
<b>2.1.</b>
命名
</a>
</li>
<li class="chapter " data-level="2.2" data-path="ch2/ch2-02.html">
<a href="../ch2/ch2-02.html">
<i class="fa fa-check"></i>
<b>2.2.</b>
聲明
</a>
</li>
<li class="chapter " data-level="2.3" data-path="ch2/ch2-03.html">
<a href="../ch2/ch2-03.html">
<i class="fa fa-check"></i>
<b>2.3.</b>
變量
</a>
</li>
<li class="chapter " data-level="2.4" data-path="ch2/ch2-04.html">
<a href="../ch2/ch2-04.html">
<i class="fa fa-check"></i>
<b>2.4.</b>
賦值
</a>
</li>
<li class="chapter " data-level="2.5" data-path="ch2/ch2-05.html">
<a href="../ch2/ch2-05.html">
<i class="fa fa-check"></i>
<b>2.5.</b>
類型
</a>
</li>
<li class="chapter " data-level="2.6" data-path="ch2/ch2-06.html">
<a href="../ch2/ch2-06.html">
<i class="fa fa-check"></i>
<b>2.6.</b>
包和文件
</a>
</li>
<li class="chapter " data-level="2.7" data-path="ch2/ch2-07.html">
<a href="../ch2/ch2-07.html">
<i class="fa fa-check"></i>
<b>2.7.</b>
作用域
</a>
</li>
</ul>
</li>
<li class="chapter " data-level="3" data-path="ch3/ch3.html">
<a href="../ch3/ch3.html">
<i class="fa fa-check"></i>
<b>3.</b>
基礎數據類型
</a>
<ul class="articles">
<li class="chapter " data-level="3.1" data-path="ch3/ch3-01.html">
<a href="../ch3/ch3-01.html">
<i class="fa fa-check"></i>
<b>3.1.</b>
整型
</a>
</li>
<li class="chapter " data-level="3.2" data-path="ch3/ch3-02.html">
<a href="../ch3/ch3-02.html">
<i class="fa fa-check"></i>
<b>3.2.</b>
浮點數
</a>
</li>
<li class="chapter " data-level="3.3" data-path="ch3/ch3-03.html">
<a href="../ch3/ch3-03.html">
<i class="fa fa-check"></i>
<b>3.3.</b>
2015-12-21 04:55:18 +00:00
複數
2015-12-09 07:57:17 +00:00
</a>
</li>
<li class="chapter " data-level="3.4" data-path="ch3/ch3-04.html">
<a href="../ch3/ch3-04.html">
<i class="fa fa-check"></i>
<b>3.4.</b>
2015-12-21 04:55:18 +00:00
布爾型
2015-12-09 07:57:17 +00:00
</a>
</li>
<li class="chapter " data-level="3.5" data-path="ch3/ch3-05.html">
<a href="../ch3/ch3-05.html">
<i class="fa fa-check"></i>
<b>3.5.</b>
字符串
</a>
</li>
<li class="chapter " data-level="3.6" data-path="ch3/ch3-06.html">
<a href="../ch3/ch3-06.html">
<i class="fa fa-check"></i>
<b>3.6.</b>
常量
</a>
</li>
</ul>
</li>
<li class="chapter " data-level="4" data-path="ch4/ch4.html">
<a href="../ch4/ch4.html">
<i class="fa fa-check"></i>
<b>4.</b>
2015-12-21 04:55:18 +00:00
複合數據類型
2015-12-09 07:57:17 +00:00
</a>
<ul class="articles">
<li class="chapter " data-level="4.1" data-path="ch4/ch4-01.html">
<a href="../ch4/ch4-01.html">
<i class="fa fa-check"></i>
<b>4.1.</b>
數組
</a>
</li>
<li class="chapter " data-level="4.2" data-path="ch4/ch4-02.html">
<a href="../ch4/ch4-02.html">
<i class="fa fa-check"></i>
<b>4.2.</b>
2015-12-31 08:20:27 +00:00
Slice
2015-12-09 07:57:17 +00:00
</a>
</li>
<li class="chapter " data-level="4.3" data-path="ch4/ch4-03.html">
<a href="../ch4/ch4-03.html">
<i class="fa fa-check"></i>
<b>4.3.</b>
2015-12-31 08:20:27 +00:00
Map
2015-12-09 07:57:17 +00:00
</a>
</li>
<li class="chapter " data-level="4.4" data-path="ch4/ch4-04.html">
<a href="../ch4/ch4-04.html">
<i class="fa fa-check"></i>
<b>4.4.</b>
結構體
</a>
</li>
<li class="chapter " data-level="4.5" data-path="ch4/ch4-05.html">
<a href="../ch4/ch4-05.html">
<i class="fa fa-check"></i>
<b>4.5.</b>
JSON
</a>
</li>
<li class="chapter " data-level="4.6" data-path="ch4/ch4-06.html">
<a href="../ch4/ch4-06.html">
<i class="fa fa-check"></i>
<b>4.6.</b>
文本和HTML模闆
</a>
</li>
</ul>
</li>
<li class="chapter " data-level="5" data-path="ch5/ch5.html">
<a href="../ch5/ch5.html">
<i class="fa fa-check"></i>
<b>5.</b>
函數
</a>
<ul class="articles">
<li class="chapter " data-level="5.1" data-path="ch5/ch5-01.html">
<a href="../ch5/ch5-01.html">
<i class="fa fa-check"></i>
<b>5.1.</b>
函數聲明
</a>
</li>
<li class="chapter " data-level="5.2" data-path="ch5/ch5-02.html">
<a href="../ch5/ch5-02.html">
<i class="fa fa-check"></i>
<b>5.2.</b>
遞歸
</a>
</li>
<li class="chapter " data-level="5.3" data-path="ch5/ch5-03.html">
<a href="../ch5/ch5-03.html">
<i class="fa fa-check"></i>
<b>5.3.</b>
多返迴值
</a>
</li>
<li class="chapter " data-level="5.4" data-path="ch5/ch5-04.html">
<a href="../ch5/ch5-04.html">
<i class="fa fa-check"></i>
<b>5.4.</b>
錯誤
</a>
</li>
<li class="chapter " data-level="5.5" data-path="ch5/ch5-05.html">
<a href="../ch5/ch5-05.html">
<i class="fa fa-check"></i>
<b>5.5.</b>
函數值
</a>
</li>
<li class="chapter " data-level="5.6" data-path="ch5/ch5-06.html">
<a href="../ch5/ch5-06.html">
<i class="fa fa-check"></i>
<b>5.6.</b>
匿名函數
</a>
</li>
<li class="chapter " data-level="5.7" data-path="ch5/ch5-07.html">
<a href="../ch5/ch5-07.html">
<i class="fa fa-check"></i>
<b>5.7.</b>
可變參數
</a>
</li>
<li class="chapter " data-level="5.8" data-path="ch5/ch5-08.html">
<a href="../ch5/ch5-08.html">
<i class="fa fa-check"></i>
<b>5.8.</b>
Deferred函數
</a>
</li>
<li class="chapter " data-level="5.9" data-path="ch5/ch5-09.html">
<a href="../ch5/ch5-09.html">
<i class="fa fa-check"></i>
<b>5.9.</b>
Panic異常
</a>
</li>
<li class="chapter " data-level="5.10" data-path="ch5/ch5-10.html">
<a href="../ch5/ch5-10.html">
<i class="fa fa-check"></i>
<b>5.10.</b>
2015-12-28 08:08:26 +00:00
Recover捕獲異常
2015-12-09 07:57:17 +00:00
</a>
</li>
</ul>
</li>
<li class="chapter " data-level="6" data-path="ch6/ch6.html">
<a href="../ch6/ch6.html">
<i class="fa fa-check"></i>
<b>6.</b>
方法
</a>
<ul class="articles">
<li class="chapter " data-level="6.1" data-path="ch6/ch6-01.html">
<a href="../ch6/ch6-01.html">
<i class="fa fa-check"></i>
<b>6.1.</b>
方法聲明
</a>
</li>
<li class="chapter " data-level="6.2" data-path="ch6/ch6-02.html">
<a href="../ch6/ch6-02.html">
<i class="fa fa-check"></i>
<b>6.2.</b>
2015-12-21 04:55:18 +00:00
基於指針對象的方法
2015-12-09 07:57:17 +00:00
</a>
</li>
<li class="chapter " data-level="6.3" data-path="ch6/ch6-03.html">
<a href="../ch6/ch6-03.html">
<i class="fa fa-check"></i>
<b>6.3.</b>
通過嵌入結構體來擴展類型
</a>
</li>
<li class="chapter " data-level="6.4" data-path="ch6/ch6-04.html">
<a href="../ch6/ch6-04.html">
<i class="fa fa-check"></i>
<b>6.4.</b>
2015-12-21 04:55:18 +00:00
方法值和方法表達式
2015-12-09 07:57:17 +00:00
</a>
</li>
<li class="chapter " data-level="6.5" data-path="ch6/ch6-05.html">
<a href="../ch6/ch6-05.html">
<i class="fa fa-check"></i>
<b>6.5.</b>
示例: Bit數組
</a>
</li>
<li class="chapter " data-level="6.6" data-path="ch6/ch6-06.html">
<a href="../ch6/ch6-06.html">
<i class="fa fa-check"></i>
<b>6.6.</b>
封裝
</a>
</li>
</ul>
</li>
<li class="chapter " data-level="7" data-path="ch7/ch7.html">
<a href="../ch7/ch7.html">
<i class="fa fa-check"></i>
<b>7.</b>
接口
</a>
<ul class="articles">
<li class="chapter " data-level="7.1" data-path="ch7/ch7-01.html">
<a href="../ch7/ch7-01.html">
<i class="fa fa-check"></i>
<b>7.1.</b>
2015-12-21 04:55:18 +00:00
接口是合約
2015-12-09 07:57:17 +00:00
</a>
</li>
<li class="chapter " data-level="7.2" data-path="ch7/ch7-02.html">
<a href="../ch7/ch7-02.html">
<i class="fa fa-check"></i>
<b>7.2.</b>
接口類型
</a>
</li>
<li class="chapter " data-level="7.3" data-path="ch7/ch7-03.html">
<a href="../ch7/ch7-03.html">
<i class="fa fa-check"></i>
<b>7.3.</b>
實現接口的條件
</a>
</li>
<li class="chapter " data-level="7.4" data-path="ch7/ch7-04.html">
<a href="../ch7/ch7-04.html">
<i class="fa fa-check"></i>
<b>7.4.</b>
flag.Value接口
</a>
</li>
<li class="chapter " data-level="7.5" data-path="ch7/ch7-05.html">
<a href="../ch7/ch7-05.html">
<i class="fa fa-check"></i>
<b>7.5.</b>
接口值
</a>
</li>
<li class="chapter " data-level="7.6" data-path="ch7/ch7-06.html">
<a href="../ch7/ch7-06.html">
<i class="fa fa-check"></i>
<b>7.6.</b>
sort.Interface接口
</a>
</li>
<li class="chapter " data-level="7.7" data-path="ch7/ch7-07.html">
<a href="../ch7/ch7-07.html">
<i class="fa fa-check"></i>
<b>7.7.</b>
http.Handler接口
</a>
</li>
<li class="chapter " data-level="7.8" data-path="ch7/ch7-08.html">
<a href="../ch7/ch7-08.html">
<i class="fa fa-check"></i>
<b>7.8.</b>
error接口
</a>
</li>
<li class="chapter " data-level="7.9" data-path="ch7/ch7-09.html">
<a href="../ch7/ch7-09.html">
<i class="fa fa-check"></i>
<b>7.9.</b>
2015-12-21 04:55:18 +00:00
示例: 表達式求值
2015-12-09 07:57:17 +00:00
</a>
</li>
<li class="chapter " data-level="7.10" data-path="ch7/ch7-10.html">
<a href="../ch7/ch7-10.html">
<i class="fa fa-check"></i>
<b>7.10.</b>
類型斷言
</a>
</li>
<li class="chapter " data-level="7.11" data-path="ch7/ch7-11.html">
<a href="../ch7/ch7-11.html">
<i class="fa fa-check"></i>
<b>7.11.</b>
2015-12-21 04:55:18 +00:00
基於類型斷言識别錯誤類型
2015-12-09 07:57:17 +00:00
</a>
</li>
<li class="chapter " data-level="7.12" data-path="ch7/ch7-12.html">
<a href="../ch7/ch7-12.html">
<i class="fa fa-check"></i>
<b>7.12.</b>
通過類型斷言査詢接口
</a>
</li>
<li class="chapter " data-level="7.13" data-path="ch7/ch7-13.html">
<a href="../ch7/ch7-13.html">
<i class="fa fa-check"></i>
<b>7.13.</b>
類型分支
</a>
</li>
<li class="chapter " data-level="7.14" data-path="ch7/ch7-14.html">
<a href="../ch7/ch7-14.html">
<i class="fa fa-check"></i>
<b>7.14.</b>
示例: 基於標記的XML解碼
</a>
</li>
<li class="chapter " data-level="7.15" data-path="ch7/ch7-15.html">
<a href="../ch7/ch7-15.html">
<i class="fa fa-check"></i>
<b>7.15.</b>
補充幾點
</a>
</li>
</ul>
</li>
<li class="chapter " data-level="8" data-path="ch8/ch8.html">
<a href="../ch8/ch8.html">
<i class="fa fa-check"></i>
<b>8.</b>
Goroutines和Channels
</a>
<ul class="articles">
<li class="chapter " data-level="8.1" data-path="ch8/ch8-01.html">
<a href="../ch8/ch8-01.html">
<i class="fa fa-check"></i>
<b>8.1.</b>
Goroutines
</a>
</li>
<li class="chapter " data-level="8.2" data-path="ch8/ch8-02.html">
<a href="../ch8/ch8-02.html">
<i class="fa fa-check"></i>
<b>8.2.</b>
2015-12-21 04:55:18 +00:00
示例: 併發的Clock服務
2015-12-09 07:57:17 +00:00
</a>
</li>
<li class="chapter " data-level="8.3" data-path="ch8/ch8-03.html">
<a href="../ch8/ch8-03.html">
<i class="fa fa-check"></i>
<b>8.3.</b>
2015-12-21 04:55:18 +00:00
示例: 併發的Echo服務
2015-12-09 07:57:17 +00:00
</a>
</li>
<li class="chapter " data-level="8.4" data-path="ch8/ch8-04.html">
<a href="../ch8/ch8-04.html">
<i class="fa fa-check"></i>
<b>8.4.</b>
Channels
</a>
</li>
<li class="chapter " data-level="8.5" data-path="ch8/ch8-05.html">
<a href="../ch8/ch8-05.html">
<i class="fa fa-check"></i>
<b>8.5.</b>
併行的循環
</a>
</li>
<li class="chapter " data-level="8.6" data-path="ch8/ch8-06.html">
<a href="../ch8/ch8-06.html">
<i class="fa fa-check"></i>
<b>8.6.</b>
2015-12-21 04:55:18 +00:00
示例: 併發的Web爬蟲
2015-12-09 07:57:17 +00:00
</a>
</li>
<li class="chapter " data-level="8.7" data-path="ch8/ch8-07.html">
<a href="../ch8/ch8-07.html">
<i class="fa fa-check"></i>
<b>8.7.</b>
2015-12-21 04:55:18 +00:00
基於select的多路複用
2015-12-09 07:57:17 +00:00
</a>
</li>
<li class="chapter active" data-level="8.8" data-path="ch8/ch8-08.html">
<a href="../ch8/ch8-08.html">
<i class="fa fa-check"></i>
<b>8.8.</b>
2015-12-21 04:55:18 +00:00
示例: 併發的字典遍歷
2015-12-09 07:57:17 +00:00
</a>
</li>
<li class="chapter " data-level="8.9" data-path="ch8/ch8-09.html">
<a href="../ch8/ch8-09.html">
<i class="fa fa-check"></i>
<b>8.9.</b>
2015-12-28 08:08:26 +00:00
併發的退出
2015-12-09 07:57:17 +00:00
</a>
</li>
<li class="chapter " data-level="8.10" data-path="ch8/ch8-10.html">
<a href="../ch8/ch8-10.html">
<i class="fa fa-check"></i>
<b>8.10.</b>
示例: 聊天服務
</a>
</li>
</ul>
</li>
<li class="chapter " data-level="9" data-path="ch9/ch9.html">
<a href="../ch9/ch9.html">
<i class="fa fa-check"></i>
<b>9.</b>
2015-12-21 04:55:18 +00:00
基於共享變量的併發
2015-12-09 07:57:17 +00:00
</a>
<ul class="articles">
<li class="chapter " data-level="9.1" data-path="ch9/ch9-01.html">
<a href="../ch9/ch9-01.html">
<i class="fa fa-check"></i>
<b>9.1.</b>
競爭條件
</a>
</li>
<li class="chapter " data-level="9.2" data-path="ch9/ch9-02.html">
<a href="../ch9/ch9-02.html">
<i class="fa fa-check"></i>
<b>9.2.</b>
sync.Mutex互斥鎖
</a>
</li>
<li class="chapter " data-level="9.3" data-path="ch9/ch9-03.html">
<a href="../ch9/ch9-03.html">
<i class="fa fa-check"></i>
<b>9.3.</b>
sync.RWMutex讀寫鎖
</a>
</li>
<li class="chapter " data-level="9.4" data-path="ch9/ch9-04.html">
<a href="../ch9/ch9-04.html">
<i class="fa fa-check"></i>
<b>9.4.</b>
2015-12-21 04:55:18 +00:00
內存同步
2015-12-09 07:57:17 +00:00
</a>
</li>
<li class="chapter " data-level="9.5" data-path="ch9/ch9-05.html">
<a href="../ch9/ch9-05.html">
<i class="fa fa-check"></i>
<b>9.5.</b>
sync.Once初始化
</a>
</li>
<li class="chapter " data-level="9.6" data-path="ch9/ch9-06.html">
<a href="../ch9/ch9-06.html">
<i class="fa fa-check"></i>
<b>9.6.</b>
競爭條件檢測
</a>
</li>
<li class="chapter " data-level="9.7" data-path="ch9/ch9-07.html">
<a href="../ch9/ch9-07.html">
<i class="fa fa-check"></i>
<b>9.7.</b>
2015-12-21 04:55:18 +00:00
示例: 併發的非阻塞緩存
2015-12-09 07:57:17 +00:00
</a>
</li>
<li class="chapter " data-level="9.8" data-path="ch9/ch9-08.html">
<a href="../ch9/ch9-08.html">
<i class="fa fa-check"></i>
<b>9.8.</b>
2015-12-21 04:55:18 +00:00
Goroutines和線程
2015-12-09 07:57:17 +00:00
</a>
</li>
</ul>
</li>
<li class="chapter " data-level="10" data-path="ch10/ch10.html">
<a href="../ch10/ch10.html">
<i class="fa fa-check"></i>
<b>10.</b>
包和工具
</a>
<ul class="articles">
<li class="chapter " data-level="10.1" data-path="ch10/ch10-01.html">
<a href="../ch10/ch10-01.html">
<i class="fa fa-check"></i>
<b>10.1.</b>
簡介
</a>
</li>
<li class="chapter " data-level="10.2" data-path="ch10/ch10-02.html">
<a href="../ch10/ch10-02.html">
<i class="fa fa-check"></i>
<b>10.2.</b>
導入路徑
</a>
</li>
<li class="chapter " data-level="10.3" data-path="ch10/ch10-03.html">
<a href="../ch10/ch10-03.html">
<i class="fa fa-check"></i>
<b>10.3.</b>
包聲明
</a>
</li>
<li class="chapter " data-level="10.4" data-path="ch10/ch10-04.html">
<a href="../ch10/ch10-04.html">
<i class="fa fa-check"></i>
<b>10.4.</b>
導入聲明
</a>
</li>
<li class="chapter " data-level="10.5" data-path="ch10/ch10-05.html">
<a href="../ch10/ch10-05.html">
<i class="fa fa-check"></i>
<b>10.5.</b>
匿名導入
</a>
</li>
<li class="chapter " data-level="10.6" data-path="ch10/ch10-06.html">
<a href="../ch10/ch10-06.html">
<i class="fa fa-check"></i>
<b>10.6.</b>
包和命名
</a>
</li>
<li class="chapter " data-level="10.7" data-path="ch10/ch10-07.html">
<a href="../ch10/ch10-07.html">
<i class="fa fa-check"></i>
<b>10.7.</b>
工具
</a>
</li>
</ul>
</li>
<li class="chapter " data-level="11" data-path="ch11/ch11.html">
<a href="../ch11/ch11.html">
<i class="fa fa-check"></i>
<b>11.</b>
測試
</a>
<ul class="articles">
<li class="chapter " data-level="11.1" data-path="ch11/ch11-01.html">
<a href="../ch11/ch11-01.html">
<i class="fa fa-check"></i>
<b>11.1.</b>
go test
</a>
</li>
<li class="chapter " data-level="11.2" data-path="ch11/ch11-02.html">
<a href="../ch11/ch11-02.html">
<i class="fa fa-check"></i>
<b>11.2.</b>
測試函數
</a>
</li>
<li class="chapter " data-level="11.3" data-path="ch11/ch11-03.html">
<a href="../ch11/ch11-03.html">
<i class="fa fa-check"></i>
<b>11.3.</b>
測試覆蓋率
</a>
</li>
<li class="chapter " data-level="11.4" data-path="ch11/ch11-04.html">
<a href="../ch11/ch11-04.html">
<i class="fa fa-check"></i>
<b>11.4.</b>
基準測試
</a>
</li>
<li class="chapter " data-level="11.5" data-path="ch11/ch11-05.html">
<a href="../ch11/ch11-05.html">
<i class="fa fa-check"></i>
<b>11.5.</b>
剖析
</a>
</li>
<li class="chapter " data-level="11.6" data-path="ch11/ch11-06.html">
<a href="../ch11/ch11-06.html">
<i class="fa fa-check"></i>
<b>11.6.</b>
示例函數
</a>
</li>
</ul>
</li>
<li class="chapter " data-level="12" data-path="ch12/ch12.html">
<a href="../ch12/ch12.html">
<i class="fa fa-check"></i>
<b>12.</b>
反射
</a>
<ul class="articles">
<li class="chapter " data-level="12.1" data-path="ch12/ch12-01.html">
<a href="../ch12/ch12-01.html">
<i class="fa fa-check"></i>
<b>12.1.</b>
2015-12-21 04:55:18 +00:00
爲何需要反射?
2015-12-09 07:57:17 +00:00
</a>
</li>
<li class="chapter " data-level="12.2" data-path="ch12/ch12-02.html">
<a href="../ch12/ch12-02.html">
<i class="fa fa-check"></i>
<b>12.2.</b>
reflect.Type和reflect.Value
</a>
</li>
<li class="chapter " data-level="12.3" data-path="ch12/ch12-03.html">
<a href="../ch12/ch12-03.html">
<i class="fa fa-check"></i>
<b>12.3.</b>
Display遞歸打印
</a>
</li>
<li class="chapter " data-level="12.4" data-path="ch12/ch12-04.html">
<a href="../ch12/ch12-04.html">
<i class="fa fa-check"></i>
<b>12.4.</b>
2015-12-21 04:55:18 +00:00
示例: 編碼S表達式
2015-12-09 07:57:17 +00:00
</a>
</li>
<li class="chapter " data-level="12.5" data-path="ch12/ch12-05.html">
<a href="../ch12/ch12-05.html">
<i class="fa fa-check"></i>
<b>12.5.</b>
通過reflect.Value脩改值
</a>
</li>
<li class="chapter " data-level="12.6" data-path="ch12/ch12-06.html">
<a href="../ch12/ch12-06.html">
<i class="fa fa-check"></i>
<b>12.6.</b>
2015-12-21 04:55:18 +00:00
示例: 解碼S表達式
2015-12-09 07:57:17 +00:00
</a>
</li>
<li class="chapter " data-level="12.7" data-path="ch12/ch12-07.html">
<a href="../ch12/ch12-07.html">
<i class="fa fa-check"></i>
<b>12.7.</b>
2015-12-28 08:08:26 +00:00
獲取結構體字段標識
2015-12-09 07:57:17 +00:00
</a>
</li>
<li class="chapter " data-level="12.8" data-path="ch12/ch12-08.html">
<a href="../ch12/ch12-08.html">
<i class="fa fa-check"></i>
<b>12.8.</b>
顯示一個類型的方法集
</a>
</li>
<li class="chapter " data-level="12.9" data-path="ch12/ch12-09.html">
<a href="../ch12/ch12-09.html">
<i class="fa fa-check"></i>
<b>12.9.</b>
幾點忠告
</a>
</li>
</ul>
</li>
<li class="chapter " data-level="13" data-path="ch13/ch13.html">
<a href="../ch13/ch13.html">
<i class="fa fa-check"></i>
<b>13.</b>
底層編程
</a>
<ul class="articles">
<li class="chapter " data-level="13.1" data-path="ch13/ch13-01.html">
<a href="../ch13/ch13-01.html">
<i class="fa fa-check"></i>
<b>13.1.</b>
unsafe.Sizeof, Alignof 和 Offsetof
</a>
</li>
<li class="chapter " data-level="13.2" data-path="ch13/ch13-02.html">
<a href="../ch13/ch13-02.html">
<i class="fa fa-check"></i>
<b>13.2.</b>
unsafe.Pointer
</a>
</li>
<li class="chapter " data-level="13.3" data-path="ch13/ch13-03.html">
<a href="../ch13/ch13-03.html">
<i class="fa fa-check"></i>
<b>13.3.</b>
示例: 深度相等判斷
</a>
</li>
<li class="chapter " data-level="13.4" data-path="ch13/ch13-04.html">
<a href="../ch13/ch13-04.html">
<i class="fa fa-check"></i>
<b>13.4.</b>
通過cgo調用C代碼
</a>
</li>
<li class="chapter " data-level="13.5" data-path="ch13/ch13-05.html">
<a href="../ch13/ch13-05.html">
<i class="fa fa-check"></i>
<b>13.5.</b>
幾點忠告
</a>
</li>
</ul>
</li>
2015-12-24 06:47:06 +00:00
<li class="chapter " data-level="14" data-path="CONTRIBUTORS.html">
2015-12-09 07:57:17 +00:00
2015-12-24 06:47:06 +00:00
<a href="../CONTRIBUTORS.html">
2015-12-09 07:57:17 +00:00
<i class="fa fa-check"></i>
2015-12-21 04:55:18 +00:00
<b>14.</b>
2015-12-09 07:57:17 +00:00
2015-12-24 06:47:06 +00:00
附録
2015-12-09 07:57:17 +00:00
</a>
</li>
<li class="divider"></li>
<li>
<a href="https://www.gitbook.com" target="blank" class="gitbook-link">
本書使用 GitBook 釋出
</a>
</li>
</ul>
</nav>
</div>
<div class="book-body">
<div class="body-inner">
<div class="book-header" role="navigation">
<!-- Actions Left -->
<!-- Title -->
<h1>
<i class="fa fa-circle-o-notch fa-spin"></i>
2015-12-31 08:20:27 +00:00
<a href="../" >Go语言圣经</a>
2015-12-09 07:57:17 +00:00
</h1>
</div>
<div class="page-wrapper" tabindex="-1" role="main">
<div class="page-inner">
<section class="normal" id="section-">
2015-12-21 04:55:18 +00:00
<h2 id="88-&#x793A;&#x4F8B;-&#x4F75;&#x767C;&#x7684;&#x5B57;&#x5178;&#x904D;&#x6B77;">8.8. &#x793A;&#x4F8B;: &#x4F75;&#x767C;&#x7684;&#x5B57;&#x5178;&#x904D;&#x6B77;</h2>
<p>&#x5728;&#x672C;&#x5C0F;&#x7BC0;&#x4E2D;&#xFF0C;&#x6211;&#x5011;&#x6703;&#x5275;&#x5EFA;&#x4E00;&#x500B;&#x7A0B;&#x5E8F;&#x4F86;&#x751F;&#x6210;&#x6307;&#x5B9A;&#x76EE;&#x9332;&#x7684;&#x786C;&#x76E4;&#x4F7F;&#x7528;&#x60C5;&#x6CC1;&#x5831;&#x544A;&#xFF0C;&#x9019;&#x500B;&#x7A0B;&#x5E8F;&#x548C;Unix&#x91CC;&#x7684;du&#x5DE5;&#x5177;&#x6BD4;&#x8F03;&#x76F8;&#x4F3C;&#x3002;&#x5927;&#x591A;&#x6578;&#x5DE5;&#x4F5C;&#x7528;&#x4E0B;&#x9762;&#x9019;&#x500B;walkDir&#x51FD;&#x6578;&#x4F86;&#x5B8C;&#x6210;&#xFF0C;&#x9019;&#x500B;&#x51FD;&#x6578;&#x4F7F;&#x7528;dirents&#x51FD;&#x6578;&#x4F86;&#x679A;&#x8209;&#x4E00;&#x500B;&#x76EE;&#x9332;&#x4E0B;&#x7684;&#x6240;&#x6709;&#x5165;&#x53E3;&#x3002;</p>
2015-12-14 04:08:47 +00:00
<pre><code class="lang-go">gopl.io/ch8/du1
<span class="hljs-comment">// walkDir recursively walks the file tree rooted at dir</span>
<span class="hljs-comment">// and sends the size of each found file on fileSizes.</span>
<span class="hljs-keyword">func</span> walkDir(dir <span class="hljs-typename">string</span>, fileSizes <span class="hljs-keyword">chan</span>&lt;- <span class="hljs-typename">int64</span>) {
<span class="hljs-keyword">for</span> _, entry := <span class="hljs-keyword">range</span> dirents(dir) {
<span class="hljs-keyword">if</span> entry.IsDir() {
subdir := filepath.Join(dir, entry.Name())
walkDir(subdir, fileSizes)
} <span class="hljs-keyword">else</span> {
fileSizes &lt;- entry.Size()
}
}
}
<span class="hljs-comment">// dirents returns the entries of directory dir.</span>
<span class="hljs-keyword">func</span> dirents(dir <span class="hljs-typename">string</span>) []os.FileInfo {
entries, err := ioutil.ReadDir(dir)
<span class="hljs-keyword">if</span> err != <span class="hljs-constant">nil</span> {
fmt.Fprintf(os.Stderr, <span class="hljs-string">&quot;du1: %v\n&quot;</span>, err)
<span class="hljs-keyword">return</span> <span class="hljs-constant">nil</span>
}
<span class="hljs-keyword">return</span> entries
}
</code></pre>
2015-12-21 04:55:18 +00:00
<p>ioutil.ReadDir&#x51FD;&#x6578;&#x6703;&#x8FD4;&#x8FF4;&#x4E00;&#x500B;os.FileInfo&#x985E;&#x578B;&#x7684;slice&#xFF0C;os.FileInfo&#x985E;&#x578B;&#x4E5F;&#x662F;os.Stat&#x9019;&#x500B;&#x51FD;&#x6578;&#x7684;&#x8FD4;&#x8FF4;&#x503C;&#x3002;&#x5C0D;&#x6BCF;&#x4E00;&#x500B;&#x5B50;&#x76EE;&#x9332;&#x800C;&#x8A00;&#xFF0C;walkDir&#x6703;&#x905E;&#x6B78;&#x5730;&#x8ABF;&#x7528;&#x5176;&#x81EA;&#x8EAB;&#xFF0C;&#x4F75;&#x4E14;&#x6703;&#x5C0D;&#x6BCF;&#x4E00;&#x500B;&#x6587;&#x4EF6;&#x4E5F;&#x905E;&#x6B78;&#x8ABF;&#x7528;&#x3002;walkDir&#x51FD;&#x6578;&#x6703;&#x5411;fileSizes&#x9019;&#x500B;channel&#x767C;&#x9001;&#x4E00;&#x689D;&#x6D88;&#x606F;&#x3002;&#x9019;&#x689D;&#x6D88;&#x606F;&#x5305;&#x542B;&#x4E86;&#x6587;&#x4EF6;&#x7684;&#x5B57;&#x7BC0;&#x5927;&#x5C0F;&#x3002;</p>
2015-12-28 08:08:26 +00:00
<p>&#x4E0B;&#x9762;&#x7684;&#x4E3B;&#x51FD;&#x6578;&#xFF0C;&#x7528;&#x4E86;&#x5169;&#x500B;goroutine&#x3002;&#x5F8C;&#x53F0;&#x7684;goroutine&#x8ABF;&#x7528;walkDir&#x4F86;&#x904D;&#x6B77;&#x547D;&#x4EE4;&#x884C;&#x7D66;&#x51FA;&#x7684;&#x6BCF;&#x4E00;&#x500B;&#x8DEF;&#x5F91;&#x4F75;&#x6700;&#x7D42;&#x95DC;&#x9589;fileSizes&#x9019;&#x500B;channel&#x3002;&#x4E3B;goroutine&#x6703;&#x5C0D;&#x5176;&#x5F9E;channel&#x4E2D;&#x63A5;&#x6536;&#x5230;&#x7684;&#x6587;&#x4EF6;&#x5927;&#x5C0F;&#x9032;&#x884C;&#x7E8D;&#x52A0;&#xFF0C;&#x4F75;&#x8F38;&#x51FA;&#x5176;&#x548C;&#x3002;</p>
2015-12-14 04:08:47 +00:00
<pre><code class="lang-go"><span class="hljs-keyword">package</span> main
<span class="hljs-keyword">import</span> (
<span class="hljs-string">&quot;flag&quot;</span>
<span class="hljs-string">&quot;fmt&quot;</span>
<span class="hljs-string">&quot;io/ioutil&quot;</span>
<span class="hljs-string">&quot;os&quot;</span>
<span class="hljs-string">&quot;path/filepath&quot;</span>
)
<span class="hljs-keyword">func</span> main() {
<span class="hljs-comment">// Determine the initial directories.</span>
flag.Parse()
roots := flag.Args()
<span class="hljs-keyword">if</span> <span class="hljs-built_in">len</span>(roots) == <span class="hljs-number">0</span> {
roots = []<span class="hljs-typename">string</span>{<span class="hljs-string">&quot;.&quot;</span>}
}
<span class="hljs-comment">// Traverse the file tree.</span>
fileSizes := <span class="hljs-built_in">make</span>(<span class="hljs-keyword">chan</span> <span class="hljs-typename">int64</span>)
<span class="hljs-keyword">go</span> <span class="hljs-keyword">func</span>() {
<span class="hljs-keyword">for</span> _, root := <span class="hljs-keyword">range</span> roots {
walkDir(root, fileSizes)
}
<span class="hljs-built_in">close</span>(fileSizes)
}()
<span class="hljs-comment">// Print the results.</span>
<span class="hljs-keyword">var</span> nfiles, nbytes <span class="hljs-typename">int64</span>
<span class="hljs-keyword">for</span> size := <span class="hljs-keyword">range</span> fileSizes {
nfiles++
nbytes += size
}
printDiskUsage(nfiles, nbytes)
}
<span class="hljs-keyword">func</span> printDiskUsage(nfiles, nbytes <span class="hljs-typename">int64</span>) {
fmt.Printf(<span class="hljs-string">&quot;%d files %.1f GB\n&quot;</span>, nfiles, <span class="hljs-typename">float64</span>(nbytes)/<span class="hljs-number">1e9</span>)
}
</code></pre>
<p>&#x9019;&#x500B;&#x7A0B;&#x5E8F;&#x6703;&#x5728;&#x6253;&#x5370;&#x5176;&#x7D50;&#x679C;&#x4E4B;&#x524D;&#x5361;&#x4F4F;&#x5F88;&#x9577;&#x6642;&#x9593;&#x3002;</p>
<pre><code>$ go build gopl.io/ch8/du1
$ ./du1 $HOME /usr /bin /etc
213201 files 62.7 GB
2015-12-28 08:08:26 +00:00
</code></pre><p>&#x5982;&#x679C;&#x5728;&#x904B;&#x884C;&#x7684;&#x6642;&#x5019;&#x80FD;&#x5920;&#x8B93;&#x6211;&#x5011;&#x77E5;&#x9053;&#x8655;&#x7406;&#x9032;&#x5EA6;&#x7684;&#x8A71;&#x60F3;&#x5FC5;&#x66F4;&#x597D;&#x3002;&#x4F46;&#x662F;&#xFF0C;&#x5982;&#x679C;&#x7C21;&#x55AE;&#x5730;&#x628A;printDiskUsage&#x51FD;&#x6578;&#x8ABF;&#x7528;&#x79FB;&#x52D5;&#x5230;&#x5FAA;&#x74B0;&#x91CC;&#x6703;&#x5C0E;&#x81F4;&#x5176;&#x6253;&#x5370;&#x51FA;&#x6210;&#x767E;&#x4E0A;&#x97C6;&#x7684;&#x8F38;&#x51FA;&#x3002;</p>
<p>&#x4E0B;&#x9762;&#x9019;&#x500B;du&#x7684;&#x8B8A;&#x7A2E;&#x6703;&#x9593;&#x6B47;&#x6253;&#x5370;&#x5167;&#x5BB9;&#xFF0C;&#x4E0D;&#x904E;&#x96BB;&#x6709;&#x5728;&#x8ABF;&#x7528;&#x6642;&#x63D0;&#x4F9B;&#x4E86;-v&#x7684;flag&#x624D;&#x6703;&#x986F;&#x793A;&#x7A0B;&#x5E8F;&#x9032;&#x5EA6;&#x4FE1;&#x606F;&#x3002;&#x5728;roots&#x76EE;&#x9332;&#x4E0A;&#x5FAA;&#x74B0;&#x7684;&#x5F8C;&#x53F0;goroutine&#x5728;&#x9019;&#x91CC;&#x4FDD;&#x6301;&#x4E0D;&#x8B8A;&#x3002;&#x4E3B;goroutine&#x73FE;&#x5728;&#x4F7F;&#x7528;&#x4E86;&#x8A08;&#x6642;&#x5668;&#x4F86;&#x6BCF;500ms&#x751F;&#x6210;&#x4E8B;&#x4EF6;&#xFF0C;&#x7136;&#x5F8C;&#x7528;select&#x8A9E;&#x53E5;&#x4F86;&#x7B49;&#x5F85;&#x6587;&#x4EF6;&#x5927;&#x5C0F;&#x7684;&#x6D88;&#x606F;&#x4F86;&#x66F4;&#x65B0;&#x7E3D;&#x5927;&#x5C0F;&#x6578;&#x64DA;&#xFF0C;&#x6216;&#x8005;&#x4E00;&#x500B;&#x8A08;&#x6642;&#x5668;&#x7684;&#x4E8B;&#x4EF6;&#x4F86;&#x6253;&#x5370;&#x7576;&#x524D;&#x7684;&#x7E3D;&#x5927;&#x5C0F;&#x6578;&#x64DA;&#x3002;&#x5982;&#x679C;-v&#x7684;flag&#x5728;&#x904B;&#x884C;&#x6642;&#x6C92;&#x6709;&#x50B3;&#x5165;&#x7684;&#x8A71;&#xFF0C;tick&#x9019;&#x500B;channel&#x6703;&#x4FDD;&#x6301;&#x7232;nil&#xFF0C;&#x9019;&#x6A23;&#x5728;select&#x91CC;&#x7684;case&#x4E5F;&#x5C31;&#x76F8;&#x7576;&#x65BC;&#x88AB;&#x7981;&#x7528;&#x4E86;&#x3002;</p>
2015-12-14 04:08:47 +00:00
<pre><code class="lang-go">gopl.io/ch8/du2
<span class="hljs-keyword">var</span> verbose = flag.Bool(<span class="hljs-string">&quot;v&quot;</span>, <span class="hljs-constant">false</span>, <span class="hljs-string">&quot;show verbose progress messages&quot;</span>)
<span class="hljs-keyword">func</span> main() {
<span class="hljs-comment">// ...start background goroutine...</span>
<span class="hljs-comment">// Print the results periodically.</span>
<span class="hljs-keyword">var</span> tick &lt;-<span class="hljs-keyword">chan</span> time.Time
<span class="hljs-keyword">if</span> *verbose {
tick = time.Tick(<span class="hljs-number">500</span> * time.Millisecond)
}
<span class="hljs-keyword">var</span> nfiles, nbytes <span class="hljs-typename">int64</span>
loop:
<span class="hljs-keyword">for</span> {
<span class="hljs-keyword">select</span> {
<span class="hljs-keyword">case</span> size, ok := &lt;-fileSizes:
<span class="hljs-keyword">if</span> !ok {
<span class="hljs-keyword">break</span> loop <span class="hljs-comment">// fileSizes was closed</span>
}
nfiles++
nbytes += size
<span class="hljs-keyword">case</span> &lt;-tick:
printDiskUsage(nfiles, nbytes)
}
}
printDiskUsage(nfiles, nbytes) <span class="hljs-comment">// final totals</span>
}
</code></pre>
2015-12-28 08:08:26 +00:00
<p>&#x7531;&#x65BC;&#x6211;&#x5011;&#x7684;&#x7A0B;&#x5E8F;&#x4E0D;&#x518D;&#x4F7F;&#x7528;range&#x5FAA;&#x74B0;&#xFF0C;&#x7B2C;&#x4E00;&#x500B;select&#x7684;case&#x5FC5;&#x9B1A;&#x986F;&#x5F0F;&#x5730;&#x5224;&#x65B7;fileSizes&#x7684;channel&#x662F;&#x4E0D;&#x662F;&#x5DF2;&#x7D93;&#x88AB;&#x95DC;&#x9589;&#x4E86;&#xFF0C;&#x9019;&#x91CC;&#x53EF;&#x4EE5;&#x7528;&#x5230;channel&#x63A5;&#x6536;&#x7684;&#x4E8C;&#x503C;&#x5F62;&#x5F0F;&#x3002;&#x5982;&#x679C;channel&#x5DF2;&#x7D93;&#x88AB;&#x95DC;&#x9589;&#x4E86;&#x7684;&#x8A71;&#xFF0C;&#x7A0B;&#x5E8F;&#x6703;&#x76F4;&#x63A5;&#x9000;&#x51FA;&#x5FAA;&#x74B0;&#x3002;&#x9019;&#x91CC;&#x7684;break&#x8A9E;&#x53E5;&#x7528;&#x5230;&#x4E86;&#x6A19;&#x7C64;break&#xFF0C;&#x9019;&#x6A23;&#x53EF;&#x4EE5;&#x540C;&#x6642;&#x7D42;&#x7D50;select&#x548C;for&#x5169;&#x500B;&#x5FAA;&#x74B0;&#xFF1B;&#x5982;&#x679C;&#x6C92;&#x6709;&#x7528;&#x6A19;&#x7C64;&#x5C31;break&#x7684;&#x8A71;&#x96BB;&#x6703;&#x9000;&#x51FA;&#x5167;&#x5C64;&#x7684;select&#x5FAA;&#x74B0;&#xFF0C;&#x800C;&#x5916;&#x5C64;&#x7684;for&#x5FAA;&#x74B0;&#x6703;&#x4F7F;&#x4E4B;&#x9032;&#x5165;&#x4E0B;&#x4E00;&#x8F2A;select&#x5FAA;&#x74B0;&#x3002;</p>
2015-12-14 04:08:47 +00:00
<p>&#x73FE;&#x5728;&#x7A0B;&#x5E8F;&#x6703;&#x60A0;&#x9592;&#x5730;&#x7232;&#x6211;&#x5011;&#x6253;&#x5370;&#x66F4;&#x65B0;&#x6D41;&#xFF1A;</p>
<pre><code>$ go build gopl.io/ch8/du2
$ ./du2 -v $HOME /usr /bin /etc
28608 files 8.3 GB
54147 files 10.3 GB
93591 files 15.1 GB
127169 files 52.9 GB
175931 files 62.2 GB
213201 files 62.7 GB
2015-12-28 08:08:26 +00:00
</code></pre><p>&#x7136;&#x800C;&#x9019;&#x500B;&#x7A0B;&#x5E8F;&#x9084;&#x662F;&#x6703;&#x82B1;&#x4E0A;&#x5F88;&#x9577;&#x6642;&#x9593;&#x624D;&#x6703;&#x7D50;&#x675F;&#x3002;&#x7121;&#x6CD5;&#x5C0D;walkDir&#x505A;&#x4F75;&#x884C;&#x5316;&#x8655;&#x7406;&#x6C92;&#x4EC0;&#x9EBD;&#x522B;&#x7684;&#x539F;&#x56E0;&#xFF0C;&#x7121;&#x975E;&#x662F;&#x56E0;&#x7232;&#x78C1;&#x76E4;&#x7E6B;&#x7D71;&#x4F75;&#x884C;&#x9650;&#x88FD;&#x3002;&#x4E0B;&#x9762;&#x9019;&#x500B;&#x7B2C;&#x4E09;&#x500B;&#x7248;&#x672C;&#x7684;du&#xFF0C;&#x6703;&#x5C0D;&#x6BCF;&#x4E00;&#x500B;walkDir&#x7684;&#x8ABF;&#x7528;&#x5275;&#x5EFA;&#x4E00;&#x500B;&#x65B0;&#x7684;goroutine&#x3002;&#x5B83;&#x4F7F;&#x7528;sync.WaitGroup (&#xA7;8.5)&#x4F86;&#x5C0D;&#x4ECD;&#x820A;&#x6D3B;&#x8E8D;&#x7684;walkDir&#x8ABF;&#x7528;&#x9032;&#x884C;&#x8A08;&#x6578;&#xFF0C;&#x53E6;&#x4E00;&#x500B;goroutine&#x6703;&#x5728;&#x8A08;&#x6578;&#x5668;&#x6E1B;&#x7232;&#x96F6;&#x7684;&#x6642;&#x5019;&#x5C07;fileSizes&#x9019;&#x500B;channel&#x95DC;&#x9589;&#x3002;</p>
2015-12-14 04:08:47 +00:00
<pre><code class="lang-go">gopl.io/ch8/du3
<span class="hljs-keyword">func</span> main() {
<span class="hljs-comment">// ...determine roots...</span>
<span class="hljs-comment">// Traverse each root of the file tree in parallel.</span>
fileSizes := <span class="hljs-built_in">make</span>(<span class="hljs-keyword">chan</span> <span class="hljs-typename">int64</span>)
<span class="hljs-keyword">var</span> n sync.WaitGroup
<span class="hljs-keyword">for</span> _, root := <span class="hljs-keyword">range</span> roots {
n.Add(<span class="hljs-number">1</span>)
<span class="hljs-keyword">go</span> walkDir(root, &amp;n, fileSizes)
}
<span class="hljs-keyword">go</span> <span class="hljs-keyword">func</span>() {
n.Wait()
<span class="hljs-built_in">close</span>(fileSizes)
}()
<span class="hljs-comment">// ...select loop...</span>
}
<span class="hljs-keyword">func</span> walkDir(dir <span class="hljs-typename">string</span>, n *sync.WaitGroup, fileSizes <span class="hljs-keyword">chan</span>&lt;- <span class="hljs-typename">int64</span>) {
<span class="hljs-keyword">defer</span> n.Done()
<span class="hljs-keyword">for</span> _, entry := <span class="hljs-keyword">range</span> dirents(dir) {
<span class="hljs-keyword">if</span> entry.IsDir() {
n.Add(<span class="hljs-number">1</span>)
subdir := filepath.Join(dir, entry.Name())
<span class="hljs-keyword">go</span> walkDir(subdir, n, fileSizes)
} <span class="hljs-keyword">else</span> {
fileSizes &lt;- entry.Size()
}
}
}
</code></pre>
2015-12-21 04:55:18 +00:00
<p>&#x7531;&#x65BC;&#x9019;&#x500B;&#x7A0B;&#x5E8F;&#x5728;&#x9AD8;&#x5CEF;&#x671F;&#x6703;&#x5275;&#x5EFA;&#x6210;&#x767E;&#x4E0A;&#x97C6;&#x7684;goroutine&#xFF0C;&#x6211;&#x5011;&#x9700;&#x8981;&#x8129;&#x6539;dirents&#x51FD;&#x6578;&#xFF0C;&#x7528;&#x8A08;&#x6578;&#x4FE1;&#x865F;&#x91CF;&#x4F86;&#x963B;&#x6B62;&#x4ED6;&#x540C;&#x6642;&#x6253;&#x958B;&#x592A;&#x591A;&#x7684;&#x6587;&#x4EF6;&#xFF0C;&#x5C31;&#x50CF;&#x6211;&#x5011;&#x5728;8.7&#x7BC0;&#x4E2D;&#x7684;&#x4F75;&#x767C;&#x722C;&#x87F2;&#x4E00;&#x6A23;&#xFF1A;</p>
2015-12-14 04:08:47 +00:00
<pre><code class="lang-go"><span class="hljs-comment">// sema is a counting semaphore for limiting concurrency in dirents.</span>
<span class="hljs-keyword">var</span> sema = <span class="hljs-built_in">make</span>(<span class="hljs-keyword">chan</span> <span class="hljs-keyword">struct</span>{}, <span class="hljs-number">20</span>)
<span class="hljs-comment">// dirents returns the entries of directory dir.</span>
<span class="hljs-keyword">func</span> dirents(dir <span class="hljs-typename">string</span>) []os.FileInfo {
sema &lt;- <span class="hljs-keyword">struct</span>{}{} <span class="hljs-comment">// acquire token</span>
<span class="hljs-keyword">defer</span> <span class="hljs-keyword">func</span>() { &lt;-sema }() <span class="hljs-comment">// release token</span>
<span class="hljs-comment">// ...</span>
</code></pre>
2015-12-21 04:55:18 +00:00
<p>&#x9019;&#x500B;&#x7248;&#x672C;&#x6BD4;&#x4E4B;&#x524D;&#x90A3;&#x500B;&#x5FEB;&#x4E86;&#x597D;&#x5E7E;&#x500D;&#xFF0C;&#x76E1;&#x7BA1;&#x5176;&#x5177;&#x9AD4;&#x6548;&#x7387;&#x9084;&#x662F;&#x548C;&#x4F60;&#x7684;&#x904B;&#x884C;&#x74B0;&#x5883;&#xFF0C;&#x6A5F;&#x5668;&#x914D;&#x7F6E;&#x76F8;&#x95DC;&#x3002;</p>
2015-12-28 08:08:26 +00:00
<p>&#x7DF4;&#x7FD2;8.9: &#x7DE8;&#x5BEB;&#x4E00;&#x500B;du&#x5DE5;&#x5177;&#xFF0C;&#x6BCF;&#x9694;&#x4E00;&#x6BB5;&#x6642;&#x9593;&#x5C07;root&#x76EE;&#x9332;&#x4E0B;&#x7684;&#x76EE;&#x9332;&#x5927;&#x5C0F;&#x8A08;&#x7B97;&#x4F75;&#x986F;&#x793A;&#x51FA;&#x4F86;&#x3002;</p>
2015-12-09 07:57:17 +00:00
</section>
</div>
</div>
</div>
2015-12-21 04:55:18 +00:00
<a href="../ch8/ch8-07.html" class="navigation navigation-prev " aria-label="Previous page: 基於select的多路複用"><i class="fa fa-angle-left"></i></a>
2015-12-09 07:57:17 +00:00
2015-12-28 08:08:26 +00:00
<a href="../ch8/ch8-09.html" class="navigation navigation-next " aria-label="Next page: 併發的退出"><i class="fa fa-angle-right"></i></a>
2015-12-09 07:57:17 +00:00
</div>
</div>
<script src="../gitbook/app.js"></script>
<script src="../gitbook/plugins/gitbook-plugin-sharing/buttons.js"></script>
<script src="../gitbook/plugins/gitbook-plugin-fontsettings/buttons.js"></script>
<script>
require(["gitbook"], function(gitbook) {
2015-12-28 08:08:26 +00:00
var config = {"katex":{},"highlight":{},"sharing":{"facebook":true,"twitter":true,"google":false,"weibo":false,"instapaper":false,"vk":false,"all":["facebook","google","twitter","weibo","instapaper"]},"fontsettings":{"theme":"white","family":"sans","size":2}};
2015-12-09 07:57:17 +00:00
gitbook.start(config);
});
</script>
</body>
</html>