Rust-Helloworld - 汤汤（努力工作版）

Setup


`rustc`	`clang`	rust编译器
`cargo`	`make`	管理项目、依赖、构建、运行、测试、发布
`rustup`	`update-alternatives`	安装、更新工具链和版本

安装rustup

借助rustup管理工具链
可执行rustup update进行升级更新

安装方法

windows 下载地址

类unix安装命令 curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh

但是老报错👀，可能压缩包太大了，网络状况堪忧，推荐下一种方法

官方链接找到适合自己操作系统的压缩包下载、解压，然后运行sudo ./install.sh进行安装
- 即可获得编译器rustc、包管理器cargo
验证🥂🥂🥂

$ rustc --version
rustc 1.82.0 (f6e511eec 2024-10-15)
$ cargo --version
cargo 1.82.0 (8f40fc59f 2024-08-21)

cargo 使用准备

换国内源
- 在/home/.cargo/config.toml中添加

[source.crates-io]
replace-with = 'ustc'

[source.ustc]
registry = "sparse+https://mirrors.ustc.edu.cn/crates.io-index/"

添加环境变量
- cargo install rustfmt执行后，有一个warning：warning: be sure to add /home/lxh/.cargo/bin to your PATH to be able to run the installed binaries提示需要将bin加入环境变量
  - 查看当前环境变量echo $PATH
- 方法1：export PATH=/home/lxh/.cargo/bin:$PATH
  - 缺点：一次性修改
- 方法2：修改~/.bashrc文件，并终端执行$ source ~/.bashrc立即生效，且永久有效
- 方法3：修改/etc/profile，同2

配置编辑器

在vscode中装一个rust-analyzer插件，支持命令补全、代码检查

Cargo与Rust项目

项目管理

$ cargo -h
Rust's package manager

Usage: cargo [OPTIONS] [COMMAND]
       cargo [OPTIONS] -Zscript <MANIFEST_RS> [ARGS]...

Options:
  -V, --version             Print version info and exit
      --list                List installed commands
      --explain <CODE>      Provide a detailed explanation of a rustc error message
  -v, --verbose...          Use verbose output (-vv very verbose/build.rs output)
  -q, --quiet               Do not print cargo log messages
      --color <WHEN>        Coloring: auto, always, never
  -C <DIRECTORY>            Change to DIRECTORY before doing anything (nightly-only)
      --locked              Assert that `Cargo.lock` will remain unchanged
      --offline             Run without accessing the network
      --frozen              Equivalent to specifying both --locked and --offline
      --config <KEY=VALUE>  Override a configuration value
  -Z <FLAG>                 Unstable (nightly-only) flags to Cargo, see 'cargo -Z help' for
                            details
  -h, --help                Print help

Commands:
    build, b    Compile the current package
    check, c    Analyze the current package and report errors, but don't build object files
    clean       Remove the target directory
    doc, d      Build this package's and its dependencies' documentation
    new         Create a new cargo package
    init        Create a new cargo package in an existing directory
    add         Add dependencies to a manifest file
    remove      Remove dependencies from a manifest file
    run, r      Run a binary or example of the local package
    test, t     Run the tests
    bench       Run the benchmarks
    update      Update dependencies listed in Cargo.lock
    search      Search registry for crates
    publish     Package and upload this package to the registry
    install     Install a Rust binary
    uninstall   Uninstall a Rust binary
    ...         See all commands with --list

See 'cargo help <command>' for more information on a specific command.

0. init

sha1$ cargo init
    Creating binary (application) package
note: see more `Cargo.toml` keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

sha1$ tree 
.
├── Cargo.toml
└── src
    └── main.rs

1 directory, 2 files

sha1$ cat Cargo.toml 
[package]
name = "sha1"
version = "0.1.0"
edition = "2021"

[dependencies]

.toml配置文件
- 类似于Node.js的package.json
- [package]：项目名、版本、作者等元信息。
  - edition
    - 2015: Rust 1.0
    - 2018: Rust 1.31
    - 2021: Rust 1.56
- [dependencies]：依赖库，如 sha1 = "0.6"
crate
- 最小编译单元
- main.rs
  - 可执行程序入口，fn main()
  - binary crate
- lib.rs
  - library crate

1. run

fn main() {
    println!("Hello, world!");
}

sha1/src$ cargo run main.rs 
   Compiling sha1 v0.1.0 (/sha1)
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 5.66s
    Running `sha1 main.rs`
Hello, world!

Println!
- Rust宏是什么

# Cargo stores the result of the build in the target/debug directory.
/sha1$ tree
.
├── Cargo.lock
├── Cargo.toml
├── src
│   └── main.rs
└── target
    ├── CACHEDIR.TAG
    └── debug
        ├── build
        ├── deps
        │   ├── sha1-6468a928cc7d1c4c
        │   └── sha1-6468a928cc7d1c4c.d
        ├── examples
        ├── incremental
        │   └── sha1-3gwi201aeuma9
        │       ├── ...
        ├── sha1
        └── sha1.d

9 directories, 18 files

Our demo

use sha1::{Sha1, Digest};
use hex;

fn main() {
    let password = "hello";
    let hash = Sha1::digest(password.as_bytes());
    println!("Password: {}", password);
    println!("SHA1 hash (hex): {}", hex::encode(hash));
}

1. use

用于引入模块、结构体、函数、trait 或者常量到当前作用域

引入标准库

use std::collections::HashMap;//数据结构
use std::io::{self, Write，Read};//IO操作、引用多个
use std::fs::*;//文件操作、引用整个模块
use std::collections::HashMap as Map;//取别名

引入第三方库
- 需要在toml中先添加依赖
```
[dependencies]
regex = "1.9"
```
引入trait
- 相对复杂，结合例子来看：use sha1::{Sha1, Digest};,let hash = Sha1::digest(password.as_bytes());
- Sha1是一个结构体
- Digest是sha1库中的一个trait
  - fn digest()是其中的一个关联函数/静态方法
    - 关联函数：没有self参数，只能通过类型名调用

Sha1：引入类型，告诉编译器我要用SHA-1算法的实现
Digest：引入trait，编译器才能知道Sha1拥有digest()这个方法

pub trait Digest {
    fn new() -> Self;
    fn update(&mut self, data: impl AsRef<[u8]>);
    fn finalize(self) -> Output<Self>;
    fn digest(data: impl AsRef<[u8]>) -> Output<Self>; // 关联函数
}

2. crate版本

sha1 = 0.6旧版本报错 ```bash sha1/src$ cargo build Updating ustc index Locking 3 packages to latest compatible versions Adding hex v0.4.3 Adding sha1 v0.6.1 (latest: v0.10.6) Adding sha1_smol v1.0.1 Downloaded sha1 v0.6.1 (registry ustc) Downloaded sha1_smol v1.0.1 (registry ustc) Downloaded 2 crates (12.7 KB) in 8.23s Compiling sha1_smol v1.0.1 Compiling hex v0.4.3 Compiling sha1 v0.6.1 Compiling sha1 v0.1.0 (/home/…/sha1) warning: unused import: Digest –> src/main.rs:1:18 | 1 | use sha1::{Sha1, Digest}; | ^^^^^^ | = note: #[warn(unused_imports)] on by default

error[E0308]: mismatched types –> src/main.rs:6:29 | 6 | let hash = Sha1::digest(password.as_bytes()); | ———— ^^^^^^^^^^^^^^^^^^^ expected &Sha1, found &[u8] | | | arguments to this function are incorrect | = note: expected reference &Sha1 found reference &[u8]

+ `sha1 = 0.10`最新版本
```bash
sha1/src$ cargo build
    Updating `ustc` index
     Locking 10 packages to latest compatible versions
      Adding block-buffer v0.10.4
      Adding cfg-if v1.0.3
      Adding cpufeatures v0.2.17
      Adding crypto-common v0.1.6
      Adding digest v0.10.7
      Adding generic-array v0.14.7 (latest: v1.2.0)
      Adding libc v0.2.175
    Updating sha1 v0.6.1 -> v0.10.6
      Adding typenum v1.18.0
      Adding version_check v0.9.5
  Downloaded block-buffer v0.10.4 (registry `ustc`)

1. Sha1哈希算法

SHA-1 结构与输出
- 不可逆、单向的加密摘要函数—原则上不能“反向”还原输入
- 输出长度为160位（20字节），常用hex 表示为 40 位十六进制字符串
安全性缺陷与弃用状态
- 已知 SHA-1 存在碰撞攻击风险，被认为在安全上“已废弃”
破解方法
- 暴力猜测+ 哈希比较
  - 对 wordlist 中每个候选做 SHA-1，然后比对。
  - 若wordlist不够，尝试所有可能的字符组合
- Rainbow table 查表
- Key stretching提升计算成本
  2. Rust增量开发
  
  步骤提示：参数解析、字典加载（wordlist）、计算与对比、输出结果
  
  程序入口与错误处理
程序入口 fn main()
返回值与错误处理 Result<(), Box<dyn Error>>
使用语法糖?处理错误
命令行参数处理

env::args().collect::<Vec<String>>()

//std::env imports the module env from the standard library
//env::args()calls the args function from this module and returns an iterator which can be “collected” into a Vec<String> , a Vector of String objects. A Vector is an array type that can be resized.
use std::env;

命令行参数数量检查
常量检查：SHA-1哈希字符串是否符合长度
- const SHA1_HEX_STRING_LENGTH: usize = 40;

文件读取与缓冲区

std::fs::File::open
BufReader提高读取性能
逐行读取
字符串、字节处理
String vs &str
.trim()去除换行和空白
集合与迭代器

控制流

分支结构/循环结构

return

Ok(())

3. 组合子——集合与迭代器

集合

Rust中常见的集合有哪些

a[]数组

vec![]动态数组

HashMap.new()映射
迭代器Iterator

An Iterator is an object that enables developers to traverse collections.

Owned vs Borrowed Iterator

fn vector() {
let v = vec![
    1, 2, 3,];
// .into_iter(): 所有权
for x in v.into_iter() {  
  println!("{}", x);
}
// you can't longer use v

fn hashmap() {
  let mut h = HashMap::new();
  h.insert(String::from("Hello"), String::from("World"));
  // .iter(): 借用
  for (key, value) in h.iter() {
    println!("{}: {}", key, value);
  }
}
}

迭代器使用

for .. in ..循环
for_each()函数
.collect()将迭代器转换为集合

举个栗子1：Collection

fn main() {
    let nums = 1..=10; // 迭代器: 1 到 10

    let total: i32 = nums.clone().sum();
    println!("sum() => {}", total); // 55

    let first_over_5 = nums.clone().find(|&x| x > 5);
    println!("find() => {:?}", first_over_5); // Some(6)

    let evens: Vec<_> = nums.clone().filter(|x| x % 2 == 0).collect();
    println!("collect() => {:?}", evens); // [2, 4, 6, 8, 10]
}

举个栗子2：组合子

fn main() {
    let nums = 1..=10;

    let total: i32 = nums
        .filter(|x| x % 2 == 0)
        .filter(|x| *x > 5)
        .sum();

    println!("结果: {}", total); // 结果: 24  (6 + 8 + 10)
}

组合子Combinator

.filter()

.inspect

fn inspect() {
let v = vec![-1, 2, -3, 4, 5].into_iter();
let _positive_numbers: Vec<i32> = v
    //检查迭代的每个值
    .inspect(|x| println!("Before filter: {}", x))
    .filter(|x: &i32| x.is_positive())
    .inspect(|x| println!("After filter: {}", x))
    .collect();
}

src$ cargo run 
   Compiling myhello v0.1.0 (/home/rust/myhello)
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 2.67s
     Running `/home/rust/myhello/target/debug/myhello`
Before filter: -1
Before filter: 2
After filter: 2
Before filter: -3
Before filter: 4
After filter: 4
Before filter: 5
After filter: 5

.map()将元素进行类型转换
.filter_map()：相当于.filter和.map的组合，可用于处理Option类型数据
.chain()：合并两个iterators

fn main() {
let a = vec!["1","2","-1","4","-4","100","invalid","Not a number"," ",];
let _only_positive_numbers: Vec<i64> = a
.into_iter()
//.inspect(|x| println!("before filter_map: {}", x))
.filter_map(|x| x.parse::<i64>().ok())
//.inspect(|x| println!("After filter_map: {}", x))
.filter(|x| x > &0)
//.inspect(|x| println!("After filter: {}", x))
.collect();
}

Setup

安装rustup

cargo 使用准备

配置编辑器

Cargo与Rust项目

项目管理

0. init

1. run

Our demo

1. use

2. crate版本

1. Sha1哈希算法

2. Rust增量开发

程序入口与错误处理

命令行参数处理

文件读取与缓冲区

字符串、字节处理

集合与迭代器

控制流

return

Ok(())