学习Rust的第28天：rm in Rust

Pseudo Code 伪代码

function remove(path)->result{fs::remove_dir_all(src)?;Ok(())
}args = command_line_arguments
remove the first element of the args vector
if args.length == 0 {print error_message
}
else if args.contains("--help") {print help_message
} else {for path in args {result = remove(path);error handling}
}

Setup 设置

So let’s create a struct an implementation block containing the following methods:
因此，让我们创建一个 struct 包含以下方法的实现块：

1. new() : To instantiate out struct
   new() ：实例化结构体
2. help() : To print the help text if arguments contain --help
   help() ：如果参数包含 --help 则打印帮助文本
3. not_enough_arguments() : If the user has not supplied enough arguments
   not_enough_arguments() ：如果用户没有提供足够的参数
4. rm_dir_all(path) : To remove the specified folder
   rm_dir_all(path) : 删除指定文件夹
5. run() : To carry out logic and error handling, calling the other functions..
   run() ：执行逻辑和错误处理，调用其他函数。

We will do all of this in a lib.rs file and then call our run function in a binary crate to create and executable file
我们将在 lib.rs 文件中完成所有这些操作，然后在二进制包中调用 run 函数来创建可执行文件

pub struct Config<'a> {pub files: &'a Vec<String>,
}impl Config<'_> {pub fn new(args: &Vec<String>) -> Config{Config{files: args}}fn not_enough_arguments(){eprintln!("rm: missing operand");eprintln!("For help use: rm --help");}fn help() {eprintln!("This is a cheap little clone of the rm utility in the GNU core utilities, the catch is that I made it in rust, check out more of my work at medium: https://shafinmurani.medium.com");eprintln!("This is recursive by default so dont worry about anything, just run it :D");eprintln!("To use this util: rm path1 path2 ... pathN");}fn rm_dir_all(){//We'll leave this function empty and come back to it later on}pub fn run(&self){if self.files.len() == 0 {Self::not_enough_arguments();} else if self.files.contains(&String::from("--help")) {Self::help();} else {for path in self.files {// We will call the rm_dir_all() function here// error handling here}}}
}

Okay looks simple enough? let’s break it down and understand it
好吧，看起来够简单吧？让我们分解并理解它

• This code defines a Rust struct named Config, which holds a reference to a vector of strings (files).
  此代码定义了一个名为 Config 的 Rust 结构体，它保存对字符串向量 ( files ) 的引用。
• The Config struct has an associated function new, which takes a reference to a vector of strings (args) and returns a Config instance with args assigned to files.
  Config 结构有一个关联的函数 new ，它引用字符串向量 ( args ) 并返回 Config 实例将 args 分配给 files 。
• There are some helper functions like not_enough_arguments() and help() which provide error messages and usage information, respectively.
  有一些辅助函数，例如 not_enough_arguments() 和 help() ，它们分别提供错误消息和使用信息。
• The run() method of Config is responsible for executing the desired functionality based on the provided arguments.
  Config 的 run() 方法负责根据提供的参数执行所需的功能。
• It checks if there are enough arguments, prints help information if --help is provided, and otherwise iterates over the provided paths to perform the remove operations (which is currently left unimplemented).
  它检查是否有足够的参数，如果提供了 --help 则打印帮助信息，否则迭代提供的路径以执行删除操作（当前未实现）。

Implementing the remove function
实现删除功能

To implement this, we’ll go with a really easy to use function of the std::fs crate, std::fs::remove_dir_all if the specified path is a directory and std::fs::remove_file if the specified path is a file
为了实现这一点，我们将使用 std::fs 箱的一个非常易于使用的功能，如果指定的路径是目录，则使用 std::fs::remove_dir_all ；如果指定的路径是目录，则使用 std::fs::remove_file 指定路径是一个文件

You can check out the documentations of these function here:
您可以在此处查看这些函数的文档：remove_dir_all in std::fs - Rust (rust-lang.org)

Let’s build the function and break it down
让我们构建函数并分解它

//we will also import the following modules
use std::path::Path;
use std::{fs, io}fn rm_dir_all(src: &String) -> io::Result<()> {let src_path = Path::new(src);let src_path_buffer = src_path.to_path_buf();if src_path_buffer.is_dir() {fs::remove_dir_all(src)?;Ok(())} else {fs::remove_file(src)?;Ok(())}
}

• The function rm_dir_all takes a reference to a string (src) representing a file or directory path, and returns a result of type io::Result<()>.
  函数 rm_dir_all 获取对表示文件或目录路径的字符串 ( src ) 的引用，并返回 io::Result<()> 类型的结果。
• It first creates a Path instance from the provided src string using Path::new(src).
  它首先使用 Path::new(src) 从提供的 src 字符串创建一个 Path 实例。
• Then, it creates a PathBuf instance from the Path using to_path_buf(), storing it in src_path_buffer.
  然后，它使用 to_path_buf() 从 Path 创建一个 PathBuf 实例，并将其存储在 src_path_buffer 中。
• It checks if the path represented by src_path_buffer is a directory using is_dir(). If it is a directory, it removes the directory and all its contents recursively using fs::remove_dir_all(src)?.
  它使用 is_dir() 检查 src_path_buffer 表示的路径是否是目录。如果它是一个目录，它会使用 fs::remove_dir_all(src)? 递归地删除该目录及其所有内容。
• If the path is not a directory (presumably a file), it attempts to remove the file using fs::remove_file(src)?.
  如果路径不是目录（可能是文件），它会尝试使用 fs::remove_file(src)? 删除文件。
• It returns Ok(()) if the removal operation is successful, otherwise propagates any encountered IO errors.
  如果删除操作成功，它将返回 Ok(()) ，否则传播任何遇到的 IO 错误。

Error Handling 错误处理

Let’s call the rm_dir_all() function in our run() function and handle the propogated errors…
让我们在 run() 函数中调用 rm_dir_all() 函数并处理传播的错误......

use std::path::Path;
use std::{fs, io};pub struct Config<'a> {pub files: &'a Vec<String>,
}impl Config<'_> {pub fn new(args: &Vec<String>) -> Config{Config{files: args}}fn not_enough_arguments(){eprintln!("rm: missing operand");eprintln!("For help use: rm --help");}fn help() {eprintln!("This is a cheap little clone of the rm utility in the GNU core utilities, the catch is that I made it in rust, check out more of my work at medium: https://shafinmurani.medium.com");eprintln!("This is recursive by default so dont worry about anything, just run it :D");eprintln!("To use this util: rm path1 path2 ... pathN");}fn rm_dir_all(src: &String) -> io::Result<()> {let src_path = Path::new(src);let src_path_buffer = src_path.to_path_buf();if src_path_buffer.is_dir() {fs::remove_dir_all(src)?;Ok(())} else {fs::remove_file(src)?;Ok(())}}pub fn run(&self){if self.files.len() == 0 {Self::not_enough_arguments();} else if self.files.contains(&String::from("--help")) {Self::help();} else {for path in self.files {let result = Self::rm_dir_all(path);match result {Ok(()) => {},Err(e) => eprintln!("Application Error: `{}` {}" path, e),};}}}
}

Binary Crate 二进制箱

That’s all for the library crate, now let’s get to our main.rs file
这就是库箱的全部内容，现在让我们进入 main.rs 文件

use rm::Config;
use std::env;fn main(){let mut args: Vec<String> = env::args().collect();args.remove(0);let config = Config::new(&args);config.run();
}

And that’s all we have to do, let’s test it out and see how it works.
这就是我们所要做的，让我们测试一下，看看它是如何工作的。

Execution 执行

That is what the tree of my /tmp directory looks like, I compiled the rust code to a binary using cargo build --release
这就是我的 /tmp 目录树的样子，我使用 cargo build --release 将 Rust 代码编译为二进制文件

.
├── rm
├── test_dir
│   ├── test_dir_in_dir
│   └── test_file_in_dir
└── test_file

To delete the test_dir we can run the following command
要删除 test_dir 我们可以运行以下命令

# ./rm test_dir/

The tree looks like this rn
这棵树看起来像这样

.
├── rm
└── test_file

Removing the test_file 删除 test_file

./rm test_dir/

tree: 树：

.
└── rm