https://github.com/wangrunji0408/call-dispatch-macro

[WIP] Generate function call dispatcher in Rust procedural macro.
https://github.com/wangrunji0408/call-dispatch-macro

Last synced: 3 months ago
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[WIP] Generate function call dispatcher in Rust procedural macro.

• Host: GitHub
• URL: https://github.com/wangrunji0408/call-dispatch-macro
• Owner: wangrunji0408
• Created: 2021-03-02T11:28:05.000Z (almost 4 years ago)
• Default Branch: main
• Last Pushed: 2021-03-02T11:56:58.000Z (almost 4 years ago)
• Last Synced: 2024-08-03T01:38:44.923Z (6 months ago)
• Language: Rust
• Size: 4.88 KB
• Stars: 6
• Watchers: 2
• Forks: 1
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

        
# call-dispatch-macro

[![Actions Status](https://github.com/wangrunji0408/call-dispatch-macro/workflows/CI/badge.svg)](https://github.com/wangrunji0408/call-dispatch-macro/actions)

Generate function call dispatcher in Rust procedural macro.

🚧 Working In Progress 🚧

## Usage

```rust

use call_dispatch_macro::call_dispatch;

// Define a struct.

struct Syscall;

// Put `call_dispatch` attribute on the impl block.

#[call_dispatch]

impl Syscall {

    // Mark the dispatcher function.

    #[dispatcher(match_arm_prefix = "sys")]

    fn dispatch(&mut self, num: u32, args: [usize; 6]) -> Option {

        // The body will be rewritten by the macro.

        panic!("code generated by macro")

        // ======== Generated Code Start ========

        match num {

            sys::SYS_READ => Some(self.sys_read(args[0] as _, args[1] as _, args[2] as _)),

            sys::SYS_WRITE => Some(self.sys_write(args[0] as _, args[1] as _, args[2] as _)),

            _ => None,

        }

        // ========= Generated Code End =========

    }

    // Mark the function to be dispatched.

    #[call]

    fn sys_read(&mut self, fd: i32, buf: *mut u8, len: usize) -> i32 {

        println!("sys_read: fd={:?}, buf=({:?}; {:?})", fd, buf, len);

        1

    }

    #[call]

    fn sys_write(&mut self, fd: i32, buf: *const u8, len: usize) -> i32 {

        println!("sys_write: fd={:?}, buf=({:?}; {:?})", fd, buf, len);

        2

    }

}

// Define constants for match number.

mod sys {

    pub const SYS_READ: u32 = 1;

    pub const SYS_WRITE: u32 = 2;

}

fn main() {

    let mut syscall = Syscall;

    assert_eq!(syscall.dispatch(0, [1, 2, 3, 4, 5, 6]), None);

    assert_eq!(syscall.dispatch(1, [1, 2, 3, 4, 5, 6]), Some(1));

    assert_eq!(syscall.dispatch(2, [1, 2, 3, 4, 5, 6]), Some(2));

}

```